JP7714938B2 - Gate insert, fixing unit, and preform manufacturing method - Google Patents

Description

The technical field of the present invention relates to gate inserts, fixing units, and preform manufacturing methods.

The preform is formed, for example, by injection molding. Patent Document 1 describes an example of a conventional preform.

JP 2016-193618 A

During the preform molding process, cold slugs can form in the gate insert, which can cause molding defects in the main body of the preform.

The gate insert of the present invention is a gate insert of a fixed unit for molding a preform, and is provided with a protrusion molding portion that corresponds to the protrusion on the bottom of the preform, and the protrusion molding portion includes a regulating portion configured to prevent the movement of the cold slug.
With the gate insert, the movement of the cold slug is prevented by the restricting portion, so the cold slug is less likely to move into the molding space of the fixing unit corresponding to the main body of the preform, which reduces the likelihood of molding defects related to the main body of the preform.

In one example of the gate insert, the restricting portion is configured to make a full turn around the central axis of the gate insert.
The gate insert is highly effective in preventing the movement of cold slag.

In one example of the gate insert, the restriction portion is provided closer to the gate land in a direction parallel to the central axis of the gate insert.
The gate insert makes it easier for cold slag to accumulate in the area near the gate land.

In one example of the gate insert, the regulating portion is configured to protrude relative to the base portion of the protrusion molding portion and includes a first side surface, a second side surface, and an intermediate surface, the first side surface being located between the intermediate surface and the gate land, and the second side surface being located between the intermediate surface and the base portion.
According to the gate insert, when the cold slag is in contact with the first side surface, the cold slag is more likely to remain there.

In one example of the gate insert, the intermediate surface is a curved surface, and the radius of the arc representing the intermediate surface is in the range of 2 mm or less.
The gate insert can more easily provide the effect of preventing the movement of cold slag.

In one example of the gate insert, the angle of inclination of the first side surface relative to the radial direction of the gate insert is in the range of 30° or greater.
The gate insert can more easily provide the effect of preventing the movement of cold slag.

In one example of the gate insert, the angle of inclination of the first side surface relative to the radial direction of the gate insert is in the range of 90° or less.
The gate insert makes it easier for the protrusions of the preform to separate from the protrusion-forming portion.

The fixing unit according to the present invention comprises the gate insert.
The fixing unit reduces the likelihood of molding defects occurring in the main body of the preform.

The method for producing a preform according to the present invention includes a molding step of molding a preform using the fixing unit.
According to the above manufacturing method, molding defects relating to the main body of the preform are less likely to occur.

The gate insert, fixing unit, and preform manufacturing method of the present invention reduce molding defects in the main body of the preform.

Cross-section of a preform. FIG. 2 is an enlarged view of a portion of FIG. 1; Cross-section of an injection mold. FIG. 10 shows the gate in an open state. A diagram showing the gate in a closed state. FIG. 4 is an enlarged view of a portion of FIG. 3 . FIG. 7 is an enlarged view of a portion of FIG. 6; FIG. 8 is an enlarged view of a portion of FIG. 7 . FIG. 7 is an enlarged view of a portion of FIG. 6; 10 is a cross-sectional view of another gate insert. Enlarged view of the restricting part. FIG.

(First embodiment)
Fig. 1 shows an example of a preform P10. Fig. 3 shows an example of an injection molding die 10. The preform P10 is manufactured, for example, by the injection molding die 10. The preform P10 is used, for example, to manufacture PET bottles.
In the description of the preform P10 and the injection mold 10, reference is made to the X1, X2, Y1, Y2, Z1, and Z2 directions.

The X1 direction and the X2 direction are parallel to the X axis. The X1 direction is opposite to the X2 direction. The X direction collectively refers to the X1 direction and the X2 direction.
The Y1 direction and the Y2 direction are parallel to the Y axis. The Y1 direction is opposite to the Y2 direction. The Y direction collectively refers to the Y1 direction and the Y2 direction.
The Z1 direction and the Z2 direction are parallel to the Z axis. The Z1 direction is opposite to the Z2 direction. The Z direction collectively refers to the Z1 direction and the Z2 direction.
Of the cross sections relating to the preform P10 and the injection molding die 10, the cross sections parallel to the X-axis and Y-axis are referred to as reference cross sections.

1 shows a reference cross section of the preform P10. The axial direction of the preform P10 is parallel to the central axis of the preform P10. The axial direction of the preform P10 is parallel to the X direction. The radial direction of the preform P10 is perpendicular to the axial direction of the preform P10.
The configuration of the preform P10 can be selected arbitrarily. The configuration of the preform P10 is not limited to the exemplified configuration. The preform P10 includes a main body P100. The main body P100 includes, for example, a bottom portion P110, a body portion P120, and an opening P130.

The main body P100 is a cylinder. A space is formed inside the main body P100. The space inside the main body P100 is referred to as a main body space P101.
The trunk portion P120 constitutes the main portion of the main body P100. The trunk portion P120 is divided into, for example, a main trunk portion P121 and a sub-trunk portion P122.
The outer diameter of the main body portion P121 is constant. The sub-body portion P122 is located in the X2 direction relative to the main body portion P121. The sub-body portion P122 is tapered. The outer diameter of the sub-body portion P122 increases as it progresses in the X2 direction.

The bottom portion P110 is located in the X1 direction relative to the body portion P120. The shape of the bottom portion P110 is hemispherical. The bottom portion P110 includes a tip portion P111. The tip portion P111 of the bottom portion P110 corresponds to the apex of the hemisphere.
The opening P130 is located in the X2 direction relative to the body P120. The opening P130 includes an opening end P131. The main body space P101 opens to the opening end P131.

The opening P130 includes a male thread P132 and a support ring P133. The male thread P132 and the support ring P133 are provided on the outer periphery of the opening P130. The male thread P132 is positioned in the X1 direction relative to the open end P131. The support ring P133 is positioned in the X1 direction relative to the male thread P132.

Please refer to Figure 2. Figure 2 shows an enlarged view of the bottom portion P110 of the preform P10 shown in Figure 1. The preform P10 includes a protrusion P200. The protrusion P200 is provided at the tip portion P111 of the bottom portion P110. The protrusion P200 has the form of a short gate.

The protrusion P200 protrudes in the X1 direction from the tip P111 of the bottom P110. The central axis of the protrusion P200 is coaxial with the central axis of the preform P10.
The shape of the protrusion P200 is determined by, for example, a basic solid. The basic solid corresponding to the protrusion P200 is a cylinder. The side surfaces of the basic solid are curved. The top and bottom surfaces of the basic solid are flat. The outer diameter of the basic solid decreases in the X1 direction.

In the reference cross section, the basic solid is represented by a curve LP1, a curve LP2, a line segment LP3, and a line segment LP4.
The curve LP1 indicates the side surface of the basic solid. The curve LP1 is represented by a solid curve LP11 and a two-dot chain curve LP12. The curve LP1 is a circular arc. The center of the arc is determined outside the basic solid.

The curve LP2 indicates the side surface of the basic solid. The curve LP2 is represented by a solid curve LP21 and a two-dot chain curve LP22. The curve LP2 is a circular arc. The center of the circular arc is determined outside the basic solid.
The line segment LP3 indicates the top surface of the basic solid body, and is represented by a solid line segment LP31 and two-dot chain line segments LP32 and LP33.
The dashed two-dot line segment LP4 indicates the bottom surface of the basic solid.

The protrusion P200 includes a side surface P201 and a top surface P202. The side surface P201 is defined by a side surface of the basic solid. The top surface P202 is defined by a top surface of the basic solid. The protrusion P200 includes a base portion P210, a recess P220, a top portion P230, and an annular portion P240.
The base portion P210 is located in the X1 direction relative to the bottom portion P110 of the preform P10. The recessed portion P220 is located in the X1 direction relative to the base portion P210. The top portion P230 is located in the X1 direction relative to the recessed portion P220. The annular portion P240 is located in the X1 direction relative to the top portion P230.

The base portion P210 connects to the tip portion P111 of the bottom portion P110 of the preform P10. The shape of the base portion P210 corresponds to the shape of the basic solid. The outer diameter of the base portion P210 decreases in the X1 direction.

The base portion P210 includes a side surface P211. The side surface P211 of the base portion P210 forms part of the side surface P201 of the protrusion P200. The side surface P211 of the base portion P210 is defined by the side surface of the basic solid. Solid curves LP11 and LP21 indicate the side surface P211 of the base portion P210.
The side surface P211 of the base portion P210 is a curved surface. In the reference cross section, the side surface P211 of the base portion P210 is represented by an arc. The center of the arc is determined outside the protrusion P200.

The recess P220 is configured to be recessed relative to the basic solid. The recess P220 includes a side surface P221. The side surface P221 of the recess P220 forms a part of the side surface P201 of the protrusion P200.
The side surface P221 of the recess P220 does not overlap with the side surface of the basic solid. The side surface P221 of the recess P220 is located radially inward of the side surface of the basic solid. The side surface P221 of the recess P220 includes a flat surface and a curved surface.

The top portion P230 includes a side surface P231. The side surface P231 of the top portion P230 forms a part of the side surface P201 of the protrusion P200. The side surface P231 of the top portion P230 is a curved surface.
The side surface P231 of the top portion P230 does not overlap with the side surface of the basic solid. The side surface P231 of the top portion P230 is located inward in the radial direction of the preform P10 with respect to the side surface of the basic solid.

The top portion P230 includes a top surface P232. The top surface P232 of the top portion P230 constitutes the top surface P202 of the protrusion P200. The top surface P232 of the top portion P230 is a flat surface.
A top surface P232 of the top portion P230 overlaps with the top surface of the basic solid. A solid line segment LP31 indicates the top surface P232 of the top portion P230.

The annular portion P240 is connected to the outer periphery of the top portion P230. The annular portion P240 includes an inner circumferential surface P241. The inner circumferential surface P241 of the annular portion P240 defines the space of the annular portion P240.

Please refer to Figure 3. Figure 3 shows a reference cross section of a portion of the injection molding die 10. The injection molding die 10 molds a preform P10 from a resin material. The configuration of the injection molding die 10 can be selected arbitrarily. The configuration of the injection molding die 10 is not limited to the configuration shown in the example.

The injection molding die 10 supplies resin material using, for example, a hot runner system. The injection molding die 10 includes, for example, a hot runner unit 20 and a molding unit 30. The hot runner unit 20 supplies molten resin material to the molding unit 30. The molding unit 30 molds the molten resin material into a preform P10.
The hot runner unit 20 includes, for example, a heating manifold, a nozzle tip 21, a heater 22, a heat insulator 23, and a valve stem 24. The heat insulator 23 is sometimes called a nozzle tip insulator.

The nozzle tip 21 is connected to the heating manifold. The central axis of the nozzle tip 21 is parallel to the X-axis. A flow path 21A is formed inside the nozzle tip 21. The flow path 21A of the nozzle tip 21 is connected to a flow path of the heating manifold. The resin material flows from the flow path of the heating manifold to the flow path 21A of the nozzle tip 21.
The nozzle tip 21 includes a tip portion 21B. The tip portion 21B of the nozzle tip 21 includes an opening 21C. An injection hole 21D is formed in the opening 21C. The injection hole 21D is connected to the flow path 21A of the nozzle tip 21.

The heater 22 is provided on the outer periphery of the nozzle tip 21. The heater 22 heats the nozzle tip 21. The heat from the heater 22 is transferred to the resin material via the nozzle tip 21. The heat insulating insulator 23 is provided on the outer periphery of the heater 22. The heat insulating insulator 23 prevents heat transfer between the heater 22 and the molding unit 30.

A portion of the valve stem 24 is positioned in the flow path 21A of the nozzle tip 21. The central axis of the valve stem 24 is parallel to the X axis. The valve stem 24 can move in the X direction relative to the nozzle tip 21. The valve stem 24 includes a tip 24A. The tip 24A of the valve stem 24 is configured to be able to pass through the injection hole 21D of the nozzle tip 21.

The configuration of the molding unit 30 can be selected arbitrarily. The configuration of the molding unit 30 is not limited to the configuration shown in the example. The molding unit 30 includes, for example, a fixed unit 40, a neck ring 60, and a movable unit 70. The fixed unit 40 is located in the X2 direction relative to the hot runner unit 20. The neck ring 60 is located in the X2 direction relative to the fixed unit 40. The movable unit 70 is located in the X2 direction relative to the neck ring 60.

The configuration of the fixing unit 40 can be selected arbitrarily and is not limited to the configuration illustrated in the example. The fixing unit 40 includes, for example, a plate, a gate insert 100, and a cavity 50.
The gate insert 100 is attached to the plate. The gate insert 100 is configured to be detachable from the plate.
The cavity 50 is located in the X2 direction relative to the gate insert 100. The cavity 50 is attached to a plate. The cavity 50 is configured to be detachable from the plate.

Please refer to Figures 4 and 5. Figures 4 and 5 show enlarged views of the gate insert 100 and the like shown in Figure 3. The configuration of the gate insert 100 can be selected arbitrarily. The configuration of the gate insert 100 is not limited to the configuration shown in the example.
Examples of materials for the gate insert 100 include ferrous and non-ferrous materials. Examples of ferrous materials include steel. Examples of steel include pre-hardened steel, quenched and tempered steel, stainless steel, and aged steel.

The axial direction of the gate insert 100 is parallel to the central axis of the gate insert 100 (hereinafter referred to as the "gate central axis LC"). The axial direction of the gate insert 100 is parallel to the X direction. The radial direction of the gate insert 100 is perpendicular to the axial direction of the gate insert 100.
The gate insert 100 includes a first end surface 100A and a second end surface 100B. The first end surface 100A is located in the X1 direction relative to the center of the gate insert 100 in the X direction. The second end surface 100B is located in the X2 direction relative to the center of the gate insert 100 in the X direction.

The gate insert 100 includes a placement portion 110. A space is formed in the placement portion 110. The space in the placement portion 110 is referred to as the placement space 110A. The placement portion 110 includes an inner surface 111. The inner surface 111 defines the placement space 110A. The placement space 110A opens to the second end surface 100B of the gate insert 100.

The tip 21B of the nozzle tip 21 is positioned in the arrangement space 110A. The heat insulating insulator 23 is positioned in the arrangement space 110A. The heat insulating insulator 23 is positioned between the tip 21B of the nozzle tip 21 and the inner surface 111 of the arrangement portion 110. The heat insulating insulator 23 prevents heat transfer between the tip 21B of the nozzle tip 21 and the gate insert 100.

The gate insert 100 includes a gate land 120. The gate land 120 is positioned in the X2 direction relative to the placement portion 110. A flow path 120A is formed in the gate land 120. The gate land 120 includes an inner surface 121. The inner surface 121 defines the flow path 120A of the gate land 120.

The flow path 120A includes an inlet 120B. The inlet 120B is located in the X1 direction relative to the center of the flow path 120A in the X direction. The ejection hole 21D of the nozzle tip 21 is connected to the inlet 120B.
The flow channel 120A includes a gate 120C. The gate 120C is located in the X2 direction relative to the center of the flow channel 120A in the X direction.

The gate insert 100 includes a molding portion 130. The molding portion 130 is located in the X2 direction relative to the gate land 120. A space is formed in the molding portion 130. The space of the molding portion 130 is referred to as a first internal space S10.
The molding portion 130 includes an inner surface 131. The inner surface 131 defines a first internal space S10. The gate 120C is connected to the first internal space S10. The first internal space S10 opens to a second end surface 100B of the gate insert 100.

The first internal space S10 corresponds to the bottom P110 and the protrusion P200 of the preform P10. The inner surface 131 of the molding part 130 corresponds to the outer surface of the bottom P110 and the outer surface of the protrusion P200 of the preform P10.
The molding portion 130 is divided into a bottom molding portion 140 and a protrusion molding portion 200. The first internal space S10 is divided into a bottom space S11 and a protrusion space S12. The inner surface 131 of the molding portion 130 is divided into an inner surface 141 and an inner surface 201.

The bottom space S11 is a space formed in the bottom molding portion 140. The bottom space S11 corresponds to the bottom P110 of the preform P10.
The bottom molding portion 140 includes an inner surface 141. The inner surface 141 defines a bottom space S11. The inner surface 141 corresponds to the outer surface of the bottom portion P110 of the preform P10.

The protrusion space S12 is a space formed in the protrusion forming portion 200. The protrusion space S12 corresponds to the protrusion P200 of the preform P10.
The protrusion molding portion 200 includes an inner surface 201. The inner surface 201 defines a protrusion space S12. The inner surface 201 of the protrusion molding portion 200 corresponds to the outer surface of the protrusion P200 of the preform P10.

4 and 5, the tip 24A of the valve stem 24 moves in and out of the flow passage 120A of the gate land 120.
The position of the valve stem 24 in the X direction is selected to be, for example, an open position or a closed position. Figure 4 shows the state in which the valve stem 24 is in the open position. Figure 5 shows the state in which the valve stem 24 is in the closed position.

When the valve stem 24 is in the open position, for example, the following situation can be seen. The tip 24A of the valve stem 24 is positioned in the flow path 21A of the nozzle tip 21. The tip 24A of the valve stem 24 is positioned in the X1 direction relative to the injection hole 21D of the nozzle tip 21.

The injection hole 21D of the nozzle tip 21 is open. The flow path 120A of the gate land 120 is open. The flow path 21A of the nozzle tip 21 is connected to the flow path 120A of the gate land 120 via the injection hole 21D.
The resin material flows through the flow path 21A of the nozzle tip 21, the injection hole 21D, the flow path 120A of the gate land 120, and the first internal space S10 in this order.

When the valve stem 24 is in the open position, the position of the valve stem 24 is changed to the closed position by moving the valve stem 24 in the X2 direction.
When the valve stem 24 is in the closed position, the position of the valve stem 24 is changed to the open position by moving the valve stem 24 in the X1 direction.

When the valve stem 24 is in the closed position, the following situation can be seen, for example: The tip 24A of the valve stem 24 is positioned at the injection hole 21D of the nozzle tip 21 and the flow path 120A of the gate land 120.
The injection hole 21D of the nozzle tip 21 and the flow passage 120A of the gate land 120 are closed by the valve stem 24. The flow passage 21A of the nozzle tip 21 is not connected to the flow passage 120A of the gate land 120.

See Fig. 3. The configuration of the cavity 50 can be selected arbitrarily and is not limited to the configuration shown in the example.
Examples of materials for the cavity 50 include ferrous and non-ferrous materials. Examples of ferrous materials include steel. Examples of steel include pre-hardened steel, quenched and tempered steel, stainless steel, and aged steel.

The axial direction of the cavity 50 is parallel to the central axis of the cavity 50. The axial direction of the cavity 50 is parallel to the X direction. The radial direction of the cavity 50 is perpendicular to the axial direction of the cavity 50.
The cavity 50 includes a first end surface 50A and a second end surface 50B. The first end surface 50A is located in the X1 direction relative to the center of the cavity 50 in the X direction. The second end surface 50B is located in the X2 direction relative to the center of the cavity 50 in the X direction.

A space is formed inside the cavity 50. The space inside the cavity 50 is referred to as a second internal space S20. The cavity 50 includes an inner surface 51. The inner surface 51 defines the second internal space S20.
The second internal space S20 opens to the first end surface 50A of the cavity 50. The second internal space S20 opens to the second end surface 50B of the cavity 50. The second internal space S20 is connected to the first internal space S10. The second internal space S20 corresponds to the main body portion P121 of the body portion P120 of the preform P10.

Please refer to Fig. 3. The configuration of the neck ring 60 can be selected arbitrarily, and is not limited to the configuration shown in the example.
The neck ring 60 is located in the X2 direction relative to the cavity 50. The neck ring 60 is configured to be able to fit into the cavity 50. The neck ring 60 is configured to be able to move in the X direction relative to the cavity 50.

Examples of materials for the neck ring 60 include ferrous and non-ferrous materials. Examples of ferrous materials include steel. Examples of steel include pre-hardened steel, quenched and tempered steel, stainless steel, and aged steel.
The axial direction of the neck ring 60 is parallel to the central axis of the neck ring 60. The axial direction of the neck ring 60 is parallel to the X direction. The radial direction of the neck ring 60 is perpendicular to the axial direction of the neck ring 60.

The neck ring 60 is configured to be divisible into a plurality of ring elements. The plurality of ring elements includes, for example, a first ring element and a second ring element. The first ring element constitutes one half of the neck ring 60. The second ring element constitutes the other half of the neck ring 60.
Each ring element is configured to fit together, and each ring element is configured to be movable radially inward and outward of the neck ring 60.

The neck ring 60 is connected to a first actuator that moves the neck ring 60 in the X direction. The first actuator moves each ring element in the radial direction of the neck ring 60.
The state of the neck ring 60 can be selected from, for example, an engaged state or a separated state. The engaged state of the neck ring 60 is a state in which the ring elements are engaged with each other. The separated state of the neck ring 60 is a state in which the ring elements are spaced apart and not engaged with each other.

When the neck ring 60 is in the fitted state, the state of the neck ring 60 is changed to the separated state by moving each ring element outward in the radial direction of the neck ring 60 .
When the neck ring 60 is in the separated state, the state of the neck ring 60 is changed to the fitted state by moving each ring element inward in the radial direction of the neck ring 60.

The neck ring 60 includes a first end surface 60A and a second end surface 60B. The first end surface 60A is located in the X1 direction relative to the center of the neck ring 60 in the X direction. The second end surface 60B is located in the X2 direction relative to the center of the neck ring 60 in the X direction.

A space is formed inside the neck ring 60 in the fitted state. The space inside the neck ring 60 is referred to as a third internal space S30. The neck ring 60 includes an inner surface 61. The inner surface 61 defines the third internal space S30.
The third internal space S30 opens to the first end surface 60A of the neck ring 60. The third internal space S30 opens to the second end surface 60B of the neck ring 60. The third internal space S30 is connected to the second internal space S20. The third internal space S30 corresponds to the sub-body portion P122 and the opening P130 of the body portion P120 of the preform P10.

The position of the neck ring 60 in the X direction is selected to be, for example, the molding position or the removal position. If the neck ring 60 is in an engaged state, the position of the neck ring 60 is changed. If the neck ring 60 is in the removal position, the state of the neck ring 60 is changed.

When the neck ring 60 is at the removal position, the neck ring 60 moves in the X1 direction to change the position of the neck ring 60 to the molding position.
When the neck ring 60 is at the molding position, the neck ring 60 moves in the X2 direction to change the position of the neck ring 60 to the removal position.

When the neck ring 60 is in the molding position, the following situation can be seen, for example: The neck ring 60 is fitted into the cavity 50. The third internal space S30 is connected to the second internal space S20.
When the neck ring 60 is in the removal position, the following situation can be seen, for example: The neck ring 60 is located at a position away from the cavity 50 in the X2 direction, and the third internal space S30 is not connected to the second internal space S20.

Please refer to Fig. 3. The configuration of the movable unit 70 can be selected arbitrarily and is not limited to the configuration shown in the example.
The movable unit 70 includes, for example, a core 71, a lock ring 72, and a movable plate 73. The movable unit 70 is configured to be movable in the X direction relative to the cavity 50 and the neck ring 60.

The core 71 is divided into a first portion 71A and a second portion 71B. The first portion 71A corresponds to the main body space P101 of the preform P10. The second portion 71B is located in the X2 direction relative to the first portion 71A. The second portion 71B is fixed to a movable plate 73.
The lock ring 72 is located in the X2 direction relative to the neck ring 60. The lock ring 72 is configured to be able to fit onto the neck ring 60. The lock ring 72 is fixed to the second portion 71B of the core 71.
The movable plate 73 is positioned in the X2 direction relative to the core 71 and the lock ring 72. The movable plate 73 is connected to a second actuator. The second actuator moves the movable plate 73 in the X direction.

As the position of the movable unit 70 in the X direction, for example, the molding position or the removal position is selected.
When the movable unit 70 is at the removal position, the movable unit 70 moves in the X1 direction to change the position of the movable unit 70 to the molding position.
When the movable unit 70 is at the molding position, the movable unit 70 moves in the X2 direction to change the position of the movable unit 70 to the removal position.

When the neck ring 60 is in the molding position and the movable unit 70 is in the molding position, the following situation can be seen, for example: The first portion 71A of the core 71 is disposed in the first internal space S10, the second internal space S20, and the third internal space S30. The lock ring 72 is fitted to the neck ring 60.
A molding space SM is formed between the inner surface 131 of the molding portion 130 of the gate insert 100, the inner surface 51 of the cavity 50, and the inner surface 61 of the neck ring 60 and the core 71. The molding space SM corresponds to the preform P10.

When the movable unit 70 is in the removal position, for example, the following situation can be observed: The first portion 71A of the core 71 is not positioned in the first internal space S10, the second internal space S20, or the third internal space S30. The lock ring 72 is positioned away from the neck ring 60 in the X2 direction.

The manufacturing method for preform P10 includes a molding process. One cycle of the molding process includes, for example, a mold clamping process, an injection process, a cooling process, and a mold opening process. The mold clamping process is performed after the previous molding process. The injection process is performed after the mold clamping process. The cooling process is performed after the injection process. The mold opening process is performed after the cooling process.

During the clamping process, the following may be observed, for example: The valve stem 24 is in the closed position.
Each ring element of the neck ring 60 moves radially inward of the neck ring 60. The state of the neck ring 60 changes from a separated state to an engaged state. The neck ring 60 moves in the X1 direction. The position of the neck ring 60 changes from the ejection position to the molding position. The neck ring 60 engages with the cavity 50.
The movable unit 70 moves in the X1 direction. The position of the lock ring 72 is changed from the removal position to the molding position. The lock ring 72 fits into the neck ring 60. The first portion 71A of the core 71 is disposed in the first internal space S10, the second internal space S20, and the third internal space S30.

During the injection process, for example, the following occurs: The valve stem 24 moves in the X1 direction. The position of the valve stem 24 changes from the closed position to the open position. The injection hole 21D of the nozzle tip 21 and the flow path 120A of the gate land 120 are opened.
The resin material remaining in the flow path 21A of the nozzle tip 21 flows into the molding space SM via the injection hole 21D of the nozzle tip 21 and the flow path 120A of the gate land 120. The molding space SM is filled with the resin material.
The valve stem 24 moves in the X2 direction. The position of the valve stem 24 changes from the open position to the closed position. The ejection hole 21D of the nozzle tip 21 and the flow path 120A of the gate land 120 are closed by the tip 24A of the valve stem 24.

The cooling process may occur, for example, as follows: The resin material remaining in the molding space SM is cooled by the fixed unit 40, neck ring 60, and movable unit 70. The cooling process continues until the specified cooling time has elapsed.

During the mold opening process, for example, the following occurs: The movable unit 70 moves in the X2 direction; The position of the lock ring 72 is changed from the molding position to the removal position; The first portion 71A of the core 71 is disposed outside the first internal space S10, the second internal space S20, and the third internal space S30.
The neck ring 60 moves in the X2 direction. The position of the neck ring 60 is changed from the molding position to the removal position. The preform P10 moves in the X2 direction together with the neck ring 60. The preform P10 is separated from the gate insert 100 and the cavity 50.
Each ring element of the neck ring 60 moves outward in the radial direction of the neck ring 60. The state of the neck ring 60 is changed from the fitted state to the separated state. The preform P10 is separated from the neck ring 60.

Please refer to Figure 6. Figure 6 shows an enlarged view of a portion of the gate insert 100 shown in Figure 3, focusing on the molding portion 130. The configuration of the bottom molding portion 140 can be selected arbitrarily. The configuration of the bottom molding portion 140 is not limited to the configuration shown in the example.
The shape of the bottom space S11 of the bottom molding portion 140 is determined by, for example, a basic solid. The basic solid corresponding to the bottom space S11 is a hemisphere. In the reference cross section, the basic solid is represented by a curve LQ1 and a line segment LQ2.

The curve LQ1 represents the hemispherical surface of the basic solid. The curve LQ1 is represented by the solid curves LQ11 and LQ12 and the two-dot chain curve LQ13. The curve LQ1 is a circular arc. The center of the circular arc is determined on the cleaved plane of the basic solid.
The line segment LQ2 indicates the cleavage plane of the basic solid.
The shape of the inner surface 141 of the bottom molding portion 140 corresponds to the shape of the bottom space S11. In the reference cross section, the inner surface 141 of the bottom molding portion 140 is indicated by curves LQ11 and LQ12.

Please refer to Figures 7 and 8. Figure 7 shows an enlarged view of the protrusion molding portion 200 shown in Figure 6. Figure 8 shows an enlarged view of a portion of the protrusion molding portion 200 shown in Figure 7. The configuration of the protrusion molding portion 200 can be selected arbitrarily. The configuration of the protrusion molding portion 200 is not limited to the configuration shown in the example.

The shape of the protrusion space S12 of the protrusion forming portion 200 is determined by, for example, a basic solid. The basic solid corresponding to the protrusion space S12 is a column. The side surfaces of the basic solid are curved. The top and bottom surfaces of the basic solid are flat. The outer diameter of the basic solid decreases in the X1 direction.
In the reference cross section, the basic solid is represented by a curve LR1, a curve LR2, a line segment LR3, and a line segment LR4.

The curve LR1 indicates the side surface of the basic solid. The curve LR1 is represented by a solid curve LR11 and a two-dot chain curve LR12. The curve LR1 is a circular arc. The center of the arc is determined outside the basic solid.
The curve LR2 indicates the side surface of the basic solid body. The curve LR2 is represented by a solid curve LR21 and a two-dot chain curve LR22. The curve LR2 is a circular arc. The center of the circular arc is determined outside the basic solid body.
The line segment LR3 indicates the top surface of the basic solid body, and is represented by a solid line segment LR31 and two-dot chain line segments LR32 and LR33.
The dashed two-dot line segment LR4 indicates the bottom surface of the basic solid.

The protrusion molding portion 200 includes an inner surface 201. A side surface P201 is defined by a side surface of the basic solid. A top surface P202 is defined by a top surface of the basic solid.
The protrusion molding portion 200 includes a base portion 210, a restriction portion 220, and a top portion 230. The base portion 210 is located in the X1 direction relative to the bottom molding portion 140. The restriction portion 220 is located in the X1 direction relative to the base portion 210. The top portion 230 is located in the X1 direction relative to the restriction portion 220.

The base portion 210 is connected to the bottom molding portion 140. The shape of the base portion 210 corresponds to the shape of the basic solid. The inner diameter of the base portion 210 decreases in the X1 direction.
The base portion 210 includes an inner surface 211. The inner surface 211 of the base portion 210 forms a part of the side surface P201 of the protrusion P200. The inner surface 211 of the base portion 210 is defined by the side surface of the basic solid. Solid curves LR11 and LR21 indicate the inner surface 211 of the base portion 210.
The inner surface 211 of the base portion 210 is a curved surface. In the reference cross section, the inner surface 211 of the base portion 210 is represented by a circular arc. The center of the circular arc is determined outside the protrusion space S12.

The restricting portion 220 is configured to prevent the cold slug C (see FIG. 9) from moving from the protrusion space S12 toward the bottom space S11. The restricting portion 220 is configured to include a step portion on which the cold slug C is caught.
The restricting portion 220 is configured to be recessed relative to the base solid body. The restricting portion 220 is configured to protrude inward in the radial direction of the gate insert 100 relative to the base portion 210.

The restricting portion 220 is provided closer to the gate land 120 in the X direction. The restricting portion 220 is configured to make one turn around the gate center axis LC.
The restricting portion 220 includes an inner surface 221. The inner surface 221 of the restricting portion 220 constitutes a part of the inner surface 201 of the protrusion forming portion 200. The inner surface 221 of the restricting portion 220 does not overlap with the side surface of the basic solid.

The inner surface 221 of the restricting portion 220 is located radially inward of the gate insert 100 relative to the side surface of the basic solid. The inner surface 221 of the restricting portion 220 is configured to protrude radially inward of the gate insert 100 relative to the inner surface 211 of the base portion 210.
The inner surface 221 of the restricting portion 220 includes a first side surface 221A, a second side surface 221B, and an intermediate surface 221C.

The first side surface 221A of the restricting portion 220 is located between an intermediate surface 221C of the restricting portion 220 and the inner surface 121 of the gate land 120. The first side surface 221A of the restricting portion 220 is connected to the intermediate surface 221C of the restricting portion 220. The first side surface 221A of the restricting portion 220 is flat.
The portion of the restricting portion 220 corresponding to the first side surface 221A has a tapered shape. The inner diameter of the portion of the restricting portion 220 corresponding to the first side surface 221A increases in the X2 direction. The first side surface 221A of the restricting portion 220 is inclined with respect to the gate central axis LC.

The second side surface 221B of the restricting portion 220 is located between the intermediate surface 221C of the restricting portion 220 and the inner surface 211 of the base portion 210. The second side surface 221B of the restricting portion 220 is connected to the intermediate surface 221C of the restricting portion 220. The second side surface 221B of the restricting portion 220 is a flat surface.
The portion of the restricting portion 220 corresponding to the second side surface 221B has a tapered shape. The inner diameter of the portion of the restricting portion 220 corresponding to the second side surface 221B increases in the X2 direction. The second side surface 221B of the restricting portion 220 is inclined with respect to the gate central axis LC.

The intermediate surface 221C of the restricting portion 220 is located between the first side surface 221A of the restricting portion 220 and the second side surface 221B of the restricting portion 220. The intermediate surface 221C of the restricting portion 220 is connected to the respective side surfaces 221A, 221B of the restricting portion 220.
The intermediate surface 221C of the restricting portion 220 is a curved surface. In the reference cross section, the intermediate surface 221C of the restricting portion 220 is represented by an arc. The center of the arc is determined outside the protrusion space S12.

The inner surface 221 of the restricting portion 220 includes a connecting surface 221D. The connecting surface 221D of the restricting portion 220 is located between the second side surface 221B of the restricting portion 220 and the inner surface 211 of the base portion 210. The connecting surface 221D of the restricting portion 220 is connected to the second side surface 221B of the restricting portion 220 and the inner surface 211 of the base portion 210.
The connecting surface 221D of the restricting portion 220 is a curved surface. In the reference cross section, the connecting surface 221D of the restricting portion 220 is represented by an arc. The center of the arc is set in the protrusion space S12.

The top portion 230 includes an inner surface 231. The inner surface 231 of the top portion 230 forms part of the inner surface 201 of the protrusion molding portion 200. The inner surface 231 of the top portion 230 does not overlap with the side surface of the base solid. The inner surface 231 of the top portion 230 is located radially inward of the gate insert 100 relative to the side surface of the base solid.

The inner surface 231 of the top portion 230 is located between the first side surface 221A of the restriction portion 220 and the inner surface 121 of the gate land 120. The inner surface 231 of the top portion 230 is connected to the first side surface 221A of the restriction portion 220 and the inner surface 121 of the gate land 120.
The inner surface 231 of the top portion 230 is a curved surface. In the reference cross section, the inner surface 231 of the top portion 230 is represented by a circular arc. The center of the circular arc is defined in the protrusion space S12.

Please refer to Figure 9. Figure 9 shows a reference cross section of the gate insert 100 when the valve stem 24 is in the closed position.
When the valve stem 24 is in the closed position, a clearance (hereinafter referred to as "gate clearance 122") is formed between the outer peripheral surface 24B of the tip 24A of the valve stem 24 and the inner surface 121 of the gate land 120.

Resin material accumulates in the gate clearance 122. In the cooling process, the resin material accumulated in the gate clearance 122 is cooled, thereby forming the annular portion P240 of the protrusion P200 of the preform P10. The shape of the annular portion P240 corresponds to the shape of the gate clearance 122.

A cold slug C may be formed from the resin material remaining in the gate clearance 122. The cold slug C adheres to the inner surface 121 of the gate land 120. During the molding process in which the cold slug C is formed, an annular portion P240 is molded, with the portion corresponding to the cold slug C missing.

In the manufacturing process of the preform P10, a plurality of molding steps are performed. For any two molding steps included in the plurality of molding steps, the size of the gate clearance 122 may differ at corresponding positions around the gate central axis LC. This may occur, for example, due to differences in pressure distribution around the tip 24A of the valve stem 24.
If the size of the gate clearance 122 is different, the shape of the annular portion P240 formed in each of the two forming steps will also be different.

Please refer to Figure 10. Figure 10 shows a reference cross section of a gate insert (hereinafter referred to as "another gate insert") with a different configuration from gate insert 100. In the following explanation assuming the use of another gate insert, the names and symbols used in the explanation of preform P10 and injection molding die 10 will apply mutatis mutandis.

Other gate inserts do not include the restriction portion 220 and the top portion 230. In other gate inserts, the entire inner surface 201 of the protrusion forming portion 200 is formed by the inner surface 211 of the base portion 210.
When the preform P10 is molded using another gate insert, molding defects may occur in the main body P100 of the preform P10 due to the cold slug C, as described below.

Examples of molding defects related to the main body P100 of the preform P10 include type 1 molding defects and type 2 molding defects. In the following description, when two molding processes are sequentially performed, the molding process that is performed first will be referred to as the "earlier molding process" and the molding process that is performed later will be referred to as the "later molding process."

The first type of molding defect occurs, for example, as follows: In the previous molding process, a cold slug C is formed in the gate clearance 122.
In the injection step of the subsequent molding process, the cold slug C flows from the gate clearance 122 into the molding space SM together with the resin material injected from the nozzle tip 21.

The cold slag C reaches, for example, the forming space SM corresponding to the bottom space S11, the forming space SM corresponding to the second internal space S20, or the forming space SM corresponding to the third internal space S30.
The cold slug C remains in the resin material away from the inner surface 141 of the bottom molding portion 140, the inner surface 51 of the cavity 50, or the inner surface 61 of the neck ring 60, and away from the first portion 71A of the core 71.

In the cooling process of the subsequent molding process, the resin material containing the cold slug C is cooled. The body P100 of the molded preform P10 contains the cold slug C. The cold slug C is contained, for example, in the bottom portion P110, the body portion P120, or the opening portion P130 of the body P100 of the preform P10.

The second type of molding defect occurs, for example, as follows: In the previous molding process, a cold slug C is formed in the gate clearance 122.
In the injection process of the subsequent molding process, the cold slug C flows from the gate clearance 122 into the molding space SM together with the resin material injected from the nozzle tip 21. The behavior of the cold slug C in the molding space SM can be exemplified by the following first to third examples.

In the first example, the cold slug C moves in the molding space SM along the inner surface 201 of the protrusion molding portion 200 and the inner surface 141 of the bottom molding portion 140. The cold slug C adheres to the inner surface 141 of the bottom molding portion 140.
In the second example, the cold slug C moves through the molding space SM along the inner surface 131 of the molding portion 130 and the inner surface 51 of the cavity 50. The cold slug C adheres to the inner surface 51 of the cavity 50.
In the third example, the cold slug C moves through the forming space SM along the inner surface 131 of the forming portion 130, the inner surface 51 of the cavity 50, and the inner surface 61 of the neck ring 60. The cold slug C adheres to the inner surface 61 of the neck ring 60.

In the cooling process of the subsequent molding process, the resin material is cooled with cold slug C adhering to the inner surface 141 of the bottom molding portion 140, the inner surface 51 of the cavity 50, or the inner surface 61 of the neck ring 60. Cold slug C adheres to the outer periphery of the main body P100 of the molded preform P10.

During the mold opening step in the subsequent molding process, the cold slug C separates from the main body P100 of the preform P10 as the preform P10 is separated from the gate insert 100 and the cavity 50. The cold slug C remains on the inner surface 141 of the bottom molding portion 140, the inner surface 51 of the cavity 50, or the inner surface 61 of the neck ring 60.
A recess corresponding to the shape of the cold slug C is formed on the outer periphery of the main body P100 of the preform P10 removed from the injection molding die 10.

Refer to Figure 9. When the gate insert 100 is used to mold the preform P10, molding defects related to the main body P100 of the preform P10 can be reduced, for example, as follows:

In the injection step of the subsequent molding process, the cold slug C flows from the gate clearance 122 into the molding space SM together with the resin material injected from the nozzle tip 21.
The cold slug C is caught by the restricting portion 220 of the protrusion forming portion 200. The movement of the cold slug C from the protrusion space S12 toward the bottom space S11 is prevented by the restricting portion 220. The cold slug C remains in the forming space SM corresponding to the protrusion space S12.

In the cooling step of the subsequent molding process, the resin material is cooled while the cold slug C remains in the molding space SM corresponding to the protrusion space S12. The cold slug C is positioned between the outer periphery of the protrusion P200 of the preform P10 and the restricting portion 220.
The state of the cold slug C in the mold opening step of the subsequent molding process may be as follows: first and second examples.

In the first example, the following situation can be observed: In the mold opening step in the subsequent molding process, as the preform P10 is separated from the gate insert 100 and the cavity 50, the cold slug C separates from the inner surface 201 of the protrusion forming portion 200.
The cold slug C constitutes a part of the protrusion P200 of the preform P10. The protrusion P200 of the preform P10 removed from the injection molding die 10 includes the cold slug C.

In the second example, the following occurs: During the mold opening process in the subsequent molding step, as the preform P10 is separated from the gate insert 100 and cavity 50, the cold slug C separates from the protrusion P200 of the preform P10. The cold slug C remains on the inner surface 201 of the protrusion molding portion 200.

In the molding process performed after the subsequent molding process, the cold slug C remaining on the inner surface 201 of the protrusion molding portion 200 may separate from the inner surface 201 of the protrusion molding portion 200 during the mold opening process. In this case, as in the first example, the cold slug C forms part of the protrusion P200 of the preform P10.

As described above, it is possible to prevent the molding of a preform P10 in which the main body P100 contains cold slug C, or a preform P10 in which a recess caused by cold slug C is formed in the main body P100.

Second Embodiment
The second embodiment is configured based on the first embodiment. In the second embodiment, an example of dimensions related to the gate insert 100 is presented.
The configuration of the inner surface 211 of the base portion 210 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Fig. 8 shows the configuration of Example 1.

The configuration of the first example is similar to the configuration exemplified in the first embodiment. The inner surface 211 of the base portion 210 is a curved surface. In the reference cross section, the inner surface 211 of the base portion 210 is represented by a circular arc.
The configuration of the second example is different from the configuration illustrated in the first embodiment. The inner surface 211 of the base portion 210 is a flat surface. In the reference cross section, the inner surface 211 of the base portion 210 is represented by a line segment.

The radius of the arc representing the inner surface 211 of the base portion 210 is referred to as the "first radius." In the first example configuration, the first radius is greater than 0 mm. In the second example configuration, the first radius is 0 mm. The first radius is selected so as to fall within a reference range for the first radius. An example of the reference range for the first radius is provided below.

The reference range in the first example is a range equal to or greater than the lower limit radius RA1. The reference range in the second example is a range equal to or less than the upper limit radius RA2. The reference range in the third example is a range equal to or greater than the lower limit radius RA1 and equal to or less than the upper limit radius RA2.
The lower limit radius RA1 is selected from, for example, 0.5 mm, 0.8 mm, or 1.0 mm, and the upper limit radius RA2 is selected from, for example, 5.0 mm, 4.0 mm, or 3.0 mm.

The configuration of the intermediate surface 221C of the restricting portion 220 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Fig. 8 shows the configuration of Example 1.
The configuration of the first example is the same as the configuration exemplified in the first embodiment. The intermediate surface 221C of the restricting portion 220 is a curved surface. In the reference cross section, the intermediate surface 221C of the restricting portion 220 is represented by a circular arc.

The configuration of the second example differs from the configuration illustrated in the first embodiment. The intermediate surface 221C of the restricting portion 220 includes two planes. One plane is a plane connected to the first side surface 221A of the restricting portion 220. The other plane is a plane connected to the second side surface 221B of the restricting portion 220. In the reference cross section, the intermediate surface 221C of the restricting portion 220 is represented by two line segments that form an intersection.

The radius of the arc representing the intermediate surface 221C of the restricting portion 220 is referred to as the "second radius." In the first example configuration, the second radius is greater than 0 mm. In the second example configuration, the second radius is 0 mm. The second radius is selected so as to fall within the reference range for the second radius. An example of the reference range for the second radius is provided below.

The reference range in the first example is a range equal to or greater than the lower limit radius RB1. The reference range in the second example is a range equal to or less than the upper limit radius RB2. The reference range in the third example is a range equal to or greater than the lower limit radius RB1 and equal to or less than the upper limit radius RB2.
The lower limit radius RB1 is selected from, for example, 0.0 mm, 0.2 mm, or 0.3 mm, and the upper limit radius RB2 is selected from, for example, 2.0 mm, 1.5 mm, or 1.0 mm.

The configuration of the connection surface 221D of the restricting portion 220 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Fig. 8 shows the configuration of Example 1.
The configuration of the first example is the same as the configuration exemplified in the first embodiment. The connection surface 221D of the restriction portion 220 is a curved surface. In the reference cross section, the connection surface 221D of the restriction portion 220 is represented by an arc.

The configuration of the second example differs from the configuration illustrated in the first embodiment. The connection surface 221D of the restriction portion 220 includes two flat surfaces. One flat surface is connected to the inner surface 211 of the base portion 210. The other flat surface is connected to the second side surface 221B of the restriction portion 220. In the reference cross section, the connection surface 221D of the restriction portion 220 is represented by two line segments that form an intersection.

The radius of the arc representing the connection surface 221D of the restricting portion 220 is referred to as the "third radius." In the first example configuration, the third radius is greater than 0 mm. In the second example configuration, the third radius is 0 mm. The third radius is selected so as to fall within the reference range for the third radius. An example of the reference range for the third radius is provided below.

The reference range in the first example is a range equal to or greater than the lower limit radius RC1. The reference range in the second example is a range equal to or less than the upper limit radius RC2. The reference range in the third example is a range equal to or greater than the lower limit radius RC1 and equal to or less than the upper limit radius RC2.
The lower limit radius RC1 is selected from, for example, 0.0 mm, 0.2 mm, or 0.3 mm, and the upper limit radius RC2 is selected from, for example, 1.5 mm, 1.0 mm, or 0.5 mm.

The configuration of the inner surface 231 of the top portion 230 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Figure 8 shows the configuration of Example 1.
The configuration of the first example is similar to the configuration exemplified in the first embodiment. The inner surface 231 of the top portion 230 is a curved surface. In the reference cross section, the inner surface 231 of the top portion 230 is represented by a circular arc.

The configuration of the second example differs from the configuration illustrated in the first embodiment. The inner surface 231 of the top portion 230 includes two planes. One plane is connected to the first side surface 221A of the restriction portion 220. The other plane is connected to the inner surface 121 of the gate land 120. In the reference cross section, the inner surface 231 of the top portion 230 is represented by two line segments that form an intersection.

The radius of the arc representing the inner surface 231 of the top portion 230 is referred to as the "fourth radius." In the first example configuration, the fourth radius is greater than 0 mm. In the second example configuration, the fourth radius is 0 mm. The fourth radius is selected so as to fall within the reference range for the fourth radius. An example of the reference range for the fourth radius is provided below.

The reference range in the first example is a range equal to or greater than the lower limit radius RD1. The reference range in the second example is a range equal to or less than the upper limit radius RD2. The reference range in the third example is a range equal to or greater than the lower limit radius RD1 and equal to or less than the upper limit radius RD2.
The lower limit radius RD1 is selected from, for example, 0.0 mm, 0.2 mm, and 0.3 mm, and the upper limit radius RD2 is selected from, for example, 1.5 mm, 1.0 mm, and 0.5 mm.

Please refer to Fig. 11. Fig. 11 shows an enlarged view of the restricting portion 220. A straight line parallel to the radial direction of the gate insert 100 in the reference cross section is referred to as a "reference line LL."
The configuration of the first side surface 221A of the restricting portion 220 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Fig. 11 shows the configuration of Example 1.

The configuration of the first example is the same as the configuration exemplified in the first embodiment. The portion of the restricting portion 220 corresponding to the first side surface 221A has a taper. In the reference cross section, the first side surface 221A of the restricting portion 220 is inclined with respect to the reference line LL.
The configuration of the second example is different from the configuration illustrated in the first embodiment. The portion of the restricting portion 220 corresponding to the first side surface 221A does not have a taper. In the reference cross section, the first side surface 221A of the restricting portion 220 is perpendicular to the reference line LL.

The angle indicating the inclination of the first side surface 221A of the restricting portion 220 with respect to the radial direction of the gate insert 100 is referred to as the “first angle TA.” In the reference cross section, the first angle TA is the angle between the first side surface 221A and the reference line LL.
In a first example configuration, the first angle TA is greater than 0°. In a second example configuration, the first angle TA is 90°. The first angle TA is selected to be included in a reference range for the first angle TA. The reference range for the first angle TA will now be illustrated.

The reference range in the first example is the range equal to or greater than the lower limit angle TA1. The reference range in the second example is the range equal to or less than the upper limit angle TA2. The reference range in the third example is the range equal to or greater than the lower limit angle TA1 and equal to or less than the upper limit angle TA2.
The lower limit angle TA1 is selected from, for example, 30°, 40°, or 50°, and the upper limit angle TA2 is selected from, for example, 90°, 80°, or 70°.

The configuration of the second side surface 221B of the restricting portion 220 in the second embodiment is selected from, for example, the configuration of Example 1 or the configuration of Example 2. Fig. 11 shows the configuration of Example 1.
The configuration of the first example is the same as the configuration exemplified in the first embodiment. The portion of the restricting portion 220 corresponding to the second side surface 221B has a taper. In the reference cross section, the second side surface 221B of the restricting portion 220 is inclined with respect to the reference line LL.

The configuration of the second example differs from the configuration illustrated in the first embodiment. The portion of the restricting portion 220 corresponding to the second side surface 221B does not have a taper. In the reference cross section, the second side surface 221B of the restricting portion 220 is parallel to the reference line LL.

The angle indicating the inclination of the second side surface 221B of the restriction portion 220 is referred to as the "second angle TB." In the reference cross section, the second angle TB is the angle formed between the second side surface 221B and the reference line LL.
In the first example configuration, the second angle TB is greater than 0°. In the second example configuration, the second angle TB is 0°. The second angle TB is selected so as to be included in a reference range for the second angle TB. The reference range for the second angle TB will now be illustrated.

The reference range in the first example is the range equal to or greater than the lower limit angle TB1. The reference range in the second example is the range equal to or less than the upper limit angle TB2. The reference range in the third example is the range equal to or greater than the lower limit angle TB1 and equal to or less than the upper limit angle TB2.
The lower limit angle TB1 is selected from, for example, 0.0°, 0.5°, or 1.0°, and the upper limit angle TB2 is selected from, for example, 60°, 40°, or 20°.

(Third embodiment)
The third embodiment is configured based on the first or second embodiment. In the third embodiment, an example of dimensions related to the gate insert 100 is presented.
Referring to Figure 12, the dimensions of the gate insert 100 in the radial direction of the gate insert 100 will be illustrated.

The center of the intermediate surface 221C of the restricting portion 220 is referred to as the "intermediate surface center." If the intermediate surface 221C of the restricting portion 220 is a curved surface, the intermediate surface center is the circumferential center of the arc that represents the intermediate surface 221C of the restricting portion 220. If the intermediate surface 221C of the restricting portion 220 includes two flat surfaces, the intermediate surface center is the intersection of two line segments that represent the intermediate surface 221C of the restricting portion 220.

The center of the connection surface 221D of the restriction portion 220 is referred to as the "connection surface center." If the connection surface 221D of the restriction portion 220 is a curved surface, the connection surface center is the center of the circumference of the arc that represents the connection surface 221D of the restriction portion 220. If the connection surface 221D of the restriction portion 220 includes two flat surfaces, the connection surface center is the intersection of the two line segments that represent the connection surface 221D of the restriction portion 220.

The distance between the gate center axis LC and the center of the mid-surface in the radial direction of the gate insert 100 is referred to as the "first radial distance RY1." The distance between the center of the mid-surface and the center of the connecting surface in the radial direction of the gate insert 100 is referred to as the "second radial distance RY2." The sum of the first radial distance RY1 and the second radial distance RY2 is referred to as the "third radial distance RY3."

The ratio of the first radial distance RY1 to the third radial distance RY3 is referred to as the "radial ratio RR." The radial ratio RR is selected so that it falls within a reference range for the radial ratio RR. An example of the reference range for the radial ratio RR is shown below.

The reference range in the first example is a range equal to or greater than the lower limit ratio RR1. The reference range in the second example is a range equal to or less than the upper limit ratio RR2. The reference range in the third example is a range equal to or greater than the lower limit ratio RR1 and equal to or less than the upper limit ratio RR2.
The lower limit ratio RR1 is selected from, for example, 5.0%, 6.0%, or 7.0%, and the upper limit ratio RR2 is selected from, for example, 50%, 30%, or 15%.

Referring to Figure 12, the dimensions of the gate insert 100 in the axial direction of the gate insert 100 will be illustrated.
In the reference cross section, the intersection of the line segment LR3 indicating the top surface of the basic solid of the protrusion space S12 and the gate central axis LC is referred to as the "first intersection HA." In the reference cross section, the intersection of the reference line LL passing through the center of the midplane and the gate central axis LC is referred to as the "second intersection HB." In the reference cross section, the intersection of the curve LQ1 indicating the hemispherical surface of the basic solid of the bottom space S11 and the gate central axis LC is referred to as the "third intersection HC."

The distance between the first intersection point HA and the second intersection point HB in the axial direction is referred to as the "first axial distance HX1." The distance between the second intersection point HB and the third intersection point HC in the axial direction is referred to as the "second axial distance HX2." The combined distance of the first axial distance HX1 and the second axial distance HX2 is referred to as the "third axial distance HX3."

The ratio of the first axial distance HX1 to the third axial distance HX3 is referred to as the "axial ratio HR." The axial ratio HR is selected so that it falls within a reference range for the axial ratio HR. An example of the reference range for the axial ratio HR is shown below.

The reference range in the first example is a range equal to or greater than the lower limit ratio HR1. The reference range in the second example is a range equal to or less than the upper limit ratio HR2. The reference range in the third example is a range equal to or greater than the lower limit ratio HR1 and equal to or less than the upper limit ratio HR2.
The lower limit ratio HR1 is selected from, for example, 8.0%, 9.0%, or 10%, and the upper limit ratio HR2 is selected from, for example, 50%, 40%, or 30%.

The third axial distance HX3 is selected so as to be included in a reference range for the third axial distance HX3. The reference range for the third axial distance HX3 will be exemplified below.
The reference range in the first example is a range equal to or greater than the lower limit distance HXA, the reference range in the second example is a range equal to or less than the upper limit distance HXB, and the reference range in the third example is a range equal to or greater than the lower limit distance HXA and equal to or less than the upper limit distance HXB.
The lower limit distance HXA is selected from, for example, 0.5 mm, 1.0 mm, and 1.5 mm, and the upper limit distance HXB is selected from, for example, 5.0 mm, 4.0 mm, and 3.0 mm.

(Fourth embodiment)
The fourth embodiment is configured based on the first to third embodiments. In the fourth embodiment, an example of dimensions related to the gate insert 100 is presented.

The reference range for the first radius is determined, for example, as follows: The lower limit radius RA1 is 0.5 mm The upper limit radius RA2 is 5.0 mm The first radius range is a range equal to or greater than 0.5 mm and equal to or less than 5.0 mm.
The reference range for the second radius is determined, for example, as follows: The lower limit radius RB1 is 0.0 mm The upper limit radius RB2 is 2.0 mm The second radius range is a range equal to or greater than 0.0 mm and equal to or less than 2.0 mm.

The reference range for the third radius is determined, for example, as follows: The lower limit radius RC1 is 0.0 mm The upper limit radius RC2 is 1.5 mm The third radius range is a range equal to or greater than 0.0 mm and equal to or less than 1.5 mm.
The reference range for the fourth radius is determined, for example, as follows: The lower limit radius RD1 is 0.0 mm The upper limit radius RD2 is 1.5 mm The fourth radius range is a range equal to or greater than 0.0 mm and equal to or less than 1.5 mm.

The reference range for the first angle TA is determined, for example, as follows: The lower limit angle TA1 is 30° The upper limit angle TA2 is 90°.
The reference range for the second angle TB is determined, for example, as follows: The lower limit angle TB1 is 0.0°, and the upper limit angle TB2 is 60°.

The ranges for the radial ratio RR are determined, for example, as follows: The lower limit ratio RR1 is 5.0% The upper limit ratio RR2 is 50%.
The reference range for the axial ratio HR is determined, for example, as follows: The lower limit ratio HR1 is 8.0%, and the upper limit ratio HR2 is 50%.
The reference range for the third axial distance HX3 is determined, for example, as follows: The lower limit distance HXA is 0.5 mm The upper limit distance HXB is 5 mm.

Fifth Embodiment
The fifth embodiment is configured on the premise of any one of the first to fourth embodiments. In the fifth embodiment, an example of dimensions related to the gate clearance 122 is presented.

Refer to Figure 9. Regarding the state of the injection molding die 10, the state in which the central axis of the flow path 120A of the gate land 120 coincides with the central axis of the valve stem 24 is referred to as the "reference state of the injection molding die 10." The size of the gate clearance 122 in the reference state of the injection molding die 10 is referred to as the "clearance distance CL."

In the reference cross section, the clearance distance CL is the length of a reference line LL connecting the inner surface 121 of the gate land 120 and the outer peripheral surface 24B of the tip portion 24A of the valve stem 24.
The clearance distance CL is selected so as to fall within a reference range for the clearance distance CL. An example of the reference range for the clearance distance CL will be given below.

The reference range in the first example is a range equal to or greater than the lower limit distance CL1. The reference range in the second example is a range equal to or less than the upper limit distance CL2. The reference range in the third example is a range equal to or greater than the lower limit distance CL1 and equal to or less than the upper limit distance CL2.
The lower limit distance CL1 is selected from, for example, 0.005 mm, 0.010 mm, and 0.015 mm, and the upper limit distance CL2 is selected from, for example, 0.040 mm, 0.035 mm, and 0.030 mm.

Sixth Embodiment
The sixth embodiment is configured based on the fifth embodiment. In the sixth embodiment, an example of dimensions related to the gate insert 100 and the valve stem 24 is presented.

In a first example, the dimensions are selected as follows: The inner diameter of the flow path 120A of the gate land 120 is, for example, 3.42 mm. The outer diameter of the tip portion 24A of the valve stem 24 is, for example, 3.40 mm. The clearance distance CL is, for example, 0.010 mm.
In the second example, the dimensions are selected as follows: The flow channel inner diameter RE is, for example, 3.44 mm. The stem outer diameter RF is, for example, 3.40 mm. The clearance distance CL is, for example, 0.020 mm.

Seventh Embodiment
The seventh embodiment is based on any one of the first to sixth embodiments. The gate insert 100 of the seventh embodiment differs from the first to sixth embodiments in the configuration of the protrusion forming portion 200. The protrusion forming portion 200 can have the configuration of the following first or second example, for example.

In the first example, the basic solid corresponding to the protrusion space S12 of the protrusion forming portion 200 is a frustum of a sphere. The diameter of the basic solid decreases in the X1 direction.
In the second example, the basic solid corresponding to the protrusion space S12 is a cylinder. The shape of the cylinder is a truncated cone. The outer diameter of the basic solid decreases in the X1 direction.

Eighth Embodiment
The eighth embodiment is configured based on any one of the first to seventh embodiments. The gate insert 100 of the eighth embodiment differs from the first to seventh embodiments in the configuration of the protrusion forming portion 200. The change in the configuration of the protrusion forming portion 200 is reflected in the shape of the preform P10.
The protrusion forming portion 200 can have the following first or second example configuration, for example.

In the first example, the protrusion forming portion 200 includes a base portion 210 and a restricting portion 220. The restricting portion 220 is provided in the middle of the base portion 210 in the axial direction of the gate insert 100. The base portion 210 includes a portion located in the X1 direction relative to the restricting portion 220 and a portion located in the X2 direction relative to the restricting portion 220.

The following are examples of the position of the restricting portion 220 in the axial direction of the gate insert 100. In the first example, the center of the restricting portion 220 in the axial direction of the gate insert 100 is the same as the center of the base portion 210. In the second example, the restricting portion 220 is located closer to the gate land 120 than the center of the base portion 210. In the third example, the restricting portion 220 is located closer to the bottom molding portion 140 than the center of the base portion 210.

The inner surface 221 of the restricting portion 220 includes a second connecting surface. The second connecting surface is configured in accordance with the connecting surface 221D of the restricting portion 220 in the previous embodiment. The second connecting surface of the restricting portion 220 is located between the first side surface 221A of the restricting portion 220 and the inner surface 211 of the base portion 210. The second connecting surface of the restricting portion 220 is connected to the first side surface 221A of the restricting portion 220 and the inner surface 211 of the base portion 210.
The second connecting surface of the restricting portion 220 is a curved surface. In the reference cross section, the second connecting surface of the restricting portion 220 is represented by an arc. The center of the arc is determined in the protrusion space S12.

In the second example, the protrusion molding portion 200 includes a base portion 210, a restricting portion 220, and a bottom portion. The restricting portion 220 is located in the X2 direction relative to the base portion 210. The restricting portion 220 is located closer to the bottom molding portion 140 in the axial direction of the gate insert 100. The inner surface 221 of the restricting portion 220 includes a second connection surface.

The bottom is configured similarly to the top 230. The bottom includes an inner surface. The inner surface of the bottom forms part of the inner surface 201 of the protrusion molding portion 200. The inner surface of the bottom does not overlap the side surface of the basic solid. The inner surface of the bottom is located radially inward from the side surface of the basic solid.
The inner surface of the bottom is located between the second side surface 221B of the restricting portion 220 and the inner surface 141 of the bottom molding portion 140. The inner surface of the bottom is connected to the second side surface 221B of the restricting portion 220 and the inner surface 141 of the bottom molding portion 140.
The inner surface of the bottom is a curved surface. In the reference cross section, the inner surface of the bottom is represented by a circular arc. The center of the circular arc is determined in the protrusion space S12 or the bottom space S11.

Ninth embodiment
The ninth embodiment is configured based on any one of the first to eighth embodiments. The gate insert 100 of the ninth embodiment differs from the first to eighth embodiments in the configuration of the protrusion forming portion 200. The change in the configuration of the protrusion forming portion 200 is reflected in the shape of the preform P10.

The restricting portion 220 is configured to protrude from the base solid body. The restricting portion 220 is configured to be recessed outward in the radial direction of the gate insert 100 from the base portion 210.
The inner surface 221 of the restricting portion 220 is located radially outward from the side surface of the basic solid body. The inner surface 221 of the restricting portion 220 is configured to be recessed radially outward from the inner surface 211 of the base portion 210.

Tenth embodiment
The tenth embodiment is configured based on any one of the first to ninth embodiments. The gate insert 100 of the tenth embodiment differs from the first to ninth embodiments in the configuration of the protrusion forming portion 200. The change in the configuration of the protrusion forming portion 200 is reflected in the shape of the preform P10.
The protrusion forming portion 200 includes a plurality of restriction portions 220. The plurality of restriction portions 220 are provided at intervals in the axial direction of the gate insert 100.

Eleventh Embodiment
The eleventh embodiment is configured based on any one of the first to tenth embodiments. The gate insert 100 of the eleventh embodiment differs from the first to tenth embodiments in the configuration of the protrusion forming portion 200. The change in the configuration of the protrusion forming portion 200 is reflected in the shape of the preform P10.
The protrusion forming portion 200 includes a plurality of restriction portions 220. The restriction portions 220 are provided around the gate central axis LC at intervals. The length of each restriction portion 220 in the circumferential direction is shorter than the circumference.

Twelfth Embodiment
The twelfth embodiment is configured based on any one of the first to twelfth embodiments. The protrusion P200 of the preform P10 of the twelfth embodiment is a long gate. The gate insert 100 of the twelfth embodiment differs from the gate insert 100 of the first to twelfth embodiments in the configuration of the protrusion forming portion 200.

The protrusion forming portion 200 of the gate insert 100 of the twelfth embodiment is configured in accordance with the protrusion forming portion 200 of the prerequisite embodiment so as to be able to form the protrusion P200 of the long gate.
The manufacturing method of the preform P10 includes a molding step and a cutting step. The cutting step is performed after the molding step. In the cutting step, the protrusions P200 of the preform P10 are cut. The cut portion of the protrusions P200 is, for example, the middle portion of the base portion P210 of the protrusions P200.

When the protrusion P200 is cut, the portion of the protrusion P200 located in the X1 direction relative to the cut surface is separated from the preform P10. The portion of the protrusion P200 located in the X2 direction relative to the cut surface remains in the preform P10.

Thirteenth Embodiment
The thirteenth embodiment is configured based on any one of the first to thirteenth embodiments. The preform P10 of the thirteenth embodiment has a layered structure. The preform P10 includes a plurality of components stacked in the radial direction of the preform P10. In one example, the preform P10 includes an inner layer and an outer layer.

(effect)
The effects obtained by the gate insert 100, the fixing unit 40, and the manufacturing method of the preform P10 will be exemplified.

The likelihood of molding defects occurring in the main body P100 of the preform P10 and the life of the gate insert 100 are related to, for example, the clearance distance CL.
The larger the clearance distance CL, the less likely the tip 24A of the valve stem 24 will come into contact with the inner surface 121 of the gate land 120. The inner surface 121 of the gate land 120 will be less susceptible to wear. The life of the gate insert 100 will be extended. The gate insert 100 will need to be replaced less frequently. The running costs associated with the injection molding die 10 will be reduced.

The smaller the clearance distance CL, the less resin material remains in the gate clearance 122. This makes it more difficult for cold slug C to form in the gate clearance 122.

In one example of the gate insert 100, the first radius is greater than or equal to the lower limit radius RA1.
According to the above-described configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the first radius is less than or equal to the upper radius RA2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the second radius is greater than or equal to the lower limit radius RB1.
According to the above configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200. Sinks are less likely to be formed on the protrusions P200 of the preform P10.

In one example of the gate insert 100, the second radius is less than or equal to the upper radius RB2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the third radius is greater than or equal to the lower limit radius RC1.
According to the above-described configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the third radius is less than or equal to the upper limit radius RC2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the fourth radius is equal to or greater than the lower limit radius RD1.
According to the above-described configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the fourth radius is less than or equal to the upper radius RD2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the first angle TA is greater than or equal to the lower limit angle TA1.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained.

In one example of the gate insert 100, the first angle TA is less than or equal to the upper limit angle TA2.
According to the above-described configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the second angle TB is greater than or equal to the lower limit angle TB1.
According to the above-described configuration, for example, the following effects can be obtained: The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the second angle TB is less than or equal to the upper limit angle TB2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the radial ratio RR is equal to or greater than the lower limit ratio RR1.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained.

In one example of the gate insert 100, the radial ratio RR is equal to or less than the upper limit ratio RR2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained.

In one example of the gate insert 100, the axial ratio HR is equal to or greater than the lower limit ratio HR1.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained.

In one example of the gate insert 100, the axial ratio HR is equal to or less than the upper limit ratio HR2.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained.

In one example of the gate insert 100, the third axial distance HX3 is greater than or equal to the lower limit distance HXA.
According to the above configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slag C can be easily obtained. Whitening of the main body P100 of the preform P10 is less likely to occur. The quality of the appearance of the preform P10 is less likely to deteriorate.

In one example of the gate insert 100, the third axial distance HX3 is less than or equal to the upper limit distance HXB.
According to the above-described configuration, for example, the following effects can be obtained: The effect of preventing the movement of the cold slug C can be easily obtained. The protrusions P200 of the preform P10 can be easily separated from the protrusion forming portion 200.

In one example of the gate insert 100, the clearance distance CL is equal to or greater than the lower limit distance CL1.
According to the above configuration, the inner surface 121 of the gate land 120 and the outer peripheral surface 24B of the tip portion 24A of the valve stem 24 are less likely to wear.

In one example of the gate insert 100, the clearance distance CL is equal to or less than the upper limit distance CL2.
The above configuration provides the following advantages, for example: Cold slug C is less likely to be formed in the gate clearance 122; Cold slug C is less likely to remain in the gate clearance 122 for a long period of time; Burrs are less likely to be formed on the protrusions P200 of the preform P10.

Note that the possible forms of the gate insert, fixing unit, and preform manufacturing method of the present invention are not limited to those described in the above embodiments. The gate insert, fixing unit, and preform manufacturing method of the present invention may take forms different from those exemplified in the embodiments. Examples include forms in which part of the configuration of each embodiment is replaced, modified, or omitted, or forms in which new configurations are added to each embodiment.

40: Fixing unit 100: Gate insert 120: Gate land 200: Protrusion forming portion 210: Base portion 220: Restriction portion 221A: First side surface 221B: Second side surface 221C: Intermediate surface P10: Preform P110: Bottom portion P200: Protrusion

Claims (9)

A gate insert of a fixed unit for molding a preform, comprising:
a protrusion molding portion corresponding to the protrusion on the bottom of the preform;
The protrusion molding portion includes a restriction portion configured to prevent movement of the cold slug,
The restricting portion is configured to protrude from the base portion of the protrusion forming portion.
Gate insert. The gate insert according to claim 1 , wherein the restriction portion is configured to extend around the central axis of the gate insert. The gate insert according to claim 1 or 2, wherein the restriction portion is provided closer to the gate land in a direction parallel to the central axis of the gate insert. the restricting portion includes a first side surface, a second side surface, and an intermediate surface;
the first side surface is located between the intermediate surface and the gate land;
The gate insert according to any one of claims 1 to 3, wherein the second side surface is located between the intermediate surface and the base portion. the intermediate surface is a curved surface;
The gate insert according to claim 4, wherein the radius of the arc representing the intermediate surface is in the range of 2 mm or less. The gate insert according to claim 4 or 5, wherein an angle indicating an inclination of the first side surface relative to a radial direction of the gate insert is in a range of 30° or more. The gate insert according to any one of claims 4 to 6, wherein an angle indicating an inclination of the first side surface relative to a radial direction of the gate insert is in a range of 90° or less. A fixing unit comprising a gate insert according to any one of claims 1 to 7. A method for manufacturing a preform, comprising: molding a preform using the fixing unit according to claim 8.