JP7783113B2 - Injection molding machine, heat limiting member, and heat input suppression method - Google Patents

Description

This disclosure relates to an injection molding machine, a heat limiting member, and a heat input suppression method.

The mold unit installed in the injection molding machine is adjusted to the temperature required for the molded product by supplying and discharging a temperature-control medium through piping. The heat from the mold unit is transferred to the tie bars, for example, via the platens (fixed platen, movable platen), and affects the amount of elongation of the tie bars when clamping force is generated.

For this reason, Patent Document 1 proposes a structure that suppresses direct heat transfer from the platen to the tie bars by sandwiching a heat insulating material between the platen and the tie bars within the platen.

JP 2008-296384 A

However, it is difficult to select an insulating material that can withstand the load applied when the mold assembly is clamped and that also has a high insulating effect. Furthermore, during injection molding using an injection molding machine, the mold assembly and piping heat the air around them. In the injection molding machine disclosed in Patent Document 1, the tie bars extend from the platen in an exposed state. Therefore, the air heated by the mold assembly and piping directly enters the tie bars.

In particular, the amount of heat input to the four tie bars varies depending on the shape of the mold, the position of the piping, etc. This can cause the four tie bars to stretch unevenly, resulting in an unstable clamping force and potentially having a significant impact on the molding of the molded product.

This invention provides technology that can stabilize molding accuracy by preventing the tie bars from heating and stretching through the air.

One aspect of the present invention is an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen, on which a movable mold is installed, along tie bars relative to a fixed platen on which a fixed mold is installed, and that has a thermal restriction unit that restricts the movement of air heated to room temperature or higher around the tie bar to the tie bar.

Another aspect of the present invention is a thermal limiting member attached to an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen, on which a movable mold is installed, along tie bars relative to a fixed platen on which a fixed mold is installed. When attached to the tie bar, the thermal limiting member restricts air heated to a temperature above room temperature around the tie bar from moving toward the tie bar.

Another aspect of the present invention is a heat input suppression method for limiting heat input to tie bars in an injection molding machine in which a movable platen on which a movable mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold, thereby restricting air heated to a temperature above room temperature around the tie bars from moving toward the tie bars.

The injection molding machine, heat limiting member, and heat input suppression method of the present invention can stabilize molding accuracy by preventing the tie bars from heating and stretching through the air.

FIG. 2 is a diagram illustrating a state when mold opening of the injection molding machine according to the embodiment is completed. FIG. 2 is a diagram illustrating a state during mold clamping of the injection molding machine according to the embodiment. FIG. 2 is a diagram schematically illustrating the support side of a fixed mold in a mold clamping device. FIG. 10 illustrates the attachment of the thermal limiting portion to the tie bar. FIG. 10 is a diagram schematically illustrating a thermal limiting portion according to a modified example.

The following describes embodiments of the present disclosure with reference to the drawings. In each drawing, identical components are designated by the same reference numerals, and duplicate descriptions may be omitted.

(injection molding machine)
Fig. 1 is a diagram showing a state of an injection molding machine according to an embodiment when mold opening is completed. Fig. 2 is a diagram showing a state of an injection molding machine according to an embodiment when mold clamping is performed. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction represent horizontal directions, and the Z-axis direction represents vertical directions. When the mold clamping device 100 is of a horizontal type, the X-axis direction is the mold opening/closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side of the Y-axis direction is called the operating side, and the positive side of the Y-axis direction is called the counter-operating side.

As shown in Figures 1 and 2, the injection molding machine 10 includes a mold clamping unit 100 that opens and closes the mold apparatus 800, an ejector unit 200 that ejects molded products molded by the mold apparatus 800, an injection unit 300 that injects molding material into the mold apparatus 800, a movement unit 400 that moves the injection unit 300 forward and backward relative to the mold apparatus 800, a control unit 700 that controls each component of the injection molding machine 10, and a frame 900 that supports each component of the injection molding machine 10. The frame 900 includes a mold clamping unit frame 910 that supports the mold clamping unit 100 and an injection unit frame 920 that supports the injection unit 300. The mold clamping unit frame 910 and the injection unit frame 920 are each installed on the floor 2 via leveling adjusters 930. The control unit 700 is located in the interior space of the injection unit frame 920. Each component of the injection molding machine 10 will be described below.

(mold clamping device)
In the description of the mold clamping device 100, the direction of movement of the movable platen 120 during mold closing (e.g., the positive X-axis direction) is defined as the front, and the direction of movement of the movable platen 120 during mold opening (e.g., the negative X-axis direction) is defined as the rear.

The mold clamping device 100 closes, pressurizes, clamps, releases pressure, and opens the mold of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

The mold clamping unit 100 is, for example, a horizontal type, and the mold opening and closing direction is horizontal. The mold clamping unit 100 has a fixed platen 110 to which the fixed mold 810 is attached, a movable platen 120 to which the movable mold 820 is attached, and a movement mechanism 102 that moves the movable platen 120 in the mold opening and closing direction relative to the fixed platen 110.

The stationary platen 110 is fixed to the mold clamping unit frame 910. The stationary mold 810 is attached to the surface of the stationary platen 110 facing the movable platen 120.

The movable platen 120 is arranged so that it can move freely in the mold opening and closing direction relative to the mold clamping unit frame 910. A guide 101 that guides the movable platen 120 is installed on the mold clamping unit frame 910. A movable mold 820 is attached to the surface of the movable platen 120 facing the fixed platen 110.

The movement mechanism 102 moves the movable platen 120 forward and backward relative to the fixed platen 110 to perform mold closing, pressurization, mold clamping, depressurization, and mold opening of the mold device 800. The movement mechanism 102 includes a toggle support 130 spaced apart from the fixed platen 110, tie bars 140 connecting the fixed platen 110 and the toggle support 130, a toggle mechanism 150 that moves the movable platen 120 in the mold opening/closing direction relative to the toggle support 130, a mold clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the mold clamping motor 160 into linear motion, and a mold thickness adjustment mechanism 180 that adjusts the distance between the fixed platen 110 and the toggle support 130.

The toggle support 130 is disposed at a distance from the fixed platen 110 and is mounted on the mold clamping unit frame 910 so that it can move freely in the mold opening and closing direction. The toggle support 130 may also be disposed so that it can move freely along a guide laid on the mold clamping unit frame 910. The guide for the toggle support 130 may be the same as the guide 101 for the movable platen 120.

In this embodiment, the fixed platen 110 is fixed to the mold clamping unit frame 910, and the toggle support 130 is arranged so as to be movable relative to the mold clamping unit frame 910 in the mold opening/closing direction; however, the toggle support 130 may be fixed to the mold clamping unit frame 910, and the fixed platen 110 may be arranged so as to be movable relative to the mold clamping unit frame 910 in the mold opening/closing direction.

The tie bars 140 connect the fixed platen 110 and the toggle support 130 at a distance L in the mold opening/closing direction. A total of four tie bars 140 are provided at each of the four corners of the fixed platen 110. There is no particular limit to the number of tie bars 140 that can be provided, as long as one or more are provided.

The four tie bars 140 are arranged parallel to the mold opening/closing direction and extend in response to the mold clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects strain in the tie bar 140. The tie bar strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the tie bar strain detector 141 is used to detect the mold clamping force, etc.

In this embodiment, a tie bar strain detector 141 is used as the clamping force detector that detects the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitance type, a hydraulic type, an electromagnetic type, or the like, and its attachment position is not limited to the tie bar 140.

The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130 and moves the movable platen 120 relative to the toggle support 130 in the mold opening/closing direction. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening/closing direction and a pair of link groups that bend and extend with the movement of the crosshead 151. Each of the pair of link groups has a first link 152 and a second link 153 that are connected to bendable and extendable by pins or the like. The first link 152 is attached to the movable platen 120 by a pin or the like so that it can swing freely. The second link 153 is attached to the toggle support 130 by a pin or the like so that it can swing freely. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 moves back and forth relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 moves back and forth relative to the toggle support 130.

Note that the configuration of the toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, while each link group has five nodes in Figures 1 and 2, it may have four, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold clamping motor 160 moves the crosshead 151 back and forth relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153 and moving the movable platen 120 back and forth relative to the toggle support 130. The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may also be connected to the motion conversion mechanism 170 via a belt, pulley, etc.

The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The mold clamping unit 100 performs processes such as mold closing, pressure increase, mold clamping, depressurization, and mold opening under the control of the control device 700.

During the mold closing process, the mold clamping motor 160 is driven to advance the crosshead 151 at a set movement speed to the mold closing completion position, thereby advancing the movable platen 120 and bringing the movable mold 820 into contact with the fixed mold 810. The position and movement speed of the crosshead 151 are detected, for example, using the mold clamping motor encoder 161. The mold clamping motor encoder 161 detects the rotation of the mold clamping motor 160 and sends a signal indicating the detection result to the control device 700.

The crosshead position detector that detects the position of the crosshead 151 and the crosshead movement speed detector that detects the movement speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, and general types can be used. The movable platen position detector that detects the position of the movable platen 120 and the movable platen movement speed detector that detects the movement speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, and general types can be used.

During the pressure increase process, the mold clamping motor 160 is further driven to move the crosshead 151 further forward from the mold closing completion position to the mold clamping position, thereby generating a mold clamping force.

In the mold clamping process, the mold clamping motor 160 is driven to maintain the position of the crosshead 151 at the mold clamping position. In the mold clamping process, the mold clamping force generated in the pressure increase process is maintained. In the mold clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection unit 300 fills the cavity space 801 with liquid molding material. The filled molding material solidifies to obtain a molded product.

The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products are obtained simultaneously. An insert material may be placed in part of the cavity space 801, and another part of the cavity space 801 may be filled with molding material. A molded product is obtained in which the insert material and molding material are integrated.

In the depressurization process, the mold clamping motor 160 is driven to move the crosshead 151 back from the mold clamping position to the mold opening start position, thereby moving the movable platen 120 back and reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

In the mold opening process, the mold clamping motor 160 is driven to move the crosshead 151 back at a set movement speed from the mold opening start position to the mold opening completion position, thereby retracting the movable platen 120 and separating the movable mold 820 from the fixed mold 810. The ejector unit 200 then ejects the molded product from the movable mold 820.

The setting conditions for the mold closing process, pressure increase process, and mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 during the mold closing process and pressure increase process (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from rear to front, and represent the start and end points of the section for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not need to be set. Only one of the mold clamping position and the mold clamping force may be set.

Setting conditions for the depressurization process and mold opening process are also set in a similar manner. For example, the movement speed and position of the crosshead 151 during the depressurization process and mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from front to rear, and represent the start and end points of the section for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. A movement speed switching position does not have to be set. The mold opening start position and mold closing completion position may be the same position. Furthermore, the mold opening completion position and mold closing start position may be the same position.

Instead of the movement speed and position of the crosshead 151, the movement speed and position of the movable platen 120 may be set. Furthermore, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

The toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. This amplification ratio is also called the toggle ratio. The toggle ratio changes depending on the angle θ between the first link 152 and the second link 153 (hereinafter referred to as the "link angle θ"). The link angle θ is determined from the position of the crosshead 151. When the link angle θ is 180°, the toggle ratio is maximum.

If the thickness of the mold device 800 changes due to replacement of the mold device 800 or a temperature change in the mold device 800, mold thickness adjustment is performed so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

The mold clamping unit 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. The mold thickness adjustment is performed, for example, between the end of a molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 has, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 that is rotatably but immovably held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is threaded onto the screw shaft 181.

A screw shaft 181 and a screw nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to multiple screw nuts 182 via a rotational driving force transmission unit 185. The multiple screw nuts 182 can be rotated synchronously. Note that by changing the transmission path of the rotational driving force transmission unit 185, it is also possible to rotate the multiple screw nuts 182 individually.

The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, a driven gear is formed on the outer periphery of each screw nut 182, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may also be composed of a belt, pulleys, etc. instead of gears.

The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Note that multiple mold thickness adjustment mechanisms may be used in combination.

The gap L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position of the toggle support 130 and the gap L. Note that the toggle support position detector that detects the position of the toggle support 130 and the gap detector that detects the gap L are not limited to the mold thickness adjustment motor encoder 184, and general types can be used.

The mold clamping unit 100 may have a mold temperature regulator that adjusts the temperature of the mold device 800. The mold device 800 has a flow path for a temperature control medium inside. The mold temperature regulator adjusts the temperature of the temperature control medium supplied to the flow path of the mold device 800, thereby adjusting the temperature of the mold device 800.

Note that the mold clamping unit 100 of this embodiment is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

The mold clamping unit 100 of this embodiment has a mold clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the mold clamping motor 160. The mold clamping unit 100 may also have a linear motor for mold opening and closing, and an electromagnet for mold clamping.

(Ejector device)
In describing the ejector device 200, similar to the description of the mold clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (e.g., the positive direction of the X-axis) is defined as the front, and the direction of movement of the movable platen 120 when the mold is opened (e.g., the negative direction of the X-axis) is defined as the rear.

The ejector unit 200 is attached to the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector unit 200 has an ejector rod 210 that ejects the molded product from the mold device 800, and a drive mechanism 220 that moves the ejector rod 210 in the movement direction of the movable platen 120 (X-axis direction).

The ejector rod 210 is arranged in a through hole in the movable platen 120 so that it can move back and forth freely. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The ejector unit 200 performs the ejection process under the control of the control unit 700. During the ejection process, the ejector rod 210 advances from the standby position to the ejection position at a set movement speed, thereby advancing the ejector plate 826 and ejecting the molded product. The ejector motor is then driven to retract the ejector rod 210 at the set movement speed, and the ejector plate 826 is retracted to its original standby position.

The position and movement speed of the ejector rod 210 are detected, for example, using an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Note that the ejector rod position detector that detects the position of the ejector rod 210 and the ejector rod movement speed detector that detects the movement speed of the ejector rod 210 are not limited to an ejector motor encoder, and general types can be used.

(injection device)
In the description of the injection unit 300, unlike the descriptions of the mold clamping unit 100 and the ejector unit 200, the movement direction of the screw 330 during filling (e.g., the negative X-axis direction) is described as the forward direction, and the movement direction of the screw 330 during metering (e.g., the positive X-axis direction) is described as the rearward direction.

The injection unit 300 is mounted on a slide base 301, which is arranged so that it can move forward and backward relative to the injection unit frame 920. The injection unit 300 is arranged so that it can move forward and backward relative to the mold unit 800. The injection unit 300 touches the mold unit 800 and fills the cavity space 801 inside the mold unit 800 with molding material. The injection unit 300 includes, for example, a cylinder 310 that heats the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 that is arranged so that it can move forward and backward and rotate within the cylinder 310, a metering motor 340 that rotates the screw 330, an injection motor 350 that moves the screw 330 forward and backward, and a load detector 360 that detects the load transmitted between the injection motor 350 and the screw 330.

Cylinder 310 heats the molding material supplied to it through supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, in pellet form and supplied to supply port 311 in a solid state. Supply port 311 is formed at the rear of cylinder 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer periphery of the rear of cylinder 310. A first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer periphery of cylinder 310, ahead of cooler 312.

The cylinder 310 is divided into multiple zones in the axial direction of the cylinder 310 (e.g., the X-axis direction). A first heater 313 and a first temperature detector 314 are provided in each of the multiple zones. A set temperature is set for each of the multiple zones, and the control device 700 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

The nozzle 320 is provided at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer periphery of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 becomes the set temperature.

The screw 330 is positioned within the cylinder 310 so that it can rotate freely and move forward and backward. When the screw 330 is rotated, the molding material is sent forward along the spiral groove of the screw 330. As the molding material is sent forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is sent forward to the front of the screw 330 and accumulates in the front part of the cylinder 310, the screw 330 is moved backward. When the screw 330 is then moved forward, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

A backflow prevention ring 331 is attached to the front of the screw 330 and can move back and forth as a backflow prevention valve to prevent the molding material from flowing back from the front to the rear of the screw 330 when the screw 330 is pushed forward.

When the screw 330 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and moves back relative to the screw 330 to a blocking position (see Figure 2) where it blocks the flow path of the molding material. This prevents molding material accumulated in front of the screw 330 from flowing backward.

On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material being sent forward along the spiral groove of the screw 330, and moves forward relative to the screw 330 to an open position (see Figure 1) where it opens the flow path of the molding material. This allows the molding material to be sent forward of the screw 330.

The backflow prevention ring 331 may be either a co-rotating type that rotates with the screw 330, or a non-co-rotating type that does not rotate with the screw 330.

The injection device 300 may also have a drive source that moves the backflow prevention ring 331 back and forth between the open position and the closed position relative to the screw 330.

The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340 and may be, for example, a hydraulic pump.

The injection motor 350 advances and retreats the screw 330. A motion conversion mechanism that converts the rotational motion of the injection motor 350 into linear motion of the screw 330 is provided between the injection motor 350 and the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that threads onto the screw shaft. A ball or roller may be provided between the screw shaft and the screw nut. The drive source that advances and retreats the screw 330 is not limited to the injection motor 350, and may be, for example, a hydraulic cylinder.

The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted into pressure by the control device 700. The load detector 360 is provided in the load transmission path between the injection motor 350 and the screw 330, and detects the load acting on the load detector 360.

The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into pressure acting between the screw 330 and the molding material, and is used to control and monitor the pressure that the screw 330 receives from the molding material, the back pressure on the screw 330, and the pressure that the screw 330 acts on the molding material.

The pressure detector that detects the pressure of the molding material is not limited to the load detector 360, and a general detector can be used. For example, a nozzle pressure sensor or a mold internal pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The mold internal pressure sensor is installed inside the mold device 800.

The injection device 300 performs processes such as a metering process, a filling process, and a pressure holding process under the control of the control device 700. The filling process and pressure holding process may be collectively referred to as the injection process.

In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is sent forward along the spiral groove of the screw 330. As this happens, the molding material gradually melts. As the liquid molding material is sent forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. The rotational speed of the screw 330 is detected, for example, using the metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Note that the screw rotational speed detector that detects the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

During the metering process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit sudden retraction of the screw 330. The back pressure on the screw 330 is detected, for example, using a load detector 360. The metering process is completed when the screw 330 retracts to the metering completion position and a predetermined amount of molding material accumulates in front of the screw 330.

The position and rotational speed of the screw 330 during the metering process are set together as a series of setting conditions. For example, a metering start position, a rotational speed switching position, and a metering completion position are set. These positions are arranged in this order from front to rear, and represent the start and end points of the section for which the rotational speed is set. The rotational speed is set for each section. There may be one or more rotational speed switching positions. The rotational speed switching position does not have to be set. In addition, back pressure is set for each section.

In the filling process, the injection motor 350 is driven to advance the screw 330 at a set travel speed, filling the liquid molding material accumulated ahead of the screw 330 into the cavity space 801 in the mold device 800. The position and travel speed of the screw 330 are detected, for example, using the injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, a switch from the filling process to the pressure holding process (so-called V/P switch) occurs. The position at which the V/P switch occurs is also called the V/P switch position. The set travel speed of the screw 330 may be changed depending on the position of the screw 330, time, etc.

The position and movement speed of the screw 330 during the filling process are set together as a series of setting conditions. For example, a filling start position (also called the "injection start position"), a movement speed switching position, and a V/P switching position are set. These positions are arranged in this order from rear to front, and represent the start and end points of the section for which the movement speed is set. A movement speed is set for each section. There may be one or more movement speed switching positions. A movement speed switching position does not have to be set.

An upper limit for the pressure of the screw 330 is set for each section in which the movement speed of the screw 330 is set. The pressure of the screw 330 is detected by the load detector 360. When the pressure of the screw 330 is equal to or less than the set pressure, the screw 330 is advanced at the set movement speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, in order to protect the mold, the screw 330 is advanced at a movement speed slower than the set movement speed so that the pressure of the screw 330 remains equal to or less than the set pressure.

Note that after the screw 330 reaches the V/P switching position during the filling process, the screw 330 may be temporarily stopped at the V/P switching position, and then the V/P switching may be performed. Immediately before the V/P switching, instead of stopping the screw 330, the screw 330 may be slowly moved forward or backward. Furthermore, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, and general types can be used.

During the dwelling process, the injection motor 350 is driven to push the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") at a set pressure, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. This can replenish any molding material that is lacking due to cooling contraction within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed depending on factors such as the elapsed time from the start of the dwelling process. Multiple holding pressures and holding times for maintaining the holding pressure during the dwelling process may be set, or they may be set together as a series of setting conditions.

During the dwelling process, the molding material in the cavity space 801 inside the mold device 800 is gradually cooled, and when the dwelling process is completed, the entrance to the cavity space 801 is blocked with solidified molding material. This state is called a gate seal, and prevents the molding material from flowing back from the cavity space 801. After the dwelling process, the cooling process begins. During the cooling process, the molding material in the cavity space 801 is solidified. A weighing process may be carried out during the cooling process to shorten the molding cycle time.

In this embodiment, the injection device 300 is an in-line screw type, but it may also be a pre-plasticization type. A pre-plasticization type injection device supplies molding material molten in a plasticization cylinder to an injection cylinder, which then injects the molding material into a mold device. Within the plasticization cylinder, a screw is arranged so that it can rotate freely but cannot move back and forth, or the screw is arranged so that it can rotate freely and move back and forth. Meanwhile, within the injection cylinder, a plunger is arranged so that it can move back and forth.

In addition, the injection unit 300 of this embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, but it may also be a vertical type in which the axial direction of the cylinder 310 is vertical. The mold clamping unit combined with the vertical injection unit 300 may be either a vertical type or a horizontal type. Similarly, the mold clamping unit combined with the horizontal injection unit 300 may be either a horizontal type or a vertical type.

(Mobile device)
In describing the moving device 400, similar to the description of the injection device 300, the direction of movement of the screw 330 during filling (e.g., the negative X-axis direction) will be described as the forward direction, and the direction of movement of the screw 330 during metering (e.g., the positive X-axis direction) will be described as the rearward direction.

The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800, generating nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional pump that generates hydraulic pressure by drawing in hydraulic fluid (e.g., oil) from either the first port 411 or the second port 412 and discharging it from the other port by switching the rotation direction of the motor 420. The hydraulic pump 410 can also draw in hydraulic fluid from a tank and discharge it from either the first port 411 or the second port 412.

The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 with a rotational direction and rotational torque according to a control signal from the control device 700. The motor 420 may be an electric motor or an electric servo motor.

The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the interior of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via the first flow path 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby pushing the injection device 300 forward. The injection device 300 is moved forward, and the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure for the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second flow path 402. The hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, thereby pushing the injection unit 300 backward. The injection unit 300 is retracted, and the nozzle 320 is separated from the fixed mold 810.

In this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited to this. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into linear motion of the injection device 300 may be used.

(Control device)
The control device 700 is configured, for example, by a computer, and as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by causing the CPU 701 to execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside via the input interface 703 and transmits signals to the outside via the output interface 704.

The control device 700 repeatedly manufactures molded products by repeating processes such as the metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure holding process, cooling process, pressure release process, mold opening process, and ejection process. The series of operations required to obtain a molded product, for example, the operations from the start of a metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

One molding cycle includes, for example, a metering process, mold closing process, pressurization process, mold clamping process, filling process, pressure holding process, cooling process, depressurization process, mold opening process, and ejection process, in this order. The order here refers to the order in which each process starts. The filling process, pressure holding process, and cooling process are performed during the mold clamping process. The start of the mold clamping process may coincide with the start of the filling process. The completion of the depressurization process coincides with the start of the mold opening process.

In order to shorten the molding cycle time, multiple processes may be performed simultaneously. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be started during the mold closing process. The ejection process may also be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, the mold opening process may also be started during the metering process. This is because even if the mold opening process is started during the metering process, molding material will not leak from the nozzle 320 as long as the on-off valve closes the flow path of the nozzle 320.

Note that one molding cycle may include processes other than the metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure holding process, cooling process, depressurization process, mold opening process, and ejection process.

For example, after the dwelling step is completed and before the metering step begins, a pre-metering suck-back step may be performed in which the screw 330 is retracted to a preset metering start position. This can reduce the pressure of the molding material that has accumulated in front of the screw 330 before the metering step begins, and prevent the screw 330 from retracting suddenly at the start of the metering step.

Furthermore, after the metering process is completed and before the filling process begins, a post-metering suck-back process may be performed in which the screw 330 is retracted to a preset filling start position (also called the "injection start position"). This can reduce the pressure of the molding material that has accumulated in front of the screw 330 before the filling process begins, and prevent the molding material from leaking from the nozzle 320 before the filling process begins.

The control device 700 is connected to an operation device 750 that accepts user input operations and a display device 760 that displays a screen. The operation device 750 and display device 760 may be integrated, for example, and comprise a touch panel 770. The touch panel 770 serving as the display device 760 displays a screen under the control of the control device 700. The touch panel 770 screen may display information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10. The touch panel 770 screen may also display operation units such as buttons and input fields that accept user input operations. The touch panel 770 serving as the operation device 750 detects user input operations on the screen and outputs signals corresponding to the input operations to the control device 700. This allows, for example, a user to operate the operation units provided on the screen while checking the information displayed on the screen to perform settings for the injection molding machine 10 (including input of setting values). The user can also operate the operation units provided on the screen to cause the injection molding machine 10 to perform operations corresponding to the operation units. The operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the mold clamping unit 100, ejector unit 200, injection unit 300, movement unit 400, etc. The operation of the injection molding machine 10 may also be the switching of the screen displayed on the touch panel 770 serving as the display device 760, etc.

In this embodiment, the operation device 750 and display device 760 are described as being integrated as a touch panel 770, but they may also be provided independently. Furthermore, multiple operation devices 750 may be provided. The operation device 750 and display device 760 are disposed on the operation side (negative Y-axis direction) of the mold clamping unit 100 (more specifically, the fixed platen 110).

(Configuration of tie bar 140)
Next, the configuration of the tie bar 140 according to this embodiment will be described with reference to Figures 3 and 4. Figure 3 is a diagram schematically showing the support side of the fixed mold 810 in the mold clamping unit 100, where (A) is a cross-sectional view taken along line III-III in Figure 1 and (B) is a side view. Figure 4 is a diagram showing the attachment of the thermal limiting portion 142 to the tie bar 140, where (A) is a perspective view and (B) is a diagram showing the operation during attachment.

As described above, the mold clamping unit 100 of the injection molding machine 10 has four tie bars 140 extending between the fixed platen 110 and the toggle support 130 (see FIG. 1). Each of the four tie bars 140 is located at one of the four corners of the fixed platen 110 and one of the four corners of the toggle support 130. Each tie bar 140 is inserted into a hole in the fixed platen 110 and is firmly fixed by a fixing structure 146 on the back side of the fixed platen 110.

The tie bar 140 is formed, for example, in a circular shape with a predetermined diameter when viewed in a cross section perpendicular to the mold opening/closing direction. The tie bar 140 extends linearly while maintaining this diameter.

On the other hand, the movable platen 120 (see Figure 1) has through holes or notches (not shown) at its four corners to allow the tie bars 140 extending between the fixed platen 110 and the toggle support 130 to pass through.

The fixed mold 810 of the mold device 800 is provided in the center of the fixed platen 110 (between the four tie bars 140). The fixed mold 810 is positioned away from each tie bar 140 and is not in contact with them. Note that in a cross-sectional view perpendicular to the mold opening/closing direction (Figure 3(A)), the fixed mold 810 has a square shape, but it may be formed in other shapes, such as a rectangular shape that is elongated in the vertical or horizontal direction. Also, although not shown, the movable mold 820 of the mold device 800 is provided in the center of the movable platen 120 (between the four tie bars 140) so as to face the fixed mold 810.

The mold device 800 is equipped with a temperature control mechanism 811 that adjusts the temperature of the fixed mold 810. The temperature control mechanism 811 has a temperature control medium circulating device (not shown) and piping 812 (temperature control medium supply pipe 812a, temperature control medium discharge pipe 812b) that connects the temperature control medium circulating device and the fixed mold 810. The temperature control medium circulating device adjusts the temperature of the temperature control medium and circulates the temperature-adjusted temperature control medium through the fixed mold 810. The temperature control medium can be, for example, water, a liquid organic substance (oil, etc.), or a mixture of these. The mold device 800 may also be equipped with a temperature control mechanism for the movable mold 820 similar to the temperature control mechanism 811 for the fixed mold 810. The mold device 800 is not limited to a configuration that circulates a temperature control medium, and may also be equipped with a heater inside.

Each pipe 812 has an internal flow path through which a temperature control medium can flow. The temperature control medium supply pipe 812a supplies the temperature control medium from the temperature control medium circulation device to the fixed mold 810. The temperature control medium discharge pipe 812b returns the temperature control medium discharged from the fixed mold 810 to the temperature control medium circulation device. The pipes 812 are connected, for example, to the horizontal side surface of the fixed mold 810 and extend laterally (horizontally). In other words, the temperature control medium supply pipe 812a and the temperature control medium discharge pipe 812b pass between two tie bars 140 arranged above and below.

In the injection molding machine 10 configured as described above, the surrounding air is heated to above room temperature by the fixed mold 810, temperature control medium supply pipe 812a, and temperature control medium discharge pipe 812b. Heat generated by the fixed mold 810 is mainly due to the high-temperature resin filled into the fixed mold 810. Heat generated by the piping 812 is mainly due to the circulating temperature control medium. To prevent this heated air from moving toward the tie bar 140 (direct contact of the heated air with the tie bar 140), the injection molding machine 10 has a heat limiting section 142 around the tie bar 140.

The thermal limiting portion 142 is provided on the outer peripheral surface of the tie bar 140, which extends outside the fixed platen 110 and toggle support 130. The thermal limiting portion 142 in the illustrated example is in direct contact with the outer peripheral surface of the tie bar 140 and employs a thermal limiting member 143 that covers the entire circumferential circumference of the outer peripheral surface. Although not shown, the tie bar strain detector 141 is attached at an appropriate position on the tie bar 140 so that it is exposed from the thermal limiting member 143 that covers the tie bar 140.

The heat limiting member 143 is composed of an insulating material that can be wrapped around the outer periphery of the tie bar 140. Examples of insulating materials that can be used to make up the heat limiting member 143 include inorganic fibers such as glass wool, glass fiber, and ceramic fiber, or resin materials containing fibers or porous materials. The heat limiting member 143 may also have a layered structure in which multiple layers with different functions are stacked.

As shown in FIG. 4(A), the thermal limiting member 143 is formed in a cylindrical shape with an inner circumferential surface that roughly matches the outer circumferential surface of the tie bar 140. This thermal limiting member 143 may be configured to be elastically deformable to fit the outer diameter of the tie bar 140, or may be configured to be rigid enough to continuously maintain its cylindrical shape. Alternatively, the thermal limiting member 143 may be formed in a sheet shape and wrapped around the tie bar 140. The thermal limiting member 143 may have a seal structure (not shown) with an adhesive layer on one side that contacts the outer circumferential surface of the tie bar 140.

Also, as shown in FIG. 4(B), the thermal limiting member 143 may be provided with an attachment structure 144 that allows the user of the injection molding machine 10 to attach and detach the member, and may be removably attached to the tie bar 140. This allows the thermal limiting member 143 to be removed for work such as when installing the mold device 800 on the fixed platen 110 or the movable platen 120, improving workability. The attachment structure 144 may be configured, for example, with slits 144a formed at predetermined circumferential positions on the thermal limiting member 143 and connecting members 144b that connect the thermal limiting members 143 between the slits 144a. In other words, the thermal limiting member 143 may be configured as an elastic member that is formed with a C-shaped cross section across the slits 144a before installation and maintains that shape.

The heat limiting member 143 may be formed with a diameter slightly larger than the diameter of the outer circumferential surface of the tie bar 140, and its inner circumferential surface may form an air layer between it and the outer circumferential surface of the tie bar 140. The air layer may be space, or a member such as a porous body may be interposed. In other words, the heat limiting portion 142 may be structured so as to be out of contact (or partially in contact) with the outer circumferential surface of the tie bar 140.

The heat limiting portion 142 may also be constructed by coating the outer surface of the tie bar 140 with a heat insulating paint or heat reflective paint having a thermal conductivity lower than that of the tie bar 140.

The heat limiting portion 142 provided on the tie bar 140 has one end facing the fixed platen 110 in contact with the fixed platen 110 without any gaps. This ensures that the tie bar 140 is not exposed around the fixed mold 810. Note that one end of the heat limiting portion 142 may be partially inserted inside the fixed platen 110.

The heat limiting portion 142 is continuous and extends beyond the fixed mold 810, which protrudes from the fixed platen 110 toward the movable platen 120. The axial extent of the heat limiting portion 142 along the tie bar 140 is not particularly limited, but it is preferable that it be installed across the entire space between the fixed platen 110 and the movable platen 120. More specifically, the other end of the heat limiting portion 142 preferably reaches the movable platen 120, which is positioned at the mold closing start position. This ensures that the heat limiting portion 142 can reliably insulate the entire adjacent area between the fixed mold 810 and the movable mold 820 when the mold device 800 is in the mold clamping state. By appropriately adjusting the thickness of the heat limiting portion 142, it is possible to prevent the heat limiting portion 142 from contacting the corners that form the through-holes and notches in the movable platen 120. This prevents the heat limiting portion 142 from interfering with the mold closing and mold opening operations of the movable platen 120. The heat limiting portion 142 may be thinner at the portion that may come into contact with the movable platen 120 as the movable platen 120 moves, and thicker at the portion that does not come into contact with the movable platen 120 (such as a position near the fixed platen 110). The heat limiting portion 142 may also be provided over the entire area between the fixed platen 110 and the toggle support 130.

The injection molding machine 10 and heat limiting member 143 according to this embodiment are basically configured as described above, and their operation (heat input suppression method) and effects will be explained below.

Under the control of the control device 700, the injection molding machine 10 performs the following injection molding processes: metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure holding process, cooling process, depressurization process, mold opening process, and ejection process.

During injection molding, the mold device 800 also operates the temperature control mechanism 811 to control (heat) the temperature of the fixed mold 810 and the movable mold 820. For example, the temperature control mechanism 811 supplies a temperature control medium to the fixed mold 810 via a temperature control medium supply pipe 812a, and discharges the temperature control medium that has controlled the temperature of the fixed mold 810 via a temperature control medium discharge pipe 812b. The temperature-controlled mold device 800 (fixed mold 810) or the pipe 812 through which the temperature control medium flows heats the surrounding air to above room temperature and causes convection.

The four tie bars 140 extending adjacent to the mold assembly 800 are affected by this heat. In particular, because heated air flows upward, the heated air is directed toward the tie bar 140 located above the temperature control medium supply pipe 812a. If the heat limiting member 143 were not provided, the heat from the mold assembly 800 would affect the four tie bars 140 unevenly. As a result, differences in axial force (amount of elongation during mold clamping) would occur among the four tie bars 140.

The injection molding machine 10 according to this embodiment is equipped with a heat limiting portion 142 on each of the four tie bars 140 extending outside the fixed platen 110. These heat limiting portions 142 limit the transfer of heat from the air heated by the mold assembly 800 and piping 812 to the tie bars 140, thereby reducing the heat input to the tie bars 140. This enables the injection molding machine 10 to stabilize the axial force of the tie bars 140, enabling smooth clamping of the fixed mold 810 and movable mold 820.

In particular, by providing each heat limiting section 142 on each of the four tie bars 140, it is possible to easily accommodate the direction of air heat input, which varies depending on the shape of the fixed mold 810 and movable mold 820, the arrangement of the piping 812, etc. Furthermore, by suppressing heat transfer within each heat limiting section 142, the difference in the amount of heat input reaching each tie bar 140 is reduced. Therefore, the injection molding machine 10 is able to align the axial forces of the four tie bars 140 when clamping the mold for injection molding, allowing for more stable injection molding.

Furthermore, by using a heat limiting member 143 designed in advance to fit the outer circumferential surface of the tie bar 140 as the heat limiting unit 142, the injection molding machine 10 can simplify the attachment and detachment of the heat limiting unit 142 to the tie bar 140. Therefore, even when the heat limiting unit 142 is used, the mold device 800 can be attached and detached, and maintenance of the injection molding machine 10 can be performed efficiently. Furthermore, it is preferable that the heat limiting unit 142 be fixed to the tie bar 140 so that it does not stretch.

Furthermore, the thermal limiting portion 142 is provided continuously along the entire axial direction of the tie bar 140 from the fixed platen 110 to the movable platen 120, thereby suppressing the thermal effects of the mold device 800 over a sufficient axial length. At the same time, the tie bar 140 can be firmly fixed inside the fixed platen 110.

Furthermore, the heat limiting portion 142 arranged between the fixed mold 810 or the movable mold 820 and the tie bar 140 can stably limit the heat from the fixed mold 810 or the movable mold 820 from being transferred to the tie bar 140. Similarly, the heat limiting portion 142 arranged between the piping 812 and the tie bar 140 can stably limit the heat from the piping 812 from being transferred to the tie bar 140.

The injection molding machine 10 according to this embodiment is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, a configuration was described in which all four tie bars 140 were provided with heat limiting units 142. However, while the heat limiting units 142 may be provided on tie bars 140 that are more susceptible to the effects of heat, they may not be provided on tie bars 140 that are less susceptible to the effects of heat. For example, in Figure 3(A), the heat limiting unit 142 may be provided only on the upper left tie bar 140.

Figure 5 is a schematic diagram showing a thermal limiting unit according to a modified example. As shown in Figure 5, the injection molding machine 10 may be configured such that a shielding member 145 is disposed as the thermal limiting unit 142 between the mold assembly 800 and each tie bar 140. The shielding member 145 is formed, for example, in a plate shape and fixed to the fixed platen 110 or the like. Note that in Figure 5, the shielding member 145 is an arc-shaped plate, but the shape of the shielding member 145 is not limited thereto and may be, for example, a flat plate. In this way, even if the shielding member 145 is disposed at a position away from the outer circumferential surface of the tie bar 140 and between the mold assembly 800 and the piping 812, the injection molding machine 10 can restrict the movement of air heated by the mold assembly 800 to the tie bar 140.

The injection molding machine 10, thermal limiting member, and heat input suppression method according to the disclosed embodiments are illustrative in all respects and not restrictive. The embodiments may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above multiple embodiments may be configured differently and may be combined together, provided that they are not inconsistent.

10 Injection molding machine 110 Fixed platen 120 Movable platen 140 Tie bar 142 Heat limiting section 810 Fixed mold 820 Movable mold

Claims (6)

An injection molding machine in which a movable platen on which a fixed mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold,
a heat limiting portion that limits the movement of air heated to a temperature above room temperature around the tie bar to the tie bar;
the heat limiting unit has a shielding unit provided between the fixed mold or the movable mold and the tie bar, and exposes the tie bar to the outside on the opposite side of the shielding unit across the tie bar.
Injection molding machine. the heat limiting portion is provided on a portion of the tie bar that is exposed from the fixed platen.
2. The injection molding machine according to claim 1 . The heat limiting portion is disposed between the fixed mold or the movable mold and the tie bar.
3. The injection molding machine according to claim 1 or 2 . the heat limiting unit is disposed between the tie bar and a pipe that supplies and discharges a temperature control medium to and from the inside of the fixed mold or the movable mold.
4. The injection molding machine according to claim 1. A thermal limiting member attached to an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen, on which a fixed mold is installed, along tie bars relative to a fixed platen, on which a fixed mold is installed,
The thermal limiting member is
a shielding portion disposed between the fixed mold or the movable mold and the tie bar, and the tie bar is exposed to the outside on the opposite side of the shielding portion with the tie bar sandwiched therebetween;
When the air conditioner is attached to the tie bar, the air heated to a temperature equal to or higher than room temperature around the tie bar is restricted from moving to the tie bar.
Thermal limiting member. 1. A heat input suppression method for an injection molding machine in which a movable platen on which a fixed mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold, the method comprising:
a shielding part is disposed between the fixed mold or the movable mold and the tie bar, and a heat limiting part is attached on the opposite side of the tie bar from the shielding part, exposing the tie bar to the outside;
The heat limiting portion limits the movement of air heated to a temperature higher than room temperature around the tie bar to the tie bar.
Heat input suppression method.