JP7419945B2 - Mold release resistance evaluation device - Google Patents

Description

The present invention relates to a mold release resistance evaluation device.

BACKGROUND ART A mold release resistance evaluation device is known that evaluates mold release resistance by measuring the load generated when a molded product such as a casting is released from a mold. For example, Patent Document 1 includes a pin screwed into a casting mold using a mounting bolt and a load measuring device installed on the mounting bolt, and when the casting is released from the mold using the load measuring device. A mold release resistance evaluation device is disclosed that evaluates mold release resistance by measuring the load applied to the pins.

Japanese Patent Application Publication No. 2018-103237

The inventor evaluated the mold release resistance using a mold release resistance evaluation device that is arranged so that the mold body and the core fit together, and that includes a load acquisition unit in a connecting member that connects the mold body and the core. It has been found that the following problems occur when doing so. In other words, if the inner surface of the mold body and the side surface of the core are in contact with each other in the direction of releasing the molded product, when the molded product is released, the molded product, the core, and the mold body Frictional resistance occurs not only between the core and the mold body, but also at the contact area between the core and the mold body. Therefore, there is a problem in that it is difficult to accurately measure mold release resistance when releasing a molded product due to the influence of the contact.

The present invention was made in view of the above problems, and makes it possible to eliminate the influence of contact between the inner surface of the mold body and the side surface of the core in the direction of releasing the molded product when evaluating mold release resistance. The present invention provides a mold release resistance evaluation device.

The mold release resistance evaluation device according to the present invention includes:
A mold release resistance evaluation device that evaluates mold release resistance when a molded product is released from a mold,
a mold body having a recess;
a core including a convex portion shaped to fit into the concave portion and a flange portion disposed on the base side of the convex portion;
a connecting member that connects the inner bottom surface of the recess and the tip end surface of the convex portion;
a load acquisition unit disposed on the connecting member and capable of acquiring a load when the molded product is released from the mold;
The connecting member extends in a first direction extending in a direction in which the molded product is released from the mold body,
An inner surface of the concave portion extending in the first direction and a side surface of the convex portion extending in the first direction are connected to each other while being spaced apart from each other.

In the mold release resistance evaluation device according to the present invention, the connecting member extends in the first direction in which the molded product is released from the mold body, and extends in the first direction of the recess of the mold body. The inner surface of the core and the side surface of the convex portion of the core extending in the first direction are connected to each other while being spaced apart from each other. Therefore, the mold release resistance evaluation is based on the contact between the inner surface of the concave part of the mold body extending in the first direction and the side surface of the convex part of the core extending in the first direction in the direction of releasing the molded product. It is possible to provide a mold release resistance evaluation device that can eliminate the influence.

According to the present invention, mold release resistance evaluation is performed by contact between the inner surface extending in the first direction of the concave portion of the mold body and the side surface extending in the first direction of the convex portion of the core in the direction in which the molded product is released from the mold. It is possible to provide a mold release resistance evaluation device that can eliminate the influence on

FIG. 1 is a front sectional view showing a die-casting apparatus including a mold release resistance evaluation device according to an embodiment. FIG. 1 is a front sectional view showing a mold release resistance evaluation device according to an embodiment. FIG. 2 is a front sectional view showing a series of steps for evaluating mold release resistance when releasing a molded product from a die-casting device using the mold release resistance evaluation device according to the embodiment. It is a graph which shows the relationship between the load at the time of mold release acquired using the mold release resistance evaluation device based on an Example, and the occurrence of a crack of a rough material.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
Note that the right-handed xyz coordinates shown in the figure are for convenience in explaining the positional relationship of the constituent elements. Unless otherwise specified, the positive direction of the z-axis is vertically upward. Further, the xy plane is a horizontal plane.

<Embodiment>
FIG. 1 is a front sectional view showing a die-casting apparatus 1 including a mold release resistance evaluation device 10 according to the present embodiment. The mold release resistance evaluation apparatus 10 according to the present embodiment is an apparatus capable of evaluating mold release resistance when a molded product P molded using the die casting apparatus 1 is released from the mold body 11. In this embodiment, an example will be described in which the mold release resistance evaluation device 10 is installed in the die-casting device 1, but the present invention is not limited thereto. In addition, for example, the mold release resistance evaluation device can be installed and used in a casting device using a metal mold, a resin molding device using a mold for injection molding, extrusion molding, or the like.

First, the overall configuration of a die-casting apparatus 1 in which a mold release resistance evaluation device 10 according to the present embodiment is installed will be described using FIG. 1. FIG. 1 shows a die casting apparatus 1 before forming a molded product. As shown in FIG. 1, a die casting apparatus 1 according to the present embodiment includes a mold 2 and an injection device 3.

As shown in FIG. 1, the mold 2 includes a mold body 11 (hereinafter also referred to as the fixed mold 11) and movable molds 21a to 21c (hereinafter also referred to as the movable mold 21). The movable molds 21a to 21c can move together in the negative direction of the x-axis when the molds are opened. When releasing the molded product from the movable mold 21, the movable mold 21b can be further opened upward (positive direction of the z-axis), and the movable mold 21c can be further opened downward (negative direction of the z-axis).

As shown in FIG. 1, the fixed mold 11 includes a core 12 on the yz plane on the negative side of the x-axis. Furthermore, as shown in FIG. 1, the movable mold 21a may include a core 22 on the yz plane on the positive side of the x-axis. As shown in FIG. 1, when the movable mold 21a is also provided with a core 22, the core 12 and the core 22 can be used as one body when molding a molded product, and can be divided into parts that can be separated when releasing the mold. It is the middle child.

As shown in FIG. 1, the fixed mold 11 and the movable mold 21 are connected, and the core 12 and the core 22 are connected, and the fixed mold 11, the core 12, the core 22, and the movable mold 21 A cavity C, which is a hollow space into which the molten metal M flows, is formed.

As shown in FIG. 1, the fixed mold 11 further includes an injection device 3 on the positive side of the x-axis. The injection device 3 connected to the fixed mold 11 includes a sleeve 31 that contains the molten metal M, and a plunger 32 that injects the molten metal M into the cavity C so as to push it out. The die casting apparatus 1 is a casting apparatus that can form a molded product by cooling and solidifying the molten metal M injected into the cavity C from the injection device 3. The mold release resistance evaluation apparatus 10 according to the present embodiment is an apparatus that can evaluate the mold release resistance when a molded product molded in this manner is released from the fixed mold 11 and the core 12. The detailed configuration of the mold release resistance evaluation device 10 will be explained using FIG. 2.

FIG. 2 is a front sectional view showing the mold release resistance evaluation device 10 according to the present embodiment.
As shown in FIG. 2, the fixed mold 11 includes a recess 11a. Further, the core 12 includes a convex portion 12a, a base portion 12b, and a flange portion 13. In this specification, of the configuration of the core 12, a portion that fits into the shape of the recess 11a is referred to as a convex portion 12a (on the x-axis positive side from the broken line), and a portion that includes the flange portion 13 (indicated by a dashed line) is referred to as a convex portion 12a. It is called a base 12b (on the negative side of the x-axis from the broken line).

As shown in FIG. 2, the depth d of the recess 11a in the x-axis direction and the length d of the protrusion 12a in the x-axis direction are formed to match. In other words, the convex portion 12a of the core 12 is formed in a shape that fits into the concave portion 11a of the fixed mold 11. For example, when the shape of the concave portion 11a is cylindrical, the shape of the convex portion 12a can also be made cylindrical. Similarly, when the recessed portion 11a has a prismatic shape, the convex portion 12a can also have a prismatic shape.

As shown in FIG. 2, the connecting member 14 is a member that connects the inner bottom surface 11b of the concave portion 11a of the fixed mold 11 and the protruding end surface 12c of the convex portion 12a of the core 12. As the connecting member 14, for example, a bolt as shown in FIG. 2 can be used. The connecting member 14 extends in a first direction (x-axis direction) extending in a direction in which the molded product is released from the fixed mold 11 and the core 12 (x-axis negative direction). It is preferable that at least two connecting members 14 are provided. The arrangement of each connecting member 14 is uniform with respect to the shape of the inner bottom surface 11b of the recess 11a, from the viewpoint of stably connecting the fixed mold 11 and the core 12 to prevent wobbling or rattling. It is preferable to place the

As shown in FIG. 2, the fixed mold 11 and the core 12 connected by the connecting member 14 are connected to the inner surface extending in the first direction (x-axis direction) of the recess 11a of the fixed mold 11, and the core 12 connected by the connecting member 14. The side surfaces of the convex portion 12a included in the convex portion 12a extending in the first direction (x-axis direction) are connected to each other while being spaced apart from each other. On the other hand, the yz plane of the flange portion 13 included in the base portion 12b is connected to the fixed mold 11 while being in contact with the same.

That is, as shown in FIG. 2, the fixed mold 11 and the core 12 are connected with a gap g in the first direction (x-axis direction), while the flange contacting the fixed mold 11 By providing the portion 13 in the core 12, it is possible to suppress the molten metal M from entering the gap g during casting.

The width of the gap g (in the z-axis direction) is preferably such that the fixed mold 11 and the core 12 can be kept separated from each other. More specifically, the gap g is defined by the convex portion 12a of the core 12 when a load is applied to the fixed mold 11 and the core 12 when the molded product is released from the mold. It is preferable that the width is such that the side surfaces of the mold 11 do not come into contact with the inner surface of the recess 11a of the fixed mold 11.

As shown in FIG. 2, the connecting member 14 includes a load acquisition section 15. The load acquisition unit 15 is a member that can acquire the load, strain, etc. when the molded product is released from the mold. As the load acquisition unit 15, for example, a strain gauge, a load cell, a piezoelectric sensor, etc. can be used. For example, as shown in FIG. 2, when a bolt is used as the connecting member 14 and a strain gauge is used as the load acquisition section 15, the strain gauge can be disposed so as to be embedded in the center of the bolt. Further, as the load acquisition section 15, a plate-shaped and cylindrical load cell or a piezoelectric sensor can also be used. The load cell or piezoelectric sensor can be installed like a washer on the head side (x-axis positive side) of the bolt when fastening the bolt.

As shown in FIG. 2, the load acquisition section 15 is connected to a measuring instrument 16. Using the acquired data, the measuring device 16 can evaluate the mold release resistance when the molded product is released from the mold. As the measuring instrument 16, for example, a measuring computer or the like can be used. A series of steps for evaluating mold release resistance will be described later using FIG. 3.

Note that when assembling the fixed mold 11 and the core 12, they may be connected by the connecting member 14 after using a knock pin (not shown) that can improve positioning accuracy. For example, as shown in FIG. 2, the inner bottom surface 11b of the fixed mold 11 is arranged so that it extends in the same first direction (x-axis direction) as the first direction (x-axis direction) in which the connecting member 14 extends. A through hole TH penetrating up to the point can be provided. Further, the protruding end surface 12c of the core 12 can be provided with a dowel hole 12d to which a dowel pin is connected. Note that if a dowel pin is not used when assembling the fixed mold 11 and the core 12, the through hole TH and the dowel hole 12d may not be provided.

As shown in FIG. 2, it is preferable to provide at least two through holes TH in order to accurately position the fixed mold 11 and the core 12. Further, from the viewpoint of increasing the accuracy of positioning, it is preferable that the through holes TH are arranged evenly with respect to the shape of the inner bottom surface 11b of the recess 11a. After the fixed mold 11 and the core 12 are connected, the knock pin can be removed before the load acquisition unit 15 acquires the load at the time of releasing the molded product.

FIG. 3 is a front sectional view showing a series of steps for evaluating the mold release resistance when releasing the molded product P from the die casting apparatus 1 using the mold release resistance evaluation apparatus 10 according to the present embodiment. .
FIG. 3 shows a state in which, after molding the molded product P, the movable molds 21a to 21c are moved in the opening direction (in the negative direction of the x-axis, indicated by black arrows), and the molded product P is released from the fixed mold 11. . In this embodiment, the molded product is molded with a release agent sprayed on the surface of the mold 2 in advance. A load acquisition unit 15 disposed on the connecting member 14 acquires the load generated when the molded product P is demolded, and a measuring device 16 evaluates the demolding resistance based on the acquired data.

The measuring device 16 can control the equipment 17 by transmitting control data created based on the evaluation of the mold release resistance to the equipment 17. The equipment 17 is, for example, equipment that adjusts the amount of mold release agent, equipment that supplies cooling water for cooling the mold 2, and the like. The equipment 17 can be controlled based on the evaluation of mold release resistance by the measuring device 16. For example, if the measured load during mold release, that is, the mold release resistance is large, the amount of mold release agent can be increased, and if the mold release resistance is small, the amount of mold release agent can be controlled to be decreased. . For example, the results of the evaluation of mold release resistance include the selection of the type of mold release agent, adjustment of the amount of cooling water passed through the cooling pipe that passes through the mold (adjustment of mold temperature), and the type of surface treatment of the mold. It can be used for selecting the mold, adjusting the surface roughness of the mold, adjusting the slope of the surface shape of the core, examining die time (time required for solidification), etc.

The inventor evaluated the mold release resistance using a mold release resistance evaluation device that is arranged so that the mold body and the core fit together, and that includes a load acquisition unit in a connecting member that connects the mold body and the core. It has been found that the following problems occur when doing so. In other words, if the inner surface of the mold body and the side surface of the core are in contact with each other in the direction in which the molded product is to be released, when the molded product is released, the molded product, the core, and the mold body will be damaged. Frictional resistance occurs not only between the core and the mold body, but also at the contact area between the core and the mold body. Therefore, there is a problem in that it is difficult to accurately measure mold release resistance when releasing a molded product due to the influence of the contact.

In contrast, in the mold release resistance evaluation device according to the present embodiment, the connecting member extends in the first direction in which the molded product is released from the mold body, and the connecting member extends in the first direction in the direction in which the molded product is released from the mold body. The inner surface extending in the first direction and the side surface of the convex portion of the core extending in the first direction are connected to each other while being spaced apart from each other. Therefore, the mold release resistance evaluation is based on the contact between the inner surface of the concave part of the mold body extending in the first direction and the side surface of the convex part of the core extending in the first direction in the direction of releasing the molded product. It is possible to obtain the load at the time of mold release of a molded product while eliminating the influence, that is, frictional resistance. Therefore, the mold release resistance evaluation device according to this embodiment can measure mold release resistance more accurately and perform quantitative evaluation.

The mold release resistance evaluation device according to this embodiment can quantitatively evaluate mold release resistance. Therefore, the results of the evaluation of mold release resistance can be used to, for example, adjust the amount of mold release agent, select the type of mold release agent, adjust the amount of cooling water passed through the cooling pipe passing through the mold (adjust mold temperature), It can be used to select the type of surface treatment of the mold, adjust the surface roughness of the mold, adjust the gradient of the surface shape of the core, examine the die time (time required for solidification), etc. Therefore, the results of mold release resistance evaluation can be utilized for checking the quality of casting conditions and for manufacturing control.

Furthermore, when assembling the fixed mold and the core, if the knock pins are used to position them and connect them, it is possible to prevent the z-axis negative side of the convex portion from being connected in a tilted state due to gravity. In this embodiment, the dowel pin can be removed before obtaining the load at the time of mold release. For example, if the demolding resistance is evaluated with the dowel pin installed, the load applied to the core during demolding is transmitted not only to the bolt but also to the dowel pin, which affects the evaluation of the demolding resistance. In contrast, in the mold release resistance evaluation device according to the present embodiment, the mold release resistance transmitted to the knock pin can be eliminated by removing the knock pin. In this way, when the fixed mold and core are assembled after positioning using dowel pins, the gap g formed between the inner surface of the recess and the side surface of the convex portion is It is possible to connect the fixed mold and the core so that it is more uniform throughout. Therefore, the fixed mold and the core can be connected with higher precision without affecting the mold release resistance.

Hereinafter, the present invention will be specifically explained based on Examples with reference to FIG. 4, but the present invention is not limited to these Examples.

The mold release resistance evaluation device used in this example is in a state in which the inner surface of the recess of the fixed mold extending in the first direction and the side surface of the protrusion of the core extending in the first direction are separated from each other. (See Figure 2). Therefore, it is possible to obtain the load at the time of mold release of the molded product while eliminating frictional resistance due to contact between the concave portion and the convex portion. Therefore, quantitative evaluation of mold release resistance is possible. On the other hand, as a comparative example, the mold release resistance was evaluated in a state where the inner surface of the recess of the fixed mold, which extends in the first direction, and the side surface of the convex part of the core, which extends in the first direction, were in contact with each other. The mold release load was measured using the device. Note that the molded product in this example is also referred to as "raw material". "Rough material" refers to a finished product in a casting or forging process, and is an intermediate molded product before being processed into a product.

In this example, as an example, the conditions of both the amount of spraying of the mold release agent and the amount of cooling water passed through the cooling pipe passing inside the mold were changed, and the load at the time of mold release was obtained when the conditions were changed. The amount of mold release agent sprayed and the amount of cooling water were each changed in three stages (small amount, medium amount, and large amount), and the load when the rough material was released from the mold was measured.

First, a comparative example will be explained. When the load at the time of mold release was obtained using the mold release resistance evaluation device according to the comparative example, even when the conditions were changed as described above, there was no significant difference in the load at the time of mold release of the obtained raw material. Sometimes it did not occur. This is thought to be because frictional resistance occurred at the contact portion between the inner surface of the recess and the side surface of the convex portion during mold release, and the load during mold release could not be accurately measured due to the influence of the frictional resistance.

Next, examples will be described. FIG. 4 is a graph showing the relationship between the load during mold release and the occurrence of cracks in the rough material, which was obtained using the mold release resistance evaluation device according to the example. The horizontal axis of the graph in FIG. 4 shows the load at the time of demolding, and the vertical axis shows the number of rough materials.

In the example, as shown in the graph of FIG. 4, when the conditions of both the amount of mold release agent sprayed and the amount of cooling water passed through the cooling pipe passing inside the mold were changed, the mold release time obtained was The results showed that there was a difference in the load between the two. More specifically, regarding each condition of the amount of mold release agent sprayed and the amount of cooling water, the larger the amount of mold release agent and cooling water, the lower the load during mold release, and the smaller the amount, the lower the load during mold release. We were able to obtain the result that the load at the time was high.

This is considered to be because when the amount of mold release agent decreased, the frictional resistance between the mold and the raw material increased. Furthermore, when the amount of cooling water decreases, the mold is not sufficiently cooled and the temperature of the mold increases. This makes it difficult for the mold release agent to adhere to the surface of the mold, causing galling. In addition, when the mold temperature is high, the adhesion between the mold and the rough material increases, resulting in a part of the rough material remaining in the mold and causing the surface of the rough material to peel off. obtain. Therefore, it is considered that the load at the time of mold release was increased.

In this way, even if there is a difference in the load at the time of mold release due to a change in conditions, the mold release resistance evaluation device according to this example eliminates the influence of frictional resistance and calculates the load at the time of mold release. We were able to obtain it quantitatively.

Furthermore, in this example, it was observed whether cracks occurred in the raw material at each load when the raw material was released from the mold. In the graph of FIG. 4, after being released from the mold, the rough material in which no cracks occurred is indicated by diagonal lines going upward to the right, and the rough material in which cracks occurred is indicated by diagonal lines descending to the right. Regarding the loads A to I (horizontal axis) during mold release shown in FIG. 4, A indicates the lowest load and I indicates the highest load. The proportion of raw materials with cracks in the total number of materials is 0% under load A, 6% under load B, 13% under load C, 45% under load D, and 79% under load E. It was 91% for load F, 93% for load G, and 100% for loads H and I. Thus, in this example, it was found that there is a correlation between the load during demolding of the rough material and the occurrence of cracks. In other words, it was possible to obtain the results that the lower the load during demolding, the lower the rate of cracking, and the higher the load during demolding, the higher the rate of cracking.

Furthermore, for example, when the load is high among the loads A to I, the amount of cooling water used to cool the mold is small. If the amount of cooling water is small, the mold may not be cooled sufficiently and the rough material may not be cooled properly. Therefore, the raw material becomes difficult to solidify, and the strength of the raw material itself may also decrease. Therefore, it is thought that the percentage of cracks that occurred was high.

As described above, the mold release resistance evaluation device according to this embodiment can evaluate the mold release resistance while eliminating the influence of contact between the inner surface of the mold body and the side surface of the core in the direction of mold release, that is, the frictional resistance. was able to evaluate. Therefore, the mold release resistance evaluation device according to this embodiment can quantitatively acquire the load during mold release when examining the conditions during mold release. Therefore, the mold release resistance evaluation device according to this embodiment can be utilized for examining conditions during mold release, confirming the quality of casting conditions, and manufacturing management.

Note that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit.

1 Die-casting device 10 Mold release resistance evaluation device 11 Mold body (fixed type)
11a Concave portion 11b Internal bottom surface 12 Core 12a Convex portion 12b Base portion 12c Tip end surface 13 Flange portion 14 Connecting member 15 Load acquisition portion 16 Measuring device 17 Equipment 21, 21a to 21c Movable mold 22 Core 31 Sleeve 32 Plunger C Cavity M Molten metal P Molding

Claims (1)

A mold release resistance evaluation device that evaluates mold release resistance when a molded product is released from a mold,
a mold body having a recess;
a core including a convex portion shaped to fit into the concave portion and a flange portion disposed on the base side of the convex portion;
a connecting member that connects the inner bottom surface of the recess and the tip end surface of the convex portion;
a load acquisition unit disposed on the connecting member and capable of acquiring a load when the molded product is released from the mold;
The connecting member extends in a first direction extending in a direction in which the molded product is released from the mold body,
An inner surface of the concave portion extending in the first direction and a side surface of the convex portion extending in the first direction are connected to each other while being spaced apart from each other.
Mold release resistance evaluation device.

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