JP2005271429A - Molding die device and molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die device and a molding method by which a required product accuracy can be ensured, and the molding cycle time can be shortened. <P>SOLUTION: This molding die device is equipped with a first die section comprising a core block 3 for molding a molded article surface required a high accuracy, and a second die section comprising a die 1 on a fixed side, a die 2 on a movable side, an ejector block 4, and sliding blocks 5 and 6 for molding molded article surfaces other than the first molded article surface. Then, the molding die device molds a molded article by filling a molding material in a molded article cavity 29. A temperature adjusting means 9 which forcibly cools the molded article only for a specified period of time through the core block 3 before both die sections are opened after the molding material is filled in the molded article cavity 29 is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molding die device and a molding method, and more particularly to a molding die device and a molding method applied when molding a molded product with strict dimensional accuracy.

  Examples of conventional molding die technology for molding a molded product that requires dimensional accuracy include, for example, a core pin (first die) for molding the inner peripheral surface of the main cylindrical portion that particularly requires dimensional accuracy, and the main cylindrical portion. An outer mold part (second mold) for molding the outer peripheral surface of the mold, and a molded product cavity defined between the core pin (first mold) and the outer mold part (second mold) In a mold apparatus that fills a molding material and molds a cylindrical molded product, the outer mold part (second mold) is separated from the outer peripheral surface of the cylindrical molded product through a pressure holding and cooling process from the injection process. Thereafter, in a state where the inner peripheral surface of the main cylindrical portion is held by the core pin (first mold), the low temperature medium is supplied from the temperature adjusting means to the first medium passage provided in the core pin (first mold), and the core pin The inner peripheral surface of the main cylindrical portion is forcibly cooled through the (first mold). In this way, the molding surface that requires dimensional accuracy after mold opening is configured to be locally forcibly cooled while being held in the first mold part. Deformation due to stress can be minimized, and high dimensional accuracy can be ensured (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2003-71842 (page 3, FIGS. 1 and 2)

  Since the conventional mold apparatus is configured as described above, it is possible to obtain a highly accurate molded product locally, but in order to forcibly cool the part that requires accuracy after mold opening, the mold is released from the mold opening. Time for forced cooling is required. Therefore, instead of obtaining a highly accurate molded product locally, it takes extra time for forced cooling. Although depending on the size, material, and shape of the molded product, generally, a long time is required for the cooling process in a series of molding processes. In the manufacturing process of molded products, particularly in the production of mass-produced products, an important issue is how fast the manufacturing cycle time can be achieved while ensuring the required product accuracy. In the conventional mold apparatus, the forced cooling time after the mold opening has been an impediment to shortening the cycle time.

  This invention has been made to solve the above-mentioned problems, and by devising the forced cooling timing, the cooling time is shortened and the entire molding cycle time is secured while ensuring the necessary product accuracy. It is an object of the present invention to obtain a molding die apparatus and a molding method that can shorten the process time.

  The molding die apparatus according to the present invention includes a first mold part for molding one molded product surface and a second mold part for molding the other molded product surface, and the first mold part. In a molding die apparatus for molding a molded product by filling a molding cavity with a molding material defined between the mold and the second mold part, both molds are filled with the molding material in the molding cavity. A temperature adjusting means for forcibly cooling the molded product through the first mold part for a predetermined time from before the part is opened is provided.

  Further, the molding method of the present invention is a molding defined between a first mold part for molding one molded product surface and a second mold part for molding the other molded product surface. In a molding method in which a molding material is molded by filling a molding cavity with a molding material, a predetermined time is passed through the first mold section before the mold parts are opened after the molding cavity is filled with the molding material. Only the molded product is forcibly cooled.

  According to the molding die apparatus of the present invention, after filling the molding cavity with the molding material, the molded product is forcibly cooled for a predetermined time through the first mold part before the mold parts are opened. Temperature adjustment means is provided, and the molded product is forcibly cooled through the first mold part, so that the amount of deformation due to thermal shrinkage and internal stress of the molded product after releasing the molded product is minimized. The molding cycle can be shortened.

  According to the molding method of the present invention, the molded product is forcibly cooled for a predetermined time through the first mold part after the mold material is filled with the molding material and before the mold parts are opened. Therefore, the molding cycle can be shortened while minimizing the amount of deformation due to thermal shrinkage and internal stress of the molded product after the molded product is released.

Embodiment 1 FIG.
Before explaining the invention of the first embodiment, the cause of the deformation of the molded product will be explained. There are mainly the following five causes for the deformation of the molded product in the molding process. The first cause is deformation due to coagulation shrinkage. This shrinks and deforms as the molding material undergoes a phase transformation from a molten state to a solidified state. The second cause is deformation due to heat shrinkage. In the molding, even after the molding material is solidified, it shrinks and deforms depending on the linear expansion coefficient inherent to the molding material as the temperature decreases to room temperature. The third cause is thermal stress. Due to the above-described solidification shrinkage and heat shrinkage, the molded product tends to shrink and deform, but the deformation is restrained by the molding die until it is released from the molding die. Thermal stress is generated. Then, after being released from the mold, the thermal stress is released to cause deformation. The fourth cause is crystal distortion. When the molding material undergoes a rapid phase transformation, crystallization is not sufficiently promoted, and distortion on the crystal structure occurs, thereby deforming the molded product. The fifth cause is deformation due to external force. When the molded product is not completely solidified, when the molded product is released from the mold, an external force is applied to the molded product to cause plastic deformation, and the deformation remains even after the external force is released.

  Therefore, if the occurrence of the above five causes can be controlled and suppressed as much as possible, deformation of the molded product can be suppressed even after the molded product is released from the molding die, and a highly accurate molded product is obtained. be able to. The present invention provides a molding die apparatus and a molding method for molding a molded product having a highly accurate molding surface by controlling and suppressing the occurrence of these five causes as much as possible.

  FIG. 1 is a conceptual diagram showing a molding die apparatus according to the first embodiment. Before describing the molding die, first, a molded product molded by the molding die exemplified here will be described. FIG. 4 is a view showing a molded product, which is made of, for example, polyphenylene sulfide resin (hereinafter abbreviated as PPS resin). (A) of a figure is a front view, (b) is a side view. As shown in the figure, the molded product 22 is composed of a base plate portion 23 and two support columns 24 and 25 perpendicular to the base plate portion 23. However, this shape is only an example, and the shape is not particularly limited as long as it is composed of a plurality of surfaces. Also, the molding material is not particularly limited to the PPS resin.

  The shape of the molded product 22 will be described in more detail. The two support columns 24 and 25 perpendicular to the inner surface of the base plate portion 23 are disposed so that the inner surfaces face each other with a predetermined distance therebetween. Moreover, each support | pillar part 24 and 25 is provided with the through-holes 24a and 25a. These two support columns 24 and 25 are the places where the highest accuracy is required, and in particular, high accuracy is required for the parallelism between the inner surfaces and the perpendicularity to the inner surface of the base plate portion 23. To do. That is, the 22a surface is a portion where high accuracy is required.

  Next, the structure of the molding die will be described with reference to FIG. The mold is composed of a fixed mold 1, a movable mold 2, and a plurality of blocks incorporated in the mold. The molding material is filled from the mold inlet 26 through the material flow path 27 to the molded product cavity 29 through the molded product cavity inlet 28. When this molding die is separated from the features of the invention of the present embodiment, a first mold part for molding a molded product surface that requires high accuracy and a second mold for molding all other molded product surfaces. It consists of a mold part. The first mold portion corresponds to the core block 3 and is a mold for molding the 22a surface of the molded product 22 described in FIG. The second mold part is a part for molding all other molded product surfaces. The fixed mold 1, the movable mold 2, and the two ejector blocks 4 incorporated in the mold 2 And slide blocks 5 and 6.

  The fixed-side mold 1 molds the 22b surface of the molded product 22. The ejector block 4 molds the 22c surface of the molded product 22. The slide block 5 forms the 22d surface of the molded product 22 and the through hole 24a of the support column 24. The slide block 6 molds the 22e surface of the molded product 22 and the through hole 25a of the support column 25. Further, although not shown in the drawings, the movable mold 2 molds the 22f surface and the 22g surface of the molded product 22. A space defined by a gap between the fixed mold 1, the movable mold 2, the core block 3, the ejector block 4, and the slide blocks 5 and 6 is a molded product cavity 29.

  Among the blocks of each mold, the core block 3 for molding the 22a surface that requires the highest accuracy, that is, the molding surface of the first mold part is processed with high accuracy. Further, on the side surface of the core block 3, a groove is processed in a portion that comes into contact with the ejector block 4 and the movable mold 2 to form a heat insulating layer 7. The heat insulating layer 7 is made of a phenol resin containing a cotton cloth having a very low thermal conductivity or a porous steel material containing a large number of pores, and the core block 3, the ejector block 4, the movable die 2, Between. However, the material is not limited to the above, and may be an air layer.

  Steel materials such as alloy tool steel for cold mold (SKD-11) and stainless steel (SUS-420, SUS-440) are used for the material of the mold components. Among these, it is preferable that the core block 3 for molding a high-precision portion is formed of a material having a higher thermal conductivity and a smaller heat capacity than other components, such as a copper alloy or an aluminum alloy. However, these materials are not limited to the above.

  A medium flow path for allowing a mold temperature adjusting medium to circulate inside each of the fixed mold 1, the movable mold 2, the core block 3, and the slide blocks 5 and 6 constituting the molding mold. 1A, 2A, 3A, 5A, 6A are provided. Of these medium flow paths, the core flow path 3A provided in the core block 3, that is, the first mold portion is referred to as a first medium flow path. The fixed-side mold 1, the movable-side mold 2, the slide blocks 5, 6 That is, the medium flow paths 1A, 2A, 5A, 6A provided in the second mold portion are referred to as second medium flow paths.

  First, the second medium flow path will be described. The medium flow paths 1A, 2A, 5A, 6A are connected to each other in series via the communication flow path 8, and are connected to the high temperature medium supply unit 10 of the temperature adjusting means 9. The communication channel 8 is configured flexibly so that each block can move. The second medium flow paths 1A, 2A, 5A, and 6A do not necessarily need to be connected in series with each other, and may be connected in parallel and connected to the high-temperature medium supply unit 10 or individually. 10 may be connected. Alternatively, a plurality of high-temperature medium supply units 10 may be prepared and each medium flow path may be provided individually.

In contrast, the first medium flow path 3A is independent of the second medium flow paths 1A, 2A, 5A, and 6A, and the high temperature medium supply unit 10 and the low temperature medium supply unit 11 are connected via the medium switching unit 12. And connected to. The medium switching unit 12 is an apparatus for alternatively connecting the high temperature medium supply unit 10 and the low temperature medium supply unit 11 to the first medium flow path 3A, and includes four valves 13 to 16. . Specifically, the first valve 13 provided in the high-temperature medium supply channel 17 extending from the high-temperature medium supply unit 10 to the first medium channel 3A, and the high-temperature medium supply unit 10 returns from the first medium channel 3A. The second valve 14 provided in the high-temperature medium return flow path 18, the third valve 15 provided in the low-temperature medium supply flow path 19 from the low-temperature medium supply unit 11 to the first medium flow path 3A, and the first medium flow path 3A The fourth valve 16 is provided in the low-temperature medium return flow path 20 that returns to the low-temperature medium supply unit 11. The first to fourth valves 13 to 16 operate so as to individually open and close the flow paths 17 to 20 based on a control signal from the medium switching control unit 21. The type of valve to be used is not limited. For example, a direct acting solenoid valve is suitable from the viewpoint of the speed of control response.
As described above, since the high temperature medium and the low temperature medium are switched and supplied to the first medium flow path 3A, the individual flow paths for the high temperature medium and the low temperature medium are provided in the core block 3. In comparison, a large cross-sectional area of the first medium flow path can be ensured, and heat exchange efficiency can be increased.

  Water that is excellent in heat exchange efficiency and easy to handle was applied as a medium to be circulated through the medium flow path. That is, the high temperature medium supply unit 10 adjusts and supplies the medium water to a predetermined high temperature state, and the low temperature medium supply unit 11 adjusts and supplies the medium water to a predetermined low temperature state. The medium is not necessarily limited to water, and a liquid such as ethylene glycol or various oils, or a gas such as saturated steam or heating steam may be applied.

In this embodiment, as will be described later, the temperature of the high-temperature medium is 423 K, and high-pressure water of about 2 kgf / cm ² or more is supplied. On the other hand, since the temperature of the low temperature medium is 293 K, it is not necessary to make the pressure particularly high, and is about 1 kgf / cm ² . As described above, when there is a pressure difference between the high temperature medium and the low temperature medium, when the first to fourth valves 13 to 16 are simultaneously switched, the high pressure high temperature medium flows backward to the low temperature medium supply channel 19. Things will happen. For this reason, when the medium supplied to the first medium flow path 3A is switched from the high-pressure high-temperature medium to the low-pressure low-temperature medium, the opening timing of the third valve 15 provided in the low-temperature medium supply flow path 19 is set to open / close the other valves. The timing is delayed by a predetermined time from the timing. Conversely, when the medium supplied to the first medium flow path 3A is switched from the low pressure low temperature medium to the high pressure high temperature medium, the opening timing of the first valve 13 provided in the high temperature medium supply flow path 17 is set to other valves. The opening / closing timing is delayed by a predetermined time. In this way, it is possible to prevent the high-pressure high-temperature medium from flowing back without using a directional control valve such as a check valve.

  If it is difficult to directly install the medium flow path 3A inside because the core block 3 is small, a material having excellent thermal conductivity, a heat pipe, or the like is installed instead, and the medium flow path 3A is installed at the root portion. You may adjust temperature indirectly by letting it pass. Further, without using a medium, for example, a heating element or a cooling element may be embedded in a metal portion such as the core block 3 or a heat transfer heater may be installed.

  Next, the operation will be described. FIG. 2 is an explanatory view showing a molding process of a molded product by the molding die apparatus of the first embodiment. FIG. 3 is a diagram showing a switching mode between the high temperature medium and the low temperature medium supplied to each medium flow path in the molding process of the molded product. Hereinafter, with reference to these drawings, a method for molding a molded product using the molding die of the present embodiment will be described.

  As shown in FIG. 3, the molding of the molded product is continuously performed by sequentially repeating the mold closing process → the filling process → the pressure holding process → the cooling process → the mold opening process → the mold releasing process to the first mold closing process. Molding is performed.

  First, as shown in FIG. 2 (a), the molds on the movable side are abutted against the mold 1 on the fixed side, thereby closing the molding dies. In conjunction with this operation, the core block 3, the ejector block 4, and the slide blocks 5 and 6 are disposed inside the molding die (mold closing process). At this stage, a high temperature medium is supplied to the first medium flow path 3A and the second medium flow paths 1A, 2A, 5A, and 6A, and each mold block is heated to a predetermined temperature. From this state, as shown in FIG. 2B, the molten molding material 30 is injected from the mold inlet 26. The temperature of the molding material 30 at this time is about 573 K in the case of PPS resin. The molding material 30 in the molten state is filled from the material flow path 27 through the molded product cavity inlet 28 into the molded product cavity 29 (filling process). Thereafter, the filled molding material 30 undergoes volumetric shrinkage with phase transformation, so that a predetermined pressure is continuously applied to the molding material 30 in order to compensate for the shrinkage (pressure holding process). Simultaneously with the completion of the filling process and the pressure holding process, the first medium flow path 3A is switched from the hot medium supplied so far to the cold medium, and forced cooling of the core block 3 is started. Next, the phase transformation is advanced and solidified until the filled molding material 30 can maintain the shape of the molded product cavity 29 (cooling process). Next, as shown in FIG. 2 (c), the movable die 2 is separated from the fixed die 1, and the slide blocks 5 and 6 are separated from the molded product 22 in conjunction with the operation (die opening process). ). Even at this stage, the low-temperature medium is circulated through the first medium flow path 3A. Next, as shown in FIG. 2D, the molded product 22 is released by projecting the 22c surface of the molded product 22 with the ejector block 4 (mold release process). At the same time, in order to raise the temperature of the core block 3 again, the low temperature medium is switched to the high temperature medium for the first medium flow path 3A. Thereafter, as shown in FIG. 2 (a), the movable mold 2 is brought into contact with the fixed mold 1 to close the molding dies, and the core block 3, the ejector block 4, and the slide. The blocks 5 and 6 are arranged inside the molding die (mold closing process). By sequentially repeating these processes, a molded product can be continuously produced.

  As described above, in the first medium flow path 3A, the low-temperature medium is circulated from the pressure holding process to the next mold closing process, and the high-temperature medium is circulated otherwise. A high temperature medium is circulated through the second medium flow paths 1A, 2A, 5A, and 6A in all processes. Next, specific temperature settings for these media will be described.

  The reason why the high-temperature medium is circulated in both the medium flow paths from the mold closing process to the end of the filling process is to ensure good fluidity of the molding material 30 when the molding material cavity 29 is filled with the molding material 30. To suppress the temperature drop of the molding material 30 as much as possible to improve the strength of the weld part (rejoining part) and to suppress the rapid temperature drop of the molding material 30 and promote the crystallization of the molding material 30. This is to suppress the generation of crystal distortion. Therefore, when the fluidity, weld strength, and crystal strain of this molding material are taken into consideration, it is desirable that the temperature of each constituent mold is as high as possible. However, if the temperature is too high, the molded product 22 and the material flow path 27 are not sufficiently cooled in the next cooling process, so that a problem occurs during the removal, and the flow path portion of the molding material is desired in the mold opening process. There is a problem that it is torn at a place where it does not, the outermost layer part of the molded product 22 peels off and remains on the mold surface, or the ejector block 4 damages the molded product 22 and breaks through in the worst case. Furthermore, the amount of decomposition gas generated from the molding material increases, which may promote corrosion of the molding die. Therefore, as the temperature at which these problems do not occur, when the molding material is PPS resin, the upper limit value of the temperature of the high temperature medium is set to about 423K.

  On the other hand, when a crystalline resin such as a PPS resin is applied, it is necessary to set a lower limit value in addition to the upper limit value described above. That is, in the case of a crystalline resin, there is a maximum crystallinity (saturation crystallinity) that crystallization does not proceed any further. If the crystallinity of the molded product does not reach this saturation crystallinity, the crystal distortion increases, which acts as an internal stress, causing a reduction in dimensional accuracy. The degree of crystallinity also depends on the cooling rate at the time of solidification from the molten state.For example, if the mold is rapidly cooled to the room temperature without heating the mold, the crystallization does not progress and reaches the saturation crystallinity. do not do. Therefore, in order to obtain a molded product with good dimensional accuracy, the crystallinity of the molded product needs to reach the saturation crystallinity during the molding process. In the case of PPS resin, the saturation crystallinity is reached at 403K or higher. However, in the case of an amorphous resin typified by PC resin, since it does not have a crystal structure, the lower limit value of the mold temperature is not particularly limited.

  For these reasons, when PPS resin is applied as the molding material, when the molding material 29 is filled with the molding material, both the first mold part and the second mold part are kept in the temperature range of 403 to 423K. It is preferable to keep it. Therefore, in the present embodiment, the high-temperature medium supply unit 10 supplies the first medium flow path 3A and the second medium flow paths 1A, 2A, 5A, and 6A so that the upper limit value of the temperature range is 423K. The temperature of the hot medium was 423K. Note that when a material other than the PPS resin is applied as the molding material, the optimum temperature range is also different, and needs to be changed as appropriate according to the above-described conditions.

  Next, the reason why the low temperature medium is supplied to the first medium flow path 3A during the pressure holding process and the mold releasing process will be described. The technology to ensure the accuracy of a specific molding surface is the method illustrated in the background art section, that is, after the mold is opened through the pressure-holding process and cooling process from the filling process, the molding surface that requires further precision is held in the mold. There is a method to forcibly cool it down. The method constrains a part that requires high dimensional accuracy with a mold, while allowing other parts that do not require relatively high dimensional accuracy to be released and free deformation thereof. It is intended to suppress deformation due to stress. However, even if the supply of the low-temperature medium to the first medium flow path 3A is started for forced cooling, the temperature of the medium is set to the molded product 22 because the molded product 22 is cooled via the core block 3. There is a time lag before being transmitted to. Therefore, in consideration of this time difference, if the low temperature medium is supplied before the mold opening process, the forced cooling time after the mold opening process can be shortened, and the molding cycle time can be shortened. Become. Therefore, in the present embodiment, when the filling process is finished, the core block 3 is forcibly cooled until the temperature becomes equal to or lower than the glass transition point of the molding material in the state shown in FIG. .

  If forced cooling is started in the state of FIG. 2 (b), the molded product contracts due to cooling, and thermal stress is generated because it is constrained by the mold, but if the molded product has a simple shape, There are few parts where deformation is constrained, and thermal stress is small. Therefore, even if forced cooling is performed before the mold opening process of the molded product, deformation of the molded product due to thermal stress can be small.

  The reason for cooling to below the glass transition point in the state of FIG. 2B is as follows. That is, when the temperature of the molded product is cooled from a temperature equal to or higher than the glass transition point to a temperature similar to room temperature, the deformation due to solidification shrinkage due to the phase transformation and the deformation due to thermal shrinkage depending on the linear expansion coefficient are added. Whereas the amount of deformation occurs, when the temperature of the molded product is cooled from a temperature below the glass transition point to a temperature similar to room temperature, only deformation due to thermal shrinkage depending on the linear expansion coefficient is obtained. In addition, when the molded product is released from the mold, if the temperature of the molded product is equal to or higher than the glass transition point, the molded product is not completely solidified and deforms when an external force is applied to the molded product along with the mold release. . Therefore, the surface requiring accuracy is cooled to just before the mold release and brought as close to room temperature as possible, and the other surfaces are forcibly cooled so as to be at least below the glass transition point. The glass transition point of the PPS resin applied in this embodiment is about 363K. Therefore, the temperature of the low temperature medium is set to 293 K so that the molded product 22 can be cooled to room temperature as much as possible before the mold release process.

The time for forced cooling is determined by the time required for cooling the surface 22a, which is the surface in contact with the core block 3, in the molded product 22 to a desired temperature. In the present embodiment in which the PPS resin that is a crystalline resin is applied, as an example, when the length of the molded product 22 is about several centimeters, the temperatures of the support columns 24 and 25 and the base plate portion 23 are below the glass transition point. The time required for cooling is approximately 10 seconds or more. Since it takes about 15 seconds from the pressure holding process until the mold opening is started, it is not necessary to wait until the molded product is forcibly cooled to room temperature after the mold opening, and the molded product 22 can be released immediately. . Since the molding cycle time is about 1 minute, shortening by 10 seconds can greatly contribute to the improvement of production efficiency.
Note that the temperature of the low-temperature medium during forced cooling and the duration time of forced cooling differ depending on the shape and material of the molded product, so if the shape and material are different, it is necessary to change appropriately according to the above-described conditions.

  Switching of the flow path medium for forcibly cooling the core block 3 is performed by controlling the opening / closing timing of a valve in the medium switching means 12 of the temperature adjusting means 9 by the medium switching control means 21. That is, by opening the third and fourth valves 15 and 16 and closing the first and second valves 13 and 14, the medium supplied to the first medium flow path can be instantaneously switched. As described above, the core block 3 is made of a material having a high thermal conductivity and a small heat capacity, and is provided with a heat insulating layer 7 on the side surface thereof, so that the movable die 2 and the ejector block 4 are provided during forced cooling. Heat transfer from can be suppressed. As a result, the time required to adjust the core block 3 to a desired temperature can be shortened, and the production efficiency can be improved.

  In the above description, the forced cooling for the first mold part is started immediately after the completion of the filling process. However, the time until the medium temperature is conducted to the molded product through the first mold portion differs depending on the shape, size, material, and the like of the mold. The time required for the cooling process varies depending on the material and size of the molded product. Therefore, the start timing of forced cooling may be immediately after completion of the pressure holding process. Alternatively, a predetermined time may elapse immediately after completion of the filling process. Normally, the cooling time in the cooling process of FIG. 3 is longer than the forced cooling time, so if forced cooling is performed during that time, the mold opening process and the mold releasing process can be proceeded immediately after the cooling process is completed. it can.

  As described above, according to the invention of the present embodiment, after the molding material is filled in the molding material cavity, the molded product is put through the first mold part for a predetermined time from before the mold parts are opened. Since the temperature adjustment means for forced cooling is provided and the molded product is forcibly cooled through the first mold part, the amount of deformation due to thermal shrinkage and internal stress of the molded product can be reduced even after the molded product is released. The molding cycle can be shortened while minimizing.

  In addition, since the molding surface of the first mold part is processed with higher accuracy than the molding surface of the second mold part, by forced cooling of the molding surface that requires high accuracy, A molded product having a highly accurate molded product surface can be formed by minimizing the amount of deformation due to stress.

  Also, by providing a heat insulating layer between the first mold part and the second mold part, the temperature of the first mold part can be adjusted in a short time without being affected by the heat of the second mold part. And the molding efficiency can be improved.

  Further, the first mold part is made of a material having a smaller heat capacity than that of the second mold part, so that the first mold part can be used when the molded product is forcibly cooled or when the first mold part is heated. The mold part can be adjusted to a desired temperature in a short time, and the molding efficiency can be improved.

  Also, a first medium flow path is provided in the first mold part, a second medium flow path is provided in the second mold part, and a high temperature medium supply part, a low temperature medium supply part, and a medium switching means are provided in the temperature adjusting means. The high temperature medium is supplied from the high temperature medium supply unit to the first medium flow path and the second medium flow path to heat both mold parts, and the low temperature medium is transferred to the first medium flow path by the medium switching means only during forced cooling. Since the first mold portion is forcibly cooled by supplying the molding material, when the molding material is filled in the molded product cavity, the temperature of the molding material can be suppressed and fluidity can be ensured while the molding material is secured. In addition to the effect of shortening the molding cycle while minimizing the amount of deformation due to thermal shrinkage and internal stress of the molded product after releasing the molded product, the crystallization is promoted. Minimizing deformation of molded parts due to crystal strain It can be.

  The forced cooling is started immediately after completion of the filling process for filling the molding cavity with the molding material, immediately after completion of the pressure holding process, or immediately after completion of the filling process. Therefore, the optimum molding cycle can be controlled depending on the shape and size of the molded product.

  In addition, when the molding material is a resin material, forced cooling is performed until the temperature of the molded product falls below the glass transition point, so the molded product is completely solidified and molded by external force when releasing the molded product. The deformation of the product can be minimized, and at the same time, the deformation of the molded product due to solidification shrinkage, crystal distortion, and heat shrinkage can be minimized.

Embodiment 2. FIG.
FIG. 5 is a conceptual diagram showing a molding die apparatus according to the second embodiment. The difference from the first embodiment is that there are a plurality of molding cavities (two in this embodiment) and the shape of the molded product is slightly different. Other basic structures and molding methods are implemented. This is the same as Form 1. Therefore, it demonstrates centering on a different part.

  FIG. 7 shows an example of a molded product according to the present embodiment. (A) of a figure is a front view, (b) is a side view. The molded product 44 is made of PPS resin, and has an arc-shaped molded product curved surface 44a, a first molded product flat surface 44b, a second molded product flat surface 44c, a first claw portion end surface 44d, a second claw portion end surface 44e, It is assumed that the first molded product side surface 44f and the second molded product side surface 44g are configured, and of these, the arc-shaped molded product curved surface 44a is required to have particularly high curvature accuracy. However, this shape is only an example, and the shape of the molded product is not particularly limited as long as it is configured from a plurality of surfaces. Also, the molding material is not particularly limited to the PPS resin.

  Next, the structure of the molding die will be described in detail with reference to FIG. The molding die shown in the figure is an example of a two-piece molding die that can simultaneously mold two molded products, and a first molded product cavity 39A and a second molded product cavity 39B are arranged. The flow path for guiding the molding material to each molded product cavity includes a mold inlet 40, a first material flow path 41, a second material flow path 42, and molded product cavity inlets 43A and 43B. The first mold portion for molding a molded product surface that requires high accuracy corresponds to the core block 33 for molding the molded product curved surface 44a. Further, the second mold part is a part for molding all other molded product surfaces, the fixed-side die 31 for molding the second molded product plane 44c, the first molded product plane 44b, and the second claw end surface. 44e, the movable mold 32 for molding the first and second molded product side surfaces 44f, 44g, the ejector block 34 for molding the first claw end surface 44d, and a part of the flow path are molded and separated. It is composed of an ejector block 35 serving as an ejector for molding. Among these, the ejector blocks 34 and 35 are incorporated in the movable mold 32. The core block 33 has a higher thermal conductivity than other molding mold components, uses a copper alloy or an aluminum alloy having a small heat capacity, and is processed with high accuracy, with a heat insulating layer 36 interposed therebetween. And fixed to the movable mold 32. In addition, since the material and structure of the heat insulation layer 36 are the same as what was demonstrated in Embodiment 1, description is abbreviate | omitted. Forming mold components other than the core block 33 are formed of steel materials such as alloy tool steel for cold mold (SKD-11) and stainless steel (SUS-420, SUS-440), but are not limited thereto. is not.

In each of the fixed side mold 31, the movable side mold 32, and the core block 33, there are provided flow paths 31A, 32A, 33A through which a medium for mold temperature adjustment flows. Among these, the medium flow paths 31A and 32A (hereinafter collectively referred to as the second medium flow path) provided in the fixed-side mold 31 and the movable-side mold 32 are connected in series with each other via the communication flow path 37. Connected to the hot medium supply unit 10 of the temperature adjusting means 9. On the other hand, the medium flow path 33A provided in the core block 33 (hereinafter referred to as the first medium flow path) is independent of the second medium flow paths 31A and 32A, and the medium is switched via the communication flow path 38. The high temperature medium supply unit 10 and the low temperature medium supply unit 11 are connected via the means 12. The medium for adjusting the mold temperature uses water that is excellent in heat exchange efficiency and easy to handle, but is not limited thereto.
Since the temperature adjusting means 9 is the same as that shown in FIG. 1 described in the first embodiment, description of the reference numerals and description of the operation are omitted. Since the set temperature of the medium is the same as that of the first embodiment, the description thereof is omitted.

  Next, the operation will be described. FIG. 6 is an explanatory view showing a molding process of a molded product by the molding die apparatus of the second embodiment. In the molding process of the molded product, the switching state between the high temperature medium and the low temperature medium flowing through the first medium flow path 33A is the same as that in FIG. 3 described in the first embodiment, and will be described below with reference to FIG. 3 as appropriate. Molding is performed continuously by repeating the order of mold closing process → filling process → holding process → cooling process → mold opening process → mold releasing process → mold closing process.

  First, as shown in FIG. 6A, the movable mold 32 is abutted against the fixed mold 31 to close the molding dies. At the same time, the core block 33 and the ejector blocks 34 and 35 are arranged inside the molding die (mold closing process). From this state, as shown in FIG. 6B, the molten molding material 45 is injected from the molding die inlet 40. The molding material 45 first flows through the first material channel 41, and then is divided into both sides by the second material channel 42, passes through the first and second molded product cavity inlets 43A and 43B, respectively, and passes through the first and first molding channels. 2 Filled into the molded product cavities 39A, 39B (filling process). Since the filled molding material 45 undergoes volume shrinkage with phase transformation, a predetermined pressure is continuously applied to the molding material 45 in the state of FIG. 6C in order to compensate for the shrinkage (pressure holding process). When the filling process is completed and the pressure holding process is started, the first medium flow path 33A is switched from the hot medium supplied up to then to the cold medium, and forced cooling of the core block 33 is started. Then, from this state, the phase-change is advanced and solidified until the filled molding material 45 can maintain the shapes of the molded product cavities 39A and 39B (cooling process). Thereafter, as shown in FIG. 6 (d), the movable die 32 is separated from the fixed die 31, and the first claw end surface 44d of the molded product 44 and the central portion of the material flow path are ejected by the ejector blocks 34 and 35. The molded product 44 is released by protruding (mold opening process, mold release process). Simultaneously with the mold release, in order to raise the temperature of the core block 33 again, the low temperature medium is switched to the high temperature medium for the first medium flow path 33A. And it returns to the state (mold closing process) shown to Fig.6 (a) again, and it shape | molds continuously by repeating the above-mentioned process sequentially.

  As shown in FIG. 3, the second medium flow paths 31A and 32A are continuously supplied with a high-temperature medium from the high-temperature medium supply unit 10 during a series of molding processes, and the fixed-side mold 31 and the movable-side mold 31 The mold 32 is heated. The first medium flow path 33A is supplied with a high-temperature medium from the high-temperature medium supply unit 10 from the mold closing process to the filling process, and immediately after the completion of the filling process. , The low temperature medium is supplied from the low temperature medium supply unit 11 to the first medium flow path 33A, and the core block 33 is forcibly cooled. The molding material applied in the present embodiment is a PPS resin. For the same reason as described in the first embodiment, the temperature of the high-temperature medium is 423K, and the temperature of the low-temperature medium is 293K. Note that when a material other than PPS is applied as the molding material, the optimum temperature condition is also different and needs to be appropriately changed.

In the above description, forced cooling is performed immediately after completion of the filling process, but the start timing of forced cooling is the same as in the first embodiment immediately after completion of the pressure holding process or after a predetermined time has elapsed since completion of the filling process. It may be later.
In the case of a simple shape such as the molded product 44, the molded product shrinks and is deformed by cooling, but there are few sites where the deformation is restrained by the molding die, and the generation of thermal stress is small. Therefore, even if forced cooling is performed before the mold opening process of the molded product, the deformation of the molded product due to thermal stress is small. After filling the molding cavity with molding material, forced cooling before mold opening can reduce the forced cooling time after the mold opening process and form highly accurate molded articles extremely efficiently. Is possible.

The time for which the forced cooling is continued is determined by the time required for the molded product 44 to cool to a desired temperature. In the present embodiment to which the PPS resin is applied, as an example, when the side length of the molded product is about several centimeters, it is about 15 seconds or longer. Since it takes about 15 seconds from the pressure holding process to the start of the mold opening process, it is not necessary to wait until the molded product is forcibly cooled to room temperature after the mold opening process, and the molded product 44 is released immediately. can do.
The temperature of the low-temperature medium at the time of forced cooling and the duration of forced cooling need to be appropriately changed according to the above-described conditions depending on the shape, size, material, etc. of the molded product.

  In the above description, the case where there are two molding cavities has been described, but three or more may be used. Then, production efficiency can be further increased.

  As described above, according to the present embodiment, after a plurality of molded product cavities are filled with a molding material, molding is performed for a predetermined time through the first mold part before the mold parts are opened. Since the temperature adjustment means for forcibly cooling the product is provided and the molded product is forcibly cooled through the first mold part, even after the molded product is released, the molded product is deformed by thermal contraction or internal stress. The molding cycle can be shortened while minimizing the amount, and more than one can be molded simultaneously, so that the molding cycle of the molded product can be further shortened.

Similarly to the first embodiment, a first medium flow path is provided in the first mold portion, a second medium flow path is provided in the second mold portion, a high temperature medium is supplied to both medium flow paths, and forced Since the low temperature medium is supplied to the first medium flow path by the temperature adjusting means only at the time of cooling, when the molding material is filled into the molded product cavity, the temperature drop of the molding material can be suppressed and the fluidity can be secured. At the same time, since rapid cooling of the molding material can be suppressed, crystallization can be promoted and deformation of the molded product due to crystal distortion can be minimized.
Furthermore, the effect of processing the molding surface of the first mold part with higher accuracy than the molding surface of the second mold part, and the provision of a heat insulating layer between the first mold part and the second mold part The effects described in the first embodiment, such as the effects, can be obtained in this embodiment as well.
In this way, deformation of the molded product due to solidification shrinkage, thermal shrinkage, thermal stress, crystal distortion, and external force can be minimized, and a highly accurate molded product can be molded extremely efficiently.

  In Embodiments 1 and 2, the case where the molding material is a PPS resin (polyphenylene sulfide resin), which is a crystalline resin, has been described. However, similar effects can be expected even when other molding materials are used. For example, the following molding materials can be applied. (1) polyolefin resin, (2) aliphatic polyamide resin, (3) aromatic polyamide resin, (4) polyester resin, (5) crystalline resin, (6) amorphous resin, (7) Liquid crystal polymer, and the like. Moreover, resin which mix | blended fillers, such as these alloys and glass fiber, may be sufficient.

  In addition to the resin, it can also be applied to a die-casting mold made of a metal material represented by, for example, an aluminum alloy or a magnesium alloy.

  It can also be applied to powder molding using an inorganic material. Examples of this type of powder molding include ceramic injection molding, metal powder injection molding, and cemented carbide injection molding. In these powder moldings, a binder is mixed to impart plasticity to the molding material.

  In addition to resin molding dies, the present invention can be applied to a wide range of molding dies such as metal material die casting dies and inorganic material powder molding dies.

It is a conceptual diagram which shows the shaping die apparatus by Embodiment 1 of this invention. It is explanatory drawing explaining the shaping | molding process by Embodiment 1 of this invention. It is a figure which shows the switching aspect of the medium supplied to each medium flow path in the formation process by Embodiment 1 of this invention. It is a figure which shows the molded article by Embodiment 1 of this invention. It is a conceptual diagram which shows the molding die apparatus by Embodiment 2 of this invention. It is explanatory drawing explaining the shaping | molding method by Embodiment 2 of this invention. It is a figure which shows the molded article by Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed side type | mold 2 Movable side type | mold 1A, 2A, 5A, 6A 2nd medium flow path 3A 1st medium flow path 3 Core block (1st metal mold | die part) 4 Ejector block 5, 6 Slide block 7 Heat insulation layer 9 Temperature adjusting means 10 High temperature medium supply section 11 Low temperature medium supply section 12 Medium switching means 22 Molded product 29 Molded product cavity 30 Molding material 31 Fixed side mold 32 Movable side mold 31A, 32A Second medium flow path 33 Core block (first block) 1 mold part) 33A 1st medium flow path 34, 35 Ejector block 36 Heat insulation layer 39A, 39B Molded product cavity 44 Molded product 45 Molding material.

Claims (10)

  A first mold part for molding one molded product surface, and a second mold part for molding the other molded product surface, the first mold part and the second mold part, In a molding die apparatus for molding a molded product by filling the molded product cavity defined between the molding cavities with the molding material filled in the molded product cavity and then opening both mold parts A molding die apparatus, further comprising a temperature adjusting means for forcibly cooling the molded product through the first mold part for a predetermined time from before.   2. The molding die apparatus according to claim 1, wherein the molding surface of the first mold part is processed with higher accuracy than the molding surface of the second mold part.   3. The molding die apparatus according to claim 1, wherein a heat insulating layer is provided between the first mold part and the second mold part.   4. The molding die apparatus according to claim 1, wherein the first mold part is made of a material having a smaller heat capacity than the second mold part. Mold equipment.   5. The molding die apparatus according to claim 1, wherein a plurality of the molded product cavities are provided.   6. The molding die apparatus according to claim 1, wherein a first medium flow path is provided in the first mold portion, and a second medium flow path is provided in the second mold portion. The temperature adjusting means includes a high temperature medium supply unit, a low temperature medium supply unit, and a medium switching unit, and supplies the high temperature medium from the high temperature medium supply unit to the first medium flow path and the second medium flow path. The first mold part and the second mold part are heated, and at the time of the forced cooling, the medium switching means is switched to supply the low temperature medium from the low temperature medium supply unit to the first medium flow path. The first mold part is forcibly cooled by the molding tool apparatus.   A molding material is filled in a molding cavity defined between a first mold part for molding one molded product surface and a second mold part for molding the other molded product surface. In a molding method for molding a molded product, after the molding material is filled in the molded product cavity, the molded product is passed through the first mold part for a predetermined time before the mold parts are opened. A molding method characterized by forced cooling.   8. The molding method according to claim 7, wherein a high-temperature medium is circulated through a first medium flow path provided in the first mold part and a second medium flow path provided in the second mold part. A molding method characterized in that the part is heated and the first mold part is forcibly cooled by circulating a low-temperature medium through the first medium channel during the forced cooling.   9. The molding method according to claim 7, wherein the forced cooling is started immediately after completion of a filling process of filling the molding cavity with the molding material, or completion of a pressure holding process following the filling process. Immediately after the completion of the filling process, or after a lapse of a predetermined time.   The molding method according to any one of claims 7 to 9, wherein when the molding material is a resin material, the forced cooling is performed until the temperature of the molded product is equal to or lower than the glass transition point. A characteristic molding method.

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