JP2008012784A - Method for controlling injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling an injection molding machine which can produce a multi-material molding without quality variation in each molding cycle. <P>SOLUTION: In the method for controlling the injection molding machine 1, a mold device 10 having a plurality of cores 8 which can be changed in turn to be put into each of a plurality of cavities 14 and 15 corresponding to different molding materials and constitute the opposed surfaces of the cavities 14 and 15 is installed between a fixed platen 5 and a movable platen 6, the movable platen 6 is made to approach the fixed platen 5, and the volumes of the cavities 14 and 15 are reduced, so that the molding materials injected into the cavities 14 and 15 are compression-molded. The mold matching between one of the cavities 14 and 15 and each core 8 is carried out. The distance between the fixed platen 5 and the movable platen 6 when the mold device 10 is clamped is measured by a detectors 11 and 12, and setting is carried out for each core 8 with the distance used as an origin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control method for performing multi-material molding by injection compression molding.

  A technique for performing a compression process in injection compression molding by parallel control is disclosed in Patent Document 1, for example. Patent Document 1 discloses a fixed die plate that holds a fixed mold, a movable die plate that holds a movable mold, a tie bar that is supported by the fixed die plate and penetrates the movable die plate, and the movable die plate that A plurality of mold clamping means that perform clamping by moving relative to the fixed die plate, and a plurality of measurements that measure the distance of the movable die plate from the fixed die plate that is attached to or near the mold clamping means. A mold clamping device comprising a device and a control device for controlling the movable die plate to move in parallel based on a value measured by the measurement device and a movement instruction value, wherein the plurality of measurement devices are arranged on their scales. It has an absolute origin (O), the absolute origin (O) is within the movable range of the movable die plate, and the precise reference mold is fixed. The value stored in the control device is the absolute origin (O) position of each scale when the fixed die plate and the movable die plate are made parallel to each other. The present invention relates to a mold clamping device that is set to be an origin of an absolute value position of a movable die plate.

  In patent document 1, since the single molding material is used, the cavity is also one. However, in order to mold a multi-material molded product using a multi-material molding material, it is necessary to have a configuration in which a plurality of cavities are provided and the same number of cores as the cavities are sequentially interchanged. However, when there is a decrease in the machining accuracy of the core, the thickness deviation in the mold clamping direction is irregularly distributed on the parting surface. Therefore, the deviation of the thickness of the mold device when the mold device is pressed through the core is the deviation of the distance at the same place on the surface of the platen between the movable platen and the fixed platen before and after replacing the core. Will appear. This is a detection error of the opening amount of the cavity between the cavities of different cores when detecting the opening amount of the mold based on the clamping time of the mold apparatus and controlling the compression molding. A change is caused in the compression form of the molding material for every cavity. For this reason, quality variations occur in each molding cycle in a multi-material molded product.

Japanese Patent No. 3340179

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an injection molding machine control method capable of producing a multi-material molded product without quality fluctuation for each molding cycle.

  According to the present invention, a mold apparatus including a plurality of cores that can be sequentially replaced with a plurality of cavities corresponding to different molding materials and that constitute opposed surfaces of the plurality of cavities is provided between a fixed platen and a movable platen. An injection molding machine control method for compression-molding a molding material injected into the cavity by attaching the movable plate close to the fixed plate and reducing the volume of the cavity, comprising: Injection is performed by matching the mold with each core, measuring the distance between the fixed platen and the movable platen when the mold apparatus is clamped with a detector, and setting the distance as the origin for each core. The present invention relates to a method for controlling a molding machine.

  According to the control method of the injection molding machine of the present invention, a multi-material molded product can be produced without quality fluctuation for each molding cycle.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing an outline of an injection molding machine for carrying out the present invention. FIG. 2 is a plan view showing an outline of another injection molding machine for carrying out the present invention.

  As shown in FIG. 1, the injection molding machine 1 includes a first injection device 2, a second injection device 3, and a mold clamping device 4. The mold clamping device 4 includes a fixed platen 5 to which the fixed die 7 is attached, a movable platen 6 that is driven close to and away from the fixed platen 5 and capable of being clamped, and a movable die 9 is attached. The fixed die 7 and the movable die 9 The distance between the fixed plate 5 and the movable plate 6 is arranged between the fixed plate 7 and the movable plate 9 and the core 8 constituting the mold apparatus 10 together with the fixed die 7 and the movable die 9. It comprises a plurality of position detectors 11 and 12 that measure near the four corners of the mold apparatus 10 and a control device 16 that controls the injection molding machine 1 by inputting signals from the position detectors 11 and 12. In the core 8, a convex portion that fits into the concave portion of the fixed mold 7 and a convex portion that fits into the concave portion of the movable die 9 are integrally formed back to back, and a rotating shaft 13 is formed at the center between both convex portions of the same shape. Is provided and can be rotated 180 degrees. When the movable platen 6 comes close to the fixed platen 5 and is mold-matched, both convex portions of the core 8 are fitted into the concave portion of the fixed die 7 and the concave portion of the movable die 9 to form a cavity 14 and a cavity 15, respectively. .

  The injection molding machine 1 injects the first molding material plasticized by the first injection device 2 and the second molding material plasticized by the second injection device 3 into the cavities 14 and 15 to produce a multi-material molded product. It is to be molded. The first molding material and the second molding material are different in color and material from each other.

  The molding method will be specifically described. The mold device 10 is clamped by the movable plate 6 and the fixed plate 5, and the first molding material is injected from the first injection device 2 into the cavity 14 through the fixed die 7. The movable platen 6 is separated from the fixed platen 5 and the mold is opened, and the core 8 is rotated 180 degrees, whereby the first molded material half-molded product formed in the cavity 14 is attached to the core 8 and the cavity 8 Move to the 15th side. In this state, the mold apparatus 10 is pressed again. Then, the second molding material is injected from the second injection device 3 into the cavity 15 via the movable die 9. Thereby, the second molding material is injected into a space other than the area occupied by the semi-molded product in the cavity 15 to complete the molded product. Next, the mold is opened and the molded product is taken out from the cavity 15. Thereafter, continuous molding is performed by repeating the series of operations.

  When a semi-molded product is molded in the cavity 14, injection molding is effective in that a molded product having a large thin area can be obtained with a good low distortion product. Injection compression molding is performed by injecting a first molding material in a state where a predetermined distance is opened between the fixed mold 7 and the core 8 of the mold apparatus 10 in advance to increase the cavity volume, and the mold is injected during or after completion of the injection. The device 10 is pressed and the first molding material in the cavity 14 is compressed and spread to fill the cavity 14. At this time, if the cavity facing surface of the core 8 that is the pressing surface of the first molding material in the cavity 14 does not move parallel to the cavity surface of the fixed mold 7, the thickness of the molded product will not be uniform. Therefore, the inclination of the movable mold 9 is detected by the position detectors 11, 12 provided in the vicinity of the four corners of the mold apparatus 10, and the movable platen 6 is pressed and driven so that the inclination is parallel to the fixed mold 7. A plurality of pressing devices (not shown) are controlled. Note that injection compression molding may be performed without performing this parallel movement control. In that case, a plurality of position detectors can be used without requiring a plurality of position detectors.

  By the way, the measurement origin of each of the position detectors 11 and 12 is when the mold apparatus 10 is clamped and the fixed mold 7 and the core 8 and the core 8 and the movable mold 9 are in close contact. However, the contact surfaces of the core 8 with the fixed mold 7 and the movable mold 9 are often not parallel because of a decrease in processing accuracy. Therefore, the thickness of the mold apparatus 10 that is pressed before and after the core 8 is rotated by 180 degrees, that is, the distance between the fixed platen 5 and the movable platen 6 is changed after the core 8 is rotated 180 degrees. It changes corresponding to the difference in thickness at the same position. Therefore, when the origin is set when the mold device 10 is pressed either before or after the core 8 is rotated 180 degrees, the numerical value is different from the one origin at the time of the other pressing. Since the origin is shifted, the predetermined mold opening amount of compression molding on the other side changes, and uniform and correct compression molding becomes impossible for each core.

  Therefore, the measurement origins of the position detectors 11 and 12 are obtained by pressing the mold apparatus 10 at both time points before and after the core 8 rotates 180 degrees. Specifically, before starting the molding operation, first, the core 8 of the mold apparatus 10 is pressed against both cavities in one fitted state, and the position signals of the position detectors 11 and 12 are inputted. In the control device 16, the value of one storage unit of the position signal is reset to zero or replaced with a predetermined value as one origin. Next, the core 8 is rotated 180 degrees so that the core 8 of the mold apparatus 10 is pressed against both cavities in the other fitted state, and the control device 16 to which the position signals of the position detectors 11 and 12 are inputted. The value of the other storage part of the position signal is reset to zero or replaced with a predetermined value as the other origin. When the core 8 of the mold apparatus 10 is molded into one of the two cavities, the mold opening amount is controlled as a distance from one of the origins detected by the position detector. When the mold 8 is molded in the other fitting state with respect to both cavities, the mold opening amount control is performed on the other side detected by the position detector. This is executed based on a numerical value stored in the other storage unit as a distance from the origin.

  An example in which the present invention is applied to another injection molding machine will be described with reference to FIG. The injection molding machine 21 includes a first injection device 22, a second injection device 23, and a mold clamping device 24. The mold clamping device 24 includes a fixed plate 25 to which the fixed die 27 is attached, a movable plate 26 that is driven to be capable of being pressed and clamped close to and away from the fixed plate 25, and a fixed die 27 and a movable die 29. A distance between the fixed plate 25 and the movable plate 26 between the fixed plate 27 and the core 28 constituting the mold device 30 together with the fixed die 27 and the movable die 29. Are measured in the vicinity of the four corners of the mold device 30, and a control device 16 for controlling the injection molding machine 21 by inputting signals from the position detectors 31, 32 and the like. In the core 28, a convex portion that fits into one concave portion of the fixed mold 27 and a convex portion that fits into the other concave portion of the fixed mold 27 are integrally formed on the same board surface, and the center between both convex portions having the same shape is formed. Is provided with a rotation drive device 33, which can rotate 180 degrees in a plane perpendicular to the clamping shaft. When the movable platen 26 comes close to the fixed platen 25, both convex portions of the core 28 are fitted into both concave portions of the fixed mold 27, so that a cavity 34 and a cavity 35 are formed.

  The injection molding machine 21 injects the first molding material plasticized by the first injection device 22 and the second molding material plasticized by the second injection device 23 into the cavities 34 and 35 to produce a multi-material molded product. It is to be molded. The first molding material and the second molding material are different in color and material from each other.

  The molding method will be specifically described. The mold device 30 is pressed by the movable plate 26 and the fixed plate 25, and the first molding material is injected from the first injection device 22 into the cavity 34. Further, the second molding is performed in a space other than the area occupied by the semi-molded product of the first molding material formed in the cavity 34 in the pre-molding cycle and moved to the cavity 35 by rotating the core 28 by 180 degrees. Material is injected from the second injection device 23. The movable platen 26 is separated from the fixed platen 25 and opened, and the molded product is taken out from the cavity 35. Thereafter, continuous molding is performed by repeating the series of operations. The injection compression molding to the cavity 34 and / or the cavity 35 is performed in the same manner as the embodiment based on FIG. 1 described above, and therefore the present invention is also implemented in the same manner.

  The present invention is not limited to the embodiments described above, and various modifications can be added and implemented without departing from the spirit of the invention. For example, in the above embodiment, two cavities have been described, but three or more cavities may be used. In this case, it is natural that the same number of cores, injection devices, molding materials, and position signal storage units as the cavities are provided. Further, although the core is illustrated as being replaced with each cavity by rotation, the core may be configured to move linearly. In that case, the number of cores may be provided more than the number of cavities.

It is a top view which shows the outline | summary of the injection molding machine which implements this invention. It is a top view which shows the outline | summary of the other injection molding machine which implements this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 Injection molding machine 2,22 1st injection apparatus 3,23 2nd injection apparatus 4,24 Clamping apparatus 5,25 Fixed board 6,26 Movable board 7,27 Fixed mold 8,28 Core 9,29 Movable Mold 10, 30 Mold device 11, 12, 31, 32 Position detector 13 Rotating shaft 14, 15, 34, 35 Cavity 16 Control device 33 Rotation drive device

Claims (2)

A plurality of cavities corresponding to different molding materials can be sequentially replaced with each other, and a mold apparatus having a plurality of cores constituting the opposed surfaces of the plurality of cavities is attached between the fixed platen and the movable platen, A control method of an injection molding machine for compressing and molding a molding material injected into the cavity by bringing the movable plate close to the fixed plate and reducing the volume of the cavity,
The cavity is matched with each core, and the distance between the fixed platen and the movable platen when the mold apparatus is clamped is measured by a detector, and the distance is set as the origin to the center. A method for controlling an injection molding machine, characterized in that it is set for each child.   2. The method of controlling an injection molding machine according to claim 1, wherein the number of the cavities and the cores is two, and the two cores are rotated in unison with each other and replaced with the cavities.

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