JP2006102783A - Die casting machine and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely avoid generation of plastic deformation in a mold assembly by highly accurately measuring the strain generated in a mold assembly (a fixed main die) even when a foreign matter is caught at the time of mold clamping. <P>SOLUTION: A die casting machine is provided with a mold assembly A consisting of a movable die and a fixed main die, a mold clamping device performing mold clamping by moving the movable die toward the fixed main die, and an injection device performing press-fitting of a molten metal or a melted resin into a cavity space of the mold assembly mold-clamped. In the die casting machine, a strain gauge 47 is mounted on a fixed main die 15. The signals of the gauge are sent to a control device 49, and, when the amount of strain exceeds a set value (A) that is not more than the elastic limit, the control device 49 outputs a signal to stop the operation of the mold clamping device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a die casting machine for casting a product by pressing a molten metal or the like into a mold and an operation method thereof.

  The die casting machine includes a mold device composed of a movable mold and a fixed main mold, a mold clamping apparatus that moves the movable mold toward the fixed main mold and performs mold clamping, and a cavity space of the mold apparatus that has been clamped. It is equipped with an injection device that press-fits molten metal or molten resin, etc., and the molten metal or resin is filled in the cavity space of the mold device at high pressure, and then the molded product is molded by cooling and solidifying in the cavity I have to.

  FIG. 2 is a schematic view showing an example of a conventional die casting machine. A tie bar 13 is installed between a fixed platen 11 fixed to a substrate 10 and a link housing 12, and the tie bar 13 is attached to the tie bar 13. A movable board 14 is attached so as to freely advance and retreat along. The fixed platen 11 and the movable platen 14 are attached with a mold device composed of a fixed main mold 15 and a movable mold 16 so as to face each other. In addition, a toggle mechanism 21 is disposed between the link housing 12 and the moving board 14, and the cross 23, which constitutes the toggle mechanism 21, is moved forward and backward by an actuator such as a hydraulic cylinder (not shown), whereby the link 23, 24 and 25 actuate to move the moving board 14 forward and backward along the tie bar 13. Thereby, the movable mold 16 is brought into contact with and separated from the fixed main mold 15, and mold clamping and mold opening are performed.

  FIG. 2 shows a state in which the mold is closed. In this state, molten metal (molten metal or resin) is press-fitted through the runner 31 into the cavity space clamped from the injection device 30. After a predetermined time has elapsed, cooling is performed, the tie bar 13 is operated, the moving plate 14 is moved, the mold is opened, and the product is taken out. In the process of mold clamping and molten metal press-fitting, stress is generated in the mold apparatus. FIG. 4 shows an example of the relationship between the stress generated in the fixed main mold 15 and time. In the normal case, as shown by the curve A (steady value), the heat is generated from the start of mold clamping to the completion of mold clamping. Stress increases to a certain value with strain. When the molten metal is injected at the time when the temperature reaches a predetermined temperature, the stress is increased to a predetermined value along with the press-fitting. After being left in that state for a certain period of time, it is cooled and the mold is opened. The fixed main mold 15 is designed so as not to exceed the elastic limit in the stress range of the curve A (steady value), and no trouble occurs even if repeated injection molding is performed.

  In some cases, foreign matter may be caught between the fixed main mold 15 and the movable mold 16. In this case, an example of the stress generated in the fixed main mold 15 is shown as a curve B (when biting) in FIG. In this case, when the mold clamping is completed, a stress exceeding the elastic limit occurs in the fixed main mold. In that case, since the stress is further increased by the injection of the molten metal, plastic deformation that cannot be recovered occurs in the mold, causing a so-called setback failure.

  FIG. 3 shows an example of the fixed main mold 15 and the movable mold 16. In this example, the fixed main mold 15 includes a fixed insert 41, the movable mold 16 includes a movable insert 42 and a slide core holder 43, A slide core 44 is inserted into the slide core holder 43 to form a cavity 45. Such a precise mold apparatus is often used when casting a precision automobile part or the like using a die casting machine. However, the mold apparatus is in a state where foreign matter bites as described above. When the mold is clamped, as shown by a curve B in FIG. In that case, since the slide core 44 is retracted from the normal position by the amount of deformation, the cavity space is expanded correspondingly, and the product thickness is increased. If the product thickness exceeds the specified thickness, the product will be defective and must be avoided. Further, if the slide core 44 is not in the proper position, a gap is generated at the contact surface between the cores, which may cause burrs when the molten metal is injected. For this reason, in order to obtain a precise injection molded product, it is a big problem not to cause plastic deformation in the mold apparatus, particularly the fixed main mold.

Patent Document 1 and Patent Document 2 describe a die casting machine (injection molding machine) that can stop mold clamping when a foreign object is caught between molds. As shown in FIG. 2, the apparatus described in Patent Document 1 includes a moving platen 14 composed of a toggle side member 14b and a mold side member 14a, and a distortion member 17 is disposed between them to monitor the amount of distortion. The injection molding machine is stopped when it is determined that a foreign object is sandwiched between the fixed main mold 15 and the movable mold 16. In the apparatus described in Patent Document 2, a displacement sensor that measures the amount of tie bar displacement associated with mold clamping is attached, the mold clamping force is measured from the amount of tie bar displacement, and the mold clamping can be stopped in the event of an abnormality.
JP 2004-90654 A JP 7-68610 A

  As described in Patent Document 1 and Patent Document 2, a strain member and a displacement sensor are attached to a die casting machine, and from the information from there, abnormalities in stress generated in a mold (mold device) are detected, and the mold is clamped. It is possible to stop. However, both devices detect the distortion and displacement of other members caused by the distortion (stress) generated in the mold apparatus, that is, the distortion of the moving plate and the displacement of the tie bar, and stop the mold clamping. Basic information for this purpose, the stress of the mold apparatus or the amount of distortion caused by it is not used as a direct information source. For this reason, in the case of a precise mold that must avoid even a slight plastic deformation in the mold apparatus, the information obtained is less accurate and the plastic deformation occurs in the mold apparatus. It is also possible to overlook. Further, it is information obtained via several members, and it is necessary to accurately correlate the distortion amount of the mold apparatus and the distortion amount (displacement amount) of the measurement site, but this is not easy.

  The present invention has been made in view of the circumstances as described above, and is capable of measuring distortion generated in a die apparatus (particularly, a fixed main mold) of a die casting machine with high accuracy, so that the mold apparatus is subjected to plastic deformation. It is an object of the present invention to provide a die casting machine that can completely avoid the occurrence. Moreover, it aims at providing the driving | running method.

  A die casting machine according to the present invention includes a mold apparatus composed of a movable mold and a fixed main mold, a mold clamping apparatus that moves the movable mold toward the fixed main mold and performs mold clamping, and a mold apparatus that is clamped. A die casting machine having an injection device for press-fitting molten metal or molten resin into a cavity space, wherein a strain gauge mounted on a fixed main mold and a value relating to a strain amount obtained from the strain gauge are preset values. And a control means for stopping the operation of the mold clamping device when exceeding.

  The present invention is also an operation method of the above-described die casting machine, wherein a stress value lower than a stress value at which plastic deformation occurs in the fixed main mold is set as a reference value, and the value related to the strain amount obtained from the strain gauge is Also disclosed is a method of operating a die casting machine characterized in that the clamping is stopped when a stress value that is a reference value is exceeded.

  In the above die casting machine, a strain gauge is mounted on the fixed main mold, and the amount of strain of the fixed main mold can be directly detected. By continuously monitoring the amount of strain (stress) of the fixed main mold during casting, it is possible to directly know whether the fixed main mold is in the elastic range or in the plastic deformation range beyond the elastic limit during mold clamping. it can. A value that is a predetermined amount lower than the stress value, which is the elastic limit, is set as a set value, and when the value related to the strain amount (stress value) obtained from the strain gauge exceeds a preset value by the control means, the mold clamping is performed. By stopping the operation of the apparatus, it is possible to reliably prevent plastic deformation from occurring in the mold apparatus, particularly the fixed main mold. Therefore, even if the mold apparatus has an elaborate structure, it is possible to continuously obtain a good cast product without producing defective products or burrs.

  In the present invention, the position where the strain gauge is mounted on the fixed main mold is not limited, but it is desirable to mount the strain gauge at a position where distortion is most likely to occur due to the movable mold. Therefore, when the movable type is provided with the slide core holder, the strain cage is preferably mounted on the contact surface of the fixed core type slide core holder or in the vicinity of the corner portion thereof. As the strain gauge, any conventionally known strain gauge can be used on the condition that it is not damaged by heat during casting. Since the strain gauge may be thermally damaged by repeated casting, it is also effective to attach the strain gauge to the fixed main mold so as to be replaceable.

  According to the present invention, it is possible to accurately measure the distortion generated in a die casting machine die device (particularly, a fixed main die), and thus, even when a foreign object is caught during clamping, the die device is plastic. It is possible to obtain a die casting machine and its operation method that can completely avoid the deformation. By using the die casting machine of the present invention, a good casting product can be continuously obtained without producing defective products or burrs even if the mold apparatus has a precise configuration.

  Hereinafter, the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a schematic view showing an example of a movable mold and a fixed main mold, which are mold apparatuses in a die casting machine according to the present invention. In the die-casting machine according to the present invention, except for the configuration of a mold apparatus composed of a movable mold and a fixed main mold (fixed main mold configuration), other configurations are conventionally known as described with reference to FIG. Same as the die-casting machine. Therefore, in the following description, the mold apparatus will be mainly described and description of the entire die casting machine will be omitted.

  The basic configuration of the mold apparatus A shown in FIG. 1 is the same as the mold apparatus described with reference to FIG. 3, and is composed of a pair of fixed main mold 15 and movable mold 16, and the fixed main mold 15 is fixedly inserted. The movable die 16 is provided with a movable insert 42 and a slide core holder 43. Then, the slide core 44 is inserted into the slide core holder 43 to form the cavity 45. Of course, the configuration of the mold apparatus is an example, and the configuration of the mold apparatus used in the conventional die casting or injection molding is arbitrarily adopted as the mold apparatus of the present invention without being limited thereto. It is natural that we can do it.

  In the mold apparatus A of the present invention, a fitting member 46 made of the same material as that of the fixed main mold 15 is detachably attached in the vicinity of the corner portion of the contact surface of the slide core holder 43 in the fixed main mold 15. A strain gauge 47 is attached to the back surface of 46. A signal line 48 from the strain gauge 47 is connected to the control device 49. As described above, the mold apparatus A is mounted between the fixed platen 11 and the movable platen 14 of a conventionally known die casting machine, and is clamped in the cavity of the mold apparatus A by the mold clamping device. Molten metal or molten resin is press-fitted from the injection device 30. After cooling, the mold clamping device is operated to open the mold, and the cast product is taken out. In the apparatus shown in FIG. 2, the movable platen 14 is constituted by the toggle side member 14b and the mold side member 14a. However, when the mold apparatus A according to the present invention is used, this structure is unnecessary. It is.

  In the process of casting using the mold apparatus A according to the present invention, it is assumed that foreign matter is caught between the molds. In that case, as described with reference to FIG. 4, a sudden rise in stress occurs in the mold apparatus A. The rise of this stress is directly detected by the strain gauge 47 as strain generated in the fixed main mold 15, and the detection signal is sent to the control device 49. A certain set value (A) (see FIG. 4) is set as a threshold value in the control device 49. When the detected stress exceeds the set value (A), the control device 49 operates on the mold clamping device. Send a signal to stop. By setting the set value (A) to a value equal to or less than the elastic limit of the fixed main mold 15, the mold clamping can be reliably interrupted before the plastic deformation of the fixed main mold 15 occurs.

  In the mold apparatus A having the structure as shown in FIG. 1, distortion generated in the mold apparatus A is likely to occur first at the contact surface of the slide core holder 43 in the fixed main mold 15, particularly at the corner portion. It is effective to attach the strain gauge 47 to the position shown. Further, when the strain gauge 47 needs to be replaced for some reason, the fitting member 46 is removed from the fixed main mold 15 and the strain gauge 47 is replaced with a new one, and then attached to the fixed main mold 15 again. The strain gauge 47 may be directly attached to the fixed main mold 15 when it is not damaged by heat during casting. In this case, there is an advantage that the conventional fixed main mold can be used as it is.

Schematic which shows an example of the movable type | mold which is a metal mold | die apparatus in the die-casting machine by this invention, and a fixed main type | mold. Schematic which shows an example of the conventional die-casting machine. Schematic which shows an example of a metal mold apparatus. An example of the relationship between the stress generated in the fixed main mold at the time of casting and time is shown, curve A is normal, and curve B is a case where foreign matter is caught during mold clamping.

Explanation of symbols

A ... Mold apparatus according to the present invention, 15 ... Fixed main mold, 16 ... Movable mold, 41 ... Fixed insert, 42 ... Moveable insert, 43 ... Slide core holder, 44 ... Slide core, 45 ... Cavity, 46 ... Insertion Member 47 ... Strain gauge 48 ... Signal line 49 ... Control device

Claims (3)

  A mold device composed of a movable mold and a fixed main mold, a mold clamping apparatus that moves the movable mold toward the fixed main mold and performs mold clamping, and a molten metal or molten metal in the cavity space of the mold apparatus that has been clamped A die-casting machine having an injection device for press-fitting resin, and a mold clamping device when a strain gauge mounted on a fixed main mold and a value related to a strain amount obtained from the strain gauge exceeds a preset value And a control means for stopping the operation of the die casting machine.   The die casting machine according to claim 1, wherein the movable type includes a slide core holder, and the strain gauge is mounted near a corner portion of a contact surface of the fixed main type slide core holder.   The operation method of the die casting machine according to claim 1 or 2, wherein a stress value lower than a stress value at which plastic deformation occurs in the fixed main mold is set as a reference value, and a value related to a strain amount obtained from a strain gauge is the value described above. A method of operating a die casting machine, wherein clamping is stopped when a stress value that is a reference value is exceeded.

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