JP2019198975A - Injection molding die - Google Patents

Abstract

To provide an injection molding die capable of molding a resin molded article that is hardly influenced by heat from resin to be molded into a runner part.SOLUTION: A die 10 of this invention comprises: a fixed mold 40 including a cavity C and a runner L that feeds out molten resin to the cavity C; a movable mold 20 that is mold-closed to the fixed mold 40; a gate-forming member 60 disposed in a boundary part between the cavity C and runner L and forming a gate by moving in a direction approaching the movable mold 20; and a gate-cutting member 50 that protrudes from the movable mold 20 to the gate in a mold closing state and cuts a resin charged into the gate, or forms a groove of any depth in the resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an injection mold.

  The following Patent Document 1 describes a gate cutting device that takes out a resin molded product having sprue runners connected through a gate part from a molding die and then cuts the gate part.

JP-A-6-270210

  When the gate part is cut after being taken out from the molding die as in Patent Document 1, the resin molded product may be affected by heat from the resin forming the sprue runner before the gate part is cut. There is sex. Due to the influence of this heat, the resin molded product may be warped or change in dimensions.

  In view of the above facts, an object of the present invention is to provide an injection mold that can mold a resin molded product that is hardly affected by heat from the resin forming the runner portion.

  An injection mold according to the present invention as set forth in claim 1 includes a first mold including a cavity and a runner for sending a molten resin to the cavity, and a second mold clamped to the first mold. A gate forming member disposed at a boundary between the mold and the cavity and the runner and moving in a direction approaching the second mold to form a gate; and protruding from the second mold to the gate in a clamped state And a gate cut member that cuts the resin filled in the gate or forms a groove in the resin.

  According to the injection mold according to the first aspect of the present invention, the gate is formed at the boundary between the cavity of the first mold and the runner. The gate is formed by moving the gate forming member in a direction approaching the second mold. The gate formed by the gate forming member is filled with resin. The resin filled in the gate is cut by the gate cut member protruding from the second mold to the gate. When the resin filled in the gate is cut in a mold-clamped state, the heat of the resin filled in the runner is suppressed from being transmitted to the resin filled in the cavity.

  Or the groove | channel is formed in the resin with which the gate was filled, when a gate cut member protrudes from a 2nd type | mold to a gate. Even in this case, it is difficult to transfer the heat of the resin filled in the runner to the resin filled in the cavity as compared with the case where the groove is not formed.

  In the following description of the present specification, the resin filled in the gate is referred to as “gate resin”, the resin filled in the runner is referred to as “runner resin”, and the resin filled in the cavity is referred to as “molded product”. “Gate” and “runner” refer to a space formed in an injection mold.

  The injection mold according to the second aspect of the present invention is the injection mold according to the first aspect, wherein a pressing member that presses the gate cut member toward the gate, and And a control device for controlling the pressing speed.

  According to the injection mold according to the second aspect of the present invention, the gate cut member is pressed by the pressing member. The pressing speed of the pressing member is controlled by a control device. That is, the speed at which the gate cut member presses the gate resin is controlled. By adjusting the speed at which the gate resin is pressed, the occurrence of burrs or the like can be suppressed when the gate resin is cut.

  The injection mold according to the third aspect of the present invention is the injection mold according to the first or second aspect, wherein the cavity surface forms the cavity and the cavity surface in the second mold. A film material that is integrated with the resin can be installed on at least one of the facing surfaces that face each other.

  According to the injection mold according to the third aspect of the present invention, the film material can be disposed on the cavity surface or the opposed surface facing the cavity surface. For this reason, the film material is disposed on the surface of the molded product in a state of being integrated with the molded product.

  When a film is disposed on the surface of the molded product, heat is less likely to be released from the surface of the molded product as compared to a molded product in which no film is disposed. For this reason, the heat transmitted from the runner resin is hardly released to the outside from the molded product. However, in the injection mold according to the third aspect of the present invention, the heat of the runner resin is hardly transmitted to the molded product by the gate cut member. For this reason, inflow of heat can be suppressed and the amount of heat to be released can be reduced.

  The injection mold according to the fourth aspect of the present invention is the injection mold according to any one of the first to third aspects, wherein the runner is along the width direction of the cavity. It is formed in a planar shape.

  According to the injection mold according to the fourth aspect of the present invention, the runner is formed in a planar shape along the width direction of the cavity. For this reason, compared with the case where the runner is formed in a linear shape, the resin easily flows into the cavity, and a uniform molded product is easily obtained.

  In addition, by forming the runner in a planar shape, the amount of heat of the runner resin is increased, and heat is easily transmitted to the molded product. However, in the injection mold according to the fourth aspect of the present invention, the heat of the runner resin is hardly transmitted to the molded product by the gate cut member. For this reason, even if the heat quantity of runner resin increases, it can be made difficult to convey the heat quantity to a molded article.

  The injection mold according to the present invention has an excellent effect that a resin molded product that is hardly affected by heat from the resin forming the runner portion can be molded.

(A) is sectional drawing which shows an example of the metal mold | die for injection molding which concerns on embodiment of this invention, (B) is a BB arrow directional view in (A). It is sectional drawing which shows the state which clamped the movable mold | type and fixed mold | type in the injection mold which concerns on embodiment of this invention. (A) is sectional drawing which shows the state which formed the gate by the gate formation member in the injection die which concerns on embodiment of this invention, and inject | emitted molten resin, (B) is the elements on larger scale which show the state of a gate periphery It is sectional drawing. (A) is sectional drawing which shows the state which moved the gate formation member in the direction away from a movable mold | type after gate sealing in the injection mold which concerns on embodiment of this invention, (B) is a periphery of a gate. It is a partial expanded sectional view which shows a state. (A) is sectional drawing which shows the state which cut | disconnected gate resin by the gate cut member in the injection mold which concerns on embodiment of this invention, (B) is a partial expanded sectional view which shows the state of a gate periphery. is there. It is sectional drawing which shows the state which opened the movable mold | type and the fixed mold | type in the injection mold which concerns on embodiment of this invention. It is sectional drawing which shows the state which opened the movable mold | type and fixed mold in the injection mold which concerns on embodiment of this invention, and released the molded article.

(Injection mold)
As shown in FIGS. 1A and 1B, an injection mold according to an embodiment of the present invention (hereinafter referred to as “mold 10”) includes a movable mold 20 and a fixed mold 40. I have.

(Movable type)
The movable mold 20 includes a main body 22, two plates 24 and 26 installed inside the main body 22, and an ejector rod 28 that presses the plate 26 toward the fixed mold 40.

  The main body 22 is opposed to the fixed mold 40 and contacts the fixed mold 40 when the mold is clamped, a core 22B protruding from the parting surface 22A toward the fixed mold 40, and movable when the mold is clamped. And a guide pin 22C for positioning the mold 20 with respect to the fixed mold 40. A space 22V is formed inside the main body 22, and plates 24 and 26 are installed in the space 22V.

  The plate 24 is a metal plate disposed closer to the fixed mold 40 than the plate 26 in the space 22V, and the release pin 24A and the guide pin 24B are integrated.

  The release pin 24 </ b> A protrudes from the plate 24 toward the fixed mold 40 and is inserted into a through hole formed in the core portion 22 </ b> B of the main body portion 22. The tip surface of the release pin 24A and the core portion 22B are flush with each other except when the molded product CR (see FIG. 7) is released.

  The guide pin 24 </ b> B protrudes from the plate 24 toward the fixed mold 40 and is inserted into a through hole formed in the parting surface 22 </ b> A of the main body 22. The distal end surface of the guide pin 24B protrudes from the parting surface 22A toward the fixed mold 40.

  A coil spring 30A is wound around the guide pin 24B. The coil spring 30 </ b> A biases the plate 24 in a direction away from the fixed mold 40. The movement of the plate 24 biased by the coil spring 30 </ b> A in a direction away from the fixed mold 40 is restricted by contacting the stopper 30 </ b> B.

  In addition, in a state where the plate 24 is in contact with the stopper 30B, the tip surface of the release pin 24A and the core portion 22B are flush with each other. The stopper 30 </ b> B is a cylindrical member, is fixed to the main body 22, and is inserted into a through hole formed in the plate 26.

  The plate 26 is a metal plate disposed on the opposite side of the fixed mold 40 with respect to the plate 24 in the space 22V, and the gate cut member 50 and the guide pin 26B are integrated.

  The gate cut member 50 projects from the plate 26 toward the fixed mold 40 and is inserted into the through hole formed in the plate 24 and the through hole formed in the parting surface 22A in the vicinity of the core portion 22B in the main body portion 22. ing.

  The gate cut member 50 includes a base portion 52 that is inserted into the through hole of the plate 24, and a blade portion 54 that is disposed at the tip of the base portion 52 and is inserted into the through hole of the parting surface 22A. The blade portion 54 is formed using, for example, martensitic stainless steel.

  The guide pin 26 </ b> B protrudes from the plate 26 toward the fixed mold 40 and is inserted into a through hole formed in the plate 24 and a through hole formed in the parting surface 22 </ b> A of the main body 22. The distal end surface of the guide pin 26B protrudes from the parting surface 22A toward the fixed mold 40.

  A coil spring 32A is wound around the guide pin 26B. The coil spring 32 </ b> A biases the plate 26 in the direction away from the fixed mold 40. The movement of the plate 26 biased by the coil spring 32 </ b> A in the direction away from the fixed mold 40 is restricted by contacting the stopper 32 </ b> B. The stopper 32 </ b> B is a cylindrical member and is fixed to the main body 22.

  The ejector rod 28 is a pressing member that can be inserted into a through hole formed in the main body portion 22 on the side opposite to the side on which the core portion 22B is formed. The ejector rod 28 moves in a direction approaching the fixed mold 40 and presses the plate 26. The plate 26 moves in the direction of the fixed mold 40 against the urging force of the coil spring 32A. Then, it abuts against the spacer 34 </ b> B installed on the plate 24 and presses the plate 24. The plate 24 moves in the direction of the fixed mold 40 against the urging force of the coil spring 30A. And it contacts the spacer 34A installed in the main body 22 and stops moving.

  A control device 28A is electrically connected to the ejector rod 28. The control device 28 </ b> A can control the stroke and the pressing speed of the ejector rod 28.

(Fixed type)
The fixed mold 40 includes a front mold 42 and a rear mold 44. The front mold 42 is formed with a cavity portion 42A, a runner portion 42B, and a spool portion 42C. The cavity portion 42 </ b> A is a recess formed in the parting surface 42 </ b> D, and is recessed in a direction away from the movable mold 20.

  The runner part 42B is a supply path for allowing the molten resin injected from the spool part 42C to flow into the cavity part 42A, and extends along the width direction of the cavity part 42A as shown by a two-dot chain line in FIG. It is formed in a planar shape.

  Guide holes 42E, 42F, and 42G are formed in the parting surface 42D at positions corresponding to the guide pins 24B, 26B, and 22C of the movable mold 20, respectively. Thereby, the release pin 24 </ b> A, the gate cut member 50, and the movable die 20 are aligned at predetermined positions with respect to the fixed die 40. The guide hole 42G is a through hole.

  The rear mold 44 is disposed behind the front mold 42 as viewed from the movable mold 20 and is formed to be movable relative to the front mold 42. The rear mold 44 is provided with guide pins 44A. The guide pin 44A is inserted from the opening end opposite to the opening end into which the guide pin 22C is inserted in the guide hole 42G, and is aligned with the front mold 42.

  The front mold 42 and the rear mold 44 are urged away from each other by the coil spring 36. The front mold 42 and the rear mold 44 move in a relatively approaching direction as the movable mold 20 and the fixed mold 40 are clamped.

  The rear mold 44 is formed with a gate forming member 60 (a leading plate) that protrudes toward the movable mold 20. The gate forming member 60 is inserted into a through hole formed in the front mold 42. The gate forming member 60 is disposed at a boundary portion between the cavity portion 42A and the runner portion 42B. Further, the gate forming member 60 is disposed at a position facing the gate cut member 50. In the state where the front mold 42 and the rear mold 44 shown in FIGS. 3 (A) and 3 (B) move in a relatively close direction and contact each other, the boundary between the runner L and the cavity C is formed by the gate forming member 60. A gate G is formed in the portion.

(Method for manufacturing molded products)
An example of a method for producing a molded product CR (see FIG. 7) using the mold 10 according to the embodiment of the present invention will be described. In order to obtain the molded product CR, first, the movable mold 20 is moved from the state shown in FIG. 1 (A) in the direction of approaching the fixed mold 40 and clamped, and the state shown in FIG. To do.

  At this time, the movable pin 20 is positioned with respect to the fixed die 40 by fitting the guide pin 22C into the guide hole 42G. A chamfer (R surface or C surface) is formed at the tip of the guide pin 22C, and serves as a guide portion for introducing the guide pin 22C into the guide hole 42G.

  With the parting surface 22A of the movable mold 20 and the parting surface 42D of the front mold 42 in the fixed mold 40 in surface contact, the distal ends of the movable guide pins 24B and 26B are guided holes 42E and 42F, respectively. Inserted.

  In this state, a runner L that is a space filled with molten resin is formed between the parting surface 22A of the movable mold 20 and the runner portion 42B of the fixed mold 40. A cavity C, which is a space filled with a molten resin, is formed between the core portion 22B of the movable mold 20 and the cavity portion of the fixed mold 40.

  In this specification, “cavity portion 42A”, “runner portion 42B” and “spool portion 42C” are names of portions formed in the fixed mold 40, and “cavity C”, “runner L” and “ “Spool S” indicates a space formed by “cavity portion 42A”, “runner portion 42B” and “spool portion 42C”. Further, the resins filled in “cavity C”, “runner L”, and “spool S” are referred to as “molded product CR”, “runner resin LR”, and “spool resin SR”, respectively.

  Next, as shown in FIG. 3A, the rear mold 44 of the fixed mold 40 is brought closer to the front mold 42 (or the movable mold 20 and the front mold 42 are brought closer to the rear mold 44), and the gate forming member 60 is moved. Is moved in the direction of the movable mold 20. As a result, a gate G is formed at the boundary between the runner L and the cavity C, as shown in FIG. In a state where the gate G is formed, the molten resin is injected from the spool S to the runner L, whereby the cavity C is filled with the molten resin.

  After the resin of the gate G (gate resin GR) has stopped solidifying and flowing (gate sealing), the movable mold 20 and the front mold 42 are moved away from the rear mold 44 as shown in FIG. The forming member 60 is moved away from the movable mold 20. Thereby, as shown in FIG. 4B, a space V is formed between the gate resin GR and the gate forming member 60 (behind the gate resin GR as viewed from the movable mold 20).

  In a state where the space V is formed, the ejector rod 28 is advanced toward the fixed mold 40 to press the plate 26. Thereby, as shown in FIG. 5A, the plate 26 and the gate cut member 50 fixed to the plate 26 move toward the fixed mold 40. As shown in FIG. 5B, the blade portion 54 of the gate cut member 50 is inserted into the space V by cutting the gate resin GR. The shape of the blade portion 54 is arbitrary, but in FIG. 5B, the shape of the molded product CR is an acute angle.

  At this time, the control device 28 </ b> A adjusts the pressing speed at which the ejector rod 28 presses the plate 26. For example, with respect to the thickness T of the gate resin GR, the cutting length of the blade portion 54 with respect to the gate resin GR is cut at a low speed from 0 to 0.25T, and the cutting speed is increased from 0.25T to 0.75T. The pressing speed is adjusted so as to cut again at a low speed above 0.75T. Thereby, it can suppress that a burr | flash generate | occur | produces in molded article CR.

  The control device 28A can adjust the pressing force according to the hardness of the resin. For example, the pressing force is increased for a hard resin, and the pressing force is decreased for a soft resin. Thereby, resin of various hardness can be cut | disconnected.

  Note that “cut the gate resin GR” means that the gate resin GR is removed from the molded product CR and the runner resin LR and the molded product CR and the runner resin LR are divided as shown in FIG. In addition to the embodiment, an embodiment in which the gate resin GR is left as a burr on at least one of the molded product CR and the runner resin LR is also included.

  Further, the adjustment of the pressing speed by the control device 28A in the present invention includes a case where the plate 26 is pressed at a constant speed, for example. That is, as long as the pressing speed can be adjusted according to the hardness of the resin, pressing may be performed at an equal pressing speed from the start to the end of cutting. Further, in the present invention, the control device 28A is not essential, and for example, an operator may manually operate the ejector rod 28.

  Next, as shown in FIG. 6, the movable mold 20 is removed from the fixed mold 40 (the mold is opened). At this time, the movable mold 20 and the ejector rod 28 are moved in the direction away from the fixed mold 40 by the same stroke.

  The ejector rod 28 may be moved in a direction away from the fixed mold 40 prior to the movement of the movable mold 20 (prior to mold opening). That is, the ejector rod 28 can be moved independently of the movable mold 20.

  Furthermore, by pushing the ejector rod 28 in the direction of the fixed mold 40 in a state where the mold is opened, the plate 26 presses the plate 24 via the spacer 34A as shown in FIG. Thus, the release pin 24A integrated with the plate 24 protrudes from the core portion 22B, and the molded product CR is released from the movable die 20. Further, the runner resin LR and the spool resin SR are removed from the molded product CR. In this way, the molded product CR can be obtained.

(Action / Effect)
According to the mold 10 according to the embodiment of the present invention, the gate G is formed at the boundary between the cavity C and the runner L of the fixed mold 40 as shown in FIGS. The gate G is formed by moving the gate forming member 60 in a direction approaching the movable mold 20. The gate G formed by the gate forming member 60 is filled with molten resin. The gate resin GR is cut by the gate cut member 50 protruding from the movable mold 20 after the solidification flow stop (gate seal).

  By cutting the gate resin GR in the clamped state, the heat of the runner resin LR is suppressed from being transferred to the molded product CR as compared with the case of cutting after the mold opening.

  Further, the gate forming member 60 can move in a direction away from the movable mold 20. As shown in FIGS. 5A and 5B, after the gate resin GR resinized on the gate G is solidified and stopped (gate seal), the gate forming member 60 is moved away from the movable mold 20. A space V is formed on the back side of the gate resin GR when viewed from the movable mold 20. Accordingly, when the gate resin GR is cut by the gate cut member 50, the tip of the gate cut member 50 can be pushed to the rear of the gate resin GR. For this reason, it is easy to cut the gate resin GR.

  Further, according to the mold 10 according to the embodiment of the present invention, the gate cut member 50 is pressed by the ejector rod 28 via the plate 26. The ejector rod 28 has a pressing speed controlled by a control device 28A. That is, the speed at which the gate cut member 50 presses the gate resin GR is controlled. By adjusting the speed at which the gate resin GR is pressed, generation of burrs or the like can be suppressed when the gate resin GR is cut.

  Moreover, in the metal mold | die 10 which concerns on embodiment of this invention, as shown to FIG. 1 (B), the runner part 42B is formed in planar shape along the width direction of the cavity part 42A. For this reason, compared with the case where runner part 42B is formed in the shape of a line, resin flows easily into cavity C, and it is easy to obtain uniform molded product CR.

  In addition, by forming the runner part 42B in a planar shape, the amount of heat of the runner resin LR is increased as compared with the case of forming the runner part 42B in a linear shape, and heat is easily transmitted to the molded product CR. However, in the mold 10 according to the embodiment of the present invention, since the gate resin GR between the molded product CR and the runner resin LR is cut by the gate cut member 50, the heat of the runner resin LR is not easily transmitted to the molded product CR. Has been. For this reason, even if the calorie | heat amount of runner resin LR increases, it can be made difficult to convey it to the molded product CR.

  Further, in the mold 10 according to the embodiment of the present invention, the gate forming member 60 moves in the direction approaching the movable mold 20 to form the gate G. By adjusting the proximity stroke, the gate G is formed. Any thickness can be formed. In order to adjust the proximity stroke, for example, a spacer may be sandwiched between the front mold 42 and the rear mold 44 of the fixed mold 40. If the gate G is formed thick, the resin can easily flow from the runner L to the cavity C. If the gate G is formed thin, the influence of heat from the runner resin LR to the molded product CR can be reduced.

  In the present embodiment, as shown in FIGS. 5A and 5B, the gate resin GR is cut by the gate cut member 50, but the embodiment of the present invention is not limited to this. For example, a groove may be formed in the gate resin GR by the gate cut member 50. In order to form a groove in the gate resin GR by the gate cut member 50, for example, the spacer 34B is formed thick and the stroke of the gate cut member 50 is adjusted (shortened). Alternatively, the length of the blade portion 54 of the gate cut member 50 is adjusted (shortened) so that the blade portion 54 does not reach the space V.

  Thus, in this invention, since the movable mold | type 20 and the gate cut member 50 can be moved independently, respectively, a gate cut can be carried out by arbitrary methods. Even when the groove is formed in the gate resin GR, it is possible to suppress the heat of the runner resin LR from being transmitted to the molded product CR as compared with the case where the groove is not formed.

  Further, when the mold is released with the groove formed in the gate resin GR, the state in which the molded product CR, the gate resin GR, the runner resin LR, and the spool resin SR are integrated is maintained at the time of release. The end materials (gate resin GR, runner resin LR, and spool resin SR) are not easily scattered around the periphery of. Thereby, production management efficiency can be improved. When the molded product CR and the runner resin LR are separated, they can be easily separated by applying a bending moment to the portion where the groove is formed.

  In the present embodiment, as shown in FIGS. 4A, 4B, 5A, and 5B, the gate forming member 60 is moved away from the movable mold 20, and the space V is formed. Although the gate resin GR is cut by the gate cut member 50 after the formation, the embodiment of the present invention is not limited to this.

  For example, from the state shown in FIGS. 3A and 3B, the plate 26 in the movable mold 20 is moved in a direction approaching the fixed mold 40 to cause the gate cut member 50 to enter the gate resin GR, while the gate The forming member 60 may not be moved. In this case, a reaction force can be obtained from the gate forming member 60 when the gate resin GR is pressed by the gate cut member 50. Thereby, it becomes easy to cut | disconnect resin with high hardness.

  Further, in the present embodiment, the surface of the molded product CR is not decorated, but the embodiment of the present invention is not limited to this. For example, a decorative resin film formed into a shape along the cavity portion 42 </ b> A may be installed along the cavity portion 42 </ b> A of the fixed die 40 before mold clamping. Arbitrary designs etc. can be printed on this resin film for decorating. In addition, the decorative resin film may be disposed along the core portion 22B of the movable mold 20. These decorative resin films are integrated with the resin filled in the cavity C. Thereby, the molded product CR with the decorated surface can be obtained.

  As described above, when the decorative resin film is disposed on the surface of the molded product CR, it is difficult to release heat from the surface of the molded product CR as compared to the molded product CR in which the decorative resin film is not disposed. Further, deformation or the like may occur due to the influence of high-temperature heat in the runner resin LR. However, in the embodiment of the present invention, the gate cut member 50 cuts the gate resin GR between the molded product CR and the runner resin LR, or forms a groove in the gate resin GR, so that the heat of the runner resin LR is molded. It is difficult to convey to the product CR. That is, the amount of heat to be released can be reduced by suppressing the inflow of heat. In addition, even if it replaces with the electrode film etc. with which the electrode material was arrange | positioned, for example, this decorating film can acquire the same effect. As described above, the present invention can be implemented in various modes.

10 Mold (mold for injection molding)
20 Movable type (second type)
22B Core part (opposite surface facing the cavity surface)
28 Ejector rod (pressing member)
28A Control device 40 Fixed type (first type)
42A Cavity (cavity surface)
50 Gate cut member 60 Gate forming member C Cavity L Runner G Gate

Claims (4)

A first mold comprising a cavity and a runner for delivering molten resin to the cavity;
A second mold clamped to the first mold;
A gate forming member that is disposed at a boundary between the cavity and the runner and moves in a direction approaching the second mold to form a gate;
A gate cut member that projects from the second mold to the gate in a clamped state and cuts the resin filled in the gate or forms a groove in the resin;
Mold for injection molding. A pressing member that presses the gate cut member toward the gate;
A control device for controlling the pressing speed of the pressing member;
The injection mold according to claim 1, comprising: A film material integrated with the resin can be installed on at least one of a cavity surface forming the cavity and a facing surface facing the cavity surface in the second mold.
The injection mold according to claim 1 or 2. The runner is formed in a planar shape along the width direction of the cavity.
The injection mold according to any one of claims 1 to 3.