JPH0760809A - Method and machine for locally pressurizing type injection molding - Google Patents

Abstract

PURPOSE:To sufficiently push resin in the side wall part of a cavity at the molding of a box-shaped molding article. CONSTITUTION:The injection molder concerned has a stationary mold, a movable mold, which is arranged so as to attach to and detach from the stationary mold in order to form a cavity 212 between both the molds, pressurizing pins 352, each of which extends so as to penetrate the movable mold and face its side to the rising part of the cavity 212 and its tip to a ceiling wall part 212a and at the front of each of which a false boss part 212c is formed, and a driving means for advancing the pressurizing pin 352. Accordingly, by advancing the pressurizing pins 352, the resin in the dispensable boss part 212c is sufficiently pushed in the ceiling wall part and the rising part. As a result, neither sinkmark nor warpage develops at the side wall parts 212b of a molded article and no inward warpage at the side wall corner part 212 develops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local pressure injection molding method and a local pressure injection molding machine.

[0002]

2. Description of the Related Art Conventionally, in a local pressure type injection molding machine, a tip of an ejector pin is made to face a cavity, a tip of the pressure pin is made to face a processed part of the molded article, and the ejector pin is moved forward to advance the molded article. Then, the molded product can be processed by pushing down and pushing the pressure pin forward.

FIG. 2 is a sectional view of a conventional local pressure injection molding machine. In the figure, 11 is a fixed side attachment plate, and the fixed mold 12 is attached to a fixed platen (not shown) via the fixed side attachment plate 11. Then, the injection nozzle of the injection device (not shown) advances in the injection process, and the tip of the injection nozzle is brought into contact with the sprue bush 13 of the fixed mold 12.

On the other hand, a movable platen (not shown) is moved forward and backward (moved in the left-right direction in the figure) by a mold clamping device (not shown) to bring the movable mold 14 into and out of contact with the fixed mold 12. Therefore, the movable mold 14 is attached to the movable platen via the movable side mounting plate 15 and a spacer block (not shown). Then, the resin injected from the injection nozzle passes through the sprue 18 and the runner 19, and is filled (sufficiently) into the cavity 21 formed between the fixed mold 12 and the movable mold 14 via the gate 20.

When the injection process is completed, a pressure-holding process is subsequently performed, the resin pressure in the cavity 21 is maintained, and the resin starts to be cooled. After a certain period of time, a molded product (not shown) is left on the movable mold 14 side. In this state, the two molds 12 and 14 are opened, and the molded product is pushed down by the ejector device. Therefore, the sprue lock pin 25 and the ejector pin 26 are provided. The sprue lock pin 25 is disposed so as to face the sprue 18, and holds a molded product when the mold is opened and leaves it on the movable mold 14 side. The ejector pin 26 is disposed with its tip facing the cavity 21, the runner 19, etc., and the molded product is moved to the movable mold 1 after the mold is opened.
Separate from 4 and push down.

The sprue lock pin 25 and the ejector pin 26 penetrate the movable mold 14 and extend rearward (to the left in the figure), and the head portion formed at the rear end is held by ejector plates 51 and 52. Fixed. Then, the rod 23 can be brought into contact with the ejector plate 51, and the sprue lock pin 25 and the ejector pin 26 are advanced as the rod 23 moves forward.

By the way, a pressure pin 35 is provided in order to process the molded product during the pressure-holding step. The pressurizing pins 35 are arranged in a required number such that the tips thereof face predetermined positions such as the cavity 21 and the gate 20, and extend through the movable mold 14 and the ejector plates 51 and 52 to the rear side. The head portion formed at the end is clamped and fixed by the pressure plates 36 and 37.

The pressure plates 36 and 37 are disposed so as to be able to come into contact with and separate from the movable side mounting plate 15, and are moved forward and backward by two pressure cylinders 41. That is, the piston rod 42 of the pressurizing cylinder 41 has the crosshead 53
The pressure rod 54 is fixed to the cross head 53. The pressure rod 54 is attached to the movable side mounting plate 1
The pressure pin 35 can be pushed out by penetrating the pressure plate 35 and coming into contact with the pressure plate 36.

The hydraulic pressure supplied to the pressurizing cylinder 41 is controlled by a proportional pressure reducing valve or a servo valve (not shown). By electrically controlling the proportional pressure reducing valve or the servo valve, the pressurizing pin 35 is gradually advanced while vibrating to apply a pulse-like pressure force to the resin of the processed portion of the molded product to excite (displace). Then, the molded product can be subjected to predetermined processing.

Even if the pressurizing pin 35 is moved forward by using the proportional pressure reducing valve or the servo valve, the resin cannot be excited. Further, a reaction force is required to excite the resin by the applied pressure, and the pressure pin 35 must be forcibly retracted from the processing portion. Therefore, a highly responsive return spring 40 that surrounds the four return pins 38 is provided between the pressure plate 37 and the movable mold 14. The pressure pin 35 and the return pin 38 both have a head portion formed at their rear ends.
The head portion is sandwiched and fixed by the pressure plates 36 and 37. In this case, four return springs 40
By uniformly arranging the pressure plates 36, 3
7 can be moved in parallel without tilting, and a smooth operation can be obtained.

As described above, the molded product can be processed by advancing the pressure pin 35, and at the same time, the waste boss portion formed in front of the pressure pin 35 (right side in the drawing) is formed. Since the resin is pushed into the cavity 21, it is possible to prevent sink marks and warpage from occurring in the molded product.

[0012]

However, in the above-mentioned conventional local pressure type injection molding machine, both molds 12, 1 are used.
Since the pressure pin 35 disposed in the direction perpendicular to the parting surface of 4 is advanced to process the molded product, it is sufficient to mold the molded product of the box. A large amount of resin cannot be pushed into the side wall of the cavity 21.

FIG. 3 is a view showing a state inside a cavity when a box-shaped molded product is molded by a conventional local pressure type injection molding machine. (A) of the figure is a plan view of the cavity, and (b) is a side view of the cavity. In the figure, 19 is a runner,
201 is a side gate, 211 is a cavity, 21
Reference numeral 1a is a fillet portion of the cavity 211, 211b is a side wall portion of the cavity 211, 211c is a discarding boss portion formed in front of the pressing pin 351 (right side in the drawing), 21
1d is a side wall corner.

In this case, the resin of the waste boss portion 211c is moved to the cavity 2 by advancing the pressure pin 351.
11 is pushed into the cavity 211 and the fillet portion 211 of the cavity 211
The pressure of a rises. However, if the fillet portion 211a is thin, the resin pushed into the cavity 211 may have side walls 2
It does not reach 11b, and the acupressure of the above-mentioned fillet part 211a does not diffuse. Therefore, sink marks or warpage may occur in the side wall portion of the molded product (not shown), and inward warpage may occur in the side wall corner portions.

FIG. 4 is a view showing a molding state of a conventional box-shaped molded product. In the figure, 61 is a molded product, 61c is a side wall of the molded product 61, and 61d is a side wall corner of the molded product 61. In this case, the left half of the figure shows a good product, and the right half shows a defective product. In the case of a defective product, the side wall corner 6 of the molded product 61
An inner warp indicated by an angle α occurs in 1d.

The present invention solves the problems of the local pressure type injection molding machine, and in the case of molding a box-shaped molded product, the resin can be sufficiently pushed into the side wall of the cavity. It is an object of the present invention to provide a local pressurization injection molding method and a local pressurization injection molding machine in which sink marks and warps are not generated in the side wall portion and inward warp is not generated in the side wall corner portion.

[0017]

Therefore, in the local pressure injection molding method of the present invention, resin is filled in the cavity and the discarding boss while the pressure pin is retracted, and the pressure pin is moved forward. Then, the resin in the waste boss portion is directly pushed into the rising portion of the cavity. In the local pressurization type injection molding machine of the present invention, a fixed mold, a movable mold which is disposed so as to be able to come into contact with and separate from the fixed mold, and forms a cavity between the fixed mold, and a penetrating the movable mold. It has a pressure pin that extends and faces the rising portion of the cavity with its side surface facing the top of the fillet portion and forms a discarding boss portion in the front, and a driving means for moving the pressure pin forward.

In another local pressure type injection molding machine of the present invention, a fixed mold and a fixed mold are disposed so as to be able to come into contact with and separate from the fixed mold.
It has a movable die which forms a cavity between them, and a pressure pin which is arranged in the movable die so as to be movable back and forth.
A pressurizing block is disposed so that the pressurizing surface faces the rising portion of the cavity, and the pressurizing block is moved as the pressurizing pin moves back and forth.

[0019]

According to the present invention, as described above, in the local pressure type injection molding method, resin is filled in the cavity and the discarding boss with the pressure pin retracted, and the pressure pin is moved forward. The resin in the waste boss portion is directly pushed into the rising portion of the cavity. Therefore, even if the top portion of the cavity is thin, the resin in the waste boss portion can be sufficiently pushed into the rising portion.

In the local pressure type injection molding machine of the present invention, a fixed mold, a movable mold which is disposed so as to be capable of coming into contact with and separated from the fixed mold, and which forms a cavity therebetween, and the movable mold. Extends through to make the side face the rising part of the cavity,
The pressure pin has a tip facing the fillet portion and a discarding boss is formed in the front, and a drive unit for moving the pressure pin forward.

Therefore, by advancing the pressure pin, the resin in the waste boss portion can be sufficiently pushed into the fillet portion and the rising portion. In another local pressure type injection molding machine of the present invention, a fixed mold, a movable mold which is disposed so as to be contactable with and separable from the fixed mold, and forms a cavity between the fixed mold, and the movable mold in the movable mold. And a pressure pin arranged so as to be movable back and forth. A pressurizing block is disposed so that the pressurizing surface faces the rising portion of the cavity, and the pressurizing block is moved as the pressurizing pin moves back and forth.

Therefore, the pressure block is moved by advancing the pressure pin, so that the resin in the waste boss portion can be sufficiently pushed into the fillet portion and the rising portion.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a view showing a state inside a cavity in a first embodiment of the present invention, and FIG. 5 is a sectional view of a local pressure type injection molding machine to which the first embodiment of the present invention is applied. 1A is a plan view of the cavity, and FIG. 1B is a side view of the cavity.

In the drawing, 11 is a fixed side mounting plate,
The fixed mold 12 is attached to a fixed platen (not shown) through the fixed side mounting plate 11. Then, the injection nozzle of the injection device (not shown) advances in the injection process, and the tip of the injection nozzle is brought into contact with the sprue bush 13 of the fixed mold 12. On the other hand, the movable platen (not shown) is moved back and forth (moved in the left-right direction in the figure) by a mold clamping device (not shown) to bring the movable mold 14 into and out of contact with the fixed mold 12. Therefore, the movable mold 14 is attached to the movable platen via the movable side mounting plate 15 and a spacer block (not shown).

The resin injected from the injection nozzle passes from the sprue 18 to the runner 19 and then to the gate 20.
A cavity 212 formed between the fixed mold 12 and the movable mold 14 is filled with the mold 2 through When the injection process is completed, a pressure holding process is subsequently performed, and the resin pressure in the cavity 212 is maintained and the resin is started to be cooled. After a certain period of time, a molded product (not shown) is left on the movable mold 14 side. Both molds 12 and 14 are opened, and the molded product is pushed down by the ejector device.

Therefore, the sprue lock pin 252 and the ejector pin 262 are provided. The sprue lock pin 252 is disposed to face the sprue 18,
When the mold is opened, the molded product is held and left on the movable mold 14 side. Further, the ejector pin 262 is disposed with its tip facing the fillet portion 212a of the cavity 212, the runner 19, etc., and separates the molded product from the movable mold 14 after the mold is opened, and knocks it down.

Further, a pressure pin 352 is provided for processing the molded product during the pressure holding step. The pressure pin 352 extends along the side wall corner portion 212d as the rising portion of the cavity 212, and the side wall corner portion 2d.
12d is provided with a side face and the top portion 212a is provided with its tip facing the tip, and a necessary number of bosses 212c are formed in the front (right side in the drawing). And the pressure pin 3
52 moves forward to push the resin in the waste boss portion 212c into the fillet portion 212a and the side wall corner portion 212d. It is also possible to use the side wall portion 212b as the rising portion of the cavity 212 and dispose the pressure pin 352 along the side wall portion 212b.

By the way, the sprue lock pin 252.
The ejector pin 262 penetrates the movable mold 14 and extends rearward (leftward in the drawing), and the stepped portions 252a and 262a formed at the rear end portion are formed between the pressure plates 36 and 37. It is accommodated in the stepped portion accommodation chamber 38 and is movably arranged. Then, the stepped portions 252a, 26
Rear pin portions 252b and 262b are formed behind the pressure plate 37 and project through the pressure plate 37. Here, the depth of the stepped portion accommodating chamber 38 is equal to the depth of the stepped portion 252.
A value is larger than the thickness of a and 262a, and a play is formed.

On the other hand, the pressure pin 352 penetrates the movable mold 14 and the pressure plates 36 and 37 and extends rearward, and the head portion 352a formed at the rear end is clamped by the pressure plates 36 and 37. And fixed. The pressure plates 36 and 37 are disposed so as to come into contact with and separate from the movable side mounting plate 15, and are moved forward and backward by a pressure cylinder (not shown). The hydraulic pressure supplied to the pressurizing cylinder is controlled by a proportional pressure reducing valve or a servo valve (not shown). By electrically controlling the proportional pressure reducing valve or the servo valve, the pressurizing pin 352 is gradually advanced while vibrating to apply a pulsed pressure force to the resin of the processed portion of the molded product to excite (displace). Then, the molded product can be subjected to predetermined processing.

In the local pressure injection molding machine having the above-mentioned structure, the resin injected from the injection nozzle is sprue 1
8 enters the runner 19, and the runner 19 passes through the gate 202 to fill the cavity 212 formed between the fixed mold 12 and the movable mold 14. At this time, the waste boss portion 212c is also filled with the resin. Then, in the pressure-holding step after the resin has been filled in the cavity 212, the pressure cylinder operates and the pressure plate 3
Advancement of 6,37 is started.

When the pressure plates 36 and 37 start to move forward, the pressure pin 352 also starts to move forward to push the resin in the waste boss portion 212c into the fillet portion 212a and the side wall corner portion 212d. Therefore, not only the fillet portion 212a but also a sufficient amount of resin is pushed into the side wall corners 212d and 212b, so that a sink mark or a warp occurs on the side wall of the molded product, or an inward warp occurs on the side wall corner. Can be prevented.

When the pressure plates 36 and 37 advance and stop by the effective stroke of the pressure pin 352,
The pressurizing pin 352 is also stopped and the pushing of the resin is completed.
On the other hand, the pressure plates 36 and 37 are movable side mounting plates 15
When it is in the initial position where it abuts on the sprue lock pin 2
52 and the rear pin portion 252b of the ejector pin 262,
262b is pressed by the movable side mounting plate 15 to move forward, and the stepped portions 252a and 262a are also located at the front position in the stepped portion accommodation chamber 38. When the pressurizing cylinder operates and the pressurizing plates 36 and 37 move forward away from the movable side mounting plate 15, the sprue lock pin 252 and the ejector pin 262 move to the stepped portion 252a.
The stop state is maintained until 262a moves backward in the stepped portion accommodation chamber 38 by the play amount.

In this case, the effective stroke of the pressure pin 352 and the play of the sprue lock pin 252 and the ejector pin 262 are set to be equal. Therefore, when the pressure plates 36 and 37 advance and stop by the effective stroke of the pressure pin 352, they stop.
a and 262a relatively move backward in the stepped portion accommodation chamber 38 by the amount of the play and stop.

Subsequently, after a certain period of time, the molds 12 and 14 are opened with a molded product (not shown) left on the movable mold 14 side, and the pressure cylinder is operated to operate the pressure plate 3
Advance 6, 37 again. Along with this, the sprue lock pin 252 and the ejector pin 262 start moving forward again, and the molded product is pushed down by the sprue lock pin 252 and the ejector pin 262.

Next, a second embodiment of the present invention will be described. FIG. 6 is a sectional view of a local pressure type injection molding machine to which the second embodiment of the present invention is applied. In the figure, 11 is a fixed side attachment plate, and the fixed mold 12 is attached to a fixed platen (not shown) via the fixed side attachment plate 11. Then, the injection nozzle of the injection device (not shown) advances in the injection process, and the tip of the injection nozzle is brought into contact with the sprue bush 13 of the fixed mold 12.

On the other hand, a movable platen (not shown) is moved forward and backward (moved in the left-right direction in the drawing) to bring the movable mold 14 into contact with and separate from the fixed mold 12. Then, the resin injected from the injection nozzle passes from the sprue 18 to the runner 19,
The cavity 212 formed between the fixed mold 12 and the movable mold 14 is filled via the gate 202.

When the injection step is completed, a pressure holding step is subsequently carried out, the resin pressure in the cavity 212 is maintained, and the resin is started to be cooled.
Both molds 12, 14 with a molded product not shown left on the side
Is opened and the molded article is pushed down by the ejector device. Therefore, the sprue lock pin 253 and the ejector pin 263 are arranged. The ejector pin 26
3 is the fillet portion 212a of the cavity 212 and the runner 19
The mold is separated from the movable mold 14 and pushed down after the mold is opened.

A pressure pin 352 is provided to process the molded product during the pressure holding step.
The pressurizing pins 352 extend along side wall corners (not shown) as rising portions of the cavities 212, and are arranged in a required number such that the side surfaces are facing the side wall corners and the top portion 212a is facing the tip. And then throw it away (to the right in the figure) to the boss 2
12c is formed. Then, the pressure pin 352 moves forward to remove the resin in the waste boss portion 212c from the fillet portion 212.
Push it into a and push it into the side wall corner. The pressure pin 352 may be arranged along the side wall portion 212b.

By the way, the sprue lock pin 253.
The ejector pin 263 penetrates the movable mold 14 and extends rearward (leftward in the drawing), and the head portions 253a and 263a formed at the rear ends of the ejector plate 62 and the ejector plate 62, respectively.
It is clamped and fixed by 63. Then, the ejector plates 62 and 63 are moved forward and backward by an ejector cylinder (not shown). The hydraulic pressure supplied to the ejector cylinder is controlled by a proportional pressure reducing valve or a servo valve (not shown). By electrically controlling the proportional pressure reducing valve or the servo valve, the ejector pin 263 can be advanced and the molded product can be pushed down.

On the other hand, the pressure plates 363, 373 are disposed so as to be able to come into contact with and separate from the movable side mounting plate 15, and are moved forward and backward by a pressure cylinder (not shown). The hydraulic pressure supplied to the pressurizing cylinder is controlled by a proportional pressure reducing valve or a servo valve (not shown). By electrically controlling the proportional pressure reducing valve or the servo valve, the pressurizing pin 352 is gradually advanced while vibrating to apply a pulsed pressure force to the resin of the processed portion of the molded product to excite (displace). Then, the molded product can be subjected to predetermined processing.

In this case, the sprue lock pin 253 and the ejector pin 263 are connected by an ejector cylinder.
Further, the pressurizing pin 352 can be moved forward by the pressurizing cylinder at arbitrary timing and with arbitrary pressing force. 352a is a head portion of the pressure pin 352. Next, a third embodiment of the present invention will be described.

FIG. 7 is a view showing a state inside the cavity in the third embodiment of the present invention. (A) of the figure is a plan view of the cavity, and (b) is a side view of the cavity. In the figure, 19 is a runner, 202 is a side type gate, 2
14 is a cavity, 214 a is a fillet portion of the cavity 214, 214 b is a side wall portion of the cavity 214, 21
4c is a waste boss portion formed in front of the pressure pin 354 (right side in the drawing), 214d is a side wall corner portion as a rising portion of the cavity 214, 214e is between the waste boss portion 214c and the side wall portion 214b. It is a formed rib portion.

In this case, the discarding boss portion 214c and the side wall portion 2
Since the rib portion 214e is formed between 14b, the position where the pressure pin 354 is arranged is not limited. Next, a fourth embodiment of the present invention will be described. FIG. 8 is a diagram showing a state inside the cavity in the fourth embodiment of the present invention. (A) of the figure is a plan view of the cavity, and (b) is a side view of the cavity.

In the figure, 19 is a runner, 68 is a pressure block, 202 is a side type gate, 215 is a cavity, 215a is a fillet portion of the cavity 215, 215b.
Is a side wall portion of the cavity 215, 215c is a waste boss portion formed on the side wall portion 215b, 215d is a side wall corner portion as a rising portion of the cavity 215, and 355 is a pressure pin.

The discarding boss portion 215c and the pressure pin 355
In between, the pressure block 68 is disposed with the pressure surface facing the waste boss 215c. The pressure block 68
A taper surface facing each other is formed on the back surface of the pressurizing pin 355 and the side surface of the pressurizing pin 355. Then, in the injection step, the pressure pin 355 is retracted, and when the resin is filled in the cavity 215, the pressure block 68 is pushed toward the pressure pin 355 side by the resin pressure, and the discard boss is discharged. The portion 215c is formed, and the waste boss portion 215c is filled with resin.

In the pressure-holding step, when the pressure pin 355 is moved forward, the pressure block 68 moves to the side wall portion 215b side and the resin in the discarding boss portion 215c is removed from the side wall portion 215b.
Push into. Then, when the pressure pin 355 is moved forward, the pressure surface of the pressure block 68 and the side wall portion 2
By setting the surfaces of 15b so that they are flush with each other, it is possible to prevent the rib portion from being formed in the molded product.

In this case, since the discarding boss portion 215c is formed by the pressure block 68, the pressure pin 355 is formed.
It is not necessary to expose the tip of the tongue portion 215a. In addition,
The present invention is not limited to the above-described embodiments, but various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0048]

As described in detail above, according to the present invention, in the local pressure injection molding method, resin is filled in the cavity and the discarding boss with the pressure pin retracted, and the pressure is applied. The pin is advanced to push the resin in the waste boss portion directly into the rising portion of the cavity.

Therefore, even if the top portion of the cavity is thin, the resin in the waste boss portion can be sufficiently pushed into the rising portion. As a result, sink marks and warpage are not generated in the side wall portions of the molded product, and inward warpage is not generated in the side wall corner portions. In the local pressure type injection molding machine of the present invention, a fixed mold and a movable mold which is disposed so as to come in contact with and separate from the fixed mold and forms a cavity therebetween.
A pressure pin that extends through the movable mold, faces the rising portion of the cavity and faces the top of the cavity, and forms a discarding boss portion forward, and the pressure pin advances. Drive means.

Therefore, by advancing the pressure pin, the resin in the waste boss portion can be sufficiently pushed into the fillet portion and the rising portion. As a result, sink marks and warpage are not generated in the side wall portions of the molded product, and inward warpage is not generated in the side wall corner portions. In another local pressure type injection molding machine of the present invention, a fixed mold, a movable mold which is disposed so as to be contactable with and separable from the fixed mold, and forms a cavity between the fixed mold, and the movable mold in the movable mold. And a pressure pin arranged so as to be movable back and forth. A pressurizing block is disposed so that the pressurizing surface faces the rising portion of the cavity, and the pressurizing block is moved as the pressurizing pin moves back and forth.

Therefore, by advancing the pressure pin, the pressure block moves, and the resin in the waste boss can be sufficiently pushed into the fillet portion and the rising portion. As a result, sink marks and warpage are not generated in the side wall portions of the molded product, and inward warpage is not generated in the side wall corner portions. Further, when the pressure pin is moved forward, by setting the pressure surface of the pressure block and the surface of the side wall portion so as to be aligned with each other, it is possible to prevent the rib portion from being formed on the molded product. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a state inside a cavity according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a conventional local pressure injection molding machine.

FIG. 3 is a diagram showing a state inside a cavity when a box-shaped molded product is molded by a conventional local pressure injection molding machine.

FIG. 4 is a view showing a molding state of a conventional box-shaped molded product.

FIG. 5 is a sectional view of a local pressure type injection molding machine to which the first embodiment of the present invention is applied.

FIG. 6 is a sectional view of a local pressure type injection molding machine to which a second embodiment of the present invention is applied.

FIG. 7 is a diagram showing a state inside a cavity according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a state inside a cavity according to a fourth embodiment of the present invention.

[Explanation of symbols]

 12 Fixed mold 14 Movable mold 36, 37, 363, 373 Pressure plate 68 Pressure block 212, 214, 215 Cavity 212a, 214a, 215a Fillet part 212b, 214b, 215b Side wall part 212c, 214c, 215c Discard boss Part 212d, 214d, 215d Side wall corner part 352, 354, 355 Pressure pin

Claims (3)

[Claims] 1. (a) The cavity and the discard boss are filled with resin with the pressure pin retracted, and (b) the pressure pin is advanced so that the resin in the discard boss directly rises in the cavity. A local pressure injection molding method characterized by being pushed into the part. 2. (a) a fixed mold, (b) a movable mold which is disposed so as to come in contact with and separate from the fixed mold and forms a cavity between the two, and (c) penetrates the movable mold. A pressing pin that extends toward the side of the rising portion of the cavity and the tip of the top portion of the cavity, and forms a discarding boss portion in the front.
A local pressurization type injection molding machine, comprising: a drive means for moving the pressurizing pin forward. 3. (a) a fixed mold; (b) a movable mold which is disposed so as to come into contact with and separate from the fixed mold and forms a cavity therebetween; and (c) in the movable mold. A pressurizing pin that is arranged to move back and forth; and (d) a pressurizing block that is arranged so that the pressurizing surface faces the rising portion of the cavity and that moves as the pressurizing pin moves back and forth. The featured local pressure injection molding machine.