JPH0671698A - Injection mold - Google Patents

Abstract

PURPOSE:To uniformly pressurize an entire product and to easily form a resin product of a high accuracy by a general-purpose injection molding machine by providing means for deciding an amount of heated resin to be supplied in a stationary mold and a movable mold in an injection molding using the molds. CONSTITUTION:A screw reaches an advancing limit point in an injection cylinder, it is confirmed by a position sensor, pressure of a mold clamping ram is switched to a high pressure, a movable die plate is moved rightward, and a gate D between a recess 9 and a protrusion 17 is closed while pressing a buffer 22. When the gate D is closed, heated resin in the recess 9 is urged out, and fed outside from the recess 9 as indicated by an arrow. Further, when the movable die plate is pressed so that the gate D becomes zero, flow of the resin is stopped, and the resin remains in the recess 9 separate from the resin. The resin in the recess 9 becomes a quantity to meet a product to be accurately metered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for manufacturing precision parts by injection molding.

[0002]

2. Description of the Related Art Injection molding is a split mold in which a synthetic resin (thermoplastic plastic) heated and melted in an injection cylinder is pressed (injected) at high speed into a mold closed tightly by a screw or a plunger to be cooled and solidified. The product is taken out by releasing. The product taken out in this way may have a difference in mold pressure due to a difference in distance from the injection position, a difference in post-shrinkage due to an imbalance in wall thickness, or a difference in flow viscosity due to a variation in melting resin temperature. Distortion due to warpage, deformation, etc. and dimensional variation are generated. Since these problems are not a problem in some fields of synthetic resins, they are flowing as products as they are, but in industrial parts etc., they are required to be improved as a major problem, and as a result, injection molding machines have been used for many years. Improvement of the control function of, low pressure molding method, high pressure injection molding method, injection compression molding method, gas pressure molding method and so on are being developed.

[0003]

However, even if the development is carried out in this way, a stable pressure is applied to prevent volumetric shrinkage when a fixed amount of the heat-melting resin is supplied to the product portion in the mold to solidify. However, the more complicated it is, the more complicated the equipment becomes and the more expensive the equipment becomes, which is very inconvenient in processing or manufacturing.

[0004]

The present invention solves such inconvenience, and the amount of the molten resin to be supplied to the product portion is determined by the product portion, and occurs when the fixed amount of the resin solidifies by cooling. An object of the present invention is to provide an injection molding die capable of manufacturing a highly accurate product by compressing the volume by moving the die to compress the volume and uniformly applying pressure to the product portion.

That is, in injection molding using a mold,
A concave mold consisting of an injection hole and a concave part of an arbitrary shape that shaped the product, and sliding holes at appropriate positions on both sides of the concave mold are drilled in the fixed mold plate, a guide hole is provided at the bottom of the concave part, and a sleeve is used as a buffer for the sliding hole. The fixed mold, which is inserted through the product, and the convex mold, which consists of convex parts of any shape obtained by molding the product, are projected on the movable mold plate corresponding to the concave mold, and the guide rod is guided to the appropriate position of the convex mold. A movable mold that is inserted so that it can be inserted into a hole is combined so that a fixed gap is maintained and the gap is connected to a concave mold. By moving the movable mold, the gate part between the concave mold and the convex mold is opened and closed. The convex shape fits in an appropriate amount. Furthermore, a product extrusion pin protruding in a convex shape on the movable mold plate is also provided in the movable mold, and a runner extrusion pin is fixed to the post-extrusion plate so as to be slidable corresponding to the injection hole, and is internally provided in the mold clamping ram. The plate after extrusion can be connected to the extrusion pin.

[0006]

[Function] Although the molten resin flows from the injection cylinder into the concave mold through the gap to fill it, the pressure in the mold clamping ram is so low that the gap is kept in a uniform condition and the amount of inflow is reduced. There is no need to weigh. Then, when the screw reaches the forward limit point, it is confirmed by the position sensor that the pressure of the mold clamping ram is switched to high pressure and the buffer is pushed to move the movable mold and the gate is closed. When the gate portion is closed, the heating resin in the concave mold flows out from the inside of the concave mold, and when the convex mold fits in the concave mold, the flowing out is stopped and the heating resin in the gap is cut off and remains in the concave mold. The amount of the heating resin remaining in the concave mold is the amount commensurate with the product, which means that the resin is accurately measured.

When the outflow stops, the solidification progresses and the volume shrinks, so that the convex mold is more uniformly pressed in the concave mold to cool and solidify. After the completion of cooling and solidification, the movable mold is moved to the left to release the convex mold from the concave mold, and the extrusion pin is operated to push the post-extrusion plate, push the runner push pin and the product push pin, push the product and the runner, and drop them. In this way, in the step of injection molding without weighing the heated resin, the concave and convex molds are automatically weighed, and the concave mold is used to manufacture precise products that adhere to the concave mold by uniform pressure. Can be done.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the figure, A indicates the whole fixed mold, 1 is a fixed mold mounting plate, and a sprue bush 2 is provided at the center and a mounting hole 3 for inserting
Has been drilled. 2 is a cylinder, and an injection hole 4 for supplying molten resin
In the sprue bush, a flange 5 is annularly provided at one end and a recess 6 is provided at the center of the end face. Reference numeral 7 denotes a fixed mold plate having the same shape as that of the fixed mold mounting plate 1, which has an insertion hole 8 for inserting the sprue bush 2 in the center thereof, and has a concave mold 9 formed of a concave part having an arbitrary shape for shaping the product. A guide hole 10 is provided in the center of the bottom of the concave mold 9 at a proper position to form a plurality of holes 1.
1 is provided, the sprue bush 2 is inserted into the insertion hole 8, and the fixed mold mounting plate 1 and the fixed mold plate 7 are fastened to each other at a plurality of locations by a fastener 12a made of a thread or the like. , A cylindrical sleeve 21 is slidably inserted into the slide hole 11 via the buffer body 22 of the coil spring, and the pressing plate 13 presses the flange 5 on the opposite side of the fixed mold plate 7 to press the sprue bush 2 It is prevented from falling off.

Reference numeral B denotes the movable mold as a whole, and 14 denotes a movable mold mounting plate having a pin hole 15 of an appropriate size in the center. Reference numeral 16 is a movable mold plate, and a convex mold 17 of a convex portion that fits into the concave mold 9 is provided on one side to correspond to the concave mold 9 and protrudes at an appropriate height. A rod-like shape that fits into the guide hole 10 has a rounded tip. The guide rod 18 provided with is provided so as to project in the center of the convex mold 17,
Plural extruding holes 19 are made to penetrate through the end face and extruding holes 20 are made corresponding to the injection holes 4, respectively, and a spacer block 23 is sandwiched between the movable die mounting plate 14 and the fastener 12b.
It is fixed at.

Reference numeral 24 is a push-out front plate that can be inserted between the spacer blocks 23, and push-out holes 19 and 2 of the movable mold plate 16.
The mounting holes 25 and 26 are bored corresponding to 0, the runner extruding pin 27 having an appropriate length is inserted into the mounting hole 26, the product extruding pin 28 is inserted into the mounting hole 25, and the extruding pins 25 and
Six heads are pressed and fixed, and the runner extruding pin 27 is inserted into the extruding hole 20 and the product extruding pin 28 is inserted into the extruding hole 19, so that the runner extruding pin 27 and the product extruding pin 28 can slide freely. Reference numeral 30 denotes a fixed die plate of the molding machine, which fixes the fixed mold mounting plate 1 and is provided with an injection cylinder 31 whose tip is in contact with the recess 6, and a screw 32 is movably provided in the injection cylinder 31. . Reference numeral 33 denotes a movable die plate provided at the tip of the mold clamping ram 34, which fixes the movable mold mounting plate 14 and pushes out the extrusion pin 3 in the mold clamping ram 34.
5 is inserted in the pin hole 15.

In use, the fixed die plate 30
The movable die for fixing the fixed die mounting plate 1 fixing the sprue bush 2 and the fixed die plate 7 to the movable die plate 33, and the movable die plate 16, the runner extrusion pin 27, and the product extrusion pin 28 on the movable die plate 33. After fixing the mold mounting plates 14 respectively and operating the mold clamping ram 34 to bring the concave mold 9 and the convex mold 17 into a mold clamped state, the screw 32 is moved to the left in FIG. From the injection hole 4 of the sprue bush 2 to the gap C between the fixed mold plate 7 and the movable mold plate 16.
And then flow into the concave mold 9 to be filled. In this state, since the pressure applied to the mold clamping ram 34 is in a low pressure state, the movable mold plate 16 is pushed through the sleeve 21 by the force of the buffer body 22 to maintain the equality, and the molten resin flowing in There is no need to adjust the amount.

When the screw 32 reaches the forward limit point, a position sensor (not shown in the figure) confirms it and the mold clamping ram 34
The pressure is switched to a high pressure, the movable die plate 33 moves to the right, and the gate portion D between the concave mold 9 and the convex mold 17 is closed while pushing the buffer 22 as shown in FIG. When the gate portion D is closed in this way, the heating resin contained in the concave mold 9 is pushed and flows out from the inside of the concave mold 9 to the outside as shown by the arrow. When the movable die plate 33 is pushed further, as shown in FIG.
When the gate portion D becomes zero as shown in (4), the heating resin stops flowing out and is cut off from the heating resin and remains in the concave mold 9.
The amount of the heating resin remaining in the concave mold 9 becomes an amount commensurate with the product, which means that it is accurately measured.

When the heated resin stops flowing out, solidification inevitably progresses and the volume contracts. Therefore, the movable die plate 33 moves further to the right, and the convex mold 17 is fitted into the concave mold 9 to uniformly pressurize it. It reaches the stopping point and stops as shown. After the completion of cooling and solidification, the movable die plate 33 moves to the left, the convex die 17 is separated from the convex die 9 from the concave die 9, and the extruding pin 35 operates to push the extruding plate 29 to push the runner extruding pin 27 and the product extruding pin. As shown in FIG. 5, a product extruding pin 28 drops the product in the concave mold 9 by pushing the runner extruding pin 28. After dropping the product, repeat this operation to process the products one after another. After that, the mold clamping ram 24 is returned to the original state, the runner extrusion pin 27 is returned to the original state, and the product extrusion pin 28 is returned to the next step to continue production.

[0014]

As described above, the present invention is higher than the prior art because the amount of heating resin required in the product portion can be directly measured in the mold and the entire product portion can be uniformly pressed. It is an excellent invention for industrial use because it has many features such as the ability to easily produce high-precision products with a general-purpose injection molding machine.

[Brief description of drawings]

FIG. 1 is a schematic view in which a part of an embodiment of the present invention is cut away.

FIG. 2 is an enlarged detailed view of a portion E in FIG.

FIG. 3 is an initial operation state diagram of the embodiment of the present invention.

FIG. 4 is an operation state diagram when the convex mold is fitted to the concave mold according to the embodiment of the present invention.

FIG. 5 is an operation state diagram when the convex mold is fitted to the concave mold of the embodiment of the present invention and the pressure solidification is completed.

FIG. 6 is an operation state diagram when taking out a product according to the embodiment of the present invention.

[Explanation of symbols]

 1 Fixed mold mounting plate 2 Spruge 3 Mounting hole 4 Injection hole 5 Flange 6 Recess 7 Fixed mold plate 8 Insertion hole 9 Recessed type 10 Guide hole 11 Sliding hole 12a Fastening part 13 Push plate 14 Movable mold mounting plate 15 Pin hole 16 Movable mold plate 17 Convex type 18 Guide rod 19 Extrusion hole 20 Extrusion hole 21 Sleeve 22 Buffer 23 Spacer block 24 Extrusion front plate 25 Mounting hole 26 Mounting hole 27 Runner extrusion pin 28 Product extrusion pin 29 Extrusion plate 30 Fixed die plate 31 Injection cylinder 32 Screw 33 Movable die plate 34 Mold clamping ram 35 Extrusion pin A Fixed mold B Movable mold C Gap D Gate

Claims (3)

[Claims] 1. An injection molding die having means for determining an amount of a heating resin supplied in a fixed die A and a movable die B in injection molding using a die. 2. The injection-molding die according to claim 1, further comprising means for press-molding with a compression margin obtained by determining a heating resin supply amount in the die. 3. In injection molding using a mold, a concave mold 9 comprising an injection hole 4 and a concave part, and sliding holes 11 formed at appropriate positions on both sides of the concave mold 9 in a fixed mold plate 7 and guided to the bottom of the concave part 9. Hole 1
0 is provided and the sleeve 21 is inserted into the slide hole 11 via the buffer 22, and the movable mold corresponding to the concave mold 9 and the convex mold 17 having the same shape as the concave mold 9 composed of the convex portion. A movable mold B, which is provided so as to project on the plate 16 and a guide rod 18 projects at an appropriate position of the convex mold 17 so as to be inserted into the guide hole 10, keeps a constant gap C and connects the gap C to the concave mold 9. The mold for injection molding according to claim 1, wherein the movable mold B is combined and the gate part D between the concave mold 9 and the convex mold 17 is opened / closed so that the convex mold 17 is fitted to the concave mold 9 in an appropriate amount. .