JPH0531763A - Injection molding die - Google Patents

Abstract

PURPOSE:To shorten the molding cycle of a molded product with a precision portion and improve the durability of a cavity. CONSTITUTION:For the purpose of injection molding a molded product with a precision portion of high accuracy, a molding block 4 from a part of a cavity 11 for molding the precision portion is formed by a high heat conductive material, and a channel 41 for molding the precision portion is formed at the end on the molding block 4 out of a hard material.

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 molding a molded article having a highly accurate precision portion by injection molding. For example, the precision portion is formed into a groove shape and is continuously connected to a discharge port. The present invention relates to an injection molding die that can be particularly preferably applied to form an ink flow path forming groove of a liquid jet recording head that performs recording with droplets from an ejection port.

[0002]

The applicant of the present application has proposed an ink jet recording apparatus in which a liquid jet recording head integrally formed with an ink container can be attached to and detached from the ink jet recording apparatus to improve operability and maintainability. There is. As shown in FIGS. 9 and 10, this ink jet recording head is formed as a top plate component 400 as an integrally molded product, and has a recess 430 for forming a common liquid chamber for ink and an ink flow path communicating with the recess 430. A large number of forming groove portions 411 and 412 (only two of which are shown by broken lines in the figure) and the orifice plate portion 404 are integrally provided. Ink ejection holes 421 and 422 are formed in the orifice plate portion 404 by using a laser drilling device or the like. As described above, the top plate component 400 and the orifice plate portion 404 are simultaneously formed integrally with each other in the mold, while the groove portion 41 of the ink flow path is formed.
For 1 and 412, etc., a mold part formed by a method such as cutting is provided in the cavity with a fine groove having a shape opposite to the groove part,
A molded product of the top plate component 400 is obtained by performing resin injection.

As shown in FIG. 6, a heater substrate 100 having a discharge heater 105 and the like is applied to the orifice plate portion 404 of the top plate component 400 thus obtained, and then bonded to form a completed recording head. Trying to get. The size of each part of the recording head completed through the above steps is determined according to the printer specifications. For example, when the dot recording density is high, the groove widths of the groove portions 411, 412 and the like are set to 32 μm (microns). The width dimension of the non-groove portion is set to 31.5 μm. As a result, the groove 41
The width dimension of the convex portion of the molding die corresponding to the portion for molding 1, 412 is set to 31.5 μm. Here, when molding a molded product having a fine groove shape as described above, in order to make sure that the molten resin material reaches the fine groove portion and to fit into the mold portion, Conventionally, high mold temperature molding has been performed in which the resin is kept in a high temperature state and the fluidity of the resin material is increased to perform injection molding.

[0004]

However, when a mold part having fine groove-shaped parts is formed in a part of a cavity of a mold forming a main body part of a molded product having a precision portion such as the above-mentioned groove part. Is the portion where cooling of a precision portion such as a groove portion is most delayed due to restrictions on the structure of the cavity. In addition, since the precision portion is required to have a particularly precise shape, the formed product cannot be taken out until the portion is completely cured, resulting in a problem that the molding cycle becomes long.

On the other hand, if the molding piece forming the precision portion is made of a material having a high thermal conductivity such as phosphor bronze to shorten the superheat cooling cycle, the wear resistance of phosphor bronze is low and the precision portion mold is There is a problem that the part cannot be accurately maintained for a long period of time. Therefore, the present invention has been made in view of the above problems, and an object thereof is to shorten the molding cycle of a molded product having a precision portion. Further, in addition to the above object, it is to improve the durability of a cavity for molding a molded product having a precision portion.

[0006]

In order to solve the above-mentioned problems and to achieve the object, an injection mold of the present invention is an injection mold for injection-molding a molded article having a high precision part. In, a molding piece forming a part of the cavity for molding the precision portion is formed of a high thermal conductive material, and a mold portion for molding the precision portion is made of a hard material on the molding piece portion. The structure is formed by. Further, preferably, the precision portion has a plurality of fine groove shapes.
Further, preferably, the high thermal conductivity material is phosphor bronze, and the hard material is formed by electrolytic chemical nickel plating and then machined to form the mold part.

[0007]

With the above structure, when the molten resin is injected into the cavity to injection-mold a molded article having a high precision precision portion, the molding die portion of the precision portion is formed of a high thermal conductive material. The mold piece is cooled, while the mold part made of hard material serves to minimize wear. Further, the precision portion has a plurality of fine groove shapes,
Use molded parts for ink recording head components. Further, the molding piece is made of phosphor bronze, which is a highly heat-conductive material, and the hard material of the mold part is formed on the molding piece by electrolytic chemical nickel plating and then machined to improve the accuracy of the mold part.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention, which is a preferred embodiment of the present invention, will be described with reference to the drawings with respect to a constitutional example of an injection molding die in which a precision portion is formed as an ink flow path. FIG. 1 is a cutaway view showing the injection molding die of the first embodiment broken into four parts. The center spool 103 is formed in a runner 12 separated in four directions because of the multi-cavity die construction. The state of the cavity 11 that is provided so as to be continuous and communicates with one of the runners 12 therein is shown.

FIG. 2 is a detailed sectional view of the main part around the cavity 11 of FIG. First, in FIG. 1, a mold 100 shown by a chain double-dashed line in the drawing has a well-known multi-cavity mold structure in which slide pieces 2 are radially arranged, and a molten resin is introduced into a cavity 11 via a spool 103. Inject
After the resin is cured, the mold is opened from the separation surface PL and the molded product is taken out.

For this purpose, a fixed piece 1 forming a part above the cavity 11, a slide piece 2 for mold clamping, an ejector pin 3 forming a part of the cavity 11 at its end, and a precision portion. A groove piece 4 in which a mold portion for forming is formed as described later, a nesting pin 5 which sneaks into the cavity 11 to mold a space portion of a molded product, and a cavity 11.
The movable piece 6 forming a part of the lower part of the runner and a part of the lower part of the runner 12 is arranged as shown.

Next, in FIG. 2, the tip portion 5a of the nesting pin 5 sneaks into the cavity 11 communicating with the runner 12 through the film gate G. Further, below the film gate G and the runner 12, an ejector pin 13 that is guided by the movable piece 6 and acts to take out the runner 12 is provided. On the other hand, the groove portion 41, which is the mold portion of the precision portion of the cavity 11, is configured on the side surface portion of the groove piece 4 as described below, and forms a part of the cavity 11. Further, near the left side of the groove 41 in the figure, a narrow portion 11b of the cavity 11 is provided, which is continuous with the lower plate portion 11a. The lower end portion of the plate portion 11a is formed so that the width thereof becomes gradually narrower as shown in the drawing, and the protruding portion 3 of the ejector pin 3
The plate portion 11a of the cavity 11 is configured so as to be closed by the upper end portion 3h of a.

Here, the ejector pin 3 is provided with a hole portion 31 shown by a broken line in the drawing, and cooling air is sent into the hole portion 31 to cool the ejector pin 3 and the groove piece 4. Thus, the hardening of the molten resin in the cavity 11 can be promoted. Next, FIG. 3 is an external perspective view of the groove piece 4 of FIG. 2, in which the peak dimension is 31.5 μm (micron) and the valley width dimension is set to 32 μm on the upper surface of the groove piece 4. While a large number of grooves 41 are formed, and shoulder notches 4a and 4b are formed on both sides thereof as shown in the drawing, the molten resin flows in the direction of arrow X.

These shoulder notches 4a and 4b form a flow path for the resin to sufficiently flow into the plate portion 11 of the cavity 11 described above. Next, FIG. 4 is a sectional view of the groove piece 4. The groove piece 4 is composed of a base material portion 4c having good thermal conductivity and a hard layer 4d formed on the surface and having a substantially uniform thickness. ing. Various materials can be selected for the base material portion 4c having good thermal conductivity. However, phosphor bronze is used and a nickel plating layer 4d is formed on the surface thereof by electrolytic chemical plating, and then a special cutting device is used. Good results were obtained by machining the grooves 41 at equal intervals.

By configuring the groove piece 4 as described above, the thermal conductivity is improved and the hardening of the resin can be accelerated, while the wear resistance of the groove portion 41 is improved. Also,
FIG. 5 is a partial external perspective view of the ejector pin 3.
As shown in the figure, the ejector pin 3 is used to protrude from the cavity 11 at the time of mold opening of the plate portion molded in the second narrow portion 11a of the cavity 11, and thus is formed in a flat rectangular shape as shown in the figure. .

The ejector pin 3 having the above structure
The protrusion 3a, the thick portion 3b, and the hole 31 through which cooling air is passed are formed in the central portion.
The operation of the mold structure described above will be described with reference to the flow chart of FIG. 6. After the start of molding, the mold closing residual heat is performed in step S1. When the sensor 101 (FIG. 1) detects that the residual heat temperature has risen to a predetermined temperature, the process proceeds to step S2, and when the molten resin is injected from the nozzle (not shown) to the spool 103, the molten resin passes through the runner 12 and the gate G. To fill the cavities 11 and 11a. At this time, the narrow portion 11b between the cavity 11 and the plate portion 11a is narrowed due to the restriction of the shape of the molded product, which impedes the flow of the molten resin.
After passing through the shoulders 4a and 4b as the flow path, the plate portion 11a of the cavity 11 is immediately filled. Further, since the mold temperature is kept high, the groove 41 having the fine groove shape or the narrow portion 11b forming the thin plate portion can be effectively filled in the molten state.

This is the end of step S3, and step S
4, a predetermined cooling time is waited for the resin to harden in the cavity 11, but before and after this, air is blown from the hole 31 of the ejector pin 3 to the ejector pin 3 and the groove piece 4 in step S5. By injecting into the gap portion formed between them to cool the groove piece 4, the groove portion 41
It accelerates the cooling and hardening of the precision parts formed by. After that, the process proceeds to step S6, where the mold is opened from the mold release surface PL and the like, and at step S7, the molded product is ejected by an ejector pin or the like. Finally, in step S8, the molded product is taken out, one molding cycle is completed, and the next molding cycle is started. As described above, in step S5, the air is forcibly injected into the gap formed between the ejector pin 3 and the groove piece 4 to cool the groove piece 4, thereby shortening the time required to eject the formed product. can do. Further, since the base material 4c of the groove piece 4 is made of a material having high thermal conductivity, cooling is performed more quickly.

Further, since the groove portion 41 of the groove piece 4 is formed by machining the hard layer 4d after forming the hard layer 4d by nickel plating or the like, it has nothing to do with the nickel plating thickness. The groove shape can be formed with higher accuracy than in the case of forming by plating or the like. Next, FIG. 7 is a detailed cross-sectional view of the main part around the cavity 11 of the second embodiment, and since it is constructed in substantially the same manner as the above-mentioned mold, the same components will be assigned the same reference numerals and described. To omit the description, the difference will be described. The ejector pin 3 is positionally regulated by the movable side pressing piece 7, while the elongated hole 32 opened in the hole 7a formed in the movable side pressing piece 7. ing. As shown in the perspective view of FIG. 8, the elongated hole portion 32 is formed so that the width of the ejector pin 3 is gradually reduced.
Since it is formed to face the upper end 3h of the protruding portion 3a, the upper end 3h to the groove 41 due to the cooling air flow.
Can be cooled more efficiently.

As described above, the molding piece forming the precision portion of the molded product and the cavity body are separately configured,
Furthermore, the molding piece that forms the fine grooves is made of a material with high thermal conductivity, and a hard layer is formed on the surface of the molding piece to form a mold part, so that the precision part can be cooled quickly, and the molding cycle can be shortened. Since the groove-shaped portion can be formed of a material having high hardness, durability can be improved. In each of the above-described embodiments, the description has been limited to the molding example of the ink recording head component, but needless to say, the present invention is not limited to this. It can also be applied to molded products.

[0019]

As described above, according to the present invention, the molding cycle of a molded product having a precision portion can be shortened. In addition, the durability of the cavity for molding a molded product having a precision portion can be improved.

[Brief description of drawings]

FIG. 1 is a cutaway view of a first embodiment of an injection molding die cut into four parts.

FIG. 2 is a fragmentary sectional view around a cavity 11 of FIG.

FIG. 3 is an external perspective view of a groove piece 4.

FIG. 4 is a cross-sectional view showing a configuration of a groove piece.

FIG. 5 is an external perspective view of an ejector pin.

FIG. 6 is an operation flow chart.

FIG. 7 is a detailed cross-sectional view of a main part around a cavity 11 according to a second embodiment.

FIG. 8 is an external perspective view of an ejector pin.

FIG. 9 is a model diagram showing the shape of a molded product.

FIG. 10 is a model diagram showing a completed state of a molded product.

[Explanation of symbols]

1 fixed piece, 2 slide pieces, 3 ejector pins, 4 groove pieces, 5 Nesting pins, 6 movable pieces, 7 movable side pressing piece, 11 cavities, 31 holes, 32 holes, 41 It is a groove.

Claims (3)

[Claims] 1. An injection molding die for injection-molding a molded article having a high precision part, wherein a molding piece forming a part of the cavity for molding the precision part is made of a high heat conductive material. And a mold for molding the precision part is formed of a hard material on the molding piece. 2. The injection molding die according to claim 1, wherein the precision portion has a plurality of fine groove shapes. 3. The high thermal conductive material is phosphor bronze, and the hard material is formed by electrolytic chemical nickel plating and then machined to form the mold part.
Alternatively, the mold for injection molding according to claim 2.