JPH1199540A - Injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent facial precision of a molded product from being deteriorated when the injection molded product is ejected out with a nest by a method wherein an escape part likely to prevent an edge part of a mirror face part of a movable nest from coming in contact with a hole bored in a movable side template, is provided. SOLUTION: Upper and lower ejector plates 23, 24 are ejected with an injection molding machine ejector rod. At that time a movable nest 18 and an ejector pin 22 are also ejected out in the same way via the ejector rod 21, and a molded product is released from a movable side mold 4. Though the movable nest 18 is slid in a hole 16 in that case, a clearance is formed so that an edge part 21 of a mirror face part 20 of the movable nest 18 does not come in contact with an escape part 25. Therefore, the molded product comes to be ejected from a recessed part 14 of a movable side template 10 without shoulder touch of the edge part 21 of the mirror face part 20 onto the hole 16. Then, by a comparatively simple structure, deterioration of facial precision of the molded product generated by ejecting the movable nest 18 from the hole 16 of the movable side template 10 fitted, in a freely slidable manner, can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold for projecting a molded article to be injection-molded by nesting.

[0002]

2. Description of the Related Art In order to take out a plastic optical component such as an injection-molded lens or prism from a mold for injection molding as a molded product, a method of projecting the molded product from a movable mold plate having a cavity is common. It has been done.

[0003] Japanese Patent Application Laid-Open No. 6-143363 discloses an injection molding die utilizing such a technique. The injection molding mold described in the above-mentioned publication is one in which a molded product is a lens of a plastic optical component, and a cavity is formed on a parting line surface sandwiched between a fixed mold plate and a movable mold plate. ing. On the movable mold plate side, a hole formed in the bottom surface of the recess with a concave shape corresponding to the outer shape of the lens with respect to the movable mold plate (the direction of the hole is perpendicular to the parting line surface). Is formed, and an insert having a mirror surface portion to be transferred as an optical lens surface in the hole is slidably fitted and arranged, so that a part of the cavity is formed by the inner surface of the concave portion and the mirror surface portion of the insert. Form. To remove the lens after the injection molding, the mold is opened between the fixed mold plate and the movable mold plate, and then the nest is moved to the concave side with respect to the movable mold plate, whereby the lens is moved to the movable mold plate. This is done by projecting from a recess in the plate.

[0004]

However, in an injection molding die attached to a horizontal injection molding machine,
The insert will slide horizontally. Therefore, the edge of the nest on the mirror surface side comes into contact with the hole of the movable mold plate slidably fitted thereto, and in this state, the lens is removed from the concave portion of the movable mold plate. When it protrudes, there is a problem that the surface accuracy of the lens is deteriorated. This phenomenon is a phenomenon in which the outer shape of the molded product is more common in a square lens than in a circular lens.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and when an injection-molded molded product is protruded by nesting, an injection-molding metal which does not deteriorate the surface accuracy of the molded product. The purpose is to provide a type.

[0006]

According to a first aspect of the present invention, there is provided an injection molding die, in which a molded product to be injection molded is slidably fitted into a hole formed in a movable mold plate. In an injection molding die protruding with a child, the movable insert is inserted into one of a movable insert having a mirror surface portion to be transferred to the molded product or a hole of a movable mold plate into which the movable insert is fitted. The mold for injection molding according to claim 2 of the present invention is characterized in that it has a relief portion such that the edge of the mirror surface portion does not contact the hole formed in the movable side mold plate. When the inner peripheral surface of the hole of the movable mold plate corresponding to the edge of the mirror surface portion of the movable insert is 0.02 mm smaller than the inner peripheral surface of the movable insert that is not the edge.
It is characterized in that it is an embossed portion having a size of not more than mm. The relief portion preferably has a thickness of 0.003 mm to 0.02 mm.

According to a third aspect of the present invention, there is provided the injection mold according to the first aspect of the present invention, wherein the embossed portion of the first aspect is formed by removing an outer peripheral surface of an edge of a movable insert having a mirror surface portion to be transferred to the molded product. It is characterized in that it is an embossed portion which is smaller than the outer peripheral surface of the movable insert by 0.02 mm or less. This part is
0.003 mm to 0.02 mm is preferred.

According to the injection molding die of the first, second and third aspects, the resin is injected into the die, and after the resin is cooled and solidified, the die is opened to project the movable insert, When the molded product is released from the mold, the edge of the mirror surface portion of the movable insert does not hit against the hole of the movable mold plate due to the relief portion, which impairs the surface accuracy of the molded product. Without mold release.

According to the third aspect of the present invention, an embossed portion can be formed very easily.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment of the Invention) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view in which a part of the injection mold is sectioned, FIG. 2 is an enlarged view in which a main part of FIG. 1 is enlarged, and a plan view for explaining a case where the part is viewed from above.

In FIG. 1, an injection mold (hereinafter, referred to as a mold) 1 attached to an injection molding machine has a fixed mold 3 with a parting line surface (PL surface) 2 as a separation surface.
And the movable mold 4. The fixed mold 3 is formed by integrally connecting the fixed mounting plate 5 and the fixed mold plate 6 to each other.
The movable mold 4 is formed by integrally connecting a movable mounting plate 7, a spacer block 8, a movable receiving plate 9, and a movable mold plate 10.

The fixed-side mold plate 6 and the movable-side mold plate 10 have cavities 12 for forming molded products at corresponding positions on the PL surface 2 side. The cavity 12 for molding the molded product has concave portions 13 formed corresponding to the outer shape of the lens (the outer shape of the flange portion) at the corresponding positions of the fixed mold plate 6 and the movable mold plate 10, respectively. 14 and the recess 1
Holes 15, 16 drilled in bottom surfaces 13a, 14a of 3, 14
And nests 17 and 18 arranged inside. The insert 17 disposed on the bottom surface 13 a of the concave portion 13 of the fixed template 6 is a fixed insert 17 fixed to the fixed template 6.
The end surface on the concave side is a mirror surface portion 19 for transferring the optical lens surface to a molded product.

An insert 18 disposed on the bottom surface 14a of the concave portion 14 of the movable mold plate 10 has a long circular hole 16 having the same diameter and long penetrating through the movable mold plate 10 and the movable receiving plate 9. Movable cylindrical insert 1 that slidably engages
8 and the end surface on the concave side is a mirror surface portion 20 for transferring the optical lens surface to the molded product.

The base end side of the movable insert 18 is connected to a protruding rod 21 by a bolt 22, and the base end side of the protruding rod 21 is connected to an ejector plate 23 and an ejector rod 23 similarly to the eject pin 22. It is sandwiched by the lower plate 24. The fixed side template 6
The resin passage 25 to the cavity 12 formed at the position corresponding to the movable mold plate 10 is carved into the sprue bush 26, the fixed mold plate 6, and the movable mold plate 10 arranged on the fixed mold 3. It is formed by grooves such as sprues, runners and gates.

A recess 14 formed in the movable mold plate 10
And the movable insert 18 disposed in a hole 16 formed in the bottom surface 14a of the concave portion 14, and the concave portion 14 and the movable insert 1
FIG. 2 is an enlarged view for explaining a mutual relationship before injection molding of No. 8.

In FIG. 2, the mirror surface portion 20 of the movable insert 18 is shown.
The edge 21 of the recess 14 and the bottom surface 14a of the recess 14 are at the same height (on the same surface), and the upper surface of the elongated hole 16 for guiding the movable insert 18 slidably (that is, In the range of 3 mm from the bottom surface), a relief 25 having an inner diameter 0.01 mm larger than the inner diameter of the hole fitted with the movable insert 18 is formed.

Since the length of the movable insert 18 is as long as 25 mm, even if the movable insert 18 is inclined in the hole 16, the edge 21 of the mirror surface portion 20 is set so as not to contact the relief portion 25. I have. The clearance between the inner peripheral surface of the elongated hole 16 that guides the movable insert 18 slidably and the outer peripheral surface of the movable insert 18 is 0.01 mm or less.

Accordingly, the gap between the outer peripheral surface of the movable insert 18 and the inner peripheral surface of the ridge 25 is smaller than 0.03 mm,
The dimensions are set so that even when the resin is injected into the cavity at the time of molding, the resin does not flow around the relief portion.

That is, the inner peripheral surface of the hole of the relief 25 is larger than the inner peripheral surface of the hole 16 of the movable insert 18 not corresponding to the edge 21 by 0.02 mm or less. In the case of the relief portion in the range of 0.003 mm to 0.02 mm, since the resin does not flow around the relief portion, the dimension is set in the above range.

When the injection molding die having the above configuration is mounted on a horizontal injection molding machine for molding, first, FIG.
In this state, the resin is injected into the sprue bush 26 from an injection molding nozzle (not shown).

The injected resin is filled into the cavity 13 through the resin flow path 25, and is cooled after the filling is completed. After the resin is cured in the cooling step, the mold is opened from the parting line surface 2 and the upper and lower ejector plates 23 and 24 are projected by an injection molding machine projecting lot (not shown).

At this time, the movable insert 18 and the eject pin 22 are similarly projected via the protruding rod 21, and the molded product is released from the movable mold 4. At this time, even if the movable insert 18 slides in the hole 16, a relief (a gap) is formed so that the edge 21 of the mirror surface portion 20 of the movable insert 18 does not contact the relief 25. The molded product protrudes from the concave portion 14 of the movable mold plate 4 without the edge 21 of the mirror surface portion 20 coming into contact with the hole 16.

According to the injection molding die of the present embodiment, a molded product produced by projecting the movable insert from the hole of the movable mold plate slidably fitted with a relatively simple structure. Surface accuracy can be prevented from deteriorating.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a front view of a fitting part of a movable insert and a movable mold plate, in which main parts of an injection molding die are enlarged, and a plan view for explaining a case where this part is viewed from above.

The injection molding die according to the second embodiment differs from the first embodiment only in the configuration of the relief portion formed between the movable insert and the movable mold plate. I do. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

That is, in the injection molding die of the first embodiment, the outer periphery of the movable insert 18 has the same diameter (straight shape) as a cylindrical shape, and the relief portion 25 is formed on the movable mold plate 10. However, in the injection mold according to the second embodiment, as shown in FIG. 3, an embossed portion 31 is formed on a movable nest 30 having a rectangular cross section and a hole in a movable side mold plate 32. Is straight.

More specifically, the movable insert 30 having a rectangular cross section with a rectangular cross section is formed with a relief portion 31 whose entire circumference is smaller than the outer shape by 0.005 mm at a height of 3 mm from the mirror surface portion 33. On the other hand, a long hole 34 having a rectangular cross section which is slidably fitted to the movable insert 30 in the movable mold plate 32.
Are formed in the movable mold plate 32 in the same size.

As described above, the outer peripheral surface of the edge of the mirror surface portion of the movable nest is 0.02 mm larger than the outer peripheral surface of the movable nest that is not the edge.
The nick portion 31 reduced in the following dimensions, preferably 0.0
In the relief portion formed in the range of 03 mm to 0.02 mm,
Since the gap between the inner peripheral surface of the hole 34 and the outer peripheral surface of the relief portion 31 is 0.03 mm or less, the dimensions are set so that the resin does not flow around.

In the first embodiment, the injection molding die having the above structure is mounted on a horizontal injection molding machine to perform molding.
Similarly to the above, even when the movable insert 30 slides in the hole 34 at the time of release of the molded product, the edge 35 of the mirror surface portion 33 of the movable insert 30 comes into contact with the hole 34 by the relief portion 31. Instead, the molded product can be projected from the concave portion 14 of the movable mold plate 32.

According to the second embodiment, the following effects can be obtained. In the first embodiment, when processing is difficult due to the shape of the relief portion formed on the movable mold plate, for example, when the cross-sectional shape of the relief portion is rectangular, it is difficult to process the relief portion. As described above, the formation of the relief portion on the outer periphery of the movable insert can be extremely easily performed, so that the injection mold having the relief portion can be easily manufactured.

[0031]

According to the injection molding dies of the first, second and third aspects, the edge of the mirror surface portion of the movable insert does not hit against the hole of the movable mold plate. It is possible to obtain an injection mold that does not degrade the surface accuracy of a molded product.

In particular, according to the injection mold of claim 3,
It is possible to easily manufacture an injection molding die without deteriorating surface accuracy.

[Brief description of the drawings]

FIG. 1 is a front view of a part of an injection molding die according to Embodiment 1 in a cross section.

FIG. 2 is an enlarged view of a main part of FIG. 1 and a plan view thereof.

FIG. 3 is an enlarged view of a main part according to a second embodiment and a plan view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Movable mold plate 12 Cavity 14 Depression 14a Bottom surface 16 Hole 18 Movable insert 20 Mirror surface portion 21 Protruding rod 25 Resin flow path 30 Movable insert 31 Recess 32 Movable mold plate 33 Mirror surface portion 34 Hole 35 Edge

Claims (3)

[Claims] 1. A molded product to be injection-molded is transferred to said molded product in an injection mold that protrudes with an insert that is slidably fitted into a hole formed in a movable mold plate. One of a movable insert having a mirror surface portion to be inserted and a hole of the movable mold plate into which the movable insert is fitted, and an edge of the mirror surface portion of the movable insert and a hole formed in the movable mold plate. Characterized in that the mold has an embossed portion that does not come into contact with the mold. 2. The relief portion has an inner peripheral surface of a hole of a movable mold plate corresponding to an edge of a mirror surface portion of the movable insert.
2. The injection molding die according to claim 1, wherein the die is an embossed portion having the following dimensions. 3. The relief portion according to claim 1, wherein the relief portion is a relief portion in which an outer peripheral surface of an edge of a movable insert having a mirror surface portion to be transferred to the molded product is reduced to a size of 0.02 mm or less. 2. The injection mold according to 1.