JPH0383614A - Mold device for molding insert - Google Patents

Abstract

PURPOSE:To smoothly perform relase of a mold by forming the corner part of an inner circumference correspondent to the sharp edge part of an insert piece of a mold body into a recesslike escape part. CONSTITUTION:The corner part of an inner circumference correspondent to the sharp edge part 13b of the insert piece 13 of a mold body 10 is formed into a recesslike escape part 10a. Therefor the rate of thermal expansion allowed to act on the corner via a burr is absorbed into the escape part 10a. Resistance in release of a mold of the insert I for the mold body 10 is made small. As a result, trouble is not caused even when the burr is not previously removed and thereby release of the mold can be smoothly performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold device for insert molding [Prior Art] A mold device for insert molding is used, for example, in a kettle handle body made of a metal material. When applying a coating made of resin material to provide heat insulation function while utilizing the strength of the main body, or applying a coating made of resin material to the main body part made of metal material such as control equipment parts. It is used in cases where it has an insulating function. In addition, as shown in Figures 4 to 7,
It is also used when an insert L made of a metal material is added to a molded article A made of a resin material to give it a decorative function.

Taking as an example the case where this decorative function is provided, a conventional mold device for insert molding will be explained in detail. In this device, as shown in FIG. The molded product A is bottom-shaped in the space S formed between the protrusion 11 and the recess 1 of the lower mold 10.
An insert (2) is set in advance in the molded article (2), and the insert (I) is attached to the molded article (A) after molding and is removed from the mold. In this case, the recess 12 of the lower mold (mold) 10 has a square (polygonal) inner peripheral surface, and a plurality of ( 4) The insert pieces 13... are fitted. As shown in FIG. 5, each insert piece 13 is made of L-shaped channel material and is finished as an isosceles trapezoid with a low height when viewed from above, and has a shape on each side of the inner periphery. Both ends in the direction along the line are acute-angled portions 13b13 having 45-degree end surfaces 13a, 13a so as to be tapered.
b. These insert pieces 13...
The end surfaces 13a, 13a abut each other and are combined so that they are at right angles, thereby setting the frame-shaped insert 4 in the recess 12.

As shown in FIG. 4, the insert I is located at the lower end of the space S, and insert molding is performed in this state.

[Problem to be solved by the invention]

By the way, since the corners 12a of the recessed portion 12 have a right-angled shape when viewed from above, the acute-angled portions 1
If 3b has a "burr" during manufacturing, the burr will come to the corner 12a, and when the thermal expansion effect of molding works in that state, the burr will be strongly pressed against the corner 12a... Become. If the burr is strongly pressed against the corner 12a in this way, the resistance during demolding will increase and it will become difficult to demold, especially when the insert piece 13
If there was a height, the degree of resistance would be high and demolding would be extremely difficult. If you try to force this demolding, it will be done by a knockout pin, and according to this,
A large force was applied to molded product A, causing internal distortion and external damage, leading to quality deterioration, and lower mold 1
0 was also damaged. When demolding resistance was high, productivity decreased. To prevent this, the burrs may be removed before setting, but this poses the problem of high processing costs.

This invention was made in view of the above-mentioned circumstances, and its object is to enable smooth demolding, improve the quality of molded products, protect molds, and improve productivity at low cost. The purpose is to do so.

[Means to solve the problem]

In order to solve the above problems, the insert molding mold device according to the present invention is provided with a mold body having a recessed portion having a polygonal inner circumferential surface shape, and a recessed portion having an acute angle portion at both ends within the recessed portion. The insert pieces are fitted along each side of the inner periphery of the polygon so that adjacent insert pieces abut the end faces of the acute angle portions against each other to form an insert, and the insert pieces are inserted into the molded product after molding. In a mold device for insert molding which is adapted to be removed from the recessed portion, an inner peripheral corner portion of the mold body corresponding to an acute angle portion of the insert piece is a recessed relief portion. .

[For production]

If the inner peripheral corner portion of the mold body corresponding to the acute angle portion of the insert piece has a concave relief portion, the thermal expansion that acts on the corner through the burr is absorbed into the relief portion, and the insert piece Demolding resistance against the mold body is reduced. Since demolding resistance is reduced, it is no longer necessary to remove the burrs in advance.

〔Example〕

Hereinafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings.

1 to 3 show an embodiment of the insert molding mold device according to the present invention. This insert molding mold device is intended for those that add the decorative function explained in the previous example, and in these figures, the same members and parts as shown in Figures 4 to 7 are not shown. The same reference numerals are given to them, and redundant explanation will be omitted.

By the way, the inner circumferential corner portion of the lower die 10 is a concave relief portion 10a having a partial shape of a cylindrical surface, so as to partially absorb the thermal expansion through the insert piece 13. It has become. Note that the acute angle portion 13b of each insert piece 13 is 9. Although it is not finished to remove burrs, it may be done. The relief part 1
Although it is advantageous in terms of strength that Oa is round (such as a part of a cylinder), other shapes are possible.

As described above, in the insert molding mold device according to the present invention, the inner circumferential corner portion of the mold body corresponding to the acute angle portion of the insert piece is a recessed relief portion, so that the insert molding device can be inserted through the burr. Thermal expansion acting on the corner is absorbed into the relief portion, reducing the mold removal resistance of the insert against the mold body. Since demolding resistance is reduced, it is no longer necessary to remove the burrs in advance. the result,
The internal distortion and external damage caused to the molded product by demolding are suppressed, and a molded product with good internal and external appearance can be obtained, and damage to the mold body is also reduced. Since demolding resistance is reduced, the molded product can be quickly demolded and productivity can be improved. As mentioned above, since there is no need to separately remove the burrs, there is no need to increase costs.

Note that the recessed portion may have another polygonal shape. The means for demolding was by a knockout bottle,
Since demolding resistance is reduced, for example, when a molded product with a low height is to be targeted, demolding may be performed using air pressure. In this case, internal distortion and external damage to the molded product can be further suppressed.

〔Effect of the invention〕

Since the insert molding mold device according to the present invention is configured as described above, demolding can be performed smoothly, and the quality of the molded product, protection of the mold body, and productivity can be improved at a low rate. It will be possible to reduce costs.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a lower die of an embodiment of the insert molding mold device according to the present invention, Fig. 2 is an enlarged plan view of the main parts thereof, and Fig. 3 is a cross-sectional view taken along the line mm in Fig. 2. , FIG. 4 is a cross-sectional view of a conventional mold device for insert molding, FIG. 5 is a perspective view of an insert piece, and FIG. 6 is a perspective view of a state in which the insert piece is added to a molded product. FIG. 7 is a perspective view showing the insert piece fitted into the lower die in FIG. 4.

Claims (1)

[Claims] 1. A recess with a polygonal inner circumferential surface is provided in the mold, and insert pieces with acute angles at both ends are inserted into the recess along each side of the inner circumference of the polygon and adjacent to each other. The insert is constructed by fitting the insert pieces so that the end faces of the acute angle portions abut each other, and the insert is attached to the molded product after molding and is removed from the recess. A mold device for insert molding, characterized in that an inner peripheral corner portion of the mold body corresponding to an acute angle portion of the insert piece is a recessed relief portion.