JPH0248909A - Mold release method of rubber molded product - Google Patents

Abstract

PURPOSE:To make removal of flashes unnecessary by leaving the flashes of product parts each behind within an intermediate mold, by a method wherein rubber product parts each of a rubber molded product are released by ejecting them simultaneously under a state where an annular rib of the intermediate mold where a rubber molded product is left behind and held is held not to separate from a relief groove. CONSTITUTION:When an intermediate mold where a rubber molded product is left behind and held is put on a lower press plate 20 and an ejection plate 12 is lowered, an upper press plate 16 abuts against the surface of the intermediate mold 1 and when the ejection plate 12 is lowered, the upper press plate 16 becomes a form where the intermediate mold 1 is held between the upper and lower press plates 16, 20 elastically with spring force of a compression coil spring 19. When the ejection plate 12 is lowered further, though product parts 21a each of a rubber molded product 21 is ejected with an ejection rod 13, since annular ribs 22, 23 are held down partly and incapably of separation, flashes of the products each are left behind on the intermediate mold 1 side.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is characterized in that an annular material relief groove is formed on the front and back surfaces of the mold so as to communicate with each product cavity, and when the mold is opened after molding, rubber molding is prevented. This invention relates to a method for releasing a rubber molded product molded in multiple molds using a three-piece mold consisting of a middle mold in which the product remains and is held, and a front side and a back side mold that sandwich the middle mold.

Although compression molding will be explained here as an example, the method of releasing a rubber molded product of the present invention is also applicable to mold molding such as transfer molding and injection molding.

<Prior Art> The conventional deburring force method for compression molded products was as follows.

First, a lump of rubber dough material that is slightly larger than the capacity of the product cavity is put into each product cavity of the lower mold (back side mold), the lower mold is raised, and the molds are matched with the middle mold, and then the middle mold is placed in the upper mold. (front side mold), close and clamp the mold, and perform mold vulcanization for a predetermined period of time. After vulcanization is completed, the mold is opened and the rubber molded product is released from the mold.

At this time, the rubber molded product 21 is usually retained in the middle mold 1 as shown in FIG. 7, and as shown in FIG. The mold was released by ejecting it with a protrusion jig 11).

<Problems to be Solved by the Invention> However, in the case of this method, as shown in FIG.
In most cases, particles containing 3 (filtered material) remained on the middle mold 1 and the rubber molded product 21 side. For this reason, it was necessary to clean the medium mold (remove adhered pars) after each one-cycle molding, and to remove pars from each rubber product part (of which there were many) after mold release.

In view of the above, it is an object of the present invention to provide a mold release method for rubber molded products that eliminates the need to remove pars from each rubber product part after mold release and facilitates the cleaning work of the medium size in each cycle. purpose.

<Means for Solving the Problems> The method for releasing a rubber molded product of the present invention solves the above problems with the following configuration.

An annular material release groove is formed on the front and back surfaces of the mold to communicate with the cavity of each product, and when the mold is opened after molding, the middle mold remains and holds the rubber molded product, and the front and back sides that sandwich the middle mold. A method of releasing a rubber molded product formed by molding multiple pieces using a three-piece die consisting of a mold, in which the annular ribs formed in the material relief grooves on both sides of the medium mold cannot be removed from the material relief grooves. It is characterized in that each rubber product part of the rubber molded product remaining and held in the middle mold is simultaneously ejected while the molded product is held in the middle mold to form a template.

<Example> Hereinafter, the present invention will be explained based on examples.

Note that parts that are the same as those in the conventional example are given the same reference numerals, and a part or all of the explanation thereof will be omitted.

1 to 6 show examples in which the method of releasing a rubber molded article of the present invention is applied to compression molding.

As shown in FIGS. 2 and 3, the mold used in the present invention has an annular material relief groove 2.3 that communicates with each product cavity portion C.
are formed on the front and back surfaces of the mold, and from the middle mold 1 in which the rubber molded product 21 remains and is held when the mold is opened after molding, and the upper and lower molds (front and back molds) 6.8 that sandwich the middle mold. It is a three-piece type.

In the same way as in the past, rubber dough material lumps are put into each product cavity C of the lower mold 8, and the mold is closed and clamped, that is, the rubber molded product 21 is molded in multiple pieces by compression molding.

When the mold is opened after vulcanization is completed by clamping the mold for a predetermined period of time, the rubber molded product 21 remains in the middle mold 1.

The ejection jig 11 transports the medium 1 to the ejection station where the ejection jig 11 and the upper and lower presser plates 1620 are arranged.
As shown in FIG. 1, a protruding plate 12 that is reciprocated by a driving device such as a cylinder or a crank device (not shown)
A plurality of protruding rods 13 are formed to protrude from the lower surface of the rubber molded product 21 in correspondence with the product portion 21a of the rubber molded product 21. In this embodiment, the protruding plate 12 is further provided with an upper holding plate 16 having a plurality of through holes 16a through which the protruding rods 13 can be inserted. in particular,
It is held by a plurality of hanging rods 17 that pass through the protruding plate 12, and a compression coil spring 19 is attached to the top of each hanging rod 17 via a spring case 18. Correspondingly below the upper presser plate 16, a lower presser plate 20 is provided which has a through hole 20a large enough to allow each product part to fall after being ejected.

With the mold being held between the upper and lower holding plates 16.2o at the ejecting station where the above device is arranged, the annular ribs 22.23 formed in the material relief grooves 2.3 on both sides of the medium mold 1 are used to release the material. Each rubber product part 21a of the rubber molded product 21 is simultaneously ejected from the groove 2.3 while being held so that it cannot be removed by an external force when ejecting the molded product.

Specifically, the medium size 1 is placed on the lower press plate 20 on the ward side, and the protrusion plate 12 is lowered by a drive device (not shown). Then, first, the upper presser plate 16 comes into contact with the surface of the middle mold 1. When the protruding plate 12 is further lowered, the upper holding plate 16 is elastically held by the upper and lower holding plates 16 and 20 due to the spring force of the compression coil spring 19 (see FIG. 4). At this time, the amount of wrapping for the material relief grooves 2.3 formed on the upper and lower sides of the medium mold 1 of the upper and lower presser plates 16.2° is usually set to be more than half of the groove width, as shown in FIG. Also, at this time, material release Tft
The width b of the annular channel communicating with 2.3 is 0.3 mm or less, and the depth d is 0.1 mm or less. Furthermore, from the viewpoint of facilitating deburring work, each material relief groove 2 formed in the medium 1
．． 3. It is desirable that the ends of each product part be connected to each other by a communication groove.

When the protruding plate 12 is further lowered, the protruding rod 1
3, each product part 21a of the rubber molded product 21 is projected, but the annular rib 22.2 formed in the material release groove 2.3
3 is partially pressed in such a way that it cannot be removed from the material release groove 2.3, so that the edges of each product portion including the annular ribs 22, 23 remain on the middle mold 1 side. Here, the parts of each product part are connected to each other, so there is no need to remove them individually.
- It can be removed with a very small number of operations (2 to 3 times). Naturally, each rubber product is ejected (released from the mold) from the medium mold 1 without any remaining particles.
Therefore, paris removal work is not necessary.

In the above embodiment, the rubber molded product was released by transporting the middle mold 1 to the ejection station located separately from the mold, but the upper mold 6 and the lower mold 8 were moved without transporting the middle mold 1. The mold release method of the present invention can be similarly implemented using a mechanism that can be alternately replaced with the upper presser plate 16 and the ball presser plate 20, respectively.

<Operations and Effects of the Invention> As described above, in the mold release method for rubber molded products of the present invention, the annular material relief groove is connected to the mold surface and connected to each product cavity.
Multi-cavity molding was performed using a three-piece mold consisting of a middle mold that is formed on the back side and retains the rubber molded product when the mold is opened after molding, and a front and back mold that holds the middle mold. A method of releasing a rubber molded product from a mold, in which the annular ribs formed in the material relief grooves on both sides of the medium mold are held in such a way that they cannot be separated from the material relief grooves, and each of the rubber molded products remaining and held in the medium mold is Since the rubber product part is simultaneously ejected and released from the mold, the following effects are achieved.

When the rubber molded product 21 is released from the middle mold 1 using the protrusion jig 11, each product part 21a of the rubber molded product 21 is ejected by the protrusion rod 13, but it is formed in the material release groove 2.3. Since the annular ribs 22 and 23 are held in a manner that cannot be removed from the material release groove 2.3, the edges of each product section including the annular ribs 22 and 23 remain on the middle mold 1 side. Here, if the parts of each product are connected to each other, there is no need to remove them individually;
It becomes possible to remove pars after cutting, making it easier to clean medium-sized objects. In addition, since each rubber product part is ejected (released from the mold) without any debris remaining, there is no need to remove debris from each product part.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing an example of an ejection jig used in the present invention, Fig. 2 is a schematic sectional view of a compression molding die consisting of a three-piece die to which the present invention can be applied, and Fig. 3 is a schematic sectional view showing an example of an ejection jig used in the present invention. "A cross section taken along the line III--III in Figure 2", Figure 4 is a sectional view of the main part immediately before mold release in the embodiment of the present invention, Figure 5 is a sectional view of the main part after mold release is completed, and Figure 6 is the top and bottom. Fig. 7 is an enlarged cross-sectional view of the main part showing the relationship between the presser plate and the middle mold, Fig. 7 is a cross-sectional view of the main part immediately before mold release in the conventional example, and Fig. 8 is a cross-sectional view of the main part after mold release is completed. Medium size, 2.3... Material relief groove, 6... Upper die (front side die), 8... Lower die (back side die), 11... Projection jig, 13... Projection rod, 16 ... Upper holding plate, 20... Ball holding plate, ... Rubber molded product, 22, 3... Annular rib, C... Product cavity part. Patent applicant diagram diagram

Claims (1)

[Claims] A middle mold in which an annular material relief groove is formed on the front and back surfaces of the mold so as to communicate with each product cavity, and a rubber molded product remains and is retained when the mold is opened after molding; A method for releasing a rubber molded product molded in multiple molds using a three-piece mold consisting of a front side mold and a back side mold that clamps an annular rib formed in a material release groove on both sides of the medium mold. The rubber molded product is released from the mold by simultaneously ejecting each rubber product part of the rubber molded product remaining in the medium mold while holding the rubber molded product in a state that the rubber molded product is not detached from the material relief groove. Mold release method.