JPH0251727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reaction injection molding method and a mold for the same, and particularly to a reaction injection molding method and a mold for the reaction injection molding aimed at reducing the number of steps in reaction injection molding.

In reaction injection molding, when a material is injected into a mold, a runner gate section is generally attached to the mold in order to uniformly inject the material into the mold. Further, in order to remove air within the mold, an air vent is provided on the downstream side of the mold (opposite the injection port). Therefore, the molded product is connected to the excess material (called burrs) that has flowed out to the runner gate and air vent. The conventional method for removing the runner gate and burrs connected to the molded product is to remove the runner gate and the molded product to which the burrs are connected from the mold, and then remove the burr manually using a cutter knife or the like. Was. However, this method is time consuming, which not only poses a problem in terms of reducing the number of man-hours in reaction injection molding, but also poses a problem for automation.

The present invention eliminates the above-mentioned drawbacks of the prior art,
To reduce the number of man-hours in reaction injection molding by removing runner gates and burrs connected to a molded product by cutting the mold with the mold clamped, without putting an undue burden on it, without having to do it manually. The object is to provide a reaction injection molding process and a mold that can be used directly for carrying out this process.

The structure of the reaction injection molding mold according to the present invention is that the reaction injection molding mold is equipped with an upper mold and a lower mold for molding a mold cavity. a movable side plate that is movably attached and has a cutting edge; a plurality of movable side plate protrusion pins of different lengths that are fixed to the movable plate so that the movable side plate can be pushed up in an inclined state; It has an auxiliary ejection plate attached to the movable plate via a spring, and a plurality of molded product ejection pins fixed to the auxiliary ejection plate.

Further, the reaction injection molding method according to the present invention is characterized in that the reaction injection molding method in which a mold cavity formed by an upper mold and a lower mold is filled with a material and molded, includes at least an upper mold, a lower mold, and a cutting edge. a movable side plate that is attached to the lower die so that it can move up and down, a plurality of movable side plate ejection pins of different lengths that are fixed to the movable plate, and an ejection auxiliary that is attached to the movable plate via a spring. Using a reaction injection mold having a plate and a plurality of molded product ejection pins fixed to this auxiliary ejection plate, after molding, lift the movable plate while the mold remains closed, and remove the plurality of movable pins. The movable side plate is gradually lifted up in an inclined state by the side plate ejection pin, and the remaining material connected to the molded product is cut by the cutting blade provided on the movable side plate, and then the mold is opened. In the reaction injection molding method, the ejecting auxiliary plate is lifted by further lifting the movable plate, and the ejecting pin is accordingly ejected to eject the molded product from the mold cavity.

The present invention will be explained below with reference to Examples.

FIG. 1 is a side view showing an example of a molding die used for carrying out a reaction injection molding method according to an embodiment of the present invention, and FIGS. 2 to 4 are a side view showing an example of a molding mold according to FIG. Fig. 2 shows the state immediately after the plate-shaped molded product is molded, and Fig. 3 shows the runner gate connected to the molded product with the mold clamped, and The state where the burr has been cut is
Figure 4 shows the runner gate and
FIG. 2 is a sectional view taken along the line A-A in FIG. 1, showing the molded product with the burrs cut and projected. FIG. 5 is a partial perspective view showing a plate-shaped molded product (with a runner gate and a burr connected) formed by the mold shown in FIG. 1. FIG.

In each figure, the same numbers indicate the same parts.

First, the structure of the reaction injection molding mold (hereinafter simply referred to as mold) of this embodiment will be explained using FIGS. 1 and 2. 1 is an upper mold, 2 is a lower mold, and 2a is a cavity formed in the lower mold 2. When the molds are clamped, the upper mold 1 and the cavity 2a form a plate-shaped molded product 5 related to the molded product. It forms a mold cavity that can be used. 3 is an upper mold mounting plate attached to the upper mold 1, and 4 is a lower mold mounting plate attached to the lower mold 2 via the lower mold fixing base 19.

Reference numerals 16 and 15 indicate presser plates that are movably disposed on both sides of the upper die 1 (Fig. 2) in a vertically movable manner, and 15 are movably disposed on both sides of the cavity 2a of the lower die 2 (Fig. 2) It is a movable side plate having a cutting edge 15a on the side of the cavity 2a, and the holding plate 16 is connected to the movable side plate 15 by a guide pin 17 fixed to the upper mold 1.
are positioned at predetermined positions by positioning pins 21 fixed to the lower mold 2, and the presser plate 1
6 and the movable side plate 15 are both the upper die 1 and the presser plate 16.
When the coil spring 18 (fitted into the guide pin 17) inserted between the Inside, connected to the mold cavity, there are a runner gate part 15b (left side in Figure 2) and an air vent 15c (right side in Figure 2).
is beginning to form. Said coil spring 1
8, its spring constant is set so that its pressing force is greater than the internal pressure when the material hardens. Reference numeral 9 denotes movable side plate protruding pins 14a, 14 having slightly different lengths and whose tips can push up the movable side plate 15 in an inclined state.
While fixing b and 14c (there are three on each side, 14a is the longest and 14c is the shortest),
A recess 9a for storing an auxiliary protrusion plate 10, which will be described later.
It is a movable plate with a

Runner gate 6 connected to plate-shaped molded product 5
The cutting means for cutting the burr 7 includes the aforementioned presser foot 16 and a movable side plate 15 having a cutting edge portion 15a.
and movable side plate protruding pins 14a, 14b, and 14c fixed to the movable plate 9.

Reference numeral 10 denotes an ejection auxiliary plate, 11, which has a plurality of molded product ejection pins 13 arranged and fixed on its upper surface at a position where the plate-shaped molded product 5 can be projected from the lower die cavity 2a at the tips thereof. 12 is a fixed pin for positioning the ejection auxiliary plate 10 at a predetermined position in the recess 9a of the movable plate 9; 12 is the ejection auxiliary plate 10;
A coil spring (fitted into the fixed pin 11) is a spring inserted between the movable plate 9 and the movable plate 9,
The pressing force of this coil spring 12 is smaller than the pressing force of the coil spring 18. 8 is a main protrusion pin located below the movable plate 9 and pushes up the movable plate 9; 20 is a guide pin fixed to the lower die mounting plate 4 and guides the movement of the movable plate 9.

The plate-shaped molded product 5 (with the runner gate 6 and burrs 7 cut off) is placed in the cavity 2a.
The protruding means protruding from the movable plate 9 mentioned above,
It is composed of a main ejection pin 8, an auxiliary ejection plate 10, and a molded product ejection pin 13 fixed to the ejection auxiliary plate 10.

In the mold of this embodiment configured in this way, the material is injected into the runner gate part 15b of the clamped mold, filled into the mold cavity formed by the upper mold 1 and the cavity 2a, and after hardening is formed into a plate shape. It becomes item 5 (Figure 2). During molding, the presser plate 16 provided on the upper mold 1 is pressed against the lower mold 2 by the coil spring 18.
It is pressed uniformly against the movable side plate 15 provided for. Since this pressing force is greater than the internal pressure when the material is cured, there is no leakage of material from between the holding plate 16 and the movable side plate 15. In addition, the movable side plate 1
5 is positioned by the positioning pin 21, so there is no gap between the movable side plate 15 and the lower mold 2. Immediately after molding, the runner gate 6 and the burr 7 are connected to the plate-shaped molded product 5.

Next, the procedure for cutting the runner gate 6 and the burr 7 will be explained using FIG.

First, when the main ejection pin 8, which is the power source, is ejected, the movable plate 9 in contact with it is lifted, and the movable side plate ejection pins 14a, 14b, 14c fixed to the movable plate 9 The movable side plate 15 is lifted. Since the movable side plate protruding pins 14a, 14b, and 14c have different lengths, the movable side plate 15 is gradually lifted up in a slightly inclined state (in Fig. 3, the front side is lower and the depth is higher). It will be done. Movable side plate 15
The runner gate 6 connected to the plate-shaped molded product 5 by gradually moving upward, and
The burr 7 is gradually cut by the cutting edge 15a of the movable side plate 15 by shearing force. At this time, the presser plate 16 provided on the upper die 1 is pressed against the coil spring 1.
It moves upward together with the movable side plate 15 while holding down the runner gate 6 and the burr 7 via the movable side plate 15. In this way, by gradually moving the movable side plate 15, the runner gate 6 and the burr 7 connected to the plate-shaped molded product 5 are cut, so that an unreasonable load is not applied during cutting. do not have. Note that during this cutting, the coil spring 12 is pressed by the movable plate 9 and compressed, and the ejecting auxiliary plate 10
is never moved.

Next, the procedure for protruding the plate-shaped molded product 5 from which the runner gate 6 and the burr 7 have been cut out from the cavity 2a will be explained using FIG. 4. After the runner gate 6 and the burr 7 are cut, the mold is opened as shown in FIG. Thereafter, when the main ejector pin 8, which is the same power source as described above, is further ejected, the movable plate 9 is further lifted, and the ejector auxiliary plate 10 is lifted. When the ejecting auxiliary plate 10 is lifted, a molded product ejecting pin 13 of a uniform length fixed thereto is pushed up, allowing the plate-shaped molded product 5 to be ejected from the lower die cavity 2a.

To return the mold to its pre-molding state, first move the main ejector pin 8 downward, and then close the mold.

As described above, by using the mold of this embodiment, the runner gate 6 and burr 7 connected to the plate-shaped molded product 5 can be Cutting and ejection of the molded product 5 can be performed continuously.

Therefore, there is no need to remove the runner gate 6 and the burrs 7 after the plate-shaped molded product 5 is taken out of the mold, and the time required for this can be significantly shortened.

According to this embodiment described above, the runner gate 6 and the burr 7 connected to the plate-shaped molded product 5 can be cut in the mold, and the same power source used for cutting can also be used to prevent the molded product 5 from protruding. The runner gate 6 and burr 7
Cutting and removal is carried out in a mold-clamped state without imposing an unreasonable burden, and the cutting and removal time is approximately 5.
As an example, the conventional 3-4 minutes/piece is reduced to 0.1-0.2
I found out that it can be shortened to 1 minute/piece. It has also become easier to automate molding.

In this example, the case of molding the plate-shaped molded product 5 shown in FIG. It can also be applied to molding products such as products and other molded products.

Figures 6 and 7 show other examples of molded products (with the runner gate and flash connected) formed by the method and mold of the present invention. 7 is a perspective partial view of the molded box a, and FIG. 7 is a partial perspective view of the molded box b.

In each figure, parts given the same numbers as in FIG. 5 are the same parts. 22 is a box a molded product, and 23 is a box b molded product. Both of these molded products are molded using a mold having the same structure as the mold shown in FIG. It is capable of continuous operation of cutting and ejecting the molded product.

As explained in detail above, according to the present invention,
In a reaction injection molding method using a mold for reaction injection molding, after molding, the movable plate is lifted up while the mold remains closed, and the movable side plate is gradually tilted by the plurality of movable side plate ejection pins. by the cutting blade provided on the movable side plate,
After cutting the excess material connected to the molded product, the mold is opened, and the ejecting auxiliary plate is lifted by lifting the movable plate, and the ejecting pin is ejected to move the molded product into the mold. Since the runner gate and burrs are made to protrude from the cavity, the runner gate and burrs connected to the molded product can be removed without manual work, by cutting the mold with the mold clamped and without applying excessive stress. The number of man-hours in reaction injection molding can be reduced.
A reaction injection molding process and a mold for direct use in carrying out the process can be provided.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of a molding die used for carrying out a reaction injection molding method according to an embodiment of the present invention, and FIGS. 2 to 4 are a side view showing an example of a molding mold according to FIG. Fig. 2 shows the state immediately after the plate-shaped molded product is molded, and Fig. 3 shows the runner gate connected to the molded product with the mold clamped, and The state where the burr has been cut is
Figure 4 shows the runner gate and
A sectional view taken along the line A-A in FIG. 1 and FIG. 5 respectively show a protruding state of the molded product with the burrs cut off, and FIG. A perspective partial view showing the runner gate and the state in which the burr is connected, No. 6 to
FIG. 7 shows another example of a molded product (with the runner gate and flash connected) formed by the method and mold of the present invention, and FIG. A perspective partial view of a molded product,
FIG. 7 is a perspective partial view of the molded box b. 1... Upper mold, 2... Lower mold, 2a... Cavity, 5... Plate molded product, 6... Runner gate,
7...Flash, 8...Main ejection pin, 9...Movable plate, 10...Auxiliary ejection plate, 12...Coil spring, 13...Molded product ejection pin, 14a, 14
b, 14c...Movable side plate protrusion pin, 15...
Movable side plate, 16...presser plate.

Claims (1)

[Scope of Claims] 1. A reaction injection molding mold comprising an upper mold and a lower mold forming a mold cavity, comprising: a presser plate attached to the upper mold so as to be movable up and down; and a presser plate attached to the lower mold so as to be movable up and down. a movable side plate provided with a cutting edge; a plurality of movable side plate protruding pins of mutually different lengths fixed to the movable plate so as to be able to push up the movable side plate in an inclined state; and a spring mounted on the movable plate. A mold for reaction injection molding, comprising: an auxiliary ejection plate attached to the auxiliary ejection plate; and a plurality of molded product ejection pins fixed to the auxiliary ejection plate. 2. In a reaction injection molding method in which a mold cavity formed by an upper mold and a lower mold is filled with material and molded, at least an upper mold, a lower mold, and a cutting blade, which is attached to the lower mold so as to be movable up and down, is used. A movable side plate, a plurality of movable side plate ejection pins of different lengths fixed to the movable plate, an auxiliary ejection plate attached to the movable plate via a spring, and a plurality of pins fixed to the auxiliary ejection plate. Using a reaction injection molding mold having a pin for ejecting a molded product, after molding, lift the movable plate with the mold closed, and tilt the movable side plate by the plurality of pins for ejecting the movable side plate. The remaining material connected to the molded product is cut by the cutting blade provided on the movable side plate, the mold is opened, and the movable plate is further lifted to eject the molded product. 1. A reaction injection molding method comprising lifting an auxiliary plate and projecting an ejecting pin accordingly to eject the molded product from the mold cavity.