JPS5884748A - Method of reaction injection molding and mold therefor - Google Patents

Abstract

PURPOSE:To diminish working time in a reaction injection molding by a method wherein a runner gate and a flash connecting to a molded article are cut as forces are clamped after molding and the molded article is pushed out from the cavity after the forces are opened. CONSTITUTION:The die cavity formed by a top force 1 and the cavity 2a formed by a bottom force 2 is charged with material from a runner gate 15b and the material is cured to form a molded plate 5 with which the runner gate 6 and the flash 7 are connected. A main projecting pin 8 is projected, a movable plate 9 and movable side-plate projecting pins 14a, 14b, 14c that are fixed to the movable plate 9 and different from each other in length are lifted up, a movable side-plate 15 is moved progressively upward and the runner gate 6 and the flash 7 are cut by the cutting edge part 15a of the side plate 15. Then, a projecting accessory plate 10 does not move because as spring 12 is compressed. When the main projecting pin 8 projects further after the forces are opened, the movable plate 9 is lifted further, therefore, the projecting accessory plate 10 and the molded product projecting pin 13 also are lifted to project the molded plate 5 from the bottom cavity 2a.

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. Conventionally, the method for removing the runner gate and beam 9 connected to the molded product was to remove the molded product to which the runner gate and beam are connected from the mold, and then manually remove the molded product using a cutter knife or the like. It was carried out at work. but,
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 barrier to automation.

The present invention provides a reaction injection molding method that eliminates the drawbacks of the prior art described above, eliminates the need for a runner gate connected to a molded product and manual removal of burrs, and reduces the number of steps in reaction injection molding. The object is to provide a mold that can be used directly for carrying out the method.

The feature of the reaction injection molding method of the present invention is that after molding, the runner gate and burrs connected to the molded product are cut off while the mold remains closed, and then the mold is opened. The present invention is a reaction injection molding method in which the molded article is ejected from a mold cavity.

Further, the features of the reaction injection molding mold of the present invention include a cutting means for cutting the runner gate and beam connected to the molded product in a single stroke state in which the mold is clamped; A mold for reaction injection molding includes a runner gate and a protruding means for protruding the cut molded article from the mold cavity.

More details are as follows.

A runner gate and a beam connected to the molded product are fixed by a presser plate provided on the upper mold that is movable up and down, and a movable side plate that is movable up and down and has a cutting edge provided on the lower mold.
The movable plate fixed to the lower die is pushed up by the protrusion of the main ejection pin, and the movable side plate is pushed up in an inclined state by the movable side plate protrusion pins fixed to the movable plate and have mutually different lengths, and the movable side plate is cut. After opening the mold, the movable plate is further pushed up by the main ejection pin, which pushes up the ejection auxiliary plate attached to the movable plate via a coil spring and the molded product ejection pin fixed thereto, and lowers the movable plate. This is a reaction injection molding method in which the molded article that is in close contact with the mold cavity protrudes, and a mold used for carrying out the reaction injection molding method.

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 FIG. 4 is a sectional view taken along the line AA in FIG. 1, showing a state in which the burrs are cut, and FIG. 4 shows a state in which the mold is opened and the runner gate and the molded product from which the beams are cut are 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, a plate-shaped molded product 5 related to the molded product is molded by the mold 2 and the cavity 2a. It forms a mold cavity that can be used. Reference numeral 3 indicates a plate for attaching the upper mold to the upper mold 1, and reference numeral 4 indicates a plate for attaching the lower mold to the lower mold 2 via the lower mold fixing base 19.

Reference numeral 16 denotes a presser plate that is movably arranged on both sides of the upper mold 1 (Fig. 2), and numeral 15 is a presser plate that is arranged so as to be movable up and down on both sides of the cavity 2a of the lower mold 2 (Fig. 2). and cavity 2a
It is a movable side plate having a cutting edge portion 15a on the side, and a presser plate 16.
is positioned at a predetermined position by a guide pin 17 fixed to the upper mold 1, and the movable side plate 15 is positioned at a predetermined position by a positioning pin 21 fixed to the lower mold 2. Both the presser plate 16 and the movable side plate 150 are When the mold 1 and the holding plate 16 are pressed together downward by the coil spring 18 (fitted into the guide pin 17) and the mold is clamped (the state shown in Fig. 2), the A runner gate portion 15b (on the left side in FIG. 2) and an air vent 15C (on the right side in FIG. 2) are formed inside, connected to the mold cavity. The coil spring 18 is configured such that its pressing force is greater than the internal pressure when the material hardens.
Its spring constant is set. 9 is a movable 4fAlp with slightly different lengths, which is formed by pushing up the movable side plate 15 in an inclined state at its tip.
It is a movable plate that fixes the ejecting pins 14a, 14b, and 14c (there are three on each side, 14a is the longest and 14C is the shortest) and has a recess 9a for storing the ejecting auxiliary plate 10 described later. be.

A runner gate 6 connected to the plate-shaped molded product 5 and
The cutting means for cutting the burr 7 is composed of the above-mentioned presser foot 16, 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 ejecting auxiliary plate, 11 having a plurality of molded product ejecting pins 13 arranged and fixed on its upper surface in a position where the plate-shaped molded product 5 can be projected from the lower mold cavity 2a at the tips thereof. , the protruding auxiliary plate 10 is inserted into the recess 9a of the movable plate 9.
The fixed pin 12 for positioning at a predetermined position is a coil spring (fitted in the fixed pin 11) related to a spring inserted between the protruding auxiliary plate 1o and the movable plate 9. The pressing force of is smaller than the pressing force of the coil spring 18. 8 is a main protruding pin that is located below the movable plate 9 and pushes up the movable plate 9, and 20 is a guide pin that is fixed to the plate 4 for attaching the lower die and guides the movement of the movable plate 9.

The protruding means for protruding the plate-shaped molded product 5 (with the runner gate 6 and the burr 7 cut) from the cavity 2a includes the aforementioned movable plate 9, the main ejecting pin 8, and the ejecting auxiliary plate 1o. , and a molded product ejection pin 13 fixed to this ejection auxiliary plate 10.

In the mold of this embodiment configured as described above, 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 uniformly pressed against the movable side plate 15 provided on the lower mold 2 by the coil spring 18. Since this pressing force is greater than the internal pressure when the material is cured, there is no leakage of material between the holding plate 16 and the movable side plate 15. Moreover, since the movable side plate 15 is positioned by the positioning pin 21, no gap is created between the movable side plate 15 and the lower mold 2. Immediately after molding,
The plate-shaped molded product 5 (to which the runner gate 6 and burr 7 are connected).

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

First, the main ejection pin 8, which is the power source, is ejected from the pin 14a.
, 14b, and 14C lift the movable side plates 15 on both sides. Movable side plate protruding pins 14a, 14b, 14
C has different lengths, so the movable side plate 15
is in a slightly inclined state (lower in front and higher in depth in Figure 3) and is gradually lifted up. As the movable side plate 15 gradually moves upward, the liner gate 6 and burr 7 connected to the plate-shaped molded product 5 (9) are gradually moved by shear force by the cutting edge 15a of the movable side plate 15. be cut off. At this time, the presser plate 1 provided on the upper mold 1
6 moves upward integrally with the movable side plate 15 while holding down the runner gate 6 and the burr 7 via the coil spring 18.

In this way, by gradually moving the movable side plate 15, the runner gate 6 connected to the plate-shaped molded product 5 is moved.
Also, since the burr 7 is cut, an unreasonable load is not applied during cutting. In addition, at the time of this cutting, the coil spring 12 is pressed by the movable plate 9 and compressed, and the auxiliary protrusion plate 10 does not move.

Next, the procedure for protruding the plate-shaped molded product 5 from which the runner gate 6 and the burrs 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 1o is lifted (10). When the ejector auxiliary plate 10 is lifted, a molded product ejector pin 13 of uniform length is fixed to the handle.
is pushed up, and the plate-shaped molded product 5 can be projected from the lower mold 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 cut by protruding the main ejecting pin 8 which is the power source. , and the protrusion of the molded product 5 can be operated continuously.

Therefore, it is not necessary to remove the runner gate 6 and the burr 7 after the plate-shaped molded product 5 is taken out from the mold, and the time required for this can be significantly shortened.

According to this embodiment described above, the plate-shaped molded product 5
The runner gate 6 and the burr 7 connected to the runner gate 6 and the burr 7 (11) can be cut, and the molded product 5 can also be ejected using the same power source for cutting. In the case of the plate-shaped molded product 5, it was found that the cutting and removal work time can be shortened from the conventional 3 to 4 minutes/piece to 0.1 to 0.2 minutes/piece. It has also become easier to automate molding.

In addition, in this example, the plate-shaped molded product 5 according to FIG.
Although the method and mold of the present invention are not limited to the molding of plate-like molded products, they can also be applied to the molding of box molded products and other molded products. .

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, and FIG. Box (a) A perspective partial view of the molded product, FIG.
b) A perspective partial view of the molded product, showing the same parts. and,
22 is a box (a) molded product, and 23 is a box Φ) molded product. Both of these molded products are molded using a mold having the same structure as the mold shown in FIG. The cutting and ejection (12) of the molded product can be performed continuously.

As explained in detail above, according to the present invention, in the reaction injection molding method, after molding, the runner gate and burrs connected to the molded product are cut off while the mold remains closed, and then the mold is opened. Since the molded product is made to protrude from the mold cavity, a runner gate connected to the molded product and manual removal of burrs are eliminated, and the number of steps in reaction injection molding can be reduced. and a mold that can be used directly for carrying out this method can be provided.

[Brief explanation of drawings]

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 FIG. 4 is a sectional view taken along the line A-A in FIG. 1, showing a state in which the burrs have been cut, and FIG. , FIG. 5 is a perspective partial view showing a plate-shaped molded product (with the runner gate and flash connected) formed by the molding die according to FIG. 1, and FIGS. This shows another example of a molded product (with a runner gate and flash connected) formed by the method and molding die,
Figure 6 is a perspective partial view of the molded box (a), Figure 7 is
It is a perspective partial view of a box (b) molded product. , 1... Upper mold, 2... Lower mold, 2a... Capity, 5... Plate-shaped molded product, 6... Runner gate, 7.
...Flash, 8...Main ejection pin, 9...Movable plate, 1
o... Auxiliary plate for protrusion, 12... Coil spring, 13
... Molded product ejection pins, 14a, 14b, 14c
...Movable side plate protrusion pin, 15...Movable side plate, 1
6... Pressing plate. Agent: Patent attorney Kosaku Fukuda (and 1 other person) (14)

Claims (1)

[Claims] 1. In the reaction injection molding method, the mold is clamped after molding.
! ! 1. A reaction injection molding method characterized in that the runner gate and the tab 9 connected to the molded product are cut, the mold is opened, and the molded product is ejected from the mold cavity. 2. In a mold for reaction injection molding, a runner gate connected to a molded product and a cutting means for cutting off burrs while the mold is still clamped; A mold for reaction injection molding, comprising a protruding means protruding from the cavity. 3. The cutting means includes a presser plate attached to the upper die so as to be movable up and down, a movable side plate having a cutting blade section and attached to the lower die so as to be movable up and down, and the movable side plate being pushed up in an inclined state. 3. The reaction injection molding mold according to claim 2, which comprises a plurality of movable side plate protruding bins having different lengths and fixed to a movable plate. 4. The ejection means includes a movable plate, a main ejection pin that pushes up the movable plate, an auxiliary ejection plate attached to the movable plate via a spring, and a plurality of molded products fixed to the auxiliary ejection plate. A mold for reaction injection molding according to claim 2, which comprises an ejection bottle.