JPH0729334B2 - In-mold mold die clamping device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a clamp device that reliably fixes a transfer film to a movable mold of an in-mold molding die without damaging it with a simple mechanism.

[Prior art]

Conventionally, a long transfer film on which a design or a functional thin film is formed is sent to a predetermined position in a mold for injection molding, the mold is closed, and molten resin is injected into the mold to obtain a molded product. There is a so-called in-mold molding method in which the pattern of the transfer film or the functional thin film is brought into close contact with the surface of the molded product simultaneously with the formation. In the in-mold molding method, as a clamp device for fixing the transfer film to the mold, as described in Japanese Utility Model Laid-Open No. 58-128015, the transfer film is a female mold with a frame that works in conjunction with the ejector on the female mold side. A device for pressing and fixing to the peripheral edge, or as described in Japanese Utility Model Publication No. 62-17268, a clamp while the movable clamp member provided on the movable mold is pressed against the movable mold by the action of a push rod provided on the fixed mold. There has been a clamp device that fixes a transfer film between a member and a movable die and sinks the clamp member into the fixed die.

[Problems to be Solved by the Invention]

However, in the former clamp device, the shape of the frame body must be a shape that conforms to the contour of the female mold, and one of the steps for aligning the transfer film along the wall surface of the female mold by vacuum suction or the like is performed. It is a responsibility. Therefore, it is very difficult to adjust the clamp member in the die having a shape in which the mating surface of the female die and the male die, that is, the parting surface is complicatedly changed. In addition, when the mold type uses a slide core, the clamp member is a frame and therefore interferes with the slide core. It was impossible. Furthermore, since the clamp member is connected to the ejector, the forward and backward strokes and speed of the clamp member are all linked to the ejector. Therefore, when the parting surface has a shape that is largely deformed, it is difficult to follow the transfer film and it is extremely difficult to adjust the transfer film. The latter clamp device has many design restrictions when the fixed mold is a protruding mold, and the sliding stroke of the clamp member can be at most about 20 mm. At the beginning of the process of opening the mold for in-mold molding, the state in which the clamp member presses the transfer film to the movable side ends, and then the transfer film is opened, so the transfer film is removed from the molded product remaining on the fixed mold side. When peeling, the transfer film is pulled toward the molded product, causing waviness in the transfer film, and because the transfer film rubs against the guide bar or positioning sensor provided above the mold, it should be transferred next. Problems such as scratching or peeling off of new patterns occur. The present invention solves the above-mentioned drawbacks and makes it possible to reliably align the transfer film with the parting surface while maintaining the positioning accuracy even for a mold having a parting surface with a complicated shape. An object is to provide a clamp device for a mold for molding.

[Means for Solving the Problems]

The present invention is configured as follows to achieve the above object. That is, the clamp device for the in-mold molding die of the present invention inserts the transfer film between the fixed mold and the movable mold of the mold, and transfers the design of the transfer film onto the molded product simultaneously with the injection of the molten resin. In the mold for molding, a plurality of clamp bars provided on the movable mold are configured to operate so as to sequentially sandwich the transfer film. The present invention will be described in more detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a clamp device for an in-mold molding die of the present invention, and FIG. 2 is a plan view thereof. 3 to 5 are sectional views showing other embodiments. 1 is a fixed type, 2 is a movable type, 3 is a clamp bar, 4 is a clamp bar tension rod, 5 is a spring, 6 is a shock absorber, 7 is an operating plate, 8 is a rod, 9 is a transfer film, and 10 is a cavity. Show. A plurality of clamp bars 3 are formed on the movable die so that they can slide independently of each other on the movable die 2. Normally, the clamp bar 3 should be arranged at right angles to the direction in which the transfer film 9 is fed (see FIGS. 1 and 2). In order to operate the clamp bar 3 so as to sandwich the transfer film 9 in order, the following configuration may be adopted. Movable type 2
The clamp bar 3 is connected to one end of a clamp bar pulling rod 4 penetrating therethrough, and a transfer film 9 is sandwiched between the clamp bar 3 and the movable mold 2 by a spring 5 provided on the clamp bar pulling rod 4. . The other end of the clamp bar pulling rod 4 is configured so as to hit the operating plate 7. Further, the operating plate 7 is pushed and moved by the rod 8 to push out the clamp bar pulling rod 4. For moving the rod 8 forward and backward, it is preferable to use a hydraulic ejector (not shown) provided in the injection molding machine. Further, a hydraulic cylinder or an air cylinder may be incorporated in the mold to move the operating plate 7.

[Action]

When the mold is opened, the rod 8 advances and pushes the operating plate 7, so that the clamp bar pulling rods 4a and 4b are also pushed out, and a gap is generated between the movable mold 2 and the clamp bars 3a and 3b, so that the transfer film 9 is formed. Is released (see FIG. 3a). The forward force of the rod 8 must be stronger than the resultant force of the springs 5a, 5b, 5c. Subsequently, the transfer film 9 is sent out, a new pattern portion is guided to a predetermined position of the mold, the cavity and the pattern are registered, and the transfer film 9 is fixed. To fix the transfer film 9, first, the rod 8 pushing up the operation plate 7 is retracted. Clamp bar tension rod
Clamp bars 3a and 3b are pulled back by the extension force of springs 5a and 5b built in 4a and 4b and auxiliary spring 5c, and transfer film 9 is fixed to movable die 2. At this time, the upper clamp bar 3a and the lower clamp bar 3b are sequentially operated. Because, if the upper clamp bar 3a and the lower clamp bar 3b retreat at once at the same time, a large impact is applied to the transfer film 9, and the pattern formed on the transfer film 9 is cracked or scratched on the transfer film 9. Is caused. Therefore, the shock absorber 6 may be provided behind the upper clamp bar pulling rod 4a. When the rod 8 retracts, the lower clamp bar 3b retracts due to the extension force of the spring 5b, and immediately the transfer film 9b
Is fixed to the movable mold 2 (see FIG. 3b). Further, the operation speed of the upper clamp bar 3a is reduced by the action of the shock absorber 6, and the upper clamp bar 3a is gently pulled in. By sequentially operating the clamp bar 3 in this manner, the transfer film 9 is not damaged, and even if the parting surface is greatly deformed, the transfer film 9 is not damaged.
Can be easily followed (see FIG. 3c). Further, as another means for sequentially operating the clamp bars 3, for example, by changing the length of the clamp pulling rod 4 to change the operation stroke, it can be realized without using the shock absorber 6 (No. 1). (See Fig. 4). Alternatively, springs 5a and 5b having different strengths may be adopted. After the transfer film 9 is fixed on the surface of the movable mold 2 in this way, the mold is closed and the molten resin is injected into the cavity 10 formed between the movable mold 2 and the fixed mold 1 to perform molding. The mold is opened after a certain cooling time (see FIG. 5), and one cycle of in-mold molding is completed. For convenience of explanation, a mold having one cavity 10 is taken as an example, but the number of cavities 10 is not limited to one.

【Example】

In order to transfer the design to the inner surface of the arc shape, clamp bars were arranged above and below the movable mold in the in-mold molding die. Each of the clamp bars is actuated by the extension force of the spring, and the clamp plates are pushed out by pushing the actuation plate using the ejector of the injector. Further, a shock absorber is built in the upper clamp bar pulling rod portion so that it can be pulled in more slowly than the operating speed of the lower clamp bar. First, open the mold and push out the clamp bar larger than the convex part on the movable side so that the transfer film passing between the clamp bar and the movable mold does not rub against each other and the pattern of the transfer film and the cavity of the movable mold Alignment was done and then the clamp bar was retracted. The lower clamp bar immediately sandwiched the transfer film, and the upper clamp bar was gently retracted by the action of the shock absorber, and the film was clamped while retracting the transfer film from the film delivery side of the foil feeder. In this way, the transfer film could be made to follow the greatly curved parting surface without damaging the pattern formed on the surface of the transfer film. Next, the mold was closed, the molten resin was injected, and after the resin was cooled, the mold was opened to obtain a beautiful in-mold molded product in which the pattern was transferred to the inner surface of the arc shape.

【The invention's effect】

The clamp device of the mold for in-mold molding of the present invention,
A plurality of clamp bars are configured to sandwich the transfer film in order, and the clamp bars are not connected to the ejector of the injection molding machine, and since the structure is simple,
The pinching strength, operating stroke adjustment, operating speed adjustment, etc. can be performed extremely easily. Further, the mold can be designed without difficulty in the structure having the slide core.
Therefore, transfer can be performed to a mold having a parting surface with a complicated shape.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a clamp device for an in-mold molding die according to the present invention. FIG. 2 is a plan view thereof, and FIGS. 3 to 5 are sectional views showing other embodiments. 1 ... Fixed type, 2 ... Movable type, 3 ... Clamp bar, 4
…… Clamp bar tension rod, 5 …… Spring, 6 …… Shock absorber, 7 …… Operating plate, 8 …… Rod, 9 …… Transfer film, 10 …… Cavity.

Claims (2)

[Claims] 1. An in-mold molding die in which a transfer film is sandwiched between a fixed die and a movable die of a die, and a pattern of the transfer film is transferred onto a molded article at the same time as injection of a molten resin. A clamp device for an in-mold molding die, wherein a plurality of clamp bars provided are operated so as to sandwich the transfer film in order. 2. The in-mold according to claim 1, wherein the clamp bar is actuated by an extension force of a spring, and the shock absorber is used as a reduction mechanism to sequentially actuate each clamp bar. Clamping device for molding dies.