JPS6044124B2 - Extrusion-press molding method - Google Patents

Description

[Detailed description of the invention] The present invention is extruded through a nozzle attached to an extruder.

The present invention relates to an extrusion-press molding method in which molten resin is cut into rod shapes or flat plate shapes, the blanks (hereinafter referred to as blanks) are placed in a mold, and then press molded. As shown in FIG. 1, a conventional blank cutting device cuts molten resin 2 extruded from a nozzle 1 attached to the tip of an extruder (not shown) in a direction perpendicular to the extrusion direction of the molten resin 2. The cutting blades 3 and 4 cut the molten resin 2 by sandwiching it from both sides.

As a result, as shown in FIG. 2, in the finished blank 5, linear cutting marks A remain on the center line C of the cut surfaces 5a and 5b on the cut surfaces 5a and 5b. Cutting marks remained on the surface of the product, making it look bad and reducing its value. The object of the present invention is to provide a molding method in extrusion-press molding that eliminates the above-mentioned drawbacks and leaves no cut marks on the surface of the molded product.

One embodiment of the present invention will be described with reference to FIGS. 3 to 5. A nozzle 11 is attached to an extruder (not shown) and extrudes molten resin 12 into a rod shape.

13 and 14 are cutting blades, and jewel cylinders 15 and 1 respectively.
6, and cuts the molten resin 12 from both sides in a direction perpendicular to the extrusion direction of the molten resin 12. The jewel cylinders 15 and 1
6 is when the cutting blades 13 and 14 are brought together as shown by the chain lines by changing the stroke or by changing the mounting position even if the stroke is the same, that is, the molten resin 1
When cutting 2, the cut surface 1 of the finished ivy blank 17
7a, the cut mark B is left at a position that is largely offset from the center line C. Then, on the cut surface 17a, a large area portion 18 and a small area portion 19 are separated from the cutting trace B.
It is divided into

Since the blank is formed as explained above, when performing the next step of press forming, as shown in FIG. Taking as an example a molded product that will become the back surface, we will explain the case where the upper mold moves vertically with respect to the fixed lower mold. , Bringing the volume portion of the cut surface 17a that includes the small cross-sectional area portion 19 into contact with the lower die 21 that forms the back surface or inner surface of the molded product, which will not cause any substantial problem even if cutting marks remain. When the upper mold 20 is lowered in the direction of the arrow d relative to the lower mold 21 to perform breath molding, the blank 17 is deformed as shown by the chain line 17b, and the cut mark B moves to the position shown by the arrow d. Cutting marks B will remain on the resin contact surface of the lower mold 21, that is, on the back side of the molded product, which has virtually no problems, and there will be no cutting marks B on the surface that contacts the upper mold 20. No O1
1. Also, as shown in FIG. 6, a pneumatic cylinder 31 to which a cutting blade 30 having a flat surface E is attached comes into contact with the side surface Z of the molten resin 33 extruded from the nozzle 32, and is attached to the pneumatic cylinder 34. The cutter blade 35 crosses the molten resin 33 from a direction perpendicular to the extrusion direction, and hits the flat surface E of the cutter blade 30 as shown by a chain line 35a, so that the cut surface of the blank is cut as shown in FIG. If the cut marks at 36 are made to coincide with the Z plane, the cut marks after molding will be less visible.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a blank cutting device in a conventional forming method, and FIG. 1 is a diagram of the cutting device. Figure 2 is a diagram of the molded blank. Figure 3 shows part 1 of the present invention.
FIG. 2 is a diagram of a blank cutting device showing an example. FIG. 4 is a diagram of a cut surface of a blank formed by the blank cutting device according to FIG. 3; FIG. 5 is an explanatory diagram of press molding according to the present invention. 6th
The figure shows another embodiment of the blank cutting device according to the present invention. 7th
The figure is a diagram of a cut surface of a blank formed by the blank cutting device of FIG. 6. FIG. 7 is a cross-sectional view 1-1 of FIG. 6. 11,
32... Nozzle, 12, 33... Molten resin, 13,
14, 30, 35... Cutting blade, 17... Blank, A
,B...cut trace.

Claims (1)

[Claims] 1 In an extrusion-press molding method in which the molten resin discharged from a nozzle attached to an extruder is cut into a rod shape or a flat plate shape, put into a mold, and then press molded, the molten resin is The molten resin is cut from both sides by two cutting blades operated by pneumatic cylinders from a perpendicular direction, and when the molten resin is cut, the two cutting blades are closer to the center line of the cut surface. The cut surface is divided into large and small area parts with the cut mark as a boundary, and when the cut molten resin is put into the mold, An extrusion-press molding method characterized by bringing the volume side including the small area portion of the cut surface into contact with a mold that forms the back side or internal surface of the molded product.