JPS60217126A - Extrusion molding method of irregular sectional product - Google Patents

Abstract

PURPOSE:To mold double racks from upper and lower surfaces by continuously inserting a core member formed in a wavy shape in the resin of an extrusion mold, and forming the rack between the upper and the lower surfaces. CONSTITUTION:A core member 1 formed in a wavy shape is inserted into an extrusion mold 2 for extruding resin, and the end is moved to between caterpillars 5 and 5. Then, the caterpillers 5 and 5 and a cooling tank 4 are driven, and melted resin is discharged into the mold 2. Thus, the member 1 is moved rightward, and resin mold of the prescribed shape is molded between the upper and the lower surfaces. The resin mold is guided to the tank 4 together with the member 1, cooled, solidified, and the rack of the resin mold product 6 is formed one by one on the upper and lower surfaces of the member 1, and fed rightward by the caterpillars 5, 5. The products 6, 6 are separated to become a complete product. Long rack is extrusion molded continuously, and two can be simultaneously molded to improve the productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an extrusion molding method for making a non-uniform cross-section product (one whose cross-sectional shape changes in the longitudinal direction) such as a rack from a resin molded product.

(Conventional technology) Racks and the like have traditionally been manufactured by injection molding or cutting.

For this reason, there have been problems in that the mold cost is high and the number of cutting steps is large, leading to high manufacturing costs.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and its object is to provide an extrusion molding method that allows racks and the like to be made from resin molded products at low cost.

(Structure of the Invention) The method of the present invention to achieve this object uses a core member processed so that an uneven surface of a predetermined shape is formed on an extrusion molded product, and an extrusion mold into which the core member is inserted, The resin supplied from the extruder is discharged into the extrusion mold, and the core member is moved within the extrusion mold to obtain a product with a non-uniform cross section on the core member. It is something to do.

(Example) Hereinafter, the method of the present invention will be specifically explained while explaining an apparatus (system) that implements the method of the present invention.

FIG. 1 is a block diagram showing an example of an apparatus for implementing the method of the present invention, and FIG. 2 is a perspective view showing the main parts of FIG. 1. Note that this embodiment is for manufacturing a rack having a shape as shown in FIG. In the figure, reference numeral 1 denotes a corrugated metal core member cut to a predetermined length, and the shape thereof is molded (for example, by press working) so as to match the tooth profile of the rack to be manufactured. Reference numeral 2 denotes an extrusion die, which is supplied with molten resin from a molding machine 3. Although not shown, molten resin is sent to the molding machine 3 via a conveying means such as a hopper or a screw.

The hole shape of the extrusion mold 2 is horizontal (see Fig. 2), and the upper and lower horizontal parts 2a, 2b are the width W of the non-toothed part (A in Fig. 3) of the rack to be manufactured. The vertical portion 2c in the middle regulates the width W2 of the tooth-shaped portion of the rack (8 in FIG. 3). This vertical part 2
Since the core metal member 1 is inserted through the vertical portion 2c
width < W (equivalent to 2) is selected to be slightly larger than the width Wo of the core metal member 1. Furthermore, the height H2 of the vertical portion 2C is selected to be approximately equal to the height Ho of the core member 1.

In addition, the extrusion mold 2 discharges the molten resin from the extrusion mold 2.
This is performed on both the upper and lower surfaces of the core metal member 1 inserted therein. Reference numeral 4 denotes a cooling tank for cooling and solidifying the resin, into which the core member 1 which passes through the extrusion mold 2 and has resin of a predetermined shape on both sides thereof is guided. 5 is a resin molded product (rack) after passing through the cooling tank 4
After passing through the caterpillar 5, the molded product 6 is separated from the core member 1,
Particularly long objects are wound up using a winding machine (not shown). Note that the core metal member 1 is reused.

Next, the operation of the above device will be explained.

First, insert the core metal member 1 into the extrusion mold 2 and let its tip reach between the caterpillars 5 (this is not necessary if you have a separate conveyance means for the core metal member 1. However, in this case (In order to avoid interference between the two, it is necessary to match the conveyance speed of the conveyance means with the conveyance speed of the caterpillar 5.) Next, the caterpillars 5 and the cooling tank 4 are driven, and the discharge of the molten resin into the extrusion mold 2 is started. As a result, the core metal member 1 moves to the right in FIG. 1, and resin moldings of a predetermined shape are formed on both the upper and lower surfaces thereof. This resin molded product is guided to a cold W tank 4 together with the core metal member 1, where it is cooled and solidified, and racks, which are resin molded products 6, are made one each at the top and bottom of the core metal member 1. It is sent out to the right in FIG. 1 by the caterpillar 5.

The resin molded product 6 is then separated from the core metal member 1 and further processed (cutting into a predetermined length, etc.) if necessary. Note that the resin molded product 6 and the core metal member 1 can be separated by curving the core metal member 1 or by pulling the non-toothed portion of the resin molded product 6 in the opposite direction to the core metal member 1. , can be easily achieved.

If the configuration as in the above embodiment is adopted, long racks can be continuously extruded and two racks can be formed, thereby increasing production efficiency. Further, the core metal member 1 can be simply a corrugated plate corresponding to the tooth profile of the rack, and the mold cost is lower than when injection molding is used.

Although the above embodiment was an example of a two-cavity mold, it is also possible to make one mold by changing the shape of the extrusion die 2 (providing only one of 2a and 2b). .

Furthermore, although the above embodiment was an example of producing a rack having the shape shown in FIG. 3, according to the method of the present invention, a perforated tape etc. as shown in FIG. 4 can be easily manufactured. You can also do it. In this case, for example, the core metal member 1 may be a flat plate with a constant thickness with protrusions alternately provided on the upper and lower surfaces, and the extrusion die 2 may have a hole shape such that the core metal member 1 can fit therein. A rectangular shape will be used.

(Effects of the Invention) As explained above, the method of the present invention includes a core member processed so that an uneven surface of a predetermined shape is formed on an extrusion molded product, and an extrusion molded product in which the core member is inserted and moved. Since resin molded products such as racks are obtained using molds, parts with complex shapes can be molded using core metal members.

Therefore, mold costs are reduced, and desired resin molded products can be produced at low cost. In addition, the core metal member is processed into a substantially corrugated plate shape,
By discharging the resin from the extrusion die onto both sides of the core member, production efficiency is doubled and racks can be produced at a lower cost.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an apparatus for realizing the method of the present invention, Fig. 2 is a perspective view showing the main parts of Fig. 1, and Fig. 3 is a resin molded product (rack) produced by the apparatus of Fig. 1. ), and FIG. 4 is a perspective view of a perforated tape that can be produced by the method of the present invention. 1... Core metal member 2... Extrusion mold 3... Molding machine 4... Cooling tank

Claims (2)

[Claims] (1) Using a core member processed so that an uneven surface of a predetermined shape is formed on the extrusion molded product and an extrusion mold into which the core member is inserted, resin supplied from the extruder is introduced into the extrusion mold. A method of extrusion molding a product with a non-uniform cross section, the product being discharged and moving the core member within the extrusion die so that the product with a non-uniform cross section is placed on the core member. (2) A substantially corrugated plate-like member is used as the core member, and resin is discharged from the extrusion mold onto both sides of the core member to obtain a rack as the resin molded product. A method for extrusion molding a product with a non-uniform cross section according to claim 1.