JPH0673868B2 - Manufacturing method of long molded products by continuous injection molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long molded product such as a wiring duct by using a plastic injection molding method.

[0002]

2. Description of the Related Art Wiring ducts are, for example, as shown in FIG. 3, both side walls 32, 3 of a bottom surface 31 of a long U-shaped body.
34 are continuously drilled in the wire 3, and fitting portions 38, 39 for fitting with the lid 37 are formed at the upper edge portions of the side walls 32, 33. 38 and 39 have portions that enter inwardly from the extended surfaces of the side walls 32 and 33. Both side walls 32 and 33 are parallel to each other in the use state where the main body is fitted with the lid 7, but in the state where the lid 37 is not fitted, in order to obtain frictional force at the time of fitting, the both side walls 3
The upper edges of Nos. 2 and 33 are formed to be slightly expanded.

The wiring duct having such a shape is conventionally manufactured by performing the entire molding process by the extrusion molding method and then punching out the wire lead-out ports 34 ,. However, according to such a manufacturing method, there is a problem that troublesome post-processing such as chamfering of the processed surface of the wire drawing port 34 is required. Therefore, in order to solve this problem, the present applicant has succeeded in forming a long wiring duct by continuously molding the unit molded products of the duct by injection molding and joining the respective end portions thereof in order by joining. A manufacturing technique is proposed (Japanese Patent Laid-Open No. 63-283411).

[0004]

By the way, according to the technique of Japanese Patent Laid-Open No. 63-283411 mentioned above, the injection-molded unit molded product is taken out from the mold, and its rear end is the tip of the next unit molded product. After moving to the position where it overlaps with the section,
At the same time that the next unit molded product is injection molded, the two are joined at the same time, so there is a temperature difference between the main body of the unit molded product that was previously injected and the joint. It will be cooled. When there is such a temperature difference, a shrinkage force or the like acts on the joint portion together with the shape of the portion, and the joint portion warps or shrinks. as a result,
There remains a problem that the obtained long wiring duct is entirely curved along the longitudinal direction.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a joint portion between an injection-molded unit-molded product and a unit-molded product to be newly injected next. It is an object of the present invention to provide a method capable of removing a contracting force acting on the above and thereby producing a long product with less overall bending.

[0006]

Means for Solving the Problems The production method of the present invention comprises:
After the injection-molded unit molded product is taken out of the mold and translated in one direction (longitudinal direction of the long molded product) by a predetermined distance, when the next unit molded product is injection molded, It is characterized by applying a predetermined tensile force to the joint portion when joining the front end portion in the moving direction and the rear end portion of the previously molded unit molded product along the above direction.

[0007]

[Operation] The joint between the injection-molded unit molded product and the next newly injected unit molded product has the property of contracting when cooled, and the action force due to the contraction is mainly in the direction of molding. That is, the long product works along the extending direction, but by applying a tensile force F to the joining portion along the shrinking direction of the joining portion W as shown in FIG. 2 at the time of joining. The shrinkage force after cooling and the stress due to the tensile force F applied at the time of joining cancel each other out.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an apparatus used for carrying out the method of the present invention. The mold device 1 is for molding a unit molded product of a wiring duct, and an injection molding machine 2 for injecting a molten resin such as plastic into the mold device 1 above the mold device 1.
Are provided, and the unit moldings of the wiring duct are successively molded by the two devices 1 and 2.

A feeder 3 for pulling an injection-molded unit molded article out of the mold and translating it by a predetermined distance is provided on the side of the mold apparatus 1. Further, a pulling device 4 is arranged on the downstream side of the feeding device 3. The feeding device 3 is the table 5 of the support base 5 of the mold device 1.
After moving on a, first, at a predetermined position of the mold device 1, the unit molded product injection-molded by the mold device 1 is held by being sandwiched by the upper and lower clampers 3a and 3b, and in this state When moving in parallel and the rear end of the injection-molded unit molded product reaches the joining position with the tip of the next injection-molded unit molded product, the movement is stopped and the unit waits at that position. Then, after the injection molding of the next unit molded product is completed, the molded products D are sequentially sent by repeating the reciprocating movement of returning to the original position. When the pulling operation described below is performed at the time of joining, the upper clamper 3a moves upward, and the molded product D is only placed on the lower clamper 3b.

The pulling device 4 is provided with a clamp part 41 and a moving mechanism part 42 for translating the clamp part 41 in parallel with the feeding direction of the molded product D. The clamped portion 41 is held firmly in the clamp portion 41 every time the sheet is fed, and the push pin 42a is projected in this state, so that the clamp portion 41 is moved by a minute distance d and a tensile force is applied to the molded portion D. Is configured to give. That is, the push pin 42
The reference character a moves to the left and right in the drawing when air is supplied to and exhausted from the air cylinder 42b, and its tip is fixed to the clamp part 41 by screwing or the like. When applying a pulling force, compressed air is supplied to the air silling 42b so that the push pin 42a projects.
By exhausting the air cylinder 42b before the next operation,
The push pin 42a retracts, and the clamp portion 4a
The whole 1 is configured to move left and right. 4
Reference numeral 2c is a stopper for restricting the movement of the clamp portion 41. Further, the clamp part 41 is configured to maintain an open state when the molded product D is being transferred by the feeding device 3, and the driving of the clamp part 41 is also controlled by pneumatic equipment such as an air cylinder (not shown). To be done.

As the mold device 1, for example, the mold device described in the detailed description of the invention of the above-mentioned Japanese Patent Laid-Open No. 63-283411 is used. Now, the operation of the method of the present invention and its operation will be described using the apparatus described above. First, the unit molded product molded in the mold device 1 is extracted by the feeding device 3 and moved. By this movement, the rear end of the injection-molded unit molded product is arranged at a position corresponding to the front end of the unit molded product to be subsequently injection-molded by the mold apparatus 1.
In this state, injection molding of the next unit molded product is performed, but at this time, the end of the previously molded product and the end of the new molded product are integrated by fusion bonding.

Next, after the injection molding of the new molded product is completely completed, the new molded product portion is held and moved by the feeding device 3, and the next new unit molded product is injection molded. By repeating such a procedure in sequence, the unit molded products that are continuously molded in the mold apparatus 1 are sequentially joined by joining, and have a shape similar to that of the shape shown in FIG. A wiring duct can be obtained.

Here, in the embodiment of the present invention, when the injection-molded unit-molded product and the unit-molded product to be newly injected next are joined, the molded product D is formed by using the pulling device 4.
Is moved by a predetermined distance d in the feeding direction, as shown in FIG. 2, the molded product D1 and the new molded product D2
A predetermined tensile force F is applied to the joint portion W with. By applying such a tensile force F, even if a contracting force acts on the joint portion W at the time of cooling, the acting force is the same as the tensile force F applied at the time of joining. It is canceled by the corresponding stress, and the biased stress does not act on the joint W. As a result, in the molded wiring duct, there is no warp or sink mark in the joint W, and as a result, a wiring duct without bending in the longitudinal direction can always be manufactured stably.

The tensile force F applied to the joint W, that is, the minute movement amount d of the molded product D, was determined based on various conditions such as the area of the joint W and its shape, and the heat shrinkage rate of the injected resin. It is possible to create various data in advance by selecting the optimum value, or
It may be calculated from these conditions at the time of design.

In addition to the duct duct for wiring, the method of the present invention can of course be applied to the case of manufacturing other long products such as edge ornaments of floor mats by continuous injection molding.

[0016]

As described above, according to the method of the present invention, at the time of joining an injection-molded unit molded product and a unit molded product to be newly injected next, a pulling force is applied to the bonded portion. As a result, even if a contracting force acts on the joint when it cools, the acting force cancels out with the stress due to the pulling force, preventing the joint from warping or sinking. it can. This eliminates problems such as the long product that has been molded is generally curved.
The yield can be improved, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus used for carrying out the method of the present invention.

FIG. 2 is an explanatory view of the operation of the present invention.

FIG. 3 is a perspective view showing a shape example of a wiring duct.

[Explanation of symbols]

 1 ... Mold device 2 ... Injection molding machine 3 ... Feed device 3a, 3b ... Clamper 4 ... Pulling device 41 ... Clamping part 42 ... Moving mechanism 42a ... Push pin 42b ... Air cylinder 42c ... Stopper 5 ... Support 5a ... Table D ... Molded product W ... Joining part d ... Micro distance F ... Tensile force

Claims (1)

[Claims] 1. An injection-molded unit molded product is removed from the mold and moved in one direction by a predetermined distance, and then the next unit molded product is injection-molded, and the tip of this molded product in the above-mentioned moving direction. Part and a step of joining the rear end of the unit molded article that has already been formed, in a method for producing a molded article of a long product by sequentially and sequentially repeating the joining part at the time of the joining. A method for producing a long molded product by continuous injection molding, characterized in that a predetermined tensile force is applied along the direction.