JPS6211618A - Plastic molding and processing device - Google Patents

Abstract

PURPOSE:To save lots of process, precision molds, conditions of molding requiring experience and others, by passing the softened synthetic resin extruded from the extruder in the form of a specific shaped section through the upper face of molding roller while the resin remains sufficiently plastic. CONSTITUTION:An extruder B to heat and soften synthetic resin materials and extrude the material (a) is provided on the side of molding and processing device A, and the specific type die 12 installed at the mouth of extruder extrudes out the required amount of resin material fit for the product continuously in the shape of strip or line. The extruded material (a) is guided onto the face of molding roller 1, opposite side to water, which rotates at the speed same as the travelling speed of resin material, and is molded by the face of molding roller 1. The molded intermediate product travelling the roller 1 rotating, is cut with the cutter 10 working once per rotation of roller, dropped and dipped into the underneath cooling tank 9 to be cooled down into a stabilized form.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a molding device for making mudguards for bicycles, children's cars, etc., and other general plastic products having arbitrary curved shapes, using thermoplastic synthetic resin as a raw material. .

<Conventional Technology> Conventionally, to form mudguards for bicycles, children's cars, etc., and base metal products thereof, thin metal sheets have been punched in advance using a press to a size roughly commensurate with the finished product.

This is then drawn into a drawing die using another press, which gradually approaches the shape of the finished product in several stages depending on the degree of deformation (depth of drawing, degree of bending), or drawn with rolls. I was processing it.

Then, it was finished by polishing with a separate cloth, plating, or painting.

Therefore, the above method utilizes the plasticity of a thin metal sheet to form it, but there are many steps required to complete it, and the drawing depth and shape vary, requiring a burning process. In addition, there is a drawback that the product cannot be completed without going through a bending process.Furthermore, since the base metal is usually an easily available iron plate, it is necessary to apply anti-corrosion treatment.

Therefore, since such press-molded products are expensive due to labor costs and mold fees, they are often molded using synthetic resin, but when using synthetic resin, the synthetic resin raw material is heated and softened before being molded. By injecting the product into a molding die under high pressure using an extruder, a product having a shape that imitates the mold is molded all at once.

Therefore, with synthetic resin, the number of steps is fewer than when press-forming metal, there is no need for anti-corrosion treatment such as plating or painting, and productivity is much better than when press-forming is used. In the case of synthetic resin molding, the manufacturing cost of the molding mold is high, and in addition, skill is required to maintain the mold and maintain the molding conditions.

<Problems to be Solved by the Invention> The present invention addresses the drawbacks of the conventional processing methods described above, and provides a molding device that does not require multiple steps, precision molds, or molding conditions that require skill. The purpose is to

Means for Solving the Problems> The present invention provides a material extrusion device that extrudes thermoplastic synthetic resin in a softened state, and a forming roll that moves the mold surface at a synchronous speed in accordance with the extrusion speed of the material. It consists of a device for cutting the continuously molded product, and a cooling device for rapidly quenching the product.

<Operation> By passing the softened synthetic resin extruded through a cross section of a certain shape by an extrusion device over the upper surface of a forming roll with sufficient plasticity, the shape of the material is determined according to the mold surface of the forming roll. The product is cut to the required length and quickly cooled to stabilize the product without deformation.

<Example> Hereinafter, the apparatus of the present invention will be explained in detail with reference to an example shown in the drawings.

First, the forming apparatus A shown in FIGS. 1 and 2 has a forming roll 1 having a predetermined cross-sectional shape supported horizontally by a pongee 3 on a machine frame 2, and a pulley fitted to one end of the shaft 3. 4 and a pulley at the end of the output shaft of the electric motor 11, and when the electric motor 11 is driven, the forming roll 1 is rotated at a constant speed through the belt, at a speed corresponding to the shape of the product. A cutting device 10 is supported on the concentric axis of the forming roll 1 and facing the outer peripheral surface of the forming roll 1, and the cutting device is synchronously rotated along the outer periphery of the forming roll 1 only during the cutting operation. It moves at a high speed and returns to the initial position at the same time as the cutting is completed, so that the cutting is repeated within a predetermined range on the circumference of the forming roll 1.

Furthermore, the forming roll 1 has its substantially lower half submerged in a cold water tank 9 placed on the side surface of the machine frame 2, and the water in the cold water tank 9 is drained by a cooler (not shown). It is made to circulate continuously.

Then, on the side of the molding processing apparatus A configured as described above, an extrusion apparatus B for heating and softening the synthetic resin raw material and extruding the material a is installed oppositely, and the extrusion apparatus B is attached to the extrusion opening in a predetermined shape. The amount required for each product is continuously extruded from the goose 12 into a band or line, and the extruded material a is molded by rotating at a speed synchronized with the feeding speed of the material a. On the drainage side of the roll 1, it is guided onto the mold surface of the forming roll 1 and is formed by the mold surface of the forming roll 1. The shape of the mold surface of the forming roll 1 generally differs depending on the shape of each product, but as an example, as shown in FIGS. Product 51 by forming roll 1 with II
In the forming roll 1 having a trapezoidal convex portion 12 in cross-section, a product 5□ is formed. Furthermore, as shown in FIG. 4, the side surfaces of the finished products are curved to follow the outer periphery of the forming roll 1. The intermediate product formed in this way further moves together with the forming roll 1, is cut by the operation of the cutting device 10 that operates at every predetermined rotation angle of the forming roll 1, and falls into a cold water tank 9 provided at the bottom. It is soaked and cooled to stabilize its shape.

In the above example, the forming rolls are configured so that they can be freely replaced with each other depending on the desired product.Moreover, although the example shown in the figure shows an example of forming a circular product, this pond forming roll can be used in a spiral manner. It is also easy to form a spiral product by replacing it with a shaped one.

Furthermore, although one example of the molding apparatus has been shown above, the molding apparatus A'' shown in FIG.
is pivotally mounted, and movable molds 1', 1', . . . each having an arbitrary curved surface shape of a semicircular shape are arranged at equal intervals on a chain band 14 stretched across the sprocket wheels 13, 13.

Then, on the side of the molding device A°, an extrusion device B is installed oppositely as described above, and the material a extruded from the die 12 of the extrusion device B is supplied onto the movable molds 1', 1', . . . It may be configured to do so. In this case, similarly to the above, the material in a softened state on the movable die 1 is molded into a predetermined cross-sectional shape of the movable die moving in the direction of the arrow, and is placed in the middle of the circulation path of the chain band 14 during the cutting operation. A cutting device that operates intermittently and moves at a speed synchronized with the chain belt 14 and returns at the same time as cutting is completed is provided, and the product is separated from the supply side and dropped into the cold water tank 9 located below and immersed. This results in a stable product.

In addition, in the above two embodiments, the molding of the product is performed using die 1.
Since the material extruded from 2 is in a softened state, it is formed into a predetermined cross-sectional shape by the forming roll 1 and the movable dies 1', 1'. Therefore, if a certain shape is required on the outside of the product, or if it is difficult for the product to follow the mold surface of the mold roll itself due to the type of material, an auxiliary mold roll can be circumscribed on the outside of the mold roll. Although a cold water tank was used as a cooling means for the product, any other cooling means may be used, such as spraying cold water as a shower or blowing cold air.By spraying such cold water or cold air, It does not require a large water tank, and especially when using a chain belt circulation system as in the latter embodiment, it is effective without taking up much space.

<Effects of the Invention> The molding apparatus of the present invention, as described above, breaks the conventional fixed concept that molding is possible only by enclosing the material in an airtight mold, and molds the material while it is in a softened state. Since the molding is performed on the mold surface of the molding roll, there is no need for elaborate and complicated plastic molding molds, and the number of molds can be greatly reduced.

In addition, it can be continuously molded, has good workability, and is suitable for mass production. Moreover, since the configuration is simple, maintenance and management are significantly easier than previous ones.

Furthermore, unlike the conventional method of drawing metal using a press, such as mudguards for bicycles, children's errands, and their base metal products, there are fewer steps and production costs are lower, and the forming process is not limited to the mudguards mentioned above, but can also be applied to other arbitrary cross sections. It has many advantages such as it is easy to form products with various bent shapes, and it is possible to obtain various products with arbitrary cross-sectional shapes and different curved shapes using only easy-to-manufacture forming rolls. It has a good effect.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of the molding processing apparatus of the present invention, Fig. 2 is a sectional view taken along line XX in Fig. 1, and Fig. 3 (1) and (2) are cross sections of different forming rolls. FIG. 4 is a partially enlarged sectional view showing the shape, and FIG. 5 is a partially cutaway front view showing an example of a pond device. DESCRIPTION OF SYMBOLS 1... Forming roll, 1゛... Mobile type 9... Cold water tank, 10... Cutting device 14... Chain belt

Claims (1)

[Claims] 1. A rotating molding roll, a material extrusion device that supplies a softened resin material toward the mold surface of the molding roll, and a cutting device disposed oppositely in the middle of the path of the molded product; and a cooling device for cooling the molded product, and the plastic material extruded from the die of the extrusion device is molded by the molding roll while uncured onto the surface of the molding roll, and then cut and immediately cooled. Characteristic plastic molding equipment. 2. The plastic molding apparatus according to claim 1, characterized in that the plastic molding apparatus comprises a movable mold in which a plurality of molding rolls each having a predetermined shape are arranged in rows on an endless band. 3. The plastic molding apparatus according to claim 1, characterized in that a cold water tank is used as the cooling device. 4. The plastic molding apparatus according to claim 1, characterized in that a device for blowing cold water or cold air is used as the cooling device.