JP4322410B2 - Marble molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding method for imparting a marble pattern to a resin molded product such as a vehicle fender, and a molded product obtained by the molding method.
[0002]
[Prior art]
When changing the color of a molded product using an injection molding machine, first change the color of the molded product from the hopper into the injection molding machine, and then the resin of the previous color stuck to the screw etc. (Residual resin) is discharged as a purge material, and then the subsequent color resin is put into the injection molding machine, and the color change material remaining in the injection molding machine is discharged as a purge material by the subsequent color resin and injected. Injection molding is performed after the resin in the molding machine is completely switched to a resin of a later color.
[0003]
The molding method described above is for molding a single color product, but various molding methods for imparting a marble pattern to the product during molding have been proposed.
For example, in Japanese Patent Laid-Open No. 48-42060, a plurality of resins having different colors are filled in a molding machine in a semi-molten state and completely melted while passing through a gap between tobeads provided in the molding machine. There has been proposed a method of injection molding a molded article having a pattern.
Japanese Laid-Open Patent Publication No. 57-72836 proposes a method in which a tobead made of spiral plate blades is provided in a nozzle, and a plurality of resins having different colors melted by the tobead are mixed and injection molded. .
Japanese Patent Application Laid-Open No. 2-265722 proposes a method for producing a marble molded product in which a hopper and a screw corresponding thereto are provided at the upstream and downstream portions of the heating cylinder of the injection molding machine, respectively, to suppress excessive kneading. ing.
Japanese Patent Application Laid-Open No. 5-71373 proposes a method of forming a marble pattern which is a constant pattern and does not become a blurry pattern by dividing the toad into an inner tobead and an outer tobead.
Japanese Patent Application Laid-Open No. 9-169043 discloses a rod having a second resin path inserted into a first resin path formed in a heating cylinder, and injects the first resin and the second resin while kneading. A marble molding method has been proposed.
[0004]
[Problems to be solved by the invention]
In each of the above-described prior arts, a special device is devised in order to obtain the same marble pattern as much as possible. However, since the marble pattern is different for each product, the interestingness and the product value are increased, and the conventional technique does not match the demand for the marble pattern with demand.
[0005]
Also, in the past, an injection molding machine dedicated to marble patterns is assumed, and the idea is to form a marble pattern using a single color molding machine, and to make effective use of purge materials when changing colors. Is not shown at all.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a marble molding method using an injection molding machine that injects a molten resin into a mold, and sequentially sends a plurality of resin materials having different colors sequentially to a heating cylinder, A plurality of resin materials having different colors, which are melted by a heating cylinder, are injected into a mold while being kneaded by rotation of a screw. By setting it as the said structure, marble molding can be performed using the general injection molding machine which does not elaborate special idea.
[0007]
In addition, the main molding was performed by using resin color change. By doing in this way, the molded product of a marble pattern can be obtained using a single color molding line and without using a useless material. That is, conventionally, a purge process is required for color change, but the purge process is eliminated and molding efficiency (time and material) is improved.
[0008]
In addition, the product obtained by this molding method is a product that is unique and enhances the willingness to purchase because the ratio of the resin of the previous color and the resin of the subsequent color changes continuously, so there are not two identical patterns. be able to.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall view of a molding apparatus used in a molding method according to the present invention. The molding apparatus includes a mold apparatus 1 and an injection molding machine 2. The mold apparatus 1 includes a fixed mold 11 and a movable mold 12. The fixed mold 11 is fixed to a support plate 13, and the movable mold 12 is fixed to a movable plate 15 that moves forward and backward relative to the support plate 13 by driving a cylinder unit 14.
[0011]
By driving the cylinder unit 14 and aligning the movable mold 12 with the fixed mold 11, a cavity 16 (see FIG. 2) is formed between the molds 11 and 12, and a runner 17 connected to the cavity 16 is formed in the fixed mold 11. Is formed.
[0012]
Further, the injection molding machine 2 can be moved forward and backward with respect to the fixed mold 11 by a cylinder unit 21. In this injection molding machine 2, the tip of a heating cylinder 23 having a heater 22 on the outer periphery is used as an injection nozzle 24, and a screw 25 is disposed in the heating cylinder 23, and the screw 25 is fixed on the heating cylinder 23. 26 and a gear train 27 are allowed to rotate.
[0013]
Thus, when the raw material resin is introduced into the heating cylinder 23 from the hopper 28 provided on the upper surface of the heating cylinder 23, the raw material resin is sent forward (leftward in the figure) by the rotation of the screw 25, It melts and is finally injected from the tip of the nozzle 24.
[0014]
In order to mold a marble pattern product using the injection molding machine 2 described above, first, as shown in FIG. 2A, a single color product is injection molded using the resin P1 of the previous color.
[0015]
When the molding of this single color (P1) is completed, conventionally, the color changing material is introduced from the hopper 28 to remove the resin of the previous color adhering to the screw 25 and the like. The color resin is injected as a purge material and discarded. In the present invention, as shown in FIG. 2 (b), the resin P2 of the subsequent color is replaced with the resin P2 of the previous color. The molten resin is injected into the cavity 16 while being put into the hopper 28 and kneading the resin P1 of the previous color and the resin P2 of the subsequent color by the screw 25 in the heating cylinder 23.
[0016]
FIG. 3 shows a front fender W of a motorcycle as an example of a product obtained by the above molding method.
As can be seen from this figure, the front fender W has a marbled pattern in which the resin P1 of the previous color and the resin P2 of the subsequent color are mixed at random.
[0017]
In the embodiment, an example using two types of resins was shown, but the number of resins to be kneaded may be three or more, and the front fender of a motorcycle is shown as a product. However, the present invention is not limited to this, and may be interior parts such as a battery box in addition to external parts such as a front fender and a body cover, and may be a member applied to other than a vehicle.
[0018]
【The invention's effect】
As described above, according to the present invention, a plurality of resin materials having different colors are continuously fed back and forth into an injection molding machine, and a plurality of color resins are kneaded as they are by rotating a screw, and then the nozzles are fed into the mold. Therefore, marble molding can be performed using a general molding machine for a single color without any special contrivance for the injection molding machine.
[0019]
Also, using color change in a single color line, the previous color resin is fed into the molding machine following the previous color resin, and the previous color resin and the subsequent color resin are kneaded by rotating the screw as it is. However, if it is injected from the nozzle into the mold, the resin that has been discarded as the purge material can be used. Conventionally, the purge process is a process in which a product is not molded. However, according to the present invention, the purge process is eliminated and the molding efficiency is improved accordingly.
[0020]
Furthermore, in the conventional molding method, a uniform marble pattern is created as much as possible, but the marble pattern formed in the molded product according to the present invention has a resin ratio of the previous color and the subsequent color. Since it changes continuously, a pattern rich in change can be obtained, and since there are no two products with the same pattern, differentiation from other people's car bodies is remarkable and the willingness to purchase can be enhanced.
[Brief description of the drawings]
FIG. 1 is an overall view of a molding apparatus used in a molding method according to the present invention. FIG. 2 (a) is a diagram illustrating a state in which a resin of the previous color is injection molded, and FIG. FIG. 3 illustrates an example of a marble molded product obtained by the method of the present invention. FIG. 1 shows a mold apparatus, 2 ... Injection molding machine, 11 ... Fixed mold, 12 ... Movable mold, 13 ... Support plate, 14 ... Cylinder unit, 15 ... Movable plate,
16 ... cavity, 17 ... runner, 21 ... cylinder unit, 22 ... heater, 23 ... heating cylinder, 24 ... injection nozzle, 25 ... screw, 26 ... motor 27 ... Gear train, 28 ... Hopper, P1 ... Previous color resin, P2 ... Previous color resin, W ... Molded product.

Claims (1)

 This is a marble molding method using an injection molding machine that injects molten resin into a mold. This marble molding method uses color change in a single color line and changes the color of the resin supplied into the mold. In the state where the resin of the previous color remains in the heating cylinder, the resin of the subsequent color is put into the hopper of the molding machine, and the resin of the previous color and the rear are screwed in the heating cylinder by the screw. A marble molding method characterized by injecting a resin of any color into a mold while kneading.

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