JPS6228212A - Removing of curing in curled member - Google Patents

Abstract

PURPOSE:To remove curling from a curled member by a method wherein fine particles are blasted against the curled member from both its sides under the condition that the blasting pressure against the concave side of curling is made higher than that against the convex side. CONSTITUTION:Fine particles 8 are blasted from nozzles 6 and 7 arranged above and below the molded part under high pressure against a molded part 1 carried with the concave side of curling directing upwards. The blasting pressure of the nozzle 6 which is arranged above the molded part and faces to the concave side of curling is kept to be higher than that of the nozzle 7 which is arranged below the molded part. The molded part 1, both the top surface and the underside of which are shot by the fine particles, is sent to the following process with pinch rollers 5 in the state of being flat after the curling being removed by the above-mentioned blasting treatment. Because a curling removing device is run at normal temperature, spring-back due to heat does not develop on the molded part 1. Further, when the amount of curling of the molded part 1 is different due to the change of molding, the curling is removed by properly setting the pressure of the nozzles 6, 7 above and below the molded part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for removing curls from a curled member 1, such as a resin molded product.

[Conventional technology]

Conventionally, resin molded products produced by press molding, etc., especially molded products made of notebook material with many drawn parts simultaneously, are prone to curling, which can cause problems in the filling part of the post-process. Ta. Methods for removing this curl include a method in which the mold itself has a curvature opposite to that of the curl, or a method in which the curl is corrected using a weight while applying heat after molding.

[Problem that the invention seeks to solve]

However, the method to give the mold a curvature is 2. How much curvature should be made is the first trial! Due to repeated mistakes, it takes a long time to complete the mold, and machining is difficult, resulting in high costs. In addition, the method of applying heat to correct the
Heat causes spring hack in the molded product.

The problem was that the molding depth tends to be shallow.

The present invention aims to solve such conventional problems,
To provide a method capable of removing curls from a molded product without causing springback in the molded product and without requiring an expensive mold.

[Means for solving problems]

The method for removing curls of the present invention involves spraying fine particles onto both sides of a member having curls, such as a molded product.

The blowing pressure at that time is maintained higher on the concave side of the curl than on the convex side.

[Effect]

The reason why curls are removed by the above method is not clear, but it is thought to be of the first order. That is, when fine particles are sprayed onto a molded article, plastic deformation naturally occurs in the portion of the molded article where the fine particles collide. Since this deformation is larger on the concave side than on the convex side, it is thought that the surface on the concave side is pushed wider than that on the convex side, and as a result, the curl is removed.

〔Example〕

The following two inventions will be explained in more detail using embodiments shown in the drawings.

FIGS. 3 and 4 are a top view and a side view showing an example of a molded article from which curls are removed by the method of the present invention. Molded product 1
is a sheet material in which a large number of molded parts (indentations) 2 are formed, and the material is a single-layer or multi-layer thermoplastic resin sheet such as polystyrene, polyvinyl chloride, polypropylene, polyethylene, polyester, polyamide, etc. combination is used. This molded product was molded using conventional methods such as press molding, vacuum molding, or pressure molding, but due to molding distortion, the entire molded product curled downward, as shown in Figure 4. . That is, the upper surface 3 is on the concave side, and the lower surface 4 is on the convex side. Such curled molded products tend to cause trouble when the recesses 2 are filled with contents and sealed in the next step.

FIG. 1' is a side view showing a schematic structure of a curl removal device used for removing curls from the molded product 1 according to the method of the present invention, and FIG. 2 is a front view thereof. The curl removing device comprises pinch rollers 5 arranged at appropriate intervals, and an upper nozzle 6 and a lower nozzle 7 that spray fine particles 8 with high pressure fluid, such as high pressure air. The pinch rollers 5 are used to pinch and transfer both ends of the molded product 1 without the recess 2, and the surface of the pinch roller 5 is wrapped with a flexible material such as silicone rubber, and the pinch roller 5 is driven by an external motor or the like.

The upper nozzle 6 and the lower nozzle 7 are arranged in the gap between the pinch rollers 5 and spray fine particles onto the upper and lower surfaces of the molded product 1 that is conveyed by the pinch rollers 5. As the fine particles to be sprayed, beads or powder of glass, styrene, walnut, etc. can be used. The particle size of the fine particles is preferably about 0.05 to 0.30 mm.

A plurality of sets of the upper nozzle 6 and the lower nozzle 7 may be installed in the conveyance direction of the molded product 1.

Next, a method for removing curls using the above device will be explained.

The curled molded product 1 is conveyed rightward in FIG. 1 by pinch rollers 5. At this time, the molded product 1 is transported with the curled concave side facing upward. Fine particles 8 are sprayed at high pressure from upper and lower nozzles 6.7 onto the molded product 1 being transported.

The blowing pressure at this time is maintained so that the upper nozzle 6 facing the curl concave side is higher than the lower nozzle 7.

The pressure of the upper nozzle 6 is usually 3 to 6 kg/cj, and the pressure of the lower nozzle 7
is maintained at 0.5-3 kg/c+d. The molded product 1 whose upper and lower surfaces have been hit with fine particles is sent to the next process by a pinch roller 5, but this process removes curls and makes it flat as shown in FIG. Since the above-mentioned curl removal device is operated at room temperature, spring banks will not be generated in the molded product 1 due to heat. In addition, if the curl amount of the molded product 1 differs depending on the molding method, the pressure of the upper and lower nozzles 6 and 7 should be adjusted appropriately.

Curls can be easily removed.

The above-mentioned curl removal device is configured to transport the molded product and spray fine particles onto the upper and lower surfaces of the molded product, but it is also possible to keep the molded product stationary and move the upper and lower nozzles that spray the fine particles along the molded product. Good too.

Next, examples will be specifically described using numerical values.

Example molded product 1 was made of polystyrene with a thickness of 500μ, and
Press molding was performed at ~120°C to form a plurality of molded parts 2. The molded product 1 was conveyed while being pinched between pinch rollers 5 driven by an external motor. The molded product 1 was prepared by spraying glass beads 8 having a particle size of about 150 μm onto the surface of the molded product 1 using nozzles 6.7 installed above and below the gap between the pinch rollers 5. Upper nozzle pressure 3.5k
g/cJ, and the pressure at the lower nozzle is 2.5 kg/cd.

The rotational speed of the pinch roller 5 was controlled so that the time for spraying the glass beads 8 onto the molded product 1 was 1 second. The curls as shown in FIG. 4 were removed from the obtained product, and a flat product as shown in FIG. 5 was obtained. In addition, since no heat was applied to the product, a good product was obtained without causing spring banks.

Note that the above explanation is based on the case where the present invention is applied to a molded product, but the present invention is not limited to molded products, but can also be applied to other members having curls.

〔Effect of the invention〕

As explained above, according to the method of the present invention, fine particles are sprayed on both sides of a member that has been held together.

Moreover, the curls can be removed by simply adjusting the blowing pressure so that the concave side of the curl is higher than the convex side, and there is no need for heating at that time, so there is no springback in the product. It has the excellent advantage of being able to obtain good products without such problems.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of an apparatus used to carry out the method of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a top view showing an example of a molded article from which curls are removed by the method of the present invention. FIG. 4 is a side view thereof, and FIG. 5 is a side view of the molded product after curl removal. 1-Molded product 2-・Molded part 3-Top surface 4-・Bottom surface 5
- Pinch roller - 6 - Upper nozzle 7 - Lower nozzle 8 - Fine particles Patent applicant Roku Konishi Photo Industry Co., Ltd. Dai Nippon Printing Co., Ltd. Agent Patent attorney Kyo Matsu Miga 1 Figure 2 Figure 3

Claims (1)

[Claims] A method for removing curls from a curled member, characterized by spraying fine particles onto the curled member from both sides, and maintaining the spraying pressure higher on the concave side of the curl than on the convex side.