Injection molding and spraying process of bumper

Abstract

The invention discloses an injection molding and spraying process of a bumper. The injection molding and spraying process comprises the following steps of preparing injection molding raw materials ofthe bumper, wherein the injection molding raw materials of the bumper are prepared from the following materials in parts by weight: 800 parts of polypropylene materials and 7 parts of polar groups; uniformly mixing the injection molding raw materials in a mixing machine; pouring the raw materials which are uniformly mixed into a charging barrel of an injection molding machine, and setting the meltindex to 18 to 28 g / 10 min; injecting the injection molding raw materials after melting into a mold cavity at high pressure, setting the temperature of the charging barrel to 215 to 235 DEG C, setting the temperature of a hot runner to 215 to 235 DEG C, and setting backpressure to 6 to 18 bar; spraying primer, colored paint and varnish to the bumper; and baking and solidifying the sprayed bumper.According to the injection molding and spraying process, a certain proportion of injection molding raw materials are used for injection molding, so that the adhesive force of oil paint sprayed on thesurface of the bumper meets the requirement, and the spraying is uniform.

Description

technical field [0001] The invention relates to the technical field of automobile manufacturing, in particular to a bumper injection molding and spraying process. Background technique [0002] Automobile bumper is an important part of automobile appearance and the main decorative part of automobile exterior. With the continuous improvement of people's requirements for automobile appearance, the coating of bumper has been paid more and more attention by various professional factories. Car bumpers are now mainly bumpers, which have certain strength, rigidity and decoration. It is integrated with the body and plays a very good decorative role, becoming an indispensable and important part of the appearance of the car. [0003] Common plastic bumpers are made of polymer material polypropylene injection molding, polypropylene has the advantages of heat resistance, corrosion resistance, etc., but because the polypropylene material is non-polar, the tension value without any treatm...

AI Technical Summary

Problems solved by technology

[0003] Common plastic bumpers are made of polymer material polypropylene injection molding, polypropylene has the advantages of heat resistance, corrosion resistance, etc., but because the polypropylene material is non-polar, the tension value without any treatment is 26- 28dyn / cm, so the surface tension value of the injection molded plastic bumper is small. When spraying paint, the paint cannot evenly adhere to the surface of the substrate, which affects the appearance quality and paint performance of spraying

In order to solve the problem of small tension value, a flame gun head is generally installed on a fully automatic robot, and a 1000°C flame is sprayed on the surface of the bumper to instantly change the surface polarity, so that the surface tension of the bumper can be greater than 40dyn / cm, so as to meet the requirements of spray painting. Adhesion requirements, but the paint is flammable and explosive, and there is a great risk of flame treatment in the spray booth, and the bumper after flame treatment must be sprayed within 4 hours. If the time exceeds, the surface tension value Will return to the original state, so there is an urgent need for a safe and reliable bumper spray flame-free treatment technology