Defects and solutions of transparent plastic parts

2021-03-23 15:20:55 admin

Defects and solutions of transparent plastic parts




The shortcomings are as follows:


 (1) Silver streak: Affected by the anisotropy of internal stress during the filling and condensation process, the stress generated in the vertical direction causes the resin to undergo flow-up orientation, and the refractive index is different from the non-flow orientation to produce flashing silk patterns. After its expansion, it may cause cracks in the product. In addition to paying attention to the injection molding process and injection molding mold (see the table, the product is best to be annealed. For example, the pc material can be heated to above 160 ℃ for 3 to 5 minutes, and then cooled naturally.


   (2) Bubbles: The water vapor and other gases in the resin cannot be discharged (during the condensation process of the injection mold), or due to insufficient mold filling, the condensation surface condenses too quickly to form a "vacuum bubble". The ways to overcome it are shown in the table.


(3) Poor surface gloss: Mainly due to the roughness of the injection mold, on the other hand, premature condensation prevents the resin from copying the state of the mold surface of the injection mold, all of which make the surface produce small irregularities and make the product lose luster. The ways to overcome it are shown in the table.


(4) Shock lines: refers to the dense ripples formed from the straight gate as the center. The reason is that the melt viscosity is too large, and the front end material has condensed in the cavity, and then the material breaks through the condensation surface, causing the surface to appear shock lines . The ways to overcome it are shown in the table.


   (5) Whitening. Haze: Mainly caused by dust falling into the raw material in the air or the raw material has too much water content. The ways to overcome it are shown in the table.


   (six) white smoke. Black spots: mainly due to the decomposition or deterioration of the resin in the barrel due to partial overheating of the plastic in the barrel. The ways to overcome it are shown in the table. In order to clearly explain the measures taken to overcome these deficiencies, a table is listed for your reference.


Table 4: Defects of transparent products and overcoming methods: overcoming method defects, silver pattern, bubble, surface gloss difference, shock pattern, whitening, haze, white smoke, black spots, resin raw materials have impurities or pollution, remove impurities, pollution remove impurities, pollution remove impurities, pollution Resin raw materials should be dried and dried sufficiently. To be fully dried. To fully melt the material. Reduce temperature, control precision to ensure plasticization, then decrease and increase, especially the nozzle is reduced, and the control accuracy is reduced as much as possible. Injection pressure is increased, increased, increased, increased, adjusted properly, and not deteriorated. Increase in injection speed, increase in injection time, increase in injection time, increase in pressure, decrease in production cycle, decrease in material residence time in the barrel, back pressure adjustment, appropriate increase in screw speed, decrease in pouring system, reasonable (size and layout), wall thickness part and gate setting layout is reasonable and reasonable ( Size and layout) reasonable, as short and thick as possible, adjust the mold temperature appropriately, increase slightly, increase, increase the cooling time, increase the position of the exhaust vent of the injection mold mold, and the position of the vent hole. Improve the vent hole for the cooling well Enough position to the nozzle, runner, gate can not be blocked, the material is smooth, the material is not blocked, the material is not blocked, the injection volume is increased