博文

目前显示的是 七月, 2019的博文

Analysis of Common Defects in Plastic Products-Size Change

Basic Reasons: From the perspective of plastics, the reasons for the size change are as follows: The change of pressure distribution in U-shaped cavity will cause the change of size. For crystalline plastics, the change of crystallinity due to the change of cooling rate will cause the change of size. After-treatment of U products, changes in ambient temperature and humidity can also cause size changes. Next, the change of pressure distribution in the cavity and the size change are analyzed and discussed. The causes of defects will vary with the size changes. First, defect phenomenon: the overall product size is too small. Cause analysis: the plastic pressure in the cavity is too low. Solution: Increase the feeding pressure to meet the cavity pressure required by qualified products. 2. Defects: Overall product size is too large Cause analysis: the plastic pressure in the cavity is too high. Solution: Reduce the feeding pressure to achieve the cavity pressure required by qualified prod…

FR4 classification

The surface color of FR-4 epoxy glass cloth laminate is as follows: Yellow FR-4, white FR-4, black FR-4, blue FR-4, etc. FR-4 is the base plate used by PCB, and it is a kind of sheet metal. According to the different reinforcing materials, sheets are mainly classified into the following four types: 1) FR-4: Glass Cloth Substrate 2) FR-1, FR-2, etc.: Paper Substrate 3) CEM Series: Composite Substrate 4) FR-4 of special material substrates (ceramics, metal substrates, etc.) is a plate-like laminated product made of epoxy phenolic resin and other materials impregnated with special electronic cloth by hot pressing at high temperature and pressure. Features: It has high mechanical and dielectric properties, good heat and moisture resistance and good machinability. Usage: Used as insulating structural parts in motor and electrical equipment, including various types of switch FPC reinforcing electrical insulation carbon film printed circuit board, computer drilling cushion die fixture (PCB …

Factors that are more susceptible to influence in the production of plastic products

Fillers, also known as fillers and fillers, are solid substances added to the matrix of polymer materials to reduce costs and/or improve some properties of products. The main factors to be considered when choosing fillers are as follows: 1. Low Price The price of filler has a great influence on the cost of plastics. The proportion of polyvinyl chloride plastics with fillers is 2-3 times that without fillers. Therefore, the proportion of polyvinyl chloride plastics with fillers increases rapidly with the increase of the amount of fillers. Therefore, the cost based on weight is not as accurate as that based on volume. In application, the volume cost must be considered. The small proportion of filler is more advantageous to the volume cost. 2. Oil Absorption That is, the ability of fillers to absorb plasticizers. It depends on the fineness of filler and the variety of filler and plasticizer. The cost of plastics increases with the increase of oil absorption. 3. Electrical Performance Th…