Why were Silver Streak, Bubble, and Pinhole happened?
Main causes : 1. Too much humidity. 2. Too much volatile gas. 3. The turbulence was generated upon flowing. Molding conditions, and injection machines (Solution 1) : 1. Lower the temperature of resins. 2. Increase the back pressure of screws. 3. Decrease the injecting speed. 4. Increase the compression ratio of screws. 5. Reduce the revolving frequency of screws and extend the metering time. Designs in molding products and models (Solution 2) : 1. Improve the gas venting. 2. Avoid reinforcement at right angle directions, and avoid rapid changes in material thickness. 3. Remodel the welding part between the injection nozzle and the mold gate, and check if it is tight. Materials (Solution 3) : 1. Dry up fully. 2. Use materials of less volatility. 3. Add in heat stabilizer. 4. Check if the additive itself can absorb humidity.
