Formation of trapped air is compressed andĢ. Surrounded by molten plastic mould in the airĪnd air trapped in it. On the blow molding machine, it also have the heater to heating PET preform.Ģ. Plastic injection cylinders in heated for too long. In the previous production operation with an incorrect machine clearance procedures therefore the plastic cooked in cylinder.ħ. Check the hopper is always filled with plastic to a stable heightĦ. Ensure that the air not incident with tank and plastic.Ģ. Check a screw surface speeds are correct.ġ. Put plastic factory for at least six hours before injection.Ĭhanging color of plastic (from yellow to black), usually appeared in runner tails or compressed areas.Ģ. Workshop of plastic into the warm air moisture condenses on the cold plastic. Plastic flow in the mold of uneven air trapped in it. Inserted in mold venting or expand existing vent depth.Ģ. On the injection molding machine remains stable bedding. Reduce the speed of the screw, and reduce cable volume. Reduced melt temperature, particularly the latter. Trapped in the injection of air in the cylinder. If melt temperature contains gases (volatile compounds), then packing disappears in the injection molded parts also contain air bubbles.ġ. Top Bubbles ( Or Steelyard balance : stranded gas) Hopper or filling machines to be removed and cleaned thoroughly.ĭouble check the signs of impurities when recycle material being separated.Ĭheck for strict implementation of recycling programs. Reduced the mixture proportion of recycle materials with the new plastic materials. If possible, design the product in order to improve the weak sections. Injection molded parts is not sufficient for a particular plastic. Injection molded parts annealed, if nylon plastic products, which dipped in warm water. The pressure of injection molded parts without proper release or not be processed. Use full-round runners and increase the size of runner and gate to provide acceptable mold filling phase shear rate. Runner and the gate are too small, so the mold filling produced excessive shear rate. Limit the speed of cooling flows through the mold. On the automatic injection molding machine remains stable bedding. In all regions to reduce injection cylinder temperature. The breakdown of the molecular structure of plastics caused by degradation in cylinder. Reduce the speed of the screw or adjust the screw speed to get the correct surface speed Increase temperature in tank and injection mouth. Injection parts split or easily broken in the process of molding. Poor plastic flow characteristics caused by Insufficient lubrication of plastic.Īdda certain amount of external lubricant (such as 0. Due to the lack of room cleaning or plastic dry cause plastic blended with burnt particles.ĭry cleaning and reuse of some materials.Ĥ. Strict inspection after the separation of impurities in materials.ģ. Excessive heating of the back using the previous materials. PET or other heat-sensitive plastic appear impurities.Ĭheck the source of impurities, especially with PET manufacturing and conveying plastic pipe part.Ģ. The hot runner mold aggregates tube completely remove and clean.ġ. Wall injection molded too thin, so that plastic flow is not sufficient to pass through, so it causes no degradation.Ĭheck the correctness and consistency of wall thickness, if necessary, will be modified. Mold and nozzle should be removed and thoroughly cleaned.ģ. Use a correct type of screw design in the process of plastic. Use minimum back pressure and the correct use of the screw surface speedĦ. Using the incorrect screw surface speed and back pressure, causing the molten plastic over cut. Reduce the cycle time to increase plastic that is passed by the cylinder device.ĥ. Check the flow rate if its sufficient for cooling the hopper locking device, adjust the flow rate if necessary.Ģ. Reduce fire zone melt temperature in a feed tank. Plastic enters the mould cavity too fast causing excessive shear polymer.ġ. Use open or direct type nozzle to replace opening and closing nozzle.Ĥ. Check whether the nozzle is located correctly in injection cylinder.ģ. cylinder and screw should be removed and thoroughly clean the surfaces in contact with the polymer melt.Ģ. Plastic material traps in the cylinder device's deadĪrea or stagnant area, causing it to stay too long in the highġ. Use cleaning compounds or high molecular weight PMMA material to clean the injection cylinder unit.Ģ. The last production of degradable plastics materials in theĬylinder, screw, valve adapter maybe curing inside the aggregate hot Spots and stripes still visible even the molding parts have the correct color.ġ. 3) Bubbles (Or Steelyard balance : stranded gas)ĥ) Plastic injection molding machine of mucosaġ0) Injection molded parts does not shrinkġ7) Injection molded parts size differences
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