Failure analysis of forming production
DATE：2022/12/7 8:53:58 / READ： / SOURCE：This station
Failure analysis of forming production
(1) Unstable screw rotation① The barrel temperature fluctuates greatly;
② In the V-belt drive, the belt slips on the pulley, and the pulley or V-belt is seriously worn;
③ The barrel heating temperature control fails;
④ There are foreign matters in the raw materials in the barrel.
(2) Screw driving motor works while screw does not rotate
① The raw material temperature in the barrel is low;
② There are metal foreign matters in the barrel;
③ Transmission parts are damaged and gears are broken;
④ In the V-belt drive, the driven wheel does not work and the V-belt slips.
(3) Parts of blank tube forming die are easy to be damaged
① Low mold temperature;
② Low melt temperature;
③ The angle of the splitter cone is large and the resistance is large;
④ The design of die cavity is unreasonable, and the compression ratio is too large.
(4) Failure often occurs when the blow forming die is working
① The screws fixing the parts in the mold are loose;
② Mold moving guide sleeve and guide pillar are seriously worn;
③ The working movement of the air pressure pipe is not coordinated with the mold action, and the working position is incorrect.
(5) The billet tube extrudes too fast from the die
① The temperature of molten material is too high;
② High mold temperature;
③ Screw speed is too high.
(6) Manual for Plastic Extrusion Molding Technicians with Excessive Sagging and Elongation of Blank Tubes
① High mold temperature;
② The melt flow rate of raw material is improper and high;
③ The moving speed of the blow forming die is too slow.
(7) There is flanging phenomenon behind the extrusion die of blank tube
① The billet tube edge turns outward, indicating that the mandrel temperature is too high;
② The billet tube is rolled inward, indicating that the die temperature is too high.
(8) The die mouth of billet tube extrusion does not go straight
① The gap between the die and the mandrel is uneven, and the blank tube bends to the small side of the gap;
② The temperature of the blank tube forming die is uneven.
(9) Unstable extrusion speed of blank tube from die
① The feeding of the barrel is intermittent, and the raw materials in the hopper may be "bridged";
② The working speed of the screw is unstable;
③ The barrel heating temperature fluctuates greatly;
④ The clearance between the barrel and the screw is too large.
(10) Bubbles in blank tube
① The water content in raw materials is on the high side;
② There are volatile additives in the raw material formula;
③ The raw materials in the barrel have a long retention time and are decomposed.
(11) Blank tube has stripes
① Impurities in raw materials;
② There is stagnant material in the mold;
③ The filter screen is broken;
④ The compression ratio of die cavity is too small;
⑤ There are scratches on the die.
(12) Rough surface of blank tube
① Uneven plasticization of raw materials;
② The inner surface of the die is not smooth;
③ The temperature of molten material is too high or too low.
(13) Large forming error of blown products
① Insufficient inflation pressure;
② The air discharged from the mold is not smooth during inflation;
③ Poor cooling effect of mold;
④ The blowing air supply time is short.
(14) Bulging crack of billet tube
① The width of the clamping opening is not reasonable;
② Improve the clamping force of the blow forming die;
③ The inflation pressure is too high;
④ The blowing expansion ratio of billet tube is too large;
⑤ The length of blank tube is insufficient;
⑥ High moisture content in raw materials;
⑦ The temperature of molten material is low.
(15) Product deformation
① The cooling time of blow molding products is not enough;
② The temperature of molten billet tube is too high;
③ The production cycle of blow molding products is short.
(16) The product surface is rough and not bright
① The melting temperature of billet tube is low;
② Insufficient inflation air pressure;
③ The exhaust is not smooth in the process of inflation molding;
④ The surface of the inner cavity of the molding die is not bright;
⑤ Too much release agent is sprayed.
(17) Stripes and pits on the surface of products
① There are foreign matters in the blank tube forming die;
② Uneven temperature of molten material;
③ Insufficient inflation air pressure;
④ There are water droplets in the blowing air.
(18) Poor product strength
① Unreasonable design of product structure and shape;
② Uneven plasticization of raw materials;
③ The selection of raw material formula is unreasonable.
Author：admin