(1) Plastic injection molding machine capacity Small
If the quality of the products exceeds the actual maximum injection quality of the injection molding machine, the feeding amount is beyond the means; If the product quality is approaching the actual injection quality of the injection molding machine, the plastic is not enough, the heating time is insufficient in the barrel, and the suitable melt can not be provided to the mould. Need to replace the capacity of large injection molding machine.
(2) The thermometer shows that the temperature is not true, the high is low, causing the material temperature too low
The heating failure is caused by temperature control device (such as thermocouple and its wiring or temperature difference mv meter), or the heating coil away from the temperature point aging or burned down. The replacement should be repaired promptly.
(3) The diameter of the nozzle hole is too large or too small
Too small, because the circulation diameter is small, the ratio of the material increase, easy cooling, plugging the feeding passage or consumption of injection pressure; too large, the circulation cross-section is large, the plastic inlet unit area pressure is low, the formation of a small injection force.
If the ABS does not obtain large shear heat, it can not reduce the viscosity, resulting in the difficulty of filling mold. The nozzle and the mainstream channel entrance is bad, often occurs in the mold spill, mold filling discontent phenomenon. The nozzle itself flow resistance is very large or foreign body, plastic carbonization sediment, such as plugging; the nozzle or the main entrance of the spherical surface damage, deformation, affect the good cooperation with each other; the mechanical failure or deviation of the injection seat causes the nozzle to have a tilted displacement or axial compression surface from the main shaft. Nozzle ball diameter is larger than the main entrance ball diameter, due to the edge of the gap, in the overflow squeeze gradually increasing the nozzle axial push force will cause a product note dissatisfaction.
(4) Plugging the feeding passage of plastic melt block
Because the plastic in the hopper dryer local melting agglomeration, barrel feeding section temperature is too high, plastic grade choice improper, plastic contains too many lubricants will make plastics into the feeding mouth shrink position or screw screw end of the deep groove melting prematurely, causes the grain material and the melt bonding mutually to form "The bridge", the blockage passage or the pack-live screw, along with the screw rotation makes the circumference slip, cannot move forward, causes the material interruption or the irregular fluctuation. This situation can only be solved after digging through the passage and excluding the material block.
(5) Nozzle Cold feeding Mould
Injection molding machines are usually fitted with straight-through nozzles due to pressure loss, but if the front end of the barrel and the nozzle temperature is too high, or in the high-pressure state of the drum front-end storage too much, produce "salivation", so that plastic not started injection and mold open in case, Italy to enter the mainstream entrance and the template in the cooling effect of hardening, so as to hinder the melt smoothly into the cavity. At this time, should reduce the barrel front and nozzle temperature and reduce the storage volume of the barrel, reduce the back pressure to avoid the barrel front melt density too large.
(6) The injection cycle is too short
Due to the short period, the material temperature can also cause the shortage of material, especially when the voltage fluctuation is large. To adjust the cycle according to the supply voltage. Adjust the general do not consider injection and retention time, mainly consider adjusting from the pressure to the screw back of the period of time, neither affect mold filling conditions, but also can lengthen or shorten the material particles in the preheating time of the barrel.
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