Plastic drain board belong fecal plastic products, plastic drain board will be crisp manure, a large part is due to the stress caused, of course, cause brittle plastic drain dung board for many reasons, Xiao Bian main points are summarized below:
First, the equipment
(1) barrel are dead or obstacles, easy to promote melt degradation.
(2) the machine plasticizing capacity is too small, plastic barrel plasticizing inadequate; machine plasticizing capacity is too large, plastic barrel by heat and shearing time is too long, plastic easy to aging, so that products become brittle.
(3) the top of the device is tilted or unbalanced, small top stem cross-sectional area or improper distribution.
(A) the gate is too small, you should consider adjusting the gate size or additional auxiliary gate.
(2) the shunt is too small or improperly configured, should be arranged reasonable balance or increase the size of the shunt.
(3) mold caused by poor injection cycle anomalous structure.
Third, technological aspects
(1) barrel, nozzle temperature is too low, raise it. If the material is susceptible to degradation, it should improve barrel, nozzle temperature.
(2) reduce the pre-plastic screw back pressure and speed, making the material a little loose, and reduce the degradation of plastics caused by overheating due to shearing.
(3) the mold temperature is too high, stripping difficulties; mold temperature is too low, plastic prematurely cooling, poor weld fusion, easy to crack, particularly especially high melting point plastics such as polycarbonate or the like.
(4) cavity core have appropriate stripping slope. When hard core stripping, to improve the cavity temperature, shorten the cooling time; Away when the cavity, the cavity to reduce temperature and longer cooling time.
(5) minimize the use of metal inserts, such as polystyrene large cold hematocrit brittle plastic, but not join insert molding.
Fourth, the raw materials
(1) mixed with other materials or impurities doped inappropriate or excessive solvent or other additives.
(2) Some of the plastic is heated with the steam cracking reactions occur in damp conditions, so that the occurrence of large parts of the strain.
(3) plastic recycling too many times or recycled materials content is too high, or too long in the barrel heating will make parts brittle.
(4) the poor quality of the plastic itself, such as the molecular weight distribution of a large, non-uniform structure containing ingredients rigid molecular chains occupy excessive; or contaminated, poor additive pollution, dust and other plastic doping impurity contamination is caused by brittle the reason.
Fifth, the product design
(1) plastic drain board with fecal sharp corners prone to stress cracking, chipping or thickness vary greatly site.
(2) plastic drain board design is too thin or hollow manure too.