Plastic pallet is a kind of logistics unit used in conjunction with logistics equipment such as forklifts and shelves. It can be used to store, load and transport goods. It is one of the most important logistics equipments in modern logistics and warehousing. When we buy plastic crates, we sometimes find that some crates are brittle. What is the reason? Let's take a look at it briefly.
First, the plastic tray mold
(1) If the gate is too small, consider adjusting the gate size or adding an auxiliary gate.
(2) If the runner is too small or improperly configured, it should be balanced as much as possible or the size of the runner should be increased.
(3) Poor mold structure causes abnormal injection cycle.
Second, plastic pallet equipment
(1) There are dead corners or obstacles in the barrel, which tends to promote the degradation of the melt.
(2) The plasticizing capacity of the machine is too small, the plastic is not plasticized in the barrel; the plasticizing capacity of the machine is too large, the plastic is heated and sheared for too long in the barrel, the plastic is easy to age, and the product is changed. brittle.
(3) The ejector device is inclined or unbalanced, and the top sectional area is small or improperly distributed.
Third, the plastic tray raw materials
(1) When the raw material is mixed with other impurities or is doped with an inappropriate or excessive amount of a solvent or other additives.
(2) Some plastics, such as ABS, will undergo catalytic cracking reaction with water vapor when heated under damp conditions, causing large strain on the part.
(3) If the number of plastic rebuilds is too high or the regrind content is too high, or if the heating time in the barrel is too long, the parts will be brittle.
(4) The quality of the plastic itself is not good, for example, the molecular weight distribution is large, and the content of the component containing the uneven structure such as the rigid molecular chain is too large; or it is contaminated by other plastics, the contamination of the bad additive, the pollution of dust impurities, etc. the reason.
Fourth, the plastic tray process
(1) The temperature of the barrel and nozzle is too low, and it is raised. If the material is easily degraded, the temperature of the barrel and nozzle should be increased.
(2) Reduce the pre-plastic back pressure and speed of the screw to make the material slightly loose and reduce the degradation of the plastic due to shearing and overheating.
(3) The mold temperature is too high, the demoulding is difficult; the mold temperature is too low, the plastic is prematurely cooled, the fusion joint is poorly fused, and cracking is easy, especially for high melting point plastics such as polycarbonate.
(4) The cavity core should have a proper draft angle. When the core is difficult to demould, it is necessary to increase the cavity temperature and shorten the cooling time; when the cavity is difficult to remove, the cavity temperature should be lowered and the cooling time should be prolonged.
(5) Minimize the use of metal inserts, brittle hot and cold plastics such as polystyrene, and can not be added to insert molding.
Fifth, the design of plastic tray products
(1) The product has sharp corners, notches or portions having a large difference in thickness which are prone to stress cracking.
(2) The product design is too thin or too hollow.