Four common plastic bucket lid
1, PP plastic cover:
PP plastic chemical name: pp
1. crystalline material, the moisture absorption of small, high incidence of ruptured into long-term contact with the hot metal can decompose.
2. good fluidity, but range and shrinkage values, susceptible to shrinkage. dents, deformation.
3. cooling speed, feed system and cooling system slowly cooling and controlling mold temperatures. material temperature easy orientation when the low temperatures and high pressure, die when the temperature is below 50 degrees, plastic parts are not smooth, easy to produce bad weld, flow marks, more than 90 degrees prone to warping deformation
4. plastic wall thickness shall be uniform to avoid lack, sharp corners to avoid stress concentration.
2, ABS plastic covers:
ABS plastic chemical name: acrylonitrile-butadiene-styrene copolymer
1. amorphous materials, liquid medium, moisture must be fully dry, surface gloss of plastics for long time preheating drying 80-90, 3 hours.
2.take high melt temperature Gao Mowen, but excessively high temperature decomposition (decomposition temperature of >270 degrees). high precision plastic parts, mold temperature to take 50-60, of high gloss. heat-resistant plastics, mold temperature to take 60-80.
3, if you need to solve the Weld Line, need to improve its liquidity, high temperature, Gao Mowen, or change into water and other method.
4 heat resistant or flame retardant materials, such as forming, 3-7 days after the production mould surface remains plastic decomposition products, resulting in mold shiny surface, it is necessary to clean up mold and die surface to increase the exhaust position.
3, PE plastic drum cover
Chemical name of PE plastics: polyethylene
1. crystalline material, moisture is small, not be fully dry, good liquidity liquidity pressure-sensitive, forming up to date with high-pressure injection, temperature uniformity, filling speed, holding full. should not be used directly to the gate in case of uneven shrinkage, stress increased. Note Select gate locations, preventing shrinkage and deformation.
2. shrinking and shrinking the value of the range, direction obviously, easy deformation and warpage. cooling slowly, mould set cold cave, and cooling systems.
3. heating time should not be too long, otherwise it will break down.
4. soft plastic parts when the shallow side notch, forced stripping.
5. thaw rupture may occur, should not come into contact with organic solvents to prevent cracking
4, PVC plastic
PVC plastic chemical name: PVC
1. amorphous materials, moisture-absorbing small, illiquid. in order to increase liquidity to prevent the occurrence of bubbles, plastics can be dried beforehand. mold runner system should be thick and short, gate sections should be large, there shall be no dead corner. mold must be cooled, chrome plated.
2. due to its corrosive characteristics and liquidity, the best use of equipment and tooling. Products should be required to adhere to all different types and quantities of additives.
3. very easy to resolve, and steel at 200 degrees temperature. copper contacts are more likely to break down decomposition corrosion Shi Yi. irritant gases. molding temperature range.
4. using screw-type injection molding machine nozzle, the aperture should be to prevent dead residuum. good set piece, if the inserts should be preheated.