Basic knowledge of plastic processing, PE plastic (2)

Chemical name: polyethylene
English name: Polyethylene (PE)
Specific gravity: 0.94 to 0.96 g/cm3 molding shrinkage rate: 1.5 3.6% molding temperature: 140-220 ℃
Characteristics: corrosion resistance, good electrical insulation (especially high frequency insulation), chloride, chemical crosslinking and irradiation crosslinking modification, glass fiber reinforced. The melting point of low pressure polyethylene, rigidity, hardness and high strength, small water imbibition, good Amusement equipment properties and radiation resistance; High pressure polyethylene softness, elongation, impact strength and permeability is better; Ultra-high molecular weight polyethylene high impact strength, fatigue resistance, wear resistance, low pressure polyethylene to make corrosion resistant parts and insulation parts; High pressure polyethylene thin films are suitable for, etc.; Ultra-high molecular weight polyethylene is suitable for making shock absorption, abrasion resistance and transmission parts.
Molding characteristics:
Small crystal material, moisture absorption, need not to fully dry, liquidity excellent liquidity is spring ride to pressure, molding time with high-pressure injection, uniform temperature, filling speed, pressure maintaining full. Should not be in direct gate, to prevent uneven contraction, the internal stress increased. Pay attention to choose the gate location, to prevent shrinkage and distortion.
2. Scope and contraction value is big, obvious directivity, easy to deformed. Cooling speed should be slow, mold slag hole, and the cooling system.
3. The heating time shoulds not be too long, otherwise it will decompose.
4. Soft plastic parts have shallow lateral recess, forced demoulding.
5. Melting body fracture may occur, unfavorable contact with organic solvent, to prevent cracking.