Low smoke zero halogen flame retardant polyolefin cable material usually adopt flame polyolefin blend resin plus filler aluminum hydroxide, magnesium hydroxide, and some in order to improve longevity heat-resistant and adding suitable amount of antioxidants. Sometimes in order to reduce smoke during burning, also added some smoke inhibitor, such as vanadium, nickel, molybdenum, iron, silicon, nitrogen compounds. The mechanism of flame retardant for: when burning, flame retardant filler aluminum hydroxide, magnesium hydroxide can release water of crystallization, absorb a lot of heat; Dehydration reaction, meanwhile, will generate  large amounts of water vapor, it can dilute combustible gases, to prevent burning, also can be in material surface forming a layer of molten oxide scale of non-combustible, which cut off access to polymer hot oxygen reaction with the outside world, eventually material, self-extinguishing flame retardant

The parameters of screw:(1)screw diameter,outside screw diameter,often use 60-150mm,the diameter increase ,conveyor capacity increase(2)the screw length to diameter ratio L/D:the effective L/D when working,usually 20-40,L/D is larger,can reduce current and leakage flow,need plasticizing time is long ,such as rigid plastics,powder,or crystalline plastics.