... high strength cast iron. Gears and shaft gears are finished with gas carburizing process and precise grounding to sequentially get ... oil seals, and bearings.6.Low NoiseAll key components are finished by precisely machining, accurate assembly, and finally tested, and ... main Measurement:The Reference Pictures of Screw Barrel : Series double screw gear box for extruder machine(PVC, PP, PE, PA, PC, ABS ...