1. The ratio of length to diameter:
The flow performance of PP-R is poor. Therefore, when selecting extruders, the length diameter ratio (L:D) of screws should be considered to be more than 28:1 (30-33), and the best extrusion die is low pressure extrusion die.
2. Cooling methods:
PP-R is a semi crystalline plastic, its pipe processing technology is relatively strict control, and the cooling temperature is especially important. The longer the cooling time and the higher the temperature of the cooling water will cause the shrinkage of the pipes. If the cooling is too low or too fast, the residual stress will be too large, so that the impact resistance of the pipes will be low when they are impacted.
3. Pipe fittings:
The two important factors of the PP-R pipe are the cooling of the die and the depth of the pipe socket. In addition if there is a block of metal fittings with metal insert have certain requirements, otherwise it will cause in the process of using the junction leakage. Most of the problems in the PP-R system are in pipe and pipe fittings.
From: PPR Pipe Extrusion Line