Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.
Polypropylene pipe is a kind of polypropylene product with low melt index and high molecular weight. It is non-toxic, tasteless and light. The density is 0.9-0.91g/cm3. It has excellent mechanical properties, chemical stability, aging resistance, excellent processability and outstanding heat resistance, and has good resistance to stress creep cracking.
Production process flow
pipe material - drying in hopper - pipe extruder - vacuum sizing - cooling - traction – cutting
Single screw extruder is generally used in the production of polypropylene pipes. Due to the high quality requirements of polypropylene pipes, the outer diameter, wall thickness and other dimensions of pipes should be strictly controlled within the standard range, otherwise, the connection between pipes and pipe fittings is prone to quality problems. As the pipe is used indoors, the inner wall of the pipe is required to be smooth. The pressure of polypropylene pipe is high, up to 2.0MPa, and the pipe wall is thick, which puts forward higher requirements for extrusion equipment. Therefore, the extrusion equipment shall have the following main properties.
1. The feeding part shall be equipped with drying device, and it is better to use automatic weighing to ensure that the weight of each meter of pipe is consistent and the wall thickness is uniform.
2. The extruder should have good plasticization and high extrusion capacity.
Due to the high molecular weight and melt viscosity of polypropylene, the length diameter ratio of extruder screw is required to be less than 30 to ensure good plasticizing ability and stable extrusion.
3. The screw structure shall be advanced and reasonable. The temperature of each section of extruder and head is automatically controlled to ensure accurate temperature control and normal instrument display.
4. The cooling of polypropylene pipe is very important because the pressure grade of polypropylene pipe is above 1.0MPa. In addition, the pipe wall is thick, so the cooling length of the production line is generally required to be more than 24m to fully cool the polypropylene pipe, so as to improve the production efficiency and stabilize the pipe size. If the cooling is not good, the pipe is easy to deform in production. The spray cooling method can make the cooling around the pipe uniform and the pipe is not easy to deform.
5. It shall be balanced and powerful and synchronized with the extrusion speed. It is best to realize the closed-circuit control of the extrusion production line to ensure the uniform wall thickness of the pipe. If the extrusion speed is increased, the change of pipe quality will not occur.
If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to contact for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.