Answers to frequently occurring production technical problems of PPR pipe


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”.



There may be some problems in the production of PPR pipes. The following section summarizes some points, hoping to help you.


1、 The inner wall of the pipe is uneven: the screw temperature may be too high; or screw speed is too fast. 


2There are black stripes on the surface of the pipe: it may be that the head temperature is too high and the filter is not cleaned.


3There are bubbles on the inner wall of the pipe: the material may be affected with moisture.


4Sudden slow discharge: the temperature of the screw feeding section may be high; or water ingress into the fuselage; or the melt pressure of the machine head is low.


5Roughness of the inner wall of the pipe: the temperature of the mandrel may be low; or the fuselage temperature is too low; or the screw temperature is too high. 


6The surface of the pipe is dull: the die temperature may be too low or too high. 


7Wrinkles on the pipe surface: it may be that the temperature around the die is uneven; or the cooling water is too hot; or the traction is too slow.


8Cracks on the inner wall of the pipe: it may be that the material has impurities; or the mandrel temperature is too low; or low fuselage temperature; or the traction speed is too fast.


9There are coke marks on the surface of the pipe: the possible cause is that the temperature of the machine or the head is too high; or the machine head and filter are not cleaned; or there are impurities in the granular material; or poor thermal stability of raw materials or too little thermal stability dose; or the control temperature instrument fails.


10Large longitudinal or transverse shrinkage of the pipe: the radial difference between the sizing sleeve and the inner diameter of the die may be large (transverse); or high traction speed (longitudinal).


11Uneven pipe wall thickness: the die and th pin may not be aligned; or the head temperature is uneven; or unstable traction; or the compressed air is unstable.


12Brittle products: the fuselage may not have enough plasticization; or screw speed is too fast; or the head temperature is too low; or the resin viscosity is too high.


13、Pipe bending: pipe wall thickness may be uneven; or the temperature around the machine head is uneven; or the head cooling groove and traction cutting center are not aligned; or the holes at both ends of the cooling groove are not concentric.


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.


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