Analysis on Extrusion Quality of Rigid Plastic Pipe Produced by Plastic Extruder Production Line

There are many kinds of plastic pipes produced by plastic extruder production line. Generally, the pipes can be simply divided into two kinds: plastic hose and plastic hard pipe. Among them, the rigid plastic pipe is called rigid plastic pipe. Generally, PE, PP, PVC and other resins are used as the main raw materials for production. How to solve the quality problems of extrusion molding by extruder? This paper analyzes several common problems.

1、The error of wall thickness of circular section of plastic pipe is too large

① In general, we need to analyze the concentricity accuracy of the die and the mandrel in the forming die after assembly. When the error between the two parts is large, the gap of the molten material flow channel between the two parts will be uneven, and eventually the wall thickness of the plastic pipe will appear too large error. At this time, we need to let the field operators adjust the concentricity accuracy of the two parts.

② If the pipe extruder production line can normally produce for a certain period of time, but after working for a period of time, the pipe wall thickness size error suddenly appears. This is mainly because the adjusting bolt used to adjust the gap between the die and the mandrel is loose. At this time, the on-site operators need to fine tune and tighten the adjusting bolt to make the extruder production line return to normal production.

2、The wall thickness error of longitudinal section of plastic pipe is large

① First of all, we need to find the problem from the traction equipment of the pipe extruder production line, which is generally caused by the unstable traction speed of the traction machine. At this time, we need to let the on-site maintenance personnel carry out the troubleshooting work on the transmission system of the traction machine. If it is confirmed that there is a problem with the tractor equipment, it needs to be repaired and restored in time to ensure normal production.

② There is another reason that the probability of occurrence is also large, mainly because the heating temperature of the extruder barrel fluctuates greatly, resulting in the instability of the extruding amount in the extruder, or the instability of the screw speed in the extruder will also cause this kind of quality problem. We need to regularly check the temperature control monitoring and spindle speed of the extruder, and need to ensure the normal operation of the monitoring components.

3、Brittle plastic pipe products

① The plasticization quality of raw materials did not meet the requirements (including uneven plasticization of raw materials and low plasticization temperature of raw materials). The plasticizing temperature of raw materials should be increased appropriately, and the screw structure should be re-selected if necessary.

② The raw materials of some types of plastic pipes need to be dried during the production of extruder. If the moisture and volatiles in the raw materials are not removed completely, the finished plastic pipes will be brittle.

③ The compression ratio of the forming die is small, so the compression ratio of the forming die to the molten material should be properly increased.

④ The size of the straight section between the die and the mandrel is too small, which leads to the obvious longitudinal fusion line in the pipe blank forming and makes the pipe brittle. The die structure should be modified.

⑤ Too large proportion of filler in raw materials is also a factor that makes the pipe brittle, so the formula of raw materials should be modified.

Above are some analyses on hard plastic pipe extrusion molding quality problems of plastic extruder production line. If there is a demand for pipe extruder production line, you are welcome to contact us. As a manufacturer with a complete set of extruder production line equipment for nearly 30 years, Ningbo Fangli Technology Co., Ltd. has a lot of equipment manufacturing experience. We will provide you with professional technical guidance and equipment procurement suggestions.

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