Production issues of PVC pipes

The production of PVC pipes has relatively high process requirements and is difficult. The problem of uneven inner and outer walls of the pipes often occurs. The conventional analysis directions include the following:

The unevenness manifested as internal and external roughness is mainly reflected in:

1) Impurities, uneven distribution of additives, or the use of expired resins in raw materials can lead to poor material flowability during processing, thereby affecting the surface quality of pipes and forming surface roughness.

2) Unstable extrusion temperature: Excessive or insufficient temperature can affect the melting state of PVC, leading to PVC decomposition, surface yellowing or unevenness, or insufficient flowability, resulting in an uneven or rough surface.

3) Mold wear or improper design: The mold may experience wear during use, or the design may be unreasonable, which can also lead to wavy or uneven surfaces on the surface of the pipe.

4) Insufficient lubrication can cause poor demolding performance, rough and uneven inner and outer walls of the pipe, and excessive lubrication can lead to problems such as cracking.

The phenomenon of wave like patterns is mainly manifested in:

1) Uneven cooling: Uneven cooling of extruded pipes leads to differences in surface tension and the appearance of wavy patterns. Uneven cooling water temperature or cooling rate can cause this phenomenon.

2) Unstable traction force: The traction force of the tractor is unstable, resulting in uneven stretching of the pipe surface and causing wavy patterns.

3) Uneven extrusion speed: Fluctuations in extrusion speed can also cause wavy patterns on the surface of the pipe, which may be caused by unstable transmission systems or screw speeds of the extruder.

Solution

Regarding the surface issues in the production of PVC pipes, improvements can be made from the following aspects:

1. Equipment optimization: Regularly inspect and maintain equipment, especially molds and tractors

2. Optimize raw materials and formulas: Use high-quality and standard PVC resin to avoid using expired or substandard raw materials.

3. Accurately control the cooling and traction process: avoid tension differences caused by temperature differences during the cooling process.

4. Choose appropriate lubricants: Using efficient lubricant combinations can effectively reduce friction, improve fluidity, promote plasticization processes, and reduce the occurrence of surface defects. The polyester homopolymer and polyester wax series products provided by Ruile Chemical can effectively help customers balance lubrication performance, improve plasticization, reduce precipitation, and enhance the appearance quality and mechanical properties of pipes, showing outstanding performance.