This troubleshooting guide will help you:

• analyze some of the problems encountered in the manufacturing of pipes;
• determine the potential causes
• find solutions
  

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Problem: Sharkskin effect

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Causes	Solutions
The high viscosity melt leaves the die above a critical shear stress, which leads to pipes surface irregularities	Lower the melt viscosity by using high flow polymers or higher processing temperature Use processing aids, like fluoropolymer, which coat the pipe extruder. As a result, the threshold of critical shear during extrusion is moved forward and the surface quality is improved at similar throughput

 

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Problem: Agglomerates at the surface of the pipe pressure test failure

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Causes	Solutions
Undispersed pigment Polymer gels Oxidized particles Contamination	Contact masterbatch supplier, review masterbatch selection Check dilution resin quality Ensure machine is clean Use thermally stabilized raw materials Use anti-oxidants during shut-down period

 

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Problem: Taste and odor in drinking water pipes

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Causes	Solutions
Bad raw materials selection Inappropriate process conditions leading to excessive polymer degradation	Check dilution resin quality Contact masterbatch supplier, review masterbatch selection Adjust process conditions to minimize oxydation