Process Control
During start-up, samples are taken frequently and all the important variables of the tubing are measured. This includes controls regarding different attributes like cracks, cavities etc. When the extrusion process is stable and the tubing is within specifications, the production starts.

The extrusion process is monitored during the entire production run and samples are taken frequently measuring all variables like OD, wall-thickness, ID, eccentricity, ovality and all extrusion parameters like pressure, temperatures etc are documented and used as a reference for the next extrusion run. For details on equipment used see Capabilities/Process Control.

The outer diameter and ovality are always measured in-line with Zumbach laser beam equipment. The OD is documented in a control chart, which is kept in our files for six years.

All operators are always responsible for the quality of each batch they produce and they take samples randomly from each spool, bag or can. These samples are used in the final inspection for the batch release.