Extrusion International 1-2018

31 Extrusion International 1/2018 end of the line allows the integration of the measured cold diameter value. This allows the determination of the shrinkage, which can thus be fed back within the process to realize optimum configuration. Similar approaches generate quality improvements in pipe extrusion. At the beginning of the process, the ec- centricity of the pipe must be brought under control, then the wall thickness and finally outer diameter as quickly as possible. The optimization of the wall thickness and the monitoring of the outside diameter is also ensured by the combined and cost-effective ultrasonic and laser mea- surement technology from Zumbach. Accurate process monitoring and quality control during cable and pipe extrusion In the extrusion of cables or pipe jackets, UMAC ® ultra- sonic measurement ensures early notification of prod- uct centralization and achieved Wall thickness. UMAC ® measures and controls parameters such as eccentricity and wall thickness for up to five layers of materials at a maximum of eight individual measuring points around the circumference. Additional installed ODAC ® or MSD ® diameter measuring heads benefit by checking the di- ameter and ovality. Using these technologies, allows the manufacturer to closely monitor the extrusion processes and thus continuously maintain the quality requirements. Dual Loop Strategy maximizes quality on extrusion lines Control solutionssuch as Zumbach’s dual-loop method, as example,takes into account theproductpropertiesin both the hotand cold conditions.The resultant reported data is determined from a combination of thediameter measure- ment using ODAClasermeasuring heads and UMAC ultra- sonic eccentricity and wall thicknessscanners. Wherever several ZUMBACH systems are used in com- bination, remarkable successes can be achieved in DLP measurement and control. Considerable thought should always be given to investing in several high precision and reliable control technologies within the extrusion line. After all, global material costs are rising just as fast as quality requirements. Whether it is quality improvement for very precise cables or further material savings for commodity tubing – with the ZUM- BACH hot end dual loop control strategy, the extrusion can be monitored and controlled even more precisely and quickly. The unique and cost-effective process exploits the bene- fits of ultrasonic measurement and perfects it in combina- tion with laser scanner technologies. The intelligent solution offered by the ZUMBACH control strategy makes allowance for the product’s properties at the hot and cold ends of the line. It utilises data from the diameter measurement, determined from the ultrasonic eccentricity and wall thickness scanner UMAC ® . These data measurements are automatically adjusted based on the data from the ODAC ® laser diameter scanner at the end of the line and evaluated.This creates a very fast control feedback loop (due to the short distance from the point of change to the point of measurement) while still basing the control decisions on the final diameter mea- surements.Using this dual loop, transient deviations can be minimised, in turn leading to a significant reduction in standard deviation and ultimately an increase in the pro- cess capability index (CPK). ZUMBACH Electronic AG P.O. Box, CH-2552 Orpund, Switzerland www.zumbach.com Customer specific solution with ODAC ® and UMAC ® gauges in an extrusion line for products up to 500mmOD Dual Loop configuration with UMAC ® at the hot end, and ODAC ® at the cold