CONTROL & INSTRUMENTATION | MACHINERY Taking control
Systems to control all aspects of quality – from resin purity to coating accuracy and
product dimensions – help to ensure efficient production during part extrusion
Controlling the parameters of the extrusion process is vital if product quality is to be main- tained – and this can start from the moment raw materials are delivered. Sikora has developed an optical offline inspec- tion and analysing system called Purity Concept V – which combines a light table with automatic material control. The system analyses transparent and coloured plastic pellets. The material to be tested moves automatically through the system and contamina- tion such as black specks are visualised. The system is suitable for sample testing of produced material and for incoming goods inspection. Until now, sample testing of pellets has been carried out mainly by optically illuminating it on a light table, followed by manual inspection, says Sikora. This relies on the examiner, and provides limited repeatability. Other limitations are: the size of the contaminants; and, their classification by size. Alternative systems feed the test material into a hopper and through a channel into the inspec- tion area. This records images successively, and sorts out contaminated material. Due to the blending of the sorted out material, a clear allocation of the contamination to the graphic material as well as a follow-up inspection are impossible. Purity Concept V combines the advantages of a light table with automatic offline material control. The system moves the test material on a tray through the inspection area. Within seconds, it is inspected automatically by the colour camera – and contaminated material is marked directly on the sample tray by a beamer.
www.pipeandprofile.com
A clear allocation of the contamination and follow-up inspection are possible at any time, so the system helps quality control and process optimisation, says Sikora.
X-ray vision Further along the process are systems to control and assess product quality. Zumbach has expand- ed its range of X-ray measurement technology for single- and multi-layer products. The company says that its Rayex S static X-ray system has been developed for products such as foamed pipe and hydraulic hoses. It measures and controls a variety of dimensions – such as diameter, ovality and wall thickness – of products with up to four layers. It works for pipes and hoses of up to 80mm outside diameter. Key features include: repeatability within 0.02mm; measuring frequency up to 10Hz in standard mode; two X-ray sources positioned at a 90 degree angle; and an X-ray source that requires no water cooling.
It can be used to control an extrusion line
automatically when combined with a data acquisi- tion and processor system. When controlling line speed or extruder speed, parameters are con- trolled to the nominal value. The display shows all measurement values numerically and graphically, along with trends and statistical data. A line presentation with pictograms of the connected devices provides a clear overview to the operator. At the same time, the system reduces the wall thickness to a minimum value. Quality assurance and the reduction of material lead to a significant increase of productivity.
Main image: Sikora’s Purity Concept V combines a light table with automatic material control
� April 2018 | PIPE & PROFILE EXTRUSION 35
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
