In the extrusion blow moulding process, the strength and weight of a hollow article, such as a bottle, is controlled by an open loop control process called parison programming. The article thickness is increased and decreased by opening and closing the gap of the annular die from which the parison is extruded. The die gap is regulated according to a gap-time profile which an operator determines during start up by trial and error. / An optical sensor has been developed which can measure the thickness profile of the parison on-line just prior to its enclosure in the mould. The device will help operators to program the gap-time profile for optimum use of plastic by providing rapid feedback on the formation of the parison. It also represents an important step toward the development of closed loop control for container thickness distribution. / The device determines thickness by striking the parison at an angle with a laser beam and measuring the separation between the beams that reflect from the outer and inner surfaces of the parison wall. A prototype was built and tested. The prototype uses three lasers at different angles and can make up to 250 point measurements during a one second scan. A personal computer uses specially developed software to reconstruct the profile of the parison wall from the raw data with an accuracy of $ pm$5%.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.61319 |
| Date | January 1991 |
| Creators | Swan, Philip |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001315094, proquestno: AAIMM80325, Theses scanned by UMI/ProQuest. |
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