Thermoforming is a generic term for the manufacturing of plastic components through a vacuum or a pressure forming process. The first and most critical phase in thermoforming is sheet heating. For a thick-gage plastic sheet, the combination of conduction and radiation energy, which conducts and transmits into the sheet interior, controls the heating cycle time. In order to predict the formability of a thick-gage sheet and improve production efficiency, we need to know the internal temperature of the plastic sheet during the heating phase in thermoforming. Unfortunately, the internal temperature of the sheet is impossible to measure directly. To overcome this problem, it is possible to use a soft-sensor technique, which uses the surface temperature of a plastic sheet that can be measured by infrared sensors to estimate the internal temperature of the sheet. / A soft sensor system was defined by using a finite difference equation. Experiments and simulations were performed to determine how well the soft sensor was able to predict the temperature distribution inside a plastic sheet. The sensitivities of some key parameters, e.g., material absorptivity, thermal diffusivity, view factor and oven air temperature, are analyzed and discussed.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.79232 |
| Date | January 2003 |
| Creators | Hou, Benqiang, 1968- |
| Contributors | Thomson, Vince (advisor) |
| 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 Mechanical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001984602, proquestno: AAIMQ88358, Theses scanned by UMI/ProQuest. |
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