At Domfer Metal Powders, the ball milling operation is critical since it determines many characteristics of the final product, such as density, green strength, compressibility and dimensional change. Highly variable input material properties and operational procedures accompanied by poor product feedback frequency generate large variations in powder properties. The goal of the research is to develop a model-based control system for the ball milling process of metal powder. The following research objectives are aimed at reducing process variations while maximizing throughput: include ball mill physics into design and computer models, develop control strategies and computer architectures for real-time control, and develop process monitoring and fault diagnosis techniques. / Ball mill size reduction theory is presented as a basis for process characterization. Next, process physics are described along with the measurability and controllability of the variables. Then, plant trials are performed to define system behavior and performance specifications of variables and sensors. After that, a sampler for metal powder is developed to automate the entire sieve analysis process. / A new ball mill model is created for open-circuit dry ball milling of metal powders. The process model is a combination of rules, equations and heuristics and is implemented using an agent based architecture that can deal with multiple data streams and a network of related sub-models of different sizes and operating time scales. / The model architecture is integrated using a programmable logic controller. Control and monitoring algorithms are developed in low-level PC language. A performance plant trial validated the control system and demonstrated that ball milling product specifications, namely size distribution and apparent density, are achievable and maintainable at a 99.7% confidence interval. This new technology will endow Domfer with a serious lead in metal powder manufacturing. / Key words. model-based control, ball milling, metal powder.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.102157 |
| Date | January 2006 |
| Creators | Rail, Alexandre. |
| 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 | Doctor of Philosophy (Department of Mechanical Engineering.) |
| Rights | © Alexandre Rail, 2006 |
| Relation | alephsysno: 002341431, proquestno: AAINR25235, Theses scanned by UMI/ProQuest. |
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