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Computer-aided rolling of parts with variable rectangular cross-section

University of British Columbia

A computer-aided process planning scheme for flat rolling of symmetric parts with variable rectangular cross-section is proposed. As a starting point, El-Kalay and Sparling's formula for spread was found to be suitable for this application and thus was used in developing the method. Two distinct criteria were considered in the analysis, namely: kinematic and dynamic constraints. In order to control the precision of the rolled parts, provisions were made for specifying the tolerances of the finishing passes in the form of convexity constraints. Numerical formulation was used and the resulting non-linear equations were solved by an iterative method. Based on the process constraints and the numerical solution, a computer algorithm was then developed to determine the number of rolling passes required, as well as the dynamic variation of the roll gap as a function of the rolled length. Preliminary laboratory experiments were then conducted to verify the validity of the predicted results and the applicability of the spread formula in determining the process behaviour. These experiments led to the modification of the spread formula. Using the modified formula it was found that a good agreement existed between the predicted results and those of the experiments. Operating aspects were also considered. It was proposed that a control system based on the rolled length would be both simple and suitable. It was then concluded that for rectangular parts with moderate variation in shape and reasonable complexity, where formed-die rolling and die-forging are also applicable, this method has considerable advantages as it replaces the forging hardware with the rolling software.

Text

2010-07-11

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http://hdl.handle.net/2429/26327

Mechanical Engineering

University of British Columbia

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