Search Results

A discrete event model was used to examine the effect of machine downtime and operating policy on the long-run average cost of an automotive stamping line. Operating policy refers to the selection of a target batch size and the circumstances under which a line stoppage will lead to the current batch being abandoned. It is assumed that the abandon/resume decision is based solely on the severity of the problem (ie repair cost) and the fraction of the batch completed. A method of identifying low cost operating policies is presented using data obtained from a real stamping plant. It is found that, within a single part framework, this approach results in significantly lower average costs than are currently achieved. It is also demonstrated that by varying the model parameters it is possible to measure the potential benefits arising from process modifications (eg decreased die-set times).

This work investigates the effect of elastic deformation of the press and die in a double action press on system performance during draw die forming. A simple linear elastic model of the complete press system was developed to show that the relative stiffness of system components controls blankholder force variation during the stroke. Calibration of the analytical model with data taken from a production press shows that the simple model explains real global system behaviour very well; and that varying system compliances can desensitise the press system to changes affecting the binder gap during the stroke. The experimental data suggests that real press and tool systems do not have an appropriate combination of system compliance, which causes large variations in blankholder force during the stroke. This model will be a useful tool for die designers and process engineers for assessing the potential impact of blankholder force variation during die design.

This paper identifies the need for AI based tools to supplement CAD/FEA methods. The approach discussed focuses on the capture and feedback of part based case lessons or issues that form a knowledge base for future use. Key aspects of a system to achieve this are presented. These include: Issue or problem data to be collected at source, the system to be visually based, enhance current job function, integrated with existing IT systems and work procedures, data to be readily accessible and consistent, modular approach functional access to data. The elements of a knowledge capture system for the stamping industry based on the above is discussed.