Metal Forming Force Measurement

Abstract

Clips and Clamps Industries (CCI) produces small metal parts, many of which are formed using metal forming fourslide machines. CCI’s fourslide machines have been experiencing failures and increased maintenance due to the usage of high-strength steels that require more force to form. In order to minimize damage and maintenance, CCI has asked to implement a sensor that detects the forces on the slide while the machine is in operation, to incorporate a safety control to automatically shut off the machine when a programmed force is exceeded, and to calculate the maximum tonnage rating on the forming section—specifically the front slide as this is the area prone to failure. This design must also be scalable so that it may be implemented on both the smaller, S3F and larger, S4F machines. After initial research and defining the project scope, finite element analysis simulations on the slide and gathering feedback from sponsors at CCI and professors at the University of Michigan, the final design was solidified as a Wintriss strain link sensor bolted to the top of the slide. Through Solidworks CAD models, data was gathered regarding strains on the slide to justify the location of the sensor while assuring that the design would not hinder the fourslide machine operation or compromise safety. The risk associated with the design has been assessed in both a risk analysis and FMEA, raising concerns with safety and potential failures. The final design has been manufactured and was installed in a fourslide machine at CCI. To validate whether the design meets the project requirements, the strain link was calibrated with a load cell to ensure accuracy as well as tested to ensure functionality of auto-shutoff capability. Additionally, through theoretical modeling including finite element and fatigue analysis, the maximum tonnage rating was determined to be 4.5 tons. This maximum tonnage rating will be validated and further refined through empirical testing over time carried out by CCI.