Strategy for minimization of deformation due residual stresses after machining

Important results from the project

The project aimed to develop and apply a methodology based on the Contour method to predict residual stresses and deformations due to relaxation after processing. The research included various parts such as selection of parameters for wire sparking (EDM) to section the detail with minimum impact, validation of GOM measurement data, multivariate interpolation of the surfaces from large measurement data, compensation measures to minimize the estimated deformations, etc. The methodology implemented in forging at Forgex AB and in processing at LEAX AB for an auto component.

Expected long term effects

The methodology is intended to support process planning and production personnel in the manufacture of precision components with tight tolerances. The entire methodology can be coded (programmed) and provided as a tool for RS and deformation prediction. Integration of the tool with other process planning tools can enable setting the right process parameters considering post-machining deformations and even plan for compensation strategies to minimize the estimated deformation.

Approach and implementation

The development work was planned and carried out around the two industrial cases, one with forging and another with milling operation with the same auto component. The EDM operations, the CMM measurements and the calculation work were done at KTH and RISE. The tool holder with vibration damping was developed by ETP Transmission while vibration measurements were made by Acoutronic AB. The methodology as a generic tool is a future development plan to make it available to Swedish small and medium-sized companies.