A portable electrochemical machining surface preparation system for use in the field of residual stress measurement

Strain gauge residual stress measuring techniques require a smooth site surface for optimum bond performance. Mechanical metal removal techniques are generally used for surface preparation, although these may induce operator dependent residual stress which distorts the original stress distribution. The problem becomes more significant if subsurface conditions are to be evaluated by removing material, especially when hard, tough or strongly work‐hardening alloys are being investigated. To avoid the errors caused by surface preparation, the operator independent metal removal alternatives adopted have been electrolytic polishing and chemical etching. However, these methods have slow removal rates and can be hazardous to health, factors which limit their general use for residual stress measurement surveys.