Effect of three variables on the accuracy and variability of electroplated copper dies.

This investigation compared the accuracy of electroplated copper and stone dies. Sixty copper die replicas of a stainless steel master die were fabricated using different current settings, plating times, and backing materials. Die accuracy was assessed by measuring the misfit of a stainless steel ring machined to fit the master die. All the copper dies were more accurate than the 10 stone dies. The variability of the copper/stone dies was less than that of the stone dies (P = .011) and copper-resin dies (P < .001). There was no significant difference between the variability of the 40-mA, 48-hour copper-resin dies and the stone dies. The variability of the copper-resin dies was related to the thickness of the electrodeposit, which was a function of plating time, current, and plated surface area.