Automation of Electrospark Deposition of TiCp/Ni on RSW Copper Electrodes

Abstract

Electrospark Deposition (ESD) is a specialized micro-bonding process which is used to coat a base material, known as the substrate, with a stronger, tougher, and more durable top layer, the electrode. Short durations of electrical pulses ranging from milliseconds to microseconds are used to deposit the electrode onto the substrate. This process can be used to repair damaged parts, tools or equipment, or to improve and extend tool and equipment life. The objective of this study is to develop a better understanding of the TiCp/Ni Metal Matrix Compound (MMC) coating process on RSW electrodes for the purpose of automation. Key aspects of the process are identified to aid in developing a method and approach for process automation. In order to test the effects of automating this ESD process three automation solutions were considered and tested. The first was a Manual-Automated Hybrid setup which involved the use of a manual vibrating TiCp/Ni electrode applicator which was mounted on a CNC lathe. The second solution was the novel Actively Controlled Rotating and Reciprocating mechanism which replaced the vibration of the manual applicator with an actively controlled reciprocating mechanism and added rotational control of the TiCp/Ni electrode. The third solution was the novel Actively Controlled Rotating and Vibrating mechanism which used the rotational portion of the Actively Controlled Rotating and Reciprocating mechanism but replaced the reciprocating mechanism with a vibrational one. Observations of initial tests lead to an understanding of how the TiCp/Ni electrode wears during the process while using a manual applicator as opposed one of the novel mechanisms and helped to solidify a method to ensure even wearing of the TiCp/Ni electrode for automation. Further testing of the Actively Controlled Rotating and Reciprocating mechanism provided information about the electrical characteristics of the process and the effects of these results on the process. These test results were used to develop a constraint on the contact duration between the TiCp/Ni electrode and the RSW Copper electrode. Force measurements of the manual operators at Huys Industries Ltd, the Actively Controlled Rotating and Reciprocating mechanism, and the Actively Controlled Rotating and Vibrating mechanism were used to identify differences in the process results based on the mechanism used. With the use of this data an upper limit for the contact force for this process was specified in order to ensure damage free coatings. The Actively Controlled Rotating and Vibrating mechanism was used to specify a minimum travel speed for the TiCp/Ni electrode along with a minimum number of passes required to ensure gapless coatings. The Actively Controlled Rotating and Vibrating mechanism produced relatively decent coatings of TiCp/Ni on the RSW Copper electrodes and serves as a proof of concept and basis for automation of this process.