Analytical, numerical, and experimental investigation of the influence of lubrication on the drawing behavior of copper alloy

Abstract

Environmentally friendly products are increasing demand and the challenge is to combine them with optimal efficiency in industrial processes. In cold drawing, lubrication improves the surface and dimensional quality of the workpiece, reduce tool wear, work loads, and maintenance intervention. Ester-based, vegetable-derived lubricants have interesting properties, such as biodegradability and low toxicity, but their application in forming processes has not yet been investigated despite their use in machining operations. In this work, we evaluated the drawing strength , surface roughness, and microhardness of electrolytic copper in the dry (non-lubricated) condition and using three different types of lubrication: powdered graphite, molybdenum sulfide grease, and ester-based oil, a possible environmentally friendly lubrication substitute for petroleum-derived lubricants. The drawing strength proved to be 23.4% lower when using grease and ester-based oil compared to the dry process, and the grease and ester-based oil presented the same result regarding process performance and material characteristics. Thus, combined with the fact that the ester-based oil led to the lowest friction coefficient between cooper and tool steel among the tested lubricants, it was possible to demonstrate that it can be used as an alternative to conventional products in cold- drawing operations of the tested cooper alloy.