Surface and Edge Quality Variation in Precision Machining of Single Crystal and Polycrystalline Materials

Abstract

The surface and edge quality of single crystal and polycrystalline copper workpieces has been observed to vary significantly as a function of crystallographic orientation. At the precision scale, the chip formation process is influenced by the microstructure of the material, such as grain boundaries and grain orientation in polycrystalline materials, and crystallographic orientation in single-crystal materials. Such variation in the microstructure has a significant effect on the resulting surface, edge, and burr topography.

A Review of Burr Formation in Machining

“…In general they confirmed that burr size is reduced and cutting ability increased as drill size decreases. Min et al [15] found that grain orientation affected burr formation in drilling of polycrystalline copper, Fig. 14. A single material may produce a ductile-like cutting mode in one grain and brittle-like cutting in another, indicating that favorable and non-favorable cutting orientations for good surface and edge condition exist as a function of crystallographic orientation.…”

“…Min et al [15] conducted micro-fly cutting and microdrilling experiments on single crystal and polycrystalline OFHC copper in order to understand the effects of crystal orientation, cutting speed, and grain boundaries on surface roughness, chip formation, and burr formation. Certain crystallographic orientations were found to yield rougher surface finish, as well as significant burrs and breakout at the tool exit edge.…”

“…Sugawara and Inagaki [20] investigated the effect of drill diameter and crystal structure on burr formation in microdrilling. They utilized both single crystal and polycrystalline iron [15] with a thickness between 0.06 and 2.5 mm and high speed twist drills with diameters from 0.06 to 2.5 mm. In general they confirmed that burr size is reduced and cutting ability increased as drill size decreases.…”

Variation in Machinability of Single Crystal Materials in Micromachining

“…al. has demonstrated variation in surface finish and cutting force in continuous face turning of single crystal copper [3], and work done by the authors has demonstrated a significant change in chip morphology and surface/edge condition in microdrilling and ultraprecision flycutting [4], and in ultraprecision machining of single crystal copper [5]. Brinksmeier et.…”

Experimental study of crystal anisotropy based on ultra-precision cylindrical turning of single-crystal calcium fluoride

“…To shorten polishing time, it is necessary to make a smoother surface at the ultra-precision cutting process stage [8][9][10][11]. In addition, the single-crystal CaF 2 's characteristics indicate hard brittleness and crystal anisotropy [12][13][14]. Yan [15] showed that crack initiation depended on cutting direction and that the http://dx.doi.org/10.1016/j.precisioneng.2014.11.007 0141-6359/© 2014 Elsevier Inc. All rights reserved.…”