Experimental study on quality of PCD tools machined by different electric discharge grinding processes

Guangxian Li,Songlin Ding,Shoujin Sun,Mohammad Zulafif Rahim,John Mo,Wei Meng

doi:10.1080/23311916.2016.1228234

Guangxian Li, Songlin Ding + Show 4 more

Open Access

https://doi.org/10.1080/23311916.2016.1228234

Copy DOI

Abstract

AbstractPolycrystalline diamond (PCD) is a promising tool material which is utilized to cut difficult-to-machine materials used in aerospace industry. Because of its ultra-hardness, electrical discharge grinding (EDG), a variation of electrical discharge machining, is often adopted to manufacture PCD tools to reduce manufacturing time. This paper investigates the quality of PCD inserts manufactured by two different EDG eroding methods: “2-step machining” and “3-step machining”. Surface roughness and residual stress were investigated after EDG process. An orthogonal cutting experiment was conducted to test the performance of each PCD insert. PCD tools machined with the two methods do not have significant difference in surface roughness. The residual stress status changed from compressive to tensile after EDG process. Also, after being eroded by 3-step EDG process, there was an over 30% declination of residual stress compared with 2-step machining. The results of the orthogonal cutting test showed that the ...

Highlights

Titanium alloys have been widely used in aerospace industry in recent decades because of their outstanding properties including low density and high strength (Park, Beal, Kim, Kwon, & Lantrip, 2011)
Two kinds of electrical discharge grinding (EDG) machining strategies were investigated through experimental research and a comparison of the tool quality of eroded polycrystalline diamond (PCD) inserts was conducted
Based on the results of Raman spectrum, PCD consisting of larger grain size had smaller residual stress after EDG

Summary

Introduction

Titanium alloys have been widely used in aerospace industry in recent decades because of their outstanding properties including low density and high strength (Park, Beal, Kim, Kwon, & Lantrip, 2011). The surface of PCD tools can be ground by using a diamond grinder wheel This abrasive grinding process provides really good surface roughness and sharp cutting edge its machining efficiency is extremely low. Different from conventionally grinding which removes material mostly through physical abrasion, EDG erodes PCD by generating high-energy plasma between the workpiece and the metallic electrode which reduces the machining time significantly. Except the first type which contributes to the removal of workpiece materials, other states are abnormal discharges Both short and open circuit reduce EDM erosion efficiency because effective plasma channel were not generated during the ontime period. Because of the high temperature generated in the EDG process, thermal effect, which is inevitable, is detrimental to the quality of machined surface and affects the life and performance of PCD tools (Yadav, Jain, & Dixit, 2002). There was a comparison about the performance of PCD inserts machined by 2-step erosion and 3-step erosion respectively, which intended to examine the fracture resistance of PCD structures

Findings

Experiment

Conclusion