Measurement of the Preston coefficient of resin and bronze bond tools for deterministic microgrinding of glass

Deterministic microgrinding technology applies a bound diamond abrasive tool positioned by a Computer Numerically Controlled (CNC) machine to generate precision optical components. The ease of work material removal during the grinding process is often characterized by the specific energy or the Preston coefficient. For a given part and process, these two parameters also indicate the tool/abrasive performance. The Preston coefficient of a resin bond tool with 2–4 μm diamond abrasives under different process parameter combinations has been measured with BK7 as the test glass. The Preston coefficient of a similar bronze bond tool was also measured for comparison. Experimental measurements show the resin tool behaves qualitatively differently than the bronze tool in a multiple pass grinding process. The measured Preston coefficient of the resin tool was two to three times smaller than that of the bronze tool and decreased rapidly as pass number increased. A plot of the Preston coefficient versus resin tool bond wear suggests that excessive tool wear reduces the tool's cutting efficiency, resulting in a rapid decrease in the Preston coefficient.