Rotary ultrasonic machining of CFRP/Ti stacks using variable feedrate

Abstract

Rotary ultrasonic machining (RUM) has been successfully used to drill Ti (titanium and its alloy), CFRP, and CFRP/Ti stacks. In all studies on RUM reported in the literature, feedrate was fixed during each experimental test. It has been shown that low feedrate should be used for RUM of Ti, but RUM of CFRP could be done using feedrate ten times higher. This paper, for the first time, reports a study on RUM of CFRP/Ti stacks using variable feedrate (high feedrate for CFRP and low feedrate for Ti). It also makes comparisons on RUM of CFRP/Ti stacks using fixed and variable feedrate.RUM CFRP-Ti Stacks (Text) 3

Experimental investigations on core drilling by ultrasonic-vibration-assisted grinding for hard-to-machine materials - a review

“…In their study, feedrates of 0.5 mm/s and 0.05 mm/s were chosen for CFRP and Ti respectively. Compared to the traditional constant feedrate, the cycle time for machining the stack was shorter, and the cutting force, torque and tool wear was lower under most machining conditions (Cong et al, 2013a). Diamond tool life and quality of machined parts are strongly influenced by cutting temperature, and it is not easy to measure the real temperature when using cutting field.…”

“…In addition, torque decreased with the increase of ultrasonic vibration amplitude and tool rotational speed and the decrease of feedrate in UVAG of carbon fibre composites. Also, using variable feedrate method (explained in Section 9) or cutting fluid, torque could be lower than using a fixed feedrate method or cold air (Cong et al, 2011(Cong et al, , 2013a(Cong et al, , 2012c(Cong et al, , 2012d.…”

“…The tool length of the core drill was measured by a Vernier calliper (Churi et al, 2005(Churi et al, , 2007c or observed by digital microscope (Zeng et al, 2004). Tool wear was also defined as the weight loss of the cutting tool during each test (Cong et al, 2011(Cong et al, , 2013a. Tool wear was also estimated by wear ratio which is the ratio of the volume of material removed by tool to the volume of tool wear (Prtrukha, 1970).…”

“…Seven brittle materials (Al 2 O 3 , ZrO 2 / Al 2 O 3 , dental ceramics, SiC, poly-crystalline, CMC, and silicon), two ductile materials (Ti and stainless steel) and two carbon fibre composites (C/C, CFRP) were studied. Seven of the 13 input variables were studied for ductile materials, six of them for brittle materials and only two of them for carbon fibre composites (Cong et al, 2011(Cong et al, , 2013a(Cong et al, , 2012a(Cong et al, , 2012b(Cong et al, , 2012c2012d;Ma, 2013). There is a phenomena that cutting force in UVAG was lower than that in traditional diamond grinding.…”

“…It is reported that UVAG has six to ten times higher MRR than traditional grinding , and it is about ten times faster than ultrasonic machining (USM) (Cleave, 1976). Tool pressure and torque in UVAG are low (Cleave, 1976;Cusumano et al, 1974;Cong et al, 2011Cong et al, , 2013aCong et al, , 2012cCong et al, , 2012d: lower pressure is especially helpful when drilling small holes, deep holes, or adjacent holes with thin dividing walls (Cleave, 1976). UVAG also has reduced edge chipping, breakout and damage (Cleave, 1976).…”