Chip control in tube turning using a high-pressure water jet

Abstract

A stable chip control using inserts with integrated chip formers is difficult, especially if the feed rate or cutting depth is not within the range recommended for the insert. This paper shows the possibility of controlling the chip upcurl radius in turning by using flat inserts without any chip formers. An experimental study was made of the skew cutting of an end of a pipe using a plain water jet with a pressure of up to 80 MPa and a flow of up to 8 l/min. The jet was directed perpendicularly to the cutting edge into the tool/chip interface. Investigations show that the chip upcurl radius can be successfully controlled. A correlation between water jet power, jet momentum and upcurl radius is presented and discussed. An empirical model of the above-mentioned correlation is also suggested.

High performance cutting of advanced aerospace alloys and composite materials

“…Moreover, the mechanical jet force acting on the chip's bottom side acts as a liquid chip former, decreasing the upward bending radius of the chip. This leads to a reduced tool-chip contact zone by up to 50% in comparison to conventional flood cooling [44]. The lubricoolant supply pressure and flow rate are the major factors influencing hydraulic jet force and hence, the chip bending [44,100].…”

“…This leads to a reduced tool-chip contact zone by up to 50% in comparison to conventional flood cooling [44]. The lubricoolant supply pressure and flow rate are the major factors influencing hydraulic jet force and hence, the chip bending [44,100]. Sharman et al [198] achieved a 40% reduction in tool temperature by the use of high-pressure lubricoolant supply compared to conventional flood cooling.…”

“…In this regard it has to be prevented that the flowing chip fragments captured by the high-pressure jet do not collide with the newly generated workpiece surface which may be damaged in this way. This undesirable effect can be influenced by the geometrical jet alignment and the jet force point of impact [44,113].…”

Machining of nickel-base, Inconel 718, alloy with ceramic tools under finishing conditions with various coolant supply pressures

“…The chip curl radius also depends on the coolant pressure and the flow rate. Therefore at a given power, smaller chip curl radius could be achieved at a lower coolant pressure with a high coolant flow rate [4]. The chips generated when machining with ceramic tools under both conventional and high-pressure coolant supplies comprise of highly segmented needle like (compressed) chips joined together in a continuous fashion.…”

“…High-pressure cooling technique was first proposed and tested by Pigott well [2] who demonstrated a seven-to eight-fold increase in tool performance when machining steel. The cooling technology has now been perfected by the provision of efficient high-pressure cooling systems and tooling which is very appealing to industry in terms of costs [2][3][4][5][6].…”