The effect of high-pressure cutting fluid supply on the chip breakability of lead-free brass alloys

To improve machinability and in particular chip breakability, brass alloys are usually alloyed with small quantities of lead. Due to environmental and health concerns, the use of lead has been restricted in the last years. As lead-free brass alloys are progressively implemented in the industry, challenges arise due to their differing properties from traditional leaded brass alloys. One of the main challenges in automated continuous cutting processes is the worse chip breakability of lead-free brass alloys leading to longer and tangled chips. Hence, the impact of a high-pressure cutting fluid supply, as well as the impact of a chip-breaking geometry and the combined effect of both, has been investigated at different feeds. The three brass alloys CuZn37 (CW508L), CuZn38As (CW511L), and CuZn42 (CW510L) were studied at varying cutting fluid supply pressure levels and feed rates in a radial cutting operation. Cutting forces were measured, and chips were analyzed. No overall systematic impact of the cutting fluid supply pressure on the cutting forces was observed. In conclusion, increased pressure levels, a chip-breaking geometry, and an increased feed rate enhance the chip breakability of the investigated alloys.