As a result of recent testing under real production conditions, brass proved to machine at extremely high speeds on today’s advanced machine tools with little evidence of tool wear, producing high-quality surface finishes and excellent chip control, reported the Copper Development Association (McLean, VA). These findings dispel common misconceptions in the machining industry—based on or reinforced by overly conservative handbook recommendations—that lead many manufacturers to underestimate the productivity upside of brass by up to 85 percent.
In tests among five brass rod alloys, and between brass and free-machining steels, brass consistently machined faster, yielding lower machine time costs and higher metal removal rates with longer tool life. These results held true through tests of high-speed turning, end milling, and drilling.
On a modern vertical machining center, brass rod alloys—running at 4000, 2500 and 2000 surface feet/minute (sfm) respectively for turning, milling, and drilling—created little wear on carbide tools after two hours of continuous cutting. A Swiss-style CNC automatic lathe also produced 63 percent more C36000 brass parts under high-speed conditions compared to conventional speeds in an eight-hour shift, achieving a 38.5 percent reduction in machine time costs with no measurable tool wear.
Optimized speed tests for single-point turning demonstrated that at a given hourly rate, machine time cost 86 percent less for brass per cubic inch of material removed through turning than 304L stainless steel and 79 percent less than 12L14 steel. The comparison showed that brass readily maintains turning speeds of 3000 to 4000 sfm for practical production periods, more than three times the speeds achieved with 304L stainless steel or 12L14 steel. Brass also outpaced both these metals in a high-speed drilling test, completing 1000 holes eight times faster than 304L stainless steel and 2.4 times faster than 12L14 steel.