Downsize Your Turning Inserts
A white paper written by John Mitchell from Tungaloy Canada.
Many machine shops today are machining with inserts much larger than are required. There are two trends in the machining industry today that influence the decision to consider downsizing your inserts size. The first is the raw materials (tungsten and cobalt) used to produce carbide inserts are dramatically increasing in price. The second is manufacturing technology is advancing and parts to be machined are considered “near net”. That means the unmachined part is near its net size or there is little material to be removed. Over 75% of the turning market takes depth of cuts of 0.117" (3mm) or less. Yet many machine shops insist on using large size inserts. The most common turning insert sold in North America today is a CNMG 432. This insert is capable of almost 0.250" (6.35mm) depth of cut. Yet as mentioned earlier over 75% of the machining industry takes cuts of less than half of that depth. This seems wasteful.