Case Study #9

Part Name: M73 Spacer

Material: 2011 aluminum

Challenge: Machine spacers of various lengths in an annual quantity of 3 million pieces per year total; length must be held to ± .0002, with good surface finish, flatness, and parallelism; and price must be held to under $.04 each.

Solution: Only Cam-driven screw machines offer the blazing speed required to approach this target price, but when used conventionally, they're generally only capable of holding tolerances of ± .001. Only through expertise acquired over decades are we able to get this sort of repeatability from these machines. Every possible source of deviation is controlled - speeds and feeds, machine temperature, coolant flow, coolant angle, tool sharpening techniques, the precision of tool setting, the geometry of the cams themselves and the resultant acceleration and deceleration of the turret and slides - uncontrolled variation in any of these factors, or in any of fifty other factors, can result in variation of the dimensions of the finished piece. This control, coupled with the use of a specially-designed form tool that faces and cuts off in one pass, enables us to produce this part in under three seconds, with no burrs.