Formability in computer numerically controlled single-point incremental forming.

摘要

Computer Numerically Controlled Single Point Incremental Forming (CNCSPIF) is the latest progression of a series of sheet metal deformation processes deriving from spinning. Using a common CNC milling machine, non-axisymmetric shapes can be made quickly and cheaply, without need for dedicated dies.; This study examines the formability limits of 1.21mm Al 3003-O that was formed into cones and truncated cones with the CNCSPIF process. Both single-pass and two-pass methods were employed, and a forming limit diagram (FLD) was developed for each. The forming limit curve (FLC) obtained from the FLD agreed with published values for CNCSPIF, with a linear trend featuring a -1 slope.; Wall thickness profiles were also studied, and the effect of varying the pre-form wall angle and offset was quantified for two-pass forming, with a zero offset and a 55-degree wall angle being the most successful for the forming criteria studied here. A limited study into the maximum wall angle achievable for different types of material and thickness was also conducted.; Two experimental shapes were studied, in partnership with industrial sponsors. An exhaust manifold heat shield was successfully formed with a two-pass CNCSPIF process, using a novel technique for designing the first-pass pre-form. A hemisphere was also successfully formed for use as a weather shield for a solar pyrometer. This geometry was formed by pioneering a CNCSPIF tool path technique that uses a series of radial sweeps as opposed to the traditional helical tool path designs.