Many machining applications require custom solutions. Form tools, which are custom inserts, are often a special order choice among machine shops because of the advantages they offer—cycle time, accuracy and finish—which overall are a cost-effective pick for machining a complex cylindrical profile.
The advantages of form tooling are made obvious in this video comparing single-point turning and machining with a form tool. The time benefit is especially highlighted: The in-out stroke of the form tool allows the profile to be machined in about one-third of the time.
This type of tooling is also more accurate than standard tooling because a turning tool involves two machine axes where a form tool uses only one machine axis. Fewer moving elements contribute to less error, which can make achieving tight tolerances easier.
Another benefit to using form tools is finish. With a single-point tool, inevitably there are cusps between rotations of the workpiece as the cutting edge travels along the contour. A form tool omits these cusps, because the entire segment of the part represented by the form is machined in a single plunge.
To read further about form tools and the additional advantage of tool life, read “Form Tools on CNC Lathes.”
As always, if there’s a topic you would like to see covered here, or if you have any comments about past columns, please email me.