Machining: 2012

The process depends on the type of broaching being performed. Surface broaching is very simple as either workpiece is moved against a stationary surface broach or the workpiece is held stationary while the broach is moved against it. Internal broaching is more involved. The process begins by clamping the workpiece into a special holding fixture called a workholder , which mounts in the broaching machine. The broaching machine elevator , which is the part of the machine that moves the broach above the workholder , then lowers the broach through the work piece. Once through , the broaching machine’s puller , essentially a hook , grabs the pilot of the broach. The elevator then releases the top of the pilot and the puller pulls the broach through the workpiece completely. The work piece is then removed from the machine and the broach is raised back up to reengage with the elevator. The broach usually only moves linearly , but sometimes it is also rotated to create a spiral spline or gun-barrel rifling.
Cutting fluids are used for three reasons. First to cool the workpiece and broach. Second , to lubricate cutting surfaces. Third , to flush the chips from the teeth. Fortified petroleum cutting fluids are the most common , however heavy duty water soluble cutting fluids are being used because of their superior cooling , cleanliness and non-flammability.