Producing bone screws is more economical when manufacturers use whirling as a separate operation rather than performing threading on a turning machine, according to manufacturer Leistritz. The company offers the PW-65MED, a whirling machine designed for this process. As many as five turning centers can produce blanks of various lengths for the machine.
The machine features an automatic parts loader and hopper system. The pre-turned blanks are dumped into a vibratory hopper, which orients and guides them tip-first to the staging area. Once “on deck” for the loading process, each screw is measured for length with a light beam, and the proper CNC program is selected to run the appropriate screw length. With this system, all screws within the same family can be produced without any setup changes, the company says.
With a 2.5-hp motor, the machine has a whirling speed of 12,000 rpm. It can accommodate workpieces as long as 8.5" with diameters ranging from 0.2" to 0.6". It is available with a Siemens, Fanuc or Allen Bradley control.