A hybrid linear and rotary fast tool servo for diamond turning of freeform optics

This paper discusses the design of a new type of fast tool servo(FTS) equipment, which has two degrees of freedom(DOF) of linear stroke and rotary stroke, can provide the tool position trajectory of creating the freeform optics in diamond turning with more DOFs. The linear fast tool servo (LFTS) uses the air slide as its support, and it is driven by the linear motor; the rotary fast tool servo (RFTS) mainly consist of air bearing and brushless DC motor and the other components etc. The results of the calculation and the finite element analysis (FEA) show that the acceleration and stroke of the RFTS can reach to 46 g and 32 mm respectively, and its maximum bearing capacity and the stiffness can achieve to 170 N and 50 N/μm respectively; the acceleration and the stroke of the LFTS can reach to 7 g and 10 mm respectively, and its maximum bearing capacity and the stiffness can achieve to 1200 N and 950 N/μm respectively.