I am designing a flexure bearing for a small motion application (+/- 1.5 mm) using a small voice coil motor. Room temperature operation. Load barely 15 gm. Compact.
Required life: 4 years at 1 stroke every 2 seconds.
Critical specifications: At any point in the range of motion (i)repeatability on the lateral position of axis better than 1 micron (ii) repeatability on tilt of axis, better than 2 arc minutes. Most of the times the actual motion will be not more than 1 mm towards one end of the entire range ( i.e. motion between 0.5 mm and 1.5 mm from undeformed position). So the flexures would not be fully reverse stressed. I am thinking of 0.1 mm thick discs of AISI 420(Hardness HRC 60).
i) Any comments on this or any other flexure material, hardness, heat treatment, fatigue data (SN curves) etc. ?
ii) Know some good sources of high quality flexure material(AISI 420 or other)?
ii) Instead of flexures, how about sliding bearing with a controlled clearance around a cylindrical tube (around 10 mm) which can be preloaded from outside the cylinder with a permanent magnet? Feasible?
Low friction coating?: Diamond? Graphite? Ceramic?
I guess PTFE wear rate may be high. Any experience with
any of these or other coatings?
How about storming brains?
Thanks a lot