diy cnc rotary table factory

Seriously, backlash is highly relevant in ANY cnc machine. Backlash compensation is often thought to be some magic cure, but in reality, for amounts more than a few tenths, its about as effective as nailing a 2x4 to the pelvis of a one-legged man and declaring him ready for the olympics. In a machine tool, putting the tool where you want it is of low signifigance as compared to keeping it where you want it. Forces are constantly changing direction and this allows the tool to wander within the extremes of whatever backlash is present.

When there"s backlash or slop between the driver and the feedback device, the situation is made worse instead of better because the system will typically be unstable, particularly during times when cutting forces make the table move. The encoder moves a couple counts, and the motor tries to move it back to position. But, it may have to move thru some of the backlash before the encoder moves. Now the backlash zone has moved from its original position, the force direction from the cutter changes, and the table moves again. This time its changed the encoder by 4 counts. The motor moves the screw, and the backlash zone has moved again. This happens continually during the cut, and the motor is always trying to keep the encoder in the commanded position. It can"t do it, but it hunts back and forth in a never ending cycle of trying to keep it in the right place. It hasn"t helped or compensated for the backlash in any useful way, and generally serves to make the backlash more evident and the process less controllable than if the encoder was mounted directly to the motor shaft.

About 3 years ago I bought a cheap rotary table that I converted by taking off the handle and replacing with stepper motor. I used thrust bearings and whatever I could think of to minimize the backlash but it was a big FAIL. The internal worm gear mechanism was so sloppy that backlash was measured in degrees. Its been sitting on the shelf collecting dust. Since then I found out about Harmonic Drives and what high end CNC/Robotic systems use for rotational axis. A new harmonic drive is big $$$$ so eBay to the rescue. The gear head I used is planetary but made by Harmonic Drive Systems so it is very precise. It’s simple and just the right size for my small cnc. Since the stepper motor, gecko drive and gearhead was bought off eBay, it wasn’t that expensive. Under $150. I had upgraded my mini lathe to a bigger 5″ 3 jaw chuck. The 3″ chuck wasn’t being used anymore so I put it on the gearhead.

ATS Systems is a national leading machine tool accessories and automation supplier delivering reliable solutions with unwavering support that increases manufacturing productivity and throughput leading to profitable results for its customers. For over 20 years, ATS has installed over 135K machine tool accessories and automation systems allowing customers to achieve productivity gains of over 50% and increasing profitability.

A rotary table used in conjunction with a mill allows a machinist to produce virtually any part they can design. Sherline’s rotary table is a precision piece of equipment that has been designed to work with their vertical milling machines, however, it can be used on any mill whenever the small 4-inch size would be an advantage. The only limits are size, not complexity.

The table is 2″ high and 4″ (100mm) in diameter. The main components have been machined from solid bar stock steel, and the complete unit weighs seven pounds. The table has been engraved with a laser, giving sharp and precise lines every 5°, numbered every 15°. These lines are calibrated with the 72-tooth worm gear that is driven by the handwheel. The handwheel is divided into 50 parts, making each line on the handwheel 1/10°. This allows a circle to be divided into 3600 increments without interpolation. Seventy-two revolutions of the handwheel rotate the table one revolution.

The rotary tables can hold more weight when they are not under a continuous load. Click on the Video tab above to see examples of different weights and uses for our rotary tables.

The table T-slots are identical to those used on the Sherline mill and lathe, making the vast line of Sherline tooling available for use with this product. Two hold-down clamps and T-nuts are provided with the table. Also included is an adapter that allows Sherline’s 3- and 4-jaw chucks to be screwed directly to the rotary table. An optional right-angle attachment is available (P/N 3701) to mount the table in the vertical position to further increase its versatility. With the table mounted vertically, an optional adjustable right-angle tailstock (P/N 3702) can be mounted to the mill table. It is used to support and stabilize the other end of long work held in a chuck or otherwise attached to the rotary table.