For some time now, I have had the thought of building a linear actuator device that will move a sled back and forth on the top of my table saw - to make special precision cuts over and over. I have read a little on what the options are, but when I actually go looking for parts to buy, I get a bit overwhelmed!
I need the actuator to advance the sled fairly quickly to a pre-programmed location, then slow way down to maybe 0.1"/sec for about an inch, then proceed quicker to a second location where another similar slow cut will be made, then return to home. The sled weighs between 20-30 lbs and rides on low friction UHMW PE slick strips between the sled and table saw. Roller bearings hold the sled in position using the miter slots on both sides (2 bearings/side). I will attach some photos of the sled below. The underside photo shows the slick strips (and miter strips which have since been replaced with roller bearings). I use the sled to cut out pieces for polyhedral puzzles in exotic woods - more photos below.
I don't think the stepper motor needs to be too powerful, but I think a moderate amount of power will be needed to provide smooth advancement of the sled. The bearings fit relatively tight so there is no play, and pushing the sled by hand can be a bit jerky after some cutting due both to minor amounts of sawdust contamination and fatigue after pushing it back and forth for a while.
Here's what I have planned so far, but not carved in stone:
Ball screw or linear stage with ball screw
motor drive that allows microstepping
I'd like to use Mach 3 and a PC to drive the linear actuator on the saw
Given the environment of sawdust - I think some type of sealed stage might be a good idea, but the cost seems much more for a stage. Any good ideas?
Really, I'm at the very beginnings of planning this out, so any advice will be useful - brand names, suppliers, know-how, tips, etc. I haven't built anything related to CNC before, but am interested to learn more.
Thanks in advance,