I figure here is the best place to post this, as I don't think it would go over to well to start another thread on it.
Anyway, I'm the in-shop CNC Programmer/Operator trying to figure out how to use an ancient Thermwood CNC Router--No graphing functions, no direct loading of programs from the control software (all transfers have to be done in DOS Mode and then rebooting of the control software), and some rather unusual G-code settings (G53.x is the tool/part offset code?! There is no subroutine coding?!)to machine an unusual plastic material for the parts on this page:
A picture which will give you a general idea of what I'm making is in the top right corner of the page, and there is some technical data on the plastic material itself if you scroll down.
Anyway, the only discernible limitation I've run into is that the RPM speed must be a minimum of 1,800 RPM but no more than 20,000 RPM--Table feed rates can range from 1-1,000 inches per minute, though I've never taken it above 300 because of the resulting vibration from the motors making me quite nervous about it maintaining any degree of precision in it's movements.
My current dilemma: I'm having to cut about 156 "herringbone" pattern slots in a single part with a 1/2" diameter carbide end mill (30 degree helix, 2" length of cut and 4" overall length of the tool, with about 3" of it hanging out of the spindle in order to avoid crashing into the monstrous clamping system I'm forced to use) at about 1.250" depth per slot, those of you reading this who work with similar machines can probably guess at what kind of problems I'm running into in terms of tool vibration at higher speeds... but the best I can come up with is about 3,000 RPM/36 Inches per minute.
Which is, of course, unacceptable in terms of production time as the order calls for 7 of these parts, and our ever-zealous sales staff agreed to a deadline of October 6 for the shipment.
So... can anyone here offer any suggestions in terms of alternative tooling for this problem?
Also, are there any freeware programs out there that can convert an AutoCAD drawing to NC Code automatically?
I'm wasting inordinate amounts of time programming these things in notepad and copying them directly into the hard-drive of this CNC machine, testing the program without tooling or on scrap material to make sure I haven't made any errors in these several hundred line programs.