[ProjectCNC]

I'm planning on building a cnc router to cut a slot 0.028" to 0.043" wide thru 3/8" thick laminated maple. I have the mechanical abilities to build but need advise on servo size and ballscrew type. I'm looking to generate an accuracy of 0.005" within a 2ft sq. area. Also, I have a chance to get Indramat servos (pn 233778) (model# MAC093C-0-KS-3-C/110-A-0/s0001) for the xy axis. If anyone knows if these are good for my intentions please advise. Thank you.

[balsaman]

Not sure about the servos but thats a pretty thin slot. What is it for?

Eric

[ProjectCNC]

The slots are for inserting steel cutting blades. The wood acts as a base to hold the rule in the bent pattern. I found a source for bits this size but need advise as to what size servos I should use. I know slots this size can be routed, I'm just not familier with the force and speed necessary. Gerber Innovations makes a router just for this but it is out of my price range.

[balsaman]

I am thinking your feedrates required will be slow. You may need to do multiple passes. Look here for calculations for motors sizing.

http://www.cnczone.com/showthread.php?s=&threadid=1954

Eric

[ProjectCNC]

Thanks balsaman, GREAT link!
Darrell

[tsalaf]

If my memory has not faded, I believe the Gerber router uses V cutters with only the tip of the cutter shaped to cut a parallel sided slot the same thickness as the steel rule knife. This lets the cutter cut through 3/8" thick ply in a single pass, but the cutting speed is still fairly slow.

Steve

[ProjectCNC]

tsalaf,
You are correct, Gerber does use the v cutter but most of the bit is only the width of the rule (0.028",0.043"). I saw one in action at a trade show several years back but can't remember the feedrate. My plan is to buy several of these bits, mount in my milling machine, and find some way to measure the force needed to cut thru the wood. Any suggestions will be appreciated. I can then use the formula provided by "balsaman" to determine necessary servo size.
Darrell

[balsaman]

It's Mariss of geckodrive that provided the formula, I just pointed you to the link.

Eric