Hi I have been lurking about for quite a while now researching, admiring, what a wonderful site. I have kinda reached my limits with the manual cutting so the CNC addiction is taking hold.:cool:
What I am looking for is a few pointers/ thoughts on the following design problems.
Planning to build a small (and cheap:rolleyes: I live in rip off britain) plasma table (4' x 2' working area) look at meincer's portable table for the basic construction idea, mostly steel frame probably a piece of alu section for the bridge to save weight. I am very short of space so if it can be stored away while not in use then so much the better. Was originally planning to have the gantry 4' (working) wide will this make the machine unstable? with only 2' travel, should i flip it round?
The Idea being that the torch can cut below the base of the frame so when working on large sheets (should I ever need to) the "table" is clamped /fixed to the sheet itself, is this a silly idea for some reason?
Can always make a seperate table/ or water tray in the future should I need to, and fix the frame to it.
Edging towards belt drive as its quieter, seems smoother, (see fiero addictions lovely table) no screw whip problems. are screw whip problems existant on this size table?
motors/drivers etc will be a kit something like this??http://www.motioncontrolproducts.co.uk/product_info.php?cPath=5&products_id=9.
Looks like Mach 3 sheetCAM and a Cad package are the order of the day. Am familiar with photoshop not sure if I can use this in some way (more research needed) may get a CAD program to play with and post some design pics. !!! all sketches / hand drawn at the moment.
TORCH issues. I have a small 40A plasma cutter with a contact arc type tip ( possibly called a drag tip) can I use this have not the funds for a new plasma cutter. can I program Mach 3 to start the cutter in contact with the sheet then raise it about 1 mm to cut. Also have an issue with piercing with the torch, Manually i either hold the torch at an angle and then bring it up to perpendicular (further complicates the CNC) or I drill a hole and start the cut from the edge (much preferred for neatness of cut) or can I adapt purchase/ another torch for the plasma cutter. If not can I get Mach 3 to do a dry run before cutting, mark the holes then I can drill them? later I could even add a small drill head..:idea:. now we are getting silly
Am worried that the plasma torch may fry the electronics not sure I understand the Isolating/grounding problems that people have expirienced.
Will be cutting upto 3mm mild steel for practical and decorative pieces hobby use. maybe to sell a few bits to recoup some of the cost.
And Finally just to complicate matters (as if it wasnt complicated enough) would quite like to swap the torch for a router . will this give the belt drive problems from a driving point of view also what about dust?. (NOT talking about a huge router with a 13 (1/2") mm bit and just some decorative stuff) and will not be looking for quick turnaround between heads. Does Mach 3 work on routers and does this mean I need 3D CAD.

Thanks in advance and keep up the good work on this great site.
:cheers:

A small moveable table is a novel idea! I like it! I am building a higher definition table right now and am quickly finding out how heavy a gantry can get. I think my gantry will weigh in at 300lbs...I may have to change some things as I will be using TC's 4 axis servo setup from candcnc.com

WOW! 300 lbs. Sling that around at 400 IPM and reverse direction then calculate the foot pounds of energy (:-o. The dual drive servos will do it (as long as your pinion teeth can handle it!). They do need proper gearing to get the torque.

TOM CAUDLE
www.CandCNC.com

Yep Tom I may do some different rails. I will be using the 10-1 belt setup blocks but I am worried about belt stretch and accuracy with the long axis. My rails are VERY large and 92 inches long so I am was going to build a 92" by 130" machine and may have to downsize. :cheers: