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View Full Version : Need to build a 4'x8' CNC router fast!



robertmonroe
11-24-2008, 07:52 PM
I need to build a 4'x8' CNC router fast and money is tight. Baascically I am vacuum forming 4'x8' sheets of 1/8 th inch ABS and I want to trim and drill on the CNC.

Can someone tell me the approximate cost of building a 4'x8' Joe CNC.

Is there a 4'x8' kit available?

Thanks in advance for any helpful responses.

Robert

bp092
11-25-2008, 06:40 AM
No 4x8 yet just 4x4 and there is a kit for it. What's your budget like?

robertmonroe
11-25-2008, 11:33 AM
The budget is 2-4 thousand over two months. Probably going to build a mechmate.

Glidergider
11-26-2008, 12:44 AM
I've seen both sets of plans, and Joe's Hybrid plans a better. But if you need a 4x8, then you are pretty much out of luck.

I know Joe is really busy, but I hope someday he will stretch his design into a 4x8. Yes it would require going to a rack and pinion drive system. That would add cost to the build. But some of us would go for it.

I wonder if it's possible to build a mechmate within your budget. I have doubts.

High Seas
11-26-2008, 01:12 AM
Search for ninegwt- aka inshoreboats. He has one CADCut I believe -- may pull off the 2-4K but that might be less the electronics!

Is the FAST also the 2-4 months - or is that just the budget cycle?

Kahlid built his in 10days! Fairly sizeable as I recollect but may not be 4x8.
:cheers: Jim

bp092
11-26-2008, 07:05 AM
Yeah a 4x8 isn't feasible with a 1/2" ball screw there would be too much whipping. In the future it would have to be a larger diam. ballscrew but optimally a rack and pinion setup with geared oriental motors.

The mechmate is a heck of a machine, and if you have the resources to build one its the ultimate machine. But I too have doubts you could build one for that budget; you probably would have barely enough to just build the machine electronics/motors aside. But others might a better answer to that.

joecnc2006
11-26-2008, 08:28 AM
The MechMate sure is a heck of a machine, But sometimes a little above the simple DIY guy in the garage without a workshop, so thats why i did the CNC4x4 Hybrid machine, I think the MechMate will cost between 5,000 to 6,000 for people to build when all said and done, the cost adds up.

It is possible to build the 4x4 into a 4x8,with mods, i just have not done it yet, but do have plans to build a 4x8 maybe this comming year, which will be just slightly different from the CNC 4x4 Hybrid, Its all in my head still, Just need to try to shake them out.

Joe

Paulds
11-26-2008, 11:34 PM
Hey guy just a thought on the lead screw whip issue.I've been mulling this arround in my head for a while and thought i'd throw it out here and see what you all think.
Here is the idea have a piece of 80x20 extruded aluminum 1.5"wide3"tall say 10'' longer than needed.Have your lead screw mounted in the usual way with a delrin nut, ball screw what ever. Now mount a sleave assy.that goes arround the acme rod(that does not capture the threads) that will fit in the t-slot of the 80x20 using the T-Slot as sortof a slide.Now on the back side away from the lead screw nut put a spring that will compress when the ball screw pushes against the sleave. Do this on both end say where the spring will come out say 20" to 30" this would take care of any whip.You could even come up with something that would attach to the lead screw nut using the same principle.This setup may take away from the steppers some but everything has it's trade offs, may just a little slow in speed but for double the size in table length well you get the idea.

ger21
11-27-2008, 07:28 AM
You could just use 3/4" or 1" acme, but you'll need stronger motors to overcome the increased inertia.

stoneyreef
11-27-2008, 10:10 AM
You don't think the 570 oz motors could overcome the inertia of a 3/4" screw to give 2 extra feet?

As I posted earlier the 80/20 is only $10 more for the next size up. so that would give one a 4X6 machine.