4x8 CNC Machine

Creator:
EnabrinTain
Status:
THIS TOOL HAS BEEN RETIRED SEE REPLACEMENT NOTE
Born On:
15:47, 22 March 2012 (CDT)
Last Updated:
23:59, 17 November 2015 (CDT)

REPLACEMENT NOTE

This cnc has been replaced by the ACCTECH 4'x8' CNC

Overview

This is the project page of a CNC capable of milling 4' x 8' plywood sheets. I bought a 52" x 104" (area) Plasma cutting table from eagleplasma.

Future Improvements:

increase cut stability with a more rigid gantry that maintains at least 3 and preferably 4 points of contact on the X and Y rails. Currently the X rail only has 2 points of contact and so z plunge rate is adversely effected.

CNC Control Software

I'm using Mach3 to feed GCode to the controller, it seems to work well. Future experiments in the pipeline include upgrading the computer and experimenting with CNCLinux. CAM Software has been a problem for us recently:

LazyCam(we have a license) - does ok for most dxf features but can't handle curves. has good tool diameter compensation.
InkScape(open) - has a plugin to export GCode, I haven't had much luck configuring the tool diameter preferences.
PyCam (open) - I haven't had much luck configuring the tool diameter preferences.
CamBam (free version) - Tyler's been experimenting with it, the experiments look promising.
MakerCam - Tyler and Raymond have had reasonable success using this tool.

Other Resources

Feed Rate Calculator

Status

10or11 May 12: Ordered CNC Kit from eagleplasma.com
16 May 12: Kit arrived in 3 boxes (145#, 145#, 95#) - I like to call them Huey, Duey, and Louie
17 May 12: Uncrated the contents. (see below for pictures)
18 May 12: ASSEMBLY
28 May 12: Built Spindle Mount
30 May 12: Calibration
13 Jun 12: First cut: X-Axis had trouble with belt jamming; upped the Amperage to 100%-->20%; Need to play around with one of the pulleys to see if i can keep it from pinching the belt. Opinion: This would not be a problem if I were plasma cutting. The router is adding resistance that the stepper is having trouble adapting to. Worst case scenario: I replace the current NEMA23 stepper with a spare NEMA34 that was used in the old cnc..
27 Dec 12: After a couple of months of not really understanding what was going on, I decided to replace the belts with #25 chain. The Blackfoot CNC uses this system for their systems. It seems to have solved the problems for the x.
Middle of Jan 13: Replaced Y axis belt with chain. Hardware seems to be good.
13 Apr 13: Replaced cog on the X axis motor due to the tightening screw hole being stripped out resulting in slippage. Everything working beautifully again.

Links to Cuttable Pattern Resources

Links to CNC Machine Resources

A small company building hobby plasma cncs
Contraptor
flexible manufacturing system
Build Your CNC (a distant relative of the 2x4 CNC Machine) *closed source
Mechmate *closed source
neo7 cnc
80/20 Ebay store

Assembly Pics

Crate Contents

The crates arrived! the vertical one weighed 95lbs, and the two horizontal ones were 140lbs!	The Gantry box without its cardboard. see the dalek in the background?	The contents of the gantry crate.	The cnc table crate, marked 'bottom'
The cnc table crate contents, marked 'bottom'	The cnc table crate, marked 'top'	The cnc table crate contents, marked 'top'