Brilliant Design 72"x36"x9" CNC Router (HobbyCNC based)

[vondeliusc]

Hi- My name is Christian.
I am announcing my >>>DIY CNC Router<<<
The link is my detailed blog regarding this build

Build: HobbyCNC-electronics based router.
Material: MDF 0.75"
Parts- cut out with table saw and post processed.
Design Basis: WoodworkerB's Blog
Actual size: 80" x 60" x 42"
Working size: 72" x 36" x 9"
CNC Design Tool: SolidWorks
Motors: 200oz-in 1.8 degree (200spr)
Lead Screws: 2-start 5tpi
Resolution: 0.001"
Machine Control: Mach3
Part design: SolidWorks exported as DXF
Plans will be available (someday, if there is interest)
Completion target date: 07/2011 (?)

I am a design engineer, I work in SolidWorks, I own and operate a PlasmaCAM CNC plasma torch (w Miller 375 Xtreme inverter 27a). I built the HobbyCNC chopper stepper driver kit, and have tested the motors with Mach3 and appears to operate nominally.
Feel free to get ideas for your own, or copy what I have done.
Visit my ongoing construction blog for this project and leave comments or whatever here.
Enjoy-
-Thanks
-Christian

[PaulRowntree]

Hi Christian;
That is quite a large machine! Are the sides of the gantry going to be MDF or metal? Either way, I would think that you are going to have some sway because of the height. Plus, the gantry sides become very narrow just below the Y stepper motor. Unless there is a very good reason for this, this looks like a weak point in the structure.
Good luck!

[vondeliusc]

Paul-
WoodworkerB's design did not allow the carriage to move past the gantry sides. So, as I designed, one of my criteria was to allow the gantry track to let the router bit center go to within ~1" of the sides of the table, to be able to reap the full width of the table. I know that this is a weak point, so I will use the CNC plasma cutter to create metal plates that will be mounted on the outsides with several bolts above and below to attach thru the gantry faces-kind of an exaggerated 'C' affair probably of 0.125"(?) Aluminum. And I wanted to have a fairly large table to be able to fabricate skins for the CriCri aircraft I am building.
There is also a 2nd y-axis stabilizing cross-member behind the gantry track that is not visible, which should reduce(?) Y wobble.
Thanks for the comment.
-Christian

[vondeliusc]

Hi Christian;
That is quite a large machine! Are the sides of the gantry going to be MDF or metal? Either way, I would think that you are going to have some sway because of the height. Plus, the gantry sides become very narrow just below the Y stepper motor. Unless there is a very good reason for this, this looks like a weak point in the structure.
Good luck!

BTW-MDF. And the size was driven by McMaster-Carr, because the ACME threaded rods come in 36 or 72" lengths; so, two 72"ers with one full for X and #2 cut in two for Y and Z. And dumpsterCNC anti backlash and couplers.
-Christian