[groomden]

just started to design an 80/20 design and would like feedback on the design so far. Thanks!

http://www.flickr.com/photos/dgroom/3033283524/sizes/o/

If anyone can tell me how to post pictures directly to this site or where/how to post the SketchUp file i would be glad to send that out too.

I've already ordered all the 80/20 that I can afford right now... so the long side can only be 39inches, obviously with a smaller cutting area than that.

I designed in the linear bearings and stuff from CNCRouterParts. One question that I have in particular is will my design with a linear bearing and a motor mount on top of each other work in practice or do I need more clearance? Actually, it sure seems like this is a part that CNCRouterParts should offer as a single piece of machined aluminum.

[ger21]

If anyone can tell me how to post pictures directly to this site or where/how to post the SketchUp file i would be glad to send that out too.

Click the Go Advanced button, and then find the manage attachments button. To post a Sketchup file, you'll probably need to zip it first.

[groomden]

Take a look -- feedback really wanted.

Thanks

[FandZ]

Thanks for posting your Sketchup file. It's so much nicer when you can rotate an item and study. I don't understand your Z axis. I'm guessing you are still working on it.

Your upper green X axis, I wonder if perhaps it should be reinforced. With that length, I'd be afraid of some up and down flex towards the middle. Do they call that chatter?

Your Y axis, You could mount your rail on both sides like you have your z axis. Just to give it a little more stability.


You could also move your leggs to the inside, to save a little floor space. 80/20 seems to be the way to go. It's looking like it will be one lean, mean, cnc cutting machine. Thanks for posting.

[ger21]

Didn't look at the Sketchup model, but in the pic you linked to, I'd get rid of the green parts and go with the more conventional dual driven gantry. The overhead parts are going to restrict your table access. And you may find that the center mounted screw allows some racking while cutting near the ends of the gantry.

Also, where is the table surface going to be? At the bottom of the legs? If so, you need a solid base, and how will you mount the machine to it?

[groomden]

Thanks for the responses.

Z axis is not shown FandZ, The purple piece is a placeholder to where I will bolt the Z into.

Ger21 -- Yes, the table will be at the bottom of the legs, with the idea that I can route parts of a semi-infinite length by moving the machine/or piece. I'm seriously thinking about a dual axis X design, the additional cost is the only thing making me 'force' the overhead x-drive. I plan to bolt the machine to a sheet of mdf or something. I have no plans except for fun with the machine, so absolute tolerances aren't too important to me. As long as I can mill replacement parts out of titanium for the space shuttle that is

[FandZ]

As long as I can mill replacement parts out of titanium for the space shuttle that is

Whenever a coworker see's me working on my plans at work and asks me what do you need one of those for, I tell the to build a space ship you dummy...lol

[groomden]

more feedback appreciated!

better?
http://www.flickr.com/photos/dgroom/3044963898/sizes/o/

no z-axis shown.

[FandZ]

Looking good. I've read somewhere, though, that your Y axis should be twice as long as your x axis. I don't know why. But if you look around most cnc's are like that.

Also for you y axis, look at page two of this build. http://www.cnczone.com/forums/showth...=517368&page=2 I think the use of one vertical rail would be better. Less for you to drill and easier to mount.