[ger21]

I've finally got some parts assembled for my gantry router. Basically have complete y-axis and z-axis without the motors and leadscrews. Z-axis uses 3/4" shafts with linear bearings, Y-axis uses rollerblade bearings on 2" EMT conduit mounted to a baltic birch torsion box gantry rail, which is extremely rigid. X-axis will be similar to Y. Overall size will be about 40" Y and 60" X. Working area should be about 48" x 30", with a 5" Z clearance and about 7"+ of Z-axis travel. Router to be Porter Cable variable speed 690. Here is an overall view.


Gerry

[ger21]

View of Rollerblade bearings, mounted to 1/4" thick, 1-1/4" x 1-1/4" aluminum angle, spacers cut from 1/4" brass pipe

[ger21]

Close up of mounted bearings.

[ger21]

I glued a 1/4" aluminum plate to 1/2" plywood to stiffen the top and bottom plates, also to draw heat from the motor. Here's a view showing the motor mounting location, as well as the linear bearings in the Z-axis.

Gerry

[toolsalot]

:banana: Nice job on the frame work. It must of took a long time to cut all those wood pieces out by hand.

[ger21]

Actually, I cut them all on our cnc at work. I'm going to take it all apart and drill a lot of holes tolighten it up, as it's a bit heavier than I'd like. But it is very solid.

Gerry

[balsaman]

looks great! I like the 2" emt.

Eric

[ezland00]

Where is the lead srew

[ger21]

It'll be between the z-axis shafts.

Gerry

[Mr.Chips]

Could you post a pictur of your your X axis rails and bearings. Interested in seeing how you mounted them.
Thanks
Hager

[ger21]

I Haven't assembled it yet, but the parts are all cut and waiting. I had to put everything on hold for a few months. Basically the X-axis is the same as the y, just larger. I'll have threaded rod through the Y axis tubing to keep everything tight to the X-axis tubing, as well as threaded rod under the table to keep everything tight there, too. The table will be suspended from the 2 ends. It's a torsion box, with the inside framework from 3/4" baltic birch plywood with 1/2" baltic birch skins. I'm hoping this is stiff enough, as I havent assemble it yet. The Y-axis shown in the pictures will also have skins attached to both sides, to stiffen it up. For information on torsion box construction, look here:

http://www.diynetwork.com/diy/shows_..._26946,00.html

Gerry

[Max]

Gerry,
I looked at the layout of the torsion box table and the first thing that popped in my mind is that it would make a great "zoned" vacuum table because of all the individual boxed compartments.
hmmmm, not bad
Thanks for the link. I hadn't seen that site before

[Mr.Chips]

Gerry,
Integrating the features of Torsion design will make your CNC a rigid and light machine. And CNC cutting the grid to fit the tubes then bolting everything together completes the torsion sides, good planning and design. Wish I had access to a CNC to cut my material out. I'm guessing that the tubes were mortised into the gantry sides also.
One of my hobbies is woodworking and I am building out of 3/4" MDF. Going for rigidity, but I’m taking the brute force method. The gantry sides are two 3/4" layers and have mortised the gantry cross piece which is also two 3/4" layers into the inside layer of the gantry sides. Everything was glued and clamped together. Because of the mortising the gantry is quite rigid. However at the sacrifice of weight. It weighs a ton.
My objective with this first machine was to make a machine that would accurately cut out my second machine, which before reading your posting was going to be aluminum. But now your design has stirred my interest in "Torsion" construction methods.
Keep us posted on your progress, interested to see it complete and running.
Hager

[ger21]

Hager, with a few jigs, my parts could have been easily cut with a table saw and drill press. As for light weight, I way overbuilt it and it's actually quite heavy. Before I put it back together I'm going to be drilling a lot of holes to lighten it up. But the weight shouldn't be a problem, as I'm driving the gantry with 2 250oz-in steppers.

Gerry

[Mr.Chips]

Gerry,
2, 250 oz-in steppers should do the job.

Excuse my I'm a newbie and gotta ask. I suppose you will be driving on each rail. What is the likelyhood of loosing steps of one motor, and causing the gantry to bind?

Does the one driver module drive both steppers on that axis?

Hager

[ger21]

From everything I've read, you only lose steps if you try to go faster than the system is capable of going. If you set up your software correctly, and stay within the machine's limits, you shouldn't lose steps. Ive got a Xylotex 3-axis board + a single axis board. I'll probably use the single axis board for my z-axis, and the 3-axis for the 2 x motors and the y-axis. All the motors are 250 oz-in. Z-axis leadscrew is 1/2-10 acme, X and Y will be 2 start, 1/2-8 acme (4 turns per inch). Hopefully I'll be able to get pretty good speed out of this setup. I'm hoping to be able to cut at at least 50 in/min.

Gerry

[vacpress]

gerry


its been.. 5 months since this post - updates? hows the build? im curious how the torsion box worked out, as i imagined something like that a long time ago... it reminds me of the bucks ive built to make shaped plywood furniture...

pictures?

[Bloy2004]

Originally posted by vacpress
gerry


its been.. 5 months since this post - updates?
pictures?

I feel the same way...have been waiting more info!

[ger21]

Hopefully I'll be back to work on it by June, maybe sooner. Just have to finish the kitchen.

[Bloy2004]

....upload pictures of your kitchen!