New DYI Fixed Gantry Router Build

[DonFrambach]

I'm about to start building a small fixed gantry router. I plan to make complex carvings in wood (and hopefully aluminum) using models prepared by Vectric Aspire.

I've attached drawings of my anticipated build. Comments (especially those pointing out design flaws will be greatly appreciated). I plan to make most of the components from 8020 extrusions and connectors. A small amount of steel plate will be used. I plan to use rails and blocks for the X axis obtained from Glacern. The Y and Z sliders will be made using components from CNCRouterParts.com.

I will add corner gussets and plates for rigidity that are not shown in the drawings.

[DonFrambach]

Another drawing. The X-axis lengthened a little. More details added. Did not add plates to the drawing because they would obsure construction details.
Comments?

[DeadTom]

Looks good so far, start collecting the needed parts and keep the pictures coming.
DT

[DonFrambach]

Construction has begun! I expect it to take some time. Comments will be greatly appreciated.

[RomanLini]

Looks nice! I saw your orig cad drawings before when you posted the thread.

Are you going with the design in post #2? If so it might be best to turn the 2 inside base cross rails to vertical, to give 4 support places for the rails (not just the 2 rail ends).

I also think it would be good to add a base plate either above or below the base area to reduce flex there, my preference would be above as it will also be cleaner for stopping chips that would fall down and fill up your base structure.

And one thing that's always worth thinking about is to re-examine how much vertical travel you actually need. With a moving table build only the Z axis is mounted on another axis so its the only axis with multiplied slop, so by reducing Z travel and spacing the Z bearing further apart vertically, you increase total ridgidity a lot. On my littl emoving table machine i limited the Z travel to 60mm and the gantry clearance to 60mm (for better rigidity) and have never regretted it.

[DonFrambach]

Some more progress. Removed gantry (for now). Added corner braces to base. Also assembled base with longer screws (not shown were 5/8" now 1"). Added support for x-axis. One rail placed on support. Not screwed down yet.

[DonFrambach]

Assembled Z axis per plans from CNCRouterParts.com. Also got Mach 3 running on an old PC and connected to a Gecko G540 and 3 steppers. Works real well. Under no load, there is no measureable backlash with my cheap Grizzley dial indicator. Electronics still need to be encased. Thinking about a Smooth Stepper too.

Will probably reduce Z travel in future. Without reducing travel, the assembly can be shortened by about 2 inches.

[DeadTom]

Your making good progress Don; what size are your steppers?

Tom

[DonFrambach]

Originally Posted by DeadTom what size are your steppers? Tom

NEMA 23, 380 oz-in steppers purchased from CNCRouterParts.com

Don

[DeadTom]

Don,
I am running the a HobbyCNC Pro board with 200 oz-in steppers, they are pushing around a modified JGRO (mdf=heavy) machine with a Sears Craftsman 2.5hp router. Works pretty darn good, could be just a little faster though as I am running single start 5/8" 11tpi all-thread on all of my axis. I can run at a respectable 30-40ipm, I can push it but I don't want to break anything until I finish my upcoming all-metal machine.
So, your steppers will probably drive your bits and/or spindle right through the bottom of your table so be careful , jk.
But you do have alot of power for such a small cutting area.......awesome.
Tom

[cncbob]

I like the look of your machine, seems very sturdy. One day I think I may build one out of extrusions as well.

[DonFrambach]

A little more progress. Finished mounting the X-axis rails to their supports. Beginning to add support plates. My teasing wife keeps telling me that I didn't have enough tinker toys when I was a kid and I'm making up for that now. I'm a little concerned that the gantry may be too tall as pointed out by RomanLini. Some photos: