New Machine Build- gantry construction

[steve_p]

I plan to build a reasonably large (3m x 2m) moving-gantry router with quite a large z-axis (300mm or so travel hopefully), but I'm not yet sure how to approach making the gantry. I want to mount a 16hp ATC spindle I have bought already which weighs around 45kg, and I'm assuming a single box section, however big, probably won't be stiff enough over 2000mm. I'm wondering whether a pair (or more?) of welded aluminium or steel trusses would be a possibility? The finished space-frame could also be skinned in sheet to add to the stiffness (and to make it look less like a railway bridge!)

Anyone seen this approach used before?

[jcupido]

Take a look at my web site albertamachine.com there you will find a 15 foot gantry on a 45 foot table the truss section was cut out of 3/8" alum and bolted to the alum extr the cutting head travels @ 7'/second

[steve_p]

Originally Posted by jcupido Take a look at my web site albertamachine.com there you will find a 15 foot gantry on a 45 foot table the truss section was cut out of 3/8" alum and bolted to the alum extr the cutting head travels @ 7'/second

Thanks for that- I never thought about the trusses being profiled from plate rather than welded... a few of these with cross bracing to link them might be a good solution. Your sail cloth machine obviously doesn't deal with the same forces as a router, so it looks a bit lightweight with just the one truss for my application, but in principle looks good. Did you do any tests for deflection when there is force on the blade?

[jcupido]

this is a MK automation extrusion the truss was tested in the z axes .
The example has flex in the x axes or the untrussed axes .
I suggest you apply some engineering to the cut material with a dado or slotting to the fastening of the truss plates . If you wish to discuss this further please don’t hesitate to phone . Regards

[steve_p]

thanks jcupido

anyone else seen trusses used for a gantry?

[eloid]

Originally Posted by steve_p thanks jcupido anyone else seen trusses used for a gantry?

i was thinking of a simular idea as yours....

I was planing on using 8020 (1.5x3) or steel tubing as top and botton rail for the truss then cutting out a alum. truss as albertamachine.com then bolting the truss with the 8020 .. making 2 matched I beams gantry

and leave 6-8" apart spacing between beams then mounting some alum plate or members between truss making u shaped trough.

The cable carriers would run in the centre if the truss trough ... free up space ... also i was planing on use 4 linear rail on this gantry 2 front side 2 on rear of x gantry for unitizing the truss ( simular to the link)
allowing for 4 router to placed on this gantry ie 2 on front 2 on rear side....

It would be a hybrid truss & mechmate design.... of the gantry
the intent is to carry 4 heavy 5 kw vfd spindles.

note there would be no ball screw in gantry beam.... it would be r/p so the no obstical for echain cable carrier.



silmular to this link....
YouTube- CNC mach artcam