[dedeer]

Hi,
I am building a new CNC router for cutting wood and at the moment i am at the designing stage. I already have some 35mm Rexroth linear rails for the X and Y axis which i plan on using . The rails dictate the dimensions of the machine which will be about 1300mm wide and about 1000mm long . The Z axis travel will be about 200mm . I have 4 rails and i only have 4 carriages so that means a carriage for each rail. These are big carriages almost 100mm long .
As you can see from the pictures i was thinking on using the rails for the gantry in this L configuration because of the weight of the rails ,each one weighs about 10kg, this way the weight is more evenly spread across the Y axis carriage.

Will this configuration be less stiff and more prone to twisting than the usual configuration where the rails are on the same face of the extrusion and the extrusion is double the height ?

[dedeer]

I designed the z-axis so you can see how it all fits together. Between the carriages is were i plan on mounting the driving screw. The actual extrusion for the gantry will be the one from the pictures i posted above.

Attachment 351666

[dedeer]

I went along and finished another project i had going on based on the same principle only smaller and it works OK so far . I still need to get a bigger, better spindle and try it but i am confident it will be fine. I strengthened the gantry by bolting a 15mm aluminum plate on the underneath of the extrusion.

Attachment 358146
Attachment 358148

[awerby]

The same principle? It looks like your first design is for a moving gantry, but the second one has a fixed bridge and moving table. Both will work okay, but they are different. What's your question?

[dedeer]

I see you did not read my first post. The gantry linear rails configuration is the same as the bigger mashine, thats what i meant.

[ger21]

Will this configuration be less stiff and more prone to twisting than the usual configuration where the rails are on the same face of the extrusion and the extrusion is double the height ?

Yes, the bigger the gantry beam, the stiffer it will be. Rail location has no effect on stiffness.

[dedeer]

OK. Thank you for answering .