Build Log: 3-4 Axis Mill/Router

[JAZZCNC]

What about the linear guide width, 25mm OK? Bearing distance, there's about 105mm between the ends at the moment. Would you recommend at least doubling that?

when you say 25mm I suppose you mean Rail not carriage width.? If so then yes that will be fine if your using supported round rail but massive overkill if using profiled rails like Hi-wins. 20mm will be fine for profiled, even 15mm will handle far more load than you'll throw at them but 20mm carriages workout easier to use has they larger and suit better.

To be honest the Min/MAX distance for separation on Y axis( Which I call Z axis) will depend on several factors like number and location of ball-screws and rail used. 300mm total bearing plate width will be fine in most cases and less if using profiled rail and twin screws close to the bearings. 200mm will even work if the gantrys strong.

Regards the gantry then you need to seriously beef up this area with bracing. I'd also use wider stronger Cross beams between gantry sides.

Skinning is ok for containing chips and looks etc but wouldn't rely on it for strength and the down side being it's very resonant and you want to avoid resonance if possible.
Stronger base frame work is the best way then skin for cosmetic reason if you feel the need.!

[IanS1]

when you say 25mm I suppose you mean Rail not carriage width.? If so then yes that will be fine if your using supported round rail but massive overkill if using profiled rails like Hi-wins. 20mm will be fine for profiled, even 15mm will handle far more load than you'll throw at them but 20mm carriages workout easier to use has they larger and suit better.

To be honest the Min/MAX distance for separation on Y axis( Which I call Z axis) will depend on several factors like number and location of ball-screws and rail used. 300mm total bearing plate width will be fine in most cases and less if using profiled rail and twin screws close to the bearings. 200mm will even work if the gantrys strong.

Regards the gantry then you need to seriously beef up this area with bracing. I'd also use wider stronger Cross beams between gantry sides.

Skinning is ok for containing chips and looks etc but wouldn't rely on it for strength and the down side being it's very resonant and you want to avoid resonance if possible.
Stronger base frame work is the best way then skin for cosmetic reason if you feel the need.!

Yes, 25mm profiled rail. I'll look at 20mm instead. When you say twin screws, do you mean one either side? If yes, that is my intention, driven by a single motor using pulleys and belts.

Yes, the gantry need some serious beefing up and is in no way finished in the drawing. I'll do some more work on it and post again.

With regards to the resonance, I know some folks have used kiln dried sand to fill the box section but has anyone used sound deading materials stuck to the back of the skinning to help with resonance control? I have some sheets of a bitumen based damping mats which work very well for killing resonance. More info here: Bitumen Based Damping Mats [01] - £0.00 : SoundProofing Services, Sound Insulation, Acoustic Insulation, Acoustic Foam, Acoustic Panels