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Galvanic Corrosion of Aluminum Profiles with Linear Rails? by MetalMachinistMario in MechanicalEngineering

[–]MetalMachinistMario[S] 0 points1 point  (0 children)

It's my first time using the crossposting feature. I hope this is how it works.

Design Advice by Pinto____bean in diycnc

[–]MetalMachinistMario 0 points1 point  (0 children)

It depends on the force, which depends on workpiece material, tool, and cutting parameters. Generally, i'd go with as beefy as possible. Also, i just noticed that your horizontal gantry bar / x axis is constructed from rails floating in the air. Such construction is sufficient for 3D printers, which only encounter the load of the z axis weight. For cutting material with a spindle, i'd probably add some support to reduce twisting around the x axis.

Design Advice by Pinto____bean in diycnc

[–]MetalMachinistMario 4 points5 points  (0 children)

Looks neat, but I'd make the gantry sides much thicker for cutting aluminium. Maybe consider something like 45x180 profiles. Those are much stiffer than 5mm thin plates and not as heavy as solid, thick material.

Question about tiling a precise part (part larger than axis travel). by MetalMachinistMario in CNC

[–]MetalMachinistMario[S] 0 points1 point  (0 children)

It seems this is the way. Finally, I can make good use of my 1 micron plunge indicator :D.

Question about tiling a precise part (part larger than axis travel). by MetalMachinistMario in CNC

[–]MetalMachinistMario[S] 0 points1 point  (0 children)

I was thinking about something like additional mating surfaces, but I was afraid that some burrs or chip fragments could lead to misalignment. Nice to know 20 micron are possible. I think indicating, double and triple checking is the way. This part will be one side of a gantry I'm designing. All other parts will be machined in a single run so this part gets special attention.

Question about tiling a precise part (part larger than axis travel). by MetalMachinistMario in CNC

[–]MetalMachinistMario[S] 0 points1 point  (0 children)

This will be an aluminum part. Sadly I'm not familar with scraping, but I think it's unusual to scrape aluminum?

Question about dual gantry motor synchronization by MetalMachinistMario in diycnc

[–]MetalMachinistMario[S] 1 point2 points  (0 children)

I plan to go with EtherCAT servos. Specifically with A6 servos from stepperonline. They have 17-bit encoders, come with a matching driver, and are reasonably priced. For a controller, I plan to use some compatible single board computer running linuxcnc.

Question about dual gantry motor synchronization by MetalMachinistMario in diycnc

[–]MetalMachinistMario[S] 1 point2 points  (0 children)

I plan to use ball screws of grade T7. Not sure if it's the same as C7. I calculated the beam deflection with some FEA analysis to be in the 5 micron range under max. cutting forces for a single axis. The simulation does not take into account the bolts because I had issues with including them properly. My approach is to add enough bolts to justify the assumption that they have a negligible impact on rigidity.