AndyUK's Build - 1.2x1.0m Gantry

[AndyUK]

Thanks Neale, that was a super helpful post, and its going to take me a few evenings to reply in full!

Lets talk numbers first, because I've being doing these calcs behind the scenes. I've written my own version of irving2008's motor calc sheet. Its basicly the same, but I'm doing the calcs myself so I understand it, and I'm doing all three axis at once. I've also modified it to cope with dual screws on the X (I've doubled the screw inertia then doubled the Est Torque output - which in my head counters the additional drag of driving an extra screw against the additional power output.)

I've set the sheet up here for 5500mm/min, with a 50N (Ali) cutting force. Its currently not setup for gearing at all - and I have a microstepping factor of 1x because I haven't thought how to include these factors yet.



So, with 2x 4.0 Nm on the X we can just achieve this setup (I say just - as per the original spreadsheet there's a 3x Margin on the required torque), and rapids at 9000mm/min whilst staying below 900rpm (below corner and 80% of critical speeds). Note that although I've simulated 3.1 Nm on the Y and Z, they're massively overkill. Especially the Z.

Questions are - does this look realistic and okay? Is my dual screw fudge acceptable or are there any obvious holes?

Any tips on how to integrate the pulley factor and microstepping? How do I take these results and figure out what gearing to use?

Thanks!