Hello everyone! Lets jump into it... My boss had a K40 chilling in a closet at work and said I could have it.(Score!) I consumed all the content I could find and got to work doing the usual mods. I've installed a Cohesion Laserboard, 3D printed an air assist nozzle and a few other parts, exhaust, etc. Now I want to rebuild the whole gantry similar to the one by tshilling on here. My current plan is to just scoot the divider and power supply over a bit rather than moving the electronics to a new enclosure. This gives me about 650mm in width to work with.(a little more if I mount the power supply on its side) I've never done a project like this so I really don't know if my current mock up (not complete) is totally stupid and impractical. I'm learning as I go and its exciting, but also kinda overwhelming. So I'll explain where I'm at and my thought process, and you can tell me if I'm doing it wrong. I salvaged some N17 steppers from my old Printr bot, they seems to be similar in specs to the OpenBuilds ones. I connected one to the Z axis on the Laserboard and it works fine. Some reading I did explained I'll have to adjust some settings in Smoothie for the higher amps(not quite at the stage so I didn't read too much about it) I like the design of the belts running through the 2040, so I ran with that design. I wanted to do dual motors for the Y axis. I mounted them facing the same way so they can run in parallel and I assume easier to wire up. The X axis motor is mounted in a way that feels backwards to me, but it gives me more clearance from the back of the case. I know I can plug the steppers into the Laser board either way and they will spin CW or CCW so It should be fine..? I guess currently my main questions are based around the "transmission". Is the current motor layout practical or am I doing this all wrong? What belt and pulley sizes should I use? I really seem to be struggling to understand the different options, what effect they will have on the movement, and if I will need to make other adjustments in smoothie for them. I appreciate any input, but please phrase it like you're talking to a 5 year old so I can understand! Thanks!
Dual Y motors are dangerous. Use a driveshaft to sync the sides. If it goes skew, or out of sync, the mirrors on the gantry now point the beam past the next mirror, missing intended target, wildly aiming at the nearest combustible material or eyeball. Flying optics means alignment security is critical
Ok, thank you! I went back and forth between the two designs but somehow the dual motor was less confusing to me. I was having trouble on the assembly of the shaft. If you don't mind helping me out there. Would it be a pulley and coupler mounted on the nema shaft > 5mm rod?>another pulley>threaded rod plate with bearing and thats all? Or plate with bearing>pulley on the end Sorry, I'm new to all of these components and I don't really know what parts go where yet.
Ok, I think I'm learning. Would this be a practical way of doing the Y? 5mm-8mm Coupler>8mm threaded>3GT x2>plate with bearing. My only issue here is I'd have to offset the motor to have the pulley line up with the rail. Easy enough to fix with a 3D printed spacer or maybe a spare piece of extrusion. Thoughts?
Better, but two suggestions: Motor > Coupler 5to8mm > Bearing in a plate > GT2 Pulley > rest of shaft (8mm roundbar) can whip so maybe some bearing+plate support in the middle > GT2 pulley > Bearing in a plate (extra bearing on left side as belt tension pulls on pulley axially, but no bearing there to support it (as bearing on motor is on other side of a flexible coupling, plus you shouldnt really load up a motor bearing either) The other being threaded rod is <8mm so the pulleys, shaft coupler, etc will not sit well on them - with a too small diameter rod, they will sit off-center. Use a piece of 8mm 304 Stainless round bar (easy to get from most metal suppliers, no need for hardened/chromed etc, good old 304 stainless will do, and tend to be pretty close to exact 8mm (check with vernier while you buy)
openBuilds FreeBURN-2-Mini V-slot CO2 Laser (40-50w) checkout this post - that's how I did almost the same stackup for Freeburn2 To get around the offset motor I used another pulley and short closed-loop belt, might have some inspiration in that
What do you think about a dual shaft stepper mounted in the center? Would certainly save some space on the sides. They don't seem to be very common though, which makes me think they may be a less desirable choice. Thanks!
