Hey folks, I've assembled small CNC machines and 3D printers from kits, and I'm happy with the coding side of things, but hardware remains a mystery to me so I'm hoping you can help! I want to build an ASRS (Automated Storage and Retrieval System) for my home workshop. Not because I particularly need one, it just seems like a cool thing to do! At the moment, my plan is to use a belt-drive for the X axis, and something like this setup for the "Y" Axis, but I'm not sure if I should be looking at belts or screws for the Z axis given that it could end up being 1000mm in height. I'm also wondering if I'd need to "stabilise" the top of the screw if I did go down that route, I'm assuming that I would, but I can't really find a proper answer anywhere online. I know I'm going to have a lot more questions as I go through this, and I thank you all in advance for your patience and knowledge that you share!
Depends on the weight of the item. For heavier items screws are best as you don't want the carriage to go into free fall should a power outage occur depriving the motor of holding torque. That's not to say this is not also possible with screws but it is less likely as detent torque will generally hold a screw in place. The problem with free fall is it turns your stepper motors into generators sending electrical charges back into your electronics. If you're looking at any significant length at all, yes. You could also put the motor at the top, hanging the load. This will also help stabilize the screw, but again with any significant length you'll need to stabilize the opposite end.
ok, thanks - in this case the "pallets" will be plastic containers with various electronic components in them, but as they might range from a resistor through to NEMA17 motors, the weight is definitely a factor. I'll look into the screw options instead.
The comment about hanging the screw rather than having it "pointing up" made me think about a gantry design. As a rough idea, I assume you mean something like this: It's a rubbish diagram I know, but the best I could do in OpenSCAD with the time I had available. Is there a particular distance over which securing the ends of the screws becomes necessary, or is it a "that looks a bit wobbly, I should probably do something about that" moment?
It'll be easier just to work with stock actuators V-Slot® NEMA 17 Linear Actuator Bundle (Lead Screw) - OpenBuilds Part Store, built into a framework. Rough concept shown below. Sketchup file attached.
