I want some input from the community, especially those with knowledge on the subject, concerning the possibility of utilizing alternative means to achieve movement of the Z axis.
Specifically I’ve mulled over the idea of using an inflatable device to achieve said movement.
The device would be inflated to maximum capacity at the beginning of a print and would deflate gradually via an electronically controlled valve.
The printer would have to be encased, I surmise, and the temperature within regulated carefully to achieve uniform air pressure.
However, I believe it could be significantly cheaper and more durable/reliable; and could be improved upon more rapidly via software development than current motorized methods.
I would also like this to be an open door to discuss alternative methods of operation for 3D printers in general.
Your thoughts, please.
Funny you mention this, when I was wrestling with my z I considered using something hydraulic, but then we sorted it out
You wouldn’t want to use air as it is compressible, you would not have very good control of distance. I also don’t thint it will be cheaper, quality pneumatic/hydrolic controls are more expenisve that $10 steppers.
Indeed, but I believe that the heat generated by the hot bed might give the air better properties for the application, and I believe that the compression could be compensated for with calculation.
I imagine the control of distance could also be achieved with experimentation and calculation, which is one of the specific reasons I thought of it, because the math is free if you know how to do it. Whereas hardware constraints are more of a concern with current methods I believe.
When you figure in all the costs I believe the difference wouldn’t be so great, and especially in terms of long term reliability I think you’d save quite a bit.
But I’m not familiar enough with pneumatic/hydrolic systems.
Does any one know of a valve that could possibly be utilized for the operation?
Vibration is a big issue, and air pneumatic systems would shake around a lot. You’d have to add significant damping to your z axis, or as said use hydraulics. McMaster-Carr have hydraulic valves, but hoo boy are they expensive – because generally they’re intended to run at tens of atmospheres of pressure. I don’t know of any low-cost low-pressure hydraulic systems, although they may well exist.
I’d have to agree with @Misha_Tikh - air is not a suitable medium for precise movements, especially when there’s a load involved, since air gets quite springy when there’s a dynamic load involved. This circumstance improves as pressure improves, since air compresses absolutely nonlinearly.
Air is only usable for precise positioning when you have some kind of closed-loop control in place (with normal layer heights, we need Z accuracy to be better than around 10µm). Usually glass scales provide that feedback for high-precision applications, but the cylinders and feedback system easily cost more than the whole rest of the printer.
Thanks for the feedback, I appreciate this insight.