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Linear Motion Tradeoffs
06/30/2022 at 02:28 • 0 commentsIn thinking about and designing 3d printers, cnc machines, and random robotics things, I always seem to come back to motion systems. Usually linear motion systems. I can find a lot of subjective things like "ball screws are better than lead screws, and linear rails are better than v-wheels," but by how much? In what specific ways? And is that even true, or just false knowledge passed down by people repeating what they have heard?
As far as I can see it, there are two separate parts of a linear motion system: the drive, and the support. And there are a large number of measurements where some combination of systems may excel or fail.
Drive Systems (in no particular order)
- Rack and Pinion
- Chain and Sprocket
- Timing Belt
- Lead Screw
- Ball Screw
- Solenoid
- Maybe others?
Support (in no particular order)
- Linear Rail
- Lead Screw
- Ball Screw
- Linear Rod
- V-Wheels
- Conveyor Belt-style-thing
- Probably many others I am not thinking of
Objective Measurements
- Maintenance Required (oiling, etc.)
- Maximum Load
- Maximum Distance
- Speed
- Backdriveability
- Noise
- Inertia
- Friction
- Vibration
- Backlash
- Initial Setup (belt tensioning, for example, other methods of setting preload)
- Differences per axis (for instance, my gut says lead screws can use gravity as a form of pre-tension, meaning they probably inherently work better as a z-axis)
- Probably others
I would love it if there was a list somewhere where someone has done the research and laid out in fairly objective ways the pros and cons of the different combinations. I haven't been able to find anything though.