- How do I calculate the optimal arm length?
I know there is a nice math paper floating around on this topic but someone else will have to track it down. Optimal can mean lots of things. Shorter arms get you more height. Longer arms get you a better build area to printer area ratio. Basically, there is no optimal length. You need your target specs to zero in on a target arm length.
- What bearing options do people use for the arms and what are their tradeoffs? (I've seen ball bearings and magnets, but I haven't seen any discussion on WHY some of these designs offer desirable properties and what they are)
Lot's of ways to skin a cat here. Traxxas rod ends are cheap and pretty good. They do have some play so bearings or magnets can help you step up your game. Depending on the implementation bearings or magnets could be better than the other.
- How important is the mass of the print head?
It depends on how important high accelerations are to you.
- How accurate should positioning of the three axes be?
It depends on your delta radius, arm length, and your target effector positioning accuracy.
I wish this was more clean cut. However, if there was a BEST way to do this then we would only have one machine design. We all have different ideas about what is important in a machine. Lots of factors to balance. Cost, speed, accuracy, acceleration, size, looks, etc
I know there is a nice math paper floating around on this topic but someone else will have to track it down. Optimal can mean lots of things. Shorter arms get you more height. Longer arms get you a better build area to printer area ratio. Basically, there is no optimal length. You need your target specs to zero in on a target arm length.
- What bearing options do people use for the arms and what are their tradeoffs? (I've seen ball bearings and magnets, but I haven't seen any discussion on WHY some of these designs offer desirable properties and what they are)
Lot's of ways to skin a cat here. Traxxas rod ends are cheap and pretty good. They do have some play so bearings or magnets can help you step up your game. Depending on the implementation bearings or magnets could be better than the other.
- How important is the mass of the print head?
It depends on how important high accelerations are to you.
- How accurate should positioning of the three axes be?
It depends on your delta radius, arm length, and your target effector positioning accuracy.
I wish this was more clean cut. However, if there was a BEST way to do this then we would only have one machine design. We all have different ideas about what is important in a machine. Lots of factors to balance. Cost, speed, accuracy, acceleration, size, looks, etc