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cozmicray
did you get some of these ball screws?
Hi, sorry no I didn't order them. Although I am tempted, I'm not sure if I want to build a LISA. I like the concept and would like a delta printer that is strong and sturdy enough for a multi direct extruder and light milling, I'm not sure if this is the way to go. I guess the main problem is that any forces acting on the effector (acceleration / deceleration but for milling also buffets) directly act on the precious ball screws. Like Nicholas said, as soon as they bend it's all over. So it's not really something that helps me with what I ultimately want (print large scale simultaneously with 3-4 different materials).
I thought about stabilizing the leadscrew but it's difficult because of the rotating carriage. I guess the best way would be to go back to the delta design and have a wheeled carriage on an extrusion and use the ball screw instead of a belt. But that is just much more expensive.
I'm still trying to get my first printer (Kossel Mini) working but I try to build a "wheel screw", a rubber wheel on a precision steel rod.
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VDX
... for a better DIY-able 'recirculating bearing' concept cylinders instead of balls are even better for linear bearings ... simple cut a smooth rod in short pieces and fill them into the tray ;)
I thought about this too in the thread. I wonder if you could actually use "rubbery" recirculating rods for a threadless lead screw? The rubbery mini rods would circulate in a spiral around the rod, having friction in one direction but rotating freely. Probably not feasible because when the mini barrels touch each other they would create high friction and also have friction recirculating back. Just another crazy idea :) In any case, the delrin balls are really cheap and precise. I dream about being able to print something like this completely assembled with 3 materials, low friction hard material, rubbery flexible material and easily dissolvable support material.
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cozmicray
What are "these"
link is not right?
Please explain these recirculating ball screws?
Not sure why the link doesn't work, but FYI below are some more links. The link is simply to make a "DIY" printed linear bearing that runs directly on extrusions (like lm8uu bearings but for extrusions instead of rods). This saves you wheels and mounting them etc. Theoretically this could save time and money and space, practically it's probably a bit more hassle. I want to try to build this though because it's cool.
My idea was probably better explained as "lazy-suzan rings" (didn't know the name) to create "typical" delta effector platform that can carry multiple extruders. Basically a big bearing with effector in the middle the arms attached to the outside. This concept will likely not be bearing fruits (sorry for my unbearable puns!) since Nicholas multi extruder concept looks far easier to build. Also the problem that shoulder joint offsets and effector joint offsets need to be the same if I understand correctly, so the bigger the effector, the bigger your shoulder and you loose even more print space.
[github.com]
[github.com] (updated, easier to print version)
[www.flickr.com]
[youtu.be]
Sorry for the long post and noise!