Thursday, April 4, 2019

Time for a ball screw printer

While thinking about how to upgrade my Delta printer, I was considering the viability of using ball screws instead of pulleys and belts. However since the movement of the carriages is sometimes 4 times greater that the actual speed of the print head, this seems like a bad idea.

That lead me down onto a path of comparing the existing printer designs.
  • Cartesian: The classic, but moving the bed just creates unnecessary acceleration artifacts.
  • Delta: Looks good, but the aforementioned speed issue, salmon skin/moire and the extra z height cause some issues
  • CoreXY: The underdog, seemingly combines the best from the previous designs, however the long belt path wont be good in combating acceleration artifacts.
  • Cross-Axis/Ultimaker: That could be the one. No moving bed, short belt path and a contained frame, make this a promising option.

With a cross axis design, we would only need one ball screw per axis. With the rigidity we gain from the ball screws we could probably get away with not using a bowden extruder.

That leaves just calculating if we can get cheap enough ball screws and if a normal NEMA17 can drive them fast enough...



This looks pretty much like the design I would go for.

Sunday, March 31, 2019

Reload, reset, relaunch. New content coming

I admittedly slacked of a bit, but now I feel motivated again.

I want to launch two new series of content.

Useful Products:
There are not many useful 3D printed products out there, but they do exist. Until we find a killer app for 3D printing, we have to start somewhere. Everyone is invited to find products or applications for 3D printing, so we can collect them and really show what 3D printing is capable of.

Advanced technical testing:
Beyond the China kit printers, there are still lots of interesting developments and ideas to test to make reprap machine better. I want to answer questions like what is the relationship of actual extruded print volume to commanded volume?, are 0.9 degree stepper motors worth it?, should I counter balance my effector? or are TL smoothers a scam?
Of course some questions I cant completely test out but at least I can try to find arguments from all sides on forums etc. to give some interesting insights.

In addition I want to document my printer upgrade progress and aforementioned testing on Youtube, which also allows me to give back to the community. I thought I could start a regular lifestream, where we/I can fix some printer issues life. I know Thomas Sanladrer sometimes does stream under the #3D-Doc, that seems like a cool idea to me.

PS. Is anyone interested in developing a ball screw driven cartesian printer? :D