Large Kossel

[Glacian22]

Hey all! After being very happy with my rostock max v1, I decided to try building a scaled up mini kossel for a friend of mine, and I've run into an issue. I used Johann's frame size calculator to choose my aluminum extrusions length, ending up with 500mm horizontals (and 400mm arms) to give me about a 14 inch diameter build area. Once I put it all together though, I found that the range of motion only allowed for an 11 in build area...so right now it's a huge printer with only a largish build size.

While trying to figure out how this could've happened, since the calculator should've been correct, I started to wonder if it's because the size of the effector doesn't scale up with the overall machine. As in, if I redesigned the effector to be significantly larger, would that have the effect I'm looking for of increasing the build area? Or should I just go buy some longer carbon fiber rods for the arms?

Thanks!

[stonewater]

you need longer arms. the build area is a function of the geometry of the arms. and it will need to be tall enough to allow the longer arms to get to the areas directly under the carriages in all 3 axis.


Tom C

[teoman]

For the 3 inch difference from 11 to 14 you would need to make the effector platform larger about 3 inches in diameter which will make it massive. And as the effector iplatform is huge you would lose half the radius of it ( the platform will hit the towers before the nozzle can reach the end of the build surface).


So yeah, you need longer arms --> and therefore taller towers to meet your original design.