Custom Kissel design question arm length/angle I designed what I call a micro Kossel delta. Initially I used a traditional "hanging" hot end whose distance from the nozzle to the arm attachment was about 20mm. It had a volume diameter of about 70mm and z height of about 45mm. It worked great right off the start. Almost no tuning or leveling needed, just some speed and temperature tuning. I wanted more z height so I put on a Flsun style end effector that pulled the hotend up about 35mm. I have had nothing but nightmares since. Problems with movement, repeatability, over extrusion, under extrusion, lurching, top facing being sparse, you name it. Is there some Kossel design rule about how long the arms can be for certain center arm angles or something? I am ready to give up and go back to "shorty"! Is there? Thanks, DLC https://reprap.org/forum/read.php?4,812815,812815#msg-812815 Thu, 12 Mar 2026 15:43:17 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?4,812815,813857#msg-813857 Re: Custom Kissel design question arm length/angle https://reprap.org/forum/read.php?4,812815,813857#msg-813857
Lessons learned:
Not EVERYTHING works. The larger radius FLSun end effector worked fine on a delta with 220mm rods, not so much on a delta with 105mm rods.
Small changes have BIG effects. The mini-Kossel end effector has a 20mm radius, the FLSun is 30mm. The former works, that latter, not so much.

I think I'll put the details of my 300mm tall Micro-Kossel on Thingiverse as soon as I get all the details collected.

Thanks,
DLC]]> dlc60 Reprappers Sun, 11 Mar 2018 00:23:18 -0500 https://reprap.org/forum/read.php?4,812815,812916#msg-812916 Re: Custom Kossel design question arm length/angle https://reprap.org/forum/read.php?4,812815,812916#msg-812916
Quote
o_lampe
The printed effectors are only as good as the printer which made it. There can be several issues with it.
Rod-pairs not parallel: The distance between rods at the carrier must be the same as at the effector
The effector triangle has to be equal length: The angle between rods axis' is 60° all around?
Stiffness of the printed part, including the heatsink clamp.

The effector is a commercial one (FLSun), which may or may not mean anything... I checked to make sure the carrier arm spacing was the same as the effector. The printer was running before with home built mini Kossel end effector and worked great. The electrics are fine as is the wiring. The hot end is the same as well. The _only_ change was the end effector.

The big deal I see is that the end effector speeds up and slows down which causes thinning and bunching of filament laid down. If I send a single long G0 command I will see the speed up and slow down during the traverse.

Confused...
DLC]]> dlc60 Reprappers Sun, 04 Mar 2018 12:47:47 -0500 https://reprap.org/forum/read.php?4,812815,812833#msg-812833 Re: Custom Kissel design question arm length/angle https://reprap.org/forum/read.php?4,812815,812833#msg-812833 Rod-pairs not parallel: The distance between rods at the carrier must be the same as at the effector
The effector triangle has to be equal length: The angle between rods axis' is 60° all around?
Stiffness of the printed part, including the heatsink clamp.]]> o_lampe Reprappers Sun, 04 Mar 2018 02:42:51 -0500 https://reprap.org/forum/read.php?4,812815,812815#msg-812815 Custom Kissel design question arm length/angle https://reprap.org/forum/read.php?4,812815,812815#msg-812815 I wanted more z height so I put on a Flsun style end effector that pulled the hotend up about 35mm. I have had nothing but nightmares since. Problems with movement, repeatability, over extrusion, under extrusion, lurching, top facing being sparse, you name it.

Is there some Kossel design rule about how long the arms can be for certain center arm angles or something? I am ready to give up and go back to "shorty"!

Is there?

Thanks,
DLC]]> dlc60 Reprappers Sat, 03 Mar 2018 19:30:43 -0500