Hi,
thoughts and opinions on using the IGUS plastic rod ends vs the ball and cup joints?
The rod end is tried and tested solution but the axis it rotates on must be extremely precise in diameter and metal but you do get an angle of 35° with some clever engineering.
The ball and cup on the other hand just snaps in place and the ball stud can be had in either metal or polymer version with absolutely zero play in the join. Downside being you only get 30° at most.

I tried using Igus rod ends several years ago. I was unable to get sufficient movement range even after machining some custom spacers. I ended up using magnetic ball joints, which work very well.

Edited 1 time(s). Last edit at 07/17/2024 02:23AM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I've read your blog. How come you weren't able to get high angle with these? I have them on hand (the ball and cup version too) and I've printed some test pieces and with a simple spacer you can get 35° easily. 37°-38° would be possible too.

... my first delta-demonstrator from 2007 (then named "tripod") too was built with double magnetic ball joints.

Attached some images of the hinges and the completed setup ...



Edited 2 time(s). Last edit at 07/17/2024 04:36AM by VDX.

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

it's not feasible for me to use magnetic ball joints

... with the double-ball joints you''ll have a "nonsingular" joint, so the kinematics are more complex ... but with only one magnetic ball, an iron-counterpart and a PTFE-ring to give some microns distance, it's the same, as with the ball'n'cup joints

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

What "double ball joints"? The IGUS joins are either a simple rod end or a ball and cup with a simple " bearing" plastic part in the middle making it slip better.

... the "double ball joints" were my solution for a "stick'n'slip" problem when using it for etreme fine positionig -- if you look into my images, every joint consists of 2 ball magnets, rolling on each other, so no gliding and no stick'n'slip (was meant for micro-positioning with a working range of below 50mm square and step resolutions near to single microns).

But then too, the "joint" is not a single one, but two moving coordinates per joint, so more complex calculation for the IK-solutions (not needed, when a single ball per joint) ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
dc42
I tried using Igus rod ends several years ago. I was unable to get sufficient movement range even after machining some custom spacers. I ended up using magnetic ball joints, which work very well.

What was the reason you weren't able to achieve sufficient movement range?

Hi,
I've noticed you can get custom CNC parts from IGUS. Since stuff like Igumid G is extremely smooth (I have the rod ends in both the "normal" W300 material and in G and the G version is 10 times smoother to move) it might be interesting to instead have a ball and cap mechanism akin to industrial delta robots made.
What do you think? Cost aside what should I look out for?

Interesting spacer design for the KARM/KALM IGUS rod ends from SIPRO srl.

I have a growing suspicion these are common IGUS parts not featured in their catalogues.

... yes, there are several slightly different ball-joint-designs ... and, too, the design of the "actuators" -- look here for another basic concept without linear slides: [new.abb.com]

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]