Last summer I lost a rod cap. While I could have replaced it with one of those universal rod caps, I preferred the slim profile of the original. Figuring that the easiest way to replace it would be to 3D print one, I set out to design a replacement. I drafted up and tested a few designs. Getting to the final version took a lot more work than expected, but I think the result was worth it.
Unfortunately, I lost that rod cap too. It fell out due to an interesting failure mode called cold flow, which was an inherent weakness in the plastic I used.
To fix this I picked up some new (better) plastic and 3D printed a new one.
Nissin Zerosum Oni 450 with original end cap (left), and Nissin Zerosum Oni 395 with 3D printed end cap (right)
Works great!
The original rod cap got lost while walking through thick brush. It seems like an inevitability with the way the end flares out; a design I didn’t replicate in my replacement.
Looks great, I’ve done similar with my lost rod caps. I also printed some better rod caps for my Tenryu TF32TA which had a very loose fitting cap that wouldn’t stay in. It is a lot of work to get it right and get the fit neither too loose or too tight. I used PET-G on mine and I have a Prusa MKS3+.
I hear you on loose OEM rod caps. Seems like sometimes even the manufacturers struggle to get it right.
I started with PETG too, but had to switch to PC. My design uses a lot of flex, which makes it easier to size, but leaves it vulnerable to cold flow (failure due to slow plastic deformation). Ideally, I would have used a really stiff design, like a cylinder with a groove cut in it, but I found the amount of friction from that to be really variable.
Currently rocking a Prusa MK4S myself, but my eyes are on that Core One upgrade kit
Care to share a pic of how your rod caps came out?
