MK3S nozzle not aligned with thumbtack in purge mechanism
@bigbrain3d, I will see if I can capture a failure on video, and to answer your question, I bought/built my MK3s in late April of this year.
Did you buy a kit? It looks like the kapton tape is very wide. Did you use your own kapton?
@bigbrain3d Yes I bought a kit, but after trying most of the things I saw in the forum, I tried to use a wider strip of kapton tape to see if that would help, obviously it didnt.
I think that is the issue. Everything else seems perfect. The failure happens because after 20-30 blobs because the kapton & tack heat up and stick much more to the molten plastic.
One of the secrets we found to get the Retractable Purge Mechanism working was very narrow kapton. Then it stuck just enough to make the blob but the stick was low enough that it released after the fan cooling cycle.
The good news is that it's an easy fix. 2mm kapton width is the solution.
@bigbrain3d I still have some of the kapton tape that came with my kit, but the issue was happening prior to me "upgrading" to the wider tape. Another question I had was, if I changed my blob size to say 35, instead of 40, would that keep it from hitting the washer? Is that logic correct, or from the videos you are sure its not the washer height?
Thanks for all your help with this, I cant wait to get this to a point where I trust it on longer prints.
You could reduce the extrusion to 35mm. That would move the blob lower.
@bigbraind3d, finally got around to reassembling the mechanism. Here's a video of the purge. With 4 springs, it will eject the blob, but it pulls the washer away from the back edge as shown in the photo taken after the ejection. I measured several blobs. From base to tip, they measured 3.87, 3.67, 3.65, and 4.71mm. That last one (the first blob actually printed) was kind of misshapen. I had to push the washer back after each one. Do you think some superglue would help hold it to the back edge?
You can find the video and photo here:
From the pictures it looks like the washer is not pushed in all the way.
From the video I cannot see the relationship between the blob and the washer. Otherwise it looks like a perfect blob.
Superglue may hold it in but the blob should never actually touch the washer at all.
I feel like something is wrong if you need 4 springs. 2 or 3 should work, 3 at the max. Does the mechanism actuate smoothly?