Is there a way to prevent damage when a print is knocked over?
I got back to the office today to find that the base of the print didn't stick properly and was knocked over by the nozzle. The print kept on going until completion, so around 40g of PLA were extruded mid-air, creating this blob that imprisoned the hotend and its cables, breaking the fan exhaust in the process.
In your experience is there a way to prevent this kind of failures? I can deal with some wasted material, but having to replace the hotend is a massive pain.
Thanks
RE: Is there a way to prevent damage when a print is knocked over?
If it were me (results not guaranteed), I would judiciously use a good heat gun to soften that mess to remove the main chunk.
Don't melt your extruder...
Then heat up the hot end to your extrusion temp (assuming wires not broken) and use a brass brush on the rest.
Good luck - that is one ugly blob...
Going forward - change your technique to maximize adhesion. You don't tell us what print plate, so can't be more specific.
A brim pretty much always helps if in doubt.
RE: Is there a way to prevent damage when a print is knocked over?
Search here and learn about hotend socks. They can help reduce/mitigate damage when it does happen in the future.
RE: Is there a way to prevent damage when a print is knocked over?
@robert-rmm200
I have the powder coated sheet. It was probably just dirty and I didn't realize it. This printer printed a lot in the past year, so the Z-calibration was ok.
I disassembled the hotend but it's really a mess, even with a hot gun I can't really clean this up, I'll take the chance to change the hotend and upgrade to a MK3S.
Oh, and I learned today about hotend socks, that's going to be a must have 🙂
RE: Is there a way to prevent damage when a print is knocked over?
I set alarms every few hours, so I periodically look at the print job via Octoprint's webcam server. That doesn't prevent the blobs of death, but limits how severe they can become.
+1 on the silicone socks reducing the amount of damage.
RE: Is there a way to prevent damage when a print is knocked over?
Silicon sock is the best insurance. I don't recommend the PRO version though, it has a good chance to knock the print loose all by itself: the thin cover over the nozzle tip sags and has caught prints when I was using one. So now I only use the non-pro version that exposes the entire nozzle. It still helps prevent the encrustation mess. Albeit, the sock does not protect the heater and thermistor wires; they are still exposed. Maybe a layer of high temp silicon tape... but I've not done that.
RE: Is there a way to prevent damage when a print is knocked over?
Do your powder coated sheet a favor and scrub it with water and Dawn. (not Prusa recommended - but we do what works)
Run a print to dry it thoroughly.
Do this every month or so. It really helps adhesion.
RE: Is there a way to prevent damage when a print is knocked over?
A silicon sock has prevented the blob of doom on all of my printers on numerous occasions. I would not use any of my machines without one. My printers operate for days on end on some prints without supervision. I use geniune standard e3d silicon socks, I would stay clear of the pro version with the small hole because they are unreliable at best.
RE: Is there a way to prevent damage when a print is knocked over?
I intentionally use a pro version sock for its more complete coverage, BUT I slice away the part that covers the nozzle. That gets rid of the stupid tendency to catch on prints. The advantage is keeping more coverage for the rest of the heat block assembly.
For high temp printing, mold yourself some silicone socks out of Permatex high temp "copper" gasket silicone. The E3D socks rapidly deteriorate if you are in the 280 - 290C range.
With a silicone sock in place, blobs of doom tend to be smaller or be easier to manage spaghetti monsters.