How to run a 5 head with only 4 heads? (number one head disconnected)
My new 5 head XL has messed up head one.
I set a multi-day print going late evening, looked in on it in the morning and found it beeping away with number one head nozzle completely covered with a very large lump of solidified PET-G.
I couldn't do much with it on the machine, so I unlocked it, disconnected it and took it to the bench to examine it. After deciding I couldn't do much about it- a 50mm cube of solid PET-G is going to take some removing- I emailed support and am waiting for a response.
Later I went back to the machine and thought I would just move the filaments along one to the next heads and print with the remaining four heads, but the machine refuses to go past an orange error screen which tells me "Puppy dwarf_1 not responding" which I presume is prusa-speak for head one is not responding?
So my question is- while I am waiting for this problem to get sorted is there a way of telling the machine to forget about head one and just use the rest?
At the moment my brand new XL is just a very expensive paperweight!
Ken.
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
why not connect head one back again and heat up so you can carefully remove the mess? that should not be a big problem.
Look up 'Blob of Doom' to see how these are dealt with 'though most will be Mk3 or Mini based - this is the first XL BOD i've seen on the forums.
A combination of preheating a few degrees above printing temperature and maybe carving away chunks with a soldering iron or a heat gun should shift the worst of it so you can begin clean-up and assess the damage - if any.
Cheerio,
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
Many thanks to both of you for the help, I found & watched a video on it so now I will try to remove it all without damaging anything.
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
I got a big one early on that jammed into the side of the machine when the tool tried to park. I got it off by heating it up to a bit past printing temp and waiting about 15 minutes. When I came back, it had fallen off on its own. I scraped the remaining goo off by cooling it down to about 170C and using a brass brush. I didn't have to take anything apart to clean it up.
Many thanks to both of you for the help, I found & watched a video on it so now I will try to remove it all without damaging anything.
RE:
And if you want some entertainment, surf the 3d Print Blob Of Doom Gallery, on line here: https://www.flickr.com/groups/14741465@N23/pool/
(One just added tonight, one of mine, unfortunately.)
Look up 'Blob of Doom' to see how these are dealt with 'though most will be Mk3 or Mini based - this is the first XL BOD i've seen on the forums.
A combination of preheating a few degrees above printing temperature and maybe carving away chunks with a soldering iron or a heat gun should shift the worst of it so you can begin clean-up and assess the damage - if any.
Cheerio,
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
Thanks JSW- some of them make mine look quite insignificant!!
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
And many of those look worse than they actually are.
Many of them can be fixed with little or no damage to the machine by carefully heating and removing the plastic that is not supposed to be there'
'Heat got you into it, heat can get you out of it.'
Thanks JSW- some of them make mine look quite insignificant!!
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
Replacing the head & heat-soaking it did the trick, most of it fell off and the rest came off with careful use of needle-nosed pliers and various scrapers.
So I tried again with pet-g but with a different, slightly smaller model but still pet-g. That also failed in a similar manner to the bigger model.
So I changed to pla and repeated the smaller model- re-sliced for pla of course- that worked exactly as it should with excellent results.
So that leaves the common factor being the pet-g. It was a never-used, still in it's sealed bag from Prusa, 2kg roll of recycled pet-g. The worry for me is if it is bad, are the other two rolls also bad?
I tend to think (hope?) not as it will be a considerable waste to throw then away.
One question that does occur to me- I had the three rolls of pet-g in heads 1-3, and 2 rolls of pla in heads 4 & 5. The print that failed was set up to spool-join 1-3 and ignore 4 & 5= but would the mix of filament types have confused the printer in some way? Can it handle a mix like that?
Another data point, each time it failed, the first couple of layers were perfect, adhesion to the bed was excellent, it only started to go wrong from the last (3rd) base layer, with obvious signs of the filament not fusing together, and short bits of filament scattered all over the enclosure.
Any thoughts or ideas on the root cause or causes, or ways to make sure it doesn't happen again?
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
Any thoughts or ideas on the root cause or causes, or ways to make sure it doesn't happen again?
Does the issue affect just one tool or is all tools using that filament?
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
If you mean root causes of a Blob Of Doom, it's almost always because the print in progress breaks off of the build plate.
Root causes of a print breaking off can be a dirty plate (remember, kiddies, clean your plate and clean it MY WAY!), and/or a bad Z calibration or maybe even wonky filament.
I guess you might also say that one root cause of a BOD is letting the print run without periodic inspection. If you catch it quickly, you can stop it before a significant blob develops.
RE: How to run a 5 head with only 4 heads? (number one head disconnected)
JSW, none of the failed prints became detached from the bed- as I said in my last message, the first two layers each time were excellent, good adhesion to the bed and a properly smooth undersurface.
In each case I had to move the bed down and then peel the failed print off the bed.
EastMemphis, I didn't think to try it with one of the other heads- good thought though, I will try that. I will also try one of the other two new rolls to see it that changes things.