An unexplained feed failure. No mechanical failure this time.

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cj7hawk
Posts: 95
Joined: Tue Dec 25, 2012 7:52 am

An unexplained feed failure. No mechanical failure this time.

Post by cj7hawk » Fri Mar 15, 2019 11:52 am

So I was printing a model, and after about 10 minutes, noticed it was printing to air. I waited a little, since it's a complex model and wasn't easy to see that it had stopped printing, but then I opened the filament door and lightly felt the filament and sure enough it was stationary.

My first thought was "Damn, heads jammed up again," and so I did a withdraw and looked at the filament.

It was perfect. The marks showed no sign of jamming at all. The filament was clean, to spec ( UP filament ) and showed clear marks where it was feeding, without any stretching, gouging or other signs I'd expect with a filament feed problem.

So I loaded it back, and then it took me 4 attempts to get it to print again - it went through the motions and simply didn't start printing. I was about to turn it off and reinitialize it when it started and so it's trying again.

I recall UP was looking into this, and this is the first time I can say it was definitely a software failure - it simply stopped feeding during print. Many of my previous feed issues were caused by a dirty hot end, but now I know what I'm looking for I can say that this one was not.

I've worked out I can check it more easily now by pulling the feed "straw" out while printing, and if feeding, it gets drawn back into the head slowly, showing me the filament is feeding.

But is there any news on a new firmware fix for this?

Thanks
David.

BigE79
Posts: 40
Joined: Fri Oct 26, 2018 9:18 pm

Re: An unexplained feed failure. No mechanical failure this time.

Post by BigE79 » Fri Mar 15, 2019 10:29 pm

Hi David,

I had a similar issue a while ago where it would stop extruding mid print and this was happening consistently.
My issue ended up being the extruder motor itself. At first I thought it was the IDC cable going to the head but this was not the case. The motor was simply intermittent and would sometimes just stop.

It's actually quite easy to check if you have the same issue. The ABS and PLA heads are almost the same, only the fan box (air guide) is different. You should be easily able to swap over the fan box from one to another, change heads and start printing again. My Supplier replaced the head for me after this proved to work but to be honest I'm still printing with the PLA head converted to ABS as there's no difference. If you try this you can at least see if the issue is hardware or software as you'll essentially replace the motor, head, heater and temperature sensor in one hit.

The only other thing I've observed to stop the extrusion is the filament getting wrapped up under itself on the roll. This is an obvious jam and only seems to occur if a roll is close to empty. I've never had the nozzle clog up and I've done about 3.5Kg of printing in ABS.

Cheers,
Erik

Owen Sparks aka Marksman
Posts: 564
Joined: Tue Mar 15, 2016 9:56 am

Re: An unexplained feed failure. No mechanical failure this time.

Post by Owen Sparks aka Marksman » Mon Mar 18, 2019 7:29 am

BigE79 wrote:
Fri Mar 15, 2019 10:29 pm
...The ABS and PLA heads are almost the same, only the fan box (air guide) is different...
Erik
Sorry Erik, but that isn't quite the case.
Extruders.JPG
Extruders.JPG (36.75 KiB) Viewed 86 times
Owen S.

bjorn
Posts: 102
Joined: Fri Aug 10, 2018 6:00 pm

Re: An unexplained feed failure. No mechanical failure this time.

Post by bjorn » Mon Mar 18, 2019 7:36 am

(In case Owens point wasn't obvious; the teflon lined PLA hotend should not exceed 240C as the PTFE will start to degrade)

BigE79
Posts: 40
Joined: Fri Oct 26, 2018 9:18 pm

Re: An unexplained feed failure. No mechanical failure this time.

Post by BigE79 » Mon Mar 18, 2019 9:20 pm

Okay, I didn't realize. I was following the instructions from the seller.
Regardless the PLA head has been working with ABS for a long time now. I guess I can't use this head for PLA anymore if the PTFE is damaged but I've never tried printing PLA with this machine anyway.

fastm3
Posts: 7
Joined: Wed Mar 13, 2019 9:33 am

Re: An unexplained feed failure. No mechanical failure this time.

Post by fastm3 » Tue Mar 19, 2019 9:47 pm

I've got the same issue a few times and especially with petg but also with abs. The curved feed may be the reason. Probably too long on my model it is always sliding/pushing on the windows. I've put the filament roll on the top without the guide and the issue has disappeared...
A too low temp may be also the reason. But I still have to think about a convenient way as the lid is partially open with that test setup ( so it means other issues with abs ) and the filament sensor is not used.
I've had similar issue with others printers and it was the extruder motor which was working but "tired". Each 2500 hours, I had to change it. But here my up300 has less than 200 hours.

bjorn
Posts: 102
Joined: Fri Aug 10, 2018 6:00 pm

Re: An unexplained feed failure. No mechanical failure this time.

Post by bjorn » Wed Mar 20, 2019 9:40 am

BigE79 wrote:
Mon Mar 18, 2019 9:20 pm
Okay, I didn't realize. I was following the instructions from the seller.
Regardless the PLA head has been working with ABS for a long time now. I guess I can't use this head for PLA anymore if the PTFE is damaged but I've never tried printing PLA with this machine anyway.
ABS doesn't damage the teflon, high temperature degrades it. Its just a piece of teflon tubing, so it can be replaced, although it can be a bit tricky to cut perfectly perpendicular and the exact right length. However its no so expensive that some trial and error won't make it worth it compared to the cost of the print head. Only reason they use it is because its cheaper and less likely to clog than an all metall hotend, with the trade off being the lower operational temperature.
fastm3 wrote:
Tue Mar 19, 2019 9:47 pm
...it was the extruder motor which was working but "tired". Each 2500 hours, I had to change it. But here my up300 has less than 200 hours...
I'm sorry, but I laughted a little, stepper motors don't get tired. The bearings wear out, the magnets overheat and demagnetize or the insulation in the coils wears down. But they're usually rated for around 100C operational temperature, so bearings is the most likely culprit.

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