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Problem with extrusion consistency  

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MrFlippant
(@mrflippant)
Trusted Member
Topic starter answered:
Re: Problem with extrusion consistency

Regarding the tensioner screws, where do people seem to find the best setting?

In the assembly manual, it indicates the screw heads should be just about flush, so I set them just proud of the 3D part. When the filament is loaded, the screw heads are just a little lower than the surface of the 3D printed part.

Is this how other people have it? If not, where should the screw heads be for PLA when loaded and/or unloaded?

Respondido : 24/05/2018 7:54 pm
motocoder
(@motocoder)
Trusted Member
Re: Problem with extrusion consistency


Regarding the tensioner screws, where do people seem to find the best setting?

In the assembly manual, it indicates the screw heads should be just about flush, so I set them just proud of the 3D part. When the filament is loaded, the screw heads are just a little lower than the surface of the 3D printed part.

Is this how other people have it? If not, where should the screw heads be for PLA when loaded and/or unloaded?

I did some experimentation, and I find that 5 turns on each screw is sufficient.

Respondido : 24/05/2018 9:24 pm
richard.l
(@richard-l)
Miembro Moderator
Re: Problem with extrusion consistency

MrFlippant,

Sorry for the delay in replying. From the pictures you posted it looks like the tension screws are too tight. I have mine set so that the bottom part of the head is flush with the outside oc the extruder body. In other words I can see the whole haed of the screw on the ouside of the extruder body.

Respondido : 25/05/2018 2:58 am
MrFlippant
(@mrflippant)
Trusted Member
Topic starter answered:
Re: Problem with extrusion consistency

Yes, that's much looser than I usually have them. Is that when filament is loaded, or unloaded?

Also, can anyone explain why that tension seemed to work well for a while, before my current woes? Would too much pressure CAUSE clogs?

Respondido : 25/05/2018 6:35 am
richard.l
(@richard-l)
Miembro Moderator
Re: Problem with extrusion consistency


Yes, that's much looser than I usually have them. Is that when filament is loaded, or unloaded?

Also, can anyone explain why that tension seemed to work well for a while, before my current woes? Would too much pressure CAUSE clogs?

Again, sorry for the delay. I was on vacation and just now getting caught up.

Loaded or unloaded doesn't really matter since the other side (the one that lifts up) is where any visible changes will occur when filament is present.

Don't honestly know why it would work well for awhile and then suddenly not. I do know that the more pressure you exert on the filament with the gears will deform it and cause it to be harder to feed through the cold end before it reaches the nozzle.

Respondido : 29/05/2018 5:40 pm
MrFlippant
(@mrflippant)
Trusted Member
Topic starter answered:
Re: Problem with extrusion consistency

Back to square one. I replaced the nozzle while making sure the positioning is per the guide previously linked. Everything was fine for a few prints. Then I got word that a print I got going before work has failed. From the photo it looks like a hard clog at some point and the printer just stopped extruding altogether.

I had set my tension up with the 5 full turns and it was fine but I started noticing skipping again. Better when things are slow and with a slightly raised temperature. But now I'm back to where I was before.

It also looks like this is getting to be epidemic. Hopefully someone finds the cure soon.

Respondido : 29/05/2018 11:14 pm
MrFlippant
(@mrflippant)
Trusted Member
Topic starter answered:
Re: Problem with extrusion consistency

So, as I expected, there was a hard plug. On my way home, I decided to pick up an infrared thermometer to see if things actually get as hot as they are supposed to.

Are the temps shows on the screen supposed to be in C for both, or just for the bed? Either way, what I found was that the bed was registering approximately the expected temperature, but the nozzle was not. No matter what part of the hot end I aimed that thing at, I couldn't get a reading anywhere near the temps that my thermistor is reporting. Like, it might show 100c or something. Now, I get that trying to shine an IR thermo at such a small area is going to be hit or miss, but I couldn't get a comparable reading no matter where I aimed it.

I couldn't pull the filament out all the way because it broke where the gears had ground away at it, and I wasn't able to pull much up after that. I decided to snip it flush to the PTFE tube and try to load filament by pushing the blunt end of new filament against the blunt end of what was still in there. I also CRANKED up the temperature as high as it could go. I was then able to "load filament" and get it to extrude again. When the PLA first came out of the nozzle, I even saw a small puff of smoke, so it sure SEEMS like it was hotter than it needed to be. I turned the temp back down right away, so hopefully I didn't burn it in there and ruin my new nozzle, but still... WTF?

I have a bunch of helpful friends, some of whom actually do 3d printing, though with other printers, suggesting things like improper retraction settings that cause the clogging. I thought it might still be temperature related (hence the IR thermo) but I can't even verify the temp of the hot end outside of the thermistor. If that's reading wrong, how can I determine the accuracy of it? Is it even possible for a thermistor to be THAT far off? And if so, is smoking PLA normal? For some reason, I don't think so.

I really can't be expected to baby sit every print I do, especially anything over an hour (which is almost everything worth printing).

BLEH!

Respondido : 30/05/2018 6:49 am
Cory
 Cory
(@cory-6)
New Member
Re: Problem with extrusion consistency


So, as I expected, there was a hard plug. On my way home, I decided to pick up an infrared thermometer to see if things actually get as hot as they are supposed to.

Are the temps shows on the screen supposed to be in C for both, or just for the bed? Either way, what I found was that the bed was registering approximately the expected temperature, but the nozzle was not. No matter what part of the hot end I aimed that thing at, I couldn't get a reading anywhere near the temps that my thermistor is reporting. Like, it might show 100c or something. Now, I get that trying to shine an IR thermo at such a small area is going to be hit or miss, but I couldn't get a comparable reading no matter where I aimed it.

I couldn't pull the filament out all the way because it broke where the gears had ground away at it, and I wasn't able to pull much up after that. I decided to snip it flush to the PTFE tube and try to load filament by pushing the blunt end of new filament against the blunt end of what was still in there. I also CRANKED up the temperature as high as it could go. I was then able to "load filament" and get it to extrude again. When the PLA first came out of the nozzle, I even saw a small puff of smoke, so it sure SEEMS like it was hotter than it needed to be. I turned the temp back down right away, so hopefully I didn't burn it in there and ruin my new nozzle, but still... WTF?

I have a bunch of helpful friends, some of whom actually do 3d printing, though with other printers, suggesting things like improper retraction settings that cause the clogging. I thought it might still be temperature related (hence the IR thermo) but I can't even verify the temp of the hot end outside of the thermistor. If that's reading wrong, how can I determine the accuracy of it? Is it even possible for a thermistor to be THAT far off? And if so, is smoking PLA normal? For some reason, I don't think so.

I really can't be expected to baby sit every print I do, especially anything over an hour (which is almost everything worth printing).

BLEH!

I've got a headscratcher over here, too. For what it's worth, i don't think an IR thermo is going to be able to hit the nozzle/heat block precise enough to give the temperature you are expecting. Mine was set at 215C and the best i could get was 170C on the thermo but that took a very steady grip and lots of patience to hone in on the hotspot. My heatbed also seems to be off by 5-10C depending on the temperature i set.

Respondido : 01/06/2018 2:25 pm
MrFlippant
(@mrflippant)
Trusted Member
Topic starter answered:
Re: Problem with extrusion consistency

Sounds about right for my reading of the heat bed. I was happy it was within that many degrees. I haven't been having problems with 1st level adhesion, so called it good.

Since I've been printing with the heat up, everything has been great. I'm batting 1000 at the moment with successful prints. Even at this higher heat, I've got little to no stringing. I'll have to print a stress test of some sort, but I'm trying to get as much useful stuff as I can before it fails for some other reason. I'm already staring down the barrel of a failing print fan. It makes bad noises and spins up unreliably, like the motor is failing or whatever gearing is inside it is slipping. You'd think a part like that would last a while, even if it was a cheap POC. Plus my filament sensor hasn't worked since I updated the firmware... I should get a ticket going for some replacement parts under warranty...

Respondido : 01/06/2018 4:06 pm
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