Filament Clogs Extruder

[PondHawk]

We are printing a small 4”x4” enclosure for a PCB we manufacture using a FlashForge Guider II with Inland 1.75 ABS filament. Our printer makes about eight complete boxes per week. Admittedly not a high volume play… but it’s all we need for now. The attached image shows what I’ve been pulling out of the extruder after the ABS flow stops in the middle of a build. Something happens to jam the filament in or above the tube that guides the filament into the hot zone of the extruder. The print runs continue even though nothing is being built. It doesn’t happen too often but when it does there’s an ordeal that I have to go through to get at the guts of the print head and then time soaking the head and tube in acetone to get the ABS dissolved... it’s a little time consuming.
What I’m wondering is if this is a filament quality control issue?
Is there an adjustment that needs to be made in the hot zone?
Does the plastic tube that feeds the filament wear out?
20200828_154253.jpg

[fred_dot_u]

Have you considered to increase the nozzle temperature by 5°C to see if that helps?

[PondHawk]

Well, the extruder temperature is set at 239C and the max on the machine is 240C. When I set it at 240C the print will not start. So I'm working at the max temp allowed by the software.

[fred_dot_u]

I usually print ABS at 250°C, but I've determined that the reported/set temperature is likely lower than reality. Even my PLA runs about ten degrees hotter than "internet average." Because you have a high temp limit, consider to slow the print speed by about 10-15 mm sec. It's a drastic change, but this is only a test. If you find that the clogging goes away, there's insufficient thermal mass to keep up with the material flow/speed.

[Gambo]

I regularly use abs for small scale production as you What has become clear to me is that all abs filaments are not Equal. The filament we have found best is ABS-X made by Mitsubishi Chemicals in Holland (MCPP)but is only sold as own brand filament the one we purchase is 3dFilaprint ABS-x but in UK Ooznest also sell the same material as ABS-plus. The manufacturer recommends 240 to 260C for printing I have used it down to 235C. I print at 70mm/s. bed at 80C.

About your blockage it can occur because the tube which feeds the filament to the heater zone is not firmly against the nozzzle and leaking melted filament which hardens and causes a blockage.

[curious aardvark]

yeah - any of the above.
but first and easiest thing to try is a different brand or roll of filament.

If you still get the same issue - then start taking things apart :-)

[Gambo]

So True !!
I think some brands of filament are almost unusable. I spoke to the manufacturer of one acetal filament and got the feeling they hadn't a clue either heat your enclosure to 70C.

I would still like to know what material and brand you are using

[PondHawk]

The brand I am using is Inland. I've used 20+kg of this brand and I would say that it is mostly good. That was why I wondered if it might be in the machine.
I contacted the manufacturer and they don't think there's a problem so maybe its just a maintenance thing. Another 3D printer with a lot of experience told me that he changes the Teflon guide every 5kg. I think I'll try that, and buy a different brand.

[Gambo]

If you have used this much of the filament unless there has been a change they don't want to tell you about I think you can rule that out as aardvark said time to start stripping things down!!!! even so for the cost of a roll of another quality filament I would still give that a try.

[curious aardvark]

the teflon tubes - if you've mainly been running pla - don't really wear out.
The one in my delta was there for about 2 years and 6 km of filament. Only reason i changed it was that I'd snapped anozzle off in the heatblock and had to replace the whole lot :-)

Unless you are regularly running filament that prints at 240c and higher - the ptfe tube should not wear out.

You can get dodgy rolls of filament.

earlier thjis year I was using a silver/grey from ebay that cost £10 a roll - delivered !
Just about the best filament I've ever used.
The third roll just blocks the nozzle, no idea how but the only way round it is to replace the nozzle.

I even tried unravelling about a 1/4 of the roll - in case it was just a bad patch at the start - nope - 2 more nozzles later I just gave up and threw it away.
And let me tell you getting 0.5mm nozzles, by themselves is not easy.
In the end I bought a packet of 20 assorted that came with 2 0,5's - as that was cheaper than buying a single 0.5 by itself.
What i actuially wanted was a pack of just 0.5's - but nobody seems to do that.

And the sad thing is - I'm just not going to bother with that filament again. But man it was good.
My current favourite budget pla is BQ brand.
Excellent stuff.

So it could just be that one roll.
Try something else. Or another roll of the same stuff