We have a FT-5 R2 in our school, and we have been having extruder problems

DarthRevan 2018-06-13 21:06:04 UTC #1

In our school physics lab, we have an FT-5 R2 printer. We have had extruder problems twice now. Whenever we just put filament out it does fine, but when we try to print it will work fine for a few seconds. Then it will start spitting out small globs with small lines of a filament in between them. What kind of things could be causing this type of result?

heartless 2018-06-13 23:40:59 UTC #2

too close to the bed, perhaps?
that is what it is sounding like to me.

when setting the bed level, you should be able to "just" slide a piece of plain paper between the nozzle and the bed surface - it should move with just a slight drag on it.. not too tight as to make it difficult to move the paper, but not so loose that there is no drag at all

and this would be with a clean nozzle, too - no plastic dripping or caked on the end

DarthRevan 2018-06-14 12:49:37 UTC #3

We check both of those things before every print, and they are not a problem.

PaulS 2018-06-14 15:31:04 UTC #4

pic is worth a 1000 words LOL print 1 layer and post a pic and maybe we will see something. This is assuming you have already done your hot end PID tune or equivalent and extruder calibrations correct? Nozzle tightened at temp? what size nozzle and layer height?

carefudundae 2018-06-14 16:04:17 UTC #5

agree with @PaulS here, a pic (or better yet a video) would really help.
it sort of sounds like underextrusion (many many causes for this, but I'll assume the firmware and slicing settings are good), like there isn't proper tension on the extruder gear or something is pulling back on the filament... could also be electrical (I recently broke an extruder wire in the cable chain and it caused something like this, but intermittent)

DarthRevan 2018-06-14 16:14:13 UTC #6

Will try my best to get a video. We have tried adjusting the tension and it did not work (which confused us because it did before). The electrical was something we had not considered yet, that might be it.

PaulS 2018-06-14 16:20:20 UTC #7

yup could also be something to do with bed adhesion. what is the deal there? heated pei is the ideal IMHO but opinions vary...

heartless 2018-06-15 12:21:50 UTC #8

Are you doing the checks with things cold, or heated? It DOES make a difference.

Bed should be heated to the correct printing temp when checking the level as I described above.

heat will cause expansion - basic thermodynamics - what is correct when cold will not be correct when heated.

DarthRevan 2018-06-18 12:37:26 UTC #9

We check it when it's heated.

dvdsnyd 2018-06-19 17:09:43 UTC #10

@DarthRevan

What type of filament are you using?
Is it popping at all? Sounds like the problem could potentially be wet filament.

DarthRevan 2018-06-19 22:19:15 UTC #11

We are using PLA. It is not popping at all, and we thought about the wet filament, then we tried a filament that had been in a bad with a desiccant (also a PLA filament), and had the same result.

dvdsnyd 2018-06-20 13:00:13 UTC #12

Hrm. PLA is one of the least hydroscopic materials, so I wouldn't worry about wet filament at this point.
Have you had a chance to take a picture or video? This would really help diagnose.

Like others have mentioned, it sounds like under extrusion or a bed height / level problem.

Here's a simple test: If you set your nozzle further from your bed and start a print, how does the extruder react? on long extrusion runs, does it extrude a nice long thin piece of filament?

Dave

PaulS 2018-06-20 13:21:11 UTC #13

there are a few bed level tests on thingyverse but i use a 20 mm test cube and just add a skirt with 10 laps set distance so skirt is about 20 mm inside your bed all the way around. when it starts printing, i manually adjust bed height and usual have it dialed in before the skirt is done printing. once level just abort job... this is my quick and dirty way but caution to LIVE moving machinery here Hopefully you have already printed some fancy bed knobs so much easier to adjust...

dvdsnyd 2018-06-20 17:01:37 UTC #14

That's a really good idea. Could even scale the cube up a little bit if needed.
Might have to steal that one

PaulS 2018-06-20 17:28:16 UTC #15

IMHO this really helps with S3D supports on big models. i used to be plagues with support failures or rafts fusing to parts usually on just 1 side of model till i started doing this method before big prints. amazing the difference perfect 1st layers in prints make for the rest of the job!.

DarthRevan 2018-06-26 17:49:08 UTC #16

I haven't had a chance to get a video yet, we needed to print ASAP and so purchased another printer. I do not know what the fate of our old printer will be, if we try another print I will take a video.

PaulS 2018-06-27 12:14:39 UTC #17

well if you were close by to tampa, since you are a school and all i suppose i could take a look for you for free of course but no idea if you are in range to make this practical.

DarthRevan 2018-06-27 17:32:39 UTC #18

Not in range to be practical.

DarthRevan 2018-07-05 22:29:17 UTC #19

We have done some checking, and everything, that everyone we found suggested, was fine. We think that the extruder stepper motor is skipping, what are some possible causes for this.

csorrows 2018-07-06 08:06:09 UTC #20

I skimmed back over this thread and didn't see stepper driver vRef mentioned. If the stepper is skipping, it may not be tuned correctly.