a1 - Step motor clicking but under extruding

Spark

I don't understand this printer the a5s is nice and works great.  This a1 I think is just a lemon. The step motor is clicking and I feel the filament coming out (like it can NOT move it forward. My prints are coming up under extruded.  

Samuel Pinches

Maybe try add a drop or two of canola oil to bowden tube?

I wish they had tuned the stepper driver powers a little higher for the extruder especially, but the z axis could do with more power too.

 

chainbreaker2012

could the nozzle be clogged? is it happening at the beginning of the print or all the time?

Richy_T

I just had the same start happening myself. I've been printing a multi-part piece and I noticed it doing this on the first layer about half-way through the jobs and then later all the way through the print. Didn't think too much of it as the print still looked OK but it seems to be getting worse. I cleaned and replaced an old nozzle and same thing so I ordered some new and it's just as bad. I'm going to load up a different filament and try printing something to see if that does anything. I think it might be I should just replace the extruder motor. I've marked the gear and it seems like it happens mostly in the same place.

Richy_T

Well, here are my preliminary results... I started disassembling stuff and running fresh filament through everywhere. It ran pretty free *except* at the point where the filament enters the extruder (or at least where the little "ring" where the fitting grips it is). I trimmed it slightly before the ring, losing about two inches.

I still get some clicking if I hit the extrude button a bunch of times (on slow) so I'm thinking I may have to replace the motor anyway (I'm not sure what the part number is. It's very faint and when I try to take a picture with my phone, it washes out with the flash). I'm currently printing a 3d Benchy and the extrusion looks correct again though so I'm happy enough for now.

Richy_T

Motor has got worse. Anyone know the part number?

Samuel Pinches

IMHO the motor is the least likely thing to be wrong - more likely to be excessive friction elsewhere. When a stepper motor gets stuck, it gets really grind-ey, or doesn't move at all. If you remove the filament and it spins smoothly during an extruder command, the motor very likely not the problem.

Richy_T

I kinda agree. But I eliminated my friction issue which I'm not all-that convinced was at issue anyway. Could potentially be the driver maybe. The extruder appears to be putting out a decent width of filament. Potentially the temperature could be at issue but I raised it 10C and still get clicking even extruding freely on slow. The current print I'm trying is set for 40mm/s where I've been comfortably printing at 60 before (and the first layer prints at reduced speed too).

I ordered a replacement stepper off Banggood anyway and I'll give that a try. I might throw some canola down the tube too and maybe I'll order some fresh tube up as well.

Richy_T

It just occurs to me that I know for a fact that the extruder has been happy to grind the hobbed nut on the filament when the filament has become blocked before. That implies something other than simply friction in the post-extruder setup. That could still be the driver rather than the motor but the motor is easier to replace so we'll see.

It would be nice if there was a way to see how much force the motors were exerting on the filament. I might see if I can think of a way to measure this. These motors have known torque ratings.

Richy_T

You win this one, Pinches.

My new ptfe tube came in today. (Note: the tube in place is more than half of 5' so you won't get two lengths if you order that much. Need to get exact measurements). Since I now had extra tube, I stuck a few inches in the extruder and tried to push the filament through by hand. No go. My brand new extruder head was blocked . Luckily I had ordered a few so one swap-out later (and a clean-up of the general area) and I appear to be printing fine again. No idea what could have caused that blockage. Perhaps some junk in the filament? I've been printing from that reel for a while though.

Samuel Pinches

For my printers that run in my garage, I like to fold up a tissue or microfibre cloth, and then use a bulldog clip to pin it over the filament - a poor mans' dust brush.

Still seems odd to encounter blockages. I think its more likely to be an air gap in the heatbreak, perhaps the PTFE liner is too short perhaps?

Richy_T

Well, it's doing it again so... Brand new nozzle again too.

Talk to me about this air gap. I pushed the PTFE liner in as far as I could. I also got the new extruder tip good and tight. What should I be looking for?

Note that when I was testing with the previous nozzle, I had the temperature up to 230 and the pla was liquid on the outside of the nozzle so it should have been hot enough.

My filament really shouldn't have got anything on it big enough to block the nozzle. It's just in the spare room with nothing gritty around.

Samuel Pinches

Nozzle should be tight against the heartbreak, not tight against the heater block? The ptfe tube in heat break should be pushing against top surface of nozzle. Hope that makes sense.

Richy_T

Makes sense. Should not be the issue since nothing has moved there but with new nozzles, I guess they could be short. Anyway, stripped everything down (except moving the break in the heater block. Oops) and put it all back together with a new nozzle and printing is going well so far. I'll definitely tweak things if I have another issue or next time I have it all apart.

I think you may be right though as there was some molten pla around where the heat break threaded into the heat block. I probably just wasted my time but it will be easier next time. Unless I got lucky.

One thing I do need to know for next time is how far to screw the assembly in. I thought I got it the same but the bed levelling suggests I have it at least one turn further out than stock. The jgaurora video just shows them screwing it in with no explanation.

Richy_T

Yeah, definitely getting some leakage. I'll tear it down tomorrow. That could explain why I was getting some scorch marks in my white PLA. Leaking out of the top of the heater block and running down, maybe? It always printed fine though.