Extruder "stuttering" when printing raft


#1

I have noticed my extruder motor stuttering when printing the raft. By stuttering I mean it is backing up momentarily and then forward again several times a second. I can hear it, and see the feed cog doing it. It only does it on the first layer of raft, and only in certain positions on the platform (mainly on Y positions towards the operator from center, and near the center in X). You can see that the first layer of raft is not uniform, being light or not present in this area where the stuttering occurs. The subsequent layers of raft are complete, and it does not happen during prints. It is really pretty strange, hard to understand why that would be done on purpose, and equally hard to propose why it would happen as a fault.

Anybody else seen this?

The platform is level.


#2

it sounds like your bed is not level or you have a bunch of buildup of plastic under the platform that’s making it have high spots when the tip gets close to the bed it has a hard time pushing the plastic out and it skips the feed motor


#3

Be is level and cursory check with straight edge it looked pretty flat. But removed and checked carefully there is a little bump in the area of concern, and a somewhat worse depression in the area of the center silver patch (where Z is established). Considered together they make a change in Z of probably 0.5 mm or more going in the Y - direction. 

Got it apart now - not much ABS under that area so maybe just the perf board is a bit warped. Will try the bending trick.

Can I use acetone on the aluminum plate without removing the finish? Instructions say "wipe with cloth" which won't do much. 


#4

Tried to enter support form but it will not let me proceed "Serial Number not valid". Rechecked serial number twice. Box matches what is reported on the display.

Removed the perf board, cleaned it, bent it per instructions. There is a local high spot in -Y from the center, and a local low spot in the center. If I put a 15 cm straight edge across X, there is a barely noticeable gap at the center (perhaps 0.05 mm). With the same straight edge across Y, there is approximately 0.2 mm gap measured with feeler gages in the center. The high area is where the raft problem occurs. Since the datum is set at center, at the bump the perf board is 0.2 mm closer to the extrude nozzle. Bending the perf board changes it in a smooth arc from edge to edge, but did not affect this local area. I have not attempted to check it while heated. Auto calibration reports good.

You can clean the aluminum plate with acetone.


#5

A little bit of clicking in some areas during the first layer is not a major issue - it means your first layer is getting well-pushed onto the board and into the holes ;) This is the whole point of having a raft, after all - to compensate for non-levelness of the build surface. Once the raft is done, you have a surface that is trammed to the nozzle regardless of irregularities of the platform.

If it really bothers you, you can put a sheet or two of aluminum foil over the height sensing area(s) at the start of the print, and/or wipe the board with acetone just before printing starts to help soften up the plastic that's in the holes.

I tram my M200 build platforms by first moving the head around manually and getting it approximately trammed by eye, then I run a large print and watch carefully as the first layer is put down, adjusting the screws "on the fly" for fairly constant thickness across the platform. Generally results in little or no clicking.


#6

I have the same problem.

When doing the raft, or when it is extruding more material, extruder sometimes makes clicking sound, and gear on extruder is skipping. On that occasions there is less material extruded.

It is like the ABS is not evenly round or thick and extruder can't push it in, or there is too much space between gear and roller in extruder..

Is there any setting, that I can do?


#7

I have the same problem.

When doing the raft, or when it is extruding more material, extruder sometimes makes clicking sound, and gear on extruder is skipping. On that occasions there is less material extruded.

It is like the ABS is not evenly round or thick and extruder can’t push it in, or there is too much space between gear and roller in extruder…

 

Is there any setting, that I can do?

Quoting @Julia Truchsess again:

“A little bit of clicking in some areas during the first layer is not a major issue - it means your first layer is getting well-pushed onto the board and into the holes :wink: This is the whole point of having a raft, after all - to compensate for non-levelness of the build surface. Once the raft is done, you have a surface that is trammed to the nozzle regardless of irregularities of the platform.”

Best Regards


#8

I have the same problem.

When doing the raft, or when it is extruding more material, extruder sometimes makes clicking sound, and gear on extruder is skipping. On that occasions there is less material extruded.

It is like the ABS is not evenly round or thick and extruder can't push it in, or there is too much space between gear and roller in extruder..

Is there any setting, that I can do?

During raft is no big deal, as previously discussed. During print it is a problem of course.

Basically, anything that impedes extrusion can cause this clicking. It can be

  1. back-pressure from the nozzle due to partial or full nozzle clog
  2. back-pressure from nozzle too close to the platform or print
  3. tension on the filament from the spool (spool jammed on holder)
  4. jamming of the filament in the feed path between feed gear and nozzle (filament too fat)

Most common I think are #'s 1 and 2. A lot of times we think our nozzle is OK but actually there is a buildup inside and a fresh nozzle will help with many problems.


#9

Ok, just wondered if it was normal and expected. Sounds like not necessarily expected, but normal. 

When you say you move the head around manually, you mean push it by hand? 


#10

When you say you move the head around manually, you mean push it by hand? 

Yes. Use the firmware to get the platform up to within a mm or so of the nozzle in the center, then with the power off, move around X-Y tweaking the knobs until distance is pretty constant everywhere just by eyeball. Sometimes you have to move Z a little bit up or down during the process - the closer the nozzle is to the platform, the easier it is to see the distance.


#11

Firmware only moves in 5mm increments? Is there another way to move up down? Turn the ball screw I guess...


#12

Firmware only moves in 5mm increments? Is there another way to move up down? Turn the ball screw I guess...

Yeah, turn the lead screw by hand with the power off. Per Zortrax, skin oils can cause eventual corrosion on rods and lead screw, so gloves are recommended.


#13

Mine is doing it when just feeding filament into the nozzle feed.  Unit is only 2 weeks old.  I find it hard to believe it's ok.  Is there some kind of nozzle maintenance necessary?  Where would such instructions be found?  I like paper, not pixels on a screen,. :)


#14

If it clicks during print I would also make sure that the drive gear teeth on the extruder stepper are clean.

After some clicking it will end up being filled with filament remains and needs a thorough cleaning.

Any click that you hear will leave some remains on the drive gear causing in turn more clicking.


#15

In case anyone hasn't said so already...

I get a much better result with auto platform calibration if I clean the exterior of the nozzle and the contact pads on the perfboard with acetone before I start.

If it bumps hard on contact I feel it's more likely it didn't make a good contact and the leveling procedure is less likely to be accurate.

I get clicking in the first layer occasionally too, just as long as it doesn't continue through the print it's ok if it's not excessive.


#16

Ok - after a good 24+ hour soaking in Acetone and reaming with supplied 0.4mm wire, no more problems.  Still hard to understand how a 2 week old unit would experience this -  :shrug:


#17

Ok - after a good 24+ hour soaking in Acetone and reaming with supplied 0.4mm wire, no more problems.  Still hard to understand how a 2 week old unit would experience this -  :shrug:

It really pays to have a couple of nozzles soaking permanently in a little jar of acetone. Then you can just swap one straight over if you have a problem.

Cleaning nozzles is just a part of the deal with 3D printing, can happen on the first day....best learn how to do it.


#18

The extruder motor on our M200 at work started stuttering yesterday. It does it randomly, no matter which position on the platform and it results in an incomplete raft and a defect print.

At first I thought, that the nozzle is clogged. So I cleaned the nozzle and the whole hotend until no filament was remaining. I tried to print again and the result was the same as before. Unfortunately the points of stuttering are completely unpredictable.

That´s why in this case the back pressure from the nozzle is not plausible. I also disassembled the stepper motor to check the small bearing and if the stepper itself has some spots where it is rough-running. But everything seemed ok. I also twisted the ribbon cable a little bit during extrusion with no effect to the behavior of the stepper.

I guess the stepper got damaged somehow due to heat. The printer was equipped with side covers (top still open), the material was Z-Ultrat, software-version 1.1.0 and firmware 0.0.5 and in another try 0.0.7.

Any suggestions what could be the reason?


#19

Steppers usually don't loose power by themselves, they either work or don't work.

I would suggest:

- measuring filament diameter on a few spots (1.8mm or more is problematic while laying rafts; up to 1.85mm works somewhat while printing)

- cleaning of the teeth that grab the filament (usually after hearing the clicking noise once then the teeth already need cleaning!)

- filament roll drag, the roll should spin very easy while printing raft. Some drag is ok while printing.

- try another roll of material (I saw some bad batches of ABS from different manufacturers that expand like foam when heated)


#20

Hi,

When I was using build plate V1, its height  was often uneven (confirmed in the calibration result) , because of some material parts going threw the holes, and I experienced clicking noises during raft printing. Performing the recommended maintenance tasks was helpful. I have much less problem with build plate V2 but it might help too.

Laurent