Extruder seems to stop outputting randomly
April 17, 2017 06:04PM
Hello everyone, I am brand new to the world of 3D printing. I have not long ago put together my first one which I ordered from eBay. I have not been able to get through a whole print since I got it. Randomly during a print the extruder looks like it just gives up, this could happen right at the beginning, usually happens by the 7th or 8th mm layer. I can tell when its about to happen as the motor starts clicking, then a few seconds later no more comes out. I found that I can push the filament through a bit to get it back to working for about half a minute. I have tried just telling it to extrude and that seems to work fine. I have seen a solution on the forum, people saying to increase the tension or something but I am not sure how to do that, I have searched google to no avail. Maybe I'm looking for it wrong? Any help would be appreciated!

I have an unlisted YouTube video showing how it just gives up, the point it stops is at the 3:30 mark.
https://www.youtube.com/watch?v=cyvt5u0UvUA
Re: Extruder seems to stop outputting randomly
April 17, 2017 08:37PM
Have you calibrate the extruder steps per mm?
Also have you calibrated the extruder motor driver current?
Direct drive extruders like that seem to skip steps a lot. It will sound like clicking.
Re: Extruder seems to stop outputting randomly
April 17, 2017 10:21PM
I just tried calibrating the Esteps, but any change I made just yielded random results. One little change and it would go from 38mm (100 expected) to 72mm. I tried putting it a little higher and it went down to 20mm. I have watched various videos on people doing to exact same thing as me yet it just doesn't seem to work. As for the motor current, I have no idea how to adjust it. I looked at the wiki and the identification section for "Melzi" looked completely different from what I have.
Re: Extruder seems to stop outputting randomly
April 18, 2017 08:30AM
Does the motor driver look like this?
A4988 Driver

This is the most common driver.
Can you take a picture of the control board?
Re: Extruder seems to stop outputting randomly
April 18, 2017 08:39AM
One thing to note, it could be a time vs temp issue. When I run PLA (200C), I can print at 45-60mm/s, but when I run PETG (245C) I can start at 45mm/s but it'll stop extruding like your experiencing. However, when I run PETG (245C) at 30mm/s I don't have any issues with the material not extruding. In my case, the temperature profile is fine, but PETG just takes a little longer time to melt properly than PLA and the course of the print I can see the stoppage after 3-4 layers. This is just one example of other outside forces that can replicate your issue.

Running a higher temperature might also be a correction.
Re: Extruder seems to stop outputting randomly
April 18, 2017 08:56PM
Sorry for the late reply guys, had some finals at my college to take care of today.

Floyd:
My motor driver's seem to look a bit different (other than the color)



PDBeal:
I have tried between 180C and 220C in 10C intervals, and it changed the output but also seemed random. The thing is though that it looks like it just stops all together, instead of missing a part here or there. Is it safe / a good idea to go any higher than 220C ish?
Re: Extruder seems to stop outputting randomly
April 19, 2017 05:44AM
My experience is that idlers are often far too loose. Tighten that idler tight. You need to find out how to adjust your motor current so that it turns and pushes filament through at a reasonable hot end temp but not so high current that the motor gets very hot (60 deg C or lower is okay, unless your motor mount is pla) the motor should skip/click if there is a jam rather than grind the filament which is the filament slipping on the drive gear (or hobbed bolt).

It's finding the balance but general rules like tight idler and modest motor current will get you going in the right direction. Extruders like titan/bondtech etc... Are often easier to setup well, they are more standardised and better documented.

Whilst there is an argument about how effective they are those drivers normally have heatsinks on the driver chips. If the current is quite high the driver chip overheats it shuts itself off for safety, the motor stops turning, it will come back on when it's cooled down. Get a fan blowing over the drivers, maybe measure the temperature of the extruder driver when the fault happens.

You don't need to go above 220 for pla, 210 really, you need a thermocouple thermometer to check that the hotend is actually heating to the temp you think it is, thermistors are accurate but only when setup correctly they are not necessarily giving you the actual temperature unless you've verified it. Ir thermometers are not great but can be made more useful by painting one side of your hot ends heater block in black high temp paint, (or sharpie marker). Don't presume anything works unless you checked it yourself.

Edited 3 time(s). Last edit at 04/19/2017 09:49AM by DjDemonD.


Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Re: Extruder seems to stop outputting randomly
April 20, 2017 03:58PM
I had the same problem. Turned out it was the motor cable being faulty. Try wiggling your extruder motor cable during printing and see so that it doesnt stop
Re: Extruder seems to stop outputting randomly
April 20, 2017 04:08PM
Quote
Hatmpatn
I had the same problem. Turned out it was the motor cable being faulty. Try wiggling your extruder motor cable during printing and see so that it doesnt stop

If you have an intermittent extruder motor connection then you run the risk of destroying your motor driver. There is a very good reason they say not to disconnect the motors when powered up, there can be very large voltage spikes which destroy the chip, a loose wire creates that same problem. Check the cables by powering them off and testing them with a multimeter, wiggle them for sure but don't do it with the machine powered up, unless you have spare driver boards lying around.


Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Re: Extruder seems to stop outputting randomly
April 27, 2017 03:45PM
I have had a similar problem, but worse. I tested my cable and there are no shorts. And I even wriggled the cable, per your suggestion. I have a RepRap Prusa i3 and I recently upgraded the extruder and hot end to E3d v6 and E3D Titan. All was going well when one day the extruder motor appeared to stop working. It actually did not stop completely, but began to twitch, turning neither forwards or backwards, which locked up the Arduino/Ramps 1.4. I swapped motors, same problem. I tested the cable, swapped motor controllers, a spare Ramps board, and finally replaced the whole Arduino/Ramps 1.4 assembly. And I tried turning the Ramps motor controller potentiometers up and down. No luck. Does anyone have any idea what would make a motor twitch and lock up the system, given that I have replaced everything, and some parts more than once? My original Arduino Mega 2560 was replaced with a Version 3, and the RAMPS 1.4 board was probably a bit of an upgrade too. [It is a very good thing that this stuff is not expensive!].

Secondly, and I hate to use the word "coincidentally," but my MatterHackers 12v hot end heating element is in question. Whenever I turn the hot end on the RAMPS 1.4 board starts flashing an amber light furiously and does not stop, but the heater heats up just fine. My prior board... and I think it was the Arduino Mega rather than the RAMPS, flashed a red error light. I checked the wires going into the heater element and found there was some white powdery stuff protruding, which I scrapped off. It was something like the fuzz you get when a battery goes bad. I tested the heater for resistance and it showed 1 ohm. I called MatterHackers and asked them what the resistance was supposed to be and the tech guy said he did not know. Any ideas? BTW, Should I post my questions in a separate, new post?

Thanks
Re: Extruder seems to stop outputting randomly
April 27, 2017 05:04PM
I just watched your You Tube video and added a similar response. First, it appears your print speed is much too fast. My prints would fail catastrophicly if I tried to print that fast. I have made a few prints that look like your video. I have a Prusa i3 and it has been a good work horse (until lately). I am in the process of diagnosing it at the moment, but when it was running for the last 3 years I had very limited success printing at more than 35mm per second. 3D printing takes a long time. It can't be forced. I don't remember the exact details, but when I tried to run too many mm/second on my printer, my extruder freaked out, got clogged, filament got stringy, skipped teeth on the hobbed gear, stuff like that. Also it looks like the gap between your hot end and your print is too wide. I have found, as is the conventional wisdom, the first layer must be perfect or else your prints will fail rather miserably. I don't have a sensor, so I adjust the clearance for my first layer by hand. I generally set it at 6 or 8 thousandths of an inch. I think your clearance is too much, which is why your first layer and the skirt are zig-zaggy and the layers won't stick together. If you lean your head over and look at the print head while it is printing the skirt and first layer, the hot end has to lay the plastic down almost exactly on top of the first layer; you can't give the plastic any "air time." You will lose precision and temperature. Also, if your hot end actually touches the first layer (I call that dragging it through the mud) your first layer will be ugly and damaged. It will take several layers to work the ugly out of the mud-dragging. Your print might finish ok, but the bottom will still be ugly. Lastly, the steps per mm for the X,Y, and Z axis must be calibrated with as much precision as your machine will allow. And, did I say lastly? Lastly the potentiometers on your motor controllers must be adjusted correctly. When I first got my printer running all of my prints leaned toward the back of the print bed. Adjusting steps per mm did not help. The solution was to crank up the Y axis motor controller's potentiometer. After I boosted up the Y axis potentiometer my prints were perfect vertically [although the motor started getting hot so I had to put a fan on it]. Adjusting the potentiometers is an exercise in trial and error, and be sure to turn off the power, unplug your USB cable, and use a plastic screwdriver. I found that grinding the end of a plastic chop stick into a screwdriver works great. After you set your hot end clearance to the bed, slow your mms per inch, make sure your nozzle is perfectly clean, etc., you might just start getting some very good prints! Please do not be discouraged! When I first assembled my 3D printer I had no idea how many hours I would work on it and learn, and work, and learn, before I was satisfied that it was calibrated as well as the machine would allow. Nuff for now. If I start talking about squaring up your frame your head might explode.

Edited 8 time(s). Last edit at 04/29/2017 03:32PM by drgrs.
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