Extruder skipping / underextruding
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@widgetNinja said in Extruder skipping / underextruding:
Monoprice Select Plus
are you sure that your thermistor values are correct?
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@jens55 I'll test tonight and report back. Thanks for the great instructions.
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@Veti I absolutely am not!
I tried doing some searching on what thermistors they used on this, and all i could find was 'generic' information about them being 100k. New to this, but i did test that it read about 100k on my multi-meter, at about 25C.Suggestions on steps to take / Tests to perform?
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If it helps, here is a picture I took yesterday. On the brim (right word?) you can see it get thick/thin that seemed to correlate with the clicking/skipping.
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@widgetNinja said in Extruder skipping / underextruding:
I absolutely am not! I tried doing some searching on what thermistors they used on this, and all i could find was 'generic' information about them being 100k. New to this, but i did test that it read about 100k on my multi-meter, at about 25C.
Suggestions on steps to take / Tests to perform?if the settings are off, the temperature could easily be off by 40 or more degrees.
all 100k should read 100k at 25C.easiest would be to replace the thermistor with ones where you know what they are.
otherwise you need a known good thermometer. heat up water to different temperatures and note down the resistance.
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@widgetNinja said in Extruder skipping / underextruding:
If it helps, here is a picture I took yesterday. On the brim (right word?) you can see it get thick/thin that seemed to correlate with the clicking/skipping.
Looking at that brim, I have the uneasy feeling that something else is not right. The way I view things, under extrusion would generate a continuous undersized line with maybe a tad of a hiccup when it skips a step. This looks more like maybe the clearance between nozzle and bed is not quite right (too large).
In other words, you could have more then just a single issue and I would suggest trying to separate them as much as possible and testing for them individually.
I would suggest testing your extruder flow problems with the nozzle in mid air with the previously mentioned gcode lines to find out if there is skipping. Only after that is sorted would I suggest looking at the nozzle to bed distance. -
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@Veti Is there a favored thermistor to buy, that has the data tables etc? Its only a few bucks so i'll get an order in to cover my bases.
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best known ones are 104GT-2 Semitec. (used by e3d) this is prob the best choice.
you could also get a PT1000.
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@Veti Thanks!
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@widgetNinja , You can get a cheap multimeter that has a temperature probe and it might be of more value in the long run.
I have used all kinds of different thermistors and they were all equally inaccurate. None of them were out by more than plus or minus 20 degrees and most were within 5 degrees when compared to a commercial grade thermocouple and instrument.
Yes it's possible that you have a weird thermocouple but since you said it was about 100k at room temperature, I am not so sure.
A spare is always a good thing but if you are like me and order from China, you could be waiting 3 or more weeks.
I lust after a PT1000 but at $12.99 from filastruder.com it's a bit on the dear side and it is not a bead so won't fit a bunch of heater blocks. It is much more accurate but unless you have multiple printers, you don't need to know an accurate temperature. You get used to your printer with your filament and you will know what temperature you will need for your setup.
It is fairly easy to verify your thermistor as well. Measure resistance at 25C as you did, measure resistance in boiling water (don't forget to compensate for elevation, water only boils at 100C at sea level) and then plug those values into formulas available on the internet (might not even be required, I did it once and it wasn't an 'ahah' type moment) -
@Veti said in Extruder skipping / underextruding:
best known ones are 104GT-2 Semitec. (used by e3d) this is prob the best choice.
you could also get a PT1000.
This. A good thermistor is one of the best and most underrated upgrades you can do. We rely on melting thermoplastic and yet we use the cheapest random generic chinese thermistors.
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@jens55 said in Extruder skipping / underextruding:
I lust after a PT1000 but at $12.99 from filastruder.com
https://de.aliexpress.com/item/32859917151.html?spm=a2g0x.12010615.8148356.1.553c6b547efYv6
thats the one i got.
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@Phaedrux said in Extruder skipping / underextruding:
. We rely on melting thermoplastic and yet we use the cheapest random generic chinese thermistors.
While this is certainly true, given a single printer setup, you will always tweak temperature based on your particular setup, cooling, bed temperature and extruder temperature. I submit that the true temperature is pretty much irrelevant as long as you are within a plus or minus 20 degree window.
You will quickly learn that a certain brand of PLA requires a 210 degree extruder temperature even though a friend may run the same filament at 190 degrees with fine results.
With multiple printers you are better off knowing the actual temperature so as to be able to determine best temperature on one printer and then be able to run the same temperature on another printer without too much messing about. -
@jens55 I don't disagree.
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Thanks again everyone. My action items/tests for tonight:
I'll test extrusion steps/mm for extruder (with no nozzle this time)
While i have nozzle off check for blockages
I'll test existing thermistor at room temp and w/ boiling water and report back.
I presume with this information we can adjust the config file?
We didn't talk about it, but i'll validate the extruder stepper motor wiring, making sure I don't have any phase wiring issues.I'll report back after tests.
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@widgetNinja i’m using a genuine E3D hotend so the values I used are documented on the forum and E3D literarure.
The E3D settings wont help with a non E3D thermistor. -
@widgetNinja did you ever find a solution? I’m having pretty much an identical problem
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@eadiecd please raise your own thread describing your issue rather than resurrecting a 3 year old thread
