Overextrusion with calibrated nozzle


#1

The last time I had posted here my hotend had crashed through the bed which also seemed to cause some other problems as well. I was able to work through most of the problems, that I knew about and now I’m running into a strange overextrusion problem. I calibrated the extruder motor and I get consistent repeatable results when I run the extrusion command, but when I go to print something I get results that look over extruded. Any ideas what could be causing this?


#2

Starting with the basics and with something I am guilty of… have you put the correct nozzle diam and filament diam settings into your slicer?


#3

I wish it was that easy but unfortunately those settings are correct. Thanks for the suggestion though. I think something happened when it crashed into the bed, before that it was printing fine.


#4

If it was working before and now not you have to eliminate the obvious.

Is the Firmware the same? Did you accidentally reset the firmware to defaults changing the steps you thought you had set.

Is the software the same?

Is the filament old and full of moisture?

If none of these are the cause then start to look at the hotend that hit the bed.

Did you replace the nozzle? If not it could be damaged at the opening and giving you a weird result.

Is the Thermistor cracked and giving a false temp reading? Maybe running too hot.

Is the Heater loose giving inconsistent heating?


#5

Can you post a screen shot of your slicer settings?

I can imagine anything resulting from a crash causing over extrusion.


#6

The only thing that was changed was I replaced the PICA board with a new one. I am not totally sure if the previous board was bad but I was getting strange results when the previous board was installed and that is also when it crashed into the bed. The firmware is the same and I double checked the settings to make sure that the extruder was calibrated. I am using a hardened steel nozzle so I doubt that it was damaged during the crash. How would I check if the thermistor is bad? It seems to heat up very similar to how how it used to. Thanks for all the tips to check out, hopefully I can get this ironed out. Here are some screenshots of my slicer settings:


#7

To check the thermistor you need something to measure the hot end separate to the machine like a multimeter with a temp probe or another thermistor to test.

The Z axis Movement Speed set to 100mm/s is way to fast. Try setting it to between 10 and 20mm/s and see how you go. I wonder if you are skipping steps in Z and it’s printing layers over the next without moving up in Z.


#8

The skirt looks alright to me, so the skipping z steps might be it.

Edit: have you adjusted vref on your stepper drivers?


#9

I tried messing with the vref but that didn’t help any. What did work was when I reduced the speed, not just Z but X and Y also, now it is printing great but at a slower speed then before. I’m not sure why this is, sometimes I think this printer is possessed. Thanks for the help though.


#10

Cool good job. Yeah most Cartesian 3D printers of this size are about 50 to 80mm/s for X and Y and 10 to 20mm/s for Z


#11

I had troubles with over extrusion, and 2 things that fixed the problem.

  1. my Z shaft couplers had worked loose because I had not used Locktite,
  2. In the firmware there’s a function that modifies the extrusion rate according to the speed of the extrustion.
    Check out My struggles with over extrution

What I had found was the default firmware is defined to use 2.85 mm filament and I was using the Willson Standard 1.75
This caused slow extrusion to work perfectly fine but when using higher extrusion rates it over extruded. I included pictures and I think you will find similarities.

Best wishes.