Mini printing problem after software and firmware upgrade

Ages ago, my printer just stopped, and I haven’t had time to follow up for a very long time, or a need to print anything.

See Mini stopped mid-print, and now unresponsive

Well, today I had some time to restart investigating it, and something I now want to print.

So thought I’d start over with a new version of Cura (3.6.23 instead of previous 3.23) and update the firmware.

As recommended, renamed the %appdata%/cura-luzbot folder, and reinstalled both cura and the firmware update for my Mini (v1).

Probably lost the few customizations I’d made, but thought the defaults for ABS (IC3D) plastic would probably be ok. I think I’d adapted it slightly to a cooler printing temperature, but the default was 245 deg hotend, and 110 bed.

And I think I’d slightly adjusted the Z-height.

But the printing is TERRIBLE. It’s extruding far too fast, and not sticking to the heated bed properly.

How do I recover my previous settings, and why are the defaults working so badly?

Took a picture on my phone of the first layer print:

Make sure you flashed the correct firmware for your printer AND printhead combination. For example, if you have the standard print head and flash firmware for Aerostruder (or vice versa), you’ll have really significant extrusion issues.

Next up would be to adjust the Z-offset. I think later versions of Cura provide a way to do that through Cura print menu (not sure, I stopped using Cura a long time ago). But you can also do it interactively via the console in Cura, with the M851 command (and then M500 to save setting).

Sending a M503 should give you a response showing the current M851 setting. The default is probably around -1.30, depending on the firmware. If your first layer is too high, make the value slightly more negative and try again (i.e., if it is “-1.30” and printing too high, try sending “M851 Z-1.35” to move it 0.05 closer to the bed.

Beyond that, posting a video of the first layer would be helpful for further diagnosis.

Sorry for long delayed reply - other things took over in the interim.

I’ll give your suggestions a go today or tomorrow - thank you for your help.

My printer is an unmodified original Mini, with the standard print head. I’ll double check what software and firmware I downloaded, but I don’t off the top of my head think it likely that it was the wrong one.

But I’ll check the key settings.

Where would I look for the extrusion rate, which seems much too high - spewing out very fast, and spreading too far?

You can see the extrusion value (E-Steps) in the output of an M503 command. Send M503 and review the output for a line preceded by “M92”, which will then have step values for X, Y, Z, and E. For example:

echo: M92 X100.50 Y100.50 Z1600.00 E410.00

I believe the firmware default E-step value for the Mini’s original “Standard” extruder is E833.

The firmware default E-step value for the Mini with Aerostruder is E420. (I have an Aerostruder on mine, and have adjusted the step value 410 as shown in example M503 output above).

Also be sure to check the slicer’s extrusion rate – make sure it is at “1” or “100%” (not sure how Cura implements it). An incorrect value there could also cause wild extrusion.