Nozzle diameter impact on Extrusion multiplier

[hdlbq]

Hello,
I tried printing on my Makergear M3 with a 0.5 nozzle.
Tuning the hot end heigth works fine, since the MakerGear software deals with various nozzle diameters.
But as soon as I tried printing my own models, it fails always, by underextrustion. Even if I specify the right nozzle diameter to Simplify3D.
It seems that specifying the nozzle diameter is not enough. I have to change the extrusion multiplier.
It is a weird thing if it is true.
May you help me on this point ?
Thanks
Regards

[airscapes]

I use multiple nozzle size all the time with my Makergear M2. I am also using an older version of S3D which I don't think matters as I also use Prusaslicer with the same Extrusion Multiplier.
With extrusion width you have to take into account the actual thickness of the filament you are using. Most filament I use meausures about 1.70 - 1.73 average and I set the diameter in the Other Tab to that average.
The other thing that affect it is the extrusion width. I DO NOT use auto, I set to a range depending on what I am printing but rull of thumb is .4 to .5 larger than nozzle. So makergear default of the .35 nozzle is .4, with a.5 nozzle I use .55, with the .75 I use .8 Not auto
With a given plastic once your extrusion multiplier is set correctly there should not be much change. Always check by printing a single layer square amd making sure your threads are attached to each other.
I did notice that my normal .92 -.93 Extrusion multiplier used with all 3 nozzles needed to drop to .91 when I used PLA with I don not normally use.
So to answer your question, you should always check Z offset and extrusion multiplier when you change filament or nozzle until you have documented your settings and get to know how thing work with your particular machine and filament.

For the first year I ran on the under extruded size as I wail making miniatures, when I started making mechanical parts, proper extrusion multiplier was more important for accurate size and strength, and what the part looked like mattered less.

Good luck and take notes!
Attached is .4mm square to print at .2mm height to view how your threads are adhered.

One side affect of a fixed width is that sometimes you will bet a blank line where the space is too thin, and other times a wide thread shoved in a gap that is too small. I live with that as Auto has never worked well for me. V4.01 S3D

Also when the attached square is printed it should be 4mm tall+- .02, this is checking your Z offset

[20181105ok]

The other thing that affect it is the extrusion width. I DO NOT use auto, I set to a range depending on what I am printing but rull of thumb is .4 to .5 larger than nozzle. So makergear default of the .35 nozzle is .4, with a.5 nozzle I use .55, with the .75 I use .8 Not auto

Hi @airscapes Thank you for your great comments!

As an S3D user I also think that the extrusion width should be around 1.2 times of the nozzle diameter. Your choice seems to be ~1.1 times of the nozle size. But I have a friend always sticking to the belief that the extrusion width should be equivalent to (or slightly less than) the nozzole diameter. Hope to have your comment on this! Thank you!

[zemlin]

I print with nozzles ranging from 0.2mm to 1.0mm (not an an M2). While extrusion multiplier might change for different setups, I do not need to account for the nozzle change with the extrusion multiplier. It's always around 1.0, give or take.

You may need to slow your print speed with a larger nozzle, as the hot end needs heat 2x the plastic for a .5mm nozzle over the MG standard .35mm.

[20181105ok]

You may need to slow your print speed with a larger nozzle, as the hot end needs heat 2x the plastic for a .5mm nozzle over the MG standard .35mm.

Hi @zemlin

In my experience, a large (0.6+ mm) nozzle ofren allows larger layer height, but the speed need to be slowed down. The net result is often lower resolution and almost the same print time. I'm curious about why you still want to use a large nozzle.

Thank you!

[zemlin]

In my experience, a large (0.6+ mm) nozzle often allows larger layer height, but the speed need to be slowed down. The net result is often lower resolution and almost the same print time. I'm curious about why you still want to use a large nozzle.

Thank you!

That is not my experience. When required, the slow down does not offset the larger layer height and extrusion width. On a larger part that does not require fine detail I can get substantial reductions in print time with larger diameter nozzles. I sometimes increase nozzle temperature to achieve the required flow rate. I also find parts printed with a larger nozzle are often significantly stronger than the same part printed with a smaller nozzle.

[20181105ok]

When required, the slow down does not offset the larger layer height and extrusion width.

This seems to need some careful balance.

I also find parts printed with a larger nozzle are often significantly stronger than the same part printed with a smaller nozzle.

If you care more about the mechanical strength, a large nozzle is definitely the best choice.

Thank you for your comments!

[zemlin]

This seems to need some careful balance.

It's going to depend on how much power you have on your hot end, and could be impacted by PID tuning.

[airscapes]

I have not seen a response from the OP..