extrusion settings on infill

General discussion topics
Dale Reed
Posts: 376
Joined: Thu Apr 10, 2014 1:39 am
Location: Cleveland Heights, Ohio USA

Re: extrusion settings on infill

Post by Dale Reed » Sun Apr 20, 2014 6:10 am

Mount PrintMore wrote:Why is it important to set the filament parameters in the FFF? What about the extrusion process is handled differently from a mathematical perspective if you set a filament diameter and extrusion multiplier in the slicing parameters versus using the override at run time? This is a question I've posted before at somepoint and the responses I got at the time led me to believe this wasn't an issue.

I tend to run copies of the same files over and over or in various colors, so I very much like not having to recreate my gcode files just because I put on a new roll. I literally run these calibration parts, take the measurements, write the override I want to use on the side of the spool with a Sharpie, and then swap around spools at will while running off various parts.

I'll get some pictures of the test patches and post them soon. Perhaps that will help spur some further discussion.
Mount P.,

Your question prompted me to "shut up and do the test". So I took a model, sliced it with my usual extrusion multiplier (0.94), then ONLY changed the extrusion multiplier (this time to 1.10) and sliced again, and compared selected regions of the two G-code files. Here are some snippets from right at a layer change:

ExtMult = 0.94:

Code: Select all

; layer 48, Z = 9.58
G0 X76.37 Y98.13 F12000
G0 Z9.51 F1200
G1 E-0.05 F1000
G92 E0
G1 X76.37 Y126.13 E0.9192 F3150
G1 X104.63 Y126.13 E1.8469
G1 X104.63 Y118.13 E2.1095
G1 X108.37 Y118.13 E2.2323
G1 X108.37 Y127.241 E2.5314
G1 X116.63 Y127.241 E2.8025
G1 X116.63 Y118.13 E3.1016
G1 X124.37 Y118.13 E3.3557
G1 X124.37 Y156.87 E4.6275
G1 X105.63 Y156.87 E5.2426
G1 X105.63 Y126.87 E6.2275
G1 X75.63 Y126.87 E7.2123
G1 X75.63 Y98.14 E8.1555
G0 X75.63 Y98.13 F3150
G0 X76.37 Y98.13 F3150
G92 E0
G1 E-0.6 F1000
G0 X115 Y130.869 F12000
G1 E-0.05 F1000
G92 E0
G1 X114.644 Y130.886 E0.0117 F3150
ExtMult = 1.10:

Code: Select all

; layer 48, Z = 9.58
G0 X76.37 Y98.13 F12000
G0 Z9.51 F1200
G1 E-0.05 F1000
G92 E0
G1 X76.37 Y126.13 E1.0756 F3150
G1 X104.63 Y126.13 E2.1613
G1 X104.63 Y118.13 E2.4686
G1 X108.37 Y118.13 E2.6123
G1 X108.37 Y127.241 E2.9622
G1 X116.63 Y127.241 E3.2796
G1 X116.63 Y118.13 E3.6296
G1 X124.37 Y118.13 E3.9269
G1 X124.37 Y156.87 E5.4151
G1 X105.63 Y156.87 E6.135
G1 X105.63 Y126.87 E7.2875
G1 X75.63 Y126.87 E8.4399
G1 X75.63 Y98.14 E9.5436
G0 X75.63 Y98.13 F3150
G0 X76.37 Y98.13 F3150
G92 E0
G1 E-0.6 F1000
G0 X115 Y130.869 F12000
G1 E-0.05 F1000
G92 E0
G1 X114.644 Y130.886 E0.0137 F3150
The only difference in the generated G-code appears to be in the E (extrusion) axis numbers. The Xs and Ys are identical. So, I guess I have to agree with you. As far as SLICING goes, dinking the extrusion multiplier ONLY changes the extrusion, not the "tool path" in X, Y and Z.

So, as far as I can tell from this simple experiment, you are absolutely right: no, it doesn't appear to make any difference whether you adjust the extrusion multiplier when slicing or online with the knob in the machine control panel. But that's assuming what the online override does. Sorry, I'm not THAT good a C programmer to pick through the firmware and figure out what the M-code for the extrusion multiplier override actually does!

Touché.
Dale

Toby
Posts: 330
Joined: Wed Apr 09, 2014 9:44 pm

Re: extrusion settings on infill

Post by Toby » Sun Apr 20, 2014 7:46 am

and in case anyone is wondering, the ratio of the extrusion amounts in the different gcodes is indeed exactly 1.10/.94 = 1.1702, at least for the half dozen or so I checked.

User avatar
jimc
Posts: 2888
Joined: Wed Apr 09, 2014 11:30 pm
Location: mullica, nj
Contact:

Re: extrusion settings on infill

Post by jimc » Sun Apr 20, 2014 12:20 pm

Dale, I would think that changing the ext multiplier would only change the extrusion and not the tool path in any way. I am curious though how or if its possible to compare what s3d outputs and what the firmware outputs when adjusting with the jog wheel? Can that even be done? Do you think s3d and the firmware would come up with the same result if s3d was set at at 1 ext multiplier with the jog wheel at 110 and s3d with an ext m at 1.10.?

Lateralg
Posts: 138
Joined: Mon Apr 14, 2014 8:21 am

Re: extrusion settings on infill

Post by Lateralg » Sun Apr 20, 2014 4:48 pm

The answer to this may be contained in the info posted above, but I'm uncertain about what to conclude.

Does the dial setting for extrusion or travel affect Gcode generation?
For example, if I set extrusion dial to 110% during print A, and don't re-set it to zero before slicing print B, does the Gcode for print B include the 10% increase?
Gary
Make Better Things
Make Things Better

jsc
Posts: 1863
Joined: Thu Apr 10, 2014 4:00 am

Re: extrusion settings on infill

Post by jsc » Sun Apr 20, 2014 5:11 pm

I had a little poke around in the firmware. M221 is the code being sent by the extrusion override dial. This sets a variable extrudemultiply, which is then multiplied into the number of steps to extrude, so yes, mathematically it is doing the same thing.

To get back to the original concern, some pictures would be nice to see what you are talking about. Travel moves leaving tracks in the top layer without z-lift on retract are common, and may not be a cause for concern.

Lateralg
Posts: 138
Joined: Mon Apr 14, 2014 8:21 am

Re: extrusion settings on infill

Post by Lateralg » Mon Apr 21, 2014 4:10 pm

jsc wrote:I had a little poke around in the firmware. M221 is the code being sent by the extrusion override dial. This sets a variable extrudemultiply, which is then multiplied into the number of steps to extrude, so yes, mathematically it is doing the same thing.
Do you know if it will send that M221 at the start of a new print?
Gary
Make Better Things
Make Things Better

jsc
Posts: 1863
Joined: Thu Apr 10, 2014 4:00 am

Re: extrusion settings on infill

Post by jsc » Mon Apr 21, 2014 4:42 pm

I presume, but don't know. Try running a print with verbose on and you will see everything that S3D sends.

If you want some more detailed help, I suggest sending a factory file with accompanying photo of how it looks coming off your printer. I would be happy to try it myself and see if it comes out better.

Lateralg
Posts: 138
Joined: Mon Apr 14, 2014 8:21 am

Re: extrusion settings on infill

Post by Lateralg » Mon Apr 21, 2014 11:42 pm

jsc wrote:I presume, but don't know. Try running a print with verbose on and you will see everything that S3D sends.
Terrific. I learn something new on the way to learning something else. Thank you,
Gary
Make Better Things
Make Things Better

Post Reply