Extrusion calibration

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Jules
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Re: Extrusion calibration

Post by Jules » Wed Aug 17, 2016 2:48 pm

ednisley wrote:.......it should be producing 0.45 mm threads (perhaps because that's the "automatic width" setting), then forcing a 0.40 mm width with a low extrusion multipler just starves the output.
I really do think something like this is going on now.....and that's a perfect way to describe it. The only thing I see when I mess with the multiplier now is skimpy fill in solid layers.

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NF6X
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Re: Extrusion calibration

Post by NF6X » Wed Aug 17, 2016 4:22 pm

Hmm. Well, I have Extrusion Width set to Manual, 0.4mm. I'll take a look at the Z adjustment app. Note that I did all of my leveling and initial gap adjustment cold, since quick start doesn't allow doing it hot.

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Jules
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Re: Extrusion calibration

Post by Jules » Wed Aug 17, 2016 5:28 pm

NF6X wrote:Hmm. Well, I have Extrusion Width set to Manual, 0.4mm. I'll take a look at the Z adjustment app. Note that I did all of my leveling and initial gap adjustment cold, since quick start doesn't allow doing it hot.
Yeah, I wasn't crazy about that cold-set aspect of setting the gap with the Rev.Es.

But - having said that, when i first started testing the Rev.E, I'm afraid I made a bit of a to-do with Josh and Rick, (likely ruining their weekend, and making a complete idiot out of myself in the process :lol:), because I kept insisting that they needed to do hot-sets in order to get the relative gap correct between the two nozzles on the dual. (That's what we had to do with the older machines.)

Unfortunately, I did that before I actually tested the machine to see if there was a problem....and there isn't.

Something changed in the way that they handle the gap distance in the new Rev.E firmware, and it has to do with the fact that the switch is located on the bottom for the Rev.E as opposed to the top of the Z-rod for the older machines. I can't even begin to explain it.....I wasn't in on the development. But whatever they did, it no longer makes a difference in hot-setting versus cold setting.

So for the Rev.E machines - it doesn't matter if you set it cold. Which is good, because you can't set it any other way. Keeps people from burning themselves, I guess. :lol:

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NF6X
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Re: Extrusion calibration

Post by NF6X » Wed Aug 17, 2016 5:33 pm

That's good, because I'd rather work on a cold machine, anyway. I'll turn up my infill percentage in my next calibration session and see what that gets me.

How sensitive is the print quality to extrusion temperature? I haven't noticed a significant difference between 200C and 210C, but I also haven't experimented with extrusion temperature extensively yet.

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Jules
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Re: Extrusion calibration

Post by Jules » Wed Aug 17, 2016 5:50 pm

NF6X wrote: How sensitive is the print quality to extrusion temperature? I haven't noticed a significant difference between 200C and 210C, but I also haven't experimented with extrusion temperature extensively yet.
Printing at too high a temp will damage the plastic and turn it matte, dull and "cooked" looking. Five to ten degrees swing in the center ranges doesn't make much of a difference, but print at the very lowest limit of the range, and then the highest, and you'll see a huge difference.

For PLA, since you want it to be hot exiting the nozzle and then to cool off ASAP once it exits, it makes sense to keep to the lower to middle side of the range. It reduces warping problems.

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NF6X
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Re: Extrusion calibration

Post by NF6X » Wed Aug 17, 2016 5:53 pm

Got it. I used to print at 190C with my previous printer, but its temperature calibration was so poor (I measured a 10C difference between setpoint and a thermocouple shoved down the extruder path) that I don't know what the actual extrusion temperature was under normal operating conditions.

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Re: Extrusion calibration

Post by NF6X » Thu Aug 18, 2016 5:06 pm

These photos aren't fantastic, but I hope they're good enough for you M2 experts to tell me if I'm on the right track with my extrusion calibration. I made this little 60mm square test piece to work with extrusion of flat horizontal surfaces over support. Extrusion multiplier is 0.9, temperature is 200C, and filament is the MG PLA that came with the printer. 0.35mm nozzle, 0.4mm extrusion width, 40% infill, 0.2mm layers, and 2mm support resolution. Solid layers are 3 on top, 3 on bottom, and 2 perimeters.
SupportTestPrint.png
Extrusion Over Support Test Print
I think the top surface came out pretty well. It appears to be fully filled. Does this look right?
IMG_3788.jpg
Top Surface
The bottom surface shows dense fill on the 10mm wide perimeter that printed on the scratched up PEI build surface. I left the support in place. The supported areas are stringy. My gut feeling is that this may be as good as I can expect under these parameters. What do y'all think?
IMG_3789.jpg
Bottom Surface
Can I achieve better fill of large horizontal support surfaces using single extrusion? How about using dual extrusion with either dissolvable support or something like PETG over PLA (or vice versa), using solid support?

As an aside, I can probably manage to take better pictures of my printed result details with some practice and more effort involved in setup.

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Jules
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Re: Extrusion calibration

Post by Jules » Thu Aug 18, 2016 5:47 pm

Top surface looks as good as any I've seen. :D

Your underside looks as good as you can get with those settings....it's not bad.

With a single...you can improve the underside of overhang areas somewhat, by using dense support layers (one or two) at about 60%. And i like to run the support in two directions in a cross hatched pattern. It's not quite as easy to remove, but it actually supports better.

My settings for PLA:
Support settings.JPG
With a dual - you can get it almost as solid as the top surface, by using alternative filaments for the support and zero vertical separation. Never going to be perfect, but it's a lot better than printing over a one layer gap. :D

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Re: Extrusion calibration

Post by NF6X » Thu Aug 18, 2016 5:54 pm

Thanks! Ok, I'll finesse things a bit more in single extrusion land as a learning exercise, and I'll try printing some non-PLA. But it sounds like it's almost time for me to install that dual extrusion upgrade kit.

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