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Well, butter my backside and call me a biscuit!

Days spent printing little calibration squares over the last few months! (I'm going to look at the bright side - it was a very good learning experience.)

Jules wrote:Days spent printing little calibration squares over the last few months! (I'm going to look at the bright side - it was a very good learning experience.)

You don't have to agree with me. . . it's just an opinion. Or a hunch. Or something.

Tim wrote:

Jules wrote:Days spent printing little calibration squares over the last few months! (I'm going to look at the bright side - it was a very good learning experience.)

You don't have to agree with me. . . it's just an opinion. Or a hunch. Or something.

Not a bad hunch as it turned out - i completed my testing and all the PETG was close enough to live with too. I still need to get better calipers - i consider anything within 0.02 mm to be good, and PETG is a little harder to get an exact number on, since it flexes just a bit. The PLA is firmer, and tends to be more exact.

If I needed something with exact tolerances to fit a specific place - I'd dial it in of course, but aside from testing specialty filaments, I'm probably not going to bother with it anymore. If i get a funky print, I'll dial it in.

(And i'm currently trying to keep my brains intact in my skull - I was about 30 seconds away from saving a rather detailed profile, and it crashed S3d. Lost the two hours of work that went before it too - it doesn't save when it crashes.)

Back to work......sigh.

Tim wrote:some people get a bit obsessive about dialing in these numbers

That would be me, I suppose... [grin]

A good value for the filament diameter gets you almost all of the way to the goal. Contemporary filaments (seem to) have much more consistent diameters these days, so the measurement isn't nearly as fussy as it once was and, if you're not fussy, the nominal diameter should be Close Enough.

The Extrusion Multiplier provides a first-order correction for everything else, from material properties to the filament drive gear to the nozzle diameter tolerance. With that number set, the actual thread width should stay close enough to what the slicer expects over a reasonable range of all the other variations. Given good filament and the M2's mechanical stability, the slicer's default Extrusion Multipler should be Close Enough.

The nozzle-to-platform distance for the first layer seems to pose the most trouble, because folks can't measure (or believe!) the 0.2 mm difference between no extrusion (because there's no gap!) and no adhesion (because there's no contact!), with various maladies lying in wait within those limits. Worse, that applies over the entire expanse of the platform and requires far too much manual fiddling to get both the offset and alignment right. Automagic distance-and-alignment sensors should eliminate that hassle and, perhaps, nobody will ever (need to) measure anything again.

Unlike you folks, I chuck up one roll of filament, do my ritual dance, and then run with the same settings for months on end: create solid models, slice 'em, Fire the M2 Cannon, and It Just Works Every Time:
http://softsolder.com/2015/09/04/thinwa ... er-images/



Obligatory XKCD:
https://xkcd.com/1479/

I can feel my knowledge becoming obsolete: that's a Good Thing!

ednisley wrote:
I can feel my knowledge becoming obsolete: that's a Good Thing!

Wrong!

Knowledge is never obsolete - it is the foundation of the pyramid. Without the cornerstone, there can be no structure built upon it.

(Okay, back to your regularly scheduled programs.....)