Provide a simple measurement tool
Really? I have only barely experimented with multiple nozzle sizes, so
have no direct experience, but I would have thought that the nozzle size
would in practice constrain how fast you could feed plastic through it.
Yes the nozzle size places constraints on the flow rate but the flow rate
is determined by the rate the filament is fed into the hot end and the
filament diameter.
It also places constraints on the extrusion path width and layer height but
doesn't come into the slicer calculations other than some slicers use it to
set default extrusions widths. Generally the extrusion width is wider than
the nozzle. It isn't defined by the nozzle aperture because the plastic
cannot change in volume. The width is determined by the flow rate versus
feed rate and the layer height and the plastic spreads sideways or gets
stretched accordingly.
I usually used 0.4mm nozzles and 0.5mm extrusion paths. The slicer has to
offset inwards by 0.5mm, not 0.4mm.
On Tue, 31 Aug 2021 at 01:23, Gene Heskett gheskett@shentel.net wrote:
On Monday 30 August 2021 17:29:56 David Gustavson wrote:
@GeneHeskett The mechanical Z tolerances can't be that far off.
Somehow a wrong value has gotten put in the code relating steps to Z,
I suspect. Look at the G code's Z values!
I had to raise my temperature from about 240 to 270 after switching
from a brass nozzle to the hardened one, which conducts heat less
well. I also changed to a solid copper heat block, just on
superstition.
Do I recall you use Cura on your Prusa? Cura has some plugins I'd like
to try, but I've been afraid to use it.
Yes, I use cura on my mk3s. And just for grins I raised the nozzle temps
to 250 and 260 for the last 2 builds, 2nd one underway now. And I've
reset cura to a .22 layer after the first one. and that has come pretty
close to wiping out the extra height. So I am getting closer. And the
260C version matches the openscad z size +-.05mm. But it didn't do
anything to stop the stringing between the splines when they are pointed
inward.
There are I hope, other slicers that do bridging better, cura is not so
good at that. But other than those 2 obvious problems, seems to be
working quite well. I have the 2nd of 3 critical parts on the build
plate now, and I am hoping the layer size change will fix all 3. The two
housings are about 1mm from being completely assembled due to the
overthick parts.
We used to say when an engine blew up 70 years ago, that the pan wasn't
big enough for all the parts. ;-) Neither is this but I'm working on
that.
Take care all.
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
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On Sunday 29 August 2021 07:57:12 Adrian Mariano wrote:
Gene,
I suggest that you revisit PrusaSlicer. Just print some simple
calibration test object with the default parameters and see if it
comes out better compared to the same print on Prusa---that won't
require a deep understanding of PrusaSlicer. I wonder if you can
resolve most, if not all of your problems by switching to PrusaSlicer
and using the profiles that are specifically built to work with the
MK3S.
Following that line of reasoning, I made an adjustment to the OutputCup
to reduce its diameter by about .3mm in order to fit the other half of
the housing without resorting to some razor blade work to get the
insertion started. And I then fed that .stl to both cura and
prusaslicer.
I should have reduced the circle size of the "keys" that prevent slippage
rotation though, as the keys can be seen in the ball bearing track that
is the output bearing for this drive. Probably nothing that exersizing
the drive won't mash down, but its there in the part rendered with cura.
But now I'm about 5 layers up with the prusasliced part from the
same .stl and I must admit this part looks like a sharper, crisper
render compared to the cura part. We'll see if the keys show thru when
it gets up to the middle of the ball track, around 4.5mm up. Its also
slower by a couple hours.
If so I hate to waste the filament, but it may be time to increase the OD
of this drive by a mm to make room to better play. There is a limit to
how high I can make its top if I expect the bottom of the gantry on a
6040 mill to clear it as it passes overhead. Its intended to enhance the
accuracy of an A axis, and give it 50x the holding power of the stock
drive for this mills A axis. At zero backlash as harmonic drives are
famous for... That also means arcsecond accuracy if the belt is snug
enough.
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
On Wednesday 01 September 2021 12:39:44 Gene Heskett wrote:
On Sunday 29 August 2021 07:57:12 Adrian Mariano wrote:
Gene,
I suggest that you revisit PrusaSlicer. Just print some simple
calibration test object with the default parameters and see if it
comes out better compared to the same print on Prusa---that won't
require a deep understanding of PrusaSlicer. I wonder if you can
resolve most, if not all of your problems by switching to
PrusaSlicer and using the profiles that are specifically built to
work with the MK3S.
Following that line of reasoning, I made an adjustment to the
OutputCup to reduce its diameter by about .3mm in order to fit the
other half of the housing without resorting to some razor blade work
to get the insertion started. And I then fed that .stl to both cura
and
prusaslicer.
I should have reduced the circle size of the "keys" that prevent
slippage rotation though, as the keys can be seen in the ball bearing
track that is the output bearing for this drive. Probably nothing that
exersizing the drive won't mash down, but its there in the part
rendered with cura.
But now I'm about 5 layers up with the prusasliced part from the
same .stl and I must admit this part looks like a sharper, crisper
render compared to the cura part. We'll see if the keys show thru when
it gets up to the middle of the ball track, around 4.5mm up. Its also
slower by a couple hours.
If so I hate to waste the filament, but it may be time to increase the
OD of this drive by a mm to make room to better play. There is a limit
to how high I can make its top if I expect the bottom of the gantry on
a 6040 mill to clear it as it passes overhead. Its intended to enhance
the accuracy of an A axis, and give it 50x the holding power of the
stock drive for this mills A axis. At zero backlash as harmonic drives
are famous for... That also means arcsecond accuracy if the belt is
snug enough.
[...]
However, in 5 starts it failed to finish the build, getting 3mm or so up
in an 8.5mm build, and suddenly leaving a big lump of plastic in the
way, generating a collision crash. Readjusted the .scad to eliminate the
keys bump in the ball raceway, and cura is taking another whack at it
now. For some reason the default bed tep for petg is 100C, too hot by 15
to 20C. So cura is going to use its normal 85C, and a 250C nozzle leaves
a better ironed finish. 260C is even better, but stringing gets out of
hand then.
Cheers, Gene Heskett
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene