layer height for .25 nozzle

[tmo]

what layer height should i be aiming for with the .25 nozzle?

just set up a new brutstruder with the .25 and looking to get the
highest resolution that i can

any tips for layer height, speed etc? i can run my bot at about 55
speed no problem. at 60 it sometimes skips. my motors can run at
about 190 before stalling.

thanks

[Jordan Miller]

for highest resolution you will eventually want to slow down, in theory. i would just run through spacexula's calibration files again.

jordan

[ddurant]

I've been thinking about just that lately - how nozzle size (or
extrusion size anyway) impacts a profile. It really seems like it
should have an big impact and I've always assumed it does but I can't
think of many actualy reasons why. I'm beginning to doubt that it
really does.

With a DC extruder, a smaller nozzle will probably mean more load on
the extruder which will slow it down some. Aside from that, I think
most of your existing (or other peoples existing) profiles might be
pretty close.

Have you tried just tossing a profile you made for a different nozzle
at it and seeing how it behaves?

Anyway, in general, once you have a profile working decently, you
can't just change the layer height and have it still work - you've got
to poke one (or more) of the other big settings, too. If you drop the
layer height, you'll need to do some combination of:
- decrease flow rate
- increase feed rate
- increase w/t

You best bet is to clone some existing & easy-to-print profile and get
that working. Then clone that one (or take good notes of each
combination of settings that worked), drop the layer height by 0.05 or
0.025 and get it working. Keep doing that until you reach your target.

You've got a limited amount of tweaking you can do to feed rate, flow
rate and w/t. Once you've run out of tweak room, you're at the highest
resolution you can get.

[tmo]

thanks i will give that a try.

i think slowing down only really applies to a stepper extruder. the
difference between 190 and 255 is really not all that much and by
moving the platform faster with a consistent speed extruder will in
theory stretch out the filimant and effectively make a higher
resoluton/ smaller layer height print. the only real llimitation to a
makerbot is that DC motor on the extruder.

i just got hit with some makerbot gremelins. suddenly my z stage is
not moving as fast as it once was (its no longer binding from my
heated chamber experiments) and for some other reason absolutely
nothing is sticking to the platform even with brand new tape. I might
have to let it rest in a box for a week to recuperate..

i cant wait to get my hands on a few of the steppers that makergear is
selling. as soon as they are available i need to get my hands on at
least a few to move from these dc motors for good.

[ddurant]

> the
> difference between 190 and 255 is really not all that much

It's 25%!! If your goal really is to see how low you can go, that 25%
will definitely come in handy. Once you start getting under 0.20mm
layer height or so, you're probably not going to have much choice -
you'll start running out of room to tweak other params and will need
to drop the flow rate.

Another important bit to remember is that w/t is a ratio.. If you use
1.5 w/t on a 0.3mm layer height, your thread width is 0.45mm. If you
use 1.5 w/t on a 0.20mm layer height, your thread width is 0.30mm. If
you're dropping layer height down as low as you can, the max thread
width is going to be a critical value to know.

With the kind of hardware we're using, you could not, contrived
example, reasonably print with a thread width of 10cm - the nozzle
just isn't capable of doing that sort of size. I'm not sure what the
max usable widths are for different nozzle sizes/designs but this is
indeed a function of the nozzle. Finding the max usable width on your
nozzle will help you a lot on the road to resolution nerdvana.

Also, I wasn't saying there's no difference between a 0.25mm nozzle
and a 0.5mm one. Or any other size. The point was only that flow rate
is sorta independant of the nozzle size - flow rate is how quickly the
plastruder is taking plastic IN, not about how quickly it's coming out
the nozzle. If you switch nozzles but leave the flow rate the same,
the volume-per-time of plastic going through the system doesn't really
change (except for the side effects of adding load to the motor).

> > > thanks- Hide quoted text -
>
> - Show quoted text -

[Koen Kooi]

On Wed, Dec 1, 2010 at 7:10 PM, ddurant <ddur...@gmail.com> wrote:

> the
> difference between 190 and 255 is really not all that much

It's 25%!!  If your goal really is to see how low you can go, that 25%
will definitely come in handy.

It's not really 25%, since you also loose a lot of torque, so PWM isn't linear and 210 PWM at 220 degrees C is different from 210PWM at 195 degrees C due to the force needed to push it thru the nozzle.

regards,

Koen





 

[ddurant]

Absolutely right. It's somewhere less than 25%. But even if it was
only 5%, it'd still be worth mentioning. I'd use fewer !!!'s (like
"5%!" instead of "5%!!1!") but it'd still be worth it if you're trying
to get layer height down as low as you can.

Pushing any of the big settings to its limit is basically just pushing
all the other big settings to their limits. Once you're at the extreme
of any 3, you're also at the extreme of the 4th. (ignoring things like
temperture, which shouldn't be ignored)



On Dec 1, 2:30 pm, Koen Kooi <k...@beagleboard.org> wrote:

> > > - Show quoted text -- Hide quoted text -

[Karl Gustav Rutz]

I just got running with a .25, and I tried a layer height of .18 first. It's printing well. I've got my flowrate set very low (I'm running with a stepper extruder), and a feedrate of 26. pic of final product here: http://www.flickr.com/photos/moleofproduction/5323006376/

[Rick Pollack]

That's a very nice print! Which firmware and such are you using?

[Karl Gustav Rutz]

I'm using Rob's EC firmware 2.5 with a compact stepper extruder + Pololu stepper controler set to 1/16th stepping. Mods to my Cupcake include: Mendel-inspired bearinged lowrider x/y, and Z wobble arrester, but I still have more wobble than I'd like on taller prints. However, in the attached photo the walls look worse than they are because the imaged is squashed a bit from lens distortion.

The model I used was the very nice Fuller Lock Pulley, carved in Skeinforge 35 (I think)--not the RepG bundled version. It took about 45 minutes to build, which is a LONG build time for an object that size, but damn it turned out nice. The build was run from an SD card.

I've had a lot of trouble building Mendel pulleys, but I managed to make a nice set using a .35mm nozzle. I figured they would be the perfect test for the .25 nozzle. My test extrusion stripped at a flowrate of 10, but seemed to run smoothly at 5 once I raised my temp, so I used that as a starting point. I tuned my Skeinforge settings on a .35 nozzle, and I've found that I usually have to change flowrate, layer height, and width/thickness ratios when I switch nozzles.

Skeinforge parameters:

Comb & Widen: on

Carve:

Layer Thickness (mm): 0.18

Perimeter Width over Thickness (ratio): 1.4

Temperature: all @ 230, HBP @ 120

Speed:

Add Flow Rate: True

Bridge Feed Rate Multiplier (ratio): 1.2

Bridge Flow Rate Multiplier (ratio): 1.0

Duty Cyle at Beginning (portion): 1.0

Duty Cyle at Ending (portion): 0.0

Feed Rate (mm/s): 26.0

Flow Rate Setting (float): 5.0

Orbital Feed Rate over Operating Feed Rate (ratio): 1.0

Perimeter Feed Rate over Operating Feed Rate (ratio): 1.0

Perimeter Flow Rate over Operating Flow Rate (ratio): 1.0

Travel Feed Rate (mm/s): 25.0

Clip:

Clip Over Perimeter Width (ratio): 0.05

Maximum Connection Distance Over Perimeter Width (ratio): 10.0

Cool:

Slowdown

Minimum Layer Time (seconds): 17.0

Fill:

Extra Shells on Alternating Solid Layer (layers): 1

Extra Shells on Base (layers): 1

Extra Shells on Sparse Layer (layers): 1

Infill Begin Rotation (degrees): 90.0

Infill Begin Rotation Repeat (layers): 1

Infill Interior Density over Exterior Density (ratio): 1.0

Infill Odd Layer Extra Rotation (degrees): 90.0

Grid Rectangular True

Infill Perimeter Overlap (ratio): 0.2

Infill Solidity (ratio): 0.22

Infill Width over Thickness (ratio): 1.32

Solid Surface Thickness (layers): 2

Loops > Perimeter > Infill

Fillet:

Bevel True

Corner Feed Rate over Operating Feed Rate (ratio): 1.0

Fillet Radius over Perimeter Width (ratio): 0.3

Reversal Slowdown Distance over Perimeter Width (ratio): 0.5

Use Intermediate Feed Rate in Corners True

Stretch is on w/ defaults

[Rick Pollack]

What's also nice, when the firmware incorporates the filament retraction you'll be able to take your printing to another level!

[Tony Buser]

On Tue, Jan 4, 2011 at 12:37 PM, Rick Pollack <ri...@makergear.com> wrote:

What's also nice, when the firmware incorporates the filament retraction you'll be able to take your printing to another level!

I really like that in the 5D firmware and using Dimension in Skeinforge to set the retraction.  So much nicer than fighting with oozebane and I turned off comb.