Looking for help with calibration of E

I found the folder in the path: Computer/C/Users/Jeff/.skeinforge/profiles/extrusion/PLA

jeffwilson Wrote:
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> So I confirmed that my feedrate and flowrate are
> the same, both are 16.
>
> I changed my packing density from .85 to 1.0
> because I am using PLA for calibration and
> printing.
>
> I confirmed and fine tuned my steps per unit in
> marlin to have 10mm of filament feed into the
> extruder assembly when asking for 10mm to feed in.
> When I select 60mm per minute feed rate it takes
> 10 seconds, when I select 30mm/min it takes 20
> seconds.

Sounds like its calibrated well enough to start.

I went through your profile and found a few things that may be the culprit.

First in "carve"
Layer Thickness (mm): 0.4
Perimeter Width over Thickness (ratio): 1.8

0.4 x 1.8 = 0.72mm

This would make it seem like a lot of material is coming out but it would be correct if you have a large nozzle. If you have a small nozzle you will want this to = the nozzle diameter while keeping a width over thickness of at least 1.5.

So for 0.5mm nozzle you would want a layer of say 0.35 and a width over thickness of 1.6 to = 0.48mm wide thread.

Second is chop which I have no idea what it does. I use SF40 and SF44 which don't have it. Maybe some one else will clarify things

Quote
chop
Format is tab separated chop settings.
_Name Value
WindowPosition 600+0
Open File to be Chopped
Add Extra Top Layer if Necessary True
Add Layer Template to SVG True
Extra Decimal Places (float): 2.0
Import Coarseness (ratio): 1.0
Layer Thickness (mm): 10.0 This looks really high but as I said I don't know what it does.
Layers From (index): 0
Layers To (index): 999999999
Correct Mesh True
Unproven Mesh False
Perimeter Width (mm): 2.0 This looks really high but as I said I don't know what it does.
SVG Viewer: webbrowser

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Sublime, I'd like to thank you for all that valuable information.

You removed some false ideas I had accumulated, reading around or guessing about skeinforge settings :
- I thought flowrate should be left at the default 210 and never touched when using dimension.
- I believed Perimeter Width over Thickness was something you measure, not that you can choose.
- I had no idea about packing density needing to be changed for PLA.

No that I have tried your advices, it lead me to realise that my E_STEPS_PER_MM are actually steps per tenth of a mm, and I'm starting to get on my way of getting a real calibration done instead of guess work.

Chop does not show up in my settings page as an option, so I'm not sure what it does either. I changed layer height from .4 to .35mm and width over thickness from 1.8 to 1.6 as in Sublime's post, and it showed a lot of improvement, the feed rate is noticably more on target with what I know it should be. It lays down a steady bead that when purged into air, and the diameter is .47mm on average. I printed a nickle calibration object, 5 layers thick. I measured the distance traveled in Z with calipers against a clamped block for each layer of the print. I found an average of 0.34mm of movement per layer, which I think is close enough for now.

During that print I noticed a alarmingly fast buildup of more and more plastic per layer (still way better than where I was at in previous posts). I think the .35mm per layer needs to increased. The first layer was very good, had clear definition between infill lines, had a pretty decent outline. The second was also good but the lines were much thicker, the third was nearly solid infill where the lines bled into eachother, the 4th and 5th layers had the extruder building up plastic against the surface as it skimmed the top of the prior level.

My question now is how to adjust the layer thickness. I measured .47mm extruded filament thickness into air. I setup the perimeter width over thickness equation from the SF41 "?" help button page and from the above post.

.47mm / 1.6 = layer thickness = 0.294mm.

This value is smaller than my current thickness of 0.35mm so I think I'm doing something wrong. Is my .47mm the wrong value to plug into the formula?

The free air diameter no longer matters. Don't even bother to measure it. That was pre SF 40 only.

Did you adjust the width in "Fill" as well?

For the z height you could use the scale plugin to adjust it until you find what is correct and then scale your Z steps per mm in the firmware based on your findings.

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Quote

The free air diameter no longer matters.

It doesn't affect calibration but it does set the maximum filament size that you can extrude while still stretching it. If you extrude filament with a bigger cross sectional area it has to be compacted lengthwise, so it will sag and zigzag whenever it tries to span a gap (for example where infill is sparse).

The maximum layer height with 0.47 filament will be about 0.375mm with W/T = 1.5. I would use 0.35mm as a little stretch is beneficial. You can go lower but eventually it is stretched too much and it will tend to snap when bridging and also cut corners. Then you have to increase W/T from 1.5 to get thinner layers and by keeping W no less than the nozzle aperture diameter you can make T as low as you want.

Edited 1 time(s). Last edit at 11/10/2011 04:41AM by nophead.

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[www.hydraraptor.blogspot.com]

Another thing to remenber : any time you change your W/T ratio, don't forget to also adjust the W/T in the Fill tab !

I have been able to successfully print several objects now with z scaling at 1.25 and the layer height seems to be good for the plastic adhesion to the layer below. The objects were skewed in z axis, 25% too tall. I turned scaling off and increased layer height by 25% to .4375 and now it seems to work pretty good. I'd like to tweak this to be smaller, but it runs and so far I am satisfied with the results.

I still have a lot of fine tuning to do, but I'm much better off now. A sincere thanks to everyone that took the time to help me.

Hi, I too have a problem with setting the extruder speed and, while I have followed this thread, I haven't managed to cure the problem. I'm running Marlin via Pronterface from the 'Kliment-Printrun-82aa15b' download. I can't see anywhere what version of Skeinforge is installed with this but, when I try to set flowrate down from its default 210 to 30 which I have as feedrate, it won't allow me to set it below 50.
I am very new to 3d printing and completely confused by all the possible permutations in the software - even the 'simple' SFACT. I tried to find the settings file which JeffWilson posted so I could attach it to this message but all that appeared to be in that directory was a file called 'temperatures.csv' .
My machine is a Prusa Mendel with Wades extruder and the hot end has a 0.4mm nozzle. The symptoms of my problem is that, as in JeffWilson's case, the extruder is running way too fast and skidding on the PLA filament. During the past print attempt I did change the value in the Pronterface Extruder speed box from the default of 300 to about 12 and, after a while, presumably when the arduino buffer refreshed, the extruder speed did drop but, if I'm going to have to juggle settings in both Skeinforge and Pronterface, that is getting even more confusing. I will say that I am not a complete novice at this type of thing as I have hung around the EMC2 community since it was first developed and have a couple of home built milling machines running successfully on that platform but this whole 3d printing game seems far more complicated.

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Thanks, Ian

I am away from my PC for the holiday, when I get back I will comb this thread again and see if I can find any places that remind me of where you are at now. In my pronterface i think I can set my flow well below 50. If you look back in the thread about where I found the PLA profile to zipped it to upload, it should have lots more files than just that one. Try a search from your start menu (if using windows) for the extension type or a few key words, mine was NOT where I expected it to be on my PC. Also, are you experiencing these problems during a manual move, or during printing? Have you made any changes to your firmware? What electronics do you have?

This project seemed hopelessly confusing to me for longer than I'd like to admit, mostly because it was (and still kind of is) so far above my level of knowledge. But over the past year I have grown so much in my ability to troubleshoot software, document everything, and to recognize that learning happens slowly. I have learned an incredible amount about so many things, but it took forever and was hard. Trust in the forums and be patient. Work and perseverance (and help here) will eventually get your machine working. Good luck and I'll try to se if I can think of anything else when I get home in a few days.

Thanks Jeff, I have now moved my queries to here [forums.reprap.org] so that I didn't clutter up your space.. I did manage to change the extruder speed by manually typing the value into Skeinforge but it didn't seem happy!! I have, however, had one decent print from the machine - not perfect by any means but distinct progress - however, I now have a different problem in that the extruder has started running backwards and completely unloading the filament just before it starts a print.....Dohh!!!

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Thanks, Ian

Haha! Mine does that too! I've been getting everything warmed up, purging some filament, then closing and re-loading pronterface quickly just before starting each print. Somewhere in my geode it's set to 'home' E to the position to whatever location the program starts up in. If I print or manually extrude, any movement pre-software reboot is reversed ejecting my filament. I've used the workaround reboot but eventually I'll tackle the root cause. If you find the fix let me know

Read this thread: [forums.reprap.org].

No need to quit pronterface to zero the extruder. just type G28 E0 in the command window and send it before printing. Or add it to start.gcode file in the alterations folder of Skeinforge.