1 Topic by cckens

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Topic: 1st Real Print and a question.

OK, so I finally found time to start dialing in the settings for printing.  Switched over to Repetier and Slic3r (very simple thanks to Ian), and started to run tests.  Printed out this barrel from thingiverse (http://www.thingiverse.com/thing:32016) and the result is below.

Now the question becomes what happened.  Stuck fine to the kapton.  Bed is as level as I can get it without a gauge.  I see some layer peeling, but nothing major.  The banding has me bamboozled, though  The staves should be all the same all the way around but they lump every 3rd or so layer... not sure what's happening here.

FYI, default Repetier per Ian's instructions, newest Slic3r version (9.4 I think) with Ian's config file.

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2 Reply by IanJohnson

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Re: 1st Real Print and a question.

Check out this thread on how to remove backlash from the Z axis. https://groups.google.com/forum/#!topic … D8o1o5FG4Y

If that doesn't work, also try cooling the electronics with a fan.

3 Reply by MeshMoth

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Re: 1st Real Print and a question.

It looks like the flow rate/temperature  is too high... I noticed that each filament (from the 2 that i've used) needs different flow rates. It looks like the plastic is oozing a bit much. The green solidoodle stuff that came with my printer seemed to be harder than the spool i bought from amazon. I needed to set the temp lower and flow rate lower for the stuff that i bought on amazon than the solidoodle stuff.

4 Reply by cckens

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Re: 1st Real Print and a question.

So, Ian, the Google groups thread you posted just advocates a 5/16-18 Jam nut on the Z-axis screw to kill the backlash?  Sounds almost too simple to work, but indications seem positive.

But would this affect the whole of the print?  The print doesn't show signs of shifting, it just seems to be printing these ridges the entire perimeter of the print where the staves are in the print.

I just checked the settings and you have the config set to 5 perimeters.  Might this cause the problem?

5 Reply by IanJohnson

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Re: 1st Real Print and a question.

It might be a combination of those two things.  The nozzle tracks through the top layer point to a flow rate that is too high.  The alternating bulging layers look like inconsistent movement in the Z axis, with some layers getting squished more than others, and a high flow rate exaggerating the effect.

6 Reply by cckens

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Re: 1st Real Print and a question.

Sounds logical.  There may be some definite "squishing" going on there.

Looks like a trip to the hardware store for a jam nut to see what I can find.

Do you advocate an adhesive to hold the nut in place?  I know that you seem to have tried superglue, and there are others listed, but will it really need it?  Or will I just have to keep finger tightening the nut in place?

7 Reply by IanJohnson

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Re: 1st Real Print and a question.

You would have to keep tightening it.  My superglue came loose, so the nut twitches a little with each direction change, which probably means there isn't any correction going on.  If you tighten it down again, it's just going to work loose after a bit.  It doesn't seem to take much to keep it from turning.  I think a couple dabs of hot glue at each side would do it.

8 Reply by WhiteStar01

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Re: 1st Real Print and a question.

The backlash in my Z affected all layers (to some degree)  The first few layers would always be squished a bit more- this in turn allowed a tiny bit of corner-curl.  This would be an additive effect through the print.  Just guessing but when the nozzle would contact these- it would change the z position slightly within the lash- and propagate the problem.

A bit of flexible glue (I used automotive "Goop" and a printed cap- and the problem is 99% gone.

Cheers

9 Reply by MeshMoth

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Re: 1st Real Print and a question.

I feel this thing has something to do with this subject?

http://www.thingiverse.com/thing:34397

What is it and how do I use it??

10 Reply by cckens

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Re: 1st Real Print and a question.

Update:
I've been printing a few things in my spare time, of which there is precious little, and have discovered a few things.

1) There doesn't seem to be much in the way of backlash that's happening as I did what the google thread recommended and I pushed down then up near the Z screw.  I'm not feeling any kind of movement in that area.  So I decided to try to re-level the bed...

2) Anyone else have a bed that seems warped off the center?  I'm noticing in leveling that when I level the edges, I get the center so close to the extruder that it almost crashes.  I can hear almost a little grinding when I run the carriage over the center, which makes me have to re-level so the center is not that close to the bed, which throws off the edges.  Need to get the glass/mirror in there and see what effect that has on the prints.

3)  I ran some of the calibration tests from http://www.thingiverse.com/thing:5573.  The .5mm thin wall test ran without a hitch, though showing some banding in the layers, not as bad as the barrel test from earlier.  The 20mm solid box is supposed to be printed with 100% infill, which I set up.  When I was getting near the top, I started noticing that the layers were squashing and the box was shimmying as the layers hadn't completely cooled.  I don't have a fan for cooling the layers, so that may be what is causing this.  Not sure, but it seems the higher that the print gets, the more likely the plastic is to wobble because it isn't cooled enough. May have to adjust the bed temp or slow it down so that the layers sufficiently cool.

Comments welcome as I try to get this dialed in correctly...
Thanks!

11 Reply by IanJohnson

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Re: 1st Real Print and a question.

First print a box with 1 perimeter and no infill so you can check the thread width (0 shells in Skeinforge).  Tweak the flow rate (SF) or Extrusion Multiplier (Slic3r) until it mesures at .42mm +/- .02 or so.  If that is dialed in and the solid layers are still too full, turn down the extrusion width for infill.  You could also try turning up the nozzle diameter a little so that threads get spaced a little further apart, but that might affect the dimensional accuracy.

12 Reply by driggers

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Re: 1st Real Print and a question.

IanJohnson wrote:

First print a box with 1 perimeter and no infill so you can check the thread width (0 shells in Skeinforge).  Tweak the flow rate (SF) or Extrusion Multiplier (Slic3r) until it mesures at .42mm +/- .02 or so.  If that is dialed in and the solid layers are still too full, turn down the extrusion width for infill.  You could also try turning up the nozzle diameter a little so that threads get spaced a little further apart, but that might affect the dimensional accuracy.


+1 to this.  You'll need calipers, instructions are here https://github.com/alexrj/Slic3r/wiki/Calibration.

Basically you print a 1 layer wall and measure.  Then adjust your Extrusion Multiplier to compensate for the ratio between expected wall thickness and actual wall thickness.  This calibration saved Slic3r for me.

Also, I use Slic3r 0.7.2b primarily, because I can see more settings at the same time, as long as I don't need features of the newer one.

SD2 Sanguinololu 1.3a atmega1284p, wood platform, lawsy's carriages, braided fishing line, pallet wood overhead spool mount, carboard/magnet enclosure, glass bed, E3D v6, bed levelling knobs, extended z-stop, 25A DC-DC SSR for bed heater, everything fixed to the SD2 frame, marlin firmware with some adjustments and extra failsafes enabled.  I'll never give up on you, little printer that could(n't)!

13 Reply by cckens

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Re: 1st Real Print and a question.

OK, weekend calibration testing completed.

Results:
Glass/Mirror as the bed top is a winner!  Do need to make sure that you have enough hairspray on it.  First tests peeled off the bed during print.  Not so good.  More hairspray works as well as extra time on the bed to make sure that it's heated the glass enough for sticking.  I've got good adhesion and the layers are going down well.  Also need to make sure that I don't dial down the bed temp from 100 during the print as this seems to lead to de-lamination from the bed.

Extrusion calibration done.  Really need to try this again to make sure that I've got the multiplier set correctly, but it seems that this is not necessarily causing the banding on the print.  I still see it and it's more obvious than ever.  I'll need to run test with Skeinforge to see if it's a slic3r thing, or if I need to run with the extrusion width fix that Ian proposed.  Either way, my holiday weekend will be spent in front of the machine trying all sorts of things.  I'll recheck the z-axis screw for backlash, but I'm still not feeling any movement on it when I'm pushing/pulling on the bed near the screw... should I be using more force?  I'm just afraid of doing something to the bed that will screw it up.

Conclusion:
I've made lots of headway.  If I can just fix this banding issue, I'll have some decent prints to send to the smoother for testing on that.

BTW, anyone know if model paints (like Testers) will adhere to the print and produce a satisfactory colored result?

14 Reply by JustSomeGuyTN

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Re: 1st Real Print and a question.

cckens, I've been wondering about paint choices myself.  I have a bunch of Tamiya paint that I'm going to try.