1 (edited by 2n2r5 2013-09-14 13:12:32)

Topic: Moire - Might not always be in the printer

I just finished swapping out my extruder stepper with a high resolution .9º stepper. Couple this with the 1:32 stepper drivers that I have gives me over 400 steps/mm. On flat wall prints I have insane print quality. No artifacts show other than the infill which show as faint dark lines in the first picture. However, curved surfaces always tended to show moire that I thought was from extruder pulsing. After taking a second look at the STL and design, you see that the curved surfaces show small lines that resemble extruder induced moire. That is the result of most 3D modeling programs using polygons as circles so you circles are not round. This post is just to get the idea out there. I'm not saying all of it is due to the stl quality. I am trying a couple other slicing programs as well right now as well as some high resolution models. Hopefully I will find something that clarifies this once and for all!

http://2n2r5.com/pictures/printer/show-n-tell/moire_test.JPG
http://2n2r5.com/pictures/printer/show-n-tell/vase_moire.JPG
http://2n2r5.com/pictures/printer/show-n-tell/vase_moire1.JPG

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

2

Re: Moire - Might not always be in the printer

Impressive print quality. I get some crazy moire even on flat walls. Looks like 1/32 stepping is the way to go to clean that up. I'm looking forward to hearing how your searches go!

3

Re: Moire - Might not always be in the printer

Can't wait for the guide to make this mod!  I certainly want that..

4 (edited by 2n2r5 2013-09-15 02:27:55)

Re: Moire - Might not always be in the printer

Here is a design that has almost 1 million faces. The STL was 184 MB. There is moire but it is very faint and shows only in the back of this print and only on one particular area. This is a lot different from the artifacts found on my heart vase.

http://2n2r5.com/pictures/printer/show-n-tell/tiki_gnome1.JPG
http://2n2r5.com/pictures/printer/show-n-tell/tiki_gnome2.JPG
http://2n2r5.com/pictures/printer/show-n-tell/tiki_s3d.JPG

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

5

Re: Moire - Might not always be in the printer

you are probably going to run into resolution issues with the X/Y axes as well... running a direct drive like the Solidoodle results in a fairly low step count/mm. currently the stock solidoodle has 88 steps/mm using the 1/16 drivers. on curved surfaces that will probably be visible if you zoom in enough.

moving to 1/32 drivers and fine tuning the driver current might help, but at that point I think we are pushing the limits of what is realistically possible with this level of hardware. the slop in the belts is probably around the same magnitude.


of course a low poly STL will give the same effect as well...

6

Re: Moire - Might not always be in the printer

Yes, Teach me!

7 (edited by 2n2r5 2013-09-17 19:27:20)

Re: Moire - Might not always be in the printer

downeym wrote:

you are probably going to run into resolution issues with the X/Y axes as well... running a direct drive like the Solidoodle results in a fairly low step count/mm. currently the stock solidoodle has 88 steps/mm using the 1/16 drivers. on curved surfaces that will probably be visible if you zoom in enough.

moving to 1/32 drivers and fine tuning the driver current might help, but at that point I think we are pushing the limits of what is realistically possible with this level of hardware. the slop in the belts is probably around the same magnitude.


of course a low poly STL will give the same effect as well...

I do run DRV8825s all the way around already. I think the toothed belts would cause more issues. It might be time to try cable drive.

One thing that everyone should know is that I am running .25 nozzles with .3mm walls @ .15mm layer heights so I will see more issues on my prints then I would at the default heights and widths. I also take pictures at the right angle to show the problem which makes it look worse that it actually is.

I would love to think that we are pushing the limits but I feel like there is still a little bit more that we can squeeze out of it. Might try a geared stepper also. We can't be done until I get WYSIWYG!

Stevos758 wrote:

Yes, Teach me!

see list below tongue

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

8

Re: Moire - Might not always be in the printer

Again, I dont think that is bad at all.. I think thats about as good as you could ever hope for with this level of mechanics!

That looks like a very well tweaked printer. Care to share a list of mods?

9

Re: Moire - Might not always be in the printer

I think the only important mods are Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, DRV8825 drivers, Overkill Y-idlers, Extruder fan , and .9 degree extruder stepper motor.

The first 2 are the most important IMHO. The glass bed is a no-brain-er. You can't have a good print without a good flat starting surface. I think everyone here has done that.

The threadless z setup is something that I haven't been championing enough. Partly because it requires due diligence when putting it together. You have to make sure you test it out side of the machine to ensure that it has enough holding force. Otherwise, you could install it and have your bed not move at all. I know some people recently started the mod but I haven't heard any feed back. As far as quality goes, no other mod can bring your machine as close to its max operating specs. It is the only way to ensure that your X-Y accuracy is the only limiting factor for layer positioning. Any thread can and will show eventually in your print. Period.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

10

Re: Moire - Might not always be in the printer

Where did you get your stepper?

Phidgets Inc?

Powder coated steel enclosure, 1/4" Surface grounded hardened aluminum plate, MK2A Heat bed, .200 Polished fused quartz plate, Machined quick change hot bed mount, E3D hot end, Ramps 1.4, DRV8825 stepper motor drivers

11

Re: Moire - Might not always be in the printer

techbuilder2175 wrote:

Where did you get your stepper?

Phidgets Inc?

This is mine...
https://www.sparkfun.com/products/10846

Others that you can choose.
http://www.wantmotor.com/ProductsView.a … amp;sid=80

I don't really recommend this mod though since it gets rid of the active cooling. You might be okay with a smaller motor than the one I got. I'll leave that as an exercise to others. I used a heatsink on the back of mine for now and am looking at other possible active cooling solutions.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

12

Re: Moire - Might not always be in the printer

You could always water cool your stepper motor

Powder coated steel enclosure, 1/4" Surface grounded hardened aluminum plate, MK2A Heat bed, .200 Polished fused quartz plate, Machined quick change hot bed mount, E3D hot end, Ramps 1.4, DRV8825 stepper motor drivers

13

Re: Moire - Might not always be in the printer

I bought it I had to do it lol
I always follow your mods
Anyway I'm going to send you the metal version of the thread less ball screw
for all your help to this forum.

I really appreciate it

Powder coated steel enclosure, 1/4" Surface grounded hardened aluminum plate, MK2A Heat bed, .200 Polished fused quartz plate, Machined quick change hot bed mount, E3D hot end, Ramps 1.4, DRV8825 stepper motor drivers

14

Re: Moire - Might not always be in the printer

There will be plenty of room for a fan on that motor once it is part of a dual bowden setup.   In the meantime, why not put the fan on top of it?

15

Re: Moire - Might not always be in the printer

techbuilder2175 wrote:

I bought it I had to do it lol
I always follow your mods
Anyway I'm going to send you the metal version of the thread less ball screw
for all your help to this forum.

I really appreciate it

That's awesome! I can't wait to see it. How's it working for you so far?

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

16

Re: Moire - Might not always be in the printer

I haven't completed it yet I just ordered the material and the tooling this week

I've been taking the printer apart non stop anyway, so I haven't had the chance to really play with it since I keep updating everything.

I should have something up and running by next week and I'll send you yours when I receive the material and the tooling.

Powder coated steel enclosure, 1/4" Surface grounded hardened aluminum plate, MK2A Heat bed, .200 Polished fused quartz plate, Machined quick change hot bed mount, E3D hot end, Ramps 1.4, DRV8825 stepper motor drivers

17

Re: Moire - Might not always be in the printer

IanJohnson wrote:

There will be plenty of room for a fan on that motor once it is part of a dual bowden setup.   In the meantime, why not put the fan on top of it?

It was either that or create a duct that would draw air across the heatsink into a blower fan and use that for the extruder fan. (suggested by adrian)

I don't have a blower fan ATM though. So a 40mm fan on top is most probable.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

18

Re: Moire - Might not always be in the printer

Can you point me in the direction to some pics of your setup? Is there any mods needed for the new stepper or is it plug and play(besides firmware settings?)

19

Re: Moire - Might not always be in the printer

Stevos758 wrote:

Can you point me in the direction to some pics of your setup? Is there any mods needed for the new stepper or is it plug and play(besides firmware settings?)

I won't be able to get you pictures until the weekend probably but there isn't much to see. It is a direct replacement for the stepper motor already there. Just longer and now without a fan.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

20 (edited by 2n2r5 2013-10-06 01:03:46)

Re: Moire - Might not always be in the printer

After doing everything that one could do to eliminate moire caused by the extruder stepper motor I started looking at other factors. I looked through a bunch of prints from other printers and noticed that even at its best, my printer was having trouble matching some of the big dollar printers. One of the biggest differences was how the bed was supported. Every other high dollar printer seems to have a wider support structure or the bed is supported from 2 sides.

Before: This is my basic print at .15mm layers @ .3mm Wall width. I generally run around 60mm/s for a standard print. I also have X-Y jerk turned up to 30mm/s to take advantage of my bigger steppers and stiff spectra line drive.
http://2n2r5.com/pictures/printer/show-n-tell/moire_corners.JPG
http://2n2r5.com/pictures/printer/show-n-tell/moire_corners2.JPG







After: .15mm layers @ .3mm Wall width at 75% feedrate and 20mm/s X-Y jerk.
http://2n2r5.com/pictures/printer/show-n-tell/moire_fixed.JPG
http://2n2r5.com/pictures/printer/show-n-tell/moire_fixed1.JPG
http://2n2r5.com/pictures/printer/show-n-tell/moire_fixed2.JPG

The difference is very noticeable. Slowing down the print and reducing the X-Y jerk muted the ripple substantially. You can see that corners are no longer followed up by a deep ripple. All other moire is all but gone. Not only am I happy with this print but I am done trying to get better quality. The only upgrade that would help me with quality is a bed support system for the front.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

21

Re: Moire - Might not always be in the printer

Is that Filastruder filament? It looks too white for ABS natural.

22

Re: Moire - Might not always be in the printer

I'm like 70% sure that it is my filastruder filament. I think the auto white balance on the camera did that. The back ground should be a bit more yellow than it is.

I'm going to go ahead and say it is.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

23

Re: Moire - Might not always be in the printer

What is the X-Y jerk tuning?

24

Re: Moire - Might not always be in the printer

Excellent thread, thank you.

25 (edited by 2n2r5 2013-10-06 16:16:45)

Re: Moire - Might not always be in the printer

johnforeman wrote:

What is the X-Y jerk tuning?

edit: see Tim's comment


There isn't a tuning option really. You can just alter the value in the Firmware EEPROM Configuration. I would suggest not changing the default value unless you are comfortable with it.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.