Vertical Banding Revisited

Having a problem? Post it here and someone will be along shortly to help
User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Sun May 10, 2015 8:43 am

bot wrote:That is super awesome. I hope the Rambo doesn't hiccup with the added steps on larger prints. (Are you still running a rambo?)



I read that it might be an issue on the Rambo, but I wanted to test it before installing the smoothieboard. That print was at 40mm/s, I'll try a larger print at 40 then start bumping up the speed.


3D-Print wrote:Awesome. That looks great!!! I agree it will be interesting to see a larger print.

So it really does appear to be the steppers..... such that each step results in an amplified yet slight non-linear movement at the end of the arms. This non-linear movement, or vertical banding, is greatly impacted by calibration and print speed clearly as noted in this thread.

KAS, how much of the improvement do you think was due the steppers vs. the 16 tooth pulley size? With the standard pulley, how close can you get to 200 steps/mm without getting into trouble by adjusting the microsteps or etc? Just personally, not sure about those adjustments.


Just changing the pulley to a 16t would be 100mm/s. The .9 degree stepper on 20t is 160mm/s. Granted that's all on the Rambo so it's capped at 1/16 microstepping without going to external drivers. I plan on running this setup on the smoothie at 1/32 microstepping which is 400mm/s.

Honestly, if I can run 80mm/s towards the perimeter without issues, I might just stick with Rambo. Although curiosity is getting to me.

User avatar
bot
Printmaster!
Posts: 993
Joined: Thu Sep 25, 2014 12:18 am
Location: Vancouver
Contact:

Re: Vertical Banding Revisited

Postby bot » Sun May 10, 2015 4:44 pm

I've been hearing a lot of nasty stories of Smoothieboard troubles. I'd tend to agree with you on sticking with the Rambo for now. Smoothie looks promising, but the hardware and micro-logistics (of setting it all up) are far from refined.
*not actually a robot

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Mon May 11, 2015 9:30 pm

Ran a simple circle and I'm pretty stoked about the results. This was only a 200mm circle. ( I need to figure out how to remove the polygonal crap in DesignSpark). Anyways, started at 90mm/s then jumped to 180mm/s. Tried to increase the temp but it didn't want to go above 227c. The steppers stayed about 37c after 15mins of printing. I have the current somewhat low at 145.

The camera's auto focus was going nuts, sorry about that.



200_circle test.stl
(35.24 KiB) Downloaded 25 times

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2561
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Vertical Banding Revisited

Postby Jimustanguitar » Mon May 11, 2015 11:50 pm

KAS wrote:I need to figure out how to remove the polygonal crap in DesignSpark


It's the nature of an STL file. There's no such thing as a curve because it's all triangles. You're seeing what's called faceting.

You can make DSM export finer triangles if you want. When you export to STL, click on options (right above the save button) and you can change the resolution and angle that new triangles are generated at.

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Tue May 12, 2015 7:06 am

Jimustanguitar wrote:
KAS wrote:I need to figure out how to remove the polygonal crap in DesignSpark


It's the nature of an STL file. There's no such thing as a curve because it's all triangles. You're seeing what's called faceting.

You can make DSM export finer triangles if you want. When you export to STL, click on options (right above the save button) and you can change the resolution and angle that new triangles are generated at.



I see, in sketchup you can set the number of segments and make it look smooth when designing. I wasn't even looking for it during the STL export in DesignSpark. Which makes sense now because the circle was smooth in DSM before exporting.

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Tue Jun 16, 2015 8:50 pm

I finally setup the smoothieboard and this whole time I thought it was capable of 1/32 micro stepping, but I guess that's not the case without external drivers. This is my first print on the new controller and I must say that my calibration isn't quite matching what I was capable of doing with the Rambo and a dial indicator. I'll have to work on it a bit more with the auto calibration or try my hand at manually calibrating it.

Also need to figure out the layer lines that are visible on the bottom section and how to control the nozzle lifting that's creating the seam on the lower right side. No changes have been made to Simplify3D, but the nozzle purposly pauses and lifts at that location before coming back down and starting a new layer. Maybe it's normal, just never noticed it on the Rambo.

20150616_202343.jpg

DaveBot
Plasticator
Posts: 13
Joined: Sun Oct 26, 2014 9:43 am

Re: Vertical Banding Revisited

Postby DaveBot » Sat Jun 20, 2015 10:38 pm

Hi Guys -
Great work by everyone, particular kudos to mhackney for the BandAid model!

Very interesting results with the 0.9 steppers!

A question: have any of you tested printing with 1 perimeter and zero infill? My Rostock was banding about average vs what's been shown here, but then I happened to print a 1 perimeter calibration brick w/o infill (I was checking over/under extrusion vs layer height), and lo and behold it was as smooth as the proverbial baby's bottom, with all other settings the same as before!

Doesn't quite make sense, as I don't think the banding has the same pitch as the infill grid, but I was shocked & surprised when I saw how smooth the hollow box was. Could it have to do either with accel/decel associated with infill printing, or maybe the infill deposition reheating the perimeters & making them bulge? The difference was so striking, it seems like a major clue to me.

Unfortunately, I've had my printer in pieces, putting Trick Laser arms on it, as well as a MakerHive quick-change hot end board. I've been traveling and work-stressed, so only get a few hours on a Sunday afternoon to work on it every couple of weeks. Right now, hotend adapter is miswired, so the machine is dead, hoping to be back running tomorrow, though. Not sure I'll have time to also get it recalibrate do too, but will try some test prints when I do.

Meanwhile, have any of you guys tried a 1-perimeter print with no infill? If so, what did it look like?

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Sat Jun 20, 2015 11:05 pm

DaveBot wrote:Hi Guys -

Meanwhile, have any of you guys tried a 1-perimeter print with no infill? If so, what did it look like?


Few pages back I printed a rectangle with a thin wall and no infill. It doesn't have the same effect as something with infill. You can see the 3 layer base still has the banding and it matched the object underneath.

viewtopic.php?f=37&t=7605&start=75#p62147

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2561
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Vertical Banding Revisited

Postby Jimustanguitar » Mon Jun 22, 2015 8:44 am

DaveBot wrote:A question: have any of you tested printing with 1 perimeter and zero infill? My Rostock was banding about average vs what's been shown here, but then I happened to print a 1 perimeter calibration brick w/o infill (I was checking over/under extrusion vs layer height), and lo and behold it was as smooth as the proverbial baby's bottom, with all other settings the same as before!

Doesn't quite make sense, as I don't think the banding has the same pitch as the infill grid, but I was shocked & surprised when I saw how smooth the hollow box was. Could it have to do either with accel/decel associated with infill printing, or maybe the infill deposition reheating the perimeters & making them bulge? The difference was so striking, it seems like a major clue to me.


An interesting thought... Perhaps the banding is the result of the slicer/firmware trying to achieve a specific wall thickness between multiple passes. Definitely worth testing.

DaveBot
Plasticator
Posts: 13
Joined: Sun Oct 26, 2014 9:43 am

Re: Vertical Banding Revisited

Postby DaveBot » Mon Jun 22, 2015 12:13 pm

After seeing KAS's print, I'm thinking we may really be onto something here. At first I thought his (her?) print disproved my hypothesis about interaction with infill being the problem, since the few layers of the top object would have been solid. But then I realized "duh, they just have solid *infill*!"

Perimeters are drawn smoothly, just tracing the outlines of the part, and we get nice smooth results if that's all we print.

Could the cure for vertical banding be as simple as just specifying a lot of perimeters? Would a print with, say, 5 perimeters provide enough separation between the outer surface and the infill that the laying down of the infill wouldn't affect the outer surface any more?

My machine's still down (had a bad thermistor connection after hot end mount change, now the PEEK fan's not running, & I still need to recalibrate after the arm upgrade :-/), so I can't test this myself yet, but if this isn't the answer, KAS's and my results sure look like clues. Wouldn't it be cool if we solved a problem the big boys haven't yet? :-)

Can't wait for someone to try this, or for next weekend to get here & hopefully have my machine running again so I can test it myself!

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Mon Jun 22, 2015 12:43 pm

his :)

More perimeters only seem to mask the banding effect. The speed also plays a large role in the visual banding.
To date the best "fix" is to increase the overall resolution. By either lowering the pulley size or increase number of steps per revolution ( or both in the case of the below picture)

Infill from 10% to 100% produce the same sized external banding regardless of the infill percentage. I've tested 10% infill with no top, even the internal infill has the same vertical lines in each pass. Zero infill with multiple perimeters produces it as-well



20150509_222326 (1).jpg

DaveBot
Plasticator
Posts: 13
Joined: Sun Oct 26, 2014 9:43 am

Re: Vertical Banding Revisited

Postby DaveBot » Tue Jun 23, 2015 1:05 am

Thanks for the additional info, and wow, that's a gorgeous print!

So, it seems we know these things:
- Essentially no discernible banding with perimeters only
- Any amount of infill produces it
- Extra perimeters mask but don't vanquish it
- 0.9 degree steppers and small pulleys pretty much eliminate it

I'm having a hard time coming up with a mental model for what could be happening, sure would like to figure out a good-enough solution that doesn't involve taking apart my printer coz it takes me a month of Sundays (literally) to find time to do anything.

It doesn't seem like a fundamental issue of insufficient spatial resolution, because it doesn't show up on perimeters.

The only way I can think of the infill causing it is if it's smooshing out the already deposited plastic in the perimeters.

It can't be just a heat-related thing, else the 0.9 steppers wouldn't make a difference.

So it seems it has to be an overshoot issue, where the hotend nozzle is traveling some distance into the perimeter when changing directions as it hits the perimeter area.

Can't be play in the arms, universal joints, cheapskates or belt stretch or 0.9 motors & smaller pulleys wouldn't make a difference. (UNLESS the print speed changed in the process - but it sounds like you're slowing down, just not radically.)

That leaves the steppers themselves, and I'll put another hypothesis out there: It's that whenever we have a situation where the head needs to change course abruptly, if we're also somewhere between full steps, the weaker holding power of the micro step positions isn't enough to stop the head right where we want it, so it overshoots. Places where we *are* right on a full step position, there's enough holding torque to avoid the overshoot. So we get ripples, depending on where the infill bumps into the perimeter, and where the full steps of the motors fall.

Changing to a smaller pulley not only reduces the amount of head travel per motor revolution (which should produce ripples with a shorter period), but it increases mechanical advantage, so the transient load felt ny the motor will be less, and the wimpy microstep holding torque may be enough to stop the head where we want it. I'd imagine that half as many microsteps with 2x the stator poles would give the same res but better holding torque.

What can we do short of a motor/pulley upgrade?

It'll slow printing a good bit, but I'd think cutting jerk way down would help. Can we control decel separate than accel? (Noob here) If so, set decel low but let accel (when the head will be moving get away from the perimeter after a direction change) where it was.

Sorry for all the typos, waaay tired, gotta put don the iPad and get to sleep.

User avatar
bot
Printmaster!
Posts: 993
Joined: Thu Sep 25, 2014 12:18 am
Location: Vancouver
Contact:

Re: Vertical Banding Revisited

Postby bot » Tue Jun 23, 2015 2:10 am

I'm gonna be building a delta with the following specs, as soon as the parts get here:

0.9 degree steppers on xyz

16 teeth pulleys

smoothieboard (1/32 microstepping)

as well as a bunch of other fancy untested stuff that may or may not turn out to be good. But I'm really taking your lead on this high resolution stuff, KAS. Thanks for the work.
*not actually a robot

User avatar
teoman
ULTIMATE 3D JEDDI
Posts: 1783
Joined: Sat May 24, 2014 5:43 pm

Re: Vertical Banding Revisited

Postby teoman » Fri Nov 06, 2015 6:12 pm

I wonder what printing one of these and adding them to the motors would do for resolution :)

https://www.youtube.com/watch?v=kYmUJVE6Vo0



When on mobile I am brief and may be perceived as an arsl.

User avatar
bot
Printmaster!
Posts: 993
Joined: Thu Sep 25, 2014 12:18 am
Location: Vancouver
Contact:

Re: Vertical Banding Revisited

Postby bot » Fri Nov 06, 2015 6:22 pm

This problem is 100% caused by segmentation of moves in repetier, marlin, and smoothieware. When using a duet with dc42's fork of reprapfirmware, the only small artifacts left seem to be from the extruder pulses -- the banding we see here is completely alleviated. This causes ringing to be more noticeable, but straight lines are actually straight save for small bits of extruder moire. See this photo:

IMG_6790_resize.JPG

From this thread: http://forums.reprap.org/read.php?178,509378
*not actually a robot

User avatar
Glacian22
Printmaster!
Posts: 303
Joined: Thu Apr 04, 2013 6:07 am
Location: Seattle

Re: Vertical Banding Revisited

Postby Glacian22 » Fri Nov 06, 2015 10:29 pm

WHOA, that is a dramatic improvement!

User avatar
bot
Printmaster!
Posts: 993
Joined: Thu Sep 25, 2014 12:18 am
Location: Vancouver
Contact:

Re: Vertical Banding Revisited

Postby bot » Fri Nov 06, 2015 11:08 pm

It certainly is, and it is a direct result of the way the delta kinematics and step pulses are generated.
*not actually a robot

DSteck
Printmaster!
Posts: 39
Joined: Sat Sep 05, 2015 8:34 pm

Re: Vertical Banding Revisited

Postby DSteck » Sat Nov 07, 2015 12:05 am

Damn. Looks like I need to think about switching to a Duet.

Right to Make
Prints-a-lot
Posts: 28
Joined: Thu Oct 29, 2015 2:56 pm

Re: Vertical Banding Revisited

Postby Right to Make » Sat Nov 07, 2015 12:54 am

I get this same effect. kind of annoying really but I am running rostock max, stock, no modified electronics but with E3D V6 hot end. But if you get back to basics, :ugeek: we are running stepper motors which step in degrees. They just do it so smoothly we don't notice. :ugeek: And by using a high quality hot end we effectively increase our resolution we see on our prints as stepper motor/ vertical banding. The hot end is so precise we see the steps. With increased data processing, or upgraded / modded electronics they see better results, which make sense because it effectively lets the stepper motors buffer their steps faster so it will give a more fluent step rather than just a step, step, step. :mrgreen: Its all so simple now. I paid extra to be able to print like poo. but at least i don't get any jamming. 8-)
All silliness aside, i really like the E3D nozzle but i did get a smoother outer layer print with the stock hot end, and this is why i think that is. or i just felt like talking randomly on the theory of printing plastics by electro-mechanical process by which we call, taking it to the Max, Rostock that is.

3D-Print
Printmaster!
Posts: 511
Joined: Mon Jan 05, 2015 9:39 pm
Location: Omaha, Nebraska

Re: Vertical Banding Revisited

Postby 3D-Print » Sat Nov 07, 2015 7:54 am

DSteck wrote:Damn. Looks like I need to think about switching to a Duet.


Also consider geared stepper motors for your extruder(s) (viewtopic.php?f=35&t=7011&hilit=ezstruder&start=75#p75760)

As I have time, I am planning to:

1. Change my extruder to geared steppers (in the boxs, waiting to assemble).
2. Change my motherboard to Duet (on my Christmas wish list)
3. X, Y and Z steppers to 400 step/rev with 16 teeth pulleys (viewtopic.php?f=37&t=7605&hilit=vertical+banding&start=150#p68587)
My 3D-Printing learning curve is asymptotic to a Delta's X, Y and Z-axes

derzaubererer
Printmaster!
Posts: 68
Joined: Tue Aug 25, 2015 10:15 am

Re: Vertical Banding Revisited

Postby derzaubererer » Sat Nov 07, 2015 9:33 am

wow that a printer controller has soooo much quality improvements:O

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1125
Joined: Thu Dec 04, 2014 6:06 pm

Re: Vertical Banding Revisited

Postby KAS » Sat Nov 07, 2015 11:10 am

bot wrote:This problem is 100% caused by segmentation of moves in repetier, marlin, and smoothieware. When using a duet with dc42's fork of reprapfirmware, the only small artifacts left seem to be from the extruder pulses -- the banding we see here is completely alleviated. This causes ringing to be more noticeable, but straight lines are actually straight save for small bits of extruder moire. See this photo:

IMG_6790_resize.JPG

From this thread: http://forums.reprap.org/read.php?178,509378



Damn you Bot! Ordering a Duet today.... :mrgreen:

Right to Make
Prints-a-lot
Posts: 28
Joined: Thu Oct 29, 2015 2:56 pm

Re: Vertical Banding Revisited

Postby Right to Make » Sat Nov 07, 2015 10:40 pm

Also think about rigidity. The stock hot end mount is extremely beefy, which makes it more rigid. Quite a bit more beefy than the mounting hardware you get for an e3d.

DSteck
Printmaster!
Posts: 39
Joined: Sat Sep 05, 2015 8:34 pm

Re: Vertical Banding Revisited

Postby DSteck » Sun Nov 08, 2015 9:33 am

3D-Print wrote:
DSteck wrote:Damn. Looks like I need to think about switching to a Duet.


Also consider geared stepper motors for your extruder(s) (viewtopic.php?f=35&t=7011&hilit=ezstruder&start=75#p75760)

As I have time, I am planning to:

1. Change my extruder to geared steppers (in the boxs, waiting to assemble).
2. Change my motherboard to Duet (on my Christmas wish list)
3. X, Y and Z steppers to 400 step/rev with 16 teeth pulleys (viewtopic.php?f=37&t=7605&hilit=vertical+banding&start=150#p68587)

I actually did order a geared extruder last week to help with prints when I use my 0.25mm nozzle.

User avatar
bot
Printmaster!
Posts: 993
Joined: Thu Sep 25, 2014 12:18 am
Location: Vancouver
Contact:

Re: Vertical Banding Revisited

Postby bot » Sun Nov 08, 2015 6:32 pm

KAS wrote:
bot wrote:This problem is 100% caused by segmentation of moves in repetier, marlin, and smoothieware. When using a duet with dc42's fork of reprapfirmware, the only small artifacts left seem to be from the extruder pulses -- the banding we see here is completely alleviated. This causes ringing to be more noticeable, but straight lines are actually straight save for small bits of extruder moire. See this photo:

IMG_6790_resize.JPG

From this thread: http://forums.reprap.org/read.php?178,509378



Damn you Bot! Ordering a Duet today.... :mrgreen:


Don't shoot the messenger! :lol: I had to beg my girlfriend to buy me a Duet as soon as I saw that thread -- gonna use the smoothie to make a little mill like Matthew's (travelphotog).
*not actually a robot


Return to “Troubleshooting”

Who is online

Users browsing this forum: No registered users and 1 guest