War against ripples So I have ben trying to get rid of this terrible rippling effect on my prints: [img]http://i.imgur.com/iyOGROh.jpg[/img] [img]http://i.imgur.com/u4ARkAW.jpg[/img] It is not very bad but I want to eliminate it. When I declared war against the ripples I was using DRV8825. So I have tried the following thus far: 1. Putting the DRV8825 in fast decay mode. Result: Small improvement 2. Changing DRV8825 with A4988. Result: Same as DRV8825 in fast decay mode, overall better than the original state 3. Changing the A4988 with another set if A4988 - just to be sure that the ones I got are not defective. Result: No difference. 4. Increasing the Vref of the stepper drivers. Tried different values for the motor current between 0,7A and 2A. Result: No difference. So I left the A4988 and started troubleshooting the speed, acceleration and jerk settings. After spending days trying out different combinations of settings (XY jerk between 1 and 15, acceleration between 100 and 3000 mm/s^2, print speed between 40 and 80 mm/s) I found very little difference between different print settings. Acceleration above 900 mm/s^2 and XY jerk above 15 result in small visible increase of the rippling effect but everything below that makes even less difference. Layer height doesn't considerably influence the rippling as well.. Both pictures above are printed at 0,1mm layer height. It does get a bit better at 0,2mm but the effect remains clearly visible, especially when printing larger models. In total desperation I tried swapping one of the stepper motors (had one spare) but this didn't help at all. What else is there to try? Other than that I do not have any print quality issues. Can the rippling effect be a result of backlash in the system? Even if it could, the GT2 belts I am using for the X and Y axis are supposed to be practically "backlash free". Maybe a hardware issue with the printer mechanics? If necessary I could post pictures of my setup. It is a mendel-style printer based on [url=https://s3-eu-west-1.amazonaws.com/3dhubs/s3fs-public/MendelMax%202.jpg]Mendelmax 2.0[/url] Please give me any ideas. Am I expecting too much of FDM in general? Maybe someone who has perfected his machine could print the model I created to test the ripples and post some pictures.. it uses just about 2g of filament. I have attached the model, please don't forget to scale it at 200% to get the dimensions I have been using (approx. 44x24mm) Many thanks to anyone willing to help! https://reprap.org/forum/read.php?1,757017,757017#msg-757017 Fri, 16 Oct 2026 02:15:07 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,757017,776216#msg-776216 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776216#msg-776216 MechaBits General Mon, 03 Jul 2017 21:36:11 -0400 https://reprap.org/forum/read.php?1,757017,776215#msg-776215 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776215#msg-776215 I work for a hi-tech company and we have top of the line 3d printers. The ones that shoot plastic still produce this rippling mainly around sharp corners and horizontal holes.If it was a simple problem you would think the high end manufacturers would have figured it out. I did not try the reduction on the extruder but did use various drivers and microstepping with no change. Its been over a year since I did all this but was ultimately left with the feeling that the rippling comes from how the moves are executed in the software. Im pretty ignorant in that area but thats the only thing that made sense to me after trying so many different things and not being able to completly eliminate it.. If I ever decide to pursue this further I will try a reduction on the extruder mainly to confirm it isnt a hardware issue.]]> Bill Clark General Mon, 03 Jul 2017 21:23:15 -0400 https://reprap.org/forum/read.php?1,757017,776130#msg-776130 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776130#msg-776130
Quote
DjDemonD
Have you seen this [www.ebay.co.uk] expensive but I've been thinking of trying it.

Looking at it up-close I think that irregularity of the tooth shape and lower friction due to fiberglass may add backlash lower repeatability.]]> newbob General Mon, 03 Jul 2017 12:30:53 -0400 https://reprap.org/forum/read.php?1,757017,776124#msg-776124 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776124#msg-776124 www.ebay.co.uk] expensive but I've been thinking of trying it.]]> DjDemonD General Mon, 03 Jul 2017 11:47:05 -0400 https://reprap.org/forum/read.php?1,757017,776102#msg-776102 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776102#msg-776102 DjDemonD General Mon, 03 Jul 2017 07:36:43 -0400 https://reprap.org/forum/read.php?1,757017,776100#msg-776100 Re: War against ripples https://reprap.org/forum/read.php?1,757017,776100#msg-776100
Quote
the_digital_dentist
One of my printers has a ball screw in the Y axis, installed to reduce the ringing I was getting when it was belt driven. It definitely improved the ringing but the noise level is so high I had to leave the machine at the makerspace because my wife complained about it. It's driven by a 425 oz-in NEMA-23 motor that has it's own DSP driver and a 32V power supply. Maximum reliable print and motion speed is limited to about 40 mm/sec with that machine because there's a nasty mechanical resonance at about 50 mm/sec that causes the Y axis to skip steps if it hits 50 mm/sec even briefly, such as when printing a circle. Otherwise I think it could print much faster. IRIC the lead of the ball screw is 10 mm/rev.

NEMA-23 motors vibrate quite a bit, even with high microstepping (64:1, IRIC), and the vibration is very efficiently coupled through the ball screw to the bed plate, hence the noise. I've tried antivibration motor mounts, etc. all to no avail. I should probably try a lower torque motor- that might push the resonance up to a higher speed...

Ok, screw that (pun not intended :) )

If we return to the timing belt concept, I´d like to report that did the following test:
- A dial gauge mounted on the printer frame so that the travelling distance in Y can be measured
- stepper motors engaged so that the motor holds the Y carriage and the axis cannot be moved by hand
- I tried rocking the heated bed forwards and backwards by hand (unfortuntely I cannot measure the force I have applied but it was not much) and I found out that there is +/- 0,25 mm elasticity in each direction.
- Next step: I held the motor shaft in place with a pair of pliers to eliminate the possibility that the the holding torque of the motor is not enough and the elasticity comes from there. Result: No change in the elasticity values (I did my best to rock the bed with the same intencity).

This means that the elasticity of the Y carriage does come from the elasticity of the timing belt. So using a wider belt (15mm) should, at least in theory, improve the ripples problem.

Maybe it is worth a try....]]> icefire General Mon, 03 Jul 2017 07:21:13 -0400 https://reprap.org/forum/read.php?1,757017,775938#msg-775938 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775938#msg-775938
Most are eaten, stop the war, stop these babies coming home in goodie bags.
]]> MechaBits General Sun, 02 Jul 2017 11:50:36 -0400 https://reprap.org/forum/read.php?1,757017,775923#msg-775923 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775923#msg-775923
Quote
icefire
All in all, I guess that printers with moving beds will always have the problem to some extent.

I have another idea: How about using a leadscrew for the Y axis instead of the GT2 belt? My heated bed is 320mm long in Y and the physical length of the axis is 420mm. In addition to that the Y carriage is pretty heavy so maybe the belt is just too elastic for this kind of weight. Maybe a leadscrew will eliminate the issue as it has no elasticity.

Any thoughts on this?

One of my printers has a ball screw in the Y axis, installed to reduce the ringing I was getting when it was belt driven. It definitely improved the ringing but the noise level is so high I had to leave the machine at the makerspace because my wife complained about it. It's driven by a 425 oz-in NEMA-23 motor that has it's own DSP driver and a 32V power supply. Maximum reliable print and motion speed is limited to about 40 mm/sec with that machine because there's a nasty mechanical resonance at about 50 mm/sec that causes the Y axis to skip steps if it hits 50 mm/sec even briefly, such as when printing a circle. Otherwise I think it could print much faster. IRIC the lead of the ball screw is 10 mm/rev.

NEMA-23 motors vibrate quite a bit, even with high microstepping (64:1, IRIC), and the vibration is very efficiently coupled through the ball screw to the bed plate, hence the noise. I've tried antivibration motor mounts, etc. all to no avail. I should probably try a lower torque motor- that might push the resonance up to a higher speed...]]> the_digital_dentist General Sun, 02 Jul 2017 10:05:13 -0400 https://reprap.org/forum/read.php?1,757017,775917#msg-775917 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775917#msg-775917 www.igus.eu]
However, I decided to replace it and go for much cheaper 10mm shafts and LM10UU linear bearings because the movement along the IGUS rail was not particularly smooth. But I still think there may be oscillation of the whole Y carriage due to the elasticity of the belt itself.. I am thinking of a way to test this theory...]]> icefire General Sun, 02 Jul 2017 09:26:41 -0400 https://reprap.org/forum/read.php?1,757017,775914#msg-775914 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775914#msg-775914 DjDemonD General Sun, 02 Jul 2017 09:18:17 -0400 https://reprap.org/forum/read.php?1,757017,775911#msg-775911 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775911#msg-775911 icefire General Sun, 02 Jul 2017 09:13:45 -0400 https://reprap.org/forum/read.php?1,757017,775910#msg-775910 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775910#msg-775910
It works for cnc as you want high thrust not high speed.]]> DjDemonD General Sun, 02 Jul 2017 09:12:19 -0400 https://reprap.org/forum/read.php?1,757017,775902#msg-775902 Re: War against ripples https://reprap.org/forum/read.php?1,757017,775902#msg-775902
I have another idea: How about using a leadscrew for the Y axis instead of the GT2 belt? My heated bed is 320mm long in Y and the physical length of the axis is 420mm. In addition to that the Y carriage is pretty heavy so maybe the belt is just too elastic for this kind of weight. Maybe a leadscrew will eliminate the issue as it has no elasticity.

Any thoughts on this?]]> icefire General Sun, 02 Jul 2017 08:51:54 -0400 https://reprap.org/forum/read.php?1,757017,759906#msg-759906 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759906#msg-759906
for driver , Stick with 4988 or go raps 128 (thb6128) or SD6128 or the tmc 26 something of the duet wifi.

finally there only 2 firmware that work well in 32 its rrf and smoothie , my opinion (rrf user) is RRF is very good and always add new stuff to firmware (for Duet board and even for radds board) and its always keep up to date, firmware are release almost every week or two with new stuff, you cant go wrong with that other than that they similar I guess. The other thing to check out is the hardware option: onboard driver/socket the number of them and stuff like that.

also beware that mks board often dont have full support from smoothie dev but I guess you can count on the mks user to help, without entering that dangerous slippery subject some statement was made about this I guess a little search around will tell you more detail about that.]]> GroupB General Sat, 01 Apr 2017 10:57:07 -0400 https://reprap.org/forum/read.php?1,757017,759901#msg-759901 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759901#msg-759901 DjDemonD General Sat, 01 Apr 2017 10:42:12 -0400 https://reprap.org/forum/read.php?1,757017,759892#msg-759892 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759892#msg-759892 A cheap alternative is mks sbase from aliexpress but... I don't know if it works well.... and it uses the controversial DRV8825..]]> icefire General Sat, 01 Apr 2017 09:21:29 -0400 https://reprap.org/forum/read.php?1,757017,759814#msg-759814 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759814#msg-759814
+ with radds you can use marlin/repetier and RRF (same as duet). So you can compare 16 bit with 32 bit using the same firmware or go RRF and see the higher quality when using a proper 32bit firmware with better segment calculation VS a modding of 8 to 32 bit firmware.]]> GroupB General Sat, 01 Apr 2017 00:24:31 -0400 https://reprap.org/forum/read.php?1,757017,759782#msg-759782 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759782#msg-759782 DjDemonD General Fri, 31 Mar 2017 17:05:03 -0400 https://reprap.org/forum/read.php?1,757017,759780#msg-759780 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759780#msg-759780 icefire General Fri, 31 Mar 2017 16:48:46 -0400 https://reprap.org/forum/read.php?1,757017,759742#msg-759742 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759742#msg-759742 DjDemonD General Fri, 31 Mar 2017 12:41:48 -0400 https://reprap.org/forum/read.php?1,757017,759737#msg-759737 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759737#msg-759737
What I know so far is that there are almost no visible ripples at 0,2mm layer height. So If I want to go lower maybe it would be a good idea to use a smaller nozzle. I guess that there is a correlation between the nozzle size, the layer height and the ripples.

I also tried switching to repetier. Apart from the fact that I needed a few hours to figure out how the auto bed leveling should be set up there is no difference in print quality.

So it would be really cool to try a 32 bit board but there is also the cost factor and, which is by far the worst, there is no guarantee that it is going to get better.]]> icefire General Fri, 31 Mar 2017 12:24:24 -0400 https://reprap.org/forum/read.php?1,757017,759632#msg-759632 Re: War against ripples https://reprap.org/forum/read.php?1,757017,759632#msg-759632 icefire experiences after upgrading to a 32-bit controller board.]]> Hatmpatn General Fri, 31 Mar 2017 05:38:19 -0400 https://reprap.org/forum/read.php?1,757017,758635#msg-758635 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758635#msg-758635 dc42 General Mon, 27 Mar 2017 02:17:20 -0400 https://reprap.org/forum/read.php?1,757017,758607#msg-758607 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758607#msg-758607
Quote
dc42

Does nebbian's machine use 0.9deg motors?

Yes.

0.9 degree motors, Ramps, Repetier, 1/16 microstepping, 160 steps/mm.

I know that 32 bit boards are faster, there's no contest there. I did the test because many people keep repeating the myth that 8 bit boards can't move a delta fast. I think that 200 mm/s is fast enough.]]> nebbian General Sun, 26 Mar 2017 18:36:13 -0400 https://reprap.org/forum/read.php?1,757017,758597#msg-758597 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758597#msg-758597
Just trying to work out now how much more of a benefit (or not) one is.]]> DjDemonD General Sun, 26 Mar 2017 17:29:02 -0400 https://reprap.org/forum/read.php?1,757017,758591#msg-758591 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758591#msg-758591 Hatmpatn General Sun, 26 Mar 2017 16:45:43 -0400 https://reprap.org/forum/read.php?1,757017,758583#msg-758583 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758583#msg-758583
I'll check the maximum movement speed when I am back at the printer. AFAIR I chose 64x because 128x didn't give me 200mm/sec Z movement.

Does nebbian's machine use 0.9deg motors?]]> dc42 General Sun, 26 Mar 2017 16:15:38 -0400 https://reprap.org/forum/read.php?1,757017,758578#msg-758578 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758578#msg-758578
That being said how fast can you get your machine moving at that microstepping rate? Its not a silly contest but if Nebbian can get his 8bit controller machine up to 200 mm/s I'm keen to see how much quicker Duetwifi actually is. Of course printing at these speeds exceeds the maximum volmetric rate of filament melt on any hotend I have but its interesting to know.]]> DjDemonD General Sun, 26 Mar 2017 16:02:06 -0400 https://reprap.org/forum/read.php?1,757017,758577#msg-758577 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758577#msg-758577
Quote
DjDemonD
Well I have got it moving at 330mm/s but I am not sure I dare to go faster this is on 1/16 to 1/256 interpolated microstepping.

I can try other modes. There's more mass now I've set up a dual flying extruder.

I currently run my delta at x64 microstepping. The steps/mm is 800.]]> dc42 General Sun, 26 Mar 2017 15:57:41 -0400 https://reprap.org/forum/read.php?1,757017,758572#msg-758572 Re: War against ripples https://reprap.org/forum/read.php?1,757017,758572#msg-758572
I can try other modes. There's more mass now I've set up a dual flying extruder.]]> DjDemonD General Sun, 26 Mar 2017 15:30:23 -0400