Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
 

Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)  

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john.g9
(@john-g9)
Eminent Member

@guy-k2

Any idea what can be changed in Marlin 2.0 on a SKR 1.4 turbo? I swapped to the .9 degree steppers and now I can't get the sensor less homing to work. Worked fine with the 1.8 as you can imagine. I can't seem corresponding values in Marlin 2.0. 

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Posted : 20/02/2020 3:24 am
john.g9
(@john-g9)
Eminent Member

I actually got this working. Had to only lower the XY homing speed down. Left sensitivity to 100 and it seems to work well. Might could adjust the sensitivity down a bit but it working so far. 

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Posted : 21/02/2020 10:20 pm
CybrSage liked
dobbewan
(@dobbewan)
Trusted Member

@john-g9

Do you mind sharing what you specifically changed on your firmware with the SKR with the 0.9 motors? 
I am in the process now of converting everything 🙂

Thanks

Posted : 02/03/2020 8:26 pm
CybrSage liked
john.g9
(@john-g9)
Eminent Member

@dobbewan

Sure thing- here is a link to my firmware I ended up using with the Hermes / Hemera. You can use Notepad ++ and open the stock Marlin files as well as my config files and compare the two if needed. It's a handy tool to look over both documents. 

https://drive.google.com/file/d/1f10lCXzrdcyT3cIkfzY4XnrUIQaVxCvN/view?usp=sharing

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Posted : 03/03/2020 12:43 am
CybrSage and dobbewan liked
dobbewan
(@dobbewan)
Trusted Member

@john-g9

Omg you are the best!!!  I will take a look at this tonight since I just finished wiring 🙂

THANK YOU!!

Posted : 03/03/2020 2:41 pm
dobbewan
(@dobbewan)
Trusted Member

@john-g9

Another quick question. 

What kind of 0.9 motors are you using? I am using Moons 0.9 MS17HA2P4100 and didn't know if you had your firmware tuned for something different like the LDO motors that require more power. 

Thanks again!

 

Posted : 03/03/2020 4:03 pm
CybrSage liked
john.g9
(@john-g9)
Eminent Member

I sued these motors , were much cheaper and seem to be closer in spec to original steppers. The moons are close enough I think the Vref voltage would be the same. The motors I bought I did not see the point in going with the moons motors since the specs were so similar. I'm sure the moons are good motors but just to me not worth the 2x price. The .9a was the selling point for me from stepper online; seemed to be well withtin the spec needs. .

 

https://www.omc-stepperonline.com/nema-17-stepper-motor/nema-17-bipolar-0-9deg-36ncm-51oz-in-0-9a-5-4v-42x42x40mm-4-wires.html?mfp=16o-ship-from%5B59%5D%2C149-step-angle%5B0.9%5D%2C146-rated-current-a%5B0.31%2C0.4%2C0.64%2C0.7%2C0.8%2C0.85%2C0.9%2C0.95%2C1%5D

This post was modified 5 months ago by john.g9
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Posted : 04/03/2020 12:15 am
vintagepc
(@vintagepc)
Noble Member
Posted by: @john-g9

I sued these motors , were much cheaper and seem to be closer in spec to original steppers. The moons are close enough I think the Vref voltage would be the same. The motors I bought I did not see the point in going with the moons motors since the specs were so similar. I'm sure the moons are good motors but just to me not worth the 2x price. The .9a was the selling point for me from stepper online; seemed to be well withtin the spec needs. .

 

https://www.omc-stepperonline.com/nema-17-stepper-motor/nema-17-bipolar-0-9deg-36ncm-51oz-in-0-9a-5-4v-42x42x40mm-4-wires.html?mfp=16o-ship-from%5B59%5D%2C149-step-angle%5B0.9%5D%2C146-rated-current-a%5B0.31%2C0.4%2C0.64%2C0.7%2C0.8%2C0.85%2C0.9%2C0.95%2C1%5D

I bought those from amazon and use them with the stock firmware having only modified microsteps/mm.

Posted : 04/03/2020 12:49 am
CybrSage liked
dobbewan
(@dobbewan)
Trusted Member

@john-g9

Ok cool. I have some spare 0.9 OMC's somewhere I am going to try next since my moons X axis will not home and will not trigger stallguard at all. The moons on the Y I finally got to home, but this X is bringing back flashbacks to when I had my einsy on 0.9. I have taken the stallguard sensitivity all the way down to 5 and it still will not trigger. I am at a loss on why... 

Thanks for your help 🙂

Posted : 04/03/2020 5:47 pm
vintagepc
(@vintagepc)
Noble Member
Posted by: @dobbewan

@john-g9

Ok cool. I have some spare 0.9 OMC's somewhere I am going to try next since my moons X axis will not home and will not trigger stallguard at all. The moons on the Y I finally got to home, but this X is bringing back flashbacks to when I had my einsy on 0.9. I have taken the stallguard sensitivity all the way down to 5 and it still will not trigger. I am at a loss on why... 

Thanks for your help 🙂

I've found the 0.9s to be very senstive to belt tensions when it comes to homing. If they're too loose the squishiness of the belt slop prevents a solid hit and home detect. 

Posted : 04/03/2020 5:50 pm
chocki
(@chocki)
Prominent Member

I found the same at vintagepc especially on the Y axis, I had a JLTX Y axis mod on mine where the motor sits in the middle of the printer and this just would not work with stallguard and 0.9 deg motors due to slight elongation of the belts, even with the standard motor mount at the rear, I had to adjust the settings in firmware to get reliable homing every time, you should also look at a new motor bracket where the belt clamp under the Y carriage hits against the motor bracket as the end stop and not the left side linear bearing against the end of the frame as standard.

https://www.thingiverse.com/thing:2942590

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 05/03/2020 6:58 am
dobbewan
(@dobbewan)
Trusted Member

@vintagepc

Yea I got if figured out. I had some values off. 

I am having a terrible howling sound on the Y axis moons 0.9 motor on non printing acceleration movements. Trying to narrow it down. 

Posted : 07/03/2020 8:13 pm
guy.k2
(@guy-k2)
Noble Member

Sorry, haven't been able to be around much lately. Totally socked in with work at hospital with Covid outbreak worsening. This is not going away and it is near certain to become endemic. 

Posted : 07/03/2020 8:36 pm
chocki, sw3De, vintagepc and 1 people liked
CybrSage
(@cybrsage)
Honorable Member
Posted by: @guy-k2

Sorry, haven't been able to be around much lately. Totally socked in with work at hospital with Covid outbreak worsening. This is not going away and it is near certain to become endemic. 

Life is more important, keep helping people with theirs.

Posted : 07/03/2020 8:46 pm
chocki and vintagepc liked
Lukas Hejtmanek
(@luka-h19)
Active Member

Hi, 

recently I upgraded Z axis on prusa i3 mk3s. I switched to 0.9 stepper motors (17HM15-0904S) as discussed here. I also switched screws to ballscrews 8x2. It means that I need only 2 microsteps on Z axis. However, it does not work. It seems that Einsy does not like large motor steps, motors get stalled unless I limit feed rate like 200-300mm/min (xyz calibration fails in this case). On the other hand, it works, if I set microsteps to 8 and increase axis steps per unit from 400 to 1600.

Does anyone know why is this happening? Is there a chance to get it work with 2 microsteps?

Posted : 03/04/2020 10:01 am
adam.b47
(@adam-b47)
New Member

Sorry to bump this ancient thread, but is anyone else having better results with VFAs since installing the newest firmware with the new linear advance 2.0?

Before: https://imgur.com/a/nKNNvaS

After: https://imgur.com/a/uuEvtKS

Posted : 20/05/2020 3:22 am
Omnissiah
(@omnissiah)
Eminent Member
Posted by: @adam-b47

Sorry to bump this ancient thread, but is anyone else having better results with VFAs since installing the newest firmware with the new linear advance 2.0?

I've been using 3.8.0 with  0.9° stepper patches on a Bondtech extruder (using LA1.0) until recently and it worked reasonably well. A few days ago I rebased the patches onto 3.9.0 (LA1.5) and had horrible looking results at first.

It seems LA1.5 taxes the processor a lot more than 1.0 did, so I ended up having to reduce extruder E-steps from 32 to 16. That mitigated most of the problems. Some fine-tuning of the K-value followed, but Prusa's values are pretty much spot on for PLA and PETG, even for the Bondtech.

At this point the print results are almost as good looking as they used to, but not quite. Not sure what else I can try at this point. I don't see any difference on VLAs however.

This post was modified 3 months ago by Omnissiah
Posted : 22/05/2020 10:10 pm
vintagepc
(@vintagepc)
Noble Member

That seems to contradict the official announcement on LA 1.5, from the RC3 post here in the forums:

Keep in mind that LA1.5 is less demanding on the CPU than the LA1.0, therefore the prints might finish slightly sooner.

You're probably seeing the need to change E-steps as a result of the change in E-jerk.

Posted : 22/05/2020 10:21 pm
Omnissiah
(@omnissiah)
Eminent Member
Posted by: @vintagepc

That seems to contradict the official announcement on LA 1.5, from the RC3 post here in the forums:

Keep in mind that LA1.5 is less demanding on the CPU than the LA1.0, therefore the prints might finish slightly sooner.

You're probably seeing the need to change E-steps as a result of the change in E-jerk.

Are you sure? I've always been using 4.5 for E-jerk, even with firmware 3.8.0. But I admit, I don't fully understand how jerk works or waht exactly got changed in 3.9.0.

Posted : 22/05/2020 10:39 pm
nikolaistolstoy@gmail.com
(@nikolaistolstoy)
Eminent Member

I love your firmware and was just looking to compile again as I am on the old version but had a problem with Arudino this time.

I did a clean install but this time there is some error looking up the Einsy Rambo. I put in the correct additional board Url but it seems there is an error getting these.

Has anyone encountered this?

Posted : 09/06/2020 7:21 pm
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