Lots of Layer Shift N2+ Dual

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Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Lots of Layer Shift N2+ Dual

Postby Snalios » Thu Aug 09, 2018 1:53 pm

I've been having consistent layer shifts in all axis on my Raise3D N2+ Dual. I've already tightened all my connections. My belts are properly tensioned. The rods were recently cleaned and re-greased. The fan inside the electrical box is running strong. I've been running long ABS prints with a heated build chamber (110F). Lately I've been working with technical support to fix the issue but I figured I'd tackle this on two fronts. Yesterday at the advice of TS, I increased the X/Y jerk to 300 mm/s. Printed a test object and it came out fine. Started an 80 hour print and came in to the office to find the following shifts. Pictures of shifts attached with 300 mm/s jerk.
20180809_081410.jpg
300 mm/s Jerk Shift
20180809_081351.jpg
300 mm/s Jerk Shift
20180809_081323.jpg
300 mm/s Jerk Shift


A couple days ago i had another layer shift with my jerk settings at 12 mm/s. Pictures attached for 12 mm/s jerk.
20180808_122115.jpg
12 mm/s Jerk Shift


During all of this my default print speed was 45 mm/s, and an X/Y movement speed of 100 mm/s. I'm also using S3D.

What am I doing wrong, and what can I do to keep this from happenin? It's setting our R&D schedule back significantly, as we are relying on this printer to pump out parts that we can validate in order to move forward.

Alex M.
Posts: 189
Joined: Tue Apr 10, 2018 4:59 pm

Re: Lots of Layer Shift N2+ Dual

Postby Alex M. » Fri Aug 10, 2018 8:08 am

Have you checked the voltage of your stepper drivers? I found one of ours was low straight from the factory.
You can read more about what I did here: viewtopic.php?f=2&t=10057#p34669
And get info about checking / adjusting here: viewtopic.php?f=2&t=10057#p34788
Hope this helps!

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Lots of Layer Shift N2+ Dual

Postby Jetguy » Fri Aug 10, 2018 12:09 pm

I hope that's a typo- jerk set to 300mm/s???
That is the single worst answer I have ever seen posted in his forum. That's insane on a level words cannot really do justice if you understand what the jerk setting is and does. Seriously, tech support told you 300mm/s??
viewtopic.php?f=4&t=7551&p=30931&hilit=jerk#p29460
In general, we tell folks to reduce jerk from the factory 12mm/s to 10 or 8mm/s, and one person has experimented with 15mm/, but 300 is literally saying never apply acceleration and deceleration to any move.

Let me see if I can explain this in a simpler way.
Acceleration is also deceleration, which just means like driving in a car and starting off from stopped you accelerate slowly to the post speed limit ( that what feed rate is, a posted speed limit sign, both the desired speed and the limit) drive at the speed limit, and before another stop you brake gently and slow down (deceleration). Jerk is the setting that says the sped where you don't accelerate, you simply floor the gas and burn the tires, and then at a stop sign you slam on the brakes and hope you don't skid (skip steps) right through where you wanted to stop. Again, Jerk is a threshold value, meaning that when you set it to 300mm/s, you told the printer firmware to slam full speed instead of ramping up and lock the brakes and slide through every stop sign- no wonder it shifts all over.

That setting would never be useful as a test. Again, you told your printer the setting to basically skip steps on any print and should not be able to print that way. It doesn't help diagnose the problem, just ensures that you could not print anything.

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Lots of Layer Shift N2+ Dual

Postby Jetguy » Fri Aug 10, 2018 12:40 pm

I do understand your frustration so don't take the previous reply as my only answer, I'm just astounded that's the answer you got and tried.

Skipping steps with long print and especially tall prints- just understand that skipping a step means that some force was greater than the motor could overcome, and so a step is lost. It's that simple. Your goal is to reduce the chance that some flaw in the print curls up into the travel of the nozzle at that layer and causes a force the stepper motor cannot overcome. Yes, speed comes into play as the faster a stepper motor goes the less torque margin it has.

My advice on that specific part is that if you can, print your part laying down, not vertical. I understand why you oriented it the way you did for print quality, overhang and some other features given the shape, but I have to wonder if that part would print either laying flat with minimal support material- you'd be surprised what kind of arch you can safely print under the right conditions. and that alone would reduce your print time and increase your rate of success.

Next, dual nozzles printer- you have the risk of the second nozzle striking the print layer and the added massive weight of the stock dual extruder system. This is why many of use switch it to single and add the layer print cooling fan- something that would help with overhangs.
Given your "production" status, I really think you should look into this.

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Lots of Layer Shift N2+ Dual

Postby Jetguy » Fri Aug 10, 2018 12:49 pm

Started an 80 hour print and came in to the office to find the following shifts.


Again, right there, production, that's what I call just a bad plan. You put all your eggs in one basket. I think you might even be printing more than one part at a time? That means you wait 80 hours to fail, and then have no parts. Printing one at a time, spreading the risk of failure, you might have failures, but not 100% fail and near 4 days wasted.

If you need to print something bigger like this, again optimize your print.
Print orientation so it's shorter, less layers is faster since a layer takes time.
Print with a larger nozzle, because a larger nozzle allows taller layer height= less layers and less time per layer because the nozzle also makes a wider path for less lines it has to move to fill the same area.

You have fellow users like Johnsays and MDvolle who are also doing prints with ABS and production runs, not to mention larger nozzles.
They can give you some of the same advice, they again, do production runs in ABS and face some of the same challenges.
memberlist.php?mode=viewprofile&u=4606
memberlist.php?mode=viewprofile&u=201

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Lots of Layer Shift N2+ Dual

Postby Jetguy » Fri Aug 10, 2018 1:04 pm

Again, just the facts as I see this problem:
#1 The user is printing ABS with the printer enclosed. This increases the temp of the motors and electronics
#2 The user has a dual extruder, which means a second nozzle to hit and grab the print and cause a skipped step, let alone the moving mass of the second extruder is quite high stock.
#3 The user is printing taller parts, and that result in massive 80 hour prints, where the risk factor of any failure increases.
#4 the user is running production so the focus on reducing print time, increasing yield of good parts, and reducing risk of failure are key to success.

Removing the second extruder, switching to a lighter single extruder feeder or just at a minimum, reducing some moving mass by removing the second motor not being used would be a huge risk reduction and increase in performance.
Using a larger nozzle creates stronger parts and reduces print time by a huge factor.

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Fri Aug 10, 2018 1:12 pm

Jetguy, that is no typo. I was legitimately told to increase it to 300 mm/s. I understand what the jerk setting does, but at that time I was ready to try just about anything to get this thing to not shift. We've lost so much time from the printer having issues that my hopes of getting a Pro series have pretty much all but disappeared. It's also gotten to the point that we're having to farm out our prints to Protolabs or EMS (3D Print shops) just to get a part done.

I was a little hesitant when I was told to increase it to that value, but was told by support that they had been running an N2+ Dual with the value. My initial thought was to decrease it to 0 and then increase it incrementally until i found a good level.

I'll check my driver voltages shortly. On a side note I've printed 4 items yesterday with the 1 mm/s jerk and changed my extrusion multiplier to 0.94 per supports recommendation. All 4 items came out good but the prints were about 10mm high and only 1 hour long.

Also, they aren't really production parts so much as they are prototypes to be tested so that we can move forward in the product development. Production is not a good word to use, my apologies. I am printing with a 0.6mm nozzle btw. I've had the second nozzle removed from the hotend since the first week I got the printer (first Raise3D print failed due to collision with nozzle). We plan on upgrading to the Bondtech extruder, but in the meantime I will remove the other motor that it not being used.

The part that failed with the lower jerk setting was not set up by me, I would have given more room between parts or just did one at a time. I understand that grouping lots of parts can cause even more issues. The item that failed with the 300 mm/s jerk can only fit inside the printer standing up. I would have printed it laying down if I had the choice. The build lines would be in a more desirable direction, and the the amount of support would be drastically reduced. This is the part I'm trying to print.
Manifold Bottom.JPG

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Tue Aug 14, 2018 12:23 pm

Came in this morning to even more layer shifts. Really confused as to what is causing this.
20180814_081613.jpg
20180814_081554.jpg
20180814_081539.jpg
20180808_122115.jpg

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Tue Aug 14, 2018 12:25 pm

Last picture was a repeat. Sorry about that. Here's the picture I meant to post.
20180814_081524.jpg

Alex M.
Posts: 189
Joined: Tue Apr 10, 2018 4:59 pm

Re: Lots of Layer Shift N2+ Dual

Postby Alex M. » Tue Aug 14, 2018 7:29 pm

I replied to your post in the other thread, but based on these pictures I got one of the answers.
I would recheck your driver voltage again and if it's right at 0.9V, I would suggest lowering it and trying 0.85V or maybe even 0.8V. I have a feeling that your motors are overheating causing skipped steps.

From what I have read (and done myself) I think adjusting the drives to 0.85V should help.

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Tue Aug 14, 2018 9:29 pm

I was told that lowering would actually cause more of an issue for me. That was based off of the assumption that it's the filament runout sensor adding extra tension and that X/Y rapid movement was set to 100mm/s. when it went from one side of the print to the other it tugged on the filament and the extra tension from the sensor caused it to have a new home position. Lowering my voltage would result in a lower speed and torque.

I was told to install a full piece of PTFE tubing from the exit of the filament bay and to the top of my extruder. I was running with a small piece attached to both ends with bare filament in between. Also, was told to lower my X/Y rapid movement to 50 or 70mm/s and also change my z-hop to 0.8 since I'm printing with a 0.6mm nozzle and have 0.3mm layers.

Alex M.
Posts: 189
Joined: Tue Apr 10, 2018 4:59 pm

Re: Lots of Layer Shift N2+ Dual

Postby Alex M. » Wed Aug 15, 2018 7:16 am

That all makes sense and I know that knots in the spool can cause shifts so I can see why tugs on the spool at speed without a full PTFE tubing could too. I am sorry, in my suggestion, I assumed that you were using a full PTFE tubing, actually I assume that everyone does but I guess I am wrong.

Rereading your posts, I see that you had some shifts early on in the print. I wouldn’t expect those to be cause by motor heat but they could. However the later pictures seem to show the shift occurring only much later in the prints and on those I would assume that it was related to motor heat.

I guess the big question is “How hot do the XY motors get after 1, 2, 5, 10 hours of printing. Mine were getting “too hot to hold” after 1 hour so I decided to try and lower them. So far so good. :)

I would definitely go with a full PTFE tube and check the motor temp after some time printing. If the tubing does it, perfect! But if not and the motors are getting hot to the touch I’d give lowering the driver voltage a try. If the motors stay cool or only get warm then they are fine.

EldRick
Posts: 345
Joined: Thu Jun 22, 2017 5:55 am

Re: Lots of Layer Shift N2+ Dual

Postby EldRick » Wed Aug 15, 2018 4:20 pm

You could also route the filament around the runout sensor to see if that's the cause of the problem.

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Wed Aug 15, 2018 6:07 pm

After a few hours of printing, my motors are definitely hot. Currently running at 152F using a laser thermometer. Do you know what temp your motors were reaching?

Alex M.
Posts: 189
Joined: Tue Apr 10, 2018 4:59 pm

Re: Lots of Layer Shift N2+ Dual

Postby Alex M. » Wed Aug 15, 2018 7:09 pm

Sorry I didn't check the exact temperature of the motors. When I had my issues I did a lot of different things as one time (gantry alignment, clean & lub, and driver voltage check). When I checked the drivers I had one at 0.72V and one at 0.9V, so I first dialed them both to 0.9V but while doing a test print I felt the motors and they were HOT, too hot to hold for more than a second without the feeling of burning my hand. That's when I decided to dial them down a bit. I figured I had nothing to lose and could just dial them back up if needed.

I would check our motors now but the printer really isn't stock any more. After our 90 day electronics warranty expired, we decided to do a few upgrades including the Bondtech and the TMC2224 drivers for the X & Y motors. I think the motors are supposed to run cooler with these drivers as well as a few other pluses.

One other detail that I remembered is that Raise3D changes the motor manufacturer at some point and the new motors are more prone to heating up as I understand. Do you have the original silver motors or the new black motors? We have the new black motors.

UPDATE: We have a 3 1/2 hour print going right now. It's been a little over 1/2 hour and I just checked our motors. The warmest motor is 110F using a laser thermometer and they range from 106F - 110F.

Snalios
Posts: 17
Joined: Thu Aug 09, 2018 1:39 pm

Re: Lots of Layer Shift N2+ Dual

Postby Snalios » Thu Aug 16, 2018 12:28 pm

We'll definitely look into doing the motor and driver upgrade as our warranty for electronics is up as well. The Bondtech extruder has been on our list for some time now. But with the recent printing issues we couldn't justify upgrading anything until we got it to at least print without layer shifts.

I'm currently 23 hours into a 39 hour print. Both motors are still reading 159F, same as last night when I checked. Both voltages set to the default 0.9V. We also have the black motors. Hot to the touch but not making any weird noises and my print is coming out better (no shifts just yet).


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