z-banding/print surface quality

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

z-banding/print surface quality

Postby Dirtsen » Wed Dec 19, 2018 10:27 pm

Hello fellow Raise3D-Users!
I am having a hard time with my Raise3D N2. I can't seem to get rid of this issue:
48377186_2553973187962698_2486149490101190656_n.jpg


at first it looked to me like z-banding. A recurring pattern that kinda matches the pitch of the leadscrew... but looking closely... I'm not so sure.

I am using a Raise3D N2 Dual with bondtech extruder upgrade
I use Simplify 3D and Cura

Material used: PLA
printed with
30mm/s outer perimeter
40mm/s inner perimeter
50mm/s infill

I own a couple of printers and had issues with z-banding before and was always able to solve the issue myself. But im at a loss here. First of all the things I tried so far:

- Rule out Filament Quality issues: I tried different brands of Filament and measured diameters. This is not the issue,
- swapped nozzles (0.4 and 0.6)
- tried each extruder
- printed with heated bed turned off or on doesn't make a difference
- printed with parts fan off or on doesn't make a difference
- PID tuned the hotend
- cleaned extruder Housing
- checked spring tension of extruder
- tried different extrusion multipliers from 0.95 to 1.0
- Checked voltages on stepper drivers (0.5v on the extruders, as should be after the bondtech upgrade)
- checked on the screws of the ballscrew-bearings. They are all loose as they should be.
- Heated bed is level.
tried different printing temperatures and speeds

Some things I noticed when i took the top black plastic housing off to get a good look:
- the belts are a not as tight as i would usually have them on my other machines
- the x and y motors have a flexible coupler. In my understanding, this could introduce problems.

My thoughts on the matter:
- I haven't ruled out z-banding entirely but I'm not sure either. The decoupled ballscrews in conjunction with the z-linear-rods should eliminate this.
- is my x or y-axis rod bent? Can it cause this kind of print surface?

I'm somewhat experienced but I'm out of my depth here. Any input on this? Something else I could try to diagnose the issue?

tulipua
Posts: 15
Joined: Mon Mar 05, 2018 12:06 pm

Re: z-banding/print surface quality

Postby tulipua » Mon Dec 24, 2018 10:55 am

Same problem...N2 Plus
No ideas...
Attachments
48390225_377318073033913_6704063273219653632_n.jpg

tulipua
Posts: 15
Joined: Mon Mar 05, 2018 12:06 pm

Re: z-banding/print surface quality

Postby tulipua » Thu Dec 27, 2018 9:27 am

Hi! Check the Z and E drivers try to change but be attentive and follow the instructions!
In my case drivers or motion board (will order new all)

zemlin
Posts: 487
Joined: Sat Oct 21, 2017 2:02 pm

Re: z-banding/print surface quality

Postby zemlin » Thu Dec 27, 2018 1:00 pm

Do you have any z-hop at retraction? That combined with the loose ball nuts *can* introduce some inconsistency on the Z height as the ball nuts can rotate freely and don't always return to the same spot when they reverse directions. You can test this by eliminating any z-hop at retraction. Then the ball screws only turn in one direction. If that resolves the issue, I have a fix.
viewtopic.php?f=5&t=9804

tulipua
Posts: 15
Joined: Mon Mar 05, 2018 12:06 pm

Re: z-banding/print surface quality

Postby tulipua » Fri Dec 28, 2018 8:30 am

I turn off retraction for a clean test

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

Re: z-banding/print surface quality

Postby Dirtsen » Fri Dec 28, 2018 12:46 pm

I don't have Z-hop enabled. That should not be an issue. I do hear a loud "clack" sound sometimes when the printer starts printing and moves the bed up or down. I can't really make out the source of the sound.
I did notice that one of my x-rods is a little bent. I ordered a replacement and will see if that fixes it. I doubt that the issue is with the Stepper drivers.
Another suspicion I have is, that the temperature of the hotend is not as stable as the thermistor "thinks"...

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

Re: z-banding/print surface quality

Postby Dirtsen » Fri Dec 28, 2018 4:46 pm

I don't know what the hell is wrong with this Forum... my replies do not show up...

Once again: I don't have Z-Hop on retractions enabled. So that should not be an issue.

Z-Axis: I can hear a loud "clack" at the beginning of the print when the bed starts to move. I've checked if the ball nuts have moved but they always stay in place.

X-Axis: During intensive inspection of the machine, I have noticed that there is a very slight bent in one of the X-rods. I have ordered a replacement and will check if the problem persists.

Extruder temp: Something I am still going to check on is how well the temperature is being kept on point. I suspect that there could be temperature drops every now and then that do not register with the machine as they should. I have a temperature sensitive material, that stays matte when printed under 200 degrees and becomes shiny when printed above that temperature. i've noticed, that I have prints with streaks of matte and shiny surface quality.

zemlin
Posts: 487
Joined: Sat Oct 21, 2017 2:02 pm

Re: z-banding/print surface quality

Postby zemlin » Fri Dec 28, 2018 9:13 pm

Dirtsen wrote:I do hear a loud "clack" sound sometimes when the printer starts printing and moves the bed up or down. I can't really make out the source of the sound.
Keep your eye on the ball nuts when the print bed starts moving. I think you'll see the ball nuts rotate a few degrees and that clack is the ball-nuts/screws/holes contacting at the end of the rotation limit.

tulipua
Posts: 15
Joined: Mon Mar 05, 2018 12:06 pm

Re: z-banding/print surface quality

Postby tulipua » Fri Dec 28, 2018 11:22 pm

I heard "clack" Z too but after lubrication motor has gone and Zemlin is right about ball nuts

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

Re: z-banding/print surface quality

Postby Dirtsen » Sun Dec 30, 2018 12:54 am

lubricating the motor? I will have a look at the ball screws... again.

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

Re: z-banding/print surface quality

Postby Dirtsen » Wed Jan 16, 2019 10:12 am

Nope, this did not fix it. the ball nuts stay in place and do not move. I am currently replacing the linear rods.

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Noren
Posts: 473
Joined: Sat Nov 26, 2016 12:54 am
Location: Borås, Sweden
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Re: z-banding/print surface quality

Postby Noren » Thu Jan 17, 2019 11:57 am

Check your motor couplers.
Skärmavbild 2019-01-17 kl. 12.56.16.png

Dirtsen
Posts: 6
Joined: Wed Dec 19, 2018 9:52 pm

Re: z-banding/print surface quality

Postby Dirtsen » Sat Jan 19, 2019 5:14 pm

Alright, I've had some time the last couple of days. I took the top of the printer and checked if the rods were straight. The Y axis rods were not... so i thought. I took them out and replaced them. When I was putting the new rods in, and getting the belts back on i noticed that the rods would bend when some pressure was put on the X-axis belts. The belt tension was okay but that got me thinking... the Y axis rods have a long standoff part before the pulleys. Long story short: I designed a small part that would help move the pulleys closer to the bearing, releasing some of the strain the rods were under. And now the problem is contained. This seems like a designflaw to me or am I wrong here? Anyways, my "banding" which turned out was a wobbling Y axis rod is now okay.

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Noren
Posts: 473
Joined: Sat Nov 26, 2016 12:54 am
Location: Borås, Sweden
Contact:

Re: z-banding/print surface quality

Postby Noren » Sun Jan 20, 2019 3:55 pm

Please share some images of your mod. Interesting.

joosty1
Posts: 1
Joined: Tue Jun 04, 2019 4:21 pm

Re: z-banding/print surface quality

Postby joosty1 » Tue Jun 04, 2019 4:30 pm

Dirtsen wrote:Long story short: I designed a small part that would help move the pulleys closer to the bearing, releasing some of the strain the rods were under. And now the problem is contained. This seems like a designflaw to me or am I wrong here? Anyways, my "banding" which turned out was a wobbling Y axis rod is now okay.



I'm very interested in hearing more about your cool fix. Could you share a file for that or maybe a picture? It sounds like a great upgrade.

I've got at least one bent rod, and Raise3D is taking weeks to get back to me about letting me order new ones. Maybe your mod can hold me over until they can get back to me with a price or specs on the rods.

loddie
Posts: 8
Joined: Wed Jun 22, 2016 3:19 pm

Re: z-banding/print surface quality

Postby loddie » Fri Feb 28, 2020 5:57 pm

I'm also interested. My rods are bent and it would be great to see photos of the mod or part files.

loddie
Posts: 8
Joined: Wed Jun 22, 2016 3:19 pm

Re: z-banding/print surface quality

Postby loddie » Wed Mar 11, 2020 6:57 pm

In case anyone would like to upgrade/replace their N2/N2+ axis rods, Raise3D provided the following dimensions:

-Z Shaft: 12mm x 752mm
-Front Shaft: 8mm x 442mm
-Right Shaft: 8mm x 451mm
-Rear Shaft: 8mm x 460mm
-Left Shaft: 8mm x 469
-Cross Shaft (x2): 8mm x 411mm (x2)


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