Height map issues

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Nxt-1
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Joined: Fri Jan 20, 2017 7:49 am

Height map issues

Post by Nxt-1 »

I am struggling to get my get my Rostock Max v3 calibrated. When I run the mesh grid compensation I get unevenness in my results which I cannot explain. As seen on the images below, there are some serious 'ridges' depending on which direction the head is traveling. A sinusoidal deviation can be seen as well.

I have checked most if not all nuts and screws I can find. I also increased belt tension to the point I thought they could snap to see If it would make a difference, it did not. Removing the PTFE-tube and the power connector from the hotend did not change anything either. And just to be clear, rotating the entire bed does not make a difference so the issue must be mechanical I presume.

Any help or info would be much appreciated.

Machine details:
- Rostock Max V3
- Stock HE280 hotend
- Duet Wifi
- UltiBot's FSR kit
- McHackneys latest design for the fsr mounting plate (made from 18 mm / 0.709 in MDF plate)

[img]http://i1132.photobucket.com/albums/m56 ... apture.png[/img]
[img]http://i1132.photobucket.com/albums/m56 ... 0sinus.png[/img]
[img]http://i1132.photobucket.com/albums/m56 ... .42.26.jpg[/img]
RichWP
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Joined: Thu Oct 20, 2016 4:17 pm

Re: Height map issues

Post by RichWP »

I have almost the exact same setup as you (only exception is that I have an E3D hotend/mount), and am getting great results. One big difference I see is that your probe area is a lot larger than mine:

Number of probe points: 137
Probe area: 314.2 cm²

Have you tried decreasing your probing radius? Mine is set to 100.
Nxt-1
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Joined: Fri Jan 20, 2017 7:49 am

Re: Height map issues

Post by Nxt-1 »

RichWP wrote:I have almost the exact same setup as you (only exception is that I have an E3D hotend/mount), and am getting great results. One big difference I see is that your probe area is a lot larger than mine:

Number of probe points: 137
Probe area: 314.2 cm²

Have you tried decreasing your probing radius? Mine is set to 100.
I will try that and attach a pic in this reply, but I do not see how this would solve anything. It seems to me you are just looking the other way instead of trying to solve a problem.

UPDATE: The ridges are still there although somewhat less, the sinusoidal shape is still there as well.

[img]http://i1132.photobucket.com/albums/m56 ... 20r100.png[/img]
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DeltaCon
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Re: Height map issues

Post by DeltaCon »

Most mechanical problems get exponentially bigger the closer the Hotend gets to the edges of the bed or the towers. It is not very uncommon to make the calibration radius smaller than bed. But still it is probably a mechanical problem. In your first picture I see some kind of rippling effect perpendicular to the Y tower. I have never seen that, but my guess is that you have issues with smooth moving of the skate on that tower. Try to move the skate in off-state (slowly!) and check if you can feel variations in smoothness. Most likely you have a bearing with unround bearing caps or one of them is not well seated (I mean the blue caps that enclose the bearings), because every full-turn of a bearing looks to be the distance between the ripples.
I am DeltaCon, I have a delta, my name is Con, I am definitely PRO delta! ;-)
Rostock V2 / E3D Volcano / FSR kit / Duet 0.6

PS.: Sorry for the avatar, that's my other hobby!
Nxt-1
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Re: Height map issues

Post by Nxt-1 »

DeltaCon wrote:Most mechanical problems get exponentially bigger the closer the Hotend gets to the edges of the bed or the towers. It is not very uncommon to make the calibration radius smaller than bed. But still it is probably a mechanical problem. In your first picture I see some kind of rippling effect perpendicular to the Y tower. I have never seen that, but my guess is that you have issues with smooth moving of the skate on that tower. Try to move the skate in off-state (slowly!) and check if you can feel variations in smoothness. Most likely you have a bearing with unround bearing caps or one of them is not well seated (I mean the blue caps that enclose the bearings), because every full-turn of a bearing looks to be the distance between the ripples.
I have checked all three towers for any noticeable roughness and could not find anything.
DeltaCon wrote:... because every full-turn of a bearing looks to be the distance between the ripples.
The distance between the ripples is exactly 15mm, the distance set for the gridspacing in the configuration. If I set the spacing to any other value the ridges move with it.
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DeltaCon
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Re: Height map issues

Post by DeltaCon »

That is a nice catch! So every next gridline is going high or low by turn. Curious...
On the Rambo board You can move the X motor connector to Y, the Y to Z, and the Z to X (don't forget to move the endstops accordingly).
After you repeat the mesh grid compensation routine, it would be interesting to know if the riples stay in the same direction, or that they rotate along with the motors.
I am DeltaCon, I have a delta, my name is Con, I am definitely PRO delta! ;-)
Rostock V2 / E3D Volcano / FSR kit / Duet 0.6

PS.: Sorry for the avatar, that's my other hobby!
Nxt-1
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Joined: Fri Jan 20, 2017 7:49 am

Re: Height map issues

Post by Nxt-1 »

DeltaCon wrote:That is a nice catch! So every next gridline is going high or low by turn. Curious...
On the Rambo board You can move the X motor connector to Y, the Y to Z, and the Z to X (don't forget to move the endstops accordingly).
After you repeat the mesh grid compensation routine, it would be interesting to know if the riples stay in the same direction, or that they rotate along with the motors.
I am using a Duet (still the same procedure) but that is smart way to change the direction of the probing. I was wondering on how to make something like that happen without the need to change the firmware. I will try that as soon as I find the time and will edit this post to report back.

UPDATE:
I rotated to motors around X->Y->Z->X. The result is still ridges, so the issue must not be related to a single tower.
[img]http://i1132.photobucket.com/albums/m56 ... 20axis.png[/img]
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