auto leveling doesn't work

hello, I have some problems with the auto leveling.
everything is working fine, when i start printing the printer first goes to his home position, and after that he starts autoleveling. nothing wrong there but when it starts to print, it looks like the bed isn't level at all.
i have a kossel xl and its running marlin firmware.

sorry for my bat english, hope you guys undersand. thanks

Edited 1 time(s). Last edit at 03/10/2016 08:25AM by die.

2 questions.
Is the bed properly secured to the carriage?

Are you using 3 point or grid levelling? 3 point was
a nightmare for me. Switched to 4 point grid and it
worked literally first time.

my bed is properly secured and i use 6 point grid

A few more obvious questions.
Inductive sensor secure?
How thick is your aluminium bed?
Tried just using 4 point levelling?
What version of marlin are you running?

Im not an expert but I assume you are using an inductive sensor so it will be detecting the metal on the heater.
You seem to be printing on glass so we can ask if the glass is parallel and if the glass is siting evenly on the heater.
We can also question what response you get from the sensor if the probe is not directly over a track on the heater.
Do you autolevel when the bed is hot?

i don't use a inductive sensor , i just use a micro switch

i do autolevel when the bed is hot, i m not sure witch version of marlin i am using and if i trie using 4 point grid the print heatd touches the glass bed between probings because it is going in a bow

Urgh!
If your bed is bowed enough to visibly distort glass then i think
you might have bigger problems.
If your heatbed is warping when it is hot, either the mounting holes on the
carriage are too close or you need to back off on the mounting bolts.

Also with an inductive sensor a plain old 4mm thick piece of aluminium
is best for printing on. I had a heap of glass beds i had made up before
switching to an autolevel, then i had to bin them. If you are going to
print abs, aluminium is easy to use.

What material do you have under the heatbed?

Have a look on youtube under tom's guide. The guy has
a very good video on auto level/tramming

oke, thank you, i will switch to an alu printbed and see of the problem is still there

Friarfish,

I think you've missed the point. Die's nozzle is moving in a bowed shape between probe points. Note that he's got a delta printer.


Mine did that as well when I was trying to get autolevel to work in Marlin. The problem is that the code that moves between points is using bad motion algorithms, it just moves the carriages at a certain speed instead of trying to get the head to move in a straight line. You can either modify the code to use the proper motion call, or change the configuration to be higher before and after each probe point.


Note that I don't know of anyone who has gotten autolevel to work reliably in Marlin on a delta (myself included).

I get quite nice prints from manual calibration, however. It's not that hard once you know how.

Edited 1 time(s). Last edit at 03/16/2016 11:02PM by nebbian.

I had missed about Die having a delta.
Wouldn't have tried to help. Haven't even seen a delta
in real life.

I do wonder how he managed to get an inductive sensor to work with
a glass bed. Must have

Quote
friarfish
I had missed about Die having a delta.
Wouldn't have tried to help. Haven't even seen a delta
in real life.

I do wonder how he managed to get an inductive sensor to work with
a glass bed. Must have

His first post has a picture of a delta.
He is also using a micro switch and not an inductive sensor.

Read more before trying to lend a hand. Sorry if this is a bit harsh but you are trying to help but not even reading what hes putting down.

I don't have auto leveling active on my machine but I have ordered a sensor so for my interest:-
Is the sensor raised above the bed when moving to each X/Y position and then lower to the bed or does it move (drag across the bed to each position and then raise and lower?
What sort of switch are you using? Just wondering how it deflects if it gets dragged across the bed. My Z stop has a small wheel on a lever so if I just used that it would only role in one plane.
If its in contact with the bed is there a heat soak issue on the switch?

Im building a mini kossel and seen a video calibrating a delta is it moving like it is in 12 mins of the video youtube

---

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up and running
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Quote
nebbian
Friarfish,

I think you've missed the point. Die's nozzle is moving in a bowed shape between probe points. Note that he's got a delta printer.


Mine did that as well when I was trying to get autolevel to work in Marlin. The problem is that the code that moves between points is using bad motion algorithms, it just moves the carriages at a certain speed instead of trying to get the head to move in a straight line. You can either modify the code to use the proper motion call, or change the configuration to be higher before and after each probe point.


Note that I don't know of anyone who has gotten autolevel to work reliably in Marlin on a delta (myself included).

I get quite nice prints from manual calibration, however. It's not that hard once you know how.

if i use a 6 point grid the head does go in a straight line, only when i use 3 point grid it goes in a bow. the auto leveling is working properly i thinks but it looks like he does not use the mesurments it dit when autoleveling

Out of curiosity how big is your bed?
The biggest grid I can get on my 200*200 bed is a 2x2.
If you are able to get a 6x6 then your hotend and nozzle must be
practically next to each other or the firmware you are using mustn't
be as fussy as mine is.

Are you able to get it calibrated without auto leveling? As in you can print a layer that is pretty uniform just with manual calibration? I found myself wasting time trying to auto-level recently, the microswitch setup I had was useless as it varied from 0.01 off to 0.3 off. So I got a weird matrix transformation whenever I used it. I also found that if I didn't calibrate the delta printer perfectly, that the auto leveling didn't help much, in fact it made matters much worse.