Autoleveling

Ok, having gotten fed up with having to reset the MANUAL_Z_HOME_POS in Marlin everytime I do something with my print bed and struggling to level it afterward, I've decided to try autoleveling.

I know Marlin firmware supports it, but I'm not entirely sure how to go about setting it up on my printer. I have a small delta printer, so I want to keep the effector end light and would prefer a simple solution with a minimum of electronics and something that will work with my RAMPS 1.4 board.

What are the possible solutions? Do z-probes just hook to the z-min endstop? How do you prevent the probe from interfering with printing?

Thanks

Nobody uses autoleveling?

I'm using auto bed leveling in my prusa i3 with servo and end stop. but not so lucky with it I'm not getting reliable results I'm even thinking about going back to old method with paper.

I have quite many printers, and use manual leveling on all of them. It's a pain, but once it's set it shouldn't change, unless/until you change something, and then you'll have to level again. I have adjusters on my z-axis which makes if very easy to get the z-starting position set.

My opinion on auto-leveling is that it shouldn't ever be used. Here's why... If you're bed is not level to the x and y axis, and you use auto-leveling to account for it, then your prints are going to be crooked. Sure, auto-leveling will adjust the z-axis as necessary, but if your bed tilts say 1 degree in the x-axis, then your print will tilt 1 degree in the oposite direction. For short prints, it may not make a whole lot of difference, but if you're printing something tall, say a x-end, or i3 x-carriage standing on end, then that 1 degree may make a few mm offset from bottom to top, and your part will not be accurate.

Many people have various opinions on this, but this is my two cents worth.

---

Anita
3dbotshack.com

Are you saying that if my bed is at 45* toward X min my 150mm tall print of the Washington monument when set on a flat level surface in front of the printer it will lean 45* toward x max?

Edited 3 time(s). Last edit at 11/24/2014 01:26PM by zerodameaon.

@zerodameaon, Yes, because you're part will still print straight up, but the bottom would be tilted to match the bed.

---

Anita
3dbotshack.com

Huh, I have not had this issue, that would kind of defeat the purpose of auto bed leveling. I have not tried 45* but I did mess around with a good 15-20 and the whole object leaned to one side.

This guy does not have that issue either.
[www.youtube.com]

Well, I stand corrected then. That's actually very cool (the video). I wonder if the firmware I looked at before was just new, because I couldn't find anywhere in the code where it adjusted the x and y axis values to make up for the leveling. And I agree, if it didn't then it would kind of defeat the purpose of auto-leveling.

---

Anita
3dbotshack.com

Ahh, yeah might have been an earlier firmware issue, but I do agree with you, ABL does not feel worth it to me in terms of setup and calibration. It always has me worried that I am going to not be paying attention one day on a print start and the probe does not come down and everything breaks.

Ok, from the sound of it, I'd be better off designing a bed that is easier to adjust, than using autoleveling.

But the printbot guys are usiing induction proximity sensor and they are not providing any set up to adjust their bed. I was thinking about trying out induction proximity sensor. People say its reliable also even there is a tilt in x or y axis it can be adjusted by varying Z height right?

I would say perfectly flat manually leveled bed > Enhanced G29 leveled bed > Stock G29 leveled bed.

Here is how I do it on my Cartesian. [www.thingiverse.com]

@ zerodameaon :
I didn't know about that enhanced G29, I'll give it a try after changing my M5 rods in z axis, they are wobbling extremely now. I will update later

@quillford
I'm thinking about implementing that, how does that induction proximity sensor works for you? is it really that reliable than the mechanical end switch?

Quote
jhondon
@ zerodameaon :
I didn't know about that enhanced G29, I'll give it a try after changing my M5 rods in z axis, they are wobbling extremely now. I will update later

@quillford
I'm thinking about implementing that, how does that induction proximity sensor works for you? is it really that reliable than the mechanical end switch?

It works really well. I have not tried a mechanical switch, but the bottoms on my prints are perfectly flat.

Capacitive sensors are better since they can read a glass or PEI print surface directly, whereas the inductive sensor will read the alumnium heatspreader or the tracks in the PCB heater. Which makes no practical difference for many users, but if you regularly change your print surface it might be an issue.

Quote
Andrew Smith
Capacitive sensors are better since they can read a glass or PEI print surface directly, whereas the inductive sensor will read the alumnium heatspreader or the tracks in the PCB heater. Which makes no practical difference for many users, but if you regularly change your print surface it might be an issue.

Interesting. Does it work the same way in terms of configuring the firmware? I am looking to get a glass or PEI bed.

Although capacitive sensors will sense some insulators (those with high relative permittivity) they have to be closer than a conductive surface and I think they will react more to the bulk rather than the surface of the insulator.

If you have a conductor underneath the insulator then it reacts to both. I.e. it triggers closer than either on their own. So if you have glass over a heated bed it will trigger mainly from the metal on the bed but a little closer than it would if the glass was not present and a lot closer than if the PCB was not present.

It's all too analogue for me. I prefer a physical switch.

Edited 1 time(s). Last edit at 11/27/2014 10:08AM by nophead.

---

[www.hydraraptor.blogspot.com]

I was planning to put a steel sheet inbetween aluminium heatbed and glass incase i'm not getting good sensing distance with aluminium and glassplate like this guy here

[www.youtube.com]