Sunday, April 9, 2017

Centering on your bed

    (Original post from the 3D Printing Experience blog) 

Updating info Nov 5th 2017- updating to match latest marlin firmware and to straighten out some of my image rotating which confused some people with orientation. Also to add a few extra bits and info. 

If your printer is like mine you may have noticed that prints really aren't centered on the bed of the printer.

Now some printers have adjustable end stops so you can just turn a screw and set where the printer aligns it's self, But most don't have this. And honestly, unless it's really off, or you are going to print something right to the edges of your printers limits, it's not going to matter. But, it bothers me, so I went and learned how to center it. And it's not really all that hard to do. It took me a few days of reading and research to figure it out, and once I did I found it takes very little time to actually center it. So I wrote this so others can do it without having to spend the time figuring it all out.

Now you will need to be at least basically familiar with Marlin firmware and using Arduino or other software but it's not all that hard to figure out.

First step is to make sure your printer is all leveled and set correctly. It's best with this to use PLA, on a taped bed so you can mark it all up. you can just print what ever and take measurements from the edges if you don't want to use a marker on your bed, but this makes it so much easier.

Tape up you bed and move your print head to extremes, Mark the nozzle location as it often time will hit a carriage before it gets to the end of the printers bed

Draw Straight Lines down the edge of the bed where the nozzle actually stops

draw lines from corner to corner to create an X at the center point of the printable area.

Also if you write where your end stops are it will keep you from getting it spun around after printing and you go and take the glass (or what ever you are using) off. 

Now download the centering target file, and slice it. 
Download  --> Centering Target <--

Best use is if you can print at your highest resolution your printer can do and not use any rift or brim if possible. This will allow you to see the marks on the bed through the print. 
VERY IMPORTANT - Now make sure you right click on the target and select "center on platform" (this is with Cura, others may have a different command to make the target centered Make sure you use it) 

save the Gcode and print it out. After printed take a look at where it lands on the bed. the lines are 5mm space.  my X lands right in the corner of the 1st 5mm box, actually just inside, right at the corner. So I'm gunna just say -4.5mm for both X and Y in this case

Now that you have measurements, you can open up your Marlin firmware file and select the "Configuration.h" tab ..

Scroll down to the bottom of the "Z probe Settings" ("End Stop Setting" in older version of marlin) 

These are the spots where you will enter the measurement you got from the print.

Adding a negative number shifts the bed toward the end stop, (the print away from the end stop)  adding a positive number can't be done. Why? because that would make you buildable area out beyond your end stops, which it just can't do, cuz, you know,.. it'll hit the end stop. 

Enter your measurements you got off the print, compile and upload to the printer. you should be set now and all your prints should be close to center on the bed.

And print the target again to check and make sure you did it correctly... 

All centered!

Now you're prints will be properly centered on the bed from now on :)



  1. I have tried following your instruction and made changes but my prints dont move on the table. What might I be doing wrong

  2. Not sure, only guess is you have to set the slicer to match bed size. If you have the slicer set smaller or something it will land according to it. Make sure you upload the settings to the printer...

  3. Hi, I am also having a problem (anet a6) no matter what I set the X_MIN_POS and Y_MIN_POS to, it makes no difference. I have checked settings on the slicer software (simplify3d 4.0), and I have made sure that I have correctly uploaded the newly compiled software to the printer. I am at a loss :(

    1. You have a LCD on the Anet correct? when you home, the screen's X and Y numbers should correspond with what ever you set the min's to.. so say if you set it to like -10 offset, when you home, the screen should read X location at -10, not zero. If it's not you haven't uploaded correctly.. about the only thing I can guess without actually looking at it.

    2. Thanks for getting back to me so quickly :)
      I will try it in the morning, it is so late here and i'm so tired that I' likely to be making mistakes. Will let you know how I go. Thanks

    3. Join the facebook group "the 3D printing group" I'm there a lot and it's easier as you can post pictures and such. :)

  4. Hello again, could not sleep so had a coffee and tried a few things...
    if I set #define Y_MIN_POS -37 (Yep, it was that far off) and leave X_MIN_POS as 0, it works fine. But if I set Y_MIN_POS -37 and X_MIN_POS 2. It doesn't work. Maybe it is a firmware bug (Skynet3d). At least I have it working, it doesn't worry my that X is 2mm off :) Maybe this might help the other comenter ? Hope what I have said makes some sense :)

    1. Know nothing about Skynet, but in Marlin I'm pretty sure a positive number there gets it all canceled out as it can't go past the end stop. (positive 2 means the print area is 2mm beyond the endstop) so it may just be canceling out. If it's hitting the end stop then the print area isn't that far over.. so the center is off, or the bed is off center ..?

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