Makerbot Replicator Extruder Centering Solution

The past couple of weeks I have been enjoying my new Makerbot Replicator 3D printer but have noticed something that was not to my liking.  When I loaded a file to be printed on the Makerbot I would center the part and save it but it would not print in the center of the machine even though the software showed the part was in the center of the build platform.  This is really not a problem on this 3D printer as long as you do not try to make very big parts.  Other users online have tried and the parts will fail simply because they are not centered and will run off the edge of the build platform. I did not want this to happen so with this post I will show you how I solved this problem quickly and simply without a hassle.

The image above is the ReplicatorG software screen that I use to set up files to be printed on the Makerbot Replicator 3D printer. This software is the standard used to making 3D parts on any home use  3D printer. The display screen helps me rotate, mirror, scale and view the computer designed part that I wish to make.  In this view is a very small part that is used in the Gyrokite project that I am currently working on.  I used this small part for testing to get the calibration figured out on the Makerbot.   

  I did some research online to see if I could find a solution to my problem of parts not printing at the center location even though it shows that it should in the software setup.  Turns out that a lot of other guys are having the same problem. The only true piece of advise that was any help was a procedure I found to do a calibration set up for centering the printer.  I thought "Great, This will be perfect!"  I ran the software but could not get it to make the corrections I needed on the machine.  

  The procedure for making the correction needed is to click "File", then "Scripts", "Calibration" and lastly click "The Replicator Calibration.Gcode" selection.  This will set up a Gcode file in  the ReplicatorG software screen.  Press the run button and you will get a menu that says "Move the extruder carriage until it lies in the dead center of the build plate. Then press "Yes" to continue.  I moved the extruder carriage to dead center and the platform exactly the thickness of a sheet of paper from the print nozzles.  Then I pressed "Yes" to finish the procedure. After finishing this procedure I thought "Now my prints will be centered perfectly" No so.  I ran another test part and it had not done anything.  I measured the position of the print and found that it was printed 3/4 of an inch to the right of center.  Then a brainstorm hit me.  Why not just adjust the centering of the machine to 3/4 of an inch to the left.  Worth a shot I thought.  So before I ran the procedure again I aligned the print heads to the center to start and then readjusted them to be 3/4 of an inch off to the left.  Then I ran the procedure again. 

  These two photos show the before and after start of the simple part that I was testing.  The single circle is what was printed before making any changes to the printer extruder heads center location which is the incorrect location for the part.  The double circle is the correct location (dead center) after adjusting the start location by 3/4 of an inch to the left. 

  Since making this adjustment I have ran at least a half dozen more parts and all are centered perfectly on the build platform. Why the procedure for making the correction in the first place failed I have no idea.  But with that failure I found a simple solution that works.  Can't find any fault with that for sure.  So hopefully a lot of other people who own the Makerbot Replicator will read what I have  posted here and get their machine centered and printing just the way they want also.  Let the large 3D printing begin!