Calibration of Nozzles for twin extrusion
This article relates to : Replicator 1 (Ply wood) twin and the 2X
Specifically : Aligning the nozzles in X and Y axis
About Twin Extruder Nozzle Alignment
When they are not you end up with prints like those pictured right, where one nozzle is printing too far to one direction in comparison to the other nozzle.
When twin extruding it is vital that both nozzles are calibrated to each other in the X (left—right) Y (front back) and Z (up—down) directions.
How to fix it
There are two ways to correct this.
1. Where the alignment is only out by a small degree use the LCD calibration option
On your LCD screen go to UTLILITIES - CALIBRATE NOZZLES
This will print a file that allows you to tell the machine how to fine tune the alignment by selecting the “most correct” print lines.
2. Where you are out a large amount (like the photo above)
A) Connect your bot to your computer with the USB cable
B) In Makerbot Desktop (almost identical in older Makerware), Select DEVICES—then click your device (ie Replicator Dual, or 2X) under the “Connected Devices” heading
C) Then under DEVICES select DEVICE PREFERENCES
D) Scroll all the way to the bottom on the device preferences screen where you will see the heading “Tool Offset Setting Um”
 = the X axis (left right)
 = the Y axis (front back)
 = the Z axis (up down) (should always be 0*
Um = microns Ie 45000 Um = 45mm. In the example photo this is telling the machine that the nozzles are 4.5mm apart, which is clearly wrong. In this case we changed it to 35000
E) Make small changes to ajust and then repeat a test print.
We use the Hibs cube, which is an excellent calibration piece.
* If you are out in the Z direction do not adjust it here !
Instead read our fact sheet on Z nozzle alignment
Bilby3D hopes you found this helpful.