Sailfish Firmware - Calibration Issue

NOTE: You do not need to recalibrate your home offsets when installing Sailfish. However, should you decide to recalibrate your home offsets, then you need to first read this document. This issue will be fixed in the next release of Sailfish.

Owing to a bug in Sailfish version 4.0 (Thing-o-Matic) and 6.2 (Replicators), the home offset calibration scripts within ReplicatorG may produce

  • Replicators: an incorrect Y home offset value
  • Thing-o-Matics & Cupcaks: an incorrect X offset value

It is apparent that this has happened when you see identical X and Y home offset values in the Onboard Preferences.

This bug has been fixed in Sailfish 4.1 and 7.0 which will be released in November. The underlying issue relates to homing on more than one axis at the same time. In that case, the internal stepper position information is not correctly maintained for an axis that stops moving (endstop hit) while another axis is still homing. The workaround scripts below side step the issue by only homing on one axis at a time.

This bug is not serious: its impact on the operation of your printer is that prints will not be correctly centered on the Y axis for Replicators and on the X axis for Thing-o-Matics and Cupcakes.

There are several ways to work around this issue:

  • Manually change the incorrect offset using ReplicatorG's Machine > Onboard Preferences. For Thing-o-Matics and Cupcakes, increase the X home offset to around -58mm. For Replicators, decrease the Y home offset to around 75mm.
  • On Thing-o-Matics with Gen 4 LCD interfaces, run the calibration script from the LCD display.
  • For Replicators, from ReplicatorG run this revised calibration script which homes each axis independently
(*** This script will guide you through ***)
(*** calibrating the start position on  ***)
(***      your Makerbot Replicator      ***)
G21 (Use Millimeters as Units)
G90 (Absolute Positioning)
M18 (Disable stepper motors)
M70 P10 (Move carriage to    center of plate)
M01 (Move the extruder carriage until it lies in the dead center of the build plate, then press yes to continue.)
M70 P10 (Check distance      from nozzle to plate)
M01 (Check the distance between the extruder nozzles and the build plate. They should be about one business card thickness apart. )
G92 X0 Y0 Z0 A0 B0 (Declare the current position to be (0,0,0,0,0))
G161 Z F1000 (Home Z axis minimum; go until reaching the end stop.)
(G92 Z0.0 (Set Z to 0)
G162 Y F4000 (Home Y axis maximum; go until reaching the end stop.)
G162 X F4000 (Home X axis maximum; go until reaching the end stop.)
M131 X Y (record the current coordinates to the motherboard)
M70 P10 (Calibration complete)
M01 (Your coordinates are now saved! To adjust them, use the 'Machine Onboard Preferences' dialog in the Machine menu to change the Axis Offsets.)
  • For Thing-o-Matics and Cupcakes, from ReplicatorG run this revised calibration script which homes each axis independently
(***  Thing-O-Matic calibration script  ***)
(***                                    ***)
(*** This script will guide you through ***)
(*** calibrating the start position     ***)
(*** on your Thing-O-Matic.             ***)

M18 (This disables the stepper motors.)
M01 (Move the build platform until the nozzle lies in the center, then turn the threaded rod until the nozzle just touches the surface without pressing into it. Then, press yes to continue.)
G92 X0 Y0 Z0 A0 B0 (Declare the current position to be (0,0,0,0,0))
G162 Z F500 (Home Z axis maximum; go until reaching the end stop.)
G161 X F2500 (Home X axis minimum; go until reaching the end stop.)
G161 Y F2500 (Home Y axis minimum; go until reaching the end stop.)
M131 X Y Z A B (record the current coordinates to the motherboard)

M00 (Congratulations, your coordinates are now saved! To tweak them, use the 'Motherboard Onboard Preferences' dialog in the Machine menu. <br/>Note: You will need to re-generate your gcode files using a new profile in order to use these saved settings.)
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