Gcode Basics

Everything

Here is code that should be in EVERY recipe:

;now we set up for any build offsets that we may want
G21 ; use millimeters
G90 ; absolute coordinates
G0 Z5 ; lift head to avoid collisions
G28 X0 Y0 ;always home before starting a build home X and Y
G0 X0 Y0 ; move to desired origin, necessary if you want a negative offset
G92 X0 Y0 ; reset origin:to new  X and Y, it is legal to add values to x an y, I.e. X30 Y40 will
;set the current location to X30 an Y40
M83 ; relative extruder coordinates

;set up Head Flow characteristics
M6 T10 ; select all heads on yoke 1
;M227 ; enable unprime/prime on non printing moves
M221 S1.0 ; set fudge factor for extruder to 1.0
M756 S[first_layer_height] ; set first layer thickness
M757 S[nozzle_diameter] ; set layer/path width 
M729 S3  ; set 16 step mode
;set the pulses per unit volume, this is different depending on extruder type
;and material size, I.e if the 1.75mm filament is really 1.65, you can adjust this number 
;Or the Fudge factor M221 to get the correct amount of material.
M758 S0.095   ; set steps/nL

Typical S values for M758:

MK-1     ABS 1.75mm     .09-.12
EMO-25   Plasticine     .06

Layer Changes

Please also note, that if you want to take advantage of several new features regarding layer change options, ( I.E. pause at end of layer, take picture, etc) you will want to add the M790 to the layer change G-Code as well:

M790 ;announce new layer

Start Gcode

This code should be at the beginning of every Gcode file:

M757 S[nozzle_diameter] ;set layer/path width
M729 S3 ;set 16 step mode
M758 S0.095 ;set steps/nL
M734 F60 ;set error reporting interval for redundant errors to every 60 seconds
;--------------------

End Gcode

This code should be at the end of every Gcode file:

;--------------------
;M721 ;unprime
M103 ;stop extrusion
M104 T10 S0 ;turn off all extruders
M140 S0 ;turn off hotbed