[stewi]

I'm working on an extruder for my CNC machine, using the fourth axis to operate the extruder stepper.
All free software I find to convert STL file to G-code create E-axis numbers instead of A. I can modify the file output in Excel and replace E with A, but is there a way to change the letter in Mach3?
Related to this question: CNC hot wire cutter, operated with Mach3 has actually X1, Y1 and X2, Y2 axis. Can I change the letters in Mach3?

[cornbinder23]

I'm working on an extruder for my CNC machine, using the fourth axis to operate the extruder stepper.
All free software I find to convert STL file to G-code create E-axis numbers instead of A. I can modify the file output in Excel and replace E with A, but is there a way to change the letter in Mach3?
Related to this question: CNC hot wire cutter, operated with Mach3 has actually X1, Y1 and X2, Y2 axis. Can I change the letters in Mach3?

Have you tried slic3r? It outputs A axis code.
Not sure about the hotwire question though:cheers:

JTCUSTOMS

[stewi]

Thanks, slic3r looks pretty good, but is the output metric only? In this case I would need to change the settings in Mach3 to metric.

[cornbinder23]

I believe the output IS metric only, but you can keep your Mach config the same and use G21 to change the units to metric, Slic3r puts in the G21 for you.
Just remember to scale your drawings in your CAD program if you are drawing in imperial, before exporting to .stl
I have mine setup this way as I am using the same computer to run both my mill and printer (temporarily)
I also dont save the fixture when I shut mach down

JTCUSTOMS

[stewi]

Thanks, this is very helpful.
Last question: Is the extruder value the string which comes out of the nozzle or the advancement of the 3 mm filament?

; generated by Slic3r 0.8.4 on 2012-07-12 at 09:50:38

; layer_height = 0.4
; perimeters = 3
; solid_layers = 3
; fill_density = 0.4
; nozzle_diameter = 0.5
; filament_diameter = 3
; extrusion_multiplier = 1
; perimeter_speed = 30
; infill_speed = 60
; travel_speed = 130
; scale = 1
; single wall width = 0.53mm

M104 P200 ; set temperature
G28 ; home all axes
M109 P200 ; wait for temperature to be reached
G90 ; use absolute coordinates
G21 ; set units to millimeters
G0 Z0.400 F7800.000
G0 X76.420 Y94.690
G0 F1800.000 A1.00000
G1 X76.520 Y94.170 F540.000 A1.01557

[Dean448]

All feeds and distances are based on the 3mm filiment going into the extruder. So if you are feeding filiment at 30mm/min you would consume 30mm in one min. Thats how you calibrate the extruder. Slic3r calculates the actual feed of the nozzle across the part based on things like layer thickness and nozzle diameter.