After a good few evenings of wrangling with the latest version of Skeinforge 40 (11.02.23) I have finally got it working. Here are a few details in case others find themselves having problems too.

After upgrading, the extruder seemed not to move during a print.

The core problem boiled down to a change in how version 40 calculates feedstock throughput, the solution being to modify the e_steps_per_mm setting in the firmware (in my case from 22 to 539), and tweak the skeinforge settings.  The e_steps_per_mm calculation is micro steps per rev * gear ratio / ( pinch wheel diameter * 3.14), and in my case 3200 * (39/11) / (6.7 * 3.14) = 539.  The forum actually had a lengthy thread about this (which I annoyingly overlooked at first), but the suggestions there didn't seem to solve my problem.

After much searching, and many test attempts, I finally delved into the gcode itself.  There I found that the start gcode of the preface module had a command which set the e_steps_per_mm value back to 22! (gcode: "M92 E22") This gcode file was originally part of the Skeinforge pack that Prusa bundled as part of his introduction. I tried setting the value to E539, to match the firmware, but this seemed to send the extruder crazy, so I left it at E22 and added a command at the end to set it to E539.  The complete gcode segment is:

M140 S60 ; bed temp
M92 E22 ; custom code to set extruder steps!!
G92 X0 Y0 Z0  E0.0
G1 Z2.0 F150.0
G1 X-250.0 F2100.0
G1 X-249.0 F300.0
G1 X-251.0 F100.0
G92 X10.0
G1 Y-250.0 F2100.0
G1 Y-249.0 F300.0
G1 Y-251.0 F300.0
G92 Y0.0
G1 Y70.0 F2100.0
G1 Z-250.0 F150.0
G1 Z-249.0 F50.0
G1 Z-251.0 F50.0
G1 Y75.0 E100.0  F1000.0
G1 Y100.0 E130.0  F1000.0
G92 Z0.2
G92 E0.0
M92 E554 ; custom code to set extruder steps!!

Another gotcha was that the movement at the start of the print, to set the initial position of the print head, was very slow.  By the time the print started enough PLA had dribbled out to affect the quality.  This was caused by the "Maximum Initial Feed Rate" setting in the limit module being set to 1. I'm not sure if I set this or it was defaulted to it, but setting it to 75 sped things up.

The bright side of all this fiddling is that I now have a much better understanding of Skeinforge and gcodes, and the 20mm calibration print I fired off tonight is the best one so far!

Below are the Skeinforge settings that got the result. There is still some fine tuning to go, but perhaps they are useful for someone. I extract them to html using a groovy script at the moment, but I hope to develop something useful so people can easily record, share and compare skeinforge settings.


tonokip via prusasw bundle
Version 04.09.11
Version 11.02.23
Layer Thickness (mm): 0.4
Perimeter Width over Thickness (ratio): 1.35
Infill Solidity (ratio): 1.0
Feed Rate (mm/s): 30.0
Flow Rate Setting (float): 30.0
Object Next Layers Temperature (Celcius): 200.0

More Skeinforge Settings

Activate Bottom True
Additional Height over Layer Thickness (ratio): 0.5
Altitude (mm): 0.0
SVG Viewer: webbrowser
Add Layer Template to SVG True
Extra Decimal Places (float): 2.0
Import Coarseness (ratio): 1.0
Infill in Direction of Bridge True
Layer Thickness (mm): 0.4
Layers From (index): 0
Layers To (index): 912345678
Correct Mesh True
Unproven Mesh False
Perimeter Width over Thickness (ratio): 1.35
SVG Viewer: webbrowser
Activate Chamber: False
Bed Temperature (Celcius): 60.0
Chamber Temperature (Celcius): 30.0
Holding Force (bar): 0.0
Activate Clip True
Clip Over Perimeter Width (ratio): 0.15
Maximum Connection Distance Over Perimeter Width (ratio): 10.0
Activate Comb False
Activate Cool False
Bridge Cool (Celcius): 1.0
Orbit True
Slow Down False
Maximum Cool (Celcius): 2.0
Minimum Layer Time (seconds): 60.0
Minimum Orbital Radius (millimeters): 10.0
Name of Cool End File: cool_end.gcode
Name of Cool Start File: cool_start.gcode
Turn Fan On at Beginning True
Turn Fan Off at Ending True
Activate Dimension True
Absolute Extrusion Distance True
Relative Extrusion Distance False
Extruder Retraction Speed (mm/s): 10.0
Filament Diameter (mm): 2.8
Filament Packing Density (ratio): 0.95
Retraction Distance (millimeters): 1.0
Restart Extra Distance (millimeters): 0.0
Activate Export True
Add Export Suffix True
Do Not Delete Comments False
Delete Crafting Comments False
Delete All Comments True
Do Not Change Output True
binary_16_byte False
gcode_step False
gcode_time_segment False
gcode_small False
File Extension: gcode
Name of Replace File: replace.csv
Save Penultimate Gcode False
Activate Fill: True
Diaphragm Period (layers): 100
Diaphragm Thickness (layers): 0
Extra Shells on Alternating Solid Layer (layers): 2
Extra Shells on Base (layers): 1
Extra Shells on Sparse Layer (layers): 1
Grid Circle Separation over Perimeter Width (ratio): 0.2
Grid Extra Overlap (ratio): 0.1
Grid Junction Separation Band Height (layers): 10
Grid Junction Separation over Octogon Radius At End (ratio): 0.0
Grid Junction Separation over Octogon Radius At Middle (ratio): 0.0
Infill Begin Rotation (degrees): 45.0
Infill Begin Rotation Repeat (layers): 1
Infill Odd Layer Extra Rotation (degrees): 90.0
Grid Circular False
Grid Hexagonal False
Grid Rectangular False
Line True
Infill Perimeter Overlap (ratio): 0.15
Infill Solidity (ratio): 1.0
Infill Width over Thickness (ratio): 1.5
Solid Surface Thickness (layers): 3
Lower Left True
Nearest False
Infill > Loops > Perimeter False
Infill > Perimeter > Loops False
Loops > Infill > Perimeter False
Loops > Perimeter > Infill True
Perimeter > Infill > Loops False
Perimeter > Loops > Infill False
Activate Fillet True
Arc Point False
Arc Radius False
Arc Segment False
Bevel True
Corner Feed Rate over Operating Feed Rate (ratio): 1.0
Fillet Radius over Perimeter Width (ratio): 0.35
Reversal Slowdown Distance over Perimeter Width (ratio): 0.5
Use Intermediate Feed Rate in Corners True
Activate Home False
Name of Homing File: homing.gcode
Activate Hop False
Hop Over Layer Thickness (ratio): 1.0
Minimum Hop Angle (degrees): 30.0
Add Custom Code for Temperature Reading True
Bridge Width Multiplier (ratio): 1.0
Ascending Area True
Descending Area False
Overlap Removal Width over Perimeter Width (ratio): 0.6
Turn Extruder Heater Off at Shut Down True
Activate Interpret False
Print Interpretion False
Text Program: webbrowser
Activate Jitter True
Jitter Over Perimeter Width (ratio): 2.0
Activate Lash False
X Backlash (mm): 0.2
Y Backlash (mm): 0.3
Activate Limit True
Maximum Initial Feed Rate (mm/s): 75.0
Maximum Z Feed Rate (mm/s): 1.0
Activate Multiply: True
Center X (mm): 100.0
Center Y (mm): 100.0
Number of Columns (integer): 1
Number of Rows (integer): 1
Separation over Perimeter Width (ratio): 15.0
Activate Oozebane False
After Startup Distance (millimeters): 1.2
Early Shutdown Distance (millimeters): 1.2
Early Startup Distance Constant (millimeters): 20.0
Early Startup Maximum Distance (millimeters): 1.2
First Early Startup Distance (millimeters): 25.0
Minimum Distance for Early Startup (millimeters): 0.0
Minimum Distance for Early Shutdown (millimeters): 0.0
Slowdown Startup Steps (positive integer): 3
Execute File True
Name of End File: end.gcode
Name of Start File: startMendel05l04PLA.gcode
Set Positioning to Absolute True
Set Units to Millimeters True
Start at Home False
Turn Extruder Off at Shut Down False
Turn Extruder Off at Start Up False
Activate Raft False
Add Raft, Elevate Nozzle, Orbit: False
Base Feed Rate Multiplier (ratio): 1.0
Base Flow Rate Multiplier (ratio): 1.0
Base Infill Density (ratio): 0.5
Base Layer Thickness over Layer Thickness: 2.0
Base Layers (integer): 1
Base Nozzle Lift over Base Layer Thickness (ratio): 0.4
Initial Circling: False
Infill Overhang over Extrusion Width (ratio): 0.05
Interface Feed Rate Multiplier (ratio): 1.0
Interface Flow Rate Multiplier (ratio): 1.0
Interface Infill Density (ratio): 0.5
Interface Layer Thickness over Layer Thickness: 1.0
Interface Layers (integer): 2
Interface Nozzle Lift over Interface Layer Thickness (ratio): 0.45
Name of Support End File: support_end.gcode
Name of Support Start File: support_start.gcode
Object First Layer Feed Rate Infill Multiplier (ratio): 0.4
Object First Layer Feed Rate Perimeter Multiplier (ratio): 0.4
Object First Layer Flow Rate Infill Multiplier (ratio): 0.4
Object First Layer Flow Rate Perimeter Multiplier (ratio): 0.4
Operating Nozzle Lift over Layer Thickness (ratio): 0.5
Raft Additional Margin over Length (%): 1.0
Raft Margin (mm): 3.0
Support Cross Hatch False
Support Flow Rate over Operating Flow Rate (ratio): 1.0
Support Gap over Perimeter Extrusion Width (ratio): 1.0
None True
Empty Layers Only False
Everywhere False
Exterior Only False
Support Minimum Angle (degrees): 60.0
Activate Scale: False
XY Plane Scale (ratio): 1.01
Z Axis Scale (ratio): 1.0
SVG Viewer: webbrowser
analyze False
craft False
help False
meta False
profile True
comment False
interpret False
skeiniso False
skeinlayer True
statistic False
vectorwrite False
bottom False
carve False
chamber False
chop False
cleave False
clip False
coil False
comb False
cool False
dimension False
drill False
export False
feed False
fill False
fillet False
flow False
home False
hop False
inset False
jitter False
lash False
lift False
limit False
mill False
multiply False
oozebane False
outset False
preface False
raft False
scale False
skirt False
speed False
splodge False
stretch False
temperature True
tower False
unpause False
whittle False
widen False
wipe False
Activate Skeiniso False
Animation Line Quickening (ratio): 1.0
Animation Slide Show Rate (layers/second): 2.0
Axis Rulings True
Band Height (layers): 5
Bottom Band Brightness (ratio): 0.7
Bottom Layer Brightness (ratio): 1.0
From the Bottom False
From the Top True
Draw Arrows False
Go Around Extruder Off Travel False
Layer (index): 0
Layer Extra Span (integer): 912345678
Line (index): 0
Display Line True
View Move False
View Rotate False
Number of Fill Bottom Layers (integer): 1
Number of Fill Top Layers (integer): 1
Scale (pixels per millimeter): 15.0
Screen Horizontal Inset (pixels): 100
Screen Vertical Inset (pixels): 220
Show Gcode True
Viewpoint Latitude (degrees): 15.0
Viewpoint Longitude (degrees): 210.0
Width of Axis Negative Side (pixels): 2
Width of Axis Positive Side (pixels): 6
Width of Fill Bottom Thread (pixels): 2
Width of Fill Top Thread (pixels): 2
Width of Infill Thread (pixels): 1
Width of Loop Thread (pixels): 2
Width of Perimeter Inside Thread (pixels): 8
Width of Perimeter Outside Thread (pixels): 8
Width of Raft Thread (pixels): 1
Width of Selection Thread (pixels): 6
Width of Travel Thread (pixels): 0
Activate Skeinlayer True
Animation Line Quickening (ratio): 1.0
Animation Slide Show Rate (layers/second): 2.0
Draw Arrows True
Go Around Extruder Off Travel False
Layer (index): 0
Layer Extra Span (integer): 0
Line (index): 0
Display Line True
View Move False
Scale (pixels per millimeter): 15.0
Screen Horizontal Inset (pixels): 100
Screen Vertical Inset (pixels): 220
Show Gcode True
Show Position True
Width of Extrusion Thread (pixels): 3
Width of Selection Thread (pixels): 6
Width of Travel Thread (pixels): 1
Activate Skirt: False
Gap over Perimeter Width (ratio): 1.0
Layers To (index): 1
Activate Speed: True
Add Flow Rate: True
Bridge Feed Rate Multiplier (ratio): 1.0
Bridge Flow Rate Multiplier (ratio): 1.0
Duty Cyle at Beginning (portion): 1.0
Duty Cyle at Ending (portion): 0.0
Feed Rate (mm/s): 30.0
Flow Rate Setting (float): 30.0
Orbital Feed Rate over Operating Feed Rate (ratio): 0.5
Perimeter Feed Rate over Operating Feed Rate (ratio): 0.6
Perimeter Flow Rate over Operating Flow Rate (ratio): 0.6
Travel Feed Rate (mm/s): 30.0
Activate Splodge False
Initial Lift over Extra Thickness (ratio): 1.0
Initial Splodge Feed Rate (mm/s): 1.0
Initial Splodge Quantity Length (millimeters): 30.0
Operating Lift over Extra Thickness (ratio): 1.0
Operating Splodge Feed Rate (mm/s): 1.0
Operating Splodge Quantity Length (millimeters): 1.0
Machine Time ($/hour): 1.0
Material ($/kg): 10.0
Density (kg/m3): 930.0
Extrusion Diameter over Thickness (ratio): 1.25
Print Statistics True
Save Statistics False
Activate Stretch True
Cross Limit Distance Over Perimeter Width (ratio): 5.0
Loop Stretch Over Perimeter Width (ratio): 0.11
Path Stretch Over Perimeter Width (ratio): 0.0
Perimeter Inside Stretch Over Perimeter Width (ratio): 0.32
Perimeter Outside Stretch Over Perimeter Width (ratio): 0.1
Stretch From Distance Over Perimeter Width (ratio): 2.0
Activate Temperature: True
Cooling Rate (Celcius/second): 3.0
Heating Rate (Celcius/second): 10.0
Base Temperature (Celcius): 200.0
Interface Temperature (Celcius): 200.0
Object First Layer Infill Temperature (Celcius): 200.0
Object First Layer Perimeter Temperature (Celcius): 200.0
Object Next Layers Temperature (Celcius): 200.0
Support Layers Temperature (Celcius): 200.0
Supported Layers Temperature (Celcius): 200.0
Activate Tower False
Extruder Possible Collision Cone Angle (degrees): 60.0
Maximum Tower Height (layers): 5
Tower Start Layer (integer): 1
Activate Unpause False
Delay (milliseconds): 28.0
Maximum Speed (ratio): 1.3
Add Loops True
Add Paths True
Add Perimeters True
Layers From (index): 0
Layers To (index): 912345678
SVG Viewer: webbrowser
Activate Widen: False
Activate Wipe False
Location Arrival X (mm): -70.0
Location Arrival Y (mm): -50.0
Location Arrival Z (mm): 50.0
Location Departure X (mm): -70.0
Location Departure Y (mm): -40.0
Location Departure Z (mm): 50.0
Location Wipe X (mm): -70.0
Location Wipe Y (mm): -70.0
Location Wipe Z (mm): 50.0
Wipe Period (layers): 3