Skeinforge for RapMan

Draft

Some mission critical stuff may be missing since I am just learning. Always check the generated g-code too. - Daniel K. Schneider 11:11, 11 March 2010 (UTC) (I often just change the g-code, i.e. values of M104, M108 and Fxxx values.

Introduction

Skeinforge is a tool chain for printing 3D objects.

The purpose of this entry is to write down the most important parameters and settings for the RapMan V3.1 as installed at TECFA (each Rapman may be a different).

Otherwise, read the "official" Skeinforge article on BFB wiki. However, the BFB entries do not correspond to the organization and parameter names of the latest software version at the time of writing (11:11, 11 March 2010 (UTC)).

First steps

(1) Make sure that your printer is calibrated as it should

• Flat print bed
• You can slide about 5 sheets of paper between the print head and the print bed. If the print head (hot end) is too high, forget it ...

(2) Download the latest version

• Download: Skeinforge
• Download: Python (if needed)
• Unzip skeinforge.zip in some simple directory, e.g. c:\soft\
• Make a shortcut of the *.py file on your desktop if you like (mouse-right drag under windows)

(3) Then fix all the parameters, at least the temperatures

(4) To create g-code, click on the "Skeinforge button" (lower left) and select your .STL file

Tip: Before printing with the RapMan, heat it up with the tool setup to 248 degrees, then extrude about 50cm of filament. Then quickly, run the *.bfb (gcode) file. I found printing directly from a cold printer to be problematic...

The Interface

Skeinforge is currently in Beta and each of the three Interfaces I have seen over the last month was different :) - Daniel K. Schneider 11:11, 11 March 2010 (UTC)

Here is a screen-dump of the 2010-03-05 version:

Screen capture of Skeinforge 2010-03-05

Some parameters for Craft

• Click on the "craft" button to define parameters

Carve

• Defines characteristics of the printer. I left the defaults since they were defined for RapMan.

Parameter	Explanation	Default	My color ABS	My PLA	Comments
Layer Thickness (mm)	The thickness of the layer your printer will deposit. This defines: the thickness of layer Skeinforge will cut your object in and therefore the Z step in generated G-Code	0.4	0.4	??	I kept this, but for finer lines this might be lowered a tiny bit ?
Layers From (index)	If you don't want to print some starting layers	0	0	0	kept this
Mesh type	Correctness of the mesh	correct Mesh	-	-	kept this.
Perimeter Width over Thickness (ratio)	how thick the perimeter wall will be in relation to the layer thickness. Default value of 1.8 for default thickness of 0.4 states that single filament perimeter wall will be 0.4*1.8=0.72mm thick. This is an important calibration value. You need to be sure that speed of the head and extrusion rate in combination produce walls that are layer thickness * perimeter width over thickness thick	1.8	-	-	I kept this, but certainly should explore this a bit more ...

Chamber

Turn off, this is to control bed and chamber temperature. (Now what do they mean by "chamber") ? I know that some people have heatable print beds and working in overheated rooms ....

Clip

Clips the ends of loops to prevent bumps from forming

• Default: ON

Comb

Moves the extruder around inside holes to prevent stringers in those holes.

• Default: ON

Cool

For ABS Turn off (to be confirmed, maybe in some situations it would be needed ...)

Dimension

??

Fill

Allows to define how an object should be filled. This is an important parameter section you should adjust to your needs.

• Default: OFF (put it on for solid objects)

Parameter	Explanation	Default	My color ABS	My PLA	Comments
Solid Surface Thickness	Defines the number of solid layers that are at the bottom, top, plateaus and overhang	3	4	-
Infill Pattern:	Specifies how to fill in empty spaces inside	Grid Hexagonal	-	-	Keep this, it is so pretty

Fillet

Purpose: Rounding of corners

• Default: OFF

Flow

Can be found under "Speed" since the Feb 2010 version. The flow script sets the flow rate by writing the M108 gcode.

Jitter

Jitter jitters the loop end position to a different place on each layer to prevent the a ridge from forming.

• Default: ON

Multiply

Print several objects.

Raft

Raft is a script to create a raft, elevate the nozzle and set the temperature for the raft. In addition, there are some parameters for the rest of the object in this group (e.g. standard nozzle height). It is very important to get the raft parameters right.

• Base is the first layer and that sticks to the print bed
• Interface are the other raft layers, typically one or two.
• The temperature settings for the raft are in temperature. Also check these !

I like fat rafts and higher temperatures. That makes it stick and I still can get if off easily with a knife.

Parameter	Explanation	Default	My color ABS	My PLA	Comments
Base Feed Rate Multiplier	Speed of the print head with respect to default speed	1	1	-	Slow it down a bit or set a higher flow (below)
Base Flow Rate Multiplier	Defines the base flow rate multiplier. The greater the 'Base Flow Rate Multiplier', the thicker the base, the lower the 'Base Flow Rate Multiplier', the thinner the base.	1.0	1.0	-
Base Infill Density (ratio)	This parameter set the ratio of the base layer fill. Value of 0.1 means that only 10% of the surface will be "covered" and value of 0.9 means that 90% of the surface will be covered.	0.5	-	-	I keep that one.
Base Layer Thickness over Layer Thickness	This parameter set how much "fatter" the base layer will be compared to normal layer (most important parameter)	2	2.5	-	I like it fatter
Base Nozzle Lift over Base Layer Thickness (ratio)	Modifies the nozzle height for base layer	0.4	-	-	Kept this one. If the raft doesn't stick despite large fills and higher temps., you may lower this a tiny bit.
Interface Feed Rate Multiplier	As above for the additional raft layers	1.0	-	-
Interface Flow Rate Multiplier	As above	1.0	-	-
Interface Infill Density (ratio)	Second (and third) layers of the raft.	0.5	-	-	I also keep this
Operation Nozzle Lift over Layer Thickness (ratio).	Way to modify thickness of the "normal layers" (layers of the object). Range that makes sense is 0.4 to 0.6.	0.5	-	-	I kept this one. If you print real fine lines, than you may lower this and the other way round.

Speed

Speed is a script to set the feed rate (which means head movement speed in mm/s) and flow rate. The resulting thickness of the filament is a combination of the two plus of the temperature.

Parameter	Explanation	Default	My color ABS	My PLA	Comments
Add Flow Rate	Will add g-code	On	-	-	If nothing comes out of nozzle check this.
Feed Rate	Defines the speed of the print head	16 millimeters/second	14 (sometimes)	-	seems a bit too much for precision work.
Flow Rate	Defines the extrusion rate	210	400	-	This may be too little. I often use 350 or 400
Perimeter Feed Rate over Operating Feed Rate (ratio)	Slows the print head down when printing "outsides. Can give a higher build quality on the outside at the expense of slower build speed	1	0.8	-	Most of the time
Perimeter Flow Rate over Operating Flow Rate (ratio)	Slows down the flow rate when printer "outsides". In principle, this should match the Perimeter Feed Rate above (else lines will be too fat)	1	0.8	-	I use 0.8 most of the time
Travail feed rate	Defines the speed of the print head when it is off	16	-	-	slow down for figures with lots of little pieces, since the printer will go bang, bang, bang.

Temperature

This is mission critical. If you don't get it right:

• Raft will not stick
• Filament will not even come out or burn ....

I think that each parameter should be tuned for high quality printing. For lower quality (and that's what I do right now). I use

• About 238 for raft and support layers with ABS
• About 247 for all other with ABS

Parameter	Explanation	Default	My color ABS	My PLA	Comments
Base Temperature	Base temperature, i.e. how it starts printing the first layer of the raft	200	238	-	Default is much too low (ABS in my RapMan likes 238 for the raft...)
Interface Temperature	For the second and other layers of the raft. Should be a bit higher than base temp.	200	238	-	I also use 238 since temperature change takes time ...
Object First Layer Infill Temperature	Temp. for the fill of the first layer. Should be somewhere in between interface temperature and the following ones (so it won't glue too much)	200	247	-	I use 247 mostly, but should try 243 or something
Object First Layer Perimeter Temperature	Outside of first layer. Should be bit higher than the above	220	247	-	I use 247, but should try 245
Object Next Layers Temperature	All other layers	200	247	-	I use 247 or 248, but should try with less sometimes
Support Layers Temperature	Usually a bit lower, since adhesion is not need (nobody can see) it and it may be possible to cover greater distances if I understand right	200	247	-	I use 247 or 248, but should try with less sometimes

Links

Download

• Skeinforge

Tutorials, Manuals, etc.

• More Skeinforge (BitsFromBytes Blog).
• Skeinforge settings (BFB Blog)
• For ABS, the best information probably is ABS (BitsFromBytes Wiki)
• Skeinforge Fill
• Skeinforge Quicktip: Fill (outdated with respect to the interface)
• Skeinforge Carve