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This wiki knows about two Makerbots at AMT: Alice and Bob. Both are equipped with Plastruder MK5 extrusion heads. They process ABS plastic filament.

Alice Bob

The general workflow is to generate a STL file with some sort of 3D design software. This file is then processed by ReplicatorG, which runs the program Skeinforge on it. Skeinforge converts STL into GCode. GCode consists of the raw instructions for the hardware, and is therefore device-specific. ReplicatorG saves the spool file with type "S3G". That file is stored on an SD card, the card placed in the Makerbot, and finally Replicator3G is used to instruct the Makerbot to process the S3G file. ReplicatorG can also spool directly to the Makerbot, however this causes problems with fine structures (see below).


Approved Makerbot Operators

Since the makerbots are actually the personally owned equipment of AMT members Al (for Alice) and Mike (for Bob), there are some stipulations on usage. People wishing to use the makerbots should be approved for operation. This means that either Al or Mike has spoken to the person, shown them some of the idiosyncracies of the makerbots, and run through a supervised build with the potential operator. This allows some supervised experience in using the makerbots, which are cranky, and assures people that the makerbots will not be accidentally damaged through inexperience.

Talk to Al and Mike if you wish to be approved as a makerbot operator.

The currently approved operators are:

Helpful references:

Skeinforge Calibration Profiles

You can download David's calibration profiles directly from this link: Extract to /wherever/replicatorg-0023-mac/skein_engines/skeinforge-35/skeinforge_application/ (adjust version numbers as necessary), rename the 'prefs' directory to 'prefs.old', then rename 'davr-makerbot-profiles-xxx' to 'prefs'. Note if you do this way instead of going thru git, it's harder to collaborate with your changes. This link is provided for people who don't want to bother with git.

Tips on printing

  1. Make sure you're using Skeinforge 35 and not the old 0006 version
  2. Always keep 'Raft' enabled.
    • If you want to print with a raft:
      1. Disable 'Outline'
      2. Under 'Raft', Set "Base layers" to 1, and "Interface layers" to between 0 and 3. I personally use 2. If you do 1 or 0, it saves time...but it becomes harder to remove the raft from the object.
    • If you want to print without a raft (aka raftless)
      1. Enable 'Outline'
      2. Under 'Raft', Set "Base layers" and "Interface layers" to 0.
  3. Adjust infill density under "Fill". 0.25 is standard light objects, turn it up if you want more solid/stronger things (max 1.0). Higher = more plastic = longer to print. Also I think the "line" pattern is fine, it's faster to print than the rectangle / hexagon patterns
  4. After generating the gcode (running thru skeinforge), inspect the gcode to make sure nothing looks terribly wrong. You can do this inside Skeinforge, go to the Analyze -> Skeinlayer -> Skeinlayer buttons, then open the gcode file. You can step through the layers.

Wobble Arrestor

I bought parts to build one of these, it improves the quality of prints. Before and after image. Now we just need to finish printing the plastic parts, and actually install it.

Mechanical Endstops

These let the bot automatically return to home position. No more endless manual adjustment of the build platform and z stage to line things up just right. Still need to be installed. Connectors might need to be modified to work with the cupcake (which originally had opto endstops, which had some reliability problems)

Makerbot Specific Notes

Makerbot Alice (Alice)

Contact person: Al

Adjusted PID settings in the firmware, no longer need to set higher temperature.

Makerbot B (Bob)

Contact person: Mike G

Experiences printing fine structures

A number of test printouts were made to experiment with various settings. The printouts and the reference sheet should be stored somewhere with the bot materials.

The main problem is buildup of excess extruded material on the product for various reasons. This causes the area where the Z axis transition happens to build up higher that the current layer. The extruder head will first start smearing, the pushing material to the side (causing deformation of the product). Eventually the head will prevent the XY table from moving and cause its belts to skip.

The best thing you can do to improve a small part printout is to download the GCode onto the SD card in the makerbot. This speeds up operation of the extruder head, causing it to deposit less excess material on the product.

Some other problems with the default settings

Some other parameters that might be relevant - these have been tried but didn't improve matters significantly enough

Things We've Printed

Skeinforge Replacements

Personal tools