3D design and printing — overview

The purpose of this post is to give a start to finish overview of the 3D design and printing process we have been using.  I’ll illustrate it with examples from one of our recent models.

  • Mathematica design:  Any program which simulates 3D images on your screen can (probably) be used to start a design, but we have primarily been using Mathematica for our designs.  It is well-suited to the models we are working on, and it is easy to export the image files.  Here is the Mathematica cheat sheet I wrote up for our first meeting.  It has some helpful hints, but different Mathematica commands will be needed depending on the sort of model you are designing.  Here is part of the Mathematica notebook used to design Jessica’s torus knot:

Screen Shot 2014-03-12 at 9.07.50 AM

 

  • Blender: After the ‘Export’ command at the end of the Mathematica notebook (like above), there will be an .stl file containing the 3D data for your model on your home directory.  In some cases, this will be sufficient to send to Makerware and print (this was the case for the design above).  But in some other cases, extra manipulation of the design will be necessary.  We have encountered two problems that need extra work.  The first is that designs in which two pieces overlap are troublesome for Makerware — it interprets the overlap as part of the ‘outside’ of the model, and thus leaves holes in the middle of our prints that should not be there.  The second problem is that surfaces produced in Mathematica using the CountourPlot3D command do not have any thickness.  Both of these problems can be solved using Blender.  I’ll address the fixes in a separate post.  For your reference, here’s the torus knot in Blender.Screen Shot 2014-03-12 at 9.21.05 AM

 

  • Makerware: After these steps, we are ready to work with our model in Makerware — the software which runs our 3D printer.  In Makerware, hit the “Add” icon, select the .stl file you are working with, and it will be imported.  The icons at the left of the screen can be used to resize and reposition your model so that we can get the best possible print. When we print the model on the printer, we will then hit “Make” (and accept the default options, which seem to be working well) and the computer by the printer will convert the data to 3D printing instructions and send them to the printer.  Before doing this, however, it is helpful to check that Makerware has done a good job of interpreting the model.  On your own computer, the “Make” menu will give you a window that allows you to “Export!” your model (rather than “Print!”).  After hitting “Export!”, save your model in the .gcode format, and move to the step below.Screen Shot 2014-03-12 at 9.30.15 AM

 

  • .gcode Check:  The .gcode file is an actual set of 3D printer instructions.  After producing them, there is a very easy way to check them online.  Go to http://gcode.ws/ and upload your .gcode file in the box at left.  After a little bit of thinking, the .gcode viewer will show you the exact moves the 3D printer will make.  The scroll bar at the bottom of the window scrolls you through the moves made in each layer; the scrollbar at the right moves you from layer to layer.  Use this to quickly step through the process of printing your model and check for any potential problems, or ways in which Makerware has misinterpreted your design. (This is how we discovered the overlap problem.)Screen Shot 2014-03-12 at 9.37.49 AM You should be able to see the support lattice that the printer will create to support your model as well as the actual printing of the model.
  • Print!:  Assuming everything looks good, the time to print is here.  Set up a time for your print run with Prof. Adeboye or Prof. Constantine.  Using your .stl file on the computer attached to the printer, repeat the Makerware steps above and choose “Print!” at the end.  Several hours later your model will be all set.  You will need to clean away the support lattice and add any paint you want.
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