Rapid Prototyping and 3D Printing

Posted March 22nd, 2013 by Bailey Jones

I just gave a talk about rapid prototyping at the Austin Hardware Startup Meetup.  We hear a lot about 3D printing these days.  Rapidly diving costs in this industry are fundamental to all the attention it is getting. Make Magazine recently came out with an edition that lists about 15 different 3D printers (all are FDM machines) at around $2000 apiece.  I’ve been using rapid prototyping since the 90s when the machinery cost closer to the top end of 100’s of thousands of dollars.  We now have many different rapid prototyping choices at a more approachable cost.  I’ve watched drastic change in this industry, and even helped design a few 3D printing machines over the years.

We have a dizzying array of acronyms to choose from when it comes to picking a rapid prototyping method (and these are just a few of the most popular):

  • SLA, Stereolithography – laser cured light sensitive resin
  • SLS, Selective Laser Sintering – laser sintered nylon powder
  • FDM, Fused Deposition Modeling – hot extruded plastic
  • RTV, Room Temp. Vucanization – Cast Urethane in silicone molds
  • Polyjet – uv cured light sensitive resin, placed with printheads
  • CNC Machining, subtractive process by computer controlled milling

If you are tinkering around by yourself, FDM is the way to go. If you have a membership to Techshop, you’ll have access to a Makerbot FDM machine and computers with CAD software (Autodesk Inventor).  This machine prints by extruding a bead of plastic though a hot nozzle.

Ideally, the prototyping method would be chosen according to the objectives of the prototype.  There’s a wide range of materials from accurate and fragile to durable and less accurate. The materials available depend on the production method.  Here’s a chart mapping out some of the characteristics of these methods.

The other side to 3D printing is to generate the 3D computer file that the machines print from. This can be a complicated task.  One option is replication, that is to scan and digitize existing objects.  More interesting to me is the creation of new things.  This requires CAD software.  There are a few inexpensive or free options available as I show in the next chart.  Have a look at the chart as a starting point for orienting yourself in this CAD landscape. 

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