Category Archives: 3D Technology

A DIY 3-d desktop STL machine you can play with

From: Stanley Sokolow <stanleysokolow@gmail.com>
Subject: A DIY 3-d desktop STL machine you can play with
To: escostudyclub@yahoo.com
Date: Tuesday, January 11, 2011, 12:39 PM

If you’ve seen the video presentations from Align Technology about their process for turning 3-d computer virtual models into aligners, you probably saw their elaborate 3-d stereolithography (STL) machines.   These devices have a platform which sits at the surface of a vat of light-cure plastic liquid and a laser which the computer controller scans across the liquid surface, drawing a horizontal cross-section of the object (patient’s teeth).   Then the controller lowers the platform a smidgen and draws (light-cures) the next thin layer, and so on until the plastic cast is built.   These machines cost hundreds of thousands of dollars each.  They are about the size of a very large refrigerator, or two.  Not practical for an orthodontic office’s lab.

I’ve seen a different approach for turning 3-d data into physical models.  This line of products uses something resembling an ink-jet printer, but instead of squirting ink, it squirts melted wax.   The jet is moved around on a flat area by the machine and builds up a model, layer by layer, like the light-cure STL machine.   The market is for engineering firms who want a quick physical prototype of mechanical parts, but it’s wax.  These devices cost about $3000 to $4000 each.

Today I discovered that a small company is showing, at the 2011 Consumer Electronics Show, a desktop 3-d STL machine that uses thermoplastic ABS filament (resembles the “string” for a string-trimmer weed-eater tool), heated by the drawing head, and extruded onto the platform.   This builds up the model the same way as the other machines, but what you get is a plastic model.  It can also make objects with PLA, which is a biodegradable plastic.  The box is small enough to sit easily on a desk or counter top.  You supply the computer.  It’s sold as a partially assembled kit, for $1,225 (US dollars).  I don’t know anything about the software that comes with it, but the ads say it is an “open source” product, so I assume it’s something a Do-It-Yourself (DIY) geek can deal with.   Here’s an article describing it, with a video:  http://www.gizmag.com/makerbot-thing-o-matic–the-diy-3d-printer/17516/.  They call it the “Thing-O-Matic”.

If you’ve ever wanted to experiment with turning 3-d orthodontic models into physical casts in your office, this may be a way to get started.  It’s not a turnkey product for orthodontic use, but a component of one if you are technically competent enough to take the idea and turn it into something practical.  Why would you want one?   Maybe, if you have eliminated plaster casts from your office records and you want the ability to turn quickly a 3-d virtual model into a physical model upon which you can make an appliance in-house, this might do it for you.  The companies that digitize impressions can produce the output in various data formats, often including the standard STL format.   Or maybe you are an orthodontic inventor and want to make prototypes of your designs for a new bracket or new instrument.  Or maybe you want to make jewelry or toys from designs you create on 3-d modeling software.  If you like to tinker with such things, check it out at: MakerBot Industries.

Have fun.

Stan