====Chat messages from George Burnell's 4/1/2020 presentation on 3-D Printing====
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11:09:16	 From Robert Melanson : Can that machine make a crown?
11:09:53	 From John Brown : Dr Puschak made a permanent crown for me using one of these machines while I waited in the dental chair recently.
11:10:52	 From Jerry Slate : Peter, what is your crown made of?
11:14:39	 From Steve Isenberg : Jerry, I don’t think Peter knows what the crown is made of.
11:20:01	 From Richard : What size tolerances are achievable via 3D printing - particularly compared to other processes?
11:20:51	 From Barbara Coughlin : +/- 0.05 mm
11:21:41	 From Richard : So 50 nm?
11:23:19	 From Barbara Coughlin : I don’t really know - it was just a quick google search
11:24:38	 From Charles H Holbrow : .05 mm is 50 microns not 50 nm
11:25:02	 From Jerry Slate : 0.05 mm = 50 micrometers = 50,000 nanometers
11:27:18	 From judymike : It depends on what  you're manufacturing.  For a large part, you wouldn't need 50 micron tolerance.  In the semiconductor device industry, tolerances in the nanometer range are typically required.
11:27:55	 From Carl Lazarus :  Does anyone know the status of a 3D printed steel pedestrian bridge that was supposed to be installed over a canal in Amsterdam?
11:28:10	 From Mitchell I. Wolfe : Italian hospitals were running low on valves for ventilators and the supply was not available. A university scanned one of the valves of them and 3D printed 100 of them which were started to be deployed. The cost was around $1 a piece. The manufacturer sued for patent infringement since they charge ~10K$ a piece...
11:39:42	 From Steve Isenberg : The wiki:  http://LCTG.toku.us
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