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Monday, October 9, 2017

3D Printed Shield Generator

I'm still tinkering with my 3D printer and working on things for either generic or Star Wars specific terrain.  Right now, I'm trying to get a Star Wars style shield generator to work.


The shield generator is a file I found on Thingiverse.com.  It was designed by a fellow named shotbyscott and is part of his 'Large Star Wars Legion Accessory Pack'.  As with all of the other file on Thingiverse.com, it's completely free.

For those of you who don't know much about 3D printers, I thought I'd run down a couple of specs and how they work.  My printer is a Prusa i3 Mk2S.  It's a pretty good printer, capable of printing with a 50micron, or 0.05mm layer height.  The thinner the layers, the better the end model will look.  However...  the thinner the layers, the longer the end model will take to print.  I'm printing the shield generator on my printer's 'NORMAL' mode, which is a 0.2mm or 200micron layer height.  This is a nice trade off between speed and quality.

The first thing the printer does is lay down a couple of solid layers.  It does this by printing an outline and then filling in that outline with diagonal lines.  As it lays down additional layers, it keeps alternating the direction of the diagonal lines.  It's pretty slow, but totally entrancing to watch.  In the below picture, you can start to see the shield generator's footprint.  This much work has taken about 15 minutes.  Solid layers take a lot of time...


...which is why it's good that we don't need to make every layer solid.  Every 3D printer has an infill setting.  This is how much of the 'empty space' inside a model is to be filled with material.  You can't just print a shell, or the model would be very delicate and prone to breakage.  You also don't want to make the model solid, or it'll be heavier than it needs to be and will use too much material.  The trade off is to fill only part of the interior.  My 'NORMAL' setting fills 20% of the interior.  It does this by laying down a hexagonal pattern.  You can see the first couple of layers below.


Because the hexagonal layers aren't full layers, and because they're interior details, the printer goes much faster when laying them down.  The only downside is that my printer is a bit noisier when going fast.

At this point, you wait.  This model will take hours to print.  I'm not sure how long, but I'm guessing at least five or six.  I work a more or less traditional Monday through Friday, 9-5 sort of job.  I don't like to have the printer running when I'm not home and I don't like to have it running past 10pm.  I have neighbors and don't want to irritate them (or my wife).  Due to these points, Saturdays and Sundays tend to be my printing days.  It's Sunday as I type this.  I was out most of yesterday, so I've actually been waiting for half a week to hit print on this model.  There's a surprising amount of planning that goes into one of these suckers if you don't have the ability to run it overnight without aggravating people.

I'll post another picture later when the print is done.