There have been a lot of posts about 3D printing lately, and someone suggested it might be neat to have a little guide to 3D printing, especially how it relates to pinball.
I'll start by saying I'm not an expert at 3D printing or modeling, so I'd love it if others could offer up their suggestions/ideas. I'll incorporate them into the post(s).
So, let's start with the basics.
Different 3D printing methods
First, the most popular among home machines is "Fused Deposition Modeling" (FDM for short). FDM is where a thermoplastic filament is slightly melted, extruded through a small nozzle, and deposited in layers to build up your object. Most home printers use this method. Here is an image from wikipedia that gives the general idea. Item 1 is the extruder, Item 2 is the deposited layers of plastic, and 3 is the build platform.
A second method, that is popular with the higher end machines, is "Selective Laser Sintering" (SLS). With SLS, a layer of powder is deposited on the build surface, then a laser melts specific areas together. The build surface lowers a fraction of a millimeter, and more powder is deposited. Repeat until the object is built. Here are a couple short videos that shows how SLS works:
Buying a Printer vs Using a Service (Shapeways)
Most home printers will print using plastic filament and FDM. Services like Shapeways can afford higher end printers that offer higher resolution with SLS.
For most of what I do, FDM and home printing will cover it. If I need a full color print or some very fine details like screw threads, I will order from Shapeways.
If you decide to order your own printer, I highly recommend reading the Make Guide to 3D printers.
I personally chose to go with a Printrbot Simple Metal Kit with a Heated Bed upgrade.
At first I was skeptical that one of the lowest cost printers would fill my needs, but I've come to learn that you only really sacrifice speed and maximum build size. If a 6"x6"x6" bed meets your size needs, I can't say enough about the Printrbot Simple Metal. It's a fantastic printer.
The Process of Printing an Object
The easiest way to get into 3D printing without having to model your own objects is to download pre-made models. A great source for this is Thingiverse. Pinball parts are starting to be pushed up to Thingiverse, so there is a small library starting to grow there.
For example, here is a shooter lane that swinks designed. http://www.thingiverse.com/thing:608164
You download a .STL file of the model you want to print. It contains the geometry for the object in a language your next program can understand.
Once you have the .STL file, you feed it to a slicing program. A slicing program takes a 3D model and cuts it into the layers you need to feed to the 3D printer. I use Slic3r.
Here is a quick example of how it works, you can see the model on the left, and the sliced version on the right.
Once your object has been sliced, you can generate a G-code file, which is the common language that CNC machines use.
A G-code file looks like this:
G1 X52.008 Y54.121 E2.04455
G1 X51.948 Y52.484 E2.13013
G1 X51.969 Y52.373 E2.13608
G1 X52.042 Y50.606 E2.22844
G1 X52.067 Y50.514 E2.23342
G1 X52.258 Y48.934 E2.31658
G1 X52.708 Y48.561 E2.34712
G1 X52.998 Y48.608 E2.36247
G1 X54.421 Y48.632 E2.43686
G1 X54.532 Y48.659 E2.44282
This example is a bunch of G1 commands that tell the machine to move to a specific X position, a specific Y position, and to Extrude a specific amount of filament.
Then the G-code file gets loaded into a printer control software, and slowly fed to the printer as it prints your object.
I use a Raspberry PI to control my printer, running a special image called OctoPi. It gives me a web interface to my printer. You can learn more about OctoPrint and OctoPi here: http://octoprint.org/download/
If everything worked well, you get real objects from the models:
If things don't go well, you end up with a bunch of trash plastic. It happens. I woke up from an overnight print one night with a giant spaghetti ball of filament.
Here is a pic of some of my failures when I first started.
I'm sure there are a lot more that need to be added to this, so I'll continue to edit as people post and offer suggestions.
Please post if you have any questions and I'll do my best to answer it, or find the answer for you.
Hope you are having a great new year!