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:

https://www.youtube.com/watch?feature=player_embedded&v=sFpSxX0SzgY

https://www.youtube.com/watch?feature=player_embedded&v=-6ItiCbYFvI

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.

10671323_10153440084203569_301079759855727570_n (1).jpg

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

336893-i_preview_featured.jpg

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.

Figure2_Rapid_prototyping_slicing.jpg

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:

DSC01345 (Medium).JPG

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.

10689621_10153440084268569_1708276184856761357_n (1).jpg

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!

I use both. PLA is so much easier to print with than ABS. ABS parts have more "give" to them without breaking, so they seem to be more durable in mechanical assemblies.

Not sure. I have a spool of crystal clear on the way, should be here in the next couple of days. It's for testing lighting with swinks's shooter lanes. What material are ramps normally made out of? I might be able to suggest a solvent mixture that would complement a plastic repair from one of the 3D pens.

Not yet. I think my next purchase will be a scanner. There are a couple $500 range ones that I've had my eye on. For example: http://cubify.com/en/Products/Sense

Not OT at all! I agree with your vision. The example I usually give to people is the Sears parts desk. For years, you've been able to go to a Sears parts center and order a replacement part for a mower, etc... With 3D printing, I can totally see them selling the 3D version of the model for 1/4 the price of the real one, and it feeds directly to your printer. Order the part online, feed it to the printer, and have your part inside of an hour without ever leaving the house.

I use the purple elmer's glue stick on Kapton with both PLA and ABS. Completely eliminated my warping. I've also broken parts in half trying to get them unstuck, lol.

I'm jealous of your build volume. 6"x6"x6" is good for 99% of what I do, but there have been a couple opportunities where I wish I had a solid 12" in at least one axis. The printrbot seems like I could upgrade the Z to a foot or two taller and still be alright, so I may explore that.

What kind of printer do you use?

Hmmm, that's something for me to consider. Thanks for the heads up!

Those delta style printers are fascinating to watch. The math behind them must be pretty cool. Again, jealous of such a large build volume!

If time isn't an issue, I might be able to help toward the end of January.

What do you mean? Like flat clear plastics? Just want to be sure before I answer.

I love the heated bed. Granted, I've never printed without it, but there was a period where I was figuring out what bed temp works best for ABS. The bed can't reliably hold 100 degrees C, so I have it set to 90C for printing ABS, and 60C for PLA.

What methods are you using to secure your first layer down?

The thing that ended all of my warping was using Elmer's purple glue stick over the tape/kapton.

I bought big sticks from amazon: http://www.amazon.com/gp/product/B0033UTI3E/ref=oh_aui_search_detailpage

With the tape instead of kapton, you'll probably have to replace it after each print. With the kapton, I just wipe the bed off with alcohol to remove any glue residue, then run the glue stick over it again. I do it in a cross-hatch pattern.

A friend of mine swears by aqua net hairspray, but I'm not interested in the overspray going everywhere. I like the glue sticks a lot. Give it a try if you haven't already!

Cool. Message me around the end of January to remind me and we will see what I can do.

I don't use Repetier, but I can give you the info on how it works in Slic3r, I bet it's pretty similar. Slic3r does some math based on your layer height to determine the best width to extrude at.

The nozzle actually has a flat part that is wider than the hole the filament comes out of. Reference my horrible MSPaint drawing below. The red filament is coming out of the 0.4mm hole, but the head of the extruder is actually like 1.5mm wide, so it squishes it flat.

When you print the wall calibration object, you want to manually set it to extrude 0.4mm wide so you can measure the width of the single wall object to make sure its 0.4mm. That's basically testing that you are extruding the amount of filament that the computer thinks it's telling the printer to do. Another good test is the 100mm extrude test. Google it for a better description than I could ever type up.

I normally leave the thickness set to automatically be determined by Slic3r, which is what I recommend unless you have a specific need to print a certain wall thickness. Bear in mind that the number of perimeters/shells * the extrude thickness for perimeters will be your final "shell" thickness. So if you set it to extrude .4mm and have 3 perimeters, you will typically expect to have a 1.2mm thick shell.

For the parts fitting, I've seen them recommend to change the extrusion width on the external perimeters to something less than 0.4mm, but I felt that made the problem worse. What that is doing is not only changing the math for the gcode, but also forcing it to slightly under-extrude, making the outer perimeter thinner, and thus making the parts fit.

tl;dr - let it be automatic.

nozzle.jpg

Hah, totally slipped my mind that Repetier uses Slic3r. Yeah, that's the area to mess with. I've got all of mine set to 0.

Of course!

Saw a good article today that compares one of the more expensive printers against the cheap king, Printrbot Metal Simple.

http://makezine.com/2015/02/06/can-a-600-3d-printer-beat-a-20000-machine/

The comparison isn't 100% fair, because the more expensive printer would have a much easier job of printing specific objects, but it summarizes what I've found out.

There's no need to wait for a $3,000 super tech-y, scanner, laser equipped beast. The $600 printrbot simple metal is fantastic, especially for the price.

Thanks a ton bpull! I put in my order for the free insulator.