3D Printing Lesson 1: Introduction to 3D Printing

Introduction to 3D printing

Before we begin, a note on this particular lesson, it's intended primarily for covering the basics generally, and getting you to think about the possibilities. As the author, I feel after a lot of this I should add: ", but this will be covered more in detail." I'm going to refrain from that by noting that this is just a very, very basic introduction, and try not to get too bogged down in details.

Let's be a little theoretical, before we get to practical:

What is 3D printing?

There's some debate over what 3D Printing is in totality. However, it boils down to basically Additive Manufacturing. So what is Additive Manufacturing? It is instead of removing material, adding it to a work piece. It's the opposite of a lot of manufacturing, which like a whittling/carving, milling, turning, almost all woodworking, even the laser cutting is all about removing material. 3D printing adds material, most commonly plastic, but it can include, resins, metals, glass, biological tissue, concrete, sugar, pastes and probably others.

Is it new?

Somewhat. It's become a lot more popular lately. Why? Because of computers. Most subtractive manufacturing can be done without computers. Sure it can speed them up and make it a lot easier, for example with CNC machines like we have including the Tormach CNC Mill/Sherline CNC Mill/Board Goblin-Circuit Board Mill, the Shopbot/V90 Routers, the Foam Cutters, and even the Laser_Cutter. All of those could be done manually moving 2 axis at a time around, and probably pretty well for most of their uses. However, the most common 3D printing method, using plastic, couldn't really be done. The reason is that 3D printing is hugely more steps than any of the subtractive methods. The machines all basically use the same thing, which is called G-code, which can be hand written. Comparing a file for making a part on a CNC mill, and one for a 3D printer, the 3D printer one is at least 1000x larger (though they aren't the same part). So 1000 more steps to do, with 3 axis to manipulate at the same time. There exist '3D printer pens' which are Additive manufacturing, but getting the output to look good, is not easy. So computer control is a prerequisite for what most people consider 3D printing.

So because 3D printers need computers, it hasn't been popular until now?

Here's where definitions get interesting, because additive manufacturing has existed, but not like 3D printers. For example: Wood filler, is adding something. Welding might be considered as well. Paint. Looked at in the strictest sense you are adding material. In some ways something with huge texture like Starry Night* might be considered one of the best 3D printing works.

Thought exercises aside, 3D printing got started with stereolithography* and resins decades ago, and added the common plastic/FDM* as well as laser sintering powders*, printing on powder with binders*. A lot of it was patented, so the entire idea could only be done or expanded by those companies. Printers of any of those types were in the hundreds of thousands of dollars range. Some still are. A lot of the current popularity and explosion of usage owes a lot to the patents expiring, the other thing is the hobby electronics like Arduinos. Arduinos, easily accessible stepper motor drivers like the pololu drivers, all contributed, to the point that you could probably make a 3D printer from the stuff now at MakeICT, including all of the electronics, and mechanical parts. The Prusa's control board was made at the old location for MakeICT, though we had to order some parts for it.

If the patents are gone, what's the limit?

This has lead to an explosion of the ideas for 3D printing, and wanting to print in metal, with some new designs and ideas going off all the time. For example for tissue replacement, using sugar to print vessels to supply nutrients to cells, meaning potentially huge things in cloned organs, as sheets of tissue were possible, but not so much structures. That was from basically a modified Mendel printer. It's exciting, because you have a lot of ideas going on, and you are getting to see something like when computers or the internet became popular, and see how people apply it to problems. There are going to be a lot of nifty but not practical ideas. There are also going to be, I think anyway, a lot more great and amazing ideas. Some people even calling it the 3rd Industrial revolution. (I don't think I agree with that, but looking at it right now, I think it has the potential to change a lot of things.) Another example of some interesting technology is this combination of a metal 3D Laser sintering printer and milling machine. There are of course combinations that someone will come up with that we haven't thought of.

Let's be practical:

[Drawing of 3D printer, with labels ** refers to a label] From here on out, generally includes all of MakeICT's printers unless otherwise specified.

How do 3D printers work?

3D printers generally basically chop the model up into layers, from bottom to top. Think if you would, using say paper, cut to a precise shape and stacked. Generally, more is required for a layer. But the basic idea is taking the model, slicing it into thin strips, then building those thin strips up. There are some things that have difficulty, the most common being where you don't have anything under a part. Most of the printers that people think of and those we have at MakeICT use melted plastic to build up the layers, and since the nozzle is small, it has to basically draw the layers, as if using a pen that draws plastic, which if the object is large, the layer can take a while.

Is 3D printing slow?

Well for the printer to build up material it has to do layers, which vary in size. Has to lay down everything within that layer, then move on to the next. Using the value of a decently high quality print at 0.1mm, every ten layers is 1mm tall. Assuming a layer may take a minute (layer time is HIGHLY variable, it varies depending on the print, so it could be a small really detailed layer, or a large one), So if you have something that's say 6cm tall, it will take an hour. Many layers take a lot longer. A simple box for Monopoly money printed on a member's printer that was about 75mm tall, and 28mm x 112.4mm.

So how do I print?

Basically, you have to have a 3D model, which is then opened by the slicer program, which slices it into layers, and then creates the g-code to go to the printer. The g-code is either put on an SD card and moved to the printer, or sent to the printer from a computer/tablet.

The process for each printer will be a bit more detailed in (for now future) lessons, for each printer: (Currently, these go to the pages on each printer, not the lessons on usage, which will be added in the future) Ultimaker 2, Reprap Mendel Prusa, Rostock Max

Why is it all metric?

Everything in 3D Printing is metric, because it's being developed internationally. Almost all development is new, so there's no established machines holding things back, as is the case with machining, in the US. If you are someone who doesn't know metric, learn to multiply your numbers by 25.4. Otherwise, you'll have prints that are less than 4% of the intended size! That's because the US inch is defined as 25.4mm. The temperatures in the printer are in degrees C. (For reference on temperature, 0C=32F, 100C=212F, and common printing temperatures of 185-260C are 365F-500F.)

Occasionally, especially in the past, you'll see a version of a part designed for imperial/english/SAE system users. That's mostly in the past, when 3D printer parts were hard to come by. If you need a metric screw/nut, etc, they are easily available online. (James L also has a lot of M3-8 stuff, and is willing to bring some to MakeICT if you ask on the forums.) Using the imperial system will either confuse you, or make you get really fast at conversion. From here on out, at most, these lessons will provide a conversion in parenthesis.

The bottom line is that the standard that all 3D printers we have, and all that the author is aware of that have been built in the past 5 years, use a mm for the unit.

Contributed questions on general 3D Printing

Feel free to add any questions here, I (or someone else) will try to answer them. Please also post to the forum, as that will likely get a swifter response. Anything here may be incorporated into the above sections.