Explore 3D

3D Printing Basics

Oliver Higgins

Issue 1, July 2017

In recent times, 3D printing has taken the maker world by storm. With printers designed to replicate themselves, to the epic industrial machines, from building your child a toy, to printing houses, this new technology equates to a really exciting future for makers.

Many years ago I worked for a manufacturing company, building retail spaces such as shop fronts and food courts. My job was to design and process the routing paths for the industrial CNC (Computer Numerical Control) machines. With some clever programming we were able to push this machine quite far, producing some amazing builds that I am still proud of today. Since leaving that role, I’ve missed the opportunity to use a machine like that, which turns ideas into 3D realities. Of course, the cost involved with machines I used to work with is phenomenal; they’re worth in excess of $500,000. However, the last few years has seen an influx in the market, of maker level versions of 3D printing and milling machines, which has truly enhanced our ability to create and engineer!

Believe it or not, 3D printing has been around since the 1980s, but until recently it was a patented idea. It was only 2007 when the idea of a 3D printer for under $10,000, for rapid prototyping, was unbelievable. This period saw the birth of the RepRap printer, an open-source, self-replacing printer. By 2009 these printers were available for purchase, and ever since we’ve seen an increase in the number of different units, and lower cost options enter the market. Ten years on and in 2017 you can buy a kit for under $200!

What 3D Printing Is And Is Not

3D printing should really be termed “Rapid Prototype Development (RPD)”. If you were to view it in terms of the manufacturing world, you have a machine capable of producing any one-off design that you can construct in your head, and be able to produce in the real world. You can do this without expensive tooling or major production runs, but it comes at the cost of economies of scale and speed. Ultimately, 3D printing is slow and since there is no economy of scale, it will cost you the same amount of time and money to individually produce each unit, regardless of whether you want to produce 1 or 1000 items.

Rapid Prototyping allows us to work with a shape or small detail, and not be drawn down to trying to secure a jiffy box in the drill press, or trying to get a perfect 90° without cracking the enclosure. Instead, we can simply put a 5mm hole in the design! Take that, you 10mm x 5mm LED bar graph! Eat dirt you rectangular rocker switch!

At DIYODE, we think that the greatest thing technology has created is the opportunity to share ideas and models with people from all over the world. For example, to view some fantastic open sourced ideas and models, check out Thingiverse.

How Does 3D Printing Work?

Most modern maker-based 3D printers are FDM (Fused Deposition Modelling) style. Very simply, these units work by heating up a plastic filament and then pushing it through a small head called an “extruder”. The filament is laid down along an X-Y (left/right & back/forth) plane until everything at that level is complete. Depending on your style of printer the Z (the up/down) will then move to allow the extruder to deposit the next layer on the XY plane. This repeats and the model builds up until it is complete. Each of these can most simply be described as “slice”. The model that you created gets sliced into hundreds or even thousands of slices, and the printer deposits material on each new layer.

What Can YOU Build?

The short answer is “anything!” But the real limits are volume of the print bed, and the complexity of your design. As your designs become more complex, you will be required to build support structures to support those elements.

What Do YOU Need?

A printer, some filament (generally ABS or PLA, which are both types of plastic), CAD/3D design software, and builder software.

What Types Of Printers Exist?

There are a number of different printers available, but to focus on the FDM style of printing, the most common would be the Cartesian style printer. This is the style that the RepRap belongs to. Cartesian printers move in a X-Y-Z space, so as to move in three dimensions. The extruder sits in the X-Y axis and the Z moves via the head of lowering of the base plate.

What Is Filament?

Filament is the plastic used to print your models. It is generally sold as a roll of a single colour. It is heated to make it malleable, and then pushed through the extruder head to be laid down on your model. There are several different types of filament available but the most common is PLA and ABS, which most consumer devices use. Materials do exist, which are conductive, metal or even chocolate. Both PLA and ABS are available in filament form, and are readily available from stores like Jaycar Electronics. ABS tends to be more expensive but is considered the more durable and of superior quality among the two.

How Do YOU Use A 3D Printer?

To begin, you need a model. In simplest terms this is a 3D representation of an object. It might simply be a cube or something way more complex like a Pokémon Chess Set. For the purpose of this article, I have simply created a rectangular prism with a hole in the middle. Of course, there are large open-source libraries available on the internet, which caters to these very things. Doing an Arduino project using the standard 16 x 2 LCD? There is a box for that! Simply download the file and you’re halfway there.

But what if you need something that has not been designed yet? Most 3D Computer Aided Design (CAD) programs will allow you to design your object; however, they are often very expensive. So far the best “no cost” solution is Tinkercad. Not only is Tinkercad free, but it’s made by AutoDesk, which is one of the world’s leading CAD specialists. The tool is available for free online – you just need to register an AutoDesk account. It also has great options for kids, allowing them to have their own accounts, which you can oversee. This software is very easy to use. It offers just the basics, but allows you to create some incredibly detailed models in a short period of time. The tutorial only takes about an hour to complete, and a seven-year-old can become fluent in the process.

Once you have your model completed you need to export it to .STL or .OBJ format. We use the .STL format as it is one of the most common formats that works well with our chosen builder software.

Slic3r is an example of a software tool you need, to convert your 3D model into CNC code to drive the printer for each layer of the print. The code is called GCode, which is the generic name for a control language for CNC/3D printing machines. It is a way to tell the machine to move to various points at a desired speed, control the extrusion speed, turn fans on and off, and all sorts of other things.

To generate this code, Slic3r imports your 3D model then slices it into layers. Often you will not want to create solid pieces of plastic but, instead, create an internal rigid structure that is just as strong but much lighter. Slic3r will work all this out for you. It also provides you with various options to change how the model is created, and how your 3D printer is setup. At this point in the process, it is crucial that you know things such as the extruder diameter, the bed size, the Z height, and the size of the filament you are using. Depending on your printer you can set a Z offset for a finer calibration of your device.

Slic3r screenshot
Slic3r helps transform a 3D object into a printable article.

A NOTE ON SUPPORTS: Supports are extra material that act as “scaffolding” to hold up the parts of a design that angle over 45°. If your model has overhangs, you will need to create supports. Slic3r will construct these for you, but this is beyond the scope of this article.

Once you are happy with your setup, export to .GCODE file. These days, most printers will have an SD card or USB to transfer the file to; alternatively, please see information on your printer if it’s driven directly from the computer. The code file is text, so if you’re interested please open it up in your favourite text editor and take a look. You can see from our example below, that GCode is simply an instruction, then a point in space.

G1 X8.691 Y-36.510 E107.59018
G1 X36.510 Y-8.691 E109.36664
G1 X36.510 Y-8.252 E109.38646
G1 X8.252 Y-36.510 E111.19095
G1 X7.813 Y-36.510 E111.21076
G1 X36.510 Y-7.813 E113.04327
G1 X36.510 Y-7.375 E113.06309
G1 X7.375 Y-36.510 E114.92362
G1 X6.936 Y-36.510 E114.94344
G1 X36.510 Y-6.936 E116.83200
G1 X36.510 Y-6.497 E116.85181
G1 X6.497 Y-36.510 E118.76839

Finally, Let’s Explore The Printer!

Printing, itself, is quite straightforward but please consult the manual or setup guide for your specific brand. A few key points: zero or calibrate your printer. If you don’t know how to do this, please find out from your printer manufacturer. Most printers have a calibration process but not all of them are straightforward. We have one printer here in the DIYODE office that does not have a “calibration” function, even though it has offsets, and it is not a simple process to correct. However, using the manual override on your printer, and moving the Z axis to where it is almost touching the extruder head will get you very, very close. Once you have the Z height number from this, then you can use this offset in Slic3r. Personally, I found this to be one of the most reliable and constant ways to get a good base layer, which is important because a well-formed base will lead to a much better quality object, in the end.

Reality Versus Expectations

There seems to be a public belief, that you simply click “print” and your Pokémon will appear; kind of like the replicator in Star Trek. In reality, it would be better if you viewed the current 3D printer technology as a Rapid Prototyping device, because as we’ve mentioned, with 3D printing it takes time to create and produce a quality product.

The print time alone can be several hours or even longer than a day. Those of us here at DIYODE that have been around for some time, lament about the “jiffy box”. This wonderful piece of plastic serves to house your labour of love, as you shoehorn it into the rectangular brick that fits best! Whilst I say this as tongue-in-cheek, it is a difficult task and often does not have the form that your project needs, to truly function in the environment in which it is designed. Personally, this is what we find most exciting – the fact that we can finally produce the items we have in our head, we can dictate its function and form, and create some fantastic and unique projects.

Now, if you’ll excuse me, I have a Pokémon Chess Set to print...