3D Printing Basics
You probably heard about 3D printing, but do you know what it is and understand how it works? 3D printing is a form of additive manufacturing, while a lot of other manufacturing processes are subtractive, meaning they remove material from a solid piece. For example Milling, Turning or just if you drill a hole. There are lots of different 3D printing methods, but for home use the most common one is FDM (Fused Deposition Modeling) which melts plastic and creates an object layer by layer. Another 3D printing method which is becoming more and more accessible for hobby use are DLP or SLA printers. Both types use a light source (laser for SLA and a display for DLP) which then cures a resin to also create an object layer by layer. But this method is a bit more messy, smells and needs more post processing. Therefor you can create much finer details. But on this guide we are going to focus on FDM printers.
Additive manufacturing itself is not new, it has been used in industry since 1980. Just now it is getting more popular, accessible and affordable for hobby use. This is not going to be an in depth guide, this is just to give you a rough understanding about the 3D printing related terms and how the printing process works.
Let’s start with some words you should know to understand 3D printing. The plastic which melts during the process is called filament and usually has a thickness of 1,75mm (there are also 3 or 2.85mm filaments, but they are not as widely used). This filaments melts inside the extruder and the molten plastic then squeezes out of the nozzle. The print bed is part of the printer, where the model builds onto. Sometimes this bed is also heated, to help with adhesion and let the plastic cool down slower. If you create your own 3D models you use a CAD Software – a good software for getting started is fusion 360, which is free for private use. If you want to print an object you need an .STL-File which is a file-format for 3D objects. Next you open this file in your Slicer which is the software that slices the model into layers which then can be printed – a free slicer software is for example Cura. There are lots of settings you have to tweek in your slicer, but usually you can also find presets for the beginning. By exporting the file a GCode is generated. This code tells your printer how it should move and what to do.
Which Filament to use?
The most common filaments types are ABS and PLA. While PLA is very easy to print and can be printed at 190°C (374°C), it is brittle and starts to soften at ~60°C (140°F), which for some applications is not enough. ABS on the other hand prints at a higher temperature 230°C (446°F) and therefore can withstand higher temperatures and is much stronger. The downsides however are, that ABS is more difficult to print. It shrinks more and therefore warps while printing. A enclosure helps to reduce warping, but still it is more difficult to print. Furthermore ABS releaes fumes, for which reason it should be printed in a ventilated area.
But there are also alternatives to ABS. Most of my prints are made of PETG, which is also a lot stronger than PLA, slightly flexible but warps a lot less than ABS and does not realease harmful fumes.I print it at 230°C (446°F) whith a heated bet at 80°C (176°F). One downside of PETG is, that it is a bit more stringy. With some tuning in the slicer you can reduce the stringing.
Another alternative for a strong and heat resistent filament is ASA, which is a modified version of ABS which is designed to warp less. I just started using this material and so far I really like it. It still has a tendency to warp, but much less than ABS. I print it at 245°C (473°F) with the heat bed at 100°C (212°).