Nowadays you cannot imagine maker scene without 3D printing technology – it’s the most convenient tool for prototyping. Totem mechanical system also goes hand in hand with 3D printed parts, so this technology is commonly used in our production as well (check our STL library). 3D printing might appear as a complicated process, but it can be easy if you follow the basic guidelines. In this article we will go through fundamentals and share few tricks that will help you avoid common mistakes and achieve great prints.
CAD: design guidelines
Everything starts from the CAD platform. With your favorite program create a desired model and make sure the scale and dimensions are correct. It’s important to keep the tolerances in mind when designing model to avoid any problems during the further process. Here’s basic guidelines:
Press Fit: 0.00 mm – 0.05 mm: Parts require some applied force with a cold press to assemble.
Close Fit: 0.05 mm – 0.10 mm: Parts can be assembled or disassembled by hand with negligible clearance or force.
Free Fit: 0.10 mm – 0.20 mm: Parts can slide and/or rotate easily when assembled.
The exact numbers will also depend upon the printer you are using, so you may want to print out a few test pieces to try out the fit.
However, this tolerance method doesn’t always apply for features like holes and threads because of the plastic’s shrinkage. To ensure maximum precision, design the hole to be slightly undersized and use drill/tap to make hole/thread the right size.
Make sure not to make object’s walls too thin, because shrinkage may occur or the object might collapse.
Always try to design your projects to print without support because this will save you time, material and post production cost. Avoid overhangs or at least design them to be not steeper than 45 degrees.
Slicer: support material
Next step is to generate G-code from the model on your preferred Slicer program. The side of your part that has the most surface area on the same plane is usually the side you’ll want to print on. Although this can change depending on the object’s features. Keep in mind to select the position with least exposed overhangs so you could avoid supports.
Printing your projects without the need for support seems a lot more complicated than it might sound. Most printers (primarily FDM and SLA) can handle up to about 45 degrees of overhang without requiring supports, and can also create features like vertical holes or round arches with minimal drooping. If the overhangs are steeper than that, then you will have to use support material. There’s usually 2 types of support material: tree and accordion type. Tree type support provides less contact with model but easy removal, while accordion type provides better support but hard removal. Either way post process work is needed with risk of damaging the model.
Filament: properties and adhesion
Most 3D printers use plastic that have relatively low melting points because it needs to be feasibly heated and safe when hot. This is why ABS and PLA are used the most. PLA plastic provides better details but a bit worse mechanical properties than ABS. However, a low melting point means that they corrode very easily with applied friction. 3D printed parts are usually not suited for high speed and force situations, so consider picking filament according to the properties needed.
Some plastics are harder to print than others, but all of them might have the same issue with adhesion. Make sure if your printer is calibrated correctly (issue might be connected to Z-axis offset) and the heat bed is clean. If the problem still occurs, consider using one of these most commonly used solutions – glue, hairspray or blue tape.
If you are a hardcore maker, then eventually you will end up with loads of empty spools. 3D printing community already came up with bunch of different ideas on what you can do with them: make custom turntable, compartment box or just use spools to roll up cables. However it’s a big plastic waste and extra freight cost so we advice you to check this Master Spool idea and join the movement.
With that being said the opportunities to include 3D prints to your projects are limitless. Just make sure you follow these tips to reduce fails during printing. And even when that happens just note what went wrong and learn from your mistakes. Good luck!