If you’ve ever tried to 3D print a model with overhangs or undercuts, or even just complicated geometries, you may be familiar with the importance of support material. Of course, there are ways to reduce our reliance on using 3D print support structures through things like orienting your print in an optimal direction to reduce negative space, splitting your model into modules that can be printed without supports, etc. But love it or hate it, support structures are a natural part of the 3D printing journey as we all move beyond printing simple geometric shapes.
What is support material?
Support material is the portion (or portions) of a 3D print that is layered underneath sections like overhangs or undercuts so that they can be printed without falling or breaking because...well...gravity. These support areas are typically printed with a lower density than the actual build so that it can be more easily removed after the job is complete. Typically, overhangs that are around 45 degrees or more will require support materials to be printed properly. Anything less, and you may be able to get away without it.
How to print with support material
When printing with support structures, you have a couple options, which may or may not be limited to the type of 3D printer you have. For users with a single extruder head 3D printer, you’ll be limited to using the same material for your support structure as your main build structure, also known as “break away” supports. If you have a dual-head 3D printer, you can print your support structures with either your build material or with a dedicated support material.
Printing with a single material
Depending on your use case (or your printer limitations) a single material print may be your go-to printing strategy. Printing with homogenous materials has a couple of benefits. For one, the material you’re using is likely more economical than dedicated support material, so if cost-effectiveness is the goal, printing with a single material may be the way to go. The other aspect to consider is the material compatibility. Specifically with regards to adhesion, some materials just won’t stick to each other, so printing your support structures out of a material that is incompatible with your build material is likely to fail because your build will have nothing to adhere to. Printing with a single material takes the headache out of experimenting with various materials.
But printing with a single material isn’t always all sunshine and rainbows. There are some drawbacks to this method as well. In order to remove these support structures, you’ll need a manual implement to separate the support and build materials (literally “breaking away” pieces of your print). More complex geometries may require support structures that are hard to reach with tools like pliers and may increase your chances of damaging your print as you try to clean up the support material. Depending on the level of precision or accuracy you need for your print, or the quality of your desired finish, this technique might not be ideal. For cleaner finishes you may also need to sand down parts of your build and polish if needed, so there are some additional post-processing steps required here.
Printing with separate materials
This method is a great option to consider if you have a dual-head extruder 3D printer, and particularly if you have a more complicated print.
One of the major advantages of this technique is that it reduces potential damage to your finished build. Many popular support materials that makers use in their prints are dissolvable within a liquid solution. So after a print job is complete, you’ll submerge your build into the solution and allow the support material to dissolve away. A caveat to be aware of is that dissolution of support material can take upwards of a couple hours, so that definitely makes the total time to completion for a buildmuch longer.
Of course it is important to remember that printing with two materials runs the risk of material incompatibility which could negatively affect your print, so be sure to test printing with your two chosen materials and make sure they can reliably adhere to each other before starting on your build.
So what are our options in terms of dedicated support materials we can use? Here’s a list of the most common and popular materials to help you make the right decision when choosing your support material.
PVA (Polyvinyl Alcohol)
PVA is a water-soluble polymer. The great thing about using PVA as your support material is that you don’t need to use any sort of chemicals to clean up the support structures and can literally submerge your prints in plain water. This means your dissolving solution is easily accessible and a lot safer to use. It may take a few hours for the material to dissolve. The ideal build material to use PVA with would be PLA because their printing properties are similar and they’ve been proven to be compatible, but you can always experiment with other materials. The potential downside with using PVA here would be the cost - PVA is notably more expensive than typical build materials like PLA; in some cases it can be as much as double the cost per kg. And because PVA is hygroscopic, it doesn’t have a very long shelf life, so the material can degrade fairly quickly (for tips on the best ways to store your filament, check out our previous Tips & Tricks blog post on storing filament.
Ultimaker has created a special material known as Breakaway material in order to solve the time commitment issue of using PVA and the finish issues of using same material supports. Breakaway material is designed to be manually and easily removed from the build without causing damage or scarring to the finish. Additionally, Breakaway is compatible with a wide range of build materials, making it more easy and convenient to adopt. This material, while more expensive than typical build materials, is more affordable than PVA.
Finally, the last support material we want to discuss is HIPS. HIPS is generally used as support material for ABS builds, primarily because they have similar printing properties and are widely known to be compatible. Our team at Closed Loop Plastics has also tested and verified that our U-HIPS material works great as support for PLA builds!
Using HIPS as a support material, however, does require the use of a chemical solution known as d-Limonene for material dissolution. Remember to always be careful when working with chemicals by using it in a well-ventilated area and wearing proper protective equipment.
Some build materials also may potentially be damaged by the d-Limonene solution, so be sure to test how your build material reacts to d-Limonene. HIPS is another support material that is more affordable than PVA, and the great thing about it is that its material properties make it a great build material as well!
Whether you’re a novice maker or a seasoned one, chances are you’ve experienced or will experience 3D printing with support structures. They’re an essential part of FFF 3D printing because of the physical nature of layering material in the Z direction. As designers we can certainly implement design optimizations and adjust our printer settings to minimize the need for supports, but any amount of complexity in a model will likely result in the need for support structures to give your build the best chance of success. So we hope this article will help you figure out the best 3D printing technique for you.