As 3D printing technology advances, we're seeing an increase in the number of final models being produced directly from 3D printers, not just prototypes, which also opens up new possibilities for designers.
This is partly due to improvements in 3D printer quality. But it's also because some interesting techniques are starting to be applied in the product design process, helping to improve the ability to print complex shapes and rigid models.
I designed an example to demonstrate the best techniques I use every day to create complex models that are as good as manufactured parts.
The design work for this model was done in SolidWorks, but the techniques used can be adapted to any design software.
The light fixture with all 3D printed parts.
This decorative pulley light fixture I designed showcases various techniques I use to create objects with difficult-to-print shapes, and enhances the joy of displaying it in my living room.
In this blog, I will introduce each part and show you where I made enhancements, where I created custom supports for difficult-to-print areas, and the Ultimaker features I used to achieve the standards I was looking for. So, let's get started.
Making the Model Stronger
The body of the light fixture is an area that can be subjected to considerable stress, and everything depends on what is suspended from the pulley. This part will have to bear the weight of the pulley, the bulb, and any lampshade you wish to add.
During the design phase, I added two 4.5mm holes to the main support.
These holes allow me to slide two 4mm threaded rods into them. Before sliding them in, I applied some super glue to the treads to hold the threaded rods in place. This will increase the weight the support can withstand while keeping the threaded rods hidden inside the model.
Apply glue before sliding in the threaded rods.
Changing Your Infill Density
You can also increase the strength of certain parts of your model by increasing the infill density in Cura. For the main body, I increased the infill pattern to 40%. This means the internal body has 40% plastic and 60% air. The rest of the parts were reduced to 20% as they are not under much stress.
However, increasing the infill density does have two main drawbacks. It increases your print time and material usage, so it's important to find an infill density that works best for your object.
40% infill 20% infill
Orientation
The bifurcated part of the wheel can be printed in two orientations: Option A or Option B, as shown in the figures below.
I chose Option B because it allows the layers to run along the U-shape, following the length of the shape instead of going across it.
The reason is that I knew that to install this wheel, I would have to pull the bifurcated parts apart to insert the axle. If I had chosen to print Option A, where the layers run along the area that needs to bend, it might snap due to fragile areas between layers.
When designing, consider the orientation of your printed object. Thinking about this early can prevent problems later.
Option A Option B
Adding the axle to the bifurcated part.
Material Selection
Material selection can also be an important factor when designing robust models. Each material has its own properties that can greatly benefit your project.
Since this is a broad topic, let's now look at the four most commonly used materials: PLA, ABS, Nylon, and CPE.
Ultimaker PLA: PLA is your standard 3D printing material. It is the most common and easy to print, but it is brittle and prone to breaking when bent. Furthermore, its chemical resistance is not great, and it has a low melting point. Immersing it in boiling water allows you to bend and shape it. So, if your design will be exposed to outdoor sunlight or hot environments, PLA might not be your choice.
Ultimaker ABS: ABS is another popular material choice, but like PLA, it has some drawbacks. While it is more flexible than PLA and can withstand higher temperatures and elements, it is more difficult to print. It is more prone to warping if the print environment is not enclosed and well-controlled, and it must be printed on a heated bed. It also releases uncomfortable fumes that can be irritating to some people, so you should print any material in a well-ventilated room and not directly next to the 3D printer.
Ultimaker Nylon: Nylon is a more advanced material. Its chemical composition makes it susceptible to moisture. So, if you're working in a humid environment, you'll need to keep it in a dry container or put it in an oven to dry it out. A large amount of moisture in the material can significantly reduce quality. However, once you're happily printing with nylon, it's an excellent material. With high impact resistance and low abrasion sensitivity, it's perfect for mechanical parts or components that rub against each other. But like ABS, it can warp and requires controlled ambient temperature!
Ultimaker CPE: CPE is an excellent industrial material with superb dimensional stability. This means it doesn't shrink as much as other plastics, maintaining accuracy closer to the original 3D model's dimensions. This is crucial for tolerances. CPE is also recommended to be printed on a heated bed. Therefore, choosing the right material based on the object you are making is important and should be considered during the early design stages.
Supports
Support material can be your best friend in 3D printing, but it can also cause some problems. It's great for helping you achieve complex shapes that can't be manufactured otherwise, but its drawback is that it's sometimes difficult to remove (unless you're using PVA on an Ultimaker 3). The trick is to avoid using support material as much as possible, but sometimes you need it to achieve your design.
In my design, the main body has a rotating shaft that helps support the main rod and makes it look good.
The curled ends and the top clearly require support, but the support at the top is very thin. This is more concerning because the higher it gets, the more unstable it becomes. This thin support needs to hold its own weight and the curl until it contacts another support. This is very risky and likely to fail.
You can see how thin the support structure is.
So I went back to SolidWorks and designed my own custom support structure. This can also be done in any other design software. This takes up a lot of footprint on the platform and makes the support generated by Cura much more stable. The support structure I designed is offset by 0.3mm from the top, so they can be easily separated. This technical approach is very appealing and makes very difficult cantilevered designs feasible.
Adding supports using SolidWorks.
Before removing supports After removing supports
Inserting Screws
Sometimes, you might need to use more glue to assemble your parts. Screws can be very helpful, but you might not want them to be easily visible. You can hide them in various ways. You can hide screws and bolts so they are only visible from certain angles, or you can create an insert to completely conceal them. You can also stop the print at a certain point, insert the bolt, and then continue, allowing the printer to enclose the hole in the model.
There are two ways to do this. The first is to manually pause the print and insert the bolt, but this is not very precise. Cura has an option that does exactly this. This feature is called "pause at height." It's a bit hidden, but you can find it if you go to the options at the top of the screen. Open "Extensions > Post Processing > Modify G-Code >". Here, select "Add a Script" and then select "pause at height."
Here, you can set the exact height where you want to pause, where you want the print nozzle to move when paused, and the position of the print bed. Make sure you tell the nozzle to stop somewhere that won't restrict your printing.
My advice is to test this feature by creating a small cube with an insert, especially if this is your first time trying it. Remember to turn off the "pause at height" option for your next print.
These are basic techniques you can use to help you create custom supports for more difficult shapes, and to reinforce areas that might need attention, making your designs stronger. This is not an absolute "do's and don'ts" guide, but rather a springboard to help inspire your own designs and creativity. Use this knowledge to help you create excellent projects and develop your own reinforcement techniques. I am excited to see this community push the limits of 3D printing more than ever before. Even if it's just a simple insertion job, someone will learn from it and appreciate it. Happy printing!
The finished 3D printed light fixture.
3D Printed Decorative Light Fixture File Source: https://www.youmagine.com/designs/decorative-light-fixture
Kirby Downey is a designer from South Africa, living in London, who enjoys teaching people how to utilize 3D printing technology and how to push the limits of 3D printing. With over eight years of knowledge and experience in FDM and SLS technologies, Kirby provides everything needed to help himself and others on their 3D printing journey.
Article source: https://ultimaker.com/en/blog/51343-end-use-parts-3d-printing-a-decorative-light-fixture