Abstract
This project focuses on the development of an educational tool for the University of Wisconsin-Madison Makerspace, specifically, Fused Filament Fabrication (FFF) post-processing techniques. A display board with example 3D prints aims to improve students’ understanding of 3D printing post-processing options. The project outlines the goals, design process, 3D printing process used, post-processing techniques, and creation of the final display board. The tool provides valuable insights into common post-processing methods used in the Makerspace, allowing students to have easy access to this knowledge when 3D printing.
Introduction
The Makerspace at the University of Wisconsin-Madison serves as a hub for students engaged in prototyping and project production, addressing both academic requirements and personal projects. This collaborative space facilitates hands-on learning experiences with a wide variety of manufacturing equipment. Currently, there is a requirement for additional physical learning tools to effectively communicate processes to new students. Specifically, there is a need for a tangible diagram illustrating various Fused Filament Fabrication (FFF) post-processing methods. Our project aims to design and create a display that vividly demonstrates the distinct methods and outcomes of post-processing techniques commonly used in the Makerspace.
Project Goals
The project had several important goals for the finished product that would guide design choices throughout. Firstly, the educational tool must summarize and showcase several post-processing techniques, especially those that are commonly used in the Makerspace. There should be some physical representation of each of these techniques which is easy for users to understand. It should also give time estimates for how long each step took to perform so that users can budget their time accordingly. This tool must also be easy to display at the Makerspace. In our experience, having tactile examples is very helpful for users and they seem to have an easier time understanding concepts when they can touch and look over a physical object.
Based on these goals, we determined that the best form for this tool would be a display board with several example 3D prints at various stages of post-processing.
Design Process
Before prototypes could be made, designs for the board and for example 3D prints had to be made. We iterated through several designs for both in order to make the educational tool as helpful as possible. The most commonly used material for FFF printing at the Makerspace is Polylactic Acid (PLA), so we focused on post-processing techniques that work on that material.
Display Board
All the post-processing techniques on the display board must be offered at the Makerspace. This limited the choices to ones that users would have easy access to. With this limit in place, we brainstormed several post-processing techniques that are already commonly used. For example, nearly all FFF prints are printed with support structures that must be removed by the user after the print is finished. Support removal was an important technique to have on the display for this reason. Then, we developed a list of other post-processing techniques that are less commonly used but are very helpful and would be beneficial for users to know about. From our personal experience we determined that sanding, sandblasting, priming, and painting were great options for users to learn about.
Although we intended to only show post-processing tools for PLA, we decided to add acetone smoothing to the board. This technique only works on Acrylonitrile Butadiene Styrene (ABS). However, we chose to add this technique as users sometimes try to use this technique on PLA. Adding it to the board with the stipulation that it can only be used on ABS may prevent users from damaging PLA parts unnecessarily. The finished board layout can be seen in Figure 1.
Figure 1. Display board design and layout.
Example 3D Prints
As Makerspace staff members, we often see users designing parts in a way that is not optimized for FFF printing. In the end, their parts may fail or require significant post-processing that could have been easily avoided by changing certain design features. The example 3D prints that will be mounted to the display board should showcase many common design features so that users can see what post-processing will be needed and can design their parts more efficiently.
Based on our experience, we designed the example part shown in Figure 2 to have many common design features such as overhang with support, through holes without supports, embedded text, a rounded top surface, sharp edges, and flat surfaces. It would be printed in the orientation shown in Figure 2 with the round surface facing upwards. This part was designed so that only the large overhang on the right side would require supports.
Figure 2. Example part design.
3D Printing and Post-Processing
Once the designs were approved by the team, they were printed using the Bambu Lab X1-carbon FFF printers at the Makerspace. In order to use these printers, the 3D models of the designs would need to be sliced in the Bambu slicer. This slicer has many customizable parameters for printing that we experimented with. Once we found the optimal parameters, we began post-processing the parts for the display board.
Print Parameters
Since this is an educational tool, it is not important that the 3D printed parts have particular strength against a load or minute detail. What is most important for this project is that they print quickly and cheaply, while maintaining a basic standard of quality among all parts. To increase speed, a layer height of 0.2mm was chosen. This makes sense as our part does not require small intricate details.
As previously mentioned, the parts did not need to be incredibly strong or tough, so low infill would be the best choice. We chose 10% infill in order to minimize material quantity and print time. However, we also had to choose which type of infill to use. In order to determine which type of infill was best, we printed two prototypes, one with line type infill and one with lightning type infill. The differences between these types can be seen in Figures 3 and 4. Lightning type infill significantly reduced the material quantity from 65 to 43 grams and reduced the print time by 6 minutes. However, we wanted to ensure that the lightning type infill would not make the parts too weak or make the design susceptible to failure.
Figure 3. Cross section of the example part with line type infill.
Figure 4. Cross section of the example part with lightning type infill.
Additionally, we wanted to determine what color to print our parts in so that the changes would be most visible to users. We printed one part with a silver PLA and another in blue. These sample parts can be seen in Figure 5.
Figure 5. Two sample prints before support removal.
Based on the samples in Figure 5, we decided that the blue PLA was the easiest to visualize on the board and that the lightning infill worked very well in printing. The matte finish on the blue PLA was much nicer and had a better surface finish on the embedded text.
However, we noticed that the supports were very difficult to remove on these sample parts. Since we would need to remove the supports from many parts for the board, we needed them to be easier to remove. So, we also changed the support offset settings to increase the space between the support and the finished part. This cut the time to remove supports in half.
Post-Processing
As we post-processed our prints to each stage, we made sure to record the time needed for each post-processing technique. Giving the time for each technique was an important part of our display board so that users could budget their time better.
The first technique was to remove supports. By changing the support offset settings, we were able to remove the supports from the example parts in just 30 minutes. To do this, we used pliers and flush cutters. Both of these tools are available in the Makerspace. The result of this technique can be seen in Figure 6. The overhang of the part was still quite rough where the supports came into contact with the finished part.
Figure 6. Example part for support removal.
The next technique was sanding. In order to remove the roughness on the overhang and to eliminate the layer lines on the rest of the part, we used 120 and 180 grit sandpaper. For tight areas such as the triangular and round through holes, files were used. This process took only 10 minutes. Although layer lines are still visible, as seen in Figure 7, the surfaces are much smoother. This technique is very commonly used by Makerspace users, but they often do not increase the grit and perform a secondary sand.
Figure 7. Example part for sanding.
As an alternative to sanding, a sandblaster could be used. To use a sandblaster, the part is placed in the chamber and high grit sand or garnet is sprayed over the surface. The outer surfaces and edges become very smooth in much faster time frames than with hand sanding. Tight holes are easier to sand this way. The part in Figure 8 is much smoother than the part in Figure 7, including around the tighter holes even though it only took 5 minutes longer. Most Makerspace users are unaware that they can use a sandblaster instead of sanding by hand. For parts like this with no small, delicate pieces, sandblasting can be a great alternative.
Figure 8. Example part for sandblasting.
Once sanded, if the part is made of ABS, it can be smoothed with acetone. Using a vapor chamber, the part in Figure 9 was smoothed with acetone vapor. This part is ABS as PLA cannot be smoothed with acetone, it will melt. Embedded text is not preserved well using this method, but the outer surfaces are very smooth. This process took 2 hours to complete but only required active participation for about 15 minutes. The part can simply sit in the vapor chamber for the remainder of the time. Similar to sandblasting, many Makerspace users do not know that they have access to a vapor chamber to perform acetone smoothing.
Figure 9. Example part for acetone smoothing.
The last two post-processing techniques are priming and painting. Using automotive primer, the part in Figure 10 was sprayed all over the surface. The primer will fill imperfections in the surface, allowing for a very smooth surface finish. Any primer can be used, such as Bondo or some other wood filler. Most users at the Makerspace do not prime or paint their parts, however, many complain about visual layer lines on their finished assemblies and want to make their 3D-printed parts look more finished. Priming and painting are great techniques to achieve this final look. Priming only took us 10 minutes, meaning it is a very fast process that can significantly improve the look of 3D-printed parts. Additionally, the Makerspace usually has some primer and spray paint that students can use if they ask for it.
Figure 10. Example part for priming.
We wanted to highlight the difference between a part that has been primed before being painted and a part that has just been sanded on our display board as users often ask what the difference is. As seen in Figure 11 (a), the part that has been primed first has an incredibly smooth and shiny surface finish on the outer surfaces and on the lettering. However, the part with no primer (Figure 11 (b)) is matte with visual layer lines and imperfections. It is important to note that both parts still held paint well and the process only took 10 minutes for both.
Figure 11. Example parts for painting on primer (a) and painting on sanded part (b)
The Final Display Board
The display board was made using the CNC router at the Makerspace. This allowed for the board to be precisely sized and to have embedded text in the wood. It was designed to hang on an existing shelf in the Makerspace 3D printing area so that users could easily see and touch the example parts.
The board was cut out, sanded, painted, and sealed so that it would look the same as the design and last for a long time. Using wood for the board meant it was strong and easy to mount into place as shown in Figure 12. The text with extra instructions and time for each process would not fit on the board, so we created a QR code sticker that leads to a document with more information on each technique.
Figure 12. The final display hung in the Makerspace 3D printing area.
Discussion
The development of the FFF post-processing educational tool presented in this project has significantly enhanced the educational resources available within the University of Wisconsin-Madison Makerspace. By focusing on creating a tangible display board showcasing various FFF post-processing techniques, we aimed to provide students with practical insights into 3D printing workflows. This tool not only serves as a visual aid but also facilitates hands-on learning, allowing students to interact with physical representations of post-processed prints. The selection of techniques featured on the display board was informed by their relevance to common Makerspace projects and their potential to enhance print quality and aesthetics. Moving forward, this project sets the stage for continued innovation in educational tools within the Makerspace environment, emphasizing the importance of user-centered design and effective communication of complex manufacturing processes to students.
Conclusions
In summary, the development of the FFF post-processing educational tool has significantly improved learning opportunities within the University of Wisconsin-Madison Makerspace. By creating a practical display board showcasing various FFF post-processing techniques, this project offers students hands-on experience and a clearer understanding of 3D printing workflows. The tool’s success highlights the importance of accessible educational resources in fostering skill development and innovation in modern manufacturing. Moving forward, continued efforts in educational tool innovation can further enrich student learning and promote creativity within the Makerspace community.