Week 5 - 3D Scanning and Printing
For this week, the goal was to scan an object, using the lidar on our phones and also to 3D print an object that can only be made additively. Along with that, we also are tasked with testing design rules for our 3D printers.
3D Printing
To start my quest to 3D print and object that can only be made additively, I first had to understand what exactly that meant. I started with looking it up on Google and found this website. From this website, I found that additive manufacturing builds object by adding material on layer by layer, similar to the way a 3D printer lays one layer of filament on each other until the object is build. On the contrary, subtractive manufacturing removes material to create parts, similar to the way CNC machines cut out material to create a shape. Additive manufacturing is easier and faster to setup than CNC machining, while subtractive manufacturing is for higher volume projects, while it provides tighter tolerances.
Then, to generate ideas, I looked to ChatGPT and told it to list out ome ideas on what objects that could be made additively, but not subtractively. Here are the AI Logs. I ended up deciding on a Captive Ball design where a ball is encased inside a cage-like object.
I then went to Thingiverse to find some pre-made designs for inspiration. I looked up "ball inside" and this is the design that I based my design off of.
Designing the Design
To make this object with a ball inside of it, I first made a large ball that would create the round nature of the shell. I wasn't worrying about the exact dimensions of the design because I knew I could always scale it up later in Bambu Studio to my desired size. Then I offset all 6 of the planes, creating an almost cube like shape. Then, created a large circle (doesn't matter how big because I am just taking off material on the sides) on each of the offset planes.
After I had created the sketches, I used the extrude tool (shortcut = E) to extrude all of the sketches about 2mm inward, activating the cut mode and making flat surfaces on the ball.
After that, I need to shell out the object, so in order to create the round inside, I created a ball and set the operation to cut in order to shell it out.
Then, to give it a more open look, I decided got rid of the flat surfaces on each opening and extruded it negatively (I cut it).
Lastly, I needed to add the ball in the middle of the shell. Since I had created the shell from the origin point, I could easily add the ball in the middle by going to Solids>Create>Sphere and then dragging the blue arrow from the middle to increase the size to a little smaller than the shell, again not worrying about specific sizes.
Here is the final design.
3D Printing the Design
To start 3D printing, I first exported the stl file into my computer's files by changing the file type in the export tab and exporting to my desired folder. I then opened Bambu Studio and under the prepare tab, I added my file with Ctrl+i and selected my recently saved stl file and changed the size to a reasonable size that wouldn't take up too much time. For time's sake, I used Bambu's preset for Optimal and turned on tree supports to hold the center ball.
To print it, I pressed "print plate", selected the Bambu Mini I was using, and pressed send. After I had overlooked the first layer successfully, I was able to leave the printer alone. Here is it printing.
video
Here is the print before post-processing.
Here is the final ball inside a shell after post-processing.
I am personally very happy with how this turned out because it is surprisingly fun to fidget with. It could not be made subtractively because of its internal geometry not allowing a subtractive tool not being able to access the bottom of the inner ball. If it were to be made subtractively, it would have to be made with separate parts and then later assembled.
3D Scanning
To 3D scan an object accurately, I would have to buy a lidar scanner worth THOUSANDS of dollars. If I were to buy that, not only would I be broke, I wouldn't be able to buy my $50 gaming digital cosmetics. That's a big no-no. So, I guess I'll I have to settle with my regular phone which has a built-in lidar scanner.
To do this, I just simply went to the app store on my phone and looked up 3D scanner. Because I am a trusting person, I just hope it's not a virus and I download the first appealing one I see: Polycam.
Turns out I was right to trust this. It was very self-intuitive and not complicated at all. I first pressed the button to scan and object and it was smooth sailing from there. All I did was walk slowly around the object I chose: a Coca-Cola can. After the second try, I was able to successfully create a semi-acceptable 3D rendering of the bottle. Something that I didn't like about this app was that it would scan the ground along with the object and was not able to recognize what exactly I was scanning.
Although I did not do it, there was an option to save the scan as and stl file and from there I would be able to 3D print it. However, it costed money and as I said earlier, there are more important things to spend money on.
Group Work
For this week's group work I did the infill test, testing the affect of infill percentage on durability. What I learned from the group work was that when you hit things with a hammer, things tend to break. However, the greater the density, the greater the impact an object can take.
Reflection
After completing this week's work, I think that this week was overall pretty fun. I mean, I got to break stuff so that was pretty exciting. I also think that because of this week, I have a good semi-in-depth understanding of subtractive and additive manufacturing and when to use them. The scan was also pretty cool because I was able to create a 3D model within 5 minutes all with the help of an app on my phone. It makes me ponder on how much our modern technology has really advanced.