Learning how 3D printers work and then having an opportunity to apply our knowledge through this assignment, was truly a great opportunity for me to be creative and have a bit of fun!

For this assignment, we were presented three different options, in terms of types of 3D objects we could make, however, I decided to go with making the 3D impossible object.

Steps I took to produce my 3D printed heart infinity cubes: 

1. I first started to look for potential impossible objects by drawing inspiration from past classes and objects that they had printed via the engi210 blog. I then went to Google and searched impossible 3D printed objects, and came across this Valentine’s Day heart themed infinity cube on printables.com (https://www.printables.com/model/1179447-micro-valentine-infinity-cube/files). As soon as I saw the picture of the object, I knew I wanted to create this as its theme matched the upcoming Valentine’s Day holiday, and was also a fun object to play with.

Here’s a picture of the STL file:

2. Once I had chosen the object I wanted to print, I downloaded the STL file to my desktop and brought it to the OEDK to input into the Bambu and FormLab slicer programs. I had also decided at this point in the process, that I wanted to try to use both the FDM and SLA 3D printers for this project.

3. I first started with printing my 3D printed objects in the Bambu printer using white PLA as my filament. I uploaded the file from my desktop to the OEDK computer using a flashdrive, and used the Bambu slicer program, to scale my 3D printed object down to 50% (measurements of: x=0.5 in, y=1 in, and z=0.25 in) of the original design, as I thought it might be too big to fit in the gum ball capsule at its normal scale. I then sent it to the Bambu printer, and I watched it until the first layer of the print was laid.

4. The print took a total of 20 minutes. The results of the print are below:

While the pictures might make the scale look better, in person, the print was tiny, teaching me that I needed to keep the print at its original scale. I then went back to the Bambu printer and printed the object at the original scale size. Some observations I had made following this iteration were that the object was pretty small and fragile. One of the connectors broke after moving the hinges on the object a bit, but I was able to  fix it with super glue. However, when looking at the object, I could see the details pretty well. This object would definitely fit in the gum ball capsule, but I can try to make it the original print size.

5. When printing the second iteration of the object, it took 0.28 oz of PLA filament, took 31 minutes to print, and was scaled to its original size (measurements of: x=0.86 in, y=1.73 in, and z=0.42 in). Below is the final product of the second iteration print:

Some observations I had after printing this iteration were that it is small enough to fit in the gum ball capsule. It feels pretty good when moving it around and can move well on the hinges. The heart shape is also pretty clear on the 3D print.

6. For the next 3D print, I focused on printing the object using SLA, instead of using the Bambu printer with PLA filament. I was honestly pretty nervous about using the SLA 3D printer after learning about the 3 steps that are needed to get the print (printing, washing, and curing).  However, I was able to import my object easily into the FormLabs slicer on the OEDK computer, and did not have to scale anything, since I determined the original scaling measurements were the optimal size for the object. For one print, I utilized 9.34 mL of the Clear V4 filament. This print took about an hour. After which I transferred the object into the washer and set it to wash in isopropyl alcohol for 30 minutes. I then transferred the object to the UV curing machine set at 60 degrees celsius for 30 minutes. The product of the SLA print is shown below:

While this print looked a lot clearer in terms of the heart outlines on the object, I was unable to separate the moving pieces of the object. Through this, I was able to learn that SLA 3D printing is not a good option when an object has parts that are supposed to be movable, such as this infinity cube, as the resin becomes sticky and is unable to be separated after curing.

7. I then moved into sanding all of my 3D prints (both from the Bambu printer and SLA), trying to make all of them as smooth as possible before going in with paint to give them color. I utilized 80 grit and 220 grit pieces of sandpaper. Pictured below is the sanding process:

8. After sanding and making sure that the objects did not have particles left on them, I utilized the acrylic paint in the violet color to make the objects look visually more interesting. Painting such a small object required smaller paint brushes to get a more even finish, however, this was not available to us in the OEDK, and therefore, I tried to make use of a sponge brush that seemed to do better than the bristle brushes. Pictured below is the painting process:

The SLA printed object was not painted as I was unsure if the paint would adhere to its surface, and also liked the clear color of the object.

9. I then placed my objects in 5 different gum ball capsules and then were ready to turn in.

Picture of my clean workspace:

Reflections from the Process: 

1. I learned how to use 3D printers (both the Bambu printers and the FormLab printers).
2. I learned that SLA 3D printing is not optimal for objects with moving parts, as the resin is sticky and will not become separable after printing.
3. I learned how to be creative and have fun with prototyping.

Cost Model: 

Cost Type	Cost	Price	Source	Quantity	Total
Materials	Filament (PLA)	$19.99 per roll (8.8 oz)	us.store.bambulab.com	1.12 oz (13% of roll)	$2.60
	Filament (Clear Cast Resin)	$149 (1000 mL)	Formlabs.com	9.34 mL (0.9% of bottle)	$1.34
	Gumball Capsules	$16.69 (30 capsules)	amazon.com	5 capsules	$2.84
	Sandpaper	$12.25 (20 sheets of 9×11)	amazon.com	1 sheet	$0.61
	Sandpaper	$21.94 (20 sheets of 9×11)	amazon.com	1 sheet	$1.10
	Game Color Ink (Purple)	$26.53 (set of 8)	amazon.com	0.15 fl oz of purple color	$0.87
Labor	Prototyping Engineer (You!)	$36/hour	ziprecruiter.com	2 hours	$72
	3D Printing Operator	$19/hour	ziprecruiter.com	3 hours	$57
Overhead	Facility Cost (Machine Time)	$120/week	polyprinter.com	1 day	$17
	Quality Control	$39/hour	ziprecrutier.com	1 hour	$39
Design	Engineering and Development	$19/hour	ziprecruiter.com	1 hour	$19
Total Costs: $213.96