For this project, I set out to 3D print and post-process two identical anatomical eye models using Polylactic Acid (PLA) filament. The post-processing steps included sanding, priming, and acrylic painting to achieve a hyper-realistic finish.


Step 1

I chose an anatomical eye model from Thingiverse (Link) and downloaded the STL file.


Image of 3D model STL file


Step 2

I used Bambu Studio Slicer to prepare the file for printing. The slicer allowed me to optimize the print settings for high quality, position the model correctly—since the underside of the eye had a flat base, I didn’t need additional support. I wanted to also check that I had the appropriate layer height (0.15mm), Wall thickness (1mm), and Infill density (15%)

Some useful Commands in Bambu Studio:

• • Scaling: Pressed “S” to adjust size.
  • Slicing: Used “Slice Plate” to compile the model and estimate print time.

• Final Adjustments: Verified parameters to ensure smooth slicing before printing.

I first printed the eye model at the default scale provided on Thingiverse to see how it would turn out.

Picture of Initial Print

However, I quickly realized that the model looked too small—approximately the length of two fingers. To improve painting details and better match the proportions of a real anatomical model (based on my interpretation of the picture on thingiverse)  I decided to scale it up by 3x.

I thought this was needed since the rubric emphasizes that “the part should be an appropriate size, scaled correctly, and individual features should not be too small to be identified or handled.” In addition for verification and anatomical accuracy, I consulted OEDK TAs for guidance on selecting the most appropriate size.

(Image of anatomical model from thingiverse)

Step 3

I sent the sliced file to Printer #5, an Fused Deposition Modeling (FDM) printer at OEDK.

Material Used: PLA filament (White)

Estimated Print Time: 28 minutes for both models printed on the same plate. (1x scale), 3hrs (3x scale)

Printing Outcome: The prints had minimal layer lines, making post-processing smoother.


Image of the 3D printer in action!

Step 4
After removing the prints, I began the sanding process to remove rough edges and improve paint adhesion. My process started with a Coarse Sanding (60-grit sandpaper) for smoothed rough layer lines, and then I transitioned into a fine Sanding (120-grit sandpaper) to achieve a polished finish.

Step 5:
To prepare for painting, I applied a primer to create a smooth, paint-ready surface. The application method I used was:

– Sprayed in a well-ventilated outdoor space at OEDK.
– Followed safety precautions: Shook the can properly, checked temperature/humidity, and used a smooth back-and-forth motion.
– Drying Time: 24 hours before painting.

Step 5

Using acrylic paint, I detailed the eye model to resemble real anatomical structures on thingiverse with minor adjustments since not all angles were shown on the picture online. 

Red: Highlights the eyelids and surrounding area.
Blue: Used for the upper and lower outlines, adding depth.
Yellow: Represents the iris.
Black: Defines the pupil center, creating contrast.
White: Forms the sclera (whites of the eye).
Pink: Found on the back and sides, mimicking the inner eye tissue/conjunctiva.

 

Step 6
To protect the paint and enhance realism, I applied a glossy clear coat, giving the eyes a wet, lifelike finish. I sprayed outdoors, following proper ventilation and drying guidelines. I let this sit for a day to process and dry!

Below is my cost analysis:

Cost Type	Item	Price	Source	Quantity Used	Total Cost
Materials	PLA Filament	$21.64 (1kg Spool)	AMAZON LINK	At 3x scale, likely ~200g (20% of spool)	$4.33
	Sandpaper (60/120G)	$17.55 / 25 Sheets	AMAZON LINK	Approx. 1/4 of an A4 sheet (~4% of a full sheet)	$0.70
	Primer Spray	$11.99 (10 oz Can)	AMAZON LINK	~15% of the can	$1.80
	Acrylic Paint Set	$24.99 (36 Colors, 2oz Bottles)	AMAZON LINK	Used 6 colors (~16.7%)	$4.17
	Clear Gloss Coat	$9.99 (100 mL Can)	AMAZON LINK	Used ~20% of the can	$2.00
Labor	Prototyping Engineer (You!)	$36/hr	LINK	Worked 10 hours	$360
Overhead	Facility Cost (Machine Time)	(15.60 cents per kWh)	LINK	3.5 hours of 3D Bambu Printer time	$0.19
Design	Engineering & Development	$43.51/hr	LINK	10 hours worked	$435.10
Total Estimated Cost	$808.29

Picture of clean table: