For the final project, we were assigned the task of designing a pelvic frame prototype to train individuals to do cervical examinations.
In the first part, we focused on creating the base of the pelvic frame. We sourced thick wood from the wood workshop to ensure a sturdy foundation. A band saw was utilized to cut the wood to the desired dimensions and to shape the slanted portion of the ramp, achieving the necessary angle for the base. Cutting the angled section proved to be the most challenging aspect, as we had to carefully cut smaller rectangles to accurately achieve the 20-degree angle.
Image 1: The base, which includes a plane and a ramp.
Next, we used an orbital sander to smooth the edges of both components for the base before wood gluing them together.
Image 2: Orbital sanding the base.
In the second phase, we focused on designing the pelvic frame using Adobe Illustrator to cut the shapes with the Laser Cutter. Each file required approximately 40 seconds to a minute for completion. The first piece consisted of three shapes, the second piece included two shapes, and the third piece was made up of a single square, leading to a total cutting time of about 15 minutes. The engraving for each number was performed at a speed of 60 and a power of 80.
For pieces that involved two or more cut wood components, we utilized wood glue and clamped them together for 30 minutes to ensure proper adhesion.
Image 3: Prepping the prints for the laser cutter.
Image 4: Laser cutting the pelvic frame.
Image 5: Using wood glue to attach the pieces together.
Two pieces had edges that did not fully cut through in the first round of the laser cutter. Therefore, this required us to re-run the laser cutter or use 800 and 400 grit sandpaper to achieve the desired precision.
Image 6: The laser-cut pieces of the pelvic frame and the sandpaper.
Part three involved 3D-printing the cervix model holder using the Prusa printer. We utilized a C-shaped holder sourced from Thingiverse, printed with TPU to allow flexibility to fit the model securely within the diameter of the holder. The printing process took 35 minutes and provided a balance of flexibility and rigidity, effectively preventing the model from moving. Afterwards, we post-processed the print by sanding the edges of the holder.
Image 7: The preview of the cervix model holder on Prusa Slicer.
In part four, we 3D-printed eight L-brackets to support the pelvic frame pieces in an upright position on the base. The L-shaped bracket, also found on Thingiverse, required 2 hours and 10 minutes to print with PLA material on the Bambu printer. We attempted to print side wall attachments with the brackets; however, the initial PLA version was too small and rigid. We then created a larger TPU version; however, they turned out to be too bulky and flexible.
Image 8: The preview of the L-brackets on Bambu Slicer.
Image 9: The 3D-printed L-brackets and cervix model holder.
In part five, we focused on assembling the pelvic frame, base, and cervix model holder. We drilled 6 screws (18-8 Stainless Steel, Phillips Head, 6-32 Thread, 3/4″ Length) into the base for stability. The frame pieces were designed to be removable for easy storage, like the initial prototype with stainless steel wing nuts. Additionally, the cervix model holder was securely super-glued onto frame 3 to hold the cervix model. The toughest part with this phase was finding the proper screw size, length, and nut to secure the pieces together, but we got it!
Image 10: The final assembly of the pelvic frame prototype.
Image 11: The final assembly of the pelvic frame prototype (side profile).
Overall, I found the process of assembling this multi-piece project enjoyable, and I wish I had more time to explore creative design options for the prototype. To enhance our design, we could consider implementing a mechanism that allows the pelvic frame pieces to slide vertically into a slot, complemented by a collapsible short side wall that has the slots.
Image 12: Clean workspace
Cost Analysis:
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials
|
Wood (0.4 cm x 50 cm x 44 cm) | $15.99 | Rockler | 1 | $15.99 |
| Green TPU (1 kg) | $0.80 / ounce | Amazon | 0.85 | $0.68 | |
| PLA filament | $19.99 / kg | Bambu Lab | 0.01 kg | $0.21 | |
| Post-processing tool (Sandpaper) | $12.68/20 pcs of 9×11 320 grit paper | Amazon | ⅛ sheet | $0.08 | |
| Super glue | $7.48 / 15 g | Home Depot | < 0.5 g | $0.25 | |
| Wood glue | $4.37 / 8 oz bottle | Amazon | < 0.05 oz | $0.22 | |
| Wing nut | $1.52 / nut | Home Depot | 16 | $24.32 | |
| 3/4″ passivated screw | $0.13 / screw | Bob’s CB | 16 | $2.08 | |
| Phillips head screwdriver | 7.97 | Home Depot | 1 | $7.97 | |
| Labor | Laser cutter operator | 19 / hr | ZipRecruiter | 1 hr | $19.00 |
| Prototyping engineer | 25.91/hr | Indeed | 7 hr | $181.37 | |
| Overhead | Laser cutter usage cost | 0.14/hr | Accurl | 1 hr | $0.14 |
| 3D printer usage cost | 0.21/hr | Prusa | 2 hr | $0.42 | |
| Band saw operating cost/blade usage | ~$90 / day | Peterson Sawmills | 1 day | $90 | |
| Hand drill operating cost | $0.072 / hr | Slashplan | 10 minutes | $0.01 | |
| Total | $342.74 |
