As soon as I saw the LUCIA cervix holder and the pelvic frame in class, I knew I was going to be doing this mostly on the laser cutter.
First, I tried to understand the characteristics of the LUCIA model, and what I wanted to keep or change.
- The model was tilted, rather than parallel to the floor. I assume this was to maintain the average pelvic tilt for anatomical accuracy. I decided to keep this feature in.
- The model had 3 pieces of wood that were perpendicular to the pelvic frame – the vaginal opening, and two pieces of wood that held up the cervix holder. I wanted to reduce the number of wood pieces (excluding the base) to 2.
- I wanted the model to be intuitive to piece together, and I aimed to keep the design simple.
After some brainstorming, I created a prototype drawing.
Figure 1.
Initial Prototype Drawing
I decided to create a locking mechanism for the cervix holder. The cervix itself would have two attachments: a winged circle that fits perfectly in the winged hole in the cervix holder, and a broad base that can not go through the hole in the cervix holder. The initial idea was to have the gap between the two attachments be equal to the thickness of the cervix holder, to give the cervix a tight fit. However, that did not happen – I will come back to this later.
As I was making the design in Adobe Illustrator (this was my first time using it, so that was a challenge), I realized that the hole cannot be 3 cm to mimic the cervix, as the attachment would add to the diameter. The diameter of the central hole in the ceramic holder is 3.5 cm, whereas the hole in the attachment itself is 3 cm. Once I created the Adobe files, I cut them up using the laser cutter.
Table 1
Dimensions of the Components
| S.No | Component | Width (cm) | Height (cm) |
| 1 | Vaginal Opening Wood | 12 | 13.4 |
| 2 | Vaginal opening eclipse | 3 | 6 |
| 3 | Height of base | 12 | 3.15 |
| 4 | Pelvic floor base | 12 | 9.27 |
| 5 | Cervix holder wood | 12 | 13.4 |
| 6 | Central circle in the cervix holder | 3 | 3 |
| 7 | Wings in the cervix holder | 4.64 | 4.22 |
| 8 | handle for base | 1.57 | 2.8 |
| 9 | Numbers “1” and “2” | 1.05 | 1.8 |
Figure 2
Adobe Laser Cutting File
Now I 3D printed another cervix to attach my attachments and test out the cervix holder. I superglued the pieces together. Immediately, I noticed an issue – the thickness of the wood was ¼”, but this fell right on the embossed text “1 B” on the cervix, which meant that I could not place the attachments according to my initial idea of keeping a tight fit.
So that was the first issue with this prototype. If I redid this prototype, I would modify the cervix to have more height after the embossed text (or move the text itself), so that the attachment does not overlap with the text.
Figure 4
Locking Mechanism for Cervix
Figure 5
Locking Mechanism for Cervix – Front View
Figure 6
Locking Mechanism for Cervix – Back View
Now came my second prototype dilemma: I did not know how to attach these pieces of wood to each other. I thought I could use L brackets and wing nuts (bolts?) like the actual LUCIA model. But I could not find any in the OEDK. I was considering 3D printing the L-brackets.
After some advice, I decided to 3D print press fit slots instead. I used AutoCAD to make the slots. Note here: Before this project, I had used CAD software for all of 10 minutes. So it took me 3 hours (!!!) to make the simple design, but I finally made it! Then I 3D printed the slots. I made the gap in the slot equal to the exact thickness of the wood – however, the fit of the slot was too tight. The slots almost snapped off the wood. If I redid this, I would make the slots a bit wider.
Figure 7
Slot Files in Bambu Slicer
I glued the base together with Elmer’s Glue. At this time, I noticed another mistake I made. Where I marked the perpendicular pieces of wood with numbers, I forgot to mark the base. Making the markings useless. I decided to go on with a Sharpie and mark the numbers on the base.
I also noticed that I had accidentally messed up the measurement of the wood in Adobe, as the width of the base was slightly less (11.35 cm, instead of 12 cm) than the width of the perpendicular pieces of wood, when I had intended them to be the same. Another mistake is that the base should have been longer than I initially calculated, as the height wood piece was not attached to the very end (as it had in my calculation).
Figure 8
Gluing Base Together
I decided to laser cut the base again, this time with the corrected dimensions and the numbers engraved in them. I also added little cuts in the base to indicate when the slots should go, to make it easier to keep the wooden pieces parallel to each other.
Figure 9
Laser Cutting Base Again
Figure 10
Cuts in the Base to Guide Placement of Slots
I also 3D printed L-Brackets this time (I made the CAD files myself! It was so quick this time now that I knew more about how AutoCAD works) and decided to screw the base together (instead of simply gluing it) to improve stability.
Figure 11
Drilling the Wood
Figure 12
Pelvic Frame Attached with L-Brackets
As can be seen, the brackets were attached a bit crookedly (I have never drilled before either – so a lot of first times in this project!).
Finally, I attached everything together, and voila <3
Figure 13
Complete LUCIA Prototype – Angled Front View
Figure 14
Complete LUCIA Prototype – Angled Back View
After I was done with everything, I noticed a blunder. The most major blunder so far – I flipped the position of the vaginal opening and the cervix – so the pelvic angle flipped to 70 degrees, instead of 20 degrees.
Sigh…. It was too late to fix now unless I re-did the base again, so I decided to acknowledge my mistake and leave it be.
Issues to address to improve the prototype:
- Make the lock a tighter fit, so that the cervix is more stable. The can be done by making adjustments to the cervix itself so that the embossed text is not in the way.
- Make the press fit slots with a more flexible material so that the slots are resistant to breaking.
- Be careful when it comes to putting everything together, and not mess up the order of the wood (seriously that was pretty bad – I must have been sleep deprived when I put everything together)
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 |
| White PLA (20 m) | 12.99 | Amazon | 0.06 | 0.78 | |
| Elmers Glue (20ml) | 0.99 | Lowe | 0.1 | 0.09 | |
| Super Glue (5 ml) | 1.25 | Target | 0.2 | 0.25 | |
| Phillips screw (2) | 0.20 | HOCL | 2 | 0.40 | |
| Bolt (2) | 0.06 | One Source Supplies | 2 | 0.12 | |
| Drill | 55.99 | Amazon | 1 | 55.99 | |
| Labor | Laser operator | 19/hr | ZipRecruiter | 1 hr | 19 |
| 3D print engineer | 20/hr | ZipRecruiter | 2 hr | 40 | |
| Overhead | Cost of using Laser cutter | 12.73/hr | AlphaLazer | 1 hr | 12.73 |
| Cost of using 3D printer | 3/hr | eufymake | 2 hr | 6 | |
| Total | 151.35$ |
Note. I did not count the additional 3D print cervix I made in the cost analysis, as that not part of the protype itself.
Here is an image of my last workspace:
