Project: Reverse engineered dental X-ray component
Location: Ixopo, KwaZulu-Natal
Services: Reverse engineering, custom manufacturing, 3D printing, prototyping and design refinement
The Challenge
A dentist from Ixopo contacted Printer Under The Stairs to ask whether we could produce a replacement dental component using 3D printing. The original component was used during dental X-rays and included a circular plastic section that the patient bites onto while the X-ray is taken.
The dentist explained that buying the original replacement component cost approximately R2,500. That prompted her to investigate whether a more accessible, locally manufactured alternative could be produced instead. We agreed to see what was possible.
We did not receive a CAD file, an STL file or a digital model ready to print. We received a physical sample consisting of the stick and the circular disk, and had to work backwards from that sample.
The physical stick and circular ring supplied as the reference for the project.
Finding a Way Forward
The first step was to examine the physical components and understand how they fitted and worked together. The sample gave us the reference we needed to recreate the parts digitally and work out how the design could be manufactured.
CAD model recreated from the physical sample.
The two printed components were made from PLA. Their approximate finished sizes are shown below.
| Component | Material | Approximate finished size |
|---|---|---|
| Stick component | PLA | 146.27 × 62.27 × 3.8 mm |
| Circular ring or bite component | PLA | 87.55 × 77.70 × 6 mm |
CAD drawing of the circular ring component.
CAD drawing of the grooved stick component.
The Design Challenge
The mechanism made this more complicated than a straightforward print. The stick had grooves that allowed the circular disk, or ring, to move up and down, giving the option of using different positions. Recreating that relationship between the grooved stick and the moving ring was an important part of the design.
A mechanism like this is not as simple to manufacture through 3D printing as a basic solid component. The parts need to be shaped accurately enough to fit together, while still allowing the ring to move between the available positions. Simply reproducing the general appearance of the sample would not have been enough.
That meant the physical sample had to be reverse engineered with the assembly in mind. The design needed to be adjusted and tested in practice, rather than treated as a single print.
From First Print to Working Model
We produced an initial version and tested how the components fitted and worked together. That first version showed that getting the grooves right was particularly challenging. We then made changes to the design and produced several revised versions, using each iteration to improve the fit and movement of the ring.
After the various revisions, the dentist indicated that she would use the ring at a selected position rather than repeatedly moving it up and down. Repeated adjustment created friction in the mechanism and could cause the ring to get stuck. Using one position was a practical way to use the model without relying on the ring being moved continually.
The important part of the project was not the first print. It was the practical problem solving between the physical sample, the digital design, the first version and the revised versions.
The Result
The final version was not a perfect replica of the original commercially manufactured component. It gave the dentist a working model for the project, with the ring used at one selected position rather than moved repeatedly. The project demonstrated that a niche plastic component could be locally manufactured as an alternative to the approximately R2,500 original replacement.
The completed PLA stick and circular ring produced for the project.
The original sample was not 3D printed, and that difference mattered. 3D printing can be useful for custom components and replacement parts, but mechanisms involving sliding fits, grooves and moving parts can have practical caveats. The manufacturing method, tolerances and intended use all need to be considered, and a locally manufactured alternative with a lower cost may involve compromises.
The result came from reverse engineering a physical sample, working through a more complicated adjustable mechanism and refining the design over several iterations. It was a specific manufacturing and prototyping result, not a claim that every dental component can be reproduced in the same way.
Key Outcome
- Reverse engineered from a physical sample, with no CAD or STL file supplied.
- Several design revisions were required to reproduce the grooved, adjustable mechanism.
- A PLA working model was produced, with a practical compromise around the ring’s adjustable movement.
What This Project Demonstrates
This project shows the kind of practical manufacturing problem Printer Under The Stairs can help investigate. A customer may have a physical sample, a component that is difficult to source or simply a requirement that needs a physical solution. They do not necessarily need to arrive with a CAD file or know exactly how the part should be manufactured.
The work can involve reverse engineering the sample, assessing manufacturability, producing a first version, testing the fit and movement, refining the design and making a working model or small batch. That approach is useful for niche replacement components, custom parts, prototypes and situations where an existing replacement is expensive or difficult to obtain.
The value is not just in producing a printed object. It is in working through the design and manufacturing problem until there is a practical result, while being honest about the limitations of the chosen process.
Scope of This Case Study
This was a custom manufactured working model, not a medically certified or approved product. This case study makes no claims about clinical use, sterilisation or patient safety.
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