Cranial Reconstruction
This case study demonstrates the ISF process being used in a medical context, and is representative of many similar applications categorised by the need for per-patient customisation.
Background: titanium implants for cranioplasty
The human skull protects the brain, and surgical operation may be required if a defect has been brought about in the skull by an injury or a previous operation.
In cranioplasty, materials are used to fill a defective area. A commonly used material for the cranial plates fixed to the skull is titanium, which is robust, highly biocompatible, infection-resistant and non-corrosive.
Current methods to manufacture titanium-based cranial plates include casting, manual shaping and rubber press forming. All of these rely on customised casting moulds, templates or forming dies, which increases costs and lead times. More recently, additive manufacturing has been considered, but this approach has its own major drawbacks of insufficient material properties and a high cost.
For more details, see Cranial Reconstruction using Double Side Incremental Forming.
Key Points
Missing shape reconstructed from NURBS approximation
Cranial plate surface geometry generated for DSIF
Toolpath generation: peripheral support compared to local support
Machine developed for DSIF
Finished part and trimmed cranial plate
Comparisons suggest a better surface finish with peripheral support than with local support
Benefits
ISF could remove the need for a mould or die in the manufacturing process, reducing costs and manufacturing times.
Unlike additive manufacturing, ISF maintains the material properties of a sheet formed with a conventional die-based method.
Viability
The paper Cranial Reconstruction using Double Side Incremental Forming demonstrates that it is possible to produce a cranial plate using Grade 1 pure titanium.
The paper concludes that [DSIF] could produce the cranial plates without using a backing plate, which [suggests] considerable benefits in the application of cranial reconstruction compared to variants of ISF which use a backing plate or supporting die (which reduces the process flexibility and increases the cost).