Case Study
Wearable Pump Capability Study
Challenge
- Client was unsure of robustness and fundamental viability of novel wearable pump concept
- Some initial prototyping and testing yielded mixed results
- The anticipated multiple cycles of prototype / test / iterate needed to establish viability would be expensive and many relevant test configurations – e.g., extremes of tubing dimensions – were inaccessible
KDPD Approach
- Created an analytical model for existing pump architecture
- Verified and supplemented analytical model with low level testing on device subsystems and components
- Performed Monte Carlo simulations and capability studies on several key metrics of the pump to assess capability at scale
- To evaluate the robustness of the design we used the capability index Cpk (commonly applied in component manufacturing) at the system level
We considered the 4-sigma, 99.35% yield, case where Cpk must be greater than 1.33.
Results
| Metric | Cpk | Meets with Margin | Does not meet |
|---|---|---|---|
|
Pumping Force |
12.2 |
X |
|
|
Delivery Accuracy |
0.56 |
|
X |
|
Delivery Rate |
-0.79 |
|
X |
|
Battery Life |
-2.27 |
|
X |
The results showed that this pumping architecture had fundamental shortcomings in several key metrics and is very likely not viable
Key Takeaways
- Analytical model and low-level testing approach allowed FPrin to identify that the design in question was not viable
- Identified technology as dead end quickly and at modest cost
- Saved client prototyping and testing time and money
- Resulted in FPrin conceiving of a “Plan B” – an alternative pump architecture that moved these key metrics to meet requirements
