Table 1. Requisite Closure Pressures.
| Parameter Design Variations (all other parameters are held constant according to the standard design) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Membrane Thickness | Channel Width | Membrane Material Stiffness | |||||||||
| 200 μm | 300 μm a | 400 μm | 500 μm | 700 μm | 900 μm | 1100 μm | 1300 μm | Shore 26–28 Scale Aa | Shore 35–40 Scale A | Shore 57–63 Scale A | |
| Control Pressure for Valve Closure (defined as ≤ 3.5 μL/s full flow) (psi) | 15.0 | 28.8 | 36.3 | 42.5 | 30.0 | 26.3 | 25.0 | 22.5 | 28.8 | 35.0 | >73.0b |
Control pressure required for valve closure experimentally found for design variations. Listed stiffness values for the membrane material are sourced from Stratasys, Ltd material data sheets [24]. Closing pressures varied between different samples or different runs. The value represents the average control pressure at which the valve was closed (defined by a flow rate ≤ 3.5 uL/s) for all trials and printed valves. Error of ± 4.4 psi was found between trials of the same printed valve.
a Same sample data
b Valve did not close at control pressures tested. Flow measured at 73.4 psi was ~49% total flow and a single trial was conducted for this file.