How to Measure Internal Void Volume in SolidWorks

In microfluidic prototyping, a subtle geometric misalignment—such as an offset through-hole or an incomplete blind via—can pass standard visual CAD inspections while completely severing an internal fluid path.

The result? Additional mold modification costs and, more critically, weeks of project delays. When devices are intricate and production schedules are tight, these manual oversights can easily slip past even experienced engineering teams.

A proven strategy to catch these issues before fabrication is straightforward: model the fluid path as a separate solid body in SOLIDWORKS.

This approach provides several key engineering advantages:

Verify flow-path continuity: Select any point along a channel network to instantly confirm whether the fluid region remains fully connected from inlet to outlet.

Calculate internal and dead volume: Measure fluid volume directly via Mass Properties without spreadsheets or hand estimates. For injection-molded components, this automatically accounts for draft angles, tapers, and corner fillets.

Accelerate design iterations: Identify bottlenecks, verify channel clearances, and adjust the design before committing capital to expensive tooling or physical prototypes.

Prepare for simulation: Export the standalone fluid geometry cleanly for computational fluid dynamics (CFD) and multiphysics modeling in platforms like COMSOL Multiphysics.

The best time to catch a design mistake is when it is still just a CAD model—not after the tooling invoice has been paid.

Watch the video above for a visual walkthrough on how to isolate and extract internal fluid volumes step-by-step.

Design Tip: Fully define all sketches in SOLIDWORKS. Constrained geometry prevents dimensions from shifting unexpectedly during design revisions, ensuring internal channels remain intact.