Laser Interferometer Alignment Fixture

Instron | Advanced Video Extensometer | Fixtures

Overview

I designed an alignment fixture that introduced additional degrees of freedom to a laser setup used in verification and validation testing. This fixture significantly reduced setup time between testing configurations and made the process more accessible for users with minimal prior experience.

 

Solutions

  • Improved Alignment: Added degrees of freedom to enhance laser fixture precision, increasing viable test space.

  • User-Friendly Setup: Simplified alignment, making the system accessible to non-experts.

  • Damage Prevention: Reduced risk of optic damage with refined alignment methods.

  • Cost-Effective Design: Utilized 3D printing and existing hardware for an efficient solution.

Challenges

  • Misalignment of laser optics affecting measurement accuracy.

  • Risk of optic damage due to existing alignment methods.

  • Complex setup process, requiring expertise to operate.

 

Design & Development

Concept Generation ❖ CAD ❖ Prototyping

Manufacturing

Material Selection

Communication

Cross-Functional Collaboration ❖ Documentation

Improved Alignment

The Renishaw laser interferometer relies on top and bottom optic fixtures to precisely measure separation distance, a critical parameter in tensile displacement verification. Due to the large displacement range of the Instron machine, even slight angular misalignment could disrupt laser tracking. The alignment fixture eliminated this issue by enabling precise adjustments, ensuring continuous and accurate readings from the Renishaw software.

 

Easy to use

During a recent V&V cycle, we onboarded two new team members to support performance verification of our advanced video extensometer. With 32 setup changes required, the Renishaw laser interferometer needed to be repeatedly assembled and aligned. Using the fixture, we reduced total alignment time from 32 hours to just 2.7 hours—a 92% improvement. This efficiency allowed the team to ramp up quickly and stay on track for the review gate and product launch.

 

Minimal Downtime

I leveraged available spare components and 3D-printed a functional solution using Markforged Onyx—chosen for its high stiffness and suitability for the application. This approach was not only cost-effective but also faster than outsourcing to a machining service. It also enabled quick iteration and easy feature additions for future needs.

 

Final Product

Impact:

  • Significant Time Savings: Reduced laser setup time from 32 hours to 2.7 hours (92% reduction).

  • Expanded Testing Capability: Removed limitations caused by poor laser signal alignment, allowing for a larger usable test area.

  • Cost Efficiency: Minimized risk of damaging a $3.5K optic with a simple, $9 solution.