Compressive Glass Test
Determining the Strength of Glass by Flexure
Overview
Key Challenges
4 Day time constraint
Completed during onboarding
Fixing components during tests
My Role
Mechanical Engineer - Team of 1
Synapse Product Development
San Francisco, CA
Skills Applied
CAD Modeling (SolidWorks)
In-House Fabrication
Brainstorming
Design Review
Year
January 2020
About
This test fixture was constructed to characterize the material strength of a manufacturing lot of tempered glass. The testing took place at an external testing facility. The fixture needed to be compatible with a compressor machine and intuitive for test engineers to use repeatably.
Synapse's client used the test results to inform their decision on a material for their developing product.
System Overview
Requirements
1. Test 25 12"x18"x1/4" tempered glass panels
2. Test panels in compression until brittle failure is achieved
3. Maximum force at failure recorded for each sample
4. Vertically supports samples at 4 points in a rectangle
5. Captures glass fragments
6. Repeatable at a testing facility
7. Sits flat on compressor tester
Brainstorming
My design process began with leading a brainstorm with the mechanical engineering team at Synapse. I explained the requirements and gave everyone time to sketch ideas on post-it notes. After everyone presented their concepts, I chose the best features and began to create a final design.
Component Selection
The brainstorm helped me separate the test fixture into 4 major components that each had its own set of requirements:
1. Force Applicator
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100mm diameter
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Rigid material (6061 Aluminum)
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Radiused edges
2. Vertically Elevated Supports
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4 points in a rectangle
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Repeatable placement
3. Base
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Keeps supports in place
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Sits flat on compressor
4. Shard Catchment
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Captures glass fragments
From here I was able to research parts on Mcmaster and make some rough sketches.
Design Review
After creating CAD models, I held a design review with the manager at the facility where we were going to test. The purpose was to ensure that the fixture would be compatible with the compressor tester and that it was intuitive for the employees at the facility to use. The design was approved.
Testing Day
We brought the completed fixture to a testing facility that had a compressor. 25 panels of glass were tested to failure to characterize the material strength of a manufacturing lot of tempered glass.
Conclusion
Testing was a success. We were able to provide meaningful data to a client that was considering using glass for their new product.
I designed, fabricated, and tested the fixture all within 4 days during my second week at Synapse. However, the glass testing did not stop here. I was tasked with creating a test fixture that could meet ASTM testing standards.
I had 4 weeks to create a more refined fixture. Follow the link below to view the ASTM-C158 test fixture.
Slow Motion Shattering
(Lower Volume)