Instron Grip Re-design

I was tasked with improving the strength, power efficiency, and measurement accuracy, of the grips as well as reducing the potential for user error.

• Examine how the product has failed in the field and hypothesize reasons for the failure (is there user error or a design flaw or both?)
• Analyze existing design to see where there may be inefficiencies
• Observe what is happening with the grip during testing that may be impacting results
• Brainstorm and sketch out designs to improve flaws
• 3D model and print best design ideas
• Test prototypes and improve models (repeat as much as necessary)
• Create drawings for finalized design
• Order new parts and test, make changes if necessary

• Look at where parts have broken in the field and analyze using FEA
• Create an assembly of the grip to simulate the movement of parts and see where energy may be lost to friction
• Analyze how data error can be reduced with pre-loading samples
• Re-model components from scratch taking into account the knowledge and intent from prior analysis
• Insert prototypes into SOLIDWORKS assembly, making necessary changes
• Print prototypes and install them into a grip to ensure functionality
• Finalize design, creating drawings for machining and order parts
• Test prototypes against originals and compare

• It was difficult to re-design the parts to improve the geometry while still fitting withing the existing frame
  • It was decided that the frame would need to be changed, as there were existing issues with the frame already
• Thoroughly testing the 3D printed prototypes was impossible because they would break under actual test conditions
  • Machined metal parts had to be ordered to perform rigorous testing
• Getting funds for real machined parts was difficult
  • It had to be proved that the design changes would produce significant beneficial results for the customer
• It took a long time for the prototypes to be manufactured
  • The parts had to be tested after my co-op was over

• The FEA of the prototypes showed that they were significantly stronger than the previous design and that they would hold up over long term testing under forces more than 20% greater than the max force that the grips could apply
• The 'slipping' in the inner mechanism was almost entirely reduced, greatly decreasing the internal friction and 'jolting' motion between parts
• By reducing 'jolting' and improving the effectiveness of the pre-loading geometry, measurement accuracy was improved
• As of right now, testing has shown great improvements in testing results under most grip positions but only some improvement in other positions. Further testing and analysis is required