Finite Element Analysis is a dark art, easy to become lost in its wizardry and we have to take the numbers it generates with a grain of salt. FEA analysis is a great tool to understand the behavior of our designs under various loading scenarios to help us design cheap and easy parts. It will shine a spotlight on weak areas and reveal elusive obvious insights into a more efficient design.
Too often engineers and designers become excited and start generating FEA models without understanding how critical loading and model simplification is to the results. However, if one understands the fundamental science behind the analysis and check results with first order calculations to verify they are in the right ballpark, FEA can be a very powerful tool for even simple tasks.
Here is a prime example of a very simple fixture design I came up with for one of our favorite customer’s. The fixture is to house a PCB, that is machined to house a tiny optical mirror that is 3 x 3 mm; very tiny.
As always, I love opportunities to employ DFM and crafty means of eliminating unnecessary components to make things cheap and easy. This design employs just two socket head cap screws with the top and bottom pieces. The clamping of the PCB is all achieved through the natural deflection of the material itself.
FEA was used to tune the deflection force quickly. I first performed basic first order calculations for a starting point, then I was able to quickly increase the cross-sectional area to achieve the desired force.
Furthermore, the slots are sized for standard end mill diameters and guess what? On the first try, it worked brilliantly. A perfect example of simple, cheap and easy. How did I know what the desired force should be? That’s where 20 years of experience comes in. The mass of the tiny PCB was negligible and I was concerned about over clamping which would cause deflection. I figured a good target was 1.5 pounds.
I’m confident that my 27 year old engineer self would of tried to do this with some sort of metal spring, spring plunger, toggle clamp or other more complex and expensive approaches when it was completely unnecessary.
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- We’ve spent the big bucks for a complete FEA package to complement our 20 years of engineering experience to help us provide you with peace of mind.
- We can help you converge on better engineering and design choices.
- Material performance, stress, heat, deflection, bearing stresses, coating and more…all become a tough issue to solve at one point or another.
- We have professionally licensed engineers in the state of California for Mechanical Engineering. License # M31341.
- Push your design through stress, deflection, fatigue, thermal, impact and structural simulations to reduce iterations of your design.
