UL vibration test

[toyotaboy]

Looks like my work is making me pre-test our product with some sort of vibration test. At the very least, I have to buy equipment to measure it (harmonic distance and frequency), but it looks like if I want to buy a pre-made table I'm looking at $10-$15k. I'm considering building one myself, but I'm wondering if I'm going to have a difficult time building one (as far as getting the right rpm and weight offbalance on the motor).

 

[vpl]

my two cents: If you don't know what you're doing, then it will end up costing you about three times what it would just to go out and buy it ... Of course, the money will be spent in dribs and drabs and you won't realize the total cost until you get to the end of the project and take a look at how much time and money was spent. At which time, you will smack yourself on the forehead and say "I could have bought one for less than this."

Patricia Lougheed

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[toyotaboy]

thanks for the reply.. I'm going to need to buy the measuring equipment for $700 no matter what, so what I might do is build something with parts I have around here already to see how close I can get. I have a feeling (looking at a video of a UL certified machine running), that I'm going to need more than just a basic hobby motor. I have a feeling I'm going to need a big bulky AC servo motor at the very least.

Keep in mind, I don't think we're looking to be completely accurate as to perform a true test, I think we're looking to get an initial estimated test to see if our product can withstand it before we hand over $1k to UL to do an official test, who by the way only come around maybe once every 2 months to test our products.

 

[snoopnoon]

If your just looking for the modes or frequency response just perform and impact test with a force hammer and an accelerometer with supporting items such as: FFT analyzer, data acq. software.

 

[MikeHalloran]

Once upon a time, I tested a large and complex medical electronic machine by bolting a variable speed bin vibrator to it and ramping the vibrator speed. Recogize that because of the fixed stroke, the G levels go up with frequency. The DUT already had flexible rubber feet, so a table wouldn't have added much value. We didn't have the budget for a table anyway.

It was a very, very crude test, but it revealed a lot about our product. Screws started falling off of electrical connections within a minute.

We used a lot more Loctite after that.



Mike Halloran
Pembroke Pines, FL, USA