Metrology

This past week, I (Arthur) left my dear Alex in the heartland to venture to Niagara Falls, NY.  Friends and family have expressed much sympathy for Alex since she didn’t get to go, and I’d have to say their sympathy was well placed.  I would have loved to take Alex with me, but alas, business and pleasure on this particular occasion could not be made to mix.

The reason the Northeast called me from my beloved was for training on a machine we’ve been using at my company for about a year now, known as a CMM (I call it Pythagoras).  The reason I’m just now getting training on a machine I have been successfully operating for a year now is asked about as frequently as what a CMM is, and while timing for training, a delay here and a delay there is hard to explain, the latter question is a lot of fun.

A CMM is a $30,000 ruler.  It measures distances on components down to 0.0002” accuracy and distances you frankly couldn’t with your feeble handheld devices (imagine trying to eyeball the center of two holes within a thousandth on an inch.)  Furthermore, it’s programmable; if you do it right you should be able to set your part in place, hit go, and come back a half hour later to find a report listing hundreds of discrete measurements nicely formatted for you.

Many of our readers are perhaps still scratching their heads, wondering why in heaven’s name anyone would want to measure anything down to a thousandth of an inch, and why anyone would pay $30,000 for the privilege of doing so.  These readers might find the answer “So that your company sends you to Niagara Falls” about as satisfying an answer as can be provided.  The truth, however, is that as difficult as it is to imagine, gears pushing off other gears, a circuit board aligning well enough with its enclosure so it can be screwed into place, or a rod held in place with a bushing so perfectly fitted that they keep out water are all examples of applications where the difference of a fraction of the width of a human hair mean the difference between success and failure.

 

All of this delves grandly into a field that has slowly evolved into a burning interest for me: metrology.  Metrology is the science of measurement, a fact which, upon hearing, causes most people to add a new word atop their list of most boring subjects of which they’ve ever heard.  This is truly unfortunate thing; I would contend that metrology, along with pure mathematics and statistics, comprise the foundation of all good science.  After all, how can you test scientific hypothesis if you cannot with a high degree of certainty and accuracy, measure natural phenomena?  

 If you’d like to see how some of the most difficult problems in metrology are handled, check out the video below:

In other news on the trip, I did indeed go to the falls, and they were magnificent.   Perhaps I'll expand on that subject in a later post, but for now, I think I better end this post in keeping with the given subject.  Thanks for reading, and remember, Omnia vincit amore.