HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  RESOURCE CENTER  |  INDUSTRIES
Blogs
Sherlock Ohms

# Inaccurate Measurements Skew Data

NO RATINGS
Page 1/2  >  >>
User Rank
Blogger
How long it is really?
7/26/2012 11:53:04 AM
NO RATINGS
This Sherlock Ohms posting is a great example of the danger of assuming. He asked for 10 feet of cable, he was given a length of cable. But he didn't check to make sure he actually received 10 feet of cable.

User Rank
Platinum
Re: How long it is really?
7/26/2012 12:17:02 PM
NO RATINGS
This is good evaluation of the method and the actual test. As a manufacturer, there are times that I have doubted the test when the result is not what you expect.

User Rank
Platinum
Re: How long it is really?
7/26/2012 2:09:10 PM
NO RATINGS
The real problem is that we rarely double check when we get the data we expect.

User Rank
Platinum
Re: How long it is really?
7/26/2012 9:06:53 PM
NO RATINGS
Trust, but Verify. This example belongs in a collection of wise tales and parables handed to each new measurement apprentice. When it comes to measurements, folks should not be offended when their data is double-checked but instead remind the receiver to re-check their measurements and calculations. Imagine how much unnecessary effort and research was avoided by checking the initial value...

User Rank
Blogger
Re: How long it is really?
7/27/2012 12:24:00 AM
NO RATINGS
I couldn't agree more, William. Yet I can certainly see how this happens. It takes conscious vigilance to avoid this kind of problem.

User Rank
Platinum
HOW LONG IS IT
7/27/2012 5:31:54 PM
NO RATINGS
I'm not too sure how you get around this one.  One company I consult for has work instructions AND a check list AND employee training AND there are still errors made relative to measurements.  I will say this, we use a software package called MiniTab to perform Six Sigma calculations.  With this software package, it is fairly easy to discover measurement errors.  We always try to run a sample size of at least 30 pieces PER shift.  Sometimes when we are checking against critical-to-quality specifications, we collect samples every hour for analysis. Another important factor, we always measure and calculate for gage R&R and factor that into analyzing the final data.

User Rank
Blogger
Measure twice, cut once
7/30/2012 12:53:30 PM
NO RATINGS
Many years ago a VP of engineering I knew had a sign on his office wall: "Measure twice, cut once." I memorized that one, and it's been helpful for avoiding mistakes like this one. Of course, it's easier to observe this rule when it's just you doing the measuring both times. I like the "Trust, but verify" maxim. That maxim completes the first one.

User Rank
Platinum
Re: How long it is really?
7/30/2012 10:25:28 PM
NO RATINGS
Some manufacturers do not always see that it is better to reject a good part than pass a bad one.

User Rank
Platinum
inaccurate measurements and screwed-up data
8/2/2012 9:52:53 PM
NO RATINGS
The problem came from assuming that the directions had been accurately followed. I had a similar problem when a new tech grabbed a stack of incomplete circuit boards from a stack and then was challenging me that my design was no good because the boards didn't work. I wound up posting a general memo that "designs will not perform as required unless they are built as designed." The lab manager challenged me as to what it was about, and I explained to him that it meant that the circuit boards would not work correctly unless all of the parts were installed. He agreed that was a correct assertion, and cautioned that tech to only use circuit boards that had passed the final inspection. The non-calibrated boards seldom met the requirements, and the incomplete boards never met them.

User Rank
Platinum
Re: inaccurate measurements and screwed-up data
8/9/2012 4:56:04 PM
NO RATINGS
William: Your story really touches a raw nerve with me. I have lost count of how many times the "New Guy" finds errors where none exist merely because he wanted to impress somebody higher up with just how much he knows. Not all new guys, but a significant number.

Page 1/2  >  >>
 Partner Zone
More Blogs from Sherlock Ohms
If the fuse and fuse holder don't match up right, hefty repair bills might follow.
The light amid darkness increased suspicions. A secret power source was the answer.
At the battery factory, a number of things can go wrong, from lousy suppliers to oddball crimping.
The recording device failed when it heard a loud, screeching voice.
The radio station couldn't keep its clock synchronized. Apparently, the power company was goofing up the time.
Design News Webinar Series
5/22/2013 9:00 a.m. California / 12:00 p.m. New York / 5:00 p.m. London
5/15/2013 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
5/29/2013 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
5/30/2013 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
From Dell / Intel®
Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013    3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
Most recent post: Scott Hamilton
From Dell / Intel®
Trey Morton, Dell, 4/25/2013    2
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
Most recent post: honur
From Dell / Intel®
Kirsten Billhardt, Manufacturing Industry Marketing Strategist, Dell, 3/26/2013    5
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
Most recent post: notarboca
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
May 20 - 24, Automation Technologies & Trends for Smarter Homes & Buildings
SEMESTERS: 1  |  2  |  3