Metrology Features

Fred Mason's picture
Fred Mason
It’s becoming common to refer to the devices used for dimensional and coordinate measurement—vision/optics, lasers, touch probes, and others—as sensors. Multisensor measuring systems use two or more...
William Tandler's picture
William Tandler
What’s a datum reference frame? As discussed in workshop No. 5, datum reference frames (DRF) are coordinate systems, and preferably—at least to start with—Cartesian coordinate systems. As we know...
Anonymous's picture
How much is a kilogram? It turns out that nobody can say for sure, at least not in a way that won’t change ever so slightly over time. The official kilogram—a cylinder cast 118 years ago from...
Fred Mason's picture
Fred Mason
In dimensional measurement it isn’t unusual to measure feature locations relative to reference edges. How one measures an edge depends on how we define it. So what exactly is an edge? Basic edges...
William Tandler's picture
William Tandler
As we know, GD&T is a symbolic language with which to specify permissible limits of imperfection in manufactured parts, namely limits that maximize the parts’ operability, assemblability, and...
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Anne Willimann
The Airbus A380 is the most modern, spacious, and capable civilian aircraft ever. The project was launched in December 2000, christened “The Flagship of the 21st Century,” and developed in close...
Fred Mason's picture
Fred Mason
Happy New Year! One resolution many people have made is to cut costs. One way to do that is to manufacture in China. Just transfer your current manufacturing processes, use China’s lower-...
William Tandler's picture
William Tandler
Back in the 1940, when Stanley Parker, Mr. GD&T, decided it was time to create a set of tolerancing tools that realistically dealt with reality, two objectives were near the top of his list....
Fred Mason's picture
Fred Mason
During this annual holiday shopping melee, economists project the implications of our spending for the country’s overall economic health in the coming year. That can be like claiming a warm...
William Tandler's picture
William Tandler
Our original plan for workshop No. 3 was to discuss what are generally referred to as material condition modifiers, namely the encircled letters “M,” “L,” and “S” which sometimes follow tolerance...
Fred Mason's picture
Fred Mason
You manufacture a part that must be within design tolerances to work properly, so you need to measure it. It costs to: Buy the measuring device Provide a space and/or utilities for it Develop...
William Tandler's picture
William Tandler
Continuing with our analysis of the Greatest Design Tool ever, our objective in this article is to take a detailed look at the structure and contents of feature control frames to demonstrate that...
Fred Mason's picture
Fred Mason
Many measurements assume that a measuring device performs in the same way throughout its measuring range. In other words, a 1 mm distance measured near the center of a machine will measure 1 mm at...
William Tandler's picture
William Tandler
What is GD&T, anyway? The Greatest Design Tool ever, or a whole bunch of Gol-Derned Trouble? Actually, geometric dimensioning and tolerancing is both, and worth every penny. Only with the...
Fred Mason's picture
Fred Mason
All this talk about work in past columns—and the end of summer looming—makes me think about golf. You may not discuss golf and measurement in the same breath, but there are a lot of critical...
Fred Mason's picture
Fred Mason
In last month’s column, I talked about the accuracy funnel, which shows that in a measurement system where the sensor or the part is moved in one or more axes, the greater the distance, the...
Fred Mason's picture
Fred Mason
In last month’s column, I talked about the format of accuracy specifications for video measuring machines. The following is a typical format for a single axis accuracy specification: Ex =...
Fred Mason's picture
Fred Mason
Accuracy, repeatability, performance—knowing how to interpret specifications for measuring devices and systems is important. This month I’ll talk about accuracy specifications for...
Fred Mason's picture
Fred Mason
The past few columns about inspection and measurement have led to discussion of different systems for measuring based on images. One type of measurement done via image analysis is...
Richard Curtis Ph.D.'s picture
Richard Curtis Ph.D.
The speed, convenience and cost benefits of microliter volume, air displacement pipettes drive the frequent use of these precision instruments. However, pipettes, like all mechanical instruments,...