Rick Hudgell’s default image

By: Rick Hudgell

As industry standards increase, so too does the demand for flexibility in specialized gaging procedures. Because there’s no room for error, choosing the right contact point or styli is paramount in conforming to the organization’s high quality standards. Accuracy can be jeopardized by any number of variables, but the contact point shouldn’t be one of them.Styli are manufactured in a number of different designs, shaft materials and tips. Each contact styli is designed for special applications. As the initial contact component of the measuring process, sphericity and rigidity are critical when choosing styli.

When choosing replacement styli, a few important qualities must be remembered:

  • Keep the styli as short as possible to prevent bending or deflecting.
  • Use as large a ball or tip as possible.
  • Minimize the use of joints or extensions. Custom-made styli are better choices.

The point of contact is the most critical aspect of accurate gaging. Therefore, careful consideration must be given to the probe tip and the ball material:

 Ruby-tipped probes

Michael Metzger and Jim O'Brien’s default image

By: Michael Metzger and Jim O'Brien

Many customers come to Hobson & Motzer seeking a solution for what others have claimed is impossible. Established in 1912 and based in Durham, Connecticut, Hobson & Motzer engineers manufacturing processes and designs tooling to produce seemingly impossible parts for companies worldwide.Hobson & Motzer is often selected for projects other companies aren’t able to accomplish. That’s why Hobson & Motzer people are called “quality critical” craftsmen. They see every part as critical and bring a can-do attitude to every job.

Today, manufacturers are turning out parts with smaller and more precise features than ever before. To improve productivity, traditional methods of inspection must evolve to improve accuracy, optical capability and statistical analysis, while communicating huge amounts of high-resolution information to quality inspectors. Hobson & Motzer took this giant leap from manual to automated inspection.

Keith Bennett and Howard Zion’s default image

By: Keith Bennett and Howard Zion

Test and measurement equipment (T&ME) must be periodically calibrated to ensure it’s operating within its specified parameters. Of course, the uncertainty of the system used to calibrate the equipment shouldn’t add appreciable error to this process.Test and measurement equipment (T&ME) must be periodically calibrated to ensure it’s operating within its specified parameters. And, of course, the uncertainty of the system used to calibrate the equipment shouldn’t add appreciable error to this processThe calibration process usually involves comparison of the T&ME to a standard that has similar functions with better accuracies. The comparison between the accuracy of the unit under test (UUT) and the accuracy of the standard is known as test accuracy ratio (TAR). However, this ratio doesn’t consider other potential sources of error in the calibration process.

Quality Digest’s picture

By: Quality Digest

Shortwave infrared (SWIR) imaging is quietly earning a growing place in industrial machine vision for quality inspection. SWIR imagers, sometimes also referred to as NIR imagers, can see objects and events that vision and thermal cameras cannot. Moreover, they’re’ smaller and lighter than all thermal cameras, and cost far less than many of them (See table below). Furthermore, most indium gallium arsenide (InGaAs) SWIR cameras are all solid state, with no shutters, cooling systems or other moving parts. Some come factory set, with no need for user nonuniformity corrections throughout their entire service lives. All SWIR imagers work with plain glass optics, avoiding the thermal camera requirement for silicon or germanium lenses, which can cost 10 times as much. The installed base for InGaAs SWIR detection is steadily rising in both military surveillance and industrial imaging primary due to the low noise and simple operation of these cameras and arrays. These devices permit detection in the SWIR band with minimal cooling and electronic overhead, making the cameras similar in operation to silicon CCDs and CMOS imagers. With the increasing use of InGaAs cameras, people’s confidence in using these cameras 24/7.

Gary Card’s default image

By: Gary Card

How many dimensional data points are enough to accurately describe a part feature? The key to answering this question is understanding the stability of the manufacturing process. In general, components should be measured only as often as required to ensure the stability of manufacturing processes. This requires identifying and monitoring part features that are critical to the part’s end-use function and developing a strategy to control the dimensions of those features.

The choice of manufacturing technique is the key factor in choosing a process control method. If, for example, the manufacturing process reliably produces a critical bore with good form, its size or position may vary. In this case, control of the size and position will be important but not necessarily roundness or cylindricity control. By contrast, if the machining process produces features with significant form variation (i.e., the variability of the form is a significant proportion of the form tolerance), then understanding where and how the form errors occur becomes important.

Some features may need to mate with other parts for the end-use product to work correctly. In many cases, the form or profile of these features is critical to the functional fit; consequently, the processes used to make these features must be precisely controlled.

Gary Card’s default image

By: Gary Card

Coordinate measuring machines gather data by means of a probe or sensor. Conventional CMMs equipped with touch-trigger probes can use a stitch-scanning method to record point streams from part surfaces. In stitch scanning, the CMM lifts the probe head from the surface of the part, moves it slightly forward and lowers it until contact is made for every data point collected. This single-point procedure is slow and unsuitable for efficient form measurement. Analog probes for continuous scanning are designed to send an uninterrupted stream of data back to a system computer. These probes avoid the time-wasting auxiliary movements required by point-to-point measuring probes.

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