Grinding Journal - Summer 2007 - (Page 8)

How does testing work? How does a full-service testing company like Dirats (pronounced dihr-ats) Laboratories work? In a typical sequence, a customer sends a high value part with a request for data about that part. For example, does the material meet a certain standard for high cycle fatigue? Or high-temperature tensile strength? Or any number of other properties. Dirats Laboratories creates a test specimen from that part, conducts the necessary tests on that specimen, and issues a certified report. That’s the simple version. Let’s explore some of the challenges. “Old timers” who took the tough courses in college Dirats Laboratories stands out for the breadth of the testing they can perform. Not just mechanical testing, but also chemical and metallurgical analysis. They also handle the most difficult materials, which might mean using X-ray diffraction to characterize the phase composition of a ceramic coating powder. Or a plasma mass spectrometer to assess the trace element composition of an aerospace alloy. It’s real egg-head work. So perhaps it’s no surprise the average tenure of their testing professionals is an astonishing 18 years and growing. Why? Perhaps because Dirats Laboratories is a family-run business that has focused on testing from their foundation in 1939, nearly seventy years ago. Current president Eric Dirats (grandson of the founder) virtually grew up in the shop. Machining Supervisor Richard Irwin looks over a wide variety of parts and material samples awaiting testing. These “raw” samples require machining to create a testable specimen (note the markings on the part in the foreground). As the paperwork suggests, Dirats Laboratories tracks each part throughout the process of machining and testing. When it absolutely, positively has to be there overnight It’s an intensely service oriented business. In a typical example from airframe manufacturing, a customer might forge and heat-treat a fifteen foot long landing gear leg, including a “prolongation” that he cuts off and sends to Dirats Laboratories for analysis. But he’ll have to withhold the part from further manufacturing until Dirats Laboratories confirms that the prolongation passes the tests. So they will perform the testing overnight, even though the part is Rockwell 60 and even when they don’t know it’s coming until 4:00 in the afternoon. This helps explain why most Dirats Laboratories employees are in a Quality or Technical Support role, not machining or testing. (By the way, Eric Dirats tells us that “Every leg you see on a commercial airplane has had testing done on that specific piece of metal.” Like he says, that’s “nice to know!”) (pictured to the left) Turbine components are probably the most commonly tested item at Dirats Laboratories. Here Richard checks-in a just arrived forged blade. The markings indicate which sections need to be cut out and tested. Grinding Journal

Table of Contents Feed for the Digital Edition of Grinding Journal - Summer 2007

Contents My Thoughts Exactly When Lives Are at Stake Walter Consolidating Production The Art of Grinding: Knowing the Source of Grinding Errors and How to Fix Them The How and Why of Conventional Vitrified Grinding Wheel Selection Grinding Glass Flat Problem Solver

Grinding Journal - Summer 2007

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