“I am excited about returning home to work at Oak Ridge National Laboratory, building research and development capabilities in machining and machine tools,” Smith said. “I hope to add a powerful new dimension to the strong manufacturing expertise already in place at ORNL."...

“Tap-testing is a powerful technique that could provide significant cost savings compared with using conservative cutting parameters or trial-and-error tuning of cutting parameters” ...

Optimizing machining performance has helped innovative high precision engineering company Produmax double its turnover and the number of people it employs and laid the foundations for similar growth in the future. A combination of Ballbar and Tap testing enabled the company to optimize the physical performance of its machine tools...

If a history of “high speed machining” is ever written, it might include a moment in the late 1980s when Jerry Halley, of what was then McDonnell Douglas, heard from Ron Aarns that he was free to go ahead with the company’s development of HSM....The notion of using dramatically higher milling spindle speeds was not at all new when Mr. Halley turned to Dr. Scott Smith...

The advanced machining methods used by this shop deliver machining times that are two-three times quicker than previously possible for tough, complex aerospace components. With resonance measurement (tap-tests), accelerometers are fitted to the cutter. Readings are taken to establish the best cutting conditions and methods to maximize metal removal rates by taking much deeper cuts than would normally be possible, avoiding problems commonly found when cutting titanium, such as burning the tool and chatter that can damage the material and lead to high scrap rates.

Warner Robins contracted with the company BlueSwarf both to perform the tap-test analysis and to provide resources including the Tool Dashboard. BlueSwarf is a firm specializing in machine-tool vibration analysis. The company sells a “Metalmax” analysis kit for shops to perform this analysis internally, but the company also performs the analysis itself on-site, for shops that want to contract out this work...

AML’s raison d’etre is to take a part, however complex and establish the most productive and economical way of manufacturing it – from prototype through to full batch production. It achieves this via a number of scientific methods centered around machine dynamics optimization such as Tap Test Analysis​...

With resonance measurement, accelerometers are fitted to the cutter and, in some cases, the billet. Readings are then taken to establish the best cutting conditions and methods. Using this technology enables the company to maximise metal removal rates by taking much deeper cuts than would normally be possible, avoiding problems commonly found when cutting titanium such as burning the tool and chatter which can damage the material and lead to high scrap rates. Dr Gareth Morgan says, “Resonance technology was my field of study for my PhD, so we are well advanced in its use. For aerospace parts we are working with aggressive materials and we are frequently removing over 80% of them, so this is a very important technique for us​...

Dr. Tony Schmitz, a professor at the University of North Carolina at Charlotte, recorded this quick presentation on machine tool dynamics. It’s worth watching—less than 12 minutes long, with a quiz at the end to make sure you got the key points. If you understand that vibrations are a major contributor to the performance of your machining process, but don’t quite know how to put this understanding to practical use, then this presentation is where to begin...

Through vibration-analysis testing using the MetalMax system., Mr. Halley measured the frequency response characteristics for this machine to determine its ideal high-productivity spindle speeds for various standard tools in the shop. With this information, he determined new speeds, feed rates and depths of cut for programs to be run on the machine, but he didn’t have to change any tool paths. High speed machining tool paths that were already being run productively on the older machines could now be run even more productively on the new machine. The machine started making money for the shop almost as soon as it hit the floor

These plots feature “stability lobes” above which the combination of depth of cut and spindle speed results in unacceptable vibration. The key is to select the highest speed that falls under the last acceptable lobe to give the largest possible depth of cut...

Dynamic analysis in milling is one example. The technique of adjusting spindle speeds in milling to achieve high metal removal rates by quieting chatter has been known since the 1970s, yet very few machine shops are taking advantage of this possibility. Many more of them should take advantage of it, he says. He guesses there is 20 percent latent capacity just waiting to be achieved through methodology improvements on current suppliers’ existing CNC machines, even before any new capital investment is made.

The mic picks up the sound of the chatter, which is easy to hear through the closed doors of the machine, and the laptop records a sample as a data file. The software running on the laptop studies the sample and analyzes the vibrations detected in the data file. If chatter is present, the software then applies algorithms that determine what spindle rpm will fall within a stable speed range...