Where Are You on Taniguchi’s Chart?

Last year, on the occasion of Mori Seiki’s 60th anniversary, Dr. Masahiko Mori commissioned a book that speaks to the importance of machine tool technology to the quality of life in our world today. It is called the Path of
Precision and was written by David Dornfield.

In chapter one, Mr. Dornfield lays out the foundations of precision manufacturing with a focus on the trend towards better, more complicated products and the miniaturization of many of those products. Of course, smaller, more complex products demand smaller and more complex discrete parts to be machined. This trend leads to a discussion of the Taniguchi chart, which I had never heard of.

In explaining the Taniguchi chart, Mr. Dornfield calls it the mechanical complement to "Moore’s Law." Most of us are familiar with Moore’s Law, formulated in 1965 by Gordon Moore, co-founder of Intel, which predicts that the number of transistors that can be placed on an integrated circuit will double approximately every two years. So far that prediction has held true and resulted in the amazing array of small, powerful electronic devices so ubiquitous in our everyday lives.

Starting in 1983, Japanese researcher Norio Taniguchi is credited with defining many of the terms we use to discuss micro-scale manufacturing. In 1983, micro-machining was as sci-fi as nanotechnology seems today. We’ve learned how to make increasingly small components applying micro-machining technology to shape the parts those products require. As an industry, we’re now at a point that in 2009 micro-machining is a capability offered by more and more machine shops. My guess, and Mr. Taniguchi’s prediction, is we’ll see similar progress into nanotechnology in 20 years.

The Taniguchi chart looks at the development of achievable machining accuracy over time. It plots "normal" machining, "precision" machining and "ultra" precision machining on an accuracy scale from 100 microns to a mind bogglingly small 0.0003 micron.

Normal machining includes what you’d think—CNC machine tools, lathes, mills, grinders, lappers and hones. According to the chart, at the rate these machines have improved in accuracy, they will be capable of 0.1-micron accuracy by the year 2020.

As for precision machines, these include jig bores, jig grinders, diamond lathes and grinders and super finishing machines. By the year 2020, based on historic accuracy improvements, Taniguchi predicts these types of machine tools will be capable of accuracy just shy of 0.001 micron.

The ultra precision machining category lists super high precision grinders, lappers, polishers and some NASA-sounding processes listed as atom, molecule or ion beam machining and atomic or molecular deposition. In 2020 an accuracy of 0.0003 micron will be possible. To get an idea of how very small this is, a virus measures about 1.2 microns.

Looking at the chart plots today, normal machining comes in at a little better than 1 micron accuracy. Precision machining comes in currently at 0.01 micron capability. And ultra precision machining can produce accuracies a little better than 0.001 micron in 2009. Machining has a way to go to hit Taniguchi’s predictions, but Moore’s Law has been pronounced dead more than once. I think Yogi Berra said it best: "It’s tough to make predictions, especially about the future."

I would take a bet that your shop is holding tighter tolerances today than it could in 1983. Probably, you are better today than you were in 2000. It’s just a natural progression for manufacturing tools and techniques to improve in response to its customers’ needs and demands.

So the question is, where are you now and where will you be on the Taniguchi chart?