Precitech Shapes its Lathes with QNX

Precitech, Inc. is an ultra-precision machine and metrology systems manufacturer incorporated in the United States and located in Keene, New Hampshire. The company provides a complete line of ultra-precision single-point and multi-axis diamond turning, grinding, grooving, and milling machines for the production of components by the electro-optic, ophthalmic, and precision metal-working industries.

Precitech began operations in 1986, and has the largest industrial base of installed ultra-precision machining systems in the world. With over 600 ultra-precision machines operating today on five continents and in most industrialized nations, Precitech has placed machining systems in many government and research laboratories both in the United States and abroad.

Making the switch from hardware to software motion control

Precitech's customers demand highly reliable tools because what they manufacture is not only expensive, but must be incredibly fine-tuned. Some manufacturers build mechanical components that require tight dimensional and finish tolerances (submicron grinding and hard turning), while others produce contact lenses, lens molds, intraocular lenses, and other specialized vision devices. If Precitech wants to keep its customers exceedingly happy, its ultra-precision tools must be ultra-reliable.

Through the mid-1990s, Precitech relied on commercial motion-control hardware to regulate its lathes. But, to stay ahead of the competition, the company needed to push the limits of its tools further than what the hardware allowed. A decision was made to operate the machine controller entirely in software since the "price to performance" ratio of computer software was improving. Some of the competition touted Microsoft Windows as a "realtime" operating system (RTOS), but technically that fell far short of hard realtime specs. Precitech knew that users would not and could not tolerate a machine that might lock up, perhaps destroying a multi-thousand-dollar component. Another option was to consider Windows as a wrapper around a motion control card. This, however, did not solve the original bottleneck - the motion-control card itself.

In 1996, Precitech began investigating operating systems for its next-generation products. After a lengthy process of reviewing vendors and testing RTOSs, Precitech selected the QNX® RTOS because of its hard determinism, stability, and superior fault tolerance. According to David Davis, president & CEO, "the microkernel architecture allowed us to create a fast, deterministic system that exceeded our requirements." The project started in earnest in December 2000.

Seamless transition to QNX

"The development experience was as pleasant as the learning experience," said Walter Lewandowski, R&D manager. "Documentation, online help, and access to a web-based developers forum allowed us to rapidly exploit the power for which we had originally chosen QNX. It took only 10 months to go from my first serious tinkering with the RTOS to having a functioning system - the development process was much faster than I had expected."

With reliability and modularity comes the ability to innovate

Today, all of Precitech's software is developed using the QNX RTOS and QNX's high-performance graphical interface, the Photon microGUI®. By having total control over its control/servo system (lens cutting tools), Precitech can now ultimately achieve superior part cutting results. No longer hindered by having to make firmware changes, Precitech can now create and test scenarios in a matter of minutes. This means that an end user's product can benefit from a custom control system, designed expressly for it.

With QNX, Precitech no longer has to use the "one size fits all" control system and rely on creating nice-looking bells and whistles to achieve an apparent technical edge. "Form and finish is what our business is all about," says Davis. "We now have complete control over form and finish and can provide the graphical interface and tools the world has come to rely on and expect."