Machinedesign 1812 Umbra Cuscinetti803 0 0

Steel and ceramics give ballscrews a boost

Aug. 1, 2003
Ballscrews in electromechanical injection molding machines have a hard life operating in a high-pressure, unforgiving, and often neglected environment

Ballscrews in electromechanical injection molding machines have a hard life operating in a high-pressure, unforgiving, and often neglected environment. Despite working under high loads, they are expected to last a long time. Umbra Cuscinetti, part of the Italian conglomerate Umbra Group, is making significant strides in tackling issues of its ballscrews’ longevity and repeatability in poorly lubricated molding applications thanks to a concept using Cerbec silicon nitride balls from Saint-Gobain Advanced Ceramics, East Granby, Conn.

“We use larger ceramic balls spaced by smaller steel balls,” explains Luciano Pizzoni, stress analyst and R&D chief engineer at Umbra. “With this design, the rigidity of the system can be optimized and wear is no longer an issue. Components with ceramic balls are very forgiving. Using both ceramic and steel balls, which resist adhesion, provides high-load capacity, reliability, and an increase in the number of cycles.”

According to Umbra, ballscrews with Cerbec components can handle loads to 1,800 kN, have axial speeds between 150 and 160 m/min, and offer acceleration in the range of 3 gs.

In addition to high-load considerations, says Pizzoni, systems using Umbra ballscrews are designed for applications where little lubrication is present.

Flying the ‘Wright’ way

In 1903, the Wright Flyer became the first powered, heavier-thanair machine to achieve controlled, sustained flight with a pilot aboard. To mark the centennial anniversary of Orville and Wilbur Wright’s maiden flight, the Wright Redux Association, a Glen Ellyn, Ill.-based group, assumed the goal of constructing an exact functional replica of the Wright brothers’ plane. The group plans to fly the replica, dubbed The Spirit of Glen Ellyn, on the front lawn of the Museum of Science and Industry Dec. 17, exactly 100 years after the Wrights’ famous flight.

Bison Gear and Engineering has been a key partner in the project, volunteering its St. Charles, Ill., facilities and gearmotor expertise, as well as the design and manufacture of the gearing, ignition system, and magnets crucial for the engine’s functioning. Despite vague sketches and records by the Wright brothers, Bison’s “gearing solution proved to be correct, and The Spirit of Glen Ellyn performed remarkably well,” says Ted Craft, Wright Redux co-president.

Three other groups are undertaking the challenge of building a Wright Flyer replica — Smithsonian Institute, NASA, and Experimental Aircraft Association. Despite the tough competition, Bison and the Wright Redux Association was the first group to get its craft airborne in an April test flight.

Robotic road warriors

The war in Iraq provided a glimpse into the future of combat, one in which unmanned systems play a much bigger role. Considering the potential robotics technology has in protecting the men and women who defend our nation, the U.S. Dept. of Defense is stepping up efforts to develop autonomous robotic ground vehicles.

As part of the endeavor, the Defense Advanced Research Projects Agency (DARPA), the DoD’s central research and development agency, is conducting the DARPA Grand Challenge, a race of autonomous robotic vehicles from Los Angeles to Las Vegas. Scheduled for Mar. 13, 2004, the Grand Challenge will cover a course of approximately 250 miles, a rugged combination of off- and on-road terrain that will be cleared of interfering vehicles. The team that most quickly completes the route will receive a cash prize of $100 million.

Entries must be unmanned ground vehicles capable of completing the entire course without external communication or human control. The exact route will not be announced until two hours before the start of the Grand Challenge. All vehicles are required to have emergency stop capability, and they must undergo a safety inspection the day before the event.

For rules and other information, visit

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Crash course on noisy gears

If you’re involved in the analysis or manufacture of simple and complex gear systems, check out these short courses offered by Ohio State University in Columbus. The basic course runs Sept. 10 to 12, and an advanced class is held Sept. 15 to 16.

The purpose of the courses is to gain a better understanding of gear noise generation, the methods of measuring and predicting gear noise, and the techniques used for reducing gear noise and vibration. The basic course covers the fundamentals of gearing, noise, analysis, and measurements through a combination of demonstrations and lectures. The advanced session is for individuals who have attended the basic class. It will be taught through lectures on selected topics, coupled with a series of hands-on workshops.

Visit for more information.

Pack Expo goes international

Attendees to Pack Expo Las Vegas will get a taste of Latin American packaging with the addition of three international associations: Argentine Packaging Institute, Brazilian Packaging Association, and Mexican Packaging Association.

These leading associations will feature award-winning packages within the Showcase of Packaging Innovations, a feature of Pack Expo Las Vegas Containers and Materials Pavilion. The three associations will join eight other organizations presenting innovative container ideas.

Pack Expo Las Vegas, produced and sponsored by PMMI, takes place Oct. 13 to 15 at the Las Vegas Convention Center.

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