A new tin dipping machine from Design & Assembly Concepts Inc. shows off some of the advantages of prototyping robots and machinery in National Instruments Corp.'s LabView software. And to National Instruments, prototyping is only the beginning.

The machine is a multiaxis robot. It retrieves a variety of different-style connectors from a fixture, dips them in solder flux and then solder, and returns them to the fixture. The operation requires tight tolerances, since applying too much solder causes uneven melting and poor connections on high-speed assembly lines.

LabView's new state chart capabilities make it easier to model robot and machinery behavior and run the models on digital control hardware.

Design & Assembly Concepts, based in Leander, Texas, developed the machine's control logic in LabView, a software package originally designed for building "virtual instruments" from sensors attached to PCs. In recent years, National Instruments has redesigned LabView to also handle industrial tasks.

Design & Assembly Concepts, for example, used LabView to model the tinning machine's operation. It then linked the control model to a CAD model using SolidWorks Corp.'s CosmosMotion to simulate the mass and physics of the 3-D objects. The resulting model showed exactly how the machine worked, right down to the speed, stiffness, and precision of the dipping arm.

"The conventional way of doing this was to have your mechanical and control engineers build their separate systems, and then test it on a prototype machine," said Design & Assembly Concepts' president, Ricardo Gomez. "Now, we can simulate both at once and see if parts jam or if we meet cycle time goals. And we can share the simulation with our partners, so they know exactly what they are getting."

The tinning machine currently runs on a conventional programmable logic controller. Eventually, though, Gomez would like to run his control model on one of National Instruments' digital controllers, which could run it without any changes.

This sounds like music to the ears of National Instruments' product manager, Todd Dobberstein, who is trying to position National Instruments as an automation solutions provider. He has an uphill battle. Not only must he overcome LabView's reputation as instrumentation software, but he must go up against such entrenched giants as ABB, Allen-Bradley, and Siemens.

Yet Dobberstein claims that LabView's roots in instrumentation are its strength: "We surveyed 30 machine builders worldwide, and 29 of them said their machines are getting drastically more complex while time to market is going down. The complexity is forcing them to use custom hardware, which increases cost."

National Instruments argues that it can help control development costs, especially for custom products, by providing a single environment where developers can design, prototype, and deploy an application.

The company pitches its software as easy for engineers to use because LabView's graphical interface resembles an engineering flow chart. In addition to its links to SolidWorks and CosmosMotion, LabView recently unveiled state charts that simplify machine and robot programming.

On the hardware side, National Instruments controllers can run LabView models as control programs without any changes. The controllers use high-speed input/output and a high-speed field programmable gate array processor. This processor is not only more reliable than a PC, but crunches complex algorithms fast enough to handle control, and analog sensors and vision systems at the same time. (Vision, in particular, often requires a separate control system on robots.)

The result is a solution that simplifies complex programming and handles the sensory input of today's more complex machines. "PLCs are good for handling simple instructions, input/output, and power," Gomez said. "But when you're interfacing with a vision system or need to store the amount of torque applied to a part for traceability, this is a much better way to go."

Although National Instruments has made inroads in machine and robot development, much of the work is done on campus. Engineering schools, which use LabView to instrument experiments, are increasingly using it to program and control devices.

Dobberstein admits that industry presents a tougher challenge. Some companies want PLCs only on the shop floor. But as machines grow more and more complex, National Instruments is betting that LabView's combination of speed, flexibility, and graphical simplicity will find it a niche.

In the larger scheme of things, energy-efficient bearings are probably not going to reverse global warming or save the world. Yet Sweden's SKF Group believes it can make a difference. It has introduced a new line of energy-efficient deep groove and tapered ball bearings that promise to use at least 30 percent less energy than their conventional counterparts.

SKF uses a combination of materials, machining, and design to achieve those gains. The new bearings are machined to far tighter tolerances than were possible even a decade ago. They are housed in a lightweight polymer cage, and they contain fewer balls or rollers.

Energy- efficient bearings promise to reduce bearing energy use at least 30 percent.

In the past, fewer rolling parts would have put additional stress on each moving part, accelerating the formation of cracks around defects in the steel's crystalline structure. Using higher-purity steel (without changing the grade) reduces the likelihood of cracking. Improved machining also reduces stresses (and cracking) generated by even micrometer-high variations in roundness.

SKF says that avoiding stress caused by rolling variations lets it reduce the number of rolling elements (each of which generates friction) in the bearings. The smoother movement of the rolling elements requires less force to keep them evenly spaced, and so SKF was able to substitute lightweight polymer for the traditional steel cage.

The new tapered bearings maximize energy savings at slower rotational speeds. SKF plans to sell them for industrial and marine transmissions, railroad applications, hydraulic pumps, and wind energy turbines. Simulations show that deep groove bearings save more energy at high rotational speeds. They are targeted at medium to large electric motors, gearboxes, compressors, and fans.

SKF readily admits that bearings waste only 0.6 percent of the total energy used to drive a typical 80 percent efficient industrial motor. Yet such motors are turning all the time. According to SKF, industrial electric motors alone consume 16 percent of all the electricity generated in the United States and European Union, or 1.36 trillion kilowatt-hours per year. That means bearings alone waste 8.2 billion kW-hours per year.

A 30 percent reduction in that number is still a very big number. In fact, as SKF president Tom Johnstone points out, if all those motors switched to the company's energy-efficient deep groove bearings, the energy savings would power 250,000 Swedish households for one year. Adding a single energy-efficient tapered bearing to the gearbox of a 2 MW wind generator would generate an additional 2,600 kWh a year. Replace all five bearings and the turbine would put out an additional 20,000 kWh annually.

The problem is how to sell the bearings. SKF charges a premium for them (although Johnstone would not say how much). Its direct customers, however, tend to make motors and gearboxes that they sell to other companies. They want to cut costs, not increase them, and have no incentive to pay for energy-efficient bearings unless their customers demand them.

Johnstone said SKF has begun a campaign to persuade end users to pay more for high-efficiency bearings that will reduce their lifecycle energy costs.

home | features | breaking news | marketplace | departments | about ME back issues | ASME | site search

© 2007 by The American Society of Mechanical Engineers