Manufacturing Motion Control | CNC Control

Manufacturing & motion control

The motion control industry is changing. Current trends include direct drive motors, a move to electrical solutions, open architecture, and standard communications and interfaces," said Philip Hollingsworth, director of engineering at California Linear Devices. These trends are bound to persist over the next decade and more.

To respond to ever-increasing competition, motion control system designers will continue to seek ways to reduce system costs by eliminating or consolidating the number of system components. Frank P. Monteleone, senior director of worldwide sales for Thomson Airpax Mechatronics, cites an instance of trend. "An example is the increased use of sensor technology for simplified position feedback. Reducing the number of system components also decreases the assembly time, and improves reliability. Since there are fewer components, there will be less system maintenance and increased mean time between failure (MTBF) ratings for the customer's product."

Prominent among trends in the coming years will be the growth of the use of microelectromechanical (MEMS) devices in motion control instrumentation. Marketing firm Frost & Sullivan estimates that the total MEMS market, now at $1.4 billion, will increase at a compound annual growth rate of 17 percent through the year 2004, when the market is expected to exceed $3 billion. Automotive applications such as airbag inflation sensors currently make up one third of the total market, followed by the medical market, which uses MEMS in products like disposable blood pressure sensors.

But there are numerous applications that are certain to reach the market in the coming decades. These could include smart munitions that can alter their paths after firing, metering nozzles for inkjet printers, drug delivery systems, accelerometers used in antilock braking systems, and sensors for measurfing fuel level, tire inflation, and oil pressure. Applications in the photonics industry abound, including reliable telecommunications switching devices.

MEMS-based designs can produce systems on a chip in which a transceiver, batteries, sensors, and microprocessors are all on a single component not much larger than a postage stamp. They are rugged - many will be made of silicon, which is many times stronger than steel - and can operate for long periods with little power. The challenge for the years ahead is to create components able to endure internal heat buildup and withstand excessive structural loads, ambient temperature swings, and severe shock and vibration. But few doubt that these devices have a bright future.

The near future will see changes in encoders as well. Already in evidence are optical encoders that use fewer components, yet provide better reliability and performance at lower cost.

According to Edward Burk, technical sales manager at Renco Encoders, "Component reduction is being done by incorporating the optical sensors and conditioning circuitry into a single, application-specific integrated circuit (ASIC). By reducing component count on the encoder, you open up valuable printed circuit board space, allowing additional capabilities to be integrated with the encoder. Future developments will add memory to contain encoder data, user data, or both, and a communication bus to transfer this data to external devices."

Thomson's Monteleone sees a similar push toward integration in the world of motors and controllers. He notes a trend away from high-torque, closedloop multiple device systems with separate motor, control electronics, power supply, and feedback devices, toward "having everything necessary to perform all of the functions required in one package." He added that "surfacemount, field-effect transistors are a driver of this trend. Power needs can be scaled down to a lower level. The older servo systems were very expensive."

Nick Johantgen, manager of engineering at Oriental Motor USA Corp., said his company will continue to migrate toward all-inclusive solutions. "The customer will simply input a description of the mechanical system and motion profile he would like to achieve. The solution would then provide the proper motor, driver, and/or controller, and cause these components to execute the motion upon command. This technology will be applied to both rotary or linear motion products with minimal effort required by the user."

In the world of machine vision, George Blackwell, senior manager of marketing at Cognex Corp., expects the drive toward networked machine vision to accelerate. "To catch defects earlier in the manufacturing process and improve process control, companies will distribute vision systems at even more points along the production line. Ethernet will likely continue to serve as the basis for networking the sensors, together with an emergence of new types of industrial networking protocols."

Dimitri Dimitri, president of Delta Tau Data Systems, sums up the changes coming in motion control. "During the next decade, the number of motion control solutions will continue to grow. We'll see a continuation of distributed and centralized architecture, and while old technology solutions are not disappearing, the real growth will be in new technology, resulting in much higher resolutions that increase accuracy. Single-chip solutions will be available for volume applications," he said. "The biggest issues for customers," predicted Dimitri, "will continue to be price performance, simple wiring, and easy setup without sacrificing performance and flexibility. As a result, more commodity-type motion control solutions will be available."

The major trend that affects manufacturing in general - the actual production of parts - is rapid prototyping. Being able to produce prototypes of parts before they are put into production reduces product development costs, time to market, and the chance of producing defective products.

Although still a rather young technology, rapid prototyping has developed quickly in the past decade. 3D Systems introduced the first commercially available rapid prototyping machine in 1987, with a limited choice of materials. The first systems were used primarily in the automotive and aerospace industries, but over the past 15 years, it has become more of a staple in the manufacture of all types of products, from cell phones and medical devices, to computers and consumer products.

Today's rapid prototyping systems incorporate CAU/LAD/UAM software with many types of materials such as plastics and resins to construct, layer by layer, a working prototype of a product or part. Using techniques such as injection molding, stereolithography, and high-speed machining, rapid prototyping machines are available from many manufacturers, including DTM, Stratasys, and 3D Systems. Desktop-sized machines, called 3D "printers," also are becoming more commonplace in today's manufacturing environments. As prices for this equipment come down, the use of rapid prototyping could continue to replace conventional methods such as hand carving in many industries.

Philip Hollingsworth of California Linear Devices: End users are getting the best state-of-the-art equipment as it's developed.

George Blackwell of Cognex expects the drive toward networked machine vision to accelerate.

Delta Tau Data Systems' Dimitri Dimitri: More commodity-type motion control solutions will be available.

Copyright Associated Business Publications Dec 2001
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