Integrated actuators such as Exlar’s GS40 eliminate the costs associated with assembling an actuator, motor, screw, and bearings.

If only pricing motion systems were as simple as a stock boy gunning price tags onto cans of chopped ham.

Between factoring in value-added supplier services, time-to-market factors, operation costs, and maintenance expenses, the total cost of motion system ownership is often a large, elusive number. While acquisition costs may come to mind, the bills don’t stop there. Motors, for example, can use 40 to 60 times their initial purchase price in electricity over a ten-year life span.

Fortunately, hidden expense traps are avoidable and cost estimation tools can help you make wise purchasing and procurement decisions.

A systematic approach

Keeping costs down begins with smart shopping. For example, on industry average, buying an integrated system offers a 25% savings over buying separate components, according to Bayside Motion Group, Port Washington, N.Y.

“Typically, a large part of the cost of a motion system is the integration of the various components, that includes the cost of specifying and procuring each, as well as engineering costs,” says Avi Telyas, CEO, Bayside Motion. Ideally, the level of modularity should be such that the motion subsystem can be dealt with as one interaction, one training curve, and one commercial relationship as opposed to many.

Bayside Motion helps alleviate costs by taking motor, gear, and slide technology and putting it “under one roof.” For example, Bayside’s Stealth gearmotor combines a gear and motor, and its linear positioning stages have embedded motor drives. Having one component instead of two provides a more reliable system because there are fewer parts, as couplings, bearings, screws, and wiring are reduced or eliminated, says Telyas.

Integrated components are designed with better line-ups and typically run cooler than separate combinations. A system that runs cooler, of course, lasts longer. Integrated systems also are up and running more quickly, which allows more room to explore settling times, servo stiffness, response times, and other dynamic factors.

One question people often have about integrated systems concerns repair. In order to repair the motor, the whole system must be removed. Telyas says, “The truth of the matter is if you’re down, you’re down.” It’s the same level of difficulty to swap out an integrated system as a single component.

Longer life and fewer parts to contend with are some of the cost advantages of the Stealth integrated planetary gearmotor from Bayside Motion.

Animatics Corp., Santa Clara, Calif., is another component manufacturer offering integrated packages. With its SmartMotor, a motor, encoder, amplifier, and controller all built into one unit, system acquisition cost goes down, and maintenance costs are significantly reduced. Once the SmartMotor is in the field, a spare system can be stored and quickly swapped out, unlike a conventional system with a motor, cables, cabinets, and a controller.

Even higher levels of integration may be on the way. Bayside’s next step, says Telyas, is to include some of the drive electronics inside the positioning system or gearmotor itself. Bayside is waiting for the necessary miniaturization of electronics, but expects that to happen within the year.

Downsize downtime

While the component purchase price is important, the real cost of a product is the cost of failure, says Telyas. “Number one: never skimp on reliability,” he advises.

Welker Bearing Co., Troy, Mich., which specializes in PTFE self-lubricating bearing material products for such inhumane environments as welding lines in automotive plants and foundries, provides maintenancefree products designed to last the life of the program – and not cause downtime. Their components, including shot pins, slides, and lifts, come with a three-year warranty. While Welker’s shot pins are by far the most expensive on the market, they are standard at some DaimlerChrysler and General Motors Corp. facilities, says Thomas, because of their longevity. On an automotive assembly line that produces one to four cars a minute, the cost of downtime is far greater than the shot pin price tag; especially considering that the “buffer” of auto parts, conveyors of doors, and hoods, etc., must be re-stocked before starting the line again.

Continue on page 2