Guides from Rollon feature the abilities to carry heavy load and compensate for misalignment — the latter being a consideration required for realistic design modelling.

In an effort to match the accuracy of bearing-type guides without the drawbacks, Schroeder's company uses a simultaneous integral milling operation to machine critical surfaces of an aluminum extrusion to less than 0.001 in. or 0.025 mm over a 6-m length, in the same range as some steel recirculating ball-bearing guides, also known as linear guides or profile rails. Aluminum, by itself, is too soft to be a good bearing raceway so it must be hardened in some fashion: For cam roller and recirculating ball bearings, machined aluminum frame is fitted with a steel race for longer bearing life. The mechanical crimping system used to secure the races also eliminates labor-intensive fasteners.

“There were a few applications that led us to develop our integrated V-track linear guides,” says Michalske. One application used two parallel rails mounted to an aluminum plate. The customer had a tight parallelism tolerance and their assembly line staff would spend hours trying to align the two rails. In the other application, a customer was using two linear guides mounted to a 100×200-mm aluminum T-slot structural frame. This customer did not machine the frame prior to assembly and would sometimes spend hours trying to align the linear guides so that they would move easily without binding. “Both systems now employ custom-designed integrated rail-carriage systems that decrease installation and alignment time to almost nothing,” says Schroeder. In short, the machining of simultaneous integral milling allows for dimensional accuracy and parallelism at a lower price point.

Looking to the future

Two areas to watch are super-efficient and small actuators. “Eventually, there will be need for efficient actuators to track the sun, for solar energy; miniature linear-motion systems will also be important, as we push the horizons of nanotechnology,” says Schroeder.

His company's stance is that efficiency and green engineering are ways of life for any company that expects to be around a few years from now.

Another area of growth is custom solutions. “For the price of an aluminum extrusion die and a few consulting engineering hours, we can supply a custom solution,” Schroeder says.

Their guide's aluminum extrusion dies range from a few hundred to a few thousand dollars, depending upon size and die complexity. Customers can do a simple ROI calculation to determine if the initial investment in a new extrusion die will yield return enough to justify the engineering change.

Generally speaking, customers spending more than $5,000 a year on installation, assembly, and alignment find that the switch saves money. “With 250 working days in a year, $5,000 works out to approximately $20 per day; if an average assembly worker makes $15 to 20 per hour, it takes little time to recover that initial investment,” Schroeder adds.

In fact, in the current economic environment, the most obvious trend has been the relentless pursuit of cost reductions. “In many cases, this may simply mean the replacement of components that were originally overspecified with lower cost components that can still get the job done,” says Gingerich of Bosch Rexroth. In others, it might mean that automated systems are replacing manual operations, and linear motion components are needed as part of the final automated approach.

“We believe that through innovation we can continue to achieve success,” concludes Cook of Rollon. “Design around what is. Don't just add onto existing products. Distill. Improve.”

For more information

Bosch Rexroth Corp.

Linear motion
Assembly technologies
(704) 583-4338
www.boschrexroth-us.com

PBC Linear

(888) 389-6266
pbclinear.com

Tolomatic Inc.

(800) 328-2174
www.tolomatic.com

ROLLON Corp.

(877) 976-5566
www.rolloncorp.com