Marginal Column

With efficiency and precision.

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Camilo Orjuela - Manager Sales
Semiconductor and Electronics Technology Center

Our digital world uses manufacturing systems engineered to move and process extraordinarily complex products -- semiconductors, LEDs, disk drives -- with micron-level precision.

For example: a builder of hard disk drive processing equipment needed to move disks through multiple vacuum deposition chambers with extremely high levels of stability and very complex motion control requirements. Camilo Orjuela’s U.S.-based team of motion control engineers took up the challenge.

“We really begin by listening very carefully to our customers, understanding their problems, their challenges,” Orjuela said. “Then we apply the engineering tools and the capabilities built into our products to fit exactly what they need done. What we don’t do is try and force a solution, fit a round peg into a square hole.”

The challenge the disk drive manufacturer presented was this: how to use a linear motor system to move the disks that are being processed through a vacuum chamber, without trailing cables or power lines for the linear motors inside a vacuum; otherwise, special feed-throughs would be needed to pass the power and control cables from outside the chambers to within, plus the cable coverings can outgass in a vacuum, contaminating the disk processing.

Camilo’s team re-engineered a Rexroth linear motion system in a solution that literally turned the technology inside out: Rather than locating the linear motors within the vacuum chamber, the Rexroth Linear Motion System (LMS) uses inverted linear motors with coils embedded in the chamber walls and a magnetic plate mounted to each disk carrier.

The plate on the carrier is then magnetically coupled to the coils, which are located outside of the vacuum chamber. The carrier moves when the electromagnetic coils are activated in a precisely controlled sequence, utilizing an advanced Rexroth motion control system.

“With this solution there are no cables, sensors or other mechanical drive elements to generate debris in the chamber—eliminating a possible source of contaminants that could cause defects to the disks as they are fabricated,” Orjuela said. “Plus, we were working within the realm of microns of precision, in terms of motion and endpoint control.”

Since implementing the solution on the processing equipment, disk carrier transport time has been reduced by 50 percent and throughput increased from 800 to 1000 disks per hour, a 25 percent gain over prior system.

“They understood vacuum deposition, we understand motion control like no one else -- so we combine their knowledge with our knowledge and solved the problem together.” Orjuela added.