Applimotion is an innovator in the field of direct-drive solutions thanks to its focus on leading-edge servo motor applications. According to Rob Mastromattei, marketing manager at Applimotion, "We develop engineered solutions based on our proprietary servo motor technology. In this metrology application, we used MicroE Systems' Mercury™ encoders with our HO Series servo motor. This hybrid design allowed us to create a rotary stage that bridged the performance gap between a typical servo motor and an expensive high-precision direct-drive rotary stage." Today, this rotary stage is at the heart of a new metrology system used in the manufacture of semiconductor components.

Before specifying the HO Series rotary stage, the motion platform of this metrology system was running open loop. The choice of motor compromised system accuracy and restricted throughput. In addition, the motor resulted in undesirable heating effects. The HO Series rotary stage, with the Mercury™ encoder, eliminated these problems. A bolt-in NEMA 23 size replacement for the old open loop motor, the HO Series rotary stage dramatically improved point-to-point measurement accuracy. And throughput was significantly higher. "The performance, price and easy integration of the HO Series rotary stage made it a logical alternative," Mastromattei noted.

The selection of motion feedback device was critical to converting the HO Series servo motor into a high performance stage. MicroE Systems' Mercury™ encoders were the preferred choice for a number of reasons. The first was choice. The Mercury encoder family contains 21 models that produce high-resolution quadrature output right from the sensor head. This made it easy to offer the HO Series stage with a range of resolutions. What's more, it insured easy integration with any controller that accepts quadrature signals. With the Mercury 1500, the HO Series stage is available with a choice of four fixed resolutions. With the Mercury 2000 encoder system, the HO Series offers integer selectable interpolation levels from x4 to x256. This enables the hybrid stage to operate at resolutions from 288k CPR to 7.37M CPR, or any resolution in between.

In addition, the Mercury encoder sensor has the smallest Z-height, and thus it minimizes the total stage's axial dimension. And, Mercury's robust double-EMI shielding insures reliable motor performance, regardless of the end use application.

Custom capabilities were essential to the success of the HO Series stage. MicroE Systems was willing and able to produce custom large-through-hole rotary scales. The company worked with Applimotion to meet its time and cost constraints. "No other supplier was willing to go the distance for us," claimed Mastromattei.

The final element of the success story was MicroE Systems' application support team. MicroE provided the necessary on-site training to support Applimotion's manufacturing ramp up. A critical aspect of proper encoder operation is the correct mounting of the scale to the hub/motor interface. Accurately mounting the rotary scale minimizes eccentricity error and optimizes the HO Series' performance.

All in all, the combination of Applimotion specialty servo motors, Mercury encoders and MicroE Systems' applications support resulted in a product that was readily embraced by the semiconductor industry. According to Rob Mastromattei, "We couldn't have asked for a better partner than MicroE Systems. They had the technology we needed and the support to help us get to market fast."