Coupling Eliminates Backlash Potential in IC Seam Sealing Systems

Zero-Max ServoClass Coupling in the Seam Sealer System provides an effective connection of servo motors (50 to 100 oz.-in.) to ball screws while effectively handling sensitivities required in the servo-driven system.

Production of integrated circuit packages at high speeds requires a backlash-free motion system to produce the highest quality seal. These sealing systems have digital sealing power that allows pulse-by-pulse control of power, giving maximum control and response to seal conditions.

Solid State Equipment Corporation, Horsham, PA, a technology leader in manufacturing systems for the semiconductor and microelectronics industry, recently introduced a new line of parallel Seam Sealers driven with servo motors. These systems provide linear- and rotary-weld sealing with real time force control and automatic package height sensing for seal uniformity. In designing the drive system for these Seam Sealer Systems, Ray Regan, design engineer for Solid State, decided to connect the servo motors to the ball screws with a coupling. He chose the ServoClass coupling manufactured by Zero-Max, Minneapolis, MN, designed specifically to handle the sensitivities required in a servo driven system.

"We looked at other couplings, including those with steel, accordion-type center members," reported Regan. "We ruled them out because we needed the best torsional rigidity in our servo connections in order to eliminate any possibility of backlash that could affect the servo controls' positional accuracy and dynamic stability."

Parallel Seam Sealer Uses Couplings for Pick-and-Place and Positioning System

The automatic lid placing system (XY axis), uses three model SC020 ServoClass couplings (.25" x 8mm bore), which raises and places the lids for sealing. The vacuum pick-and-place head lifts the lid from the lid bin and accurately places it on the package using a dual optic system. One camera locates the lid position and a second camera determines the position of the package for accurate placement and tacking prior to sealing.

Precision sealing of integrated circuit packages at high speed requires a backlash-free motion system to produce the highest quality seal.

Providing an operating torque of 13 in-lb. (1.5 Nm), the SC020 operates efficiently and smoothly in the Seam Sealer System. Maximum rated speed for the coupling is 10,000 r/min. with the Seam Sealer System operating below that at its highest acceleration speeds.

"It is very durable and has no maintenance requireme nts once installed," reports Regan. "Once in place, we can forget about it."

Coupling Has High Torsional Stiffness And Low Inertia

The ServoClass coupling has flexible, stainless steel double discs and keyless clamp-type mounting hubs. Its design features zero backlash, high torsional stiffness, and low inertia -- all critical issues in demanding servo-driven systems.

Designed to meet precision positioning requirements and high reverse-load characteristics of AC and DC servomotor applications, these couplings are very flexible because of the double-flex disc design. It is this design that provides exceptional misalignment capacity, while the coupling flexibility also reduces reaction loads. The result is smoother system performance and longer operating life of the connected components.

--KC

For more information:

Circle 556 - Zero-Max, Inc. or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/006df-556

Circle 557 - Solid State Equipment Corp. or connect directly to http://www.1rs.com/006df-557