Sunday, September 26, 2010

Clean Room: Clean Robot

While certain industries have suffered under a straining economy, many requiring cleanroom manufacturing are growing. Cleanroom robotic solutions will play a key part in this growth. What do you need to know about cleanroom robots and equipment to service this market? How are they different from traditional robots? What about certification, maintenance and those pesky particles? Following is a quick guide to all things clean when it comes to robots.
By virtue of its name, cleanrooms control the level of particle contamination present that can potentially degrade the products being manufactured. Cleanrooms are classified according to the number and size of the particles permitted per volume of air. For example, a Class 10 cleanroom denotes that no more than ten particles of 0.5 ยตm or larger and zero particles of 5.0 or larger are permitted per square foot of air. Contaminants can be generated by people, process, facilities and equipment. In order to control contaminants, the manufacturing cell and in many cases the entire room must be controlled. Robots used in this environment must meet stringent cleanroom certification requirements to prevent them for acting as a source of contamination.
The Robots
Adept Viper 850CR: Six axis cleanroom robot
How do cleanroom robots differ from their standard counterparts? Much of the hardware used in a cleanroom robot is the same as any other robot with the important exception of a combination of sealed covers (to prevent particles from escaping the robot), stainless steel hardware, proper non-gassing lubricants and vacuum to evacuate any internally generated particles. "Robots designed for cleanroom processes have special considerations for harnesses. From a design standpoint the harness can be a serious particulate generator and a major design challenge for clean applications," said Scott Klimczak president of CHAD Industries, a pioneer in the area of wafer and substrate handling WLP I (Wafer Level Packaging) applications. "Understanding the harness requirements and how the robot design will integrate a harness should always be stressed in the robot selection." 
As a matter of practice, materials prone to particle generation are substituted or coated to eliminate the potential for contamination of the manufacturing area and ultimately the components being processed. Depending on your application, cleanroom robots can be linear, SCARA, six-Axis or delta/parallel-type robots but they all must meet strict cleanroom certifications.
Robot Certification

External harness example
Certification is done by counting the number of particles that are generated when the robot is in motion. For this process the industry employs particle counters which have to be calibrated to meet or exceed the standards set by NIST (National Institute of Standards and Technology). In addition to NIST traceable practices, other standards of particle counter calibration include Japanese Industrial Standard (JIS) B 9921, Light Scattering Automatic Particle Counter, and ASTM F 328-98, Standard Practice for Calibration of an Airborne Particle Counter Using Monodisperse Particles. It is important to fully understand your requirements and the standards they adhere to. Adept Technology, Inc. a leading U.S. based manufacturer of cleanroom robots tests robots both internally and through third party testing and certification to ensure integrators and end-users deploy their equipment appropriately. "Our robots are designed for high speed, precision applications frequently involving vision guidance. The challenge with this market segment is that it demands careful consideration of not only the components used to develop a highly robust manufacturing process but the manner in which they are integrated has significant impact on the ultimate cleanliness of the cell," said Rush LaSelle director of worldwide sales and marketing for Adept Technology, Inc., a leading manufacturer of intelligent vision-guided robotics. "The success of an installation is heavily dependent on tightly integrating engineering and sales teams.

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