Cleanroom alternative is portable, expandable, operator compatible and cost effective
by Don Zytka
Miniaturization is reducing the need for large costly cleanrooms. Competition is making them inefficient. Modular cleancells are one alternative due to their cleanliness level, controlled air flow characteristics, the ability to easily add as demand requires and ergonomic considerations.
A modular cleancell is a form of minienvironment that can be incorporated in clean manufacturing schemes. Cleancells can be used in the manufacturing of pacemakers, infusion pumps, syringes, prosthetic limbs, computer peripherals and microelectronics.
One of the greatest benefits of the modular cleancell is that it is not product specific but can be tailored to a specific process or operation. If one requires an IV setup, it can be added; if one processes syringes with robotics, it can be designed to fit; if one requires an ESD-safe work zone, it can be setup; if one wants a conveyor to move product, it can be done.
The goal when setting up a modular cleancell system is to establish an environment that will isolate the product or operation from contaminants while being portable, expandable, operator compatible and cost effective. Some factors to keep in mind when planning a modular cleancell system are to develop a system:
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This scenario equates to an approximate 60 percent saving in cleanroom floor space. Over 80 cleancell workstations could operate in the space required for the cleanroom.
Education is important when you are developing a modular cleancell system. Your management, operators, engineering staff and customers are familiar with standard cleanroom operation. Outlining and demonstrating the benefits of the cleancell system is essential. Management and internal personnel have been quick to realize the benefits. On the other hand, your customers and regulating agency must be convinced that this system will perform as well as, if not better than, the systems they already know. For this reason the cleancell must not only meet and exceed all functional requirements it must also function as well as a high-quality cleanroom. To accomplish this it is important to meet the following design and purchase criteria.
The internal cleanliness rating must meet the users' operational cleanliness requirements. Modular cleancells should have the option of HEPA or ULPA filtration and the ability to overcome obstructions to standard airflow patterns.
The cleancell should incorporate a filtration system that will permit it to operate in a non-cleanroom environment or in a cleanroom. Careful selection of a prefiltration system and specification of fan motors is essential.
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The design must ensure product or process protection from cross contamination between cleancells while giving the operator an open interface from one cleancell to the adjacent one. This can be accomplished through airflow techniques and the placement of shields and barriers.
Design for a minimum external footprint. A cleancell is designed for space efficiency. Ideally, it should fit through standard doorways so it can be located in a lab or research office. If the cleancell is being used as part of a manufacturing process the objective is to maximize the “product per square foot” capabilities of your site. Resist the temptation of oversizing. It can be cost effective to downsize your tooling and increase the efficiency of your process to fit into a smaller cleancell. Sometimes too big is too much.
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The interface must meet the ergonomic needs of operators whose height may span 4'6″ to 6'2″. Operator fatigue affects quality and efficiency. The operator must have the proper lighting, hand and arm movement, and seating posture.
Each cleancell should have the capability to operate independently so a total system is not affected if one cleancell is disrupted. The cleancells should also be able to operate as a single system and when required be linked with other cleancells or clean systems.
Each cleancell should be designed with “on-the-fly maintenance access.” No cleanroom operation can afford extended downtimes. There should be quick access to system controls, effective part replacement techniques and if necessary the ability to easily replace a cleancell. The recovery time of a cleancell after cleandown should be minutes.
Easy access to tooling and processes can be accomplished with panels that are easily removed or hinged.
Process utilities should be located in the clean envelope and should meet all of the process requirements.
Don Zytka, president of Clean Zone Technology LLC, a Denver-based company, has spent the past 20 years in cleanroom planning, project management and integration in the development of clean manufacturing sites in the U.S. and Far East. He has been issued a patent as the inventor of a Class I Minienvironment (cleancell).
Traditional minienvironments vs. modular cleancells
A minienvironment is generally perceived as an independently operating, sealed, ultra-clean containment that isolates a manufacturing process from the surrounding low level or non-cleanroom environment. The minienvironment has the capability of delivering clean filtered air in the vertical or horizontal direction. There is generally no direct operator interface to these systems and part introduction is done via an automated clean transport.
A modular cleancell incorporates the features of standard cleanrooms, flow benches and minienvironments. A modular cleancell should be flexible, versatile, ultra-clean and independently functioning. It should have the capability of establishing an environment to meet your cleanliness requirements and an envelope to accommodate your process. It should have an open operator interface while protecting the product or process from external contaminants. Ideally, it should be designed to operate in a non-cleanroom controlled environment, where only modified gowning is required, while maintaining a high degree of contamination control. Modular cleancells should have the capability of operating independently or, if required, in conjunction with companion systems or other clean manufacturing devices. It should address operator and material interface and the elimination of excessive cabling for process equipment hook-up. — DZ