To determine the most appropriate Cleanroom Wipers for a specific task, consider the five C’s; Cost, Capacity, Cleanliness, Chemical Compatibility, & Construction.
Cost: How much is each individual wiper? Is the wiper the full published size? Be cautious of wipers that refer to their sizing as nominal. Make your costing comparison on actual wiper size. Compare individual wiper cost per surface area to calculate the total cost per swipe. A ¼ folded cleanroom wiper has 8 unique swipes.
Capacity: How much liquid can the wiper hold? Higher sorbent capacity means that the wiper can hold more cleaning chemistry. Substrates such as non-woven poly / cellulose and cotton are inherently absorbent in their fiber structures. Woven knits such as polyester and nylon, the chemistry is trapped in the crevices of the fibers. This is adsorbent.
Cleanliness: Is determined by particle count testing, either Air Particle Count Testing (APC) or Liquid Particle Count Testing (LPC). More stringent cleanroom wipers are tested for extractable and their Ionic contaminant to look at the chemical characteristics of the contaminant. All cleanliness testing should be done per the IEST Testing standard IEST-RP-CC004.
Chemical Compatibility: Is your wiper substrate compatible cleaning solvents? If the chemistry is not compatible, the wiper will potentially break-down, and release contaminating fibers. Thoroughly analyze all cleaning agents and chemicals to prevent unintended consequences with a non-compatible wiper.
Construction: This relates to how the material itself is constructed and its edge treatment. Wiper fabrics are made from synthetics, natural materials, and blends. Synthetic materials such as polyester and nylon are typically used for critical cleaning (MicroTek / NanoTek). Nonwoven blended wipers are most commonly used for non-critical, environmental / facility cleaning (MacroTek). Natural fabric wipers (i.e. cotton) tend to be used for specialty or high heat applications. The wiper perimeter is a significant contaminant source, if the edge treatment is not appropriate to the material type. For example, polyester wipers made from the same fabric can have drastically different levels of contamination based on the way its edges are cut and finished. The predominant wiper edge treatments are: cold knife, laser edge, ultrasonic edge, and pressure heat seal edge.
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