Biting the Dust: Clean Room Tools Uphold Quality and Safety Standards

Devices that we depend on every day can be reduced to uselessness by something as small as a single speck of dust in the manufacturing plant. The satellites that orbit far above our heads, the hard drives in our computers, and the medical devices that keep hearts beating and administer life-saving drugs are all assembled in clean room environments. Clean rooms are marvels of modern design that have set tolerances for particles that can be measured in microns—a measure that is only one-millionth of a meter and typically reserved for bacteria rather than manufacturing.

Clean room tools must be able to tighten fasteners without producing debris that is larger than a microscopic organism—a tall order when a single visible speck will exceed clean room tolerances by several thousand orders of magnitude. Clean room tools must be specially designed to produce no particles during use. The fasteners they turn and the internal mechanism of the tool must not produce metal flakes or chips that violate the clean room environment. It’s especially important to use torque tools that prevent damage to the fastener or the substrate it holds. After all, a single incident can produce particles that can disable products before they ever leave the factory.

Clean Room Air Quality Requirements

The air quality requirements for a clean room are a measure of the size of the particulates that can be found in the air in a cubic amount of space. The US Federal Standard for a Class 100 cleanroom, for example, allows less than one hundred particles, 0.5 microns in size, within a cubic foot of air space. A Class 1000 cleanroom has less than 1000 particles of the same size per cubic foot. Although the US federal standards for clean rooms are still frequently used, they were officially delisted in 2001. They were superseded by the International Organization for Standards (ISO) clean room standards, which have an approximate equivalency.

A complete break down of the clean room classes allowed by US Federal standards, along with the ISO equivalent, can be found in the chart below:

ISO standards do provide a rough equivalent to the old US standards. There are, however, more focused on categories of clean rooms rather than particle amount. They range from the ultra clean ISO 1 clean which, with a tolerance of .1 micron, actually counts the flu virus as measurable particles to be removed. At the other end of the scale, ISO 9 standard clean rooms aren’t that much different than exterior air out on the street. A complete list of the clean room standards recommended by ISO is below:

The difference in the number of particulates allowed between the two standards in cases where they are stated to be equivalent is due to the switch from measuring volumes in cubic feet to cubic meters.

There are many challenges associated with manufacturing products in a clean room. Some manufacturing processes that are used every day, such as milling and machining, automatically violate air quality standards. In order to manufacture clean room products, it’s necessary to use processes like injection molding for medical devices. In the case of semiconductors, new manufacturing processes were adopted. Photo etching carves out circuits by flashing a light reactive substance, but it also helps to maintain a clean room environment.

However, no matter how sophisticated the manufacturing injection, molded housings must be fastened together and electronics must be mounted into their cases while in the clean room. There’s no good alternative to a simple threaded screw. If misaligned, over-torqued, or stripped, these screws can create particulates that are far beyond the level that is acceptable for clean room air quality. This means that maintaining clean air quality requires specialized torque tools.

How Clean Room Tools Help Meet Air Quality Requirements

It is not just the interaction between the fastener and the tool that can violate clean room air quality standards; friction between the tool’s internal components can also create particles that are substantially larger than even an ISO 9 clean room allows. Corrosion on the tool’s surface can create particulate that is several thousand microns in size.

Manufacturing in a clean room environment demands specialized clean room tools with the following features:

• A design that prevents over-torquing of fasteners and damage that can release particulate into the atmosphere.
• Sealed and lubricated internal mechanisms that prevent contamination of the clean room from the tool’s internal systems.
• A corrosion-resistant construction of a high-grade stainless seal.
• A scratch-resistant, polished surface that doesn’t trap particulates or corrode.

Cam-over torque screwdrivers prevent over-tightening with an internal clutch that disengages when the torque limit is reached. They actively stop the stripping of screws and threads and prevent damage to substrates. Preset torque screwdrivers remain within the precise tolerances they are assigned, preventing product damage due to improper adjustment of a tool—precisely what is needed during the clean room assembly process. Clean room torque screwdrivers combine the precision of torque screwdrivers with a specialized stainless steel shaft, sealed and lubricated internal mechanisms, and an anodized handle with Teflon that prevents the creation or release of microscopic bits of particulate into the manufacturing environment. The thorough design of the tool helps preserve air quality in clean rooms.

Keeping these tiny particles out of the air yields big results. Without clean rooms and specially designed clean room tools, we wouldn’t have the global network of computers, the Mars rover, or the pacemakers, MRI machines, and other medical devices that keep us alive. It is no exaggeration to say that clean room tools allow us to see years and worlds that we would have missed without them.