Written by Albert Greenhut
Back in the 1950’s and 1960’s the “cleanrooms” of the day were operating rooms. These rooms were cleaned and sterilized to reduce contamination and germs. The main focus was on germs, not on particles. In today’s standards these operating theaters were basically class 300,000 rooms. Particles in the air (number and size) were not a consideration in reality, since particles do not impact healing or contamination, germs and microbes do. By necessity these operating theaters were also highly ESD sensitive – not because of the equipment being used, but because of the ether being used. Ether is a highly explosive and flammable gas, so sparks and ESD events had to be controlled – which was why the requirement for medical packaging for operating theaters was to be ESD safe.
Jump ahead to the 1970’s when ether was being replaced and electronics were becoming faster, smaller and more present. Suddenly these electronics were being impacted by particles in the air, during their manufacturing process. Electronics utilize metallic conductive paths that allow electricity to flow down them. As the electronics were shrunk down, suddenly even small particles in the air, such as dirt or other airborne contaminants, can cross over more than 1 of these conductive lines or traces. If that particle is conductive to begin with, or becomes hydrated (absorbs water) these particles can literally short out the circuit by providing alternative paths for the electricity to flow. So, controlling these particles in the manufacturing area became critical – just like manufacturers making aerospace and space electronics and assemblies found out in the 60’s. So the new cleanrooms became the manufacturing assembly areas for high-end electronics. Suddenly class 300,000 became class 100 cleanrooms. This change put pressure on manufacturers, since the standard “industrial clean” bag manufacturing operations are in the range of about class 100,000 – not clean enough for bags to be made and be acceptable in the cleanrooms.
Companies like Purestat recognized this change and set up class 100 cleanroom manufacturing areas within their plants. Purestat took additional steps beyond just installing cleanrooms; we also looked at our anti-static technology, our in-house lamination process and all of our clean structures. We designed structures that are stable and easy to clean. We also looked at the mechanics of the film manufacturing process, knowing that there are ways and processes that we can do to minimize the particles coming in contact with our films. Typically the inside of our film tubing is between class 50 to class 100 right off the production line. Talk to us and we will be happy to describe some of our magic. Purestat, we go above and beyond to meet and exceed our customer expectations and requirements.
Written by Albert Greenhut
We at Purestat talk a lot about our ESD product lines; our business was born out of finding unique and effective ways to protect static sensitive items. Dissipative materials take electric charges that are trying to move to an object, like a computer chip, and safely move them away. That sounds vague, but take a look at the picture below. That is the ground after it was struck by lightning. It is obvious that the lightning passed through the ground after it struck, leaving this tendril pattern. A similar thing happens during a static shock when one touches a doorknob the built up static charge that he or she has discharges and moves through their body and to the door handle.
When that person is handling electronic components, like microchips or other metals, this same thing happens. The issue is that sensitive components, like my oft used example of microchips or motherboards, are easily damaged from charges that are made up of less voltage than static shocks, many times the charges that would damage sensitive components is small enough that humans can’t even sense or feel them. So the same discharge is happening on a much smaller scale.
Because these components rely on smoothly transmitting electricity any pinch points caused by electro static damage can slow or even halt the flow of electricity to the component trying to draw power. This is why manufacturers use ESD packaging, to either not build up static charges during the manufacturing, handling, shipping and storage of the items, or to safely dissipate and discharge the built up charge before it becomes a problem like the photo below. ESD packaging also helps separate the human element, to make sure that any charge on us is not delivered to the electronics in an uncontrolled way. Our full line of ESD packaging, from the humidity independent BlacStat™, RIBS MVTR and Static Intercept® to the anti-static PureStat poly, shielding and barrier lines all have years of positive track records of protecting all types of electronics, aerospace parts, military assemblies, etc. for our customers. Let us know the application and we can steer you into the right product. Please visit us at www.PureStat.com for more information.
Written by Albert Greenhut
My last post was about the summer turning to fall in New England. Now fall is turning to winter and the days are getting shorter. But the days that are the darkest are when Blac-Stat shines brightest. The reason is that as fall turns to winter the cold air gets drier. This environment is when ESD charges build up, exemplified commonly as more and more shocks due to static electricity.
Humans constantly build up charges, but we usually discharge in ways that aren’t as obvious as a spark, for instance after walking across a carpet (creating up to 18,000 volts) and touching a doorknob, or sliding off of a chair (creating up to 12,000 volts). A human cannot really sense an ESD event or discharge of less than 7000 volts, far more than what can damage sensitive equipment like computer chips, even much smaller discharges can cause irreparable damage to expensive components, either killing them dead or creating what we refer to as the walking wounded. These walking wounded chips, boards or electrical assemblies will generally fail before their expected life span is up – also referred to as latent defects, a serious issue with electronics.
The beauty of Blac-Stat is that its conductivity does not depend on humidity, meaning that it will protect valuable electronics through the winter, as well as all other times of year. Typical anti-stat bags and films (including shielding bags) use either coated anti-stats or internally loaded anti-stats. These anti-static materials depend on having moisture on the surface of the plastic in order for it to conduct electricity. Below 12-15% humidity there is insufficient moisture in the air / on the surface to provide any ESD (anti-static) behavior. With Blac-Stat that is never a problem since its electrical properties never change, regardless of high or low humidity.
Blac-Stat material is also non-sloughing. Typical conductive films use carbon that is not locked into the structure of the polymer and that means carbon can slough off (shed) and get into what the film is supposed to be protecting, and in the case of sensitive products this can cause failures. Blac-Stat is carbon loaded polyethylene but the carbon is locked into the structure of the film and will not shed.
As we move towards winter many things will change, the quality of your goods should not be one of them. For more information on Blac-Stat please visit us at www.PureStat.com or find the Blac-Stat Spec sheet here.
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