Shielding Bags

25 May

What Are the Standards for Electrostatic Protection?

So, you’ve just been tasked with building or designing your first Electrostatic Protection Area (EPA). You’ve started doing your research, but there are so many choices, from so many different companies. Suppliers, manufacturers, third party providers… If only there was some established standard for judging the efficacy and reliability of all those pieces and parts.

Well, you’re in luck! In 2007, the American National Standards Institute (ANSI) in cooperation with ElectroStatic Discharge Association (ESDA) released a unified set of standards for the design, implementation and maintenance of ElectroStatic Discharge control programs.

In the midst of World War I, five engineering organizations recognized the need to develop standards that could eliminate confusion and could be adhered to across all disciplines, without regard to politics, profits or personal preferences. These groups reached out to the U.S. Departments of War, Navy, and Commerce to form an impartial third party non-profit organization, then known as the American Engineering Standards Committee.

Following the war, the organization spent the next 20 years establishing several safety protocols still observed today, like eye protection, hard hat standards and in-house electrical safety while at the same time reaching out to other similarly tasked international organizations.

When the United States entered World War II, the organization, which would eventually come to be known as ANSI, helped to accelerate the war effort and productivity, created more effective quality control measures, as well as helping to advance photography, radio, and even the development of Velcro.

In 1970’s, ANSI established a public review process and began the herculean effort of moving the United States to the metric system. While the general public never really connected with the metric system, the effort did bring ANSI to the forefront of private sector companies who discovered standardization was a way to stay more competitive in an increasingly global economy.

With the advancement of personal computers in the late 70’s and early 80’s, engineers at several companies recognized a need for more understanding of electrostatic discharge and its prevention. They formed the ESD Association, a non-profit, voluntary professional organization that for almost 35 years has sponsored educational programs and developed standards to help eliminate losses due to electrostatic discharges.

Together, leaning on the historical experience of both military and several commercial organizations, ANSI and ESDA developed the definitive standard for ESD protection, the very cleverly named ANSI/ESD S20.20-2007.

Covering about every conceivable area of ElectroStatic Discharge, the ANSI/ESD S20.20-2007 utilizes both the human body model and the machine model to provide a broad set of guidelines for ESD protection.

The Human Body Model is the military standard that defines and rates the vulnerability of an electronic device to the ESD generated by a human being touching it. The Machine Model works similarly, except it rates the vulnerability of a device receiving a machine discharge into ground. It was originally developed by car manufacturers as their plants moved to more mechanized production technology. The Human Body Model is about 10 times more sensitive than the Machine Model.

There is a lot to explore in the ANSI/ESD S20.20-2007 guidelines, but for the purpose of this primer, the document highlights 3 fundamental ESD control principles:

All conductors should be grounded. This includes the personnel and the surfaces they are working on. We recommend, at a minimum, personal grounding wrist straps, ESD table or bench mats, and a common ground cord.
Necessary non-conductors – certain circuit board materials, device packaging, etc. – cannot lose their electrostatic charge by being grounded and appropriate precautions must be implemented.
Static protective materials, such as ESD shielding bags or ESD totes and boxes must be utilized when transporting sensitive electronics outside a properly prepared EPA.

There are slightly less stringent standards that apply to floors and bench mats, but ANSI/ESD S20.20-2007 is the highest and most comprehensive guideline so far. So when you’re shopping for the parts needed to establish your EPA area, always look for companies that maintain that standard in their products and services.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

04 May

Finding ESD Storage Solutions

There’s a classic scene that appears, with some variation, in every James Bond film. Bond gets assigned a new mission and he goes to see MI-6’s Quartermaster, or “Q.” Q gives Bond everything he needs to complete the mission, including a few items that seem unusual or out of place.

Of course, as Bond fans know, these elements will at some point be combined to facilitate a distraction so Bond can escape. And usually that distraction is a rather large explosion.

One wonders how he was transporting the items before so that they didn’t explode in his Armani suit.

Of course, in real life, when items combine, the result isn’t usually an explosion. Or is it?

As we’ve mentioned before, the amount of Electrostatic Discharge (ESD) required to cause significant damage to sensitive electronics is far below the threshold where a human being can feel it.

By the time our bodies create a static charge that we can feel, it’s somewhere between 3 & 17 times stronger than what most electronics can handle without suffering damage.

Even just the controlled blowing of air, like the old canned air computer dust removal techniques can cause static ESD build-up that can be transferred to your sensitive electronics. And that tiny electrostatic discharge can cause latent or catastrophic failure, costing you time and money.

We’ve discussed selecting the proper shielding bags in a previous post. Another important weapon in your Electrostatic Discharge defense arsenal is anti-static ESD storage containers.

ESD Storage Containers

ESD storage containers are typically made of a conductive material, such as polypropylene or high density polyethylene and provide an added layer of protection, shielding your work areas and personnel from the harmful effects of ESD.

The conductive material provides a barrier which these fields cannot penetrate and prevents the build-up of electrostatic charge. The bins, totes and miscellaneous storage containers come in both static dissipative and conductive. Both control a potential electrostatic discharge, one by resisting it, the other by neutralizing it.

Additionally, be on the lookout for non-ESD protected items that may stray into the Electrostatic Protected Area – transparent tape, plastic sandwich bags, water bottles, Styrofoam coffee cups, even just pieces of paper – can be the source of an uncontrolled electrostatic discharge.

Of course, all of these storage solutions should be used within the minimum guidelines of an Electrostatic Protection Area, that is, wrist straps, ESD mats and a common ground.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

29 Mar

The Truth About 11 Myths of Electrostatic Discharge

Would it surprise you to know that a good portion of our modern world would be unable to function without the help of electrostatic discharges (ESD’s)?

No one seems to know quite how it happened, but in 1984, Scott M. Kunen applied for a patent for a “touch controlled switch” – a device he had developed to allow lamps to be turned on or off with the touch of a human hand.

Little did he know that less than a decade later, computer companies would begin adapting his technology, covering it with a variety of static controlling sheaths, creating the capacitive-touch screen, the basis for all modern smart phones, tablets and touch screen laptops.

So, here’s the truth about the myths of electrostatic discharge.

Myths About Electrostatic Discharge

Myth #1 – All ESD is bad.

The truth is, most people use ESD everyday to make phone calls, send text messages, and create emails. The touch controlled switch and the capacitive-touch screen both operate by transmitting small ESD charges from your body into the devices to signal turning a light on, or the letters or numbers desired.

Myth #2 – Electrostatic Discharge is a modern day problem.

Believe it or not, ESD and necessary precautions to prevent it are older than the United States. In the 1400’s, forts and places that stored or produced explosives, gun powder, and even sawdust could fall prey to horrible accidents, so early forms of ESD control were developed and implemented.

Except, of course, when the good guys needed to blow up the bad guys’ stash in a Hollywood movie.

Myth #3 – ESD problems are really quite rare.

In truth, because of the extremely low levels of ESD required to damage small electronics and the fact that damage isn’t always visible or catastrophic, we may never know just how prevalent ESD events are.

Visible static sparks generated by our bodies have to build up between 500-1000 volts, and it takes twice that charge to be felt. Most sensitive electronics can be damaged by 100 volts or less.

And even if the device continues to function as expected, its life expectancy may be severely diminished and in some cases, latent failure can occur, causing even more damage.

Since we cannot fully prevent or even detect an ESD event, all precautions should be taken to avoid an accidental discharge.

Myth #4 – Discharging fingers and tools before using them is sufficient precaution against ESD mishaps.

Unless you are able to hold your body AND tool perfectly still, you can (and often do) build up a replacement charge that can be discharged into your electronics.

As mentioned above, because of the negligible amount of charge necessary to potentially damage the sensitive parts, you have no way of knowing you are not transmitting a dangerous ESD. It’s better to be safe than sorry.

We recommend that you always use personal wrist straps, dissipative mats and grounding cords for the best chance of circumventing ESD problems.

Myth #5 – You have to touch an item to transmit an ESD to it.

As mentioned above, it takes very little for the human body to build up an electrostatic discharge. Just the movement of lifting your foot off the ground can generate up to 1,500 volts.

And that generated charge can easily leap from your hand to your unprotected device inches away.

Stay tuned next week for Part 2 of The Truth About 11 Myths of Electrostatic Discharge…

We would love to be your full service, seamless ESD solution provider, no matter what your size or budget. Contact us today for more information.

03 Mar

Selecting the Proper Shielding Bags

In Michio Kaku’s book, Physics of the Future, he notes that today’s smart phones have more computing power than NASA had in the 60’s when they were plotting and launching the moon landings.

The latest SONY Playstation can outperform the supercomputers the US Government used in 1997 – 14 years after the movie WarGames.

In 1965, Gordon Moore, one of the founders of Intel, observed what became known as “Moore’s law.” He postulated that computers would progressively become more dense while at the same time increasing their processing speed.

This can be both good and bad news for computers. The bad news being that every time a component gets 10% smaller, it gets 10x more sensitive to electrical shocks, even those coming from simple static electricity. Static in your workplace can be dangerous and expensive if you’re not properly prepared.

One important weapon in your arsenal for defense against Electrostatic Discharge (ESD) is shielding bags. Which bag is best? They all have their pros and cons to consider.

Pink Poly Bags

The earliest defense against ESD was created in the 1960’s. Dissipative Poly Bags, usually referred to as Pink Poly bags because of their unique color – introduced as an easy way to differentiate their static control abilities from standard plastic bags – are coated with a chemical that resists static.

Unfortunately, Pink Poly bags have no shielding capability. An ESD of any significance will travel through the bag and potentially damage components inside. They are best utilized today to package support or processing materials that do not themselves need shielding.

The antistatic properties of the bags help to protect sensitive components near the bags. This makes them a helpful solution as opposed to normal plastic bags, but you should always have a grounding system in place – mats and personal wrist straps at a minimum.

Black Conductive Poly Bags

Black Poly Bags are obviously a step up from their Pink predecessors. But in this case, their advantages are also their biggest flaw. Like the Pink Poly’s, the Black bags are antistatic, with the added benefit of some conductivity, designed to help protect its contents from ESD’s.

The problem lies in how quickly the bags dissipate the electrical charge. The rapid discharge of the ESD can actually generate a spark between the person or object creating the charge, and because the bags lack an additional insulation layer inside the bag, that charge can easily penetrate it.

Plus, there’s the added complication of the bag’s color. The conductive carbon leaves the bag opaque, requiring the contents to be removed to be seen, leaving the potential for damage.

The biggest benefit of the Black Poly’s was some shielding at a lower price point. But in recent years, shielding bags have become much more affordable, and reputable vendors have effectively eliminated them from their inventory.

Shielding bags combine the antistatic and dissipative qualities of the poly bags with metal shielding and a polyester insulator (or dielectric) layer. Where Pink Poly’s stop about 10% and Black Poly’s 30%, Shielding Bags stop 97% of electrostatic pulses.

Shielding bags are classified in two ways:

Buried Metal (Metal-In)

Buried Metal bags consist of a dissipative poly layer, glued or laminated on top of a metallized polyester – usually aluminum, but sometimes nickel or copper – laid over an additional dielectric polyester layer.

The metal between two layers of plastic offers better protection than the alternative.

Surface Metal (Metal Out)

In Surface Metal bags, the layers are ordered differently, with the poly and the dielectric polyester glued together, then coated with a nickel sprayed with an abrasion resistance coating.

Unfortunately, the outside metal coating causes a faster dissipation of electrical charges, resulting in sparking issues similar to that of the Black Poly Bags, although not as dangerous.

Moisture Barrier Bags

For long term storage or moisture sensitive items, Moisture Barrier bags provide the ultimate protection. These bags are similar to, but stronger than normal shielding bags and provide an additional protection with a moisture vapor barrier.

There are two types of Moisture Barrier bags: Foil and Tyvek (utilizing the DuPont material) or Heavy Metallization. Both provide similar levels of protection, the difference primarily being the higher cost of the Tyvek structured bags.

Static protective bags should always be implemented as part of a more comprehensive static control environment, which should always include proper grounding tools. And while expenditures are always a factor, consider the insignificant price of proper protective measures when compared to the cost of replacing the delicate components inside the package.

Contact us today for more information; we would love to be your full service, seamless ESD solution provider.