In This Article
This article contains:
- Understanding the Science Behind ESD Events
- Protecting Sensitive Electronics During Shipping
- Taking a Defense-in-Depth Approach to ESD
- Verifying the Effectiveness of Static Shielding
- Moving From Commercial to Mil-Spec Packaging
- Frequently Asked Questions About ESD Protection
Electrostatic discharge (ESD) is the invisible killer of electronics. A single ESD event can render even the most expensive devices inoperable, resulting in costly returns and warranty claims. You know it’s a problem, but do you know how to prevent electrostatic discharge to protect sensitive electronics during shipping and handling?
Understanding the Science Behind ESD Events
When two objects with different electrical potentials come into contact or close proximity, ESD rapidly transfers an electrostatic charge. This sudden flow of static electricity can cause considerable damage to sensitive hardware, potentially rendering the device inoperable. Everyday events — such as handling plastic packaging — can silently damage devices.
Materials can be conductive, insulative or dissipative, meaning they either resist or conduct electrical charges. Those that resist the flow hold a static charge, making them highly susceptible to ESD events. One example is plastics, which can’t neutralize or ground charges.
Aside from material choice, size can also make objects susceptible to ESD damage. As electrical devices become smaller, the risks grow. Modern electronics are highly sensitive because they are engineered with nanoscale elements, which exacerbates risks.
Circuit boards often comprise thousands of tiny electronic connections — and each one is susceptible to the effects of ESD. Even low-voltage events can cause permanent damage, rendering critical components inoperable.
Catastrophic failure is immediately recognizable because the device ceases to function. Items with latent damage may pass initial testing but fail during operation. It damages your brand reputation more than a dead-on-arrival item would because it makes your products seem low-quality and causes unplanned downtime for your customers.
Protecting Sensitive Electronics During Shipping
Unless you prevent electrostatic discharge, you will deal with a high volume of returns and warranty claims. Frustrated customers may switch to your competitors and leave negative reviews, costing you business. The issue is that ESD can occur after the sale.
While you manage the static on your assembly line, you can’t control the friction in a delivery truck or the humidity in a cargo hold. Even if electronics leave your facility fully operational, a single static shock can damage sensitive components during transit — and you may not find out for weeks or months, in the case of latent damage.
The Cause of In-Transit ESD Events
The triboelectric effect is a type of contact electrification where items become electrically charged after coming into contact with each other and then separating. An electric charge transfers between them, leaving one positively charged and the other negatively charged. It is a common cause of static electricity.
Trucks in transit generate mechanical vibration, which creates friction, thereby triggering the triboelectric effect. Think of it as friction-induced charging. This buildup can occur both inside and outside boxes, posing a risk to hardware.
According to the Institute of Electrical and Electronics Engineers, a discharge of as little as 100 volts (V) can degrade sensitive parts designed to operate at voltages as low as 1.2 V. The cost to replace damaged components ranges from a few cents to thousands of dollars, depending on the extent and location of the damage.
The first step in preventing electrostatic discharge is identifying susceptible components in the products you manufacture and ship. Their ESD protection level is the voltage classification they can withstand, which depends on their ability to dissipate static electricity.
Taking a Defense-in-Depth Approach to ESD
A defense-in-depth approach is the most effective way to mitigate static damage during shipping and handling. The idea is to protect a system against any particular attack using multiple independent techniques.
Antistatic measures are not sufficient to protect sensitive electronics during shipping, as they only prevent the buildup of static electricity. Material won’t hold or generate a triboelectric charge, stopping it from introducing static into sensitive environments. However, it does not protect against ESD itself.
In addition to preventing the buildup of static electricity, static shielding also defends against ESD both inside and outside of the bag. Static shield bags protect electronics from electrostatic discharge, thereby mitigating product losses. However, even this measure alone is not enough to offer comprehensive protection.
Low humidity — which is common in air freight — increases static generation. Dry air is harder to keep static-free. However, you know full well how damaging moisture can be to electronics. High humidity causes corrosion. A more subtle but equally destructive outcome is electromigration. When moisture is present, an electric field can cause a short circuit.
There is no magic threshold at which you eliminate static potential entirely, so increasing the relative humidity has diminishing returns. You must use moisture barrier bags, which are opaque and aluminized, that combine shielding and moisture protection.
Verifying the Effectiveness of Static Shielding
Even with desiccants and static-shield bags, there is still a slight chance that something goes wrong in transit and causes damage. Maybe the truck’s climate control system fails to absorb the moisture in the air, or cargo suddenly enters a warmer area, causing condensation to form.
ESD events are responsible for an estimated $5 billion in annual losses in the electronics industry. They cause approximately 33% of device failures, with approximately 60% to 90% stemming from latent defects. If there were a single solution that worked 100% of the time, none of these figures would be this high.
Whatever the source, damage is likely. To ensure your defenses adequately prevent electrostatic discharge and corrosion, you should insert humidity indicator cards within the bags. They monitor the relative humidity level inside sealed, moisture-sensitive containers, providing passive recordkeeping during transit.
These cards use moisture-sensitive chemicals to record relative humidity. Each color-changing spot corresponds to a relative humidity level, such as 30%, 40% or 50%. If the spots change color, the receiving engineer knows to replace the saturated desiccant with a new packet or examine the item for damage. It provides immediate visual proof of package integrity.
Moving From Commercial to Mil-Spec Packaging
The American National Standards Institute (ANSI) developed the ANSI/ESD standards as a guideline to help you protect sensitive electronic components from sudden static discharges. It mandates ESD-safe manufacturing, assembly and packaging.
Adopting these ESD control measures would help you protect sensitive electronics during shipping and handling. However, meeting the absolute minimum requirements may be insufficient to safeguard modern, highly sensitive hardware. More lenient standards may seem cost-effective, but you pay for up-front cost savings when you have to replace damaged parts.
Military specification (MIL-SPEC) packaging offers the maximum protection against moisture and static, even in extreme environments. The United States Department of Defense developed MIL-STD-2073 and Method 50, so you can trust in their effectiveness.
Method 50 is a military standard for dry packing. It requires a water- and vapor-proof barrier, desiccant and humidity indicator card, providing maximum protection for moisture-sensitive devices. It is becoming increasingly common in commercial sectors like consumer electronics.
Method 50 shipping labels indicate a package’s contents comply with Method 50 standards for water- and vapor-proof protection. They ensure proper handling by warning personnel not to open packages that contain desiccants until the item is delivered or requires inspection.
Worker in protective gloves placing green printed circuit board into cardboard tray for safe storage and shipping in electronics plant
Frequently Asked Questions About ESD Protection
These frequently asked questions about ESD protection techniques will help answer any of your remaining questions.
How can you tell if an item is ESD susceptible?
You can use technical sheets, specifications and material type to identify items that may be vulnerable to static electricity. The most common classification type for quantifying a device’s susceptibility is the human body model, which simulates a person becoming charged and discharging through their finger to the device.
The charged device model simulates a charged component discharging to a grounded surface. This type of ESD event is more common in automated assembly. You can decide which best suits your needs by evaluating the level of human involvement in your manufacturing and assembly processes.
How do you prevent latent ESD failures?
Preventing electrostatic discharge is a complex, in-depth process. Testing can help you identify the voltage your products can withstand. You should use this knowledge to design products as ESD-safe as possible. Also, use antistatic workstations, maintain an optimal indoor relative humidity level and use static shield bags with desiccants.
How far is too far regarding ESD protection?
Remember, ESD causes billions of dollars in losses annually in the electronics industry alone. It has been nicknamed “the invisible killer” because it is very difficult to detect. There is no such thing as “too far” in this context — you must use comprehensive protection measures.
As the leading supplier of MIL-SPEC packaging, Edco Supply Corporation can deliver precisely that. Every MIL-SPEC order ships with a certificate of compliance to meet DoD requirements. It can manufacture custom bags in short and large runs, with a turnaround time as fast as two days. It also supplies moisture barriers, humidity indicator cards and packaging labels.
Packaging Is the Final Element of Product Design
As devices get smaller and more complex, preventing electrostatic discharge becomes increasingly challenging. This poses a significant issue, as high-reliability parts must function reliably for years. If they suddenly and unexpectedly fail, your customers will want answers — and refunds.
You can make your manufacturing and assembly practices as ESD-safe as possible, but once products leave your facility, they become susceptible to the triboelectric effect. Proper packaging is essential for protecting sensitive electronics during shipping. It is not just trash to be thrown away — it is the final element of product design.
