ANSI/ESD S20.20

With electronic components getting smaller and more sensitive, it’s important to make sure they are protected from ESD events like static discharge. Per ANSI/ESD S20.20, “Protective packaging is required to store, transport, and protect ESDS electronic items during all phases of production.” Per the new 2018 requirements for ANSI/ESD S541, the shielding requirement was changed that remaining discharge for the bags should be less than 20 nanojules.

One of the more common used bags is a low charging Pink Poly bag. These bags are made from a tinted polyethylene material with an antistatic coating that can wear away. This turns the bag insulative over time, making it noncompliant to ANSI/ESD S541 recommendations. They also lack discharge shielding protection which makes components within the bag susceptible to ESD event damage. Metallized Shielding bags are constructed from a metalized polyester film and a low charging polyethylene laminate. This provides the bags with a shielding layer that creates a Faraday cage protecting the ESD sensitive components within the bag from possible ESD event damage. The low charging inner layer and outer layer of the bag prevent tribocharging from occurring, minimizing the build up of ESD charges when handling components.

Watch this video on Pink Poly vs Static Shielding Bag Testing and learn why Metallized Static Shielding Bags are the best packaging solution offering full protection against ESD events.

Pink Poly and Static Shielding Bag Testing

Purchase or Request a Sample at StaticControl.com

Welcome back to “A Minute with Miranda.” This week we will be covering how the EM Aware Monitor provides continuous monitoring to detect and measure ESD Events in your STM machine.

The SCS EM Aware Monitor is a continuous monitor for three key parameters that allow you to verify your ESD process in an automated insertion machine; ESD events, change in static voltage field, and ionizer balance. The thresholds for all three of these parameters are fully adjustable by the user. The EM Aware Monitor is a miniature radio receiver tuned to detect and measure the unique waveform generated by an ESD event. The EM Aware Monitor meets the Continuous Monitor requirements of ANSI/ESD S20.20 in accordance with ESD TR1.0-01 and ANSI/ESD STM3.1. It meets the recommendations of ESD Handbook ESD TR20.20 which includes “if the products that are being produced are of such value that the knowledge of a continuous, reliable ground is needed, then continuous monitoring should be considered or even required.”

View the full range of SCS EM Aware Monitors here

Welcome back to “A Minute with Miranda.” This week we will be covering how to properly clean an ESD Worksurface Mat.

For optimum electrical performance, the ESD worksurface mat surface should be cleaned regularly using a recommended ESD mat cleaner. Per the ESD Handbook ESD TR20.20, “Ensure that cleaners that are used do not leave an electrically insulative residue common with some household cleaners.”
We recommend using Reztore ESD Surface and Mat Cleaner. Reztore is alcohol free and does not contain silicone or other substances that will leave an insulative residue or inhibit the performance of the ESD worksurface mats.

After cleaning the ESD worksurface mat with Reztore it is recommended to test the surface to ensure that all insulative contaminates such as dirt and grime have been removed from the mat.
SCS worksurface mats meet the ANSI/ESD STM4.1 and ANSI/ESD S20.20 required limit of 1 x 106 to less than 1 x 109 ohms for Rtt and Rtg and the recommendations of ANSI/ESD S4.1. View the range of Reztore Alcohol Free products here.

Welcome back to “A Minute with Miranda.” This week we will be discussing how to test the point-to-point resistance (Rtt) and the resistance-to-ground (Rtg) of a Conductive ESD Floor.

ANSI/ESD S20.20 requires initial and periodic verification of an ESD Flooring System. ANSI/ESD STM7.1 outlines the test methods applicable for the Conductive flooring material. For the Point-to-Point resistance (Rtt) test the flooring will be tested with a resistance measurement meter and
2 x 5lbs cylindrical electrodes positioned 36” apart. The value for the test should be less than or equal to 1 x 106 ohms.

The Resistance Point-to-Ground (Rtg) test should be conducted with a resistance measurement meter and 1 x 5lbs cylindrical electrode. One lead from the meter should be connected to the ground point and the other lead will be connected to the electrode. The test value should be less than or equal to 1 x 106 ohms.

View the full range of SCS Surface Resistance Testers here.

Welcome back to “A Minute with Miranda.” This week we will be discussing how to test the point-to-point resistance (or Rpp) of an ESD Smock.

ANSI/ESD S20.20 requires initial and periodic verification of ESD Control items – this includes ESD Smocks. ANSI/ESD STM2.1 outlines the test method applicable for ESD Smocks: the ESD Smock is to be placed on an insulative surface and 2 x 5lbs cylindrical electrodes are to be positioned on each cuff before taking the measurement. The Resistance Point-to-Point Rpp of the groundable smock needs to be less than 1 x 109 ohms.

View the full range of SCS ESD Smocks here.

Welcome back to “A Minute with Miranda.” This week we will be covering how to properly wear a wrist strap.

ANSI/ESD S20.20 requires seated personnel to be connected to the grounding / equipotential bonding system via a wrist strap. The total resistance of the Wrist Strap System needs to be less than 3.5 x 10^7 ohms. The key to a wrist strap is the intimate contact of the band to the skin and that the coil cord is connected to ground. Wrist straps need to be tested at least daily before handling any ESD sensitive devices.

Operators can choose between elastic and metal wristbands. Elastic wristbands are comfortable to wear and easy to adjust. Metal wristbands generally last longer and are easier to clean. View the full range of SCS Wrist Straps here.

Welcome back to “A Minute with Miranda.” This week we will be covering how to perform the Rtt and Rtg test on an ESD Worksurface Mat.

Before using a worksurface mat in an EPA environment, you need to verify that the mat will meet the ANSI/ESD S20.20 Worksurface Requirements.
For both the Rtt and Rtg test the worksurface should test between 1 x 106 to less than 1 x 109 ohms. The test should be performed in accordance to the ANSI/ESD S4.1 Standards.

SCS worksurface mats meet the ANSI/ESD STM4.1 and ANSI/ESD S20.20 required limit of 1 x 10^6 to less than 1 x 10^9 ohms for Rtt and Rtg and the recommendations of ANSI/ESD S4.1.

View our complete SCS Static Worksurface mat offering here.

Welcome back to “A Minute with Miranda.” This week we will be covering how to launder your ESD Smocks.

SCS Static Control Smocks should be laundered periodically for proper operation. Smocks should be washed by hand or with a standard household washing machine using cold or warm water with a non-ionic liquid detergent. Avoid using bleach, fabric softeners or dry detergents as these can contaminate the conductive fibers and make the garment insulative .

After washing the smocks they should either be hung dry or tumbled dry at low heat. High heat can degrade the conductive fibers within the garment and degrade the ESD properties.

With normal wearing and washing conditions, SCS Static Control Smocks will maintain their ESD properties for a minimum of 100 washings.

SCS Smocks meet the requirement for Groundable Static Control Garment System per ANSI/ESD S20.20 required limit of less than 3.5 x 107 ohm Rtg tested per ANSI/ESD STM2.1 and ESD TR53.

To learn more about SCS Smocks, click here.

Welcome back to “A Minute with Miranda.” This week we will be covering ESD Worksurface Mats.

SCS worksurface mats serve two purposes for an ESD worksurface in an EPA:

  • they provide a surface that does not generate a static charge and
  • they remove charges from all charged conductors, which include ESD susceptible devices and assemblies, that are placed on the surface.

SCS worksurface mats are constructed from either dissipative 2 layer rubber or 3 layer vinyl material and are available in both rolls and mat kits.

We can also quote custom sizes SCS worksurface mats meet ANSI/ESD STM4.1 ANSI/ESD S20.20 required limit of 1 x 106 to less than 1 x 109 ohms for Rtt and Rtg and the recommendations of ANSI/ESD S4.1

For more information on SCS Worksurface matting, check out our Selection Guide here.

When referring to an “ESD Protected Area” or “EPA”, a lot of people imagine rooms or even whole factory floors with numerous workstations. This very common misconception leads to nervousness and even fear when it comes to implementing an ESD Control Program. There is a concern regarding the cost and time implications when establishing an EPA. However, most often, a simple ESD workstation is completely sufficient to fulfill a company’s needs to protect their ESD sensitive products. Today’s post will provide a step-by-step guide on:

  • How to create an EPA at an existing workstation,
  • What ESD control products are required
  • How to correctly set up ESD control products

What is an “ESD Protected Area” or “EPA”?

An EPA is an area that has been established to effectively control Electrostatic Discharge (ESD) and its purpose is therefore to avoid all problems resulting from ESD damage, e.g. catastrophic failures or latent defects. It is a defined space within which all surfaces, objects, people and ESD Sensitive Devices (ESDs) are kept at the same electrical potential. This is achieved by simply using only ‘groundable’ materials for covering of surfaces and for the manufacture of containers and tools. All surfaces, products and people are grounded to Ground.

What is Grounding?

Grounding means linking, usually through a resistance of between 1 and 10 megohms. Movable items (such as containers and tools) are grounded by virtue of lying on a grounded surface or being held by a grounded person. Everything that does not readily dissipate a charge must be excluded from the EPA.

How big does an EPA need to be?

An EPA can be just one workstation, or it could be a room containing several different workstations. “The definition of an EPA depends somewhat on the user environment. An EPA may be a permanent workstation within a room or an entire factory floor encompassing thousands of workstations. An EPA may also be portable as used in a field service situation.” [Handbook ESD TR20.20-2016 Clause 9.0 ESD Protected Areas]

What is needed to convert a Workstation into an EPA?

Creating an EPA at an existing workstation does not need to be complicated or expensive. There are just a few things that are required:

Workstation-Setup.png

1. Wrist Strap

Wrist straps are the most common personnel grounding devices and are used to link people to ground. They are required if the operator is sitting. A wrist strap is made up of two components:

  • A wristband that is worn comfortably around the wrist and
  • A coiled cord that connects the band to Ground or a Wrist Strap Grounding System as explained in #4.

2. Wrist Strap Grounding System

These have been designed to be installed underneath bench tops where they are easily accessible to operators and where they are unlikely to be knocked and damaged or hinder the operator. The grounding cord of the Grounding System needs to be connected to a suitable Ground.

3.Worksurface Mat

ESD protective worksurfaces aid in the prevention of damage to ESD sensitive items (ESDS) and assemblies from electrostatic discharge.

ESD worksurfaces, such as mats, are typically an integral part of the ESD workstation, particularly in areas where hand assembly occurs. The purpose of the ESD worksurface is two-fold:

  • To provide a surface with little to no charge on it.
  • To provide a surface that will remove ElectroStatic charges from conductors (including ESDs) that are placed on the surface.

4. Worksurface Mat Grounding Cord

An ESD worksurface needs to be grounded using a ground cord. A ground wire from the surface should connect to Ground. Best practice is that ground connections use firm fitting connecting devices such as metallic crimps, snaps and banana plugs to connect to designated ground points. The use of alligator clips is not recommended.

Where sitting personnel will be grounded via a wrist strap, this method is not feasible for operators moving around in an ESD Protected Area. In those situations, a flooring / footwear system is required.

5. Foot Grounders

Foot grounders are designed to reliably contact grounded ESD flooring and provide a continuous path-to-ground by removing electrostatic charges from personnel. They are easy to install and can be used on standard shoes by placing the grounding tab in the shoe under the foot.

Foot grounders must be worn on both feet to maintain the integrity of the body-to-ground connection Wearing a foot grounder on each foot ensures contact with Ground via the ESD floor even when one foot is lifted off the floor.

6. Floor Mat

Floor matting is an essential component in the flooring / footwear system when grounding moving or standing personnel. The path to Ground from operators via heel grounders to Ground is maintained by using dissipative or conductive flooring.

Floor mats don’t just ground personnel; they are also used to ground ESD control items (e.g. mobile carts or workstations).

7. Floor Mat Grounding Cord

Just like worksurface matting, floor matting needs to be connected to Ground. This ensures that any charges on the operator are dissipated through their heel grounders and the floor matting to Ground. A floor mat grounding cord is used to link the floor mat to Ground.

Alternatively, matting can be grounded via a strip of copper foil.

 

Installing an ESD Workstation

To install the ESD workstation, it is necessary to ground the worksurface and operator with the following steps:

1. Working-Surface-Mat.png Lay the worksurface mat flat on the workbench with the stud(s) facing upwards.
2. Working-Surface-Mat-Grounding-Cord.png Connect the worksurface mat grounding cord to the worksurface mat.
3. Wrist-Strap-Ground.png Connect the other end of the worksurface mat grounding cord to Ground.
4. Wristband.png Place the wristband on the wrist.
5. Coiled-Cord.png Connect the coiled cord to the wristband.
6. Grounding-System.png Attach the Wrist Strap Grounding System to the bench. Remember that it needs to be connected to a suitable Ground.
7. Wrist-Strap-Grounding-System.png Connect the other end of the coiled cord to the Wrist Strap Grounding System and verify personnel is properly grounded.

If your operators are standing or mobile and grounding via a wrist strap is not feasible, ground the worksurface, and the ESD flooring:

1. Working-Surface-Mat-Grounding-Cord.png Ground the worksurface mat by following steps #1 to #4 above
2. Floor-Mat.png Lay the floor mat flat on the floor with the stud(s) facing upwards.
3. Floor-Mat-Grounding-Cord.png Connect the floor mat grounding cord to the floor mat.
4. Wrist-Strap-Ground.png Connect the other end of the floor mat grounding cord to Ground.
5. Foot-Grounders.png Place the foot grounders on the feet and verify personnel is properly grounded.

 

Conclusion

An EPA can be created at an existing workstation in a facility. To establish an EPA it is important to:

  • Ground all conductors (including people),
  • Remove all insulators (or substituting with ESD protective versions) or
  • Neutralize process essential insulators with an ionizer.

With a few simple steps, you can convert your existing workstation into an ESD workstation. You will need:

  • Worksurface Mat
  • Worksurface Mat Grounding Cord
  • Wrist Strap
  • Wrist Strap Grounding System

Optional:

  • Foot Grounders
  • Floor Mat
  • Floor Mat Grounding Cord

We hope this article has introduced the basics of an ESD Protected Area (EPA), and the steps needed to create an ESD Workstation.

For more information on how to get your ESD control program off the ground, Request a free ESD/EOS Assessment at your facility by one of our knowledgeable local representatives to evaluate your ESD program and answer any ESD questions!