Category Archives: Meters and Measurement

Controlling Static Charge Generation with ESD Flooring

Static discharges can be noticed when you touch an object of different electrical potential such as a door knob, and a bolt of electricity flows from your charged body to the door knob. This flow of electricity is actually a result of the stored static charge that is being rapidly transferred to the knob. This discharge that can be felt as well as seen, is commonly referred to as an electrostatic discharge, or “ESD”.
The generated static charges are a potentially costly occurrence for office and factory employers. You will learn in today’s post how they can easily be controlled with different types of floor material.

Static Charge Generation from Flooring
When a person walks across a floor, a triboelectric charge builds up in the body due to the friction between the shoes and floor material. The simple separation of two surfaces (such as a person walking across a floor with soles contracting and separating from the floor) can cause a transfer of electrons resulting in one surface being positively and the other one negatively charged, resulting in static charges.

Generating Charges by walking across a CarpetGenerating Charges by walking across carpet

It is not necessarily the static charge generated in the body that does the damage as much as it is the difference in potential that creates an electrostatic discharge.

The problem with ESD
The generation of a static charge can pose quite a problem for environments that contain sensitive equipment or components that are vulnerable to static damage, such as electronics manufacturing, repair facilities and medical facilities, including computer rooms and clean rooms.
Controlling the damage and costs caused by ESD is usually the main concern that drives a company to implement a static control programme. The costs involved with static damage not only include the immediate cost of the damaged component, but the contributing cost of diagnostic, repair and labour that is needed to replace or fix the component. In many cases the labour involved can far exceed the component cost.

Flooring Materials
There are several options available on the market ranging from coatings (floor finish or paint) to coverings (vinyl or rubber). The choice of material depends on the mechanical and optical properties required as well as the available budget.
In general, floor coverings will last longer (10 years or more) than a floor coating. They are more durable and have a specific resistance to ground that remains constant over time.

Types of Floor Coverings – click here for more information

Coatings are easier to apply and repair and their initial cost is considerably lower. Coatings are usually applied to existing floors and often serve to convert a conventional floor into an ESD floor. However, regular maintenance is required as coatings will lose their ESD properties over time.

1. Floor Coatings

  • Antistatic Coating:
    Conventional carpets can be treated with an Antistatic Coating or other treatment. It is required that the treatment be replenished on the carpet as it wears away due to foot traffic.
    ESD carpet is available but proper maintenance is very important.
  • ESD Floor Finish:
    Existing hard surfaces (e.g. concrete, sealed or painted wood, linoleum, asphalt) can be treated with ESD Floor Finish to eliminate the need for ESD control flooring. Repeat applications are required periodically to keep ESD properties within specification.
  • ESD Paint:
    Paint is ideal for providing a cost effective static-free environment and is very effective as a static control floor coating for electronics manufacturing, assembly and storage. It controls dissipation of static electricity and provides path to ground.

2. Floor Coverings:
Floor coverings will have either “conductive” or “dissipative” electrical properties:

  • Conductive materials have a resistance to ground (RG) of greater than 1 x 103 ohms but less than 1 x 105
  • Dissipative materials have a resistance to ground (RG) of greater than 1 x 105 ohms but less than 1 x 1012

It is recommended to use conductive flooring material; EN 61340-5-1 requires ESD flooring to be less than 1 x 109 ohms (RG). The same standard requires a person/footwear/flooring to be less than 3.5 x 107 ohms (resistance in series of operator plus footwear plus floor). Remember that floors get dirty which can raise floor resistance. Therefore, it is good to start off with a floor that is conductive (less than 1 x 106 ohms). So even if the resistance increases, you’re within the required limits of the ESD Standard.

  • Carpet:
    ESD control carpets are made with static dissipative yarn and only require that the yarn be kept clean and free of insulative dirt, dust and spray cleaners.
  • Matting:
    Types of matting range from vinyl to rubber and anti-fatigue matting.
    Vinyl is generally cheaper and provides high resistance to many chemicals. Rubber on the other hand is more durable and can withstand extreme hot and cold temperatures. Anti-fatigue matting (AFM Series) is designed to provide comfort for personnel that must stand or walk for long periods.

Considerations when using Flooring Materials
1. Grounding
EN 61340-5-1 requires that all conductors in an ESD protected area, including personnel, must be grounded. This includes ESD flooring; it must be electrically connected and attached to a known ground. The Desco Europe floor mat ground cord 231265 is just one option for grounding floor matting.

2. Periodic Verification
All ESD control items (including ESD flooring) have to be tested:

  • Prior to installation to qualify product for listing in user’s ESD control plan.
  • During initial installation.
  • For periodic checks of installed products as part of EN 61340-5-1 clause 5.2.4 Compliance verification plan.

19290_RtgMeasuring Surface Resistance of ESD Floor Matting – click here for more information

A surface resistance meter can be used to verify compliance of the ESD floor with the ESD standard.

3. Person/Footwear/Flooring System
ESD flooring does not ensure protection from ESD damage unless operators walking across the ESD floor wear ESD footwear, either ESD shoes or ESD foot grounders.
ESD 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. This will more reliably remove static charges generated by human movement.
Desco Europe offer a number of different foot grounder types for your requirements.

Conclusion
Static charges can easily be controlled with different types of floor material which vary in their properties, cost and durability. The best static control systems are not only the ones that protect sensitive components and equipment but are: A) at hand and readily available, B) easily maintained. Floor coverings are long lasting and maintain their ESD properties over time, while existing floors can be economically converted for use in an ESD control program using various types of coatings.
Remember that all ESD control items such as flooring, personnel grounding and specialty equipment should be grounded and tested periodically to verify all components are within specification.

Not sure which ESD flooring is right for you? Request a free ESD Survey at your facility by one of our knowledgeable representatives to evaluate your ESD programme and answer any ESD questions!

 

 

 

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How to measure the effectiveness of your ESD Control Programme

Introduction
It is now well established that electronic devices and systems can be damaged by exposure to high electric fields as well as by direct electrostatic discharges. While good circuit layout and on-board protection may reduce the risk of damage by such events, the only safe action at present is to ensure that devices are not exposed to levels of static electricity above the critical threshold.
This can only be achieved by introducing a static control programme which usually involves setting up an ESD Protected Area (EPA) in which personnel are correctly grounded and all materials e. g. flooring, bench tops etc. meet the of the ESD Standard. However, setting up an EPA does not of itself guarantee a low static environment. Production procedures may change, new materials may be introduced, the performance of older materials may degrade and so on.
To ensure the effectiveness of any static control programme it is important that regular measurements are carried out:

  • to determine the sensitivity to ESD of devices being produced or handled.
  • to confirm that static levels are lower than the critical level, and that new or modified work practices have not introduced high static levels.
  • to ensure that both new and existing materials in the EPA meet the necessary requirements.

Only after an ‘operational baseline’ has been established by regular auditing will it become possible to identify the origin of unexpected problems arising from the presence of static.

1. Determining the sensitivity of ESDs
The bottom line is: you need to know what you’re dealing with before you can create an action plan. Only once you know the sensitivity of the items you are handling, can you work towards ensuring you’re not exceeding those levels.
Part of every ESD control plan is to identify items in your company that are sensitive to ESD. At the same time, you need to recognize the level of their sensitivity. As explained by the ESD Association, how susceptible to ESD a product is depends on the item’s ability to either:

  • dissipate the discharge energy or
  • withstand the levels of current.

For further information, check out this post.

2. Measurements to prove the effectiveness of an ESD Control Programme
Measuring electrostatic quantities poses rather special problems because electrostatic systems are generally characterised by high resistances and small amounts of electrical charge; the latter being true despite the dramatic effects often associated with static. Consequently, conventional electronic instrumentation cannot normally be used.

Electrical Field
Wherever electrostatic charges accumulate, they can be detected by the presence of an associated electric field. The magnitude of this field is determined by many factors, e. g. the magnitude and distribution of the charge, the geometry and location of grounded surfaces and also the medium in which the charge is located.
The current general view of experts is that the main source of ESD risk may occur where ESDS can reach high induced voltage due to external fields from the clothing, and subsequently experience a field induced CDM type discharge.” [CLC TR 61340-5-2 User guide Garments clause 4.7.7.1 Introductory remarks]

50597_Use2Using a Digital Static Field Meter to test static fields

A static field meter is often used for ESD testing of static fields. It indicates surface voltage and polarity on objects and is therefore an effective problem solving tool used to identify items that are able to be charged.

A field meter can be used to:

  • verify that automated processes (like auto insertion, tape and reel, etc) are not generating charges above acceptable limits.
  • measure charges generated by causing contact and separation with other materials.
  • demonstrate shielding by measuring a charged object and then covering the charged item with an ESD lab coat or shielding bag. Being shielded the measured charge should be greatly reduced.

ESD Events
ESD events can damage ESD sensitive items and can cause tool lock-ups, erratic behaviour and parametric errors. An ESD Event Detector like the SCS EM Eye will help detect most ESD events. It detects the magnitude of events and using filters built into the unit, it can provide approximate values for some ESD events for models (CDM, MM, HBM) using proprietary algorithms.

CTM048-21_Use2Using the SCS EM Eye ESD Event Meter to detect ESD Events

Solving ESD problems requires data. A tool counting ESD events will help carry out a before-and-after analysis and will prove the effectiveness of implementing ESD control measures.

3. Checking materials in your EPA
When talking about material properties, the measurement you will most frequently come across is “Surface Resistance”. It expresses the ability of a material to conduct electricity. It is therefore related to current and voltage. In fact, the surface resistance of a material is the ratio of the voltage and current that’s flowing between two pre-defined electrodes.
It is important to remember that the surface resistance of a material is dependent on the electrodes used (shape as well as distance). If your company implements an ESD control programme compliant to the ESD Standard EN 61340-5-1, it is therefore vital to carry out surface resistance measurements as described in the Standard itself. For more information on the definition of resistance measurements used in ESD control, check out this post.
A company’s compliance verification plan should include periodic checks of surfaces measuring:

  • Resistance Point-to-Point (Rp-p) and
  • Resistance-to-ground (Rg).

222643UseMeasuring Surface Resistance of worksurface matting using a Digital Surface Resistance Meter Kit

Surface resistance testers can be used to perform these tests in accordance with EN 61340-5-1 and its test method IEC 61340-2-3; if these measurements are within acceptable ranges, the surface and its connections are good. For more information on checking your ESD control products, catch-up with this and this post. This 2-part series goes into depth as to what products you should be checking in your EPA and how they should be checked.

Conclusion
Measurements should form an integral part of any ESD control programme. High quality instruments are available commercially for measuring all the parameters necessary for quantifying the extent of a static problem. We hope the list above has provided an introduction to the techniques most commonly used.

HBM vs. CDM

As previously explained, an Electrostatic Discharge is a rapid, spontaneous transfer of an electrostatic charge induced by a high electrostatic field through a spark between two bodies at different electrostatic potentials as they approach or are separated from one another.
The ESD Association characterises three models of discharge, Human Body Model (HBM), Charged Device Model (CDM) and Machine Model (MM). Each model is intended to follow specific discharge properties such as the rise and fall times of the discharge current waveform.

Today, we will discuss HBM and CDM.

Human Body Model (HBM) simulates a person becoming charged and discharging from a bare finger to ground through the circuit under test. Humans are considered a primary source of ESD and HBM can be used to describe an ESD event due to the combination of the capacitance of a human body and resistance of skin touching a sensitive component. Typically, you need to pay better attention to personnel grounding to eliminate HBM.

Per ESD Handbook ESD TR20.20-2016 section 3.4.1 Human Body Model (HBM): “HBM has been in use for over 100 years. It was first defined to allow measurement and evaluation of explosion hazards for underground mining operations. There are a few different test standards describing the HBM for military and commercial applications, but the differences are in the application of the test, calibration of the system, and other ancillary items. The waveform, as defined by the human body resistance and capacitance, is virtually identical among all the test standards. The most widely used standard is ANSI/ESDA/JEDEC JS-001. The HBM test standard uses a stressing circuit which charges a 100 pF capacitor to a known voltage and discharges through a 1500-ohm resistor as shown in Figure 3. The simulators are verified by measuring various features of the current waveform, some of which are shown in Figure 4. Full details for tester qualification and waveform verification are described in ANSI/ESDA/JEDEC JS-001.

50528inuseAn operator handling an ESD sensitive device

Charged Device Model (CDM) simulates an integrated circuit becoming charged and discharging to a grounded metal surface. CDM can be used to describe an ESD event due to an integrated circuit that is suspended on a vacuum pick and then placed on a metal surface during assembly.
Manual operation and handling is much less likely these days as operations have become more automated. CDM is the most pragmatic discharge model in automated production today. Anytime a sensitive device is lifted from a tray and transported it is most likely generating a charge.

Per ESD Handbook ESD TR20.20-2016 section 3.4.2 Charged Device Model (CDM): “In principle, there are two variations of CDM. The first considers the situation of a device that is charged (through tribocharging) on its package, lead frame, or other conductive paths followed by a rapid discharge to ground through one pin or connector. The second considers the situation of a device which is placed in an electric field due to the presence of a charged object near the device. The device’s electrostatic potential is increased by this field. This process is sometimes referred to as static induction. The device will discharge if it is grounded while still in the electric field. In both cases, the device will discharge, the failure mode will be the same, and the failure type and location will be the same. The most widely used CDM standards use the static induction approach. In CDM simulators, the device is grounded by a pogo pin contacting one pin or lead of the device. The current through the pogo pin can be measured and recorded which is particularly important as the discharge current determines the ESD threshold, a schematic of this is shown in Figure 5.
Experimental results show that the CDM discharge current is very fast, with rise-times measured often below 100 ps with a “pulse width” (full width half-maximum [FWHM]) of less than 500 ps to1 ns, an example waveform with the key parameters is shown in Figure 6. By comparison, the HBM discharge has a typical rise-time of 2 to 10 ns and durations of hundreds of ns. Until 2014, the most commonly used CDM standards were JEDEC JESD22-C101 or ANSI/ESD STM5.3.1. These have now been superseded by ANSI/ESDA/JEDEC JS-002.

So, why does it matter?
Different types of discharge can affect devices in different ways. HBM is a somewhat slow discharge and ranges from 10 to 30 nanoseconds. CDM is a very fast discharge which in turn means the energy has no time to dissipate. The CDM-type damage threshold is often 10 to 20 times lower than the one for an HBM-type discharge. If an HBM-type discharge causes damage at 2000V, it is not uncommon to have the same component damaged by a 100 to 150V CDM event.

Per ESD Handbook ESD TR20.20-2016 section 3.2.1: “ESD threats in Electronic Production Lines ESD threats in electronics manufacturing can be classified into three major categories: 

  • Charged personnel – When one walks across a floor a static charge accumulates on the body. Simple contact of a finger to a device lead of a sensitive device or assembly which is on a different potential, e.g., grounded, allows the rapid transfer of charge to the device.
  • Charged (floating) conductor – If conductive elements of production equipment are not reliably connected to ground, these elements may be charged due to triboelectric charging or induction. Then these conductive elements may transfer charge to a device or assembly which is at a different potential.
  • Charged device/boards – During handling, devices or boards can acquire a static charge through triboelectric charging or can acquire an elevated electrostatic potential in the field of nearby charged objects. In these conditions, contact with ground or another conducting object at a different electrostatic potential will produce a very fast ESD transient.

This categorization is useful in that each category implies a set of ESD controls to be applied in the workplace. ESD threats from personnel are minimized by grounding personnel through the use of wrist straps and/or footwear/flooring systems. Discharges from conductive objects are avoided by assuring that all conductive parts that might contact devices are adequately and reliably grounded. The occurrence of ESD involving charged devices or boards is minimized by a) preventing charge generation (low-charging materials, ionization) or b) by providing low-current “soft landings” using dissipative materials.
Since these preventive measures are seldom perfectly deployed, the overall threat of ESD failure remains and the risk ultimately depends on how well the controls are maintained and the relative sensitivities of the devices being handled.”

Taking Action
Desco Europe recommends reviewing your manufacturing process and determining what model is the most relevant for your facility. Are your components handled directly by hand or by a hand tool such as tweezers or a vacuum pick?
Finding the root cause of ESD events is crucial to solving the problem. Desco Europe technology can identify events in areas like SMT line, soldering, printer and repair stations. Desco Europe has instrumentation to identify component sensitivity and measure ESD events as well as ensure compliance within your facility:

  • The SCS CTM082 ESD Pro Event Indicator has a special CDM filter switch to filter and reject EMI signals that are not caused by CDM discharges. Make sure to set requirements for static voltage and discharge strength within your production environment based on the most sensitive component in production.
  • The SCS CTM048-21 EM Eye ESD Event Meter will calculate the event magnitude for HBM and CDM. It also logs the events to a microSD card so they can be downloaded to a PC. Solving ESD problems requires data; a before-and-after analysis of data may now be measured and used to tailor your ESD control program.
  • The SCS 770063 EM Aware Monitor is ideal for automated equipment and will provide an approximate voltage for the ESD event based on HBM and CDM models. The EM Aware Monitor has Ethernet network connectivity and communicates with our Static Management Program (SMP). All activity is stored into a database for on-going quality control purposes. SMP allows you to pinpoint areas of concern and prevent ESD events. Quantifiable data allows you to see trends, become more proactive and prove the efficiency of your ESD process control system.

Checking your ESD Control Products – Part 2

Today’s post concludes our 2-part series on periodic verifcation. If you have missed the first part, you can catch-up on it here. As a reminder, it is recommended to regularely check all ESD Protected Area (EPA) products to ensure they are working correctly. After covering working surface matting and wrist straps in last week’s post, we’ll jump right in to discuss the remaining components in your EPA.

Floor Matting
A flooring / footwear system is an alternative for personnel grounding for standing or mobile workers. Foot grounders quickly and effectively drain the static charges which collect on personnel during normal, everyday activities. Foot grounders should be used in conjunction with floor surfaces which have a surface resistance of less than 1010 ohms.
As ESD floors get dirty, their resistance increases. For optimum electrical performance, floor matting must be cleaned regularly using an ESD mat cleaner, such as Reztore™ Surface & Mat Cleaner. Do not use cleaners with silicone as silicone build-up will create an insulative film on the surface.
Dissipative floor finish can be used to reduce floor resistance. Periodic verification will identify how often the floor finish needs to be applied. As the layer(s) of dissipative floor finish wear, the resistance measurements will increase. So, after some amount of data collection, a cost effective maintenance schedule can be established.

Testing floor mattingTesting floor matting

Floor matting can be checked using a resistance meter. Surface resistance meters are designed to measure resistance point-to-point (Rp-p) or surface to ground (Rg) in accordance with EN 61340-5-1 Electrostatics and its test method IEC 61340-2-3.

Footwear
ESD Shoes or Foot Grounders play an essential part in the flooring/footwear system. For more information on how to ground moving personnel effectively, check this post.
Before handling ESD sensitive devices, visually inspect your ESD footwear for any damage. Just like wrist straps, footwear should be checked while being worn using a wrist strap/footwear tester.

Checking foot groundersChecking foot grounders using 222567

Records of each test should be kept. Analysis and corrective action should take place when a footwear tester indicates a failure. Footwear needs to be checked daily.

ESD Packaging
Re-using shielding bags is acceptable as long as there is no damage to the shielding layer. Shielding bags with holes, tears or excessive wrinkles should be discarded.

Using ESD shielding bagsMake sure your ESD shielding bags are un-damaged

It is up to the user to determine if a shielding bag is suitable for re-use or not. The testing of every bag before re-use is not practical. Many companies will discard the shielding bag once used and replace it with a new one. Others will use a system of labels to identify when the bag has gone through five handling cycles:

  • Non-reusable labels are used that require the label be broken to open the bag.
  • The bag is then resealed with a new label.
  • When there are five broken labels, the bag is discarded.

The same principle applies to other ESD packaging, e.g. component shippers.

Ionisers
Ionisers are intended to neutralise static charges on insulators thereby reducing their potential to cause ESD damage. However, poorly maintained ionisers with dirty emitter pins and out-of-balance ionisers can put a charge on ungrounded items.
Remember to clean ioniser emitter pins and filters regularly. You can now even purchase ionisers that will alarm when emitter pins need to be cleaned or the ioniser is out of balance.

Checking ionisersChecking ionisers using 50598

The EMIT Ionisation Test Kit 50598 allows the Digital Static Field Meter 50597 to be used to measure the offset voltage (balance) and charge decay of ionisation equipment. The Test Kit also includes a Charger used to place a ±1000V charge on the 50567 Conductive Plate, making it possible to measure the discharge times of air ionisation equipment per ANSI/ESD SP3.3 Periodic Verification of Air Ionizers.

Wrist Strap/Footwear and Resistance Testers etc.
So you check your wrist straps and/or footwear and bench and/or floor matting regularly. But have you remembered the testers themselves? What good do all the checks do, if the testers you use are out-of-spec and show you incorrect results?
Yearly calibration is recommended – many manufacturers offer a calibration service or alternatively you can purchase calibration units from them and perform the calibration yourself.

 

So there you have it – a list of the most commonly used products in your ESD Protected Area (EPA) that you should check on a regular basis.
Questions for you: Do you have a verfication plan in place? If so, how often do you check your ESD protection products?

Checking your ESD Control Products – Part 1

Today we want to talk about a subject many users forget about when it comes to ESD protection: periodic verification.
Whilst many people understand the basic concepts of ESD and as a result insist on a properly equipped ESD Protected Area (EPA), they then forget all about it. They use the same products day-in, day-out, year after year, without knowing if their products are actually still working properly.
So today we want to look at the most common products in your EPA that you should be checking on a regular basis. And because there are quite a few product groups to discuss, we have split this post in 2 parts – we don’t want to scare you away with a never-ending blog post…

Why periodic verification?
Each component in an ESD protected area (EPA) plays a vital part in the fight against electrostatic discharge (ESD). If just one component is not performing correctly, you could damage your ESD sensitive devices potentially costing your company money. The problem with many ESD protection products (think wrist straps!) is that you can’t always see the damage. Just by looking at a coiled cord that has no visibly damage to the insulation you would not know if the conductor on the inside is damaged. That’s where periodic verification comes into play.
ESD protected area (EPA) products should be tested:

  1. Prior to installation to qualify product for listing in user’s ESD control plan.
  2. During initial installation.
  3. For periodic checks of installed products as part of IEC 61340-5-1 Edition 1 2007-08 clause 5.2.3 Compliance verification plan.

It’s #3 we will be focusing on in this 2-part series.

Worksurface Matting
The purpose of ESD bench matting is to ensure that when charged conductors (conductive or dissipative) are placed upon the surface, a controlled discharge occurs and electrostatic charges are removed to ground. However, this only occurs if the ESD work surface is actually connected to ground. If the matting is out-of-spec, not grounded at all, the stud on the mat has become loose or the ground cord has become disconnected, charges cannot be removed.
Many companies use a daily checklist, which includes the operator having to verify that ground cords are firmly connected.
Remember to regularly clean your bench matting to maintain proper electrical function (e.g. Reztore Surface and Mat Cleaner). Do not use cleaners with silicone as silicone build-up will create an insulative film on the surface.
The company’s compliance verification plan should also include periodic checks of work surfaces measuring:

  • Resistance Point-to-Point (Rp-p) and
  • Resistance-to-ground (Rg).

222643UseTesting a working surface using 222643

Surface resistance testers can be used to perform these tests in accordance with EN 61340-5-1 Electrostatics and its test method IEC 61340-2-3; if these measurements are within acceptable ranges, the worksurface matting and its connections are good.

Wrist Straps
As discharges from people handling ESD sensitive devices cause significant ESD damage, the wrist strap is considered the first line of ESD control.
Before handling ESD sensitive items, you should visually inspect the wrist strap to see if there are any breakages etc. The wrist strap should then be tested while worn using a wrist strap tester. This ensures all three components are checked: the wrist band, the ground cord (including resistor) and the interface with the wearer’s skin. Records of each test should be kept. Wiggling the resistor strain relief portion of the coil cord during the test will help identify failures sooner. Analysis and corrective action should take place when a wrist strap tester indicates a failure.

222566useChecking wrist straps using 222566

It is recommended that wrist straps are checked at least daily. An even better solution to daily wrist strap checks is the use of continuous monitors. They will alarm if the person or work surface is not properly grounded.

A note on worksurface matting and wrist straps: if you are using earth bonding points, earth bonding bars etc. to ground the operator and/or bench matting, remember to inspect and test those regularly as well (every 6 months for example).

Make sure you read the follow-up post here.

 

 

How do you know your ESD Flooring is working?

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

ESD protected area products should be tested:

  1. Prior to installation to qualify product for listing in user’s ESD control plan.
  2. During initial installation.
  3. For periodic checks of installed products as part of IEC 61340-5-1 Edition 1 2007-08 clause 5.2.3 Compliance verification plan.

TestRTTUSETesting the flooring in an ESD protected area

When floors get dirty, their floor resistance can increase. Therefore it is recommended to check ESD flooring regularly using a resistance checker. Vermason Surface Resistance Meters are designed to measure resistance point-to-point (Rp-p) or surface to ground (Rg) in accordance with EN 61340-5-1 Electrostatics and its test method IEC 61340-2-3.

Overview of available Surface Resistance Testers from Vermason:

 

Vermason’s Statfree T2 Mats Outlast the Competition

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The authors of a recent article in InCompliance Magazine titled Early Life Failure of Dissipative Workstation Mats have confirmed that Vermason’s Statfree™ T2 was the top performing worksurface mat (Mat ID#4 in the article) in their study. To read the rest of the article click HERE.

T2MattingVermason T2 Mats

Part of any good ESD Control Programme is periodic verification of the specifications of products being used for the ESD Control Plan. The most obvious example of periodic testing is when operators test their foot grounders or wrist straps before entering an ESD Protected Area. The ESD Association’s ESD TR53-01-15 Compliance Verification of ESD Protective Equipment and Materials describes the test methods and instrumentation that can be used to periodically verify the performance of ESD protective equipment and materials. Plexus Manufacturing Solutions in Neenah, WI noticed during periodic verification of their workstation mats, that the mats were drifting out of spec and wanted to determine what was causing the mats to fail. Through their in-house tests, they concluded that:

  • A solid ESD control programme including compliance verification periodic testing with data collection provides valuable and useful information.
  • Factory fluorescent lighting, likely from ultraviolet (UV) radiation, can have a measurable effect on the electrical properties of ESD dissipative mats over time.
  • Different mats tolerate or resist the effects of factory fluorescent lighting.
  • Since this experiment did not take into account lot-to-lot variation at the supplier for each mat P/N, future mats purchased will require lot traceability information to be stamped on the bottom of the roll, every 0.9m minimum.
  • The ESD Association technical report ESD TR4.0-01-02 Worksurfaces and Grounding Survey should consider adding ultraviolet light resistance as a property to consider in the Worksurface Selection Guide.

Vermason’s Statfree™ T2 mats include Ultraviolet (UV) stabiliser additives in the mat formula to stabilise colour retention, ensure ESD performance over time and eliminate surface layer deterioration resulting in cracking when the product is flexed. Additionally, we mark lot traceability information on the bottom of the roll every 0.9m to provide tracking information for lifespan of the product and to ensure quality control.

Top 3 Benefits of Statfree™ T2 Working Surface Matting:

  1. Superior wear, heat and chemical resistance.
  2. Withstands abrasion, stretching and tearing.
  3. Ultraviolet (UV) additives stabalise colour retention to ensure ESD performance over time and eliminate surface layer deterioration.
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