Download our slide show here: CM2800 Constant Monitor Capabilities 

ESD Constant monitors reduce production costs by eliminating the time spent on testing wrist straps before each shift. Further savings may be realized by reduced ESD damage from broken wrist straps. Transforming Technologies manufactures two types of monitors:

Impedance (or single wire) constant monitors

The impedance monitor uses a detection circuit designed to reduce false alarms and eliminate adjustments. It uses the phase difference between current and voltage to detect changes in impedance of the cord, band and person. A very low AC voltage is used for constant sensing. Any standard wristband and coil cord can be used.

Resistance (or Dual Wire) constant monitors

This type of monitor is used with a two wire (dual conductor) wrist strap. When a person is wearing a wrist strap, the monitor observes the resistance of the loop, consisting of a wire, a person, a wrist-band, and a second wire. If any part of the loop should open (become disconnected or have out of limit resistance), the circuit will go into the alarm state. An important feature of the Dual Wire Wrist Strap is that even if one conductor is severed, the operator has reliable path-to-ground with other

Transforming Technologies Line of Constant Monitors.
Click here for more information.

The Need For ESD Socks

The combination of ESD flooring and footwear can be an effective way to ground personnel to control electrostatic discharges when using a wrist strap is not practical. For this system to be effective, the ESD flooring and footwear must have a low enough resistance to allow the voltage from the operator to flow to ground. There also must be a good contact between the person and the ESD footwear.

While ESD shoes may be made with conductive materials, they require a layer of perspiration in the sock to provide a path-to-ground. This is a concern because there are many variables between people. Per ESD Handbook TR20.20 section 5.3.3.5 Common Testing Problems “Occasionally, footwear may indicate a high resistance… [A contributor being] heavy or insulative socks, or the absence of a sweat layer due to differences in temperature between the inner surfaces of the shoes and the wearer’s feet.”

You may see inconsistent resistance measurements from person to person, especially during colder months when employees wear heavier socks and sweat less. One person may fail a test at the start of a shift, and pass ten minutes later after a sweat layer is formed.

How much time is wasted waiting for shoes to pass a test?
Or worse, how many sensitive items does a person come into contact with before their ESD shoes are truly acting as a path-to-ground?

Eliminate these variables and ensure a consistent path-to-ground with conductive ESD socks from Transforming Technologies. ESD socks are made with conductive yarn which provides a reliable electrical path from the start and rely less on the wearer’s skin resistance for repeatable performance regardless of the environment.

How to Choose an ESD Floor Mat

Choosing An ESD Floor is an Important Step in Eliminating ESD Damage

An ESD Floor mat is a very important part of a Static Protected Area.  ESD mats are designed to eliminate static on its surface and of people standing upon it.   A conductive material embedded within the mat draws in all the static and sends it to ground (earth). This is usually accomplished by connecting the mat to ground (typically the center screw of an outlet) with a floor mat ground cord. It’s important to wear ESD footwear such as heel grounders or ESD shoes when using an ESD floor mat, otherwise the static will stay on the body.

A quick search online or in ESD catalogs reveal a myriad of ESD floor mat options. What are the main considerations in choosing an ESD mat?

1. Intended Use: Where are you putting the floor mat? Different styles work best in different locations.
2. Material: Are you trying to protect your floors from wear-and-tear? The floor mat material makes a difference.
3. ESD Properties: Not all ESD floor mats have the same ESD properties.

ESD Mats: Intended Use

ESD mats are generally found in three categories:  Anti-Fatigue, Floor Runners and Floor Tiles.  The type you choose depends on the intended use:  Will people be standing on them for long periods of time? Choose an ESD Anti-Fatigue Mat.   Do you need to cover the floor?  Will wheeled carts need to roll over them?  Choose a ESD Floor Runner.  Do you have a large are to cover? ESD Floor Tiles may be your answer.

ESD Mats: Anti-Fatigue Matting

ESD Anti-fatigue mats, research shows, make a more comfortable worker, which makes a more productive worker with fewer injuries and increased productivity! ESD Anti-fatigue comfort mats are essential where workers stand to help ease leg, foot, and lower back fatigue and pain. Anti-fatigue mats come in a variety of styles and thicknesses to meet your needs and budget.  Some are made from spongy foam material that is soft to the touch and others are made from rubber that may feel hard at first.  You need to stand on a mat for an extended period of time to truly evaluate it. You may have to try our several different types to find the style you prefer.

ESD Mats: Floor Runners

“Floor runner” is a term that is used to describe mats that are long and narrow and that cover large areas.   ESD Floor runners are typically found in building entrances, hallways, and in front of long workstations.  They are usually thin so as not to be a trip hazard and provide little, to no anti-fatigue comfort. Common ESD Floor runners may have a V-Groove or a smooth surface. Some runners are designed to be durable and ridged enough to to be used with rolling ESD chairs.

ESD Mats: Floor Tiles

In some applications, it is preferable to cover a large section of a floor or the entire room with ESD matting.  ESD tiles are used like puzzle pieces, interlocking together to build out large floors.  ESD tiles can come in laminate, vinyl or rubber tiles. Laminate tiles are usually thin and ridged and many types require you to glue them down. Rubber tiles can be larger and thick and provide anti-fatigue properties.  Some vinyl tiles are extremely durable, able to withstand forklifts.  A benefit of non-glued down ESD tiles is that they can be disassembled and reconfigured or moved to a new location.

ESD Mats: Composition:

ESD floor mats are usually made from vinyl or rubber.  Vinyl mats may be softer and less expensive, but are less durable than rubber mats. The most durable mats are made from rubber in which a single layer is molded into shape. Some floor mats use both: a durable rubber top layer and a spongy vinyl bottom.  These mats may sound like the best of both worlds, but tend to delaminate over time and fall apart.  Thickness, texture, and cushioning of the mat are also concerns depending on the application.  Regardless of composition, all mats should meet or exceed the requirements of ANSI ESD-S20.20 (see below).

ESD Mats: Electrical Performance:

All static control mats are not created equally. The terms insulative, conductive, and dissipative are all terms that subdivide ESD materials based on their individual surface resistance. Surface resistance is a measurement of how easily an electric charge can travel across a medium (Visit here to learn How To Test ESD Mats). For most applications, ESD floor mats should be in the conductive range.  Floor mats can become dirty over time which effects their ESD properties, so you want to start with a conductive mat to ensure you are grounded. Conductive materials have a surface resistance of less than 1 x 10^ 5 ohms/square. Dissipative items have a surface resistance of more than 1 x 10^ 5 ohms/square but less than 1 x10 ^11 ohms/square. An insulative material is one that has a surface resistance of greater than 1 x 10 ^12 ohms/square.

ESD Mats: Sizes:

ESD floor mats typically come in workstation sized mats such as 2’x3’ and 3’x5’, interlocking sections or in long rolls.  The material is easy to cut and has a long shelf life so if you have more than one area to cover or expansion is a possibility, purchase a full roll and cut pieces as needed.  Many suppliers also provide ready-to-use pre-cut mats with grounding hardware already installed.  These mats can be more expensive, but it can also be a great time saver.

Conclusion:

When choosing an ESD mat, first use your specific application to narrow your choices, such as mat material and electrical properties.  Carefully plan and budget your workstation so that you can choose to purchase a full roll or a pre-cut mat.  Finally, do not let cost dictate your decision – saving a few dollars on low-quality matting could have very costly consequences via catastrophic damage, latent failures and customer complaints.

For help choosing your ESD mat, please call Transforming Technologies at 419-841-9552 or email info@transforming-technologies.com

View Transforming Technologies ESD Floor Mats here:
http://mx.transforming-technologies.com/esd-floor-mats/

Microscopes are used for inspection and assembly of very small objects and are common instruments in electronic assembly operations.   It is critical that the microscope lenses remain clear and free of dust and other contamination and should be covered when not in use to protect the optics. Some manufactures of microscopes provide covers for the time when the scopes are not in use.  Typically the covers are made of vinyl.  While vinyl may provide good protection from dust and fumes, it is a significant static generator.

Common Vinyl Microscope Covers Generate a Significant Static Charge:

Static charge on vinyl covers is a problem in two ways: It may cause ESD damage to sensitive components and the static will attract dust which is a problem for the microscope. We measured a vinyl cover with a static field meter:

The vinyl cover in the photo above shows an electrostatic voltage of -5,500 volts.   Once the cover is removed from the scope the voltage jumps even higher to -12,000 volts.

ANSI/ESD S2020, the industry standard for ESD control programs, states that all nonessential insulators should be removed from the ESD protected area.

Since it is critical that microscopes be covered when not in use, it could be argued that the microscope cover is a process essential insulator.  ANSI/ESD S2020, Section 8.3.1 states that the ESD control program “shall include a plan for handling process required insulators in order to mitigate field induced CDM damage.”

The standard goes on to say that if the field is greater than 2000 volts/inch it must be kept more than 12” from the ESD sensitive item.   If the microscope is not in use, but work on ESD sensitive devices is being performed at the station, the vinyl scope cover becomes a significant risk.   The vinyl cover becomes even a greater risk if it is removed while there are ESD sensitive items at the workstation.

ESD Microscope Covers Are Static-Safe:

The best solution is to replace the vinyl cover with a microscope cover that is ESD safe, such as the Transforming Technologies MC1221W.   This scope cover is constructed of ESD safe material and does not generate a significant charge.

Even when the cover is removed, the charge remains very low and does not present an ESD threat to sensitive components in the area:

With Transforming Technologies’ MC1221W you can protect your microscope optics from contamination while keeping your work station ESD safe.

Email Transforming Technologies to protect your microscope with our Microscope Covers

Transforming Technologies has ESD versions of  other common items that can cause damage in electronics manufacturing:

• ESD Trash Cans
• ESD Pens
• ESD Rubber Bands
• ESD Sheet Protectors
• ESD Badge Holders

Transforming Technologies is proud to announce the addition of the StaticCare ESD Hand Lotion to our line of ESD Products.

How to install an ESD Workstation:

1. Lay the table mat flat on the workbench with the snaps toward the operator. (Tip: Mild heat (sun light) will remove creases caused by shipping.)
2. Connect the common point ground cord to the table mat by snapping it to the left or right snap.
3. Connect the coil cord to the common point ground cord by plugging the banana plug into one of the ground cord’s banana jacks.
4. Snap the wrist band to the coil cord. (Tip: make sure that the operator wears the wrist band on bare skin and tightens the band so that no gap exists between the skin and the band.
5. Lay the floor mat on the floor in front of the workbench with the snaps toward the bench.
6. Connect the floor mat ground cord to one snap on the floor mat.
7. Connect the common point ground cord and floor mat ground cord to ground. Use the green wire building ground point as specified in EOS/ESD Standard 6. Connection to this ground point is most easily accomplished by removing the center AC outlet plate cover screw, placing the screw through the eyelets from both ground cords, and replacing the screw. The wires can be moved to the left and right sides of the screw so that they do not obstruct the outlet.
8. Heel Grounders: Open the velcro strap. Place foot back into shoe and slip rubber cup onto the heel of the shoe. Insert tab into shoe and trim excess tab material with scissors if necessary.  Close velcro strap. Repeat procedure for other shoe.

Newly installed workstations should be tested for continuity. A surface resistivity meter with a “resistance to ground” function can be used to test continuity from the ground point to all parts of the workstation.

This week’s ESD Q&A question:

Question: Is there really a need for an ESD wastebasket?

Answer:

It is fair to wonder why there is a need for ESD wastebaskets. If the waste basket resides underneath a workstation and stays there permanently, it is extremely unlikely that a wastebasket could present a danger to ESD sensitive devices, regardless of the field voltage that may exist on the basket.

However, there are a number of circumstances  when the wastebasket could present a significant hazard to electronic products. The following are just a few examples of potentially risky scenarios:

Work surface cleaning:   The operator lifts the wastebasket to the edge of the work station to collect the debris being removed. Should product be present on the work surface and not contained in a shielding container, there is a good opportunity for exposure to electrostatic fields that exceed safe limits.

Lead trimming/board cleaning operations:   When trimming component leads or using aerosol cleaners on PCBs (Printed Circuit Boards), some operators will hold the PCB over the wastebasket to catch the clippings or solvent run-off. Many times the PCB will be placed well into the waste container to assure catching the unwanted materials. This operation puts PCBs and ESD sensitive devices very close to potentially significant electrostatic fields.

Aisle proximity:  Some wastebaskets have been observed in close proximity to production floor aisles where product transfer carts pass or may be parked. ANSI/ESD S2020 requires items that generate 2000 volts or more (measured at 1” from the item) be kept at least 12” from ESD sensitive devices. Using ESD wastebaskets eliminates the risk of carts being parked next to static generating baskets.

Taking out the trash:  The simple action of removing trash from the ESD sensitive area could generate a dangerous amount of static. Static is caused by movement, specifically friction. So moving the trash cans to empty them or removing the plastic trash bags from the can generates voltage and they could come in close proximity to sensitive components on the way out of the area.

While company ESD policies may prohibit some of the actions mentioned above, it does not mean that they will not occur from time to time. ESD wastebaskets provided assurance that the wastebasket will never be an ESD threat to your product.

What Do ESD Standards Say?

The ANSI/ESD S20.20 standard says to remove all insulators from the ESD protected Area (EPA). There is nothing specifically mentioned in the standard about Trash Cans or Waste Baskets. But most trash cans as well as trash bags are plastic, which is an insulators that can generate significant charges. It is better to be safe than sorry when is comes to static damage which is why we developed ESD-Safe Trash Cans and Waste Baskets.

Transforming Technologies offers three ESD wastebaskets in static dissipative polypropylene :

• WBAS28 – 7 Gallon ESD Waste Basket
• WBAS90 – 22 Gallon ESD Trash Can
• WBAS180 – 44 Gallon ESD Trash Can

We also supply a stainless steel ESD waste basket for clean room operations:

• WBAS28MET – 7 Gallon Conductive Cleanroom Waste Basket

If a liner is to be used for easier maintenance, Transforming Technologies offers them in both conductive and static dissipative.

WBAS 28

• Volume: 28 Quart (7 gallon)
• Height: 15″, Opening: 10.5″ X 14.75″
• Carbon Loaded

One of the requirements of any quality ESD control program is to minimize the charge (also called voltage) on operators. When operators are charged with static electricity, they can transfer this charge to the product and possibly cause damage or destruction. One effective way to reduce static charging on people is to ground them through the use of a wrist strap and coil cord. When working properly, the wrist strap system (band and coil cord connected to common point ground) can control voltages on people down to 10 volts and less and limit damage.

Wrist straps are the most common and effective way to eliminate static on personnel, but they are also the ESD control device that is most likely to fail over time. A broken wire in the coil cord, a dirty cuff interior, incorrect wearing of the strap (too loose or placed over clothing), and high skin resistance are just a few of many causes of wrist strap failure. If wrist straps fail, the static charge on an operator will increase and may cause ESD damage without the operator even noticing. Therefore, it is imperative that measures are taken to assure that the operator is properly grounded when wearing a wrist strap.

The PDT800 is a deluxe “Near-Fail” wrist strap and foot wear combination tester with a digital read out, “near-fail” LED indicator, human body noise filtration, and options to test wrist strap only, foot only, or both wrist and feet.

ESD Test Stations

One way to assure that the wrist strap system is working correctly is to use an ESD Test Station. The ESD Test Station assesses the resistance of the wrist strap system (including the operator) and provides a pass/fail indication. Some more advanced test stations will also provide the actual resistance measurement and can even log test data on a computer. But the frequency of testing differs from company to company. Some require testing just once at the beginning of the shift. Other companies may require re-testing several times a day. Regardless of how many times an operator tests, there is a risk that the wrist strap will fail at some point during a shift.  Constant Monitors can eliminate this risk.

Transforming Technologies offers several testing station options that range from wrist strap monitors (WST200), wrist strap and footwear test stations (GTS600K), wrist strap and individual foot test stations (GTS900K), test stations with “near-fail” technology and digital display (PDT800K). These testing stations function with a standard wrist strap and coil cord using a banana jack connector and standard heel grounders.

Constant Monitoring

An ESD wrist strap plugged into a Constant Monitor. The monitor will alarm if there is a problem.

If a wrist strap fails the test at the beginning of a shift, the question arises, “When did the failure take place and how much product was handled after the failure?” Constant monitors provide assurance that the wrist strap system is working and alarms immediately if there is any disconnect from the operator to ground. There are several benefits to constant monitor systems:

• They provide immediate notification of a problem and alert the operator to not handle the product until the problem is resolved
• They monitor the wrist strap at the work location, eliminating the possibility of a functional wrist strap but a defective ground attachment
• They eliminate the need for recording and storing test results
• Some units will also monitor the work surface to verify that it is still connected to ground

The downside of constant monitors is that each operator must have their own dedicate monitor, which can be a costly initial investment.  But the savings overtime of product damage during manufacturing and lower warrant claims can make up for the constant monitor costs.

Transforming Technologies offers several low cost constant monitor options that range from monitoring a single operator (CM400), an operator and a work surface (CM410), and two operators and a single work surface (CM420). These monitors function with a standard wrist strap and coil cord using a banana jack connector.

Summary

Wrist straps are the most common method for removing charge from operators handling ESD sensitive products, but they need to be tested often to ensure they are working properly. ESD Test Stations can verify wrist strap operation but there is still a risk of wrist strap failure in between tests. Constant monitors solve this problem and can provide assurance that the system is working as designed and the products are being handled safely at all times.

 Question: Why do I get static shocks when I touch the door knob?

Answer: Static charges build up on shoes when you walk.

Most modern shoes have highly insulating rubber or plastic soles. As you walk, static charges can build up on the soles of the shoes. This is especially true if the floor is also insulating. Some older nylon carpets are particularly good at generating static electricity.  The charge on the shoes soles induces static electrical charge on your body, and when you touch something conductive, such as metal, the static will discharge and cause a the shock. If you are indoors, the point can be proved by walking around for a while with no shoes on – you will probably not experience shock.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Understand the Decade Scale

How to read a Surface Resistance Meter.

The Decade Scale is shorthand for electrical measurements, displayed in powers of 10

SRM500K – Surface Resistance Meter

and described in “Ohms”. A Surface Resistivity Meter is used to take these electrical measurements on all types of surfaces and materials, and the results are displayed in the Decade Scale.  Most meters will display results using colored LEDs that brighten according to each decade.  These measurements are important in ESD control because this is how to classify a material as Conductive, Dissipative or Insulative.

Ohms are the units used to describe the  measurements of electrical resistance and has a symbol that looks like this “Ω”.  Depending on the value, measurements can be in “kilohms”, or “meg ohms”.  The decade scale can be written in several ways and mean the same:  10⁵ , 10^5, 100 kilohms, or 100megΩ etc. The table below shows all the values important as it pertains to ESD or Static Control:

Decade Scale

10^3      =1 kilohm
10^4      =10 kilohm
10^5      =100 kilohm
3×10^5  =300 kilohm
10^6      =1 meg ohm
3×10^6  =3 meg ohm
10^7      =10 meg ohm
3×10^7  =30 meg ohm
10^8      =100 meg ohm
3×10^8  =300 meg ohm
10^9      =3000 meg ohm
3×10^9  =1000 meg ohm
10^10    =10,000 meg ohm
10^11    =100,000 meg ohm
10^12    =1,000,000 meg ohm

To learn more about the Decade Scale and Surface Resistivity Meters visit Transforming Technologies or call 419-841-9552