Technical Articles

Getting Rid of Charges Part 2: Personal Grounding Equipment

by David K. on February 6, 2012

Last week we went over what grounding does and why you need it, so this week we will start to look into methods of grounding. We noted before that static can come from two objects rubbing together. One of the biggest factors in creating an ESD-safe workplace is stopping static from the object that often moves the most: the human body. By walking, sitting down, moving your arms, or any number of other activities your body can generate static, so it is important to use personal grounding equipment to discharge this energy safely.

Shoe Grounds

If you stand or walk around while working with static sensitive equipment then shoe grounds are essential. These devices wrap around your shoes and create a path to ground from your body through the ground strap to the ground. However, in order for these to work properly you must have conductive or dissipative flooring and you must wear a shoe ground on each shoe. When you are walking one foot is off the ground a lot, so you need a continuous path through each shoe. Shoe grounds come in many styles, including heel grounds, toe grounds, and full sole grounds.

Wrist Straps

When working at a desk shoe grounds are not as effective since your feet are not always touching a grounded surface and are often hanging from your chair or on a footrest. In this instance wrist straps are used to ground the operator, as they provide a constant ground path. Wrist straps can be plugged into an ESD-safe mat, as well as other ground points. Workstation monitors are one such ground, which have the added benefit of testing your equipment and notifying you if any part of your system fails. You can find workstation monitors that just test wrist straps or both wrist straps and ESD-safe mats at the same time.

That is all for this week, make sure to check in next Monday for more information on grounding your workstation!

Getting Rid of Charges Part 1

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(Exclusively from Jonard!) What are Force Gauges?

by Guest on February 1, 2012

(special thanks to Jonard for guest blogging the content below!)

Jonard Force Gauges (also referred to as Dynamometer or Tension Gauges) are all ergonomically designed industry standards for measuring force.

Jonard offers 3 different styles of force gauges: large and small force gauges, economy push- pull force gauges, and push-pull precision force gauges. These gauges are used by a multitude of industries including the electronics, telecommunications, business equipment, medical, automotive, chemical, plastics, machinery, manufacturing plus many others…with over 1000 different applications for measuring, calibrating, standardizing, testing and evaluating.

How do you use a GD Series Gauge? Measuring anything using a Jonard Force gauge is simple, fast and easy. Just place the point of the gauge arm perpendicular to the force to be measured. Reading can be taken in both directions – clockwise and counter-clockwise, and with the maximum reading pointer you have your measurement saved for easy reference. For example, these gauges are perfect for testing the nose wind vane and cable tension in most commercial aircraft. They are being used on nuclear submarines, plus many other more mundane applications.

So, who else really uses force gauges and what do they use them for? The Railroad Industry for one. Have you ever noticed the arms that come down to stop traffic while you are sitting at a railroad crossing? Our GPP series gauges are used to calibrate these arms. These same gauges are used for the arms that keep you from leaving a parking garage. We also sell our GPP push-pull precision forces gauges to slot machine companies; they use them to calibrate the tension on the wheels that spin inside the machines. Our gauges are also used in manufacturing and testing the tension on Robotic arms at Ford and GM plants and testing springs on toys manufactured by Playschool.

One of the best examples and my personal favorite for real life applications was a call we received from a gentleman at a nursing home. He called to tell us our GPP precision push-pull gauge made life around the nursing home much easier. He was having an issue with the weight of the doors and the force required to open them. Some of the elderly were having trouble opening the doors. He used a GPP-5 to test the strength of his residents and he adjusted the doors accordingly. He was very happy to share his story and he wanted to give us a personal “thank you.”

From high tech testing of robotic arms in manufacturing, to testing the force required to lift a traffic arm, to opening a door for grandma, to nuclear submarines and Boeing aircraft, Jonard Force Gauges cover a wide array of applications for everyday life.

All-Spec Industries is an authorized distributor of Jonard tools. Jonard is a leading manufacturer or professional and precision hand tools for use in a variety of industries including CATV, telecom, fiber optic and electronic.

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Getting Rid of Charges Part 1: Basics of Grounding

by David K. on January 31, 2012

Proper personal grounding techniques are probably the most important part of any ESD-safe workstation. However, you may not know what grounding actually does to get rid of a charge. Today I am going to go into some basics of gaining and losing charges, so if you already know how this works, make sure to visit next week when I go into some specific grounding techniques.

What does it mean to gain a static charge?

For an object to gain a charge, it must either lose or gain electrons. The movement of protons and neutrons, the other parts of atoms, tends to be restricted. However, electrons can move across objects and as they move, they create charges on objects. If an area has more electrons than protons then it has a negative charge; if there are more protons than electrons then it is positive.

Different objects can have the ability to allow more or less electrons to move through them. When it is hard for electrons to move through an object, it is called an insulator; when it is easy, it is called a conductor. Glass and plastic are examples of insulators, while most metals are conductors.

How do you gain a static charge?

One of the easiest and most common ways that an object gains a charge is by tribocharging, which is rubbing two different objects together. Because electrons do not move through insulators easily, they can build up a charge when electrons are transferred to them. If you rubbed two conductors together, then the objects would easily return to equilibrium of protons and electrons.

While rubbing two objects together creates a static charge, it is not the action of rubbing or the friction involved that transfers electrons. Electrons move naturally whenever two objects touch. Rubbing them together increases the area of contact, which allows for a larger number of electrons to be transferred.

How do you get rid of a static charge?

When you have a buildup or a lack of electrons on an object, then it has a charge. However, objects naturally want to reach equilibrium of protons and electrons. The fastest way to do this is to ground the object by touching it to a conductor. By touching a conductor, which allows electrons to move freely, the electrons are allowed to flow to whichever object needs more to reach equilibrium.

You cannot always reliably ground yourself just by touching a small conductor, which is where proper grounding techniques come in. In order to fully reach equilibrium, it is most effective to touch a conductor that is connected to the earth. Because the earth is large and the charged object is small, the charged item will fully discharge or gain electrons as needed to reach equilibrium.

Insulators cannot be grounded through this method, as electrons do not move across them easily. Instead of touching an insulator to a ground cable to remove a charge they must be neutralized through ionization. Bench top or overhead ionizers are very useful for this, but we will go into more detail on this method in an upcoming post.

Why does grounding matter?

Grounding is important in any ESD-safe work area to protect objects that are sensitive to static shock. If a person has a charge and touches a circuit board, then there may be a transfer of electrons, more commonly known as a static shock. This static can harm many electronic devices. However, if you are grounded then you will not have a charge, reducing the chances of discharging this destructive static.

Next week we will look at specific grounding techniques, so make sure to check back in on Monday!

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(Exclusively from Virtual Industries!) Manual Handling Of Delicate Parts

by Guest on January 27, 2012

(special thanks to Tom Mealey at Virtual Industries for guest blogging the content below!)

Handling parts during assembly can entail a variety of different tools. Larger parts can easily be handled by hand without the assistance of any special tooling. As parts become smaller and more fragile in nature specialized handling tools become more important. For many decades the handling tool of choice has been the mechanical tweezer. The tool is simple to use and many people have tweezers at home used for applications from removing splinters to plucking eyebrows. A disadvantage of mechanical gripping is that fragile parts may be damaged or dropped during the handling process.

Enter the age of high technology electronics and the need for manual tools that can handle parts ranging from 300 mm to as small as 100 microns. The ideal tool for handling parts without imparting contamination, damage or dropping is the vacuum-tweezer. The vacuum-tweezer typically consists of a pen or wand type device with a vacuum source and a pick-up-tip. There are a variety of vacuum pens available depending on the handling application. There are self-contained vacuum pens that are mechanically operated, tools that are battery powered, compressed air powered tools that have an internal venturi vacuum generator, tools that connect to in-house vacuum sources and systems with vacuum pumps that plug into standard electrical outlets. Each tool has advantages dependent upon the handling application. These tools are fabricated with materials that render them safe for Cleanroom and static dissipative for ESD sensitive applications.

Let’s start with the manually operated vacuum tweezers. These tools are ideal for handling parts that are a quarter inch in size up to several inches. There are two basic styles, each requiring rubber vacuum tips for proper operation. First, the pen style PEN-VAC has a button on the side, an internal bulb and an interchangeable rubber vacuum tip attached to the front of the tool. When the button is depressed air is forced out of the tool, the rubber tip is then placed on a flat surface of the part to be handled. Releasing the button draws the air back into the tool. A vacuum is created between the part and the vacuum cup and the part can now be handled. A second depression of the button releases the part. Operation is that simple.

Secondly, there is the BULB-VAC or HANDI-VAC style. The operation is very similar to the pen style. The bulb has a rubber vacuum tip attached to the front of the tool. When the bulb is squeezed, air is forced out of the bulb, the rubber tip is then placed on a flat surface of the part to be handled. The squeeze on the bulb is relaxed to draw the air back in and a vacuum is created between the part and the vacuum cup. The part can now be handled. A second squeeze of the bulb releases the part. The Bulb-Vac shown here is ideal for placing modern processor chips into sockets on computer boards.

In addition to the different styles of vacuum pens, there is a variety of specialized pick-up-tips for different applications. For example, when handling flat substrates such as wafers, solar cells or flat panels, the tips themselves are flat. These tips require a constant vacuum source to overcome leakage between the substrate being handled and the pick up tip itself. Substrates handled with this type of device typically range in size from two to twelve inches.

When handling parts smaller than an eighth of an inch, a small-part-tip is recommended. The business end of the small-part-tip typically has conical point ending in a flat area with a hole drilled down the center. The holes vary in size from 0.060” to 0.003”. The tip with the smallest hole size easily handles 100 micron size parts. This style of tip is used with any of the above mentioned systems that provide a constant vacuum source such as the bench top tools that plug into an electrical outlet. In this case, the vacuum pen has an air hose connected to the back of the tool and the pick-up-tip is on the front of the tool. To handle parts with this system, you simply touch the tip to the part and it is gripped for pick and place. To release the part, just tap the control button on the side of the pen. Applications for this style of tip include handling items such as SMD components, small ball lenses, miniature springs, small optical fibers, etc.

Battery powered tools are used where freedom of movement is a consideration. For example, in a Cleanroom operation a battery powered wafer wand has several advantages. First of all, there are no hoses to get in the way. Vacuum hoses in a Cleanroom can collect particles that may spread and interfere with deposition of circuitry. Vacuum hoses can be stepped on or tripped over. Additionally, a vacuum hose attached to a wafer wand restricts dexterity during the handling operation which may result in dropped, chipped or scratched wafers. A portable battery powered wafer wand such as the PORTA-WAND eliminates all of these issues. The handle of this tool contains a miniature vacuum pump, a battery as the power source and a press fit connector on the front of the tool that will accept a variety of different handling tips. The button on the front of the tool is depressed to engage the vacuum. The tip is placed flat against the substrate to be handled and it is firmly gripped for handling. Releasing the button turns the tool off and the substrate is released.

All of the applications for vacuum handling are too numerous to cover in this article. Most applications can be solved using off the shelf pick-up-tips. Some applications require custom tips. Vacuum tweezers provide industry with solutions for manual handling of delicate parts with out damage, dropping or contamination.

For more information visit Virtual Industries, Inc. at www.virtual-ii.com

Tom Mealey

Executive Vice President

Virtual Industries, Inc.

All-Spec Industries is an authorized distributor of Virtual Industries vacuum pick-up tools. Founded in 1987, Virtual Industries has been a leading supplier of manual vacuum handling solutions for over twenty years.

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What is REACH Legislation?

by David K. on January 16, 2012

REACH is a piece of legislation that is currently in force in the European Union. Along with RoHS and WEEE, it is one of the three main regulations that affect how electronic products are made and distributed throughout the EU. While they are not in effect around the world, anyone who wants to market their products to the EU has to deal with them, and the trend seems to be that many countries are following suit with these regulations.

While RoHS limits what electrical products can be made from, and WEEE regulates the recycling of old electronics, REACH sits in the middle by making sure consumers have access to the types and properties of chemicals in products. The goal of REACH is to have manufacturers know what chemicals are in their products and recognize any risks those chemicals may pose.

Manufacturers and importers to the EU must compile all of the information on the chemical properties of their products and register it with the European Chemicals Agency (ECHA). Along with the chemical properties, they must also have information on how to safely handle and use the products. Also, manufacturers are called upon to replace dangerous chemicals with less hazardous ones if a suitable alternative exists.

The REACH legislation also includes provisions for companies to work together to make products safer. Companies who use similar chemicals are encouraged to share information to make sure that all substances are registered properly. This is meant to lead to increased accuracy in information on chemicals, and should help smaller companies that have a harder time testing each substance in their product. By working together, companies can find potential hazards that they may have missed themselves.

Want more information on REACH legislation? The European Commission on Environment and the ECHA both have great information for the EU, and the United States Export website has some information for US companies. Make sure to check in next week for the last part in our series on environmental legislation where we will be looking at the US legislation on conflict minerals.

Read Part 1 on RoHS here.

Read Part 2 on WEEE here.

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