Ask the Toolman - Users Review & Guide

  • ESD and Static Control Guide

    ESD_StaticWhen working with a printed circuit board, it is important to be aware of electrostatic discharge (ESD). ESD is a common problem that occurs more often than most people realize. When it becomes a serious issue, it can cause major damage to any project. The amount of damage that ESD causes can be catastrophic and force you to replace expensive equipment or scrap the job completely. It is crucial to understand, monitor, and control ESD especially when dealing with electrical devices such as circuit boards and sensors.

     

     

    What is ESD?

    ESD occurs when there is a sudden change of electrical pulses between carriers of static electricity. These exchanges can occur between objects, people, and electrical devices. Some common ways people become statically charged is by walking across a carpeted area, sitting in a chair made of urethane foam, or picking up a poly bag from a bench.


     

    Types of ESD Symbols

    1) ESD Safe – Hand, triangle, and circle.

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    2) ESD Sensitive – Hand and triangle

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    What Causes an Increase in ESD?

    Whenever there is an assembly of several people working in a particular area around sensitive electronics, there is a possibility for high voltages accumulating on workers’ bodies. In addition, conditions where there is low humidity can cause an increase in ESD. The type of floor used can also contribute to a high exchange of electrostatic discharge.


     

    Ways to Prevent ESD

    It is important to create a work area that is free from ESD. One of the first things you should consider when setting up any workstation is to ensure that it is not set up in a carpeted area. Since carpet is a conductor for generating electrical flow, it is important to only use concrete or tile floors to get the best protection.

    Choosing the right equipment is also essential for ESD prevention. There are a variety of products on the market you can choose from including protective wrist straps and other gear to ensure a static free workplace.


     

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    Ways to Monitor ESD in an electronic assembly process

    Once you have a system in place that eliminates potential for ESD, then monitoring your work environment is also important. ESD monitoring can be done through outsourcing or on-site testing using an in-house static testing device such as the Desco 19325 Full Time Continous Single Station Monitor. This type of equipment comes with advanced, innovative features that provide full-time ESD monitoring to prevent accidental occurrences and maintain a safer work environment.  In addition you can monitor ESD events with the 3M CTM082 ESD Pro Event Detector.  The CTM082 detects and counts the discharges as well as shows the relative strength of each ESD event.

    To prevent catastrophic loss and create a safer work environment, it is important to understand, monitor, and control ESD. Ensuring that all employees take part in helping to control ESD is also essential for a prevention plan. By using the right tools and providing education, ESD can be controlled safely.

  • 10 Common Hand Soldering Mistakes

    ThinkingIdeas-150x150Proper hand soldering is an art which you can excel at only after much practice. By knowing what mistakes to avoid, though, you may make the learning/practice phases of soldering much easier. Some very common mistakes, for example, include using improper tip sizes, using a higher temperature than recommended in order to finish sooner, and not using proper ESD precautions.

    Other glaring mistakes can include:

    1. Insufficient wetting (of pad): This usually involves not properly bonding with the pad after soldering, possibly prompted by dirty circuit boards. This can be avoided by applying heat evenly both to the pad and to the pin.
    2. Insufficient wetting (of pin): This happens when not enough (if any) heat is applied to the pin, thus not allowing the solder to flow properly, creating an uneven wetting of the pad but not the pin.
    3. Inadequate wetting for surface-mounted components: The mistake involves not providing enough solder to flow unto the pad, but only unto the pin. Both the pad and pin need to be heated evenly to avoid this; the pad needs to be heated first.
    4. Disturbed joints (not same as “cold joints”): This may come about if the work is not put in a vise (when necessary)—i.e., failing to stabilize the board or immobilize the joint(s).
    5. Cold joints: This happens when the solder does not melt completely, creating a lumpy/rough surface and the use of too much solder. This can be repaired with a hot iron—i.e., by removing excess solder.
    6. Overheating of the joints: This comes about by applying the hot iron before the solder is ready to flow properly, leading to burned flux (usually causing nasty messes).
    7. Solder-starved joints: This usually involves not applying enough solder to joints, thus forming weak joints that may in time give in to stress cracks and, ultimately, malfunction.
    8. Excessive soldering: This usually leads to rounded globs over the tip and pad, often leading to lack of proper connection/adhesion. These mistakes don’t have the concave look of a properly soldered joint.
    9. Untrimmed leads: Leaving excessively long “tails” may bring about short circuits if the leads ever touch nearby traces. These leads should be trimmed at the solder joint tops.
    10. Solder bridges: This mistake involves putting so much excessive solder as to allow 2 joints to melt together (creating a “bridge). Obviously, these connections need to be fixed.

    Conclusion

    Hand soldering isn’t easy but you can identify mistakes that you can easily avoid simply by knowing what they are and what precautions you need to take.ThinkingEngineer

  • 15 Surprising ESD Static Electricity Facts

    esd_symbol_lAlthough many people have heard or know about electrostatic discharge (ESD), there are still many facts about it that may surprise them. The reasons for this can include the many ESD myths/misconceptions still hanging around; another is the fact that ESD is a much more common effect than most people realize.

     

    Some of those rather interesting (if not bizarre) facts about ESD include:

     

    1. High humidity environments increase the chances for ESD trouble/activity.

     

    1. Engaging in simple everyday acts can be considered “risky behavior” in the world of ESD susceptibility. Some of those acts (and the charges they can produce) include:

     

    1. Walking across a carpet (1,500V to 35,000V)
    2. Walking across a vinyl floor (250V to 12,000V)
    3. Utilizing vinyl envelopes (600V to 7,000V)
    4. Working on a polyurethane chair (1500V to 18,000V)

    1. All electronic components/parts have different relative sensitivities to ESD—why they cannot all be treated the same. Some electronic components (and their electronic susceptibilities) to watch out for include:

     

    1. CMOS (250 to 3000)
    2. SAW (150 to 500)
    3. VMOS (30 to 1800)
    4. EPROM (100 plus)
    5. Schottky Diodes (300 to 2500)
    1. Parts degraded/damaged by ESD may pass operational tests only to malfunction in the field when subjected to stresses. In other words, ESD damage is often difficult to diagnose/pinpoint.
    2. ESD protection devices should not be optional. ESD will cause damage most of the time unless managed properly.
    3. ESD is not a modern phenomenon; people have known about it for hundreds of years. For example, people in the 1800s took measures to make sure that black powder was safe from ESD.
    4. There are still many myths surrounding ESD. Touching metal objects to discharge oneself, for example, does not make one ready/safe to work on ESD-sensitive material. Body charges tend to rebuild right away.
    5. Inserting components into printed wiring boards (PWBs) do not make them ESD-proof.
    6. Different, especially-tailored ESD management strategies are necessary for different settings/needs.
    7. ESD problems can come from seemingly unlikely sources (e.g., charged plastic faceplates).
    8. ESD precautions are not taken by all manufacturers at all times. Because of costs involved, some manufacturers cut corners and, thus, see their products fail in the field.
    9. Everything is not presently known about ESD. Every once in a while something new is learned about ESD.
    10. ESD solutions don’t always come in neat, clearly-predictable “packages.” Periodically, creative solutions have to be found for previously un-encountered dilemmas.
    11. ESD management doesn’t always require expensive equipment and techniques. Sometimes what is required is avoiding simple errors of operation.
    12. Contact does not have to take place for ESD to be a problem. Sometimes just getting near an electric field can impart ESD effects.

     

    Conclusion

    ESD is arguably one of the most interesting aspects of electronics. Both experts and amateurs continue to be amused by what can be learned about ESD.ThinkingEngineer

  • Take Care of Your Solder Tips when Lead-Free Soldering

    Lead FreeIn the mid-2000s, many electronics manufacturers were in a panic. The European Union had mandated that most electronic products be manufactured with lead-free solder by July 1, 2006, in large part because of concern about the effect of lead in discarded printed circuit boards (PCB) on the environment. This meant that anyone who wanted to do business in the EU had to "get the lead out."

    But what can be used instead of standard tin-lead solder, which was cheap and worked well? And what are the considerations to equipment lead-free solder presents?

    One of the most widely used lead-free solders has become SAC305 tin-silver-copper (Sn-Ag-Cu), in large part because of its reduced melting point. In general, however, lead-free solders are not as reliable for mission-critical applications such as military and aerospace. And one problem that's been reported with largely tin-based solders is the formation of tin "whiskers," which can cause shorts in electronics equipment.

    The generally higher melting temperatures of lead-free solders can cause soldering tip defects and premature wear when hand soldering. This, in turn, can lead to surface contamination and nonwettability. Using Sn-Ag-Cu solder, for example, can erode the iron plating on a solder tip four to five times faster than when using traditional tin-lead solder.

    To ensure longer life of your soldering tip when hand soldering, proper care of the tip is required. Tip temperature plays a big role in durability. Using a lower temperature, when possible, can mean increased solder tip longevity. Temperature modulation tools (Auto Turn Off) within the soldering station can help you keep the heat off as much as possible.

    It's also important to clean your solder tip regularly, especially when using rosin-based flux, which is highly corrosive. Cleaning should be done with a wet sponge or brass wire sponge to remove as much flux and oxides as possible after soldering.  If conventional cleaning methods do not work, consider using a tip polisher like the Hakko FT700.  ThinkingEngineer

  • Using Compressed Air Dusters to clean Electronic Circuit Boards

    As anyone who has ever looked inside electronics devices knows, they collect dust and fuzz like nobody's business. Technicians can tell you that first, electronics in use in virtually any environment from the home to the office are constantly exposed to dust (and, in the home environment, pet hair) and that secondly, the electrostatic charge that any electronics device generates attracts dust like a magnet does iron filings. It doesn't matter if the electronics device is a TV, home entertainment system component or computer, if its been in use any length of time, it'll have dust inside.

    The first thing a tech will do is use a product like Chemtronics ES1017 Dusteres1017es1217 to blow out the dust. Believe it or not, clearing the dust out of a system may actually repair a problem as some dust particles can be electrical conductors, making bad circuit connections and causing issues. Also, clearing the dust and debris out of a system with compressed air enables the technician to work in a clean environment which, in the case of computers that haven't seen a lot of maintenance can be very dirty indeed.

    In those cases, using a product like Chemtronics ES1024 Typhoon Blast Duster or Chemtronics ES1020 Ultrajet Duster with a heavier compressed air spray can make a huge difference. Dust not only can cake over chips and other components but can work its way under components and boards as well. With the higher pressure, that dust can be blown out where using a normal compressed air spray will require several tries to do it or won't do the job at all. Some dust "infestations" can actually leave a layer of fuzz on a circuit board that can literally be peeled away in a sheet before any duster can be used and in severe cases like these, having a high pressure duster is imperative.

    In normal situations, especially when a technician is doing maintenance runs, having an inexpensive duster like Chemtronics ES1217 Economy Duster is the best tool he'll have in his kit. Doing maintenance runs in an office environment is one of those necessary evils that may be boring to do, but saves time and money since keeping computers well-maintained is much easier than trying to repair them later and having a good supply of compressed air makes life a lot easier for a technician as well.

    When working on electronics, dust and debris is an unavoidable issue that any technician can tell you is simply part of the job. With compressed air to blow the dust and junk out of the device, not only can the technician get to work on the problem, using compressed air to maintain a system can actually keep problems from happening in the first place.

  • ASG How does a torque driver work and why do I need this for PCB Assembly

    asg_torque_driversASG torque driver 64110 CL-4000 is designed to create connections that are gauged to the correct tightness. Delicate equipment can be destroyed if too much or too little screw tightness is involved. The AG 64110 CL -4000 torque screw driver and other industrial equipment are designed to carry a certain level of force. If it is pushed beyond this limit it might break. The ASG 64107 CL-2000 makes building anything in a factory or work shop easier and more efficient.

    ASG Torque Driver_64116_2The PCB tool provides an on off push system for the driver and it automatically performs offering a faster assembly and a more efficient twist. These tools can operate with internal or external power sources. Without correct calculations it is easy for a product to leave a facility damaged. With a precision ASG 64107 CL-2000 equipment is safely put together and it is easier on the employee with good tools.

    For over 35 years ASG has been making quality assembly tools. Some people ask the question, why ASG how does a torque driver work and why do I need this for PCB Assembly? On an assembly line there is no time for continuously checking the settings on a screwdriver or wondering if the tightness is just right. Your money is on the line and so is the safety of your customers. The ASG torque driver 64110 CL-4000 assures the tightness and lets the product assembly move quickly along the assembly line.

    Providing the best products possible for people in the manufacturing industry, customers with home projects also enjoy the efficiency of the ASG torque driver. No matter what the assembly project using the best tools makes the difference.

    • Calculated callibration
    • Three torque ranges
    • Prevents over-torquing

    Utilizing the right tool for the right task is absolutely essential for any important project. The ASG 64110 CL-4000 torque screwdriver provides an efficient and effective tool for a wide range of assembly projects, especially for those that require absolute precision. The ASG torque driver is exactly what hobbyists and professionals need for their assembly needs.

  • 10 Myths of Electro Static Discharge ( ESD ) in Electronic Manufacturing

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    Although most people may have heard about electrostatic discharge (ESD), they may nevertheless entertain perceptions that are not accurate. In fact, even people who work in manufacturing sometimes succumb to misinformation (or a lack of knowledge) about ESD.

     

    Because electrostatic discharge is such an important and prevalent phenomenon, everyone needs to know about these myths.

     

    What Are Ten Such Myths?

    1) Electrostatic discharge is a relatively-modern problem.

    Actually, going back into the 1400s, care had to be taken to protect against black-powder mishaps at munitions facilities. Forts in the Caribbean and in Europe, therefore, instituted early forms of ESD control.

     

    2) ESD is only an issue with PCB, explosives and sawdust facilities.

    In reality, most manufacturing facilities have to keep an eye on ESD, especially in regards to electronic products/equipment.

     

    3) ESD problems are a rare phenomenon.

    Many times items are damaged or disrupted by ESD and, because no outward signs are present, people remain unaware of the damage. These disruptions are very common.

     

    4) Discharging fingers/tools before using them obviates any potential ESD mishaps.

    Unless the user are perfectly still, the human body (and tools) can rebuild a charge. This is not a suitable (per se) control option.

     

    5) Once products are mounted on circuit boards, ESD mishaps cannot occur.

    Just because components are mounted on circuit boards does not remove ESD dangers. In fact, charges may be more easily channeled to sensitive parts once circuit boards are involved.

     

    6) Only circuit boards with complementary metal oxide semi-conductor (CMOS) are subject to ESD issues.

    While most circuit boards contain CMOS-components, all circuit boards are susceptible (in one way or another) to ESD damage

     

    7) One has to touch an item to transmit an ESD to it.

    Actually, all that is needed is bringing the item near an electrostatic field to create potential ESD problems.

     

    8) An item that passes a peremptory test after a potential ESD incident is probably okay.

    Actually, damage as a result of ESD can manifest itself later or in ways that may be difficult to detect with any measuring device.

     

    9) A printed wiring board (PWB) permanently protects a circuit board.

    Actually, while the withstand-voltage may be increased with a PWB, it is no guarantee that ESD will not be a problem.

     

    10) Grounded metal can provide a safe haven from ESD.

    Static discharge can still reach or build on items mounted on or sitting on grounded metal.

     

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    Conclusion:

    Yet another myth is that there isn’t much you can do against ESD. Actually, a number of effective products can be used to protect against ESD, including anti-ESD wrist straps, mats, chairs, casters, sealed barrier bags, non-conducting materials, etc.

    While it may be impossible to completely protect against ESD, precautions can be taken which greatly reduce chances for mishaps. By knowing what to do and not succumbing to popular myths, you can help reduce the chances for ESD damage to sensitive, expensive equipment and components.

  • Soldering: Tips, Tricks, Techniques & Tools To Make Life Easier - Part 3: Tricks

    03-03-2012-02

    When dealing with electronics for either a living or as a hobby, using a soldering iron is almost second nature. It seems like every time you turn around, you're reaching for an iron to replace a resistor or capacitor, to fix a battery lead or to install a chip. Whether you're a professional technician or the weekend hobbyist, knowing some tips and tricks to make life easier is always appreciated.

    Here are some tips and tricks that work great for either the pro or the novice:

    - Make sure your solder gauge ( diameter ) matches the connections you're trying to make. Trying to deal with a large gauge solder when soldering in a chip is a recipe for disaster. Gauges are available from 0.015 , .020" , .025" , .031" (most popular) and all the way through 0.062" which means even large gauge plugs and gang-holes can be handled properly. Kester Tin/lead Rosin Core or Lead Free is available in most gauges.

    - Keep your tip clean! This can't be stressed enough and even though it was mentioned in the last article, a clean tip keeps you in control of your bead. (And no, wiping the tip on your jeans doesn't count!). I personally recommend the brass wire sponge because it provides better tip cleaning promotes longer tip life that can be caused from thermal expansion and contraction when using a wet sponge. Having said that, the wet sponge technique has been used for years and works perfectly fine.

    - Some people will suggest using a metal file to reshape the soldering tip or remove heavy oxides from the tip. I HIGHLY recommend that you DO NOT do this. A file will quickly where down the protective metal plating and once you get to the base metal, the tip is DEAD. If heavy oxides are an issue, clean you tip more often and use a tip refurbisher for extreme cases. Also, having extra tips on hand can be a lifesaver.

    - Here's another tip that can't get stressed enough. Clean boards make clean connections so before sitting down to work on a project or a repair, use something like TechSpray cleaners and degreasers to ensure your board is ready for you to work on it.

    - When soldering, one way to make sure you get a solid connection is to; the solder across the connection by putting the tip of your soldering iron on one side of the lead and, once it's been there for a few seconds to heat it, put the tip of the solder wire on the other side. You should see the solder flow into the hole and dimple as the hole fills. Once the solder flows into the hole, draw your iron and solder up and away to create a clean finish. If you're having and issue transferring enough heat to the connection, a small amount of solder can help in transferring the needed heat. I've seen where a ground plain is really soaking up the needed heat to make the connection. When this occurs, I'll add just a little solder to make a connection between the tip and the pad. This will assist in transfering the heat. If you have a very large ground plan, I would consider a small bottom side preheater like the Hakko FR830 or one of these other options.

    - Don't work in an air flow such as in front of a fan or an air conditioner. These will chill an iron faster than you could possibly believe and even if you're using the fan for fume extraction, the air flow can cause cold solder joints and can lead to real messes on a project or a job. If you need fume extraction, which I would agree in using, look at either an economical option or a high efficiency Hakko FA430-16 ( Hakko FA430 ).

    Keep in mind that your soldering iron, whether you own a full-blown Hakko FM206 soldering station or a basic Weller GT7A soldering iron, is your key to solid connections and great projects. Taking care of it will be your first priority.

    ThinkingEngineer

  • Lead free solders versus traditional solders

    Traditional solders made from a mixture of tin and lead were once a common staple in working with electronics. Lead free solders have arisen in recent years as alternative to the lead and tin compound.

    A gradual shift to lead free solders has meant a change in design and manufacturing of some electronic components. New designs compensate for the differences in soldering and help lead free solders last longer.

    One appeal of lead based solders is their low melting temperature. A lead and tin alloy has a melting point of 183 degrees Celsius. Lead free alloys are typically a mix of tin and copper or silver. Many of these alloys must reach 220 degrees Celsius or higher to hit their melting point.

    Soldering is important because it is used in designing and constructing internal electronic circuit boards in radios, TVs, computers and other electronic equipment. It is required to be durable so that electronic equipment lasts longer.

    This is an area where lead free solders offer a major advantage over traditional ones. A traditional solder has a tensile strength of 6,140 psi (pounds per square inch). Lead free solders, on the other hand, can boast a tensile strength of more than 9,000 psi.

    The biggest advantage for a lead free solder is that it presents less of a health risk. Lead can be toxic if enough of it builds up inside the human body. It can enter a person's body through skin contact or inhalation. That's one reason why lead was removed from gasoline and paint years ago.

    Lead exposure poses the greatest risk to young children because their immune systems are not as equipped to deal with it. Anyone who works regularly with solders should be aware of the health risks lead can pose.

  • Soldering: Tips, Tricks, Techniques & Tools To Make Life Easier - Part 2: Techniques

    03-03-2012-09

    Working in the electronics industry means you'll have to solder something at one point in time or another. If you work on car stereos, televisions, home electronics such as DVD players, computers, or even do cell phone repair, the odds are you'll have to learn to solder. Whether you're rebuilding an old radio for a hobby, repair the battery leads on a handheld radio or replace the power supply in a television, knowing how to solder, even knowing just a few basic techniques means you'll be able to take care of the job.

    Here are some techniques you'll appreciate knowing whether you're a novice with an iron or an old hand:

    - Use a HOT iron. Having a soldering station such as an Weller Digital Soldering Station or a Hakko Dual Port Station lets you know when you're iron is at the right temperature. Trying to use an iron that's too cool is the perfect way to make a real mess.

    - When working with virtually anything, tin your leads. This especially applies to stranded wire since strands can come loose and make a bad connection to another part. Tinning leads on capacitors, resistors, transistors and even chips means they'll make a fast connection when placed.

    - Clip your leads to the right length before soldering. Most leads on caps and resistors are much longer than necessary and clipping them to the right length before soldering makes a much neater, more stable connection. Also, a long lead can reach something metal like a case and create a shorted connection.

    - Use enough solder (but not too much!) If you've not used enough solder, a component may look like it has a good connection but it's actually a cold connection that can cost you hours of troubleshooting time. Too much solder can create jumped connections between components, can actually create a cold solder because it cools before it flows and (simply for aesthetics) looks unprofessional.

    - Keep your soldering iron tip clean. After virtually every connection you solder, wipe the tip on a wet sponge pad or brass wire sponge to remove flux and excess solder.

    - Use a board cleaner such as Tech-Spray degreasers and flux removers before and after a soldering job. Having a clean board makes for better connections and after you're through, cleaning off the excess flux makes for a neater appearance and could prevent shorted connections.

    - If you're working with a board with any low voltage chips on it, you'll want to make sure you're using either an ESD mat or pad or have a grounded wrist strap in place. Not only is it frustrating enough to solder in several chips but they're almost impossible to find if one gets damaged from electro-static discharge.

    One way to get better at soldering is to practice. That may sound like one of those trite sayings, but it is definitely true. Take time on an old board to remove and replace components so you can get the feel of how things should go. If you haven't soldered in a while, also sit down with an old board and practice a bit to get your technique back.

    ThinkingEngineer

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