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Latex Gloves – Are You Allergic?


Many industrial manufacturing environments require workers to wear protective gloves, including during electronics and medical device production and assembly. Latex gloves not only protect workers from harmful chemicals but also protect products from worker contact and contamination during manufacturing Read more

ST 925 SMT Rework System–Three favorites combined into one nice savings


Save a few steps--and some money--with the Pace 925 SMT Rework System Pace has introduced a new low-cost “combination” system ideal for surface mount technology (SMT) rework. It’s worth adding up the savings by comparing the a la carte prices Read more

Metcal’s CV-5200 Connection Validation Soldering Station Changes Everything


You may or may not have heard about Metcal’s new soldering station, the CV-5200. The evolutionary tool removes much of the reliance on visual inspection of hand-soldered joints and adds a second, more technology-driven method for validating a successful Read more

PCB Rework – Evolving Cleaning Methods

Posted on by Andy in Printed circuit board rework, Technical Articles Leave a comment

Smaller devices makes PCB rework harder.

Today’s manufacturers of printed circuit boards (PCBs) strive for quality and drive operation yields close to 99% and above – yet some boards will still fail functional tests when coming off the assembly line and need rework. With the increase of smaller, better PCBs for smartphones and tablets, PCBs can cost upwards of $200 each. Original equipment manufacturers (OEMs) must develop effective and efficient rework processes and save the damaged boards when possible to minimize scrapping PCBs and operation losses.

The value of reworking faulty boards is quite clear. With the development of more sophisticated boards and the continuing demand for smaller and smaller devices, performing manual rework has become increasingly difficult.

Previously thought of as a very specialized process used by few OEMs, contactless cleaning is quickly becoming mainstream and mandatory for most PCB manufacturers to stay competitive and meet customer demand.

When performing PCB rework, technicians generally follow three steps –

  1. Remove the non-working component
  2. Clean the leftover solder from the ball grid assembly pads
  3. Replace the non-working component with one that works

Today, both the first and third steps have been automated and can be completed on rework machines. The second step, however, continues to remain in the hands of a skilled technician because of the intricate, critical nature of properly repairing a damaged PCB. Boards can be cleaned using different kinds of tools—from a wicking braid to a soldering iron—along with specialized tips for detailed work. The skill level of the technician can determine whether a board comes through the process undamaged and how often.

One common way a board can be damaged is during manual cleaning. If the soldering iron dissipates for a moment from the pad, it can cause the pad to stick to the wick. As a result, the pad can chip or lift totally off when the technician pulls the tool away. If the pad is destroyed, the PCB becomes scrap.

To help ward of this king of damage, manufacturers are creating thicker PCBs with multiple inner layers of copper.

Open vias and solder resist damage

Unfortunately, the newer PCBs can cause heat to dissipate faster when using a handheld cleaning tool —making sticking challenges even more of a problem.

Additional issues like molten solder flowing into electrical connections or into vias can also occur, causing shorts in the board. Also, if solder is removed inconsistently from the pads, the components may not adhere well and portions of the solder resist may be accidently removed by the wick. The solder can then flow into electrical connections and cause bridges and shorts when it’s put back into the rework machine.

One of the worst case scenarios, in addition to a PCB becoming scrap, is the creation of pad craters within the fiberglass substrate. These cannot be seen during inspection or by X-ray. Pad craters can happen when an operator presses too hard with their soldering iron or rests an excessively hot solder tip for too long on a board.

In this kind of damage, the pad and the solder balls remain connected to one another; however, the pad is not fully anchored to the circuit board, leaving it vulnerable to just the smallest jolt. If the product goes to market and this happens, the result may cause customer dissatisfaction.

Tough cleaning woes

Two different types of solder are used in manufacturing, with melting points of 183° C and 302° C (361° F and 575° F) respectively. Manual cleaning can change the melting temperature of solder on pads and become too low to form a connection, causing a dry joint. Also, package-on-package (PoP) chips cannot be manually cleaned with assurance or without the threat of the package bottom melting.

Advanced chip technology also causes PCB cleaning challenges. Even though one company’s breakthrough technology makes it almost impossible for criminals to access data, it also makes components difficult to clean due to differing pad sizes and uneven solder volumes.

Ceramic ball grid arrays present another huge challenge. These highly specialized boards, along with the components used in aerospace, military and other high-reliability applications, have become extremely hard to successfully, manually rework, and usually have to be trashed if faulty.

Alternatives – Contactless cleaning

Contactless cleaning or scavenging can significantly reduce the challenges associated with manual cleaning, and can be a substitute method in many applications. If no contact is made with the pad or board, possible mechanical damage is greatly reduced. Instead, precision-controlled tips clean pads too small and too close together for technicians, while software and equipment continually control thermal profiles.

All-in-one designs

Contactless cleaning has generally been used on very large, high-end machines or as an optional, retrofitted add-on that allows for the cleaning function to become part of the removal and replacement steps on a single rework machine. Stand-alone contactless cleaning machines require a much lower capital investment, plus other added benefits like great throughput.

The standalone machines take only a single operator to run and can increase the speed of an assembly line operation if used next to a standard rework machine. They offer excellent flexible opportunities for manufacturers to easily add contactless capability to their existing operations. If they presently have a standard rework machine and no scavenger add-on, a contactless cleaning machine can be added quickly to work side-by-side with their current system. This is a useful route if suddenly the OEM needs a quick way to add capability because of increased customer demand.

As chip sizes shrink, and production struggles to keep up with an ever-expanding demand for smaller and more powerful electronics, rework processes must continue to develop.

From a Metcal article –

From the original article – The Evolution of Cleaning Methods,in PCB Rework by Robert Roush and Paul Wood, Metcal


Ten Labels to Solve Your Engineering Challenges

Posted on by Andy in Identification, Labeling Leave a comment

Labels – Put the right one on

There’s a right label for every application and Brady has designed a handy cheat sheet to help you on your way. When choosing a label, you’ll want to ask yourself several questions –

  • Will the label be in a harsh environment?
  • Will your label face high, cold or fluctuating temperatures?
  • Will your label encounter chemical or abrasion?
  • Does the color of your label matter?
  • Does the label need to stick to a difficult substrate?
  • Do you want the label to be glossy or matte?

Brady offers an endless choice of labeling solutions. Whether barcode labels, electrostatic dissipative labels, equipment identification labels, rating plates labels, circuit board labels or identification labels, they will most likely have the perfect label for your application.

 Why’s it so important to make sure you have the right label for your application?

The wrong label could cause you to lose business, create a safety hazard, waste your time with replacing them or worse—lose the product all together because the label has been damaged or gone missing. Below you’ll see ten engineering application problems and their solutions.

Labeling Challenges and Solutions    
The Application Challenge Attributes Solution
1.       •         Wave solder environments for circuit boards and electrical component pre-process labeling Abrasion, high heat and low temperature resistant Polyimide material
•         Extreme wash protocol and cleaning chemicals
•         Auto apply equipment
2.       •         Component identification Abrasion, high heat, fuel/oil and low temperature resistant Polyester material
•         Bar code labels and rating plates
•         Use on glass, thermoset polyester plastic
•         and polyvinyl fluoride plastic surfaces
3.       •         Rating and serial plates Solvent/chemical, fuel/oil and low temperature resistant Metalized polyester
•         Durable and quality identification
•         Versatility in using characters, graphics and barcodes
4.       •         Requires excellent solvent resistance and print performance Abrasion, high heat and low temperature resistant Polypropylene material
5.       •         ID lab vials, centrifuge tubes, test tubes, straws Solvent, high heat, and low temperature resistant Polyester material
•         Frozen surfaces, including glass
•         Polypropylene stored in liquid nitrogen
6.       •         Nameplate identification, asset tracking, general purpose labeling Outdoor durability, high heat and low temperature resistant Weather resistant material
•         Surfaces constantly exposed to outdoors
7.       •         Durable labels, nameplates, schematics, control panels Outdoor durability; abrasion, solvent and high heat resistant Photosensitive anodized aluminum
•         Harsh operating environments
8.       •         Instant visual indication of heat exposure High heat and reversible temperature indicator Reversible temperature indicating
•         Components, industrial and household applications (electric pumps, rotating equipment, brakes, refrigerators)
•         In cold chains, hot spaces areas
•         Where temperature measuring difficult or impractical
9.       •         Permanent color, durable against abrasion, harsh fluids Outdoor durability, low temperature and high heat resistant Durable polyester
•         Use on regulatory, compliance, electrical components
•         Finished goods, automotive/passenger compartment
•         ID and asset tracking
10.  •         Use to ID external push-buttons, switches, internal connection points Abrasion, fuel/oil, high heat resistant, outdoor durability Polyester material
•         Requires name plate quality for rating, serial plates

Article based on an original publication by Brady.

 


Dry Air Static Control and Ionizers

Posted on by Andy in ESD News, Static Control Tips and Tricks Leave a comment

Dry air and ESD control

The specifications and devices being assembled determine the recommended humidity range for a manufacturing facility. When the air is dry, static control becomes much more challenging. Although ESD events may be reduced by increasing the humidity, unfortunately that same humidity may cause a reduction in the quality of moisture-sensitive devices because of corrosion, soldering defects and the popcorn effect.

Ionizer choices for reducing ESD

Although ionizers cannot replace grounding or shielding of ESD work surfaces, ionization can lessen ESD events in areas where dry air is normal.  Desco has number of ionization products available through All-Spec.

  1. Benchtop and overhead Ionizers – work surface ionizers create positively and negatively charged ions that are moved to the controlled area with fan-driven airflow.
  2. Point-of-use air ionizers – use compressed gas to combat electrostatic attraction neutralizing charges on particles causing contamination or visual defects on products.
  3. Laminar flow ionization bars – used with laminar flow hoods, controlled chambers and other contained applications.
  4. Room Ionization – reduces electrostatic discharge (ESD) and electrostatic attraction (ESA) in cleanroom environments.

For more information, consult the ESDA’s TR20.20-2008 RH information. Below find some of the significant statements about dry air and static electricity.

dry-air-popcorn-effectESD Handbook ESD TR20.20-2008 Section 2.3 Nature of Static Electricity:

  • Static electricity in the form of static cling and static shocks are more prevalent when the air is dry.
  • Heating interior air in the winter months dries out the already dry air in the higher latitudes.
  • Static charge accumulation is easier on dry materials since moisture on surfaces tends to allow charges to slowly dissipate or recombine.
  • Humidity control alone cannot provide static control since static charges are developed even at relative humidity levels of 90% and greater.
  • For most situations, 30 to 70% RH is considered the appropriate range.
  • Special areas, such as wafer fabrication, may require lower humidity control for processes that are affected by moisture (e.g., photoresist application).
  • Soldering is known to be affected by high relative humidity conditions (>70%).
  • Ionization is an important consideration in areas with low ambient humidity to aid in reducing charge accumulation levels and provide neutralization of charges after they are developed but before they can cause difficulties.

 

desco-point-of-use-air-ionizerESD Handbook ESD TR20.20-2008 Section 5.3.16 Humidity:

  • Humidity is beneficial in all ESD control program plans.
  • Contact and separation of dry materials generates greater electrostatic charges than moist materials because moisture provides conductivity that helps to dissipate charge.
  • ESD effects are most noticeable in the winter since heating systems reduce building environment moisture.
  • Geographic location (desert vs. coastland) is a major contributor to ambient conditions inside buildings.
  • Any circumstance that results in a low relative humidity will permit a greater accumulation of electrostatic charges.
  • Relative humidity above 30% in ESD protective areas is desirable as long as other adverse conditions are not created as a result of humidity levels.
  • In general, an upper limit of 70% is desirable to prevent corrosive effects on the metal portions of electronic devices and assemblies.
  • Dry air increases the tendency to generate electrostatic charges on dry materials and performance of many ESD protective materials degrade.
  • When exposed to low humidity conditions, some ESD protective materials become totally ineffective or become sources of electrostatic charges.
  • Evaluation of ESD control materials should include performance testing in controlled environments at the lowest expected operating relative humidity level.
  • Manufacturers of ESD protective materials should be able to provide performance data in regards to relative humidity.
  • Materials should be tested in moderate humidity conditions as well to ensure they do not become “too conductive” and present a potential safety hazard to personnel working with substantial voltages. See the Personnel Safety section of this handbook for further guidance in this area.

 

Humidity control alternatives

 Humidity control in factories or physically large areas or buildings can be difficult and expensive. In smaller rooms or areas, it may be possible to use portable humidifiers to raise the immediate area humidity. However, in many large facilities and factories the environmental systems need to include steam generation and monitoring equipment to control humidity. This type of equipment is expensive to install and purchase especially in pre-existing facilities. To reduce the total cost impact, companies should consider the need for humidification equipment when planning new facility construction.


Zero in on Smog with Weller’s Fume Extractors

Posted on by Andy in New Products, Product Reviews Leave a comment

Weller Zero Smog Fume Extractors Compared

 

Smog – fog or haze combined with smoke and other atmospheric pollutants

Weller’s fume extractors remove dangerous gases and harmful particles out of the air, typically while soldering to create a healthier environment. If you’re in the market for a fume extractor, one of your best bets–Weller’s Zero Smog line including the Zero Smog TL (their newest model), Zero Smog EL, or the Zero Smog 2, depending on your overall work conditions and needs.

Zero Smog TL

The Zero Smog TL, Weller’s newest fume extractor has several appealing benefits. Probably the most liked—the low noise level. The other may be the extra-large filter surface resulting in an increase in the life of the system. Filters can be a pain to change, so the system also allows for easy filter replacement.

Choose from two different unit kit models (Zero Smog® EL Fume Extraction Unit Kit, Zero Smog® TL Fume Extraction Unit Kit with Filters, Brackets, Arm, Hose and Switch, 120V) and one unit-only model (Zero Smog® TL Fume Extraction Unit with H13 and F7 Filters, 120V).

Summary –

  • Low noise levels
  • Automated filter change notification system
  • Easily operated and easy filter replacement
  • Exceptionally large filter surface
  • Longer service life due to exceptionally large filter surface

*For connection to a WX /WT station a WX/WT Hub is needed

Zero Smog EL

The portable Zero Smog EL touts a high level of extraction power of 2,500 PA—used mainly for light duty removal of particles. The long life, brushless turbine and blower capacity of 220 m3/h plus the two-person capacity make for a good, solid choice. The system has an easy filter change and long service life due to the maintenance-free brushless EC turbine.

Comes as a unit (Zero Smog® EL Fume Extraction Unit) or a kit (Zero Smog® EL Fume Extraction Unit Kit).

Summary –

  • Fume extraction unit for 1 to 2 workplaces
  • Fine dust pre-filter M5; change out without having to change main filter
  • Active carbon foam for effective gas filtering
  • Exceptionally large HEPA H13 filter surface 2,4m²; increases filter lifetime
  • 4-speed setting and power regulation
  • Filter monitoring and filter alarm ensure timely filter change

 

Zero Smog 2

The Weller Zero Smog 2 is one of their more economical systems built to manage hand soldering fumes as well as fumes caused during gluing, cleaning and filling work. This is a small workhorse system that can handle both general and heavy duty soldering and accommodate two workplaces.

Comes as a unit (Zero Smog® 2 Benchtop Fume Extraction Unit 120V) or as a kit (Zero Smog® 2 Benchtop Fume Extraction Kit with ALFA Funnel Nozzle, 120V).

Summary –

  • Economical unit purifies air for up to two workplaces
  • Easy filter exchange
  • Quick and simple installation
  • Portable fume extraction unit

 

See all Weller Zero Smog extractors

See all Weller fume extractors


Ten Things You Should Know About LEDs

Posted on by Andy in LEDs, Technical Articles Leave a comment

LEDs – Know the basics

From manufacturers to universities, LEDs are quickly replacing conventional light sources. Knowing a few basics may help you weave your way through this wave of the future. Here are lighting manufacturer Luxo’s suggestions for things you should know about LEDs.

  1. What is an LED (Light Emitting Diode)?

An electronic component that generates light in a semi-conductor material. Under the right circumstances a diode may provide different wavelengths of seeable light.

  1. LEDs are not new.

Some people may recognize LEDs as being the red or green signal markers on hi-fi’s and TV sets—usually low-powered LEDs. High-powered LED costs have dropped in the past couple of years and operate at powers of around 1 W making them attractive to most industries. Forecasts show that by 2020, almost 50 % of all new and replacement light source unit sales will be based on LEDs–and because LEDs cost more than conventional lighting, the value of the LED sales will be even higher.

  1. LEDs last longer and don’t need to be replaced as often as most conventional lighting.

LEDs don’t have any movable parts or filaments to break so they last longer. This makes them very convenient with installations and replacements of challenging luminaires especially those at excessive heights and other difficult to service locations, e.g., windmills, telecommunication towers and chimney stacks.

  1. LEDs are more efficient than many conventional light sources.

All of the light emitted by an LED points in one direction allowing for less reflections inside the luminaire making them very suitable in situations where only downward lighting is needed. However, if both upward and downward light distribution is needed, the LED is less suitable, e.g., if compared to a T5 fluorescent lamp.

  1. LEDs offer new possibilities for color tuning to evolve.

Because LEDs are electronic components, they can be easily controlled (tuned) using software and control gear. An LED luminaire color can be mixed and may include red, blue and green diodes resulting in either colored light or white light.

The different color temperatures make it possible to produce cool and warm colored light. This capability comes in handy in office environments, schools and hospitals where concentrated light might be warranted, e.g., during a patient examination. LEDs can also be tuned to a warm temperature where more relaxing lighting may be desired, e.g., yoga cool down.  This attribute is also being maximized to increase the growth of plants and reduce water consumption.

  1. Temperatures inside a diode define an LED’s lifetime.

Heat management is the key to controlling the life of an LED and the temperature inside the diode. The temperature within an LED may get very high causing it to slowly emit less and less light. The higher the internal temperature, the faster the lumen degradation. Higher temperature on the LED chip (known as the junction temperature) speeds up the decline.

Lumen – a unit of luminous flux in the International System of Units, that is equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. 

  1. Understanding LEDs and lifetime, and diminishing output.

The amount of light from the light source at a future point in time is called the lamp lumen maintenance factor, or LLMF.  The lifetime of an LED module is defined as the time it takes until its light output, or lumen maintenance, reaches 70% of the initial output (L70). This means the module doesn’t die instantly as do most conventional light sources; instead it slowly dims down. The luminaire industry has standardized LED lifetime L70 to a minimum of 50,000 hours.  This corresponds to an LLMF of 0.7 as long as the lifetime of the lighting installation is set to the same amount of hours.

  1. The color spectrum of an LED comes from its color rendering capability.

Sunlight, halogen and metal halides possess complete spectrums while sodium lamps,

fluorescent tubes and LEDs have varying power distribution curves. Cool white LEDs have more blue light in them; warm white LEDs have more yellow and red light. 

  1. The LED driver is the auto pilot of the LED luminaire. Proper drivers help LEDs to stay cool and stable.

LED drivers differ from conventional power supplies because an LED driver responds to the varying needs of the LED supplying constant amounts of power as its electrical properties change with temperature. Choices include constant current for serial connections or constant voltage for parallel connections.

LED driver advantages –

  • Short response time – switches and dims immediately and can dim all the way from 0.1 to 100%
  • Very efficient at producing colored light

 

  1. Watch the LED’s Total Cost of Ownership (TCO)

Many applications warrant using LEDs, but not all. Analyzing the TCO when investing in LEDs including the energy costs, lamp change costs and cleaning costs can be crucial. Take time to consider all costs and suitable applications before making a final decision to transition or make new investments in LEDs.

 

 

Infographic showing the history of the LED light