It All Adds Up at Count on Tools

When you work from a home office, nothing is more enticing than an opportunity to “get out” and see a customer and take a facility tour. So, last week, “get out” I did and hit the road from Fayetteville, GA, up to participate in a tour of Count on Tools in Gainesville, GA.  (For those unfamiliar with Georgia geography and traffic – yes, that is a bit of a drive, but, thankfully, I-85 has been repaired.)

This tour was organized by the Georgia Manufacturing Alliance. This group serves manufacturing businesses in the state and provides monthly plant tours, educational sessions and networking opportunities  “designed to help make profitable business connections for our members.” They put on all sorts of very cool tours throughout the state – including one I was sorry I missed of the KIA plant. Jason Moss, the founder and CEO of GMA, has, in fact, been a great supporter of our local SMTA Atlanta Chapter as well as a featured keynote.

But, I digress. Back to Count on Tools – longtime CIRCUITS ASSEMBLY friend, supporter and 2017 Service Excellence Award winner for Automation and Handling Equipment. I was greeted warmly at the door by Curt Couch, president and CEO, and we chatted about how nice it was to see each other outside the confines of a busy trade show.  He and his wife, Rene, started this business about 26 years ago literally in their backyard. And what an amazing success story from such an unassuming but obviously visionary guy. He said he never expected this level of growth, but here they are today with about 40 employees and a 20,000-sq. ft. facility.

For those who may not know, COT is a precision component manufacturer specializing in CNC Swiss automatic machining using standard to exotic materials including stainless steel, titanium, Inconel and PEEK. They are a global supplier of precision engineering components to a wide range of industries. And, of course, in our industry we know them for their nozzles and tooling, automation tooling and component handling equipment. Just this month, they finished an expansion of their manufacturing facility.

The consistent comment from the tour group (which was comprised of professionals from other manufacturing and service facilities throughout Georgia) – “what a beautiful, clean facility, well run and organized.”  And, the camaraderie among the Count on Tools employees was evident as well.

Zach Shook, operations director, Marketing and IT was also on hand, and we discussed our upcoming travel plans for SMTAI and Productronica. I caught up with my friend Tom Foley from ASM, who is a customer of COT. Prime, a contract manufacturer here in Georgia, was also represented as well. (Shameless plug  – our next SMTA chapter meeting will be held at Prime, and our speaker with be Jeff Timms, managing director of ASM Americas.  He will speak on “Enabling the Digital World” which highlights many of the upcoming and future technologies which will drive the electronics assembly industry into the future.)

All In all, Count On Tools is an impressive manufacturing success story and a day well spent!  Thank you Curt, Rene, Zach and the Count on Tools team for your hospitality.

Frances Stewart is vice president for PCD&F/CIRCUITS ASSEMBLY.

Rethinking the Supply Line

The PCB fabrication industry is older than most of us still working. It is overdue for modernization. We have not seen transformational manufacturing changes in the PCB bare board industry during the past 15 years.

What we have seen is the installed capacity moved to China. It has been reported that 60% of global board fabrication now comes from mainland China or Taiwan. This move created a forced shift in how boards are purchased, and consequently created new demands in communication and logistics. Specifically, language, time zone, and cultural considerations. Bigger companies with China-based feet on the ground could adapt easily; the rest of us had to learn new skills.

I am suggesting that the rest of us modernize and rethink our supply line strategy.

Some may remember the evolution of the electronics component industry. First, component manufacturers sold directly to OEMs. Gradually, customers and component manufacturers found that a better path was through a local distributor. Arrow, Avnet, Future, DigiKey, and many others were born out of this efficiency. Today, it is an exception to buy directly from a component manufacturer.

PCB fabrication is difficult for distributors because every board is custom. Repeat: every board is custom. Custom equals high potential for error, which equals close technical review required.

So, buyers must go to China directly and slog through the variety of China sources. With this come the multiple challenges of accountability, communication, logistics and culture. The most dangerous of the challenges is having picked a supplier that occasionally (or often) sends subpar boards and provides no recourse or no response to your complaint. Do you really want to commit such a critical part of your BoM to the lowest China bidder?

The modernization of the PCB industry is not in processing, but in supply chain. A new category of value-added distributor is evolving in the same way the component distributor evolved … to make things easier. We call it “Managed Manufacturing Services.”

Think of it as a value-added distributor of printed circuit boards. This concept can greatly improve the supply chain for both customer and China manufacturer, but only if they really add value.

What are the important values, and how does this approach add value?

Technical support. The value-added distributor must be your expert design reviewer, capable of counseling you and quickly fixing the errors.

Only technically trained PCB teams really understand the manufacturability challenges of bare boards. With the technology of new IC packages pushing toward smaller geometries, new thinking is required about designing for manufacturability. So, your value added distributor has to be technically trained to provide this service.

Communication. The value-added distributor must be capable of clearly and cleanly communicating with a factory in a different country.

We have been working with offshore factories for a long time. We learned through hard knocks that developing a strong relationship with your counterpart in Asia is critical. I call it “Pitcher-Catcher.” Whether a fastball or a curveball, the two communicate in one cohesive motion. This takes time to develop and not every factory gets it.

Time zones can work to your advantage. We pitch everything to China by 5 pm Pacific and have answers at 6 am the next day. Your distributor must know the factory requirements well enough that only a few questions (EQs) come back, lessening the need for middle of the night conference calls.

Accountability. Your value-added distributor must have carefully vetted and audited the factories they use. They must be US corporations with financial accountability to their customers.

Slogging through a variety of factory options is not a good idea. Jumping from one to the next based on price and email pressure is also not a good idea. It wastes time and invites disastrous quality issues. Customers with little or no knowledge of what makes a solid factory are at particular risk. Yet most customers fall into this category.

If you have someone on staff with experience in this area, you can send them to China to visit multiple factories, but unless this person has in-depth knowledge of what makes the difference between okay and fantastic at the granular level, it is waste of $10,000. It takes deeply experienced people to see the difference. It takes board manufacturing experience.

From the China manufacturer’s side, it is just like the component manufacturers of old. It is much more efficient to deal with a small handful of companies who service the US market than it is to staff and service everyone. The culturally smart ones are beginning to see this and actually do view us as distributors for them. It is a proven supply-chain solution.

Following the model of the component distributors, we can modernize this PCB industry. We can improve efficiency, quickly adopt new technologies, and capture lower costs all by modernizing the supply chain. Welcome the value-added PCB distributor, or as we call it Managed Manufacturing Services.

Thomas Smiley is president, Precision PCBs; tsmiley@precisionpcbs.com.

Straightforward Explanation of MIL-I-46058C for Conformal Coatings

During your selection of conformal coating you ran in to a specification that you have seen before but not fully understood.  Conformal coating choices are vast, but with so many available, how does a user pick the correct one? Are there minimum standards that define what a conformal coating is supposed to do? Thankfully, yes there are. This column will focus on one such standard: MIL-I-46058C.

The official title for the specification is MIL-I-46058C, “Insulating Compound (For Coating Printed Circuit Assemblies).” The standard serves as a material standard, used to evaluate and document that a particular coating meets a list of specific performance attributes (more on those later). MIL-I-46058C was developed to define a uniform set of test methods and performance requirements for conformal coatings and gives users confidence that the material they select will perform.

MIL-I-46058C is managed by the Defense Logistics Agency (DLA).

DLA manages the standard and maintains the associated Qualified Products List (QPL). For a coating to be placed on (and stay on) the QPL, it must be tested annually by a DLA-certified laboratory. The data are reviewed annually by DLA to ensure that each coating proposed for inclusion on the QPL still meets the requirements of the standard. The latest version of the Qualified Products List is available from www.dscc.dla.mil.

MIL-I-46058C evaluates conformal coatings to an extensive list of properties. The tests are:

  1. Curing time and temperature: Coating must meet the requirements of the standard when cured according to the manufacturer’s instructions.
  2. Appearance: When cured per manufacturer’s instructions, coating should be smooth, homogenous, transparent, free of bubbles, pinholes, etc.
  3. Coating thickness: The recommended coating thickness shall be 1-3 mils for acrylic, urethane and epoxy coatings; 2-8 mils for silicone coatings; 0.5-0.7 mils for parylene coatings.
  4. Fungus resistance: The coating cannot support the growth of fungus.
  5. Insulation resistance: The average insulation resistance of all coated specimens shall be a minimum of 2.5 x 1012 ohms, with no specimens having a measured value below 1.5 x 1012 ohms.
  6. Dielectric withstanding voltage (DWV): Coated specimens subjected to 1500 VAC for 1 minute shall exhibit no disruptive electrical discharge (spark over, flashover or breakdown). The measured leakage current shall not exceed 10 microamperes.
  7. Q (Resonance): The resonance values for the coating, measured before and after immersion in DI water, must not change beyond specified limits.
  8. Thermal shock: Coating materials are subjected to 50 cycles of thermal shock. After thermal shock, coating must meet the Appearance and DWV requirements.
  9. Moisture resistance: The insulation resistance of the coating is measured under high temperature and humidity and must meet minimum specified values. After temperature / humidity exposure, the coating must meet the appearance, insulation resistance and DWV requirements.
  10. Flexibility: Coating is applied to a test substrate, cured per manufacturer’s instructions and bent 180° over a 0.0125” diameter mandrel. There shall be no evidence of cracking, crazing or adhesion loss of the coating.
  11. Hydrolytic stability: Coated specimens are subjected to four 28-day exposure of 85°C / 90% RH. After this exposure, the coating can show no evidence of softening, chalking, blistering, cracking, tackiness, adhesion loss or reversion to liquid state. The coating must also remain transparent enough to view nomenclature and color codes used to identify the components over which the coating is applied.
  12. Flame resistance: Coating shall be self-extinguishing and non-burning when subjected to a flame test.
  13. Shelf life: Coating must meet appearance, insulation resistance and DWV when tested after storage for six months at 25°C.

MIL-I-46058C was declared “inactive” in November 1998. This deactivation meant the standard was “inactive for new designs, except for replacement purposes.” This certainly does not mean MIL-I-46058C disappeared from the landscape. Today, MIL-I-46058C persists for coating users and specifiers due to its requirement for independent third party certification and remains the only published conformal coating standard with an associated QPL.

Caution!  As a user you have many choices of conformal coatings. Many materials claim to “meet the requirements’”of MIL-I-46058C. These are coatings have probably not been fully tested to the rigorous standard required to obtain and maintain MIL-I-46058C qualification. Treat these coatings with caution: “meets” does not mean “is” on the QPL. There is only one way to verify this and that’s through the DLA website.

The conformal coating selection process involves a check list of many variables. One of these variables is the need for MIL-I-46058C qualified coating. We hope that this article helps you understand not only how to find such a coating, but also what is behind this qualification.

Jeff Sargeant
www.humiseal.com

Simple Recipe to Avoid Conformal Coating Blush

Your conformal coating film is supposed to be clear and transparent, but it’s cloudy-white and dull … it’s blushing. This condition is an indication that your coating film is trying to tell you something, and it isn’t that it’s embarrassed.  This blog will help you better understand why your conformal coating film is blushing from acquired moisture contamination and help you eliminate this defect.

Coatings appear cloudy because they have inadvertently acquired moisture, either due to their hygroscopic nature or by artificial means (a cooling mechanism created by solvent evaporation), which then reacts negatively with the coating resin –  exhibiting itself as a milky, colloidal-type substance.  Many different types of conformal coating chemistries can be sensitive to blushing under certain circumstances.  These circumstances are usually related to specific ambient conditions, application, cure, condition of the assembly/substrate/associated components, storage environment and/or equipment under use.

blush-conformal-coating-example

These conditions include:

  • High humidity, ~70% or higher
  • Low (or cooling) temperatures, ~16oC or below
  • Assemblies and associated components exposed to ambient moisture during storage prior to coating, can significantly increases the chance of blushing.  To overcome this, baking is often recommended. Not baking your boards after cleaning is a prime source of moisture uptake into assemblies
  • Storage conditions (opened containers, inside pressure pot, RH resident in the charging gas of the application equipment) and interaction with moisture already on the assembly.

blush-conformal-coating-example-1

In conjunction with this variety of circumstances, certain solvent-borne chemistries can aggravate this condition due to the fast evaporation of internal solvents.  This creates a cooling mechanism as they volatize from the film.  This cooling mechanism will condense any moisture vapor that may be present in the immediate atmospheric area.

High solids, low volatile room temperature vulcanized, or UV conformal coatings (with secondary moisture cure functionality) may also show some degree of “blush.” They are more sensitive, possibly hygroscopic, to the presence of ambient moisture vapor as this is utilized to activate their primary or secondary curing mechanisms.

Problems that can be created due to moisture vapor intrusion/blushing:

  • Surface tackiness/incomplete cure
  • Below standard aesthetic quality
    • Coating discoloration
    • Poor gloss retention
  • Poor adhesion
  • Wrinkling during second coat application/over-coating.

Here are some simple steps to start with … DIY:

  • Maintain nominal ambient humidity in the production environment between 45% and 65%.
  • Maintain nominal ambient temperature in the production environment between 18oC and 27o
  • Increasing the flash time between coating application and cure may help, as moisture vapor in the wet film may have the potential to re-evaporate
  • Use different thinner to change evaporation rate.
  • Use desiccated air/nitrogen to push coating through applicator
  • Post-bake assemblies after aqueous wash (if applicable) to eliminate any entrapped (under or between components) moisture.
  • Ensure that all partial containers are properly sealed when stored. Nitrogen purge in partially used container helps to eliminate moisture.

We hope that this helped you understand what blushing is, how it occurs, and how to prevent/alleviate it from occurring.  Remember that moisture is the root cause of cloudy or blushing conformal coating.  With many potential sources of moisture contamination, following our simple recipe will lead you back to a crisp, clear, and transparent film, and zero defects.

Nick Naumovic

www.humiseal.com