Quality in the components: How a single capacitor or process can make a HUGE difference.

-Deacon Wardlow

It’s the little things in life which can make a huge difference. Reaching into your pocket and finding a dime which makes for exact change at the coffee shop or being glad you paid that little extra to buy the nicer watch which has lasted for years when others have long been retired to the back of the catch-all drawer. Over time, electronic components have become more versatile, more reliable and cheaper. The difference between a high-end and a low-end capacitor can be a few pennies. It doesn't seem like much, but those pennies make a big difference to a manufacturer who buys hundreds of thousands of them.

if you’ve ever had to run a home DIY project, you’ve gone to the hardware store and picked out the bits and pieces you needed. Maybe you noticed a few different types of nails and you buy a bunch of the cheaper ones to save a few dollars on a project that is already going over budget. If you’ve been there, you’ve probably also noticed how those cheaper nails bent, wouldn’t go in easily, and (in many cases) just didn’t get the job done. You go back and spend a few dollars more and find the slightly more expensive nails really made a difference. The same thing occurs in manufacturing.

A manufacturer will look at the overall performance and the failure rate of a component. Component X costs 5 cents less than Component Y, but it’s prone to a 5% higher failure rate. The manufacturer looks at how many they’re buying, how important to the performance of the system that component is, and will decide whether it’s worth the cost savings to put the cheaper component in and put up with a few RMA replacements vs. the greater expense of the more reliable (and costly) unit.

How much attention to detail is paid by the manufacturer of choice? You have to ask them. How do they source their parts? How much of a failure tolerance does the manufacturer have? When they look at processes which could extend the lifetime optimal performance of the system (for example, conformal coating on power supplies), do they see the value added for the end-user or do they see an expense they don’t want to be burdened with?

When a manufacturer is pinching pennies, it doesn’t always mean those savings are passed along to you. They likely sell the same system at the same price (and often a higher cost) than the competition and you’re stuck playing a game of chance to see if the components will function for the projected lifetime of the system or if “Warranty Deadline” day comes and goes and things start falling apart well before their time.

Make sure you’re being told, up front, what really goes into the system you’re investing in. Make sure neither you, nor the manufacturer are saving a few pennies now which will cost a lot of dollars to fix later. Usually the axiom “penny saved is a penny earned,” is a good one. In this case, the manufacturer reaps rewards and the buyer ends up with the risk. You’re investing in them by choosing the manufacturer as a partner, make sure they’re making the right decisions to ensure your investment and trust are well placed.

*I invite you to comment here and/or email me directly with requests at deacon@vantageled.com. Vantage LED has white paper resources and more educational material on the website (http://www.vantageled.com), please check it out when you have a moment. Note all posts/thoughts/writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED’s beliefs, attitudes, thoughts, etc. unless specifically stated.

LED Sign 101: Hidden Costs /Issues/What to look for to Identify Quality vs Cheap Components

-Deacon Wardlow

Technology can get very complicated. Once upon a time, it was enough to ask what LED a manufacturer was using for their LED Sign systems, the LED used would be a general qualifier to demonstrate if the manufacturer is using high-end components or cutting corners. With the release of patent-rights with LEDs and improvement of automated systems, this qualifier isn’t enough. It can feel like you need a Doctorate to wade through the technical terms. Have no fear, the “Geek Speak” team is here to help you through.

System specifications are a great place to start your qualification.

Colors:
Start with the number on Colors (you can find the original blog here). It used to be 16.7 Million colors was good, billions was better. Most control systems are now low enough (cost-wise) to allow manufacturers to go high-end without heavy costs required pushing the numbers up to Trillions. The higher the true color value available the better. Higher color values are an indication of higher overall depth of color and overall system performance. Lower values are an indicator the manufacturer is cutting a corner to achieve a lower cost (a few dollars here and there add up in the long run for a manufacturer, but the corner cut means a lower-performing system which will not be ideal for the long term investment being made).

Power Supplies:
I wrote a blog a few months back on this topic. Not only is the type of power supply critically important, but how the manufacturer is driving the power matters as well. Many manufacturers will drive power supplies at about 70-80%. This doesn’t sound bad to most people (they’re using less than 100% right? That’s gotta be good…). Unfortunately, the power supply performance is based on temperature. The hotter a power supply gets, the lower its performance capability. Optimally, a manufacturer should only be drawing upon 50%-60% or less of the power supply’s available power. This ensures the power supply will perform optimally regardless of high temperatures/environment. If a power supply is driven at 80%, the moment heat rises above 85 degrees, the system performance starts dropping. If the power supplies are driven at high values (70-80%) the moment performance drops below the 70/80% mark, the power supply will shut down and cause the system to go blank.

Conformal Coating:
Conformal Coating is incredibly important for the long-term optimal performance of an LED system. Further details are available in a prior blog written last month. When you look at the green PCB (Printed Circuit Board) on the back of an LED module, you’ll see a glossy shine. This should be even without clumps and dull/matte areas. Conformal coating protect sensitive components from oxidation, break-down, and damage from the environment. Poor conformal coating will cut the lifetime performance and expectation on a system down to a third or less.

FPS (Frames Per Second):
Another indicator to check the quality of the controller is refresh rate and FPS. Low values indicate a lower quality system. Baseline FPS should be 40-60 (not lower than 40) with a refresh rate of 1200+Hz). LED Signage is a big investment which will run returns over a decade. While cutting costs with a cheaper controller may appear good in the beginning, the overall performance takes a hit.
 
Hidden Costs:
Conformal coating on power supplies, adding a more robust capacitance to circuit boards, higher-grade chips, etc. are all small incidental costs which add up. Many manufacturers avoid higher-end components figuring the end-user won’t know any better and the performance is still “ok.” Not using proper conformal coating leads to shorter lifetime performance for system critical components which will require replacement.

While these seem like small things, the details are important. When looking at a low-cost alternative or dealing with a manufacturer who carries a second, “cost effective” line, make sure you get a full explanation of how that lower cost is achieved. The money the manufacturers saved by not using the best process or product ends-up costing the end-user with premature service calls (which can cost hundreds of dollars a visit) and it can cost the dealer their hard earned reputation as a reliable source for quality solutions. Cutting corners may appear to save some money up front, but will cost in the long term.

*I invite you to comment here and/or email me directly with requests at deacon@vantageled.com. Vantage LED has white paper resources and more educational material on the website (http://www.vantageled.com), please check it out when you have a moment. Note all posts/thoughts/writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED’s beliefs, attitudes, thoughts, etc. unless specifically stated.

LED Sign Killers: Heat & how to protect against it.

-Deacon Wardlow

Heat can kill your display’s performance and longevity. High heat can shorten the lifetime of LEDs and decrease the performance of the system overall.

Heat buildup in the system can be resolved with a series of engineered solutions. Thermostatic fans, proper conformal coating, thermal management of the systems, and overall engineering should ensure the system not only distributes and pulls heat away from critical components (Power Supplies and LEDs) but also keeps the system performing optimally throughout its lifetime.

Thermostatic Fans:
Thermal switches placed with high-grade industrial fans are a key component for increasing the longevity of the fan and ensuring the best-use of vented cooling on a system. The thermal switch should be preset at certain thresholds to ensure fans only run when additional venting/cooling is required to keep your LED message center running at its best. This reduces wear and (eventual) part replacement cost to the end user and keeps the fans lasting as long as the full sign system; circulating air through the system to avoid heat buildup.

Thermal Management:
Each and every cabinet should be forward-engineered for optimal heat management. Components need to be carefully laid out in the initial design stage to ensure heat is evenly displaced throughout the cabinet and air flow is optimized to avoid any thermal buildup.

Conformal Coating Controls:
Conformal Coating of components (see my previous blog article and the Vantage LED white paper on power supplies) should be carefully controlled in the build-phase for LED modules and circuit boards. Different PCBs (Printed Circuit Boards) have different coating requirements. Matching the CTE (Coefficient of Thermal Expansion) to the PCB ensures the right amount of coating for the different components. CTE is volume-dependent and the thicker the coating, the greater the likelihood these changes can cause heat buildup in a system which can damage heat-sensitive components (like LEDs).

Conformal Coating materials:
Materials need to be carefully evaluated to ensure the right material is matched with the coated surface. A material like silicone can have a high CTE and low modulus (expansion or compressive forces). As a result, silicones in general do not cause significant stresses on sensitive components. On the other hand, silicones trap heat and could cause other issues (see previous blog article on silicone coating). Urethanes and epoxies have been historically high modulus materials and don’t have as many heat problems. Thus it's important to understand why the manufacturer chose the coating type and they are able to justify their choice.

It’s important to ensure every step and stage of the build process is monitored for quality control. From initial engineered concept to completed component/system, the build line needs to be  carefully controlled to ensure the highest quality components, protection and engineering is utilized. The result, a system which performs optimally regardless of the heat and environment its placed in.


* Always feel free to comment here and/or email me directly with requests at deacon@vantageled.com. Vantage has white paper resources and more educational material on the website (http://www.vantageled.com), please check it out when you have a moment. Advertisements/promotion for your business and inappropriate comments will be deleted.. Thank you!

**Note all posts/thoughts/writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED’s beliefs, attitudes, thoughts, etc. unless specifically stated.

Conformal Coating; check if they're doing it right.

Fig. 1 - example of moisture permeation

-Deacon Wardlow

Conformal coating on PCBs (Printed Circuit Boards) is a must for proper protection of your investment with an LED Sign (or any digital signage system components exposed to the elements).  Conformal coating is a thin polymeric layer which “conforms” to the exposed face of the printed circuit board and its components. Conformal coating acts as an insulator, protecting the circuitry and components against shorts and contact with moisture and other contaminants. It also provides mechanical protection from vibration and thermal shock.

Conformally Coated PCBs aren’t enough, the type of coating used and how it’s applied is just as important. Improper conformal coating can cause as many issues if improperly selected and applied. Selecting the appropriate coating and application reduces the risk of failure.

Moisture permeability has to be considered when choosing the right coating compound. Coatings are porous, so water and other materials permeate to varying degrees and cause failures. In Figure 1, solvent-based urethane allowed enough moisture permeation which caused corrosion underneath the coating. Some types of coatings are more permeable to moisture than others.

Though moisture permeation causes issues, permeability to moisture can also be an advantage. A coating which allows a board to “breath” creates a low static moisture level and trapped moisture can be a problem; one standard recommends baking a PCB for a minimum of 4 hours at 93+/- 5.5 ºC before conformally coating. Manufacturers which skip the cooling step or choose the wrong compound can expose your investment to serious issues.

Major issues to watch for with conformal coating compounds:

Shelf Life of the compound is often overlooked; a manufacturer can have the right coating but end up using product which is no longer at its prime. How often is the conformal coating used/replaced? Is the shelf-life of the product taken into consideration and old coatings replaced periodically to ensure optimal performance?

Uncured coating can result from the inability for a coating to obtain the optimum properties at the manufacturer’s specified time and temperature. Coatings can be inhibited by contaminants such as organic acids from flux residues. In the case of natural latex (a common masking agent), the residue alkali can reduce curing of certain catalytic-type coatings.

Adherance to the surface is critical for a coating. Since most coatings are liquids, the coating must be thick enough that it remains on the PCB surface as a uniform film but not too thick or have too high a surface tension to cause voids (liquid coating application is commonly referred to as “wetting”). This wetting is influenced by changes in the composition of the coating and compatibility with the PCB surfaces (solder masking, board or component surfaces, potting compounds, etc.). Wetting results in “spotting” and areas on the PCB which are flat/dull compared to the rest of the board/coated material.

When you’re looking at manufacturers of LED Message Centers, ensure they pay attention to the details. Many will claim to do conformal coating, but what steps have they taken to qualify the coating is done properly? Don’t accept a “standard” answer, dig below the surface to expose the truth.


* Always feel free to comment here and/or email me directly with requests at deacon@vantageled.com. Vantage has white paper resources and more educational material on the website (http://www.vantageled.com), please check it out when you have a moment. Advertisements/promotion for your business and inappropriate comments will be deleted.. Thank you!

**Note all posts/thoughts/writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED’s beliefs, attitudes, thoughts, etc. unless specifically stated.