Military applications often push technologies to their limits. Applications such as electronic warfare (EW), radar, communications, and surveillance have made demands on RF/microwave technologies over the years. Levels of integration have increased with growing demands for greater packaging densities and reduced weight, and increased reliability over a wider range of operational parameters (such as wider temperature ranges, increased thermal rates of change, greater ranges of vibration and longer storage in field conditions at the point of deployment).
One of the challenges most unique to military and aerospace electronics is the high value of and length of service expected of these assemblies, often being 20-30 years. During the program life, the electronics are likely to be periodically repaired, refurbished and upgraded. Therefore, the degree of reworkability of the coating material needs to be thoroughly evaluated and the reliability of repair solutions thoroughly evaluated.
These electronic assemblies continue to become an increasingly sophisticated and important aspect of both the functionality and reliability of modern military and aerospace systems. The costs of failure, both in direct fiscal cost and especially the loss of highly trained personnel and civilian casualties are extremely high, and so it is extremely important that these systems function exactly as required, when required, for the entire duration of the program. Conformal coating is one of the main mitigation solutions, preventing degradation to the assembly from the external environment.
Although not subjected to Pb-Free production, the reality is that many commercial components are supplied with a pure tin finish (Lead-free compliant) to preserve solderability. There has recently been much concern about the potential for tin whisker growth, as a potential failure mechanism, due to the long service lifetimes and extreme operating environments encountered in military/aerospace electronics (http://nepp.nasa.gov/whisker/background/). The use of the correct conformal coating has been shown to be an effective mitigation strategy against the formation of these whiskers
HumiSeal offers the industry’s widest range of high performance coatings, formulated from the widest range of chemistries and able to be applied by any of the common application methodologies, enabling you to select the product that best meets your project needs, production throughput , floor space and capital equipment requirements, whether you are upgrading an existing product, transferring a production process from another facility or are working on a new product introduction.
In addition, with more than 50 years experience, and a wealth of clients that produce similar products, have similar end-use environments or have overcome similar challenges, HumiSeal is well placed to offer valuable advice that can help save time or reduce the effort to achieve an optimal solution.
HumiSeal’s central philosophy is that a conformal coating is not simply a material, it is part of a process, and all of HumiSeal’s materials are backed by an unparalleled level of process knowledge and applications experience, to ensure that whatever your process requirements, a perfectly tailored total process solution is available to ensure the results that you demand.
The overall consistency of your process is largely governed by the consistency of the process inputs, of which your conformal coating material is one input. HumiSeal go to very great lengths to ensure the consistency of batch-to-batch material characteristics. Take advantage of one of our pre-blended materials, to virtually eliminate any potential for on-site mixing or measuring mistakes and you can be assured of an industry beating level of consistent material inputs, to take you one step closer to your SPC or 6σ Key Performance Indicators (KPIs).
With even the best process solution, occasionally things change, usually through no fault of the production-engineering department. Should this happen to your line, you can rest assured, wherever your factory is located, that HumiSeal’s team of Global Application Experts are on call to ensure that you resolve the situation to your complete satisfaction in the shortest time-frame possible and get your process running at optimum efficiency once again.
Designing quality into your product begins with understanding your products lifecycle and end use operating environment. HumiSeal will work with you from project inception, to understand these key parameters and deliver a material solution that will enable you to exceed the level of quality and reliability that you require, and work closely with you during all stages of your project, from Design, Prototype, Pre-Production Process Qualification data-driven studies and through to mass production, ensuring you are getting the quality levels you expect.
All HumiSeal materials offered to the Industrial Controls industry exceed the requirements of all relevant specifications and or standards to ensure they exceed the required levels of protective performance for your application. With over 50 years of experience, and a wealth of clients in similar situations and similar end use environments, HumiSeal is well positioned to offer solutions based on the firm basis of this wealth of experience.
HumiSeal materials are manufactured in world-class, state of the art facilities, using computer-controlled, automated processes wherever possible to minimize the potential for human error. When automation is not possible or practical, Poke Yoke systems are used to further reduce the risk for errors. HumiSeal actively uses a combination of FMEA, SPC and other 6σ tools to ensure the quality of its products from this manufacturing process, and batch characterization of key parameters as a final check. HumiSeal uses lean principles wherever possible and Kaizen Continuous Improvement methodologies to spot and reduce waste, as well as ensure the highest quality outputs are produced for our customers.
By ensuring you have the highest standards of incoming material quality and consistency, HumiSeal takes you one step closer to your In Process Key Performance Indicators and first-pass yields etc. However, the conformal coating material is but one-input into your overall coating process. Other factors will affect your in process quality, including the level of cleanliness of your assembly, presence of residues from soldering operations, and maintenance/set-up of your application equipment amongst others. HumiSeal process experts are always on hand to assist with all aspects of in process quality assurance to ensure your process meets your organizational goals. The following interactive tool is helpful for diagnosing common production defects and offers suggestions on root cause corrective actions.
By ensuring you have the highest quality inputs (performance, & consistency) and ensuring your process is running under control and exceeding the required level of workmanship, you have taken great strides towards ensuring and protecting the reliability of your electronic assemblies. However, from time to time, field failures may still occur and should this happen, then you can rest assured that the HumiSeal Process Experts are equipped to help you diagnose the failure’s root cause and associated corrective actions using an 8D problem solving methodology.
Design Engineering plays a crucial role in the overall reliability of a product produced, both in terms of the inherent robustness of circuit board layout and often times the qualification and selection of materials used for fabrication. Design engineers should be mindful of the expected operating environment of the assembly from the inception of the design, since if it is likely that conformal coating will or even maybe required, designing the product with this in mind can save many production headaches.
In general there are 3 types of areas to consider in designing for the conformal coating process; Definite areas and components that MUST be coated, definite areas that definitely MUST NOT be coated (e.g. connectors, thermal transfer or heatsinks), and areas that MAY or MAY not prove to need coating. The designer should aim to keep the maximum spacing between an area that is known to require coating and one that is a definite coating free area. In a perfect world, all of the coating free areas and tall components would be kept to one edge of an assembly to aid the conformal coating process. However, there are of course other challenges relating not least to where the component will be situated and how it will interconnect with other components that may preclude this.
HumiSeal can help prospective designers at the outset of a project, by helping to decide the likely coating material choices and discussing application behavior and methodology in light of any constraints. Designing for conformal coating can ease production, raise overall quality levels and improve the long-term reliability of a design, as well as minimizing production costs.