INTRODUCTION
It is often the accepted practice for the E3 engineer on a program simply to provide his technical expertise on meeting EMI, EMC, EMP and other E3 requirements and to let others take the recommendations from there. Once the analysis and recommendations are complete, the decisions on how to implement the design are up to the platform design team.
The truth be told, this approach has sometimes resulted in sound approaches getting “lost in the shuffle.” E3 requirements are just one of many requirements and priorities, all competing for limited funds and schedule. To be effective, one must be able to advocate his recommendations to the program as the best value solution and to become skilled at being a good teammate and evaluator of other program priorities. E3 engineering does not stop at CDR! It is an integral part of the entire system lifecycle.
BECOME PROFICIENT IN PROVIDING THE BEST VALUE TO YOUR PROJECT
In my 27 years in the Electromagnetic Environmental Effects field, I have seen more than my share of great E3 solutions go by the wayside because the E3 engineer did not follow the design through implementation. Without diligence on the part of the E3 engineer, a project team can come to view E3 hardening of a product as something that adds no intrinsic value; it just adds cost, weight, time to the schedule, etc. More and more project teams are faced with deciding which discipline(s) get how much of the limited resources available to achieve compliance—E3 is just one of many requirements that have to be met. And, in most cases, the product will probably be able to operate and function properly to the untrained eye whether it meets its E3 requirements or not. This fact can make E3 design engineering particularly challenging.
To become a good advocate, one needs to work on developing a variety of skills other than just good E3 engineering skills. One needs to be competent at relaying justification for solutions in terms that the rest of the project team can understand. That means being flexible while still staying focused on the end goal of compliance. More now than ever, an E3 engineer needs to be a good evaluator of a solution that would provide the “best value” to the program; that is, the solution that provides the “best bang for the buck.” Finally, good team dynamics and persistence are critical.
KEYS TO BECOMING A GOOD E3 ADVOCATE
Investigate All Practical Solutions
With today’s emphasis on cost effectiveness, maintainability, reliability, etc., just relying on the old “tried and true” solutions is not enough to meet most project requirements . The effective E3 engineer must become proactive about researching all practical solutions and must find a way of quickly honing in on a “best value” solution while still complying with the technical requirements.
This process should begin by not accepting what seem to be design limitations at face value and continuing to think “out of the box.” For example, engineers tell you that because of severe weight limitations, they cannot shield a particular subsystem. To that engineer, the only way he has seen systems shielded is through the use of aluminum. In truth, you may be able to use a lightweight conductive composite to shield your subsystem and still allow the weight restriction to be met. You can further highlight the low cost and maintenance features of the composite. The more options you have in your arsenal, the better you will be able to solve complex E3 problems.
To do this, you need to stay on top of the latest design solutions available from the E3 industry. Innovative solutions to complex problems are constantly being created, as evidenced in the substantial improvement in E3 materials and methods discovered and refined in the last 20 years. You can’t use a new composite or gasket material unless you are aware of it, so take time to read your EMI journals and to attend those yearly conferences so that you can continue to offer your superior E3 solutions.
Finally, you need to advocate your solutions, not just present them as “options.” You are the E3 “guru,” and your team is depending on you to sell them on a best value solution. By (inadvertently) transferring this function to others, you allow them to assign their own priorities to your proposed solution and to decide on options that may or may not provide the project with the optimum E3 protection. For example, a project manager who is new to project requirements may think that using inexpensive fingerstock on your heavily used EMI door is a great solution—you will pass your EMI test without breaking the bank. Usually by the time the fingers start breaking off, the responsibility for dealing with the resulting problem will be in the hands of others. In this case, it is YOUR job to think long-term and to advocate a more maintainable solution during the design phase.
Educate Your Teammates on E3 Early
Just as you need to understand what concerns and priorities drive your project, your project team needs to understand your concerns and priorities. Take the time to educate them on why E3 is important to your customer and on how compliance is achievable if the right approach is taken. A team that understands early in the project what E3 design features need to be implemented generally has less trouble implementing them in the overall design. If everyone is getting the bonding/shielding/grounding message at the beginning, it will become part of their design mindset, making your job easier. Something as simple as a lunchtime “brownbag” presentation at the beginning of the project on how E3 fits into the overall requirements can be very effective in stopping complaints later that they didn’t know what they needed to do to meet E3 requirements!
Determine the Solution That Provides the Best Value, Then Sell It
As the E3 representative on a project, your teammates will justifiably expect you as the “E3 Guru” to propose a “best value” solution that not only meets the E3 requirement but that also takes other project priorities into consideration. With pressures to decrease cycle time ever present, it is important that you learn of the project priorities and incorporate them into your INITIAL solution proposal, if at all possible. As a minimum, you should consider:
• Performance. Does your solution meet the E3 requirement? Is there adequate design margin? When possible, press vendors for actual test data and be mindful of the test conditions used—they may or may not match your test conditions. For example, a wire mesh gasket may provide excellent shielding when compressed once, but may drastically degrade after 50 compressions.
• Maintenance. Will your solution continue to perform after being subject to its specified environment? What sort of degradation does it suffer when subject to its environment over what period of time? This is not something vendors typically showcase, so you may need to do some digging to find answers to this one. Many times, simply passing a test before delivery is no longer adequate for meeting requirements. For example, if you are planning to use a “sacrificial anode” grounding scheme for your field deployed shelter, determine how often and how much trouble it will be to replace the ground rod and document that fact EARLY in the program
• Cost/schedule tradeoffs. What are the short- and long-term costs of your solution? Be prepared to offer your project design team alternatives, lest they come up with some (less desirable) alternatives of their own. If you plan to place a large order to meet program requirements, let your vendor know this so that the team can get cost and schedule priority. Do your research so that you know what you need and where you can afford to be flexible . When ordering through a parts and materials group, be specific about what you need and why. Otherwise, you could end up with a low cost “equivalent” that ultimately does not meet your needs. For example, NEVER just specify that the mating surfaces on a bonding bar on your shielded enclosure have a “conductive finish” when what you really need is a class III nickel-plated mating surface. Your purchasing representative’s specialty is getting the specified product at the best price and still meeting delivery, so it is not realistic to expect that he will be able to make the E3 decisions that rightfully should be made at your level.
• Impacts to other disciplines. It is likely that at some point in your career that E3 priorities may conflict with that of other disciplines such as environmental, reliability, safety, etc. It is critical that you be proactive early in the project to find out if there are any potential conflicts and to work quickly to resolve them. Inaction could result in a less than desirable E3 solution. For example, if the case that you are working with has a requirement to be airtight, take the time early in the program to locate an EMI gasket that can provide an airtight seal. Don’t force the customer to decide which of his requirements is more important—he is expecting you to find a unique solution that will allow him to meet both requirements in a timely manner. Waiting around until this becomes an issue should not be an option—work with your teammates in other disciplines!
• Be there for the long term. Keep the scope of your role broad. Limiting your role on a project to just someone who provides E3 guidance, then waits for a finished product to test is severely limiting your design influence. Many project design aspects affect and are affected by E3 design in ways that are rarely obvious in the early stages. Make an effort to stay involved with the project design philosophy so that you can ask questions early and can anticipate impacts to your E3 design. I was on a project years ago when I heard rumblings that upset problems occurred on some of the computers in one of our shelters when they initially powered on other shelter components. After some investigation, the problem turned out to be rooted in the 100- dB TEMPEST filter, which our team redesigned to have less inductance in time to meet the original delivery milestone.
• Follow up with your proposed solutions. The phrase “the devil is in the details” rings particularly true in the area of solution implementation. Engineers who have little E3 experience are not in a position to implement your approaches, and therefore develop well-intentioned but ultimately inadequate ways of adapting your solution to their design. In particular, I have witnessed a number of innovative “bonding” techniques between conductive surfaces which have proven to be less than optimal! Take time to discuss solution implementation with your engineers, and then review the finished product before going on to the next step. Scheduling appropriate subsystem tests/checks is a good mechanism to accomplish this goal.
• Stay involved through all phases of the project life cycle. Your E3 effort should not end once a product is delivered. I have seen my share of well-designed systems pass E3 requirements during First Article Testing, only to see them experience serious EMC problems a year down the road. Persuade your project team to allow you to stay part of the team, even if in a peripheral role, to ensure that E3 solutions are adequately maintained and remain effective. Over time, gaskets compress, fingerstock breaks, bonded surfaces weather, and system modifications occur. Without some level of monitoring and maintenance, most E3 protection will degrade over time. Door gaskets need cleaning, gaps start to form, fingerstock fingers break, fittings need to be tightened, and bonding between mating surfaces needs to be tested. Scheduling E3 maintenance into your post-delivery milestones is an excellent way to maintain E3 effectiveness.
CONCLUSION
To stay effective, an E3 engineer needs to be more proactive than ever to meet the challenges of making systems “smaller, faster, cheaper.” This effort includes working early to educate other members of your design team and continuing to work closely with them through all phases of the system life cycle. Stop being just an E3 engineer—become an E3 advocate!
Woodrow T. Hawthorne is an EMI/EMC/EMP design engineer for the Avionics Group at Northrop Grumman Integrated Systems (NGIS) in Melbourne, FL. Mr. Hawthorne has 27 years of experience in E3, TEMPEST, and nuclear effects analysis and design. He holds a Bachelor of Science degree in physics and mathematics from the College of William and Mary and has been a NARTE-certified EMC engineer since 1990.
