As most people are aware, metals serve as excellent conductors of electricity, while non-metals (such as plastics and rubbers) do not. Electrical conductivity—or lack thereof—make these two types of materials generally suited for different use cases in the industrial sector. When choosing a manufacturing material for an electrical or electronic device, it is important to consider its electrical properties, including its conductivity, to ensure the end product functions as intended.
The following blog post serves as a guide to electrically conductive materials, outlining what causes their key property, the types available, how they relate to manufacturing, and how to turn a typically non-conductive material into a conductive one.
What Causes Electrical Conductivity?
Manufacturing materials vary in the number (one to eight) of valence electrons present in the outer shell of their atoms. In general, the lower the number, the more conductive the material (usually a conductor) and, the higher the number, the less conductive the material (usually an insulator).
Most metals have between one to three valence electrons, which allows the electrically charged subatomic particles to dislodge and mobilize easily. The free movement of electrons results in the passing of a charge—i.e., the conduction of electricity. In contrast, rubber and plastic materials typically have few, if any, free electrons, making them poor electrical conductors but excellently suited for insulating applications.
Examples of Electrically Conductive Materials
Many of the most highly conductive materials are metals. The three metals with the highest electrical conductivity are:
Each of these metals has one valence electron. Aluminum is the next most conductive metal, despite having three valence electrons. Although silver and gold offer greater conductivity than copper and aluminum, respectively, the latter materials are more commonly used due to their lower cost and broader availability.
The Impact of Electrical Conductivity on Manufacturing
The electrical properties of a material influence how it is used in electrical and electronic devices. For example:
- Conductors—highly conductive materials (e.g., metals such as silver, gold, or copper)—are used for manufacturing electrical wires and cables
- Insulators—materials with poor electrical conductivity (e.g., rubber or plastic)—are used for making insulation and other electrical protection products
- Semiconductors—materials that are neither good nor bad conductors of electricity (e.g., silicon)—are widely used to make integrated circuits for computers, phones, TVs and many other electronic devices
How to Make Non-Conductive Materials Conductive
As an alternative to metals, product manufacturing companies may also use a typically non-conductive material, such as a fabric or elastomer, that has been altered to have enhanced electrical conductivity. Material manufacturers can convert a non-conductive substrate into an electric conductor by employing a specialized technique that integrates electrically conductive additives into the base material.
Electrically Conductive Products From RCF Technologies
At RCF Technologies, we leverage our proprietary material—Rishon®—to create a wide range of electrically conductive products, such as couplings and seals. Although Rishon is naturally non-conductive, we can incorporate minute quantities of additives that enhance its conductivity without increasing its weight. To learn more about our electrically conductive products, contact us today.
Choosing Seals and Gaskets
Choosing Seals and Gaskets
Features – Reference Guide
Selecting the right partner is the first step in obtaining proper seals and gaskets for each application, ensuring better performance and longer life.
December 3, 2019
By Paulie Rose
Seals and gaskets must perform in some of the most challenging aircraft conditions, solving high temperature, flame retardance, corrosive fluids, or extreme pressure challenges. Knowing which seal or gasket best addresses the need is paramount, and a trusted partner can identify products such as:
A radial seal with rectangular cross-section that will outlast and outperform the standard radial seal for more fly time and revenue
A gasket with single-fastener access that maintains a firewall barrier to save hundreds of hours in labor during installation
A seal that can be vulcanized directly to metal with no adhesive that might burn off, eliminating fasteners
A fireproof gasket allowing each wire bundle to have single fastener access will save hundreds of hours (and dollars) in labor during installation.
Rishon material bonds to all metals and most composites using the parent material in the B stage as the adhesive. Vulcanization can be achieved in 3 minutes at 300ºF with no clean up, no adhesives, and no humidity requirements.
Understanding each application’s requirements, conditions, and related factors is crucial to selecting the appropriate seal and gasket for the job. Engineers and designers partnering with a manufacturer can develop a customized solution, selecting the appropriate materials in the proper lay-ups and configurations to successfully meet project needs.
A manufacturing partner should be knowledgeable about the aerospace industry, have strong research and development (R&D) capabilities, a robust engineering department, and a proven history of success.
A manufacturer must be appropriately certified, understand the importance of industry technical specifications, and willing and able to meet ever-evolving needs by taking advantage of new technologies.
Strong R&D and engineering departments are critical to partnering with an OEM to create customized solutions. As the industry pushes to create more cost effective, fuel efficient, sustainable aircraft, manufacturers must respond and be ready with solutions that meet those needs.
A tailor-made solution for an aviation project can take many months (even years) to create. From the first inquiry to final production, many conversations, meetings, and revisions will likely occur, and knowing that a partner will see it through to the end offers reassurance for the substantial investment of time, energy, and dollars.
Seals and gaskets can be made from plastics, metals, or rubber for extreme conditions, but those made from certain composites and/or metal will outperform standard ones. Seals and gaskets made from RCF Rishon material outperform other elastomeric seals and gaskets, offering:
*-170°F to 850°F (-112.2°C to 454.4°C) working temp. range to continuously meet Advisory Circular 20-135 criteria for 15 minutes of direct contact with a 2,000°F (1,093.3°C) flame with no backside penetration
*Bonding to all metals and most composites using the parent material in the B stage as the adhesive, achieving vulcanization in 3 minutes at 300°F without clean up, adhesives, or humidity requirements
*Degradation resistance in chemical environments ranging from Skydrol to jet fuels to diesel fluid
*Heat and/or flame insulation in thicknesses as low as 0.050″
*Inherent non-conductivity, but able to become electrically conductive while remaining flexible with almost no added weight
Transplanted Californian: Dianne Zimnavoda, president of RCF Technologies, moved her company from Los Angeles to Vidalia.
The flying robot invasion has already begun. Lethal, battle-tested drones (unmanned aviation vehicles or UAVs) are being used in Pakistan, and the military wants more of them. Selected universities, law enforcement agencies and aerospace firms currently are operating UAVs in limited domestic airspace.
And in a few years, through federal coercion, more robots will be sharing the friendly skies over your neighborhood with passenger planes and other traditional aircraft.
All of which could ensure a lucrative future for an already soaring aerospace industry in Georgia. Last year, Georgia’s worldwide aerospace exports topped $5.75 billion – fourth highest in the U.S.
“It is an industry that definitely keeps me busy,” says Steve Justice, director of the Georgia Center of Innovation (COI) for Aerospace, which operates under the Georgia Department of Economic Development (GDEcD). “We’ve got 500 companies spread out all over the state, and it’s so geographically diverse, it’s sometimes hard for people to get a handle on it.”
An engineer by training, Justice has worked for some of Georgia’s blockbuster aerospace and aviation companies throughout his career. Today, he is Georgia’s aerospace guy, so his boss, GDEcD Commissioner Chris Cummiskey, depends on Justice and the COI to, “think ahead, look for new ideas.
“We want to keep focusing on what the next major movement in aerospace is,” Cummiskey says.
Congress gave a pretty good hint of at least one of the next major movements in February, when it passed a law requiring the Federal Aviation Administration (FAA) to open national airspace by late 2015 to civil and commercial UAVs. Leading up to that, the FAA is going to designate six UAV test sites around the country, and states are lining up for the opportunity.
“There’s a lot of potential for Georgia, and there are a lot of people running the numbers right now on how much economic activity might result,” says Lora Weiss, lab chief scientist at the Georgia Tech Research Institute (GTRI), one of the leading brain-centers in the development of fully autonomous (or pilotless) UAVs for the Department of Defense – actual flying robots that think for themselves, can communicate with other autonomous robots (in the air or on the ground) to spy, hunt, kill, whatever.
Georgia Tech, along with Middle Georgia College and state industry leaders like Justice, are part of a public and private collection of entities pitching the FAA this summer, “going after the economic activity that we think would follow if Georgia gets selected [as a test site],” Weiss says.
The expectation, of course, is that such a site would attract supporting industries and create jobs – parts and aircraft makers and suppliers, maintenance and logistics people, technicians and researchers, adding to the more than 80,000 people (fifth in the nation) currently employed in all facets of Georgia’s aerospace industry.
In 1993, when she was still living in Los Angeles, Dianne Zimnavoda was contacted by the state of Georgia.
“They had formed a consortium of power companies, universities, state government agencies, and they were looking specifically to recruit aerospace companies. Somehow we made their short list,” says Zimnavoda, president of RCF Technologies, the company her engineer father founded in Los Angeles in 1975. They make specialty seals, hoses and couplings for aircraft out of an extremely heat resistant and proprietary material called Rishon.
“I met with a whole group of people, toured the larger aerospace places, and they basically raved about the state, how awesome it was to work here and so forth. Then I visited areas of the state I thought I’d be interested in,” Zimna-voda says.
“Our customer base is pretty much anyone you’ve ever heard of in aerospace. I ship around the world. But the parts we make are relatively small and extremely lightweight, so we use carriers like FedEx and UPS, which means we can be located anywhere – it makes no difference where I manufacture.”
So she moved her small, cutting-edge aerospace company from Los Angeles – “they’re not interested in business there,” Zimnavoda says – to the home of the world’s most famous onion.
“Vidalia made us a very good offer,” she says. “Gave us land, put up a building, and we’ve been here ever since.”
And she’s seen the aerospace industry skyrocket. In 2000, Georgia’s aerospace exports were $801 million. They’ve grown 618 percent since then. They grew 31 percent between 2010 and 2011 and 23 percent the year before that.
Job growth hasn’t been nearly as dramatic, but there has been some – 3,600 jobs in the past five years, to go with $982 million in projects from new or existing aerospace companies, according to GDEcD.
The biggest chunk of that is attributed to Gulfstream Aerospace Corporation, which manufactures business jets and announced in November 2010 that it would spend $500 million and create 1,000 jobs in a seven-year expansion project at its Savannah plant.
“I think we’ve done pretty well, been consistent. Our total aerospace employment has gone up while other states have been losing jobs,” Justice says.
The total job tally is up about 3.7 percent over the past five years, according to Justice, although the aerospace employment pulse has been uneven, with companies shrinking and expanding like balloons.
“It would be fair to say that aviation and aerospace was heavily impacted by the economic downturn,” says Haley Dunne, communications director for Bombardier (maker of the Learjet), the Canada-based aerospace company that opened a service center in Macon two years ago.
“We’ve had to reduce production on several product lines. There have been layoffs, but we’ve fared better than most. We invested in our company through the downturn, and we’re expanding again.”
Bombardier, the world’s only manufacturer that makes both trains and planes, employs about 70,000 people worldwide, about 5,000 of them devoted to servicing and maintaining aircraft for a variety of clients. They employ about 160 in Macon and expect to be adding more jobs after signing a nine-year heavy maintenance agreement with Republic Airlines.
One of Bombardier’s neighbors in Macon’s Middle Georgia Regional Airport is TIMCO Aviation Services, which has rebounded after “a rough patch in the road for a few years,” according to Keith Statzer, general manager of TIMCO’s Macon facility.
“The years 2008 and 2009 were hard for us. We got down to 100 employees, but we’ve added jobs. We’re coming back.”
Timco is one of the world’s largest independent aircraft maintenance, repair and overhaul (MRO) providers; its airframe facility has been in Macon since 1999. Over the past two years, they’ve added the Boeing 767 to their workload, modifying their 115,000-square-foot plant to accommodate the planes and adding personnel. They’re up to 300 employees at the Macon facility now.
Macon is in the middle of an area that boosters have dubbed Georgia’s “Aerospace Corridor,” a calling card that tries to prop up the aerospace activity and potential of the region near Robins Air Force Base, home of the Warner Robins Air Logistic Center (WR-ALC), where advocates are working to defend the mission of the massive military complex.
“Our goal in life is to make sure we are well positioned for the future, no matter what the national economic, political or social situation is,” says retired Major Gen. Rick Goddard, senior advisor to 21st Century Partnership, a coalition of regional political, business and civic leaders focused on Robins’ continued wellbeing.
Goddard is the former WR-ALC commander, and a former Republican Congressional candidate. His top priority is maintaining the base’s military mission: “If this country has to go to war, we need to have the critical mechanisms in place. That’s what these logistics centers are all about.”
Goddard, who piloted an F-100 fighter in 227 combat missions during the Vietnam War, is fighting for the future of the WR-ALC, one of three Air Force logistics centers in the U.S. (The others are in Oklahoma City and Ogden, Utah.)
“Each one is totally different, so we’re hoping the Air Force will realize they need these three logistics centers going forward,” says Goddard, thinking ahead to the next BRAC (Base Realignment and Closure) process.
President Obama has suggested another round of BRAC for 2013. Goddard figures it might actually be 2015 or 2017, so 21st Century Partner-ship is gathering itself to make a case for Robins’ continued existence.
Meanwhile, Goddard is worried more about being slowly nickeled and dimed into irrelevance: Pending and prolonged cuts in the nation’s defense budget (the Aerospace Industries Asso-ciation predicts a million jobs nationwide could be lost) and the recent realignment of Air Force Materiel Command, resulting in the loss of hundreds of civilian jobs at Robins.
“What we don’t want,” he says, “is death by a thousand cuts.”
A deep cut was made in Marietta, where the last F-22 Raptor rolled off the production line at Lockheed Martin in December, ending a 20-year, $65-billion program for the corporation, America’s largest military contractor.
The end of the F-22 did not result in immediate job losses, says plant general manager Shan Cooper.
“We’ve been fortunate so far. We’ve transitioned a lot of folks over to the F-35 program. I’d like to say that we’ll have no layoffs, but I can’t say that,” Cooper says. “We have placed some people in the P-3 and C-130 programs, and we’d like to keep everyone on board if possible.
“Meanwhile, we’re focusing on modernizing and sustaining the F-22. The aircraft that are already out there will need to be maintained, and we know the F-22 better than anyone else.”
Lockheed, which shares runway space with Dobbins Air Reserve Base and employs about 7,800 people in Marietta, sends green ripples across the state, spending about $325 million a year with 350 different suppliers in Georgia.
One of those is RCF Technologies, about 200 miles away in Vidalia.
“Lockheed just informed us that a very small part we make has been designated as the part for the C-130 aircraft, so our orders for that are up to 3,000 a month,” says Zimnavoda, who employs 32 people at RCF.
“For two solid years nothing was being done in the way of design anywhere in the industry, everything was on hold, people were closing down. We lost two thirds of our income.”
But now they’re making parts for Boeing’s 787, and two years ago they started branching into high-performance auto racing, Formula One and some NASCAR.
“Thank heavens,” Zimnavoda says, “we’re back in build mode.”
Congress gave the FAA until Sept. 30, 2015, to fully integrate UAVs into domestic airspace. But in April, the FAA released a list of more than 60 U.S. public and private entities that are already authorized to fly drones. It took some legal arm-twisting – the FAA was responding to a Freedom of Information lawsuit filed by Electronic Frontier Foundation.
The list included the usual suspects – Defense Advanced Research Projects Agency (DARPA), the different U.S. armed forces, NASA, local and federal law enforcement agencies, and about two dozen universities. The Georgia Tech Police Department’s Office of Emergency Preparedness and the Georgia Tech Research Institute were both on the list.
The robots are flying. Justice at the Aerospace Center of Innovation expects to be flying them this year, “to support our agriculture sector,” he says.
“We’re working jointly with universities and companies to test them. One of the things we’re looking to do is to gather imagery of farms, peanut fields,” he says. “Generally speaking, the idea is to ultimately help farmers increase their yields. It’s the intersection of aerospace technology and agriculture.”
Georgia is well equipped in aerospace research muscle – Tech’s Daniel Guggenheim School of Aerospace Engineering, for example, is considered one of the best in the nation. Then there is the work of Weiss and her colleagues at the GTRI who are developing the next generation of humanless flight.
Weiss says she works in the area of robotic autonomy, “making them fully autonomous, so they can make robust, reliable, proper decisions on their own, in unforeseen situations, as opposed to trying to script everything – if you see this, do that.
“And we’re looking at how they collaborate with other UAVs, or ground vehicles, and machines made by different manufacturers, with different software architecture – interoperability of disparate UAVs.”
The current trend is for humans to fly the drones from remote locations (the Air Force trains more pilots for UAVs than for any other weapons system). Human-controlled drones have been used by the CIA to hunt down suspected terrorists in Pakistan. Unfortunately, they’ve also been responsible for a number of civilian deaths.
After four decades of research in robotic flight, the drones are pretty capable of doing the work on their own – as Weiss and her colleagues have demonstrated, last year, for example, in the U.S. Army Robotics Rodeo at Fort Benning.
But if the thought of autonomous robots making life and death decisions gives you discomfort, you’re not alone.
“Researchers are doing a great job of making these machines smarter, capable of thinking for themselves,” Weiss says. “But robots making the decisions – that makes people nervous.”
Humans wouldn’t be rendered completely inessential, though. Not by a long shot. As robots and unmanned systems proliferate, maintenance and operations could become big growth areas, Weiss says, adding, “instead of human operators being ‘in the loop,’ or totally in command of the UAV, operators will be ‘on the loop.’
“So, the robot is making decisions autonomously, but the operator is there to hit the override. If this was cruise control, it would be like taking the wheel or hitting the pedal.”
In other words, you may not be driving, but you can always hit the kill switch. Just in case.
This article appears in the August 2012 issue of Georgia Trend