Selecting the Right Contact Base Materials for Use in Electrical Engineering Applications

When designing a device or switch that calls for electrical contacts, it’s important to know what metal characteristics and properties you need for optimum performance. Choosing the right base materials will ensure that the contacts in your product will last the life of your product. A good electrical contact manufacturer will work closely with you to determine your exact needs and recommend the perfect electrical contact for you. They can also let you know if there are any concerns for your specific application.

Electrical contacts are an important part of any electrical device. They’re especially important for switching devices as they must remain in good physical and electrical shape for the life of the product. If they wear out too quickly, the product’s useful life will be shortened. Contact materials must exhibit a number of properties to work well and withstand the process of completing and breaking the electrical circuit. Some of those properties include high arc erosion resistance, high resistance against welding, and good arc extinguishing capability. Let’s look at a few excellent choices for electrical contact materials.

Alloys

An alloy is a combination of two or more metals that is better than each individual metal on its own. Electrical contact manufacturers can mix metals in such a way to take advantage of the properties for both, while minimizing the negative properties of each individual metal. The result is an alloy that can be customized for your specific needs, ensuring that it will last for as long as necessary.

Composite materials

Composite materials are similar to alloys but typically use materials other than metals as part of the blend. Composites are particularly valuable for situations that utilize higher electrical current. Composites can be made to better resist and withstand the tendency of high electric current to arc and weld contact surfaces together. Composites are typically made through a sintering process to ensure that the materials are evenly distributed throughout the contacts.

 

Different Materials Used in Manufacturing Electrical Contact Assemblies

The selection of contact materials for your electrical contact assemblies is an incredibly important part of the planning process. It’s always advised that you discuss the application requirements with an engineer or other professional as early in the design process as possible. Of course, depending upon your specific needs, there could be multiple options available in terms of the materials to be used. Each contact material will obviously come with its own pros and cons, whether that’s a tendency toward welding or “sticking,” or simply affordability. There’s also the concern of whether or not you’ll require UL or IEC approval. To learn a bit more about the different materials used in manufacturing electrical contact assemblies, you can continue reading below.

Silver Tungsten

Also known as AgW, silver tungsten is a popular material for use in both large air and oil circuit breakers. It’s known for having a high resistance to arc erosion. It’s also a common choice for re-closures, line disconnects, and both high current contactors and switches. Thanks to its resistance to welding, it can also serve as a good shorting contact. Composites of silver tungsten that contain more silver are used quite often in circuit breakers and in high current contactors.

Copper Tungsten

Commonly known as CuW, copper tungsten is also a very popular contact material. It’s known for being heat-resistant, ablation-resistant, easy to machine, and it’s both highly thermally conductive and electrically conductive. Copper tungsten can serve as an excellent material for switches and contacts for oil-filled devices. Thus, copper tungsten is a material commonly found used in the fossil fuel industry, as well as related industrial and commercial fields. You may also find it used in some oil, gas, or even air circuit breakers.

Silver Graphite

Sometimes shown as AgC, silver graphite is popular for many electrically conductive applications. It’s also known for having the best anti-welding properties of all contact materials. Because it has the best protection against contact welding, it’s an excellent choice for closed contacts under short circuit conditions. It’s also known for having low contact resistance and low erosion. For industrial purposes, silver graphite is excellent for circuit breakers, but it’s also effective for residential circuit breakers.

This is by no means an exhaustive list. Putting together the best electrical contact assemblies always necessities identifying the appropriate materials, so it’s always recommended that you discuss your application requirements at length before making a final decision.

Contact Rivets – A Checon Perspective

Rivets used as electrical contacts are often used in low to mid-power switching applications. Checon recognizes that certain devices are best suited for a contact rivet design and we support rivet production by supplying wire to our rivet manufacturing affiliate in India as well as maintain manual and automated rivet insertion capabilities to produce assemblies in both the U.S. & India. We also recognize that there are often opportunities to move to low cost, high-reliability alternatives such as in-press wire welding or tape welding. Checon has assisted numerous customers in their design and cost out processes to help them better understand these options and appropriate application. To learn more about how electrical contact rivets are manufactured and utilized along with a more detailed explanation of the alternative cost-out opportunities, please continue reading.

Rivet Production & Assembly

Since contact rivets are formed by cold forming and brittle material can cause cracking during this process, Checon recognizes and meets the standards that the manufacturing of a solid or bi-metal contact rivet requires with consistently ductile contact material. The cold forming process can produce several different contact shapes, the most common being round with a spherical radius. Solid silver contact rivets can be produced in a variety of materials including fine silver, AgNi, AgCdO, & AgSnO. Composite bi-metal rivets are often used to save on precious metal content and expense depending upon the material system and application needs. Copper is commonly used as the base shank material. Rivet insertion to produce contact assemblies at Checon can be accomplished manually or by an automated process. Staking is carefully monitored and repeatable to ensure proper seating of the rivet with the required twist-out torque requirements.

Alternatives to RivetsChecon’s In-Press Wire & Tape Welding operation offers a low-cost option when compared with many riveted designs. High speed, one operation, in-press welding is a core competency at

Checon’s In-Press Wire & Tape Welding operation offers a low-cost option when compared with many riveted designs. High speed, one operation, in-press welding is a core competency at Checon allowing us to develop the most consistent, high quality welded contact assemblies in the industry.  By connecting our weld head design to a large bed, high-speed vertical press via an innovative actuator design, we can dramatically increase production speeds to up to 400 assemblies per minute. Both electronic & mechanical shear testing is conducted on each contact before each welded contact moves into a Checon designed Class A progressive stamping die for coining of contact shape and stamping into a final contact assembly.

For more information on how Checon can help you maximize your contact and contact assembly performance while minimizing your costs, call Paul Thomsen directly at (508) 809-5159-office, (508) 801-2417-mobile, or, email him at thomsen@checon.com.  Checon also offers an on-line live chat via our website at www.checon.com.

Benefits of Welded Electrical Contact Tapes

Although you may not realize it, electrical contact tapes are present in many kinds of electrical equipment. Electrical contacts are used in circuit breakers, switches, timers, and many kinds of wires. From to your kitchen to your entertainment system, electrical contact materials are making things tick all over your home, but you might not know how they work. Keep reading to find out.

Contact tapes are overlaid and welded onto electrical equipment to ensure the effectiveness of electrical flow. These tapes contain a cap of precious material, which is needed for the electrical device to function. Also, they have a base of non-precious metal which works to support the cap and facilitate attachment. By precisely controlling the thickness of the tape, the conductivity of the equipment can be maximized, while providing protection during the welding process. Electrical contacts provide many benefits during the welding process, and there are several companies that produce these materials.

Manufacturers

Producers of electrical contact tapes sell to both individuals, as well as businesses that require this tape for their operations. Many electrical contact manufacturers also specialize in producing metal and plastic parts that can be used in electrical manufacturing. On the other hand, a company like the Checon Corporation specializes exclusively in electrical contact materials, working to create the most high-performing materials possible.

Checon offers a wide variety of contact materials. They also offer to fabricate and customize contact materials, depending on your specific needs. This guarantees the contacts you order will be the most effective for your specific application. Finally, Checon uses in-house development programs and electrical tests, which allows them to offer the highest performing contacts possible.

Benefits

Welded electrical contact tapes provide several key benefits in the operation of electronic equipment. Contact materials make sure that electricity flows correctly and does not cause short-circuits or overloads. Finally, these materials also maximize electrical equipment’s conductivity, thereby ensuring that they operate correctly. If you or your business needs electrical contact materials, consider visiting checon.com to view their wide selection of materials.

Different Metals Used in Making Electrical Contacts

There are several materials and alloys that are used in creating contact materials in electrical contacts, which are both meant to help construct electrically conductive connective materials. Here are some different alloy materials used in constructing electrical contacts.

Refractory Contacts

Refractory contacts are important in helping conduct electrical current through strategic placement in devices. The necessary conductivity and resistance help determine just what materials should be chosen for your product. The following are materials used to create refractory electrical contacts:

  • Silver tungsten
  • Silver Tungsten Carbide
  • Silver Graphite
  • Silver Tungsten Graphite Carbide
  • Copper Tungsten
Buttons

In successful electrical contacts manufacturing, buttons help your finished product be as effective as possible. The following are alloys used in the composition of creating both single buttons and multi-layer buttons:

  • Silver Cadmium Oxide
  • Silver Tin Oxide
  • Silver Nickel
  • Silver Alloy
  • Copper and Copper Alloy
  • Steel and Nickel Monel
  • Braze Alloy
Rivets

Rivets are created with the distinct purpose of extending that conductivity. The materials used and how they are constructed need to target the specific construction needs of the end-result product. The following are types of rivets that are manufactured to serve electrical contacts:

  • Construction
    • Solid
    • Multi-Layer
    • Head and Shank
      • Straight Side
      • Chamfer Side
      • Step Side
      • Indent
      • Chamfer
      • Riveted Assemblies
Surface Features and Shapes

Varied shapes serve distinct purposes for the benefit of your products. The following alloy distinctions can help make a more intuitive design that enables a more efficiency and resiliency. Here are some characteristics that can be expected:

  • Knurl and Score Lines
    • For Backing Designations
    • Projections
      • For Welding
      • Nibs
        • For Locating on the Substrate
        • Serrations
          • For Desired Performance
          • Shapes
              • Square
              • Rectangular
              • Circular
              • Washer
              • Cylindrical
              • Spherical

            There are a wide range of metals that are used in making electrical contacts. In order to create a manufacturing plan best suited to your product, it doesn’t hurt to consult with an electrical contacts manufacturer to learn more.

Understanding the Principles and Applications of Electrical Contact Assemblies

Electrical contact assemblies are important in creating a wide range of products and components used in electrical devices. Let’s take a look at what exactly they are, and how they work.

The Basics of Electrical Contacts

An electrical contact is a component found in an electrical circuit that helps to complete it and allow for electrical current to successfully flow from one point to another. These electrical contact components occur in switches, connectors, circuit breakers, and relays, and they can be formed out of a range of materials depending on how well those materials both successfully conduct electricity and resist corrosion over time. The materials used in electrical contacts are also often chosen related to how affordable they are and how cost effective they are over time.

Electrical Contact Assemblies

Creating these small parts and components is just one phase of the process. Some companies also offer to help assemble these parts into a specific device, taking a set design, interpreting it, and putting into action the needs of a design plan according to what electrical contacts are needed and where. These assembly services can also involve a company partnering with an assembly group in order to have them manufacture electrical contacts that meet certain custom specifications.

Types of Electrical Contacts

These conductive parts can get pretty specialized. Buttons, rivets, various conductive surface features, and an array of refractory contacts are used to make up electrical contacts. They can be made from silver tin oxide, copper tungsten, silver graphite, and a wide range of other alloys that can accommodate different needs.

Electrical contact assemblies are incredibly important in the design and manufacturing of a wide range of electronics. These tiny conductive parts make the most everyday tools we use possible, from a television remote to a light switch to our cell phones. The next time you flip that switch or turn that knob, think about the tiny parts that are all working together to connect that circuit and make it work for you.

Different Types and Traits of Silver Tin Oxide

Silver does more than shape the way for wedding bands and fine jewelry. Different types of silver tin oxide have several specific traits that enable them for use in a variety of settings.

Pure Silver

This is also sometimes referred to as fine silver. Of all types of silver, pure silver is the most conductive—meaning it conveys electrical current the easiest. It also resists oxidation better than other silvers. On the flip side, it gets softer at lower temperatures than other silvers and, therefore, doesn’t stand up as well to mechanical wear. It also attracts sulfur, which means that sulfur can easily tarnish the exterior look of pure silver over time.

Silver Alloys

In order to take advantage of the strengths of pure silver, while minimizing the negative properties, silver alloys are created by combining a variety of other metals with pure silver in varying degrees. The goal in doing so is to strengthen the hardness of the silver and make it more resistant to wear. In some cases, it’s also to diminish its ability to conduct electricity so well.

Fine-Grain Silver

Nickel is the added ingredient that makes for fine-grain silver. As a result of the properties of liquid silver and nickel, only a small amount of nickel can be merged to form fine-grain silver. This material maintains its resistance to chemical corrosion while upping its hardness and overall strength as a metal. The nickel also slightly diminishes the conductivity.

Hard-Silver Alloys

Copper is the extra ingredient added in hard-silver alloys that greatly increases their mechanical stability. This is also referred to as hard-silver in Europe, and its mechanical stability and greater resistance to erosion make it a highly reliable material.

Silver tin oxide is just one of several different forms that silver can be used in. The varied uses of silver and its different variants make it highly useful in a wide range of industries.

Your Forecast Is More Than Hot Air!

Many of Checon’s major customers provide us with forecasts of one sort or another. Most are loosely based on their customers’ expected orders as well as on any additional estimates their customers may provide to them. As you can imagine, this continues on to our customers’ customer, that customer’s customer, and so on. So it comes as no surprise that any changes in demand from the end user of our products will often result in significant fluctuations in the forecasts throughout the supply chain.

For many suppliers this can lead to frustration. If you schedule production based on a forecast and the forecast then changes you may end up with excess inventory of one product and shortages of another. I’ve heard other manufactures express this frustration with statements like “their forecast is worthless”, or “full of hot air”, or “I don’t even bother to look at it”. That’s because they are using it for the wrong purpose. Don’t build based on forecast, plan with it!

Checon understands that we need a flexible manufacturing system that can respond to changes in demand both small and large. How large? Well that depends on our customer’s ability to ramp up its production. For those that can react, we have tailored our system to respond to large fluctuations. Working closely with our suppliers, we have integrated their response capabilities into a manufacturing system built on a foundation of short setup times, small production runs, strategic inventory points, and a fully automated Kanban pull system. How we load that system is based on our customer’s demand profile. The result is fast and flexible delivery that has been over 96% on-time for more than five years!

So what does this have to do with forecasts? Absolutely nothing! Checon’s agility allows us to manufacture based on our customer’s demand, not on their forecast. But their forecast can provide information about their current outlook. Will they take what they forecast? Probably not, but we can still glean valuable information from what they think they will take, and plan accordingly. So please, keep giving us your best guess at what you will need, and we’ll take it from there.

Electrical Contact Manufacturing- A Checon Success Story In the Midst of the Technology Revolution

Have you ever met someone with a newfangled digital camera who thinks his photos are on par with a professional photographer’s? Or what about the guy who is suddenly an architect now that he can create a layout of his house using the free software program he picked up at the big orange home center?

Technology is transforming our everyday life faster than many of us can absorb and adapt. And while it is true that such gains often allow us to perform tasks and activities previously unattainable with outcomes that make us feel like “experts”, it is also often the case that there is no equivalent for the added value that only years of experience can bring to quality and performance.

Having been in the electrical contact manufacturing business for over 55 years, Checon has seen numerous technological and market changes. We have seen both domestic and international competition come and sometimes go. We have seen sourcing trends to low labor markets with the vision of quickly and easily transferring electrical contact manufacturing to fully automated approaches actualize with very limited success. We have seen competition exit either in part or whole from the marketplace because of an unwillingness to invest in the infrastructure required to maintain OSHA compliance and protect their employees when dealing with certain electrical contact materials.

Through it all, Checon has withstood and endured the test of time by consistently growing and adding to our core technologies. Yes, embracing new technologies has positioned us at the forefront of our field. But it is our foundation- drawing on years of producing proven performance, high quality, and price competitive product offerings to the electrical device industry- that distinguishes us from our fledgling competitors.

Checon’s development of several robust and tested electrical contact materials and contact assembly processes is what defines us as a company and has set the standard for decades in electrical contact manufacturing. We could not have done it without technological advances in manufacturing, quality and electrical testing, logistics, material sourcing and communications. What sets us apart from offshoring interests is our proven experience, which when combined with the right technology, builds the best possible electrical contact for our customers’ devices.

Have you ever met a company that is an expert in what they do?

I invite you to call Checon today to learn more!

Wire Welded Electrical Contacts vs Rivets

Checon has recently seen an uptick in interest from some of our biggest customers to change their electrical contact specification on select devices from rivets to a wire welded contact design.  Their reasons range from functionality, repeatability, quality and economics.  This last factor is the chief motivator with purchasing and engineering teams increasingly tasked to drive further cost reductions. Many are finding that wire welded electrical contacts vs rivets can deliver a viable ROI over in-house riveting operations and, in some cases, over purchased rivets where the need for improved quality is at play.

Wire welded electrical contacts vs rivets – why are so many of our customers thinking about switching?

Engineering

There has always been a strong argument to switch from the engineering side. After all, the attachment is a direct weld versus a mechanical press fit, allowing for better conductivity of both electrical energy and heat. By shear testing 100% of parts produced, the integrity of the weld is assured.

Supply Chain Management

When a high-speed wire weld process is used, buyers reduce three SKU’s to one. This cuts the number of purchased components in half and eliminates the assembly altogether. As companies experience change and turnover in their purchasing groups, they seek to streamline the purchase process and reduce the total number of suppliers they must manage.  The decision to purchase wire welded electrical contacts vs rivets produced in house, eliminates the downtime waiting for components to arrive as well as the cost of shipping, securing and inventorying raw materials including costly precious metals.

Process and Material Cost Reductions

Wire welding uses the same wire as a rivet heading machine, but integrates the attachment and coining of the contact tip right into the stamping of the brass or copper part. This eliminates both the cost of making a rivet and staking it to the part. In many cases, two parts can be made with every stroke of the press to produce more than 600 assemblies per minute!

With the cost of labor, personnel turnover, and employee training to assemble two units together significantly reduced with a wire welded design, the challenges of machine downtime as a result of misfeeds and repair are also eliminated.    The one step process of wire welding eliminates these issues and produces 100% usable parts.

RoHS

To meet RoHS compliance, many of our customers are working to replace the cadmium specified in a AgCdO rivet with an AgNi wire welded contact.

Checon’s Answer

With 100% usable parts, fewer suppliers, lower shipping costs, less machinery to maintain, lower labor costs, and overall savings due to fewer process steps, no wonder so many of our customers are considering switching from rivets to wire welded electrical contacts.

To find out more about our wire welded solution, call Steve Carter at 508-809-5112, or email him at carter@checon.com.