King Pin | Bead Electronics Blog

Choosing the Right Base Metal for Custom Connector Pins

Posted by bead electronics on Dec 15, 2021 11:00:00 AM


Though millions of connector products are on the market, it’s not always possible to find the exact solution for a project. Enter custom connector pins. Nowadays, we can customize our connectors to every size, configuration, and capability we need. Custom designs have many benefits over standard connectors.

They allow designers to remove any unneeded features, expenses, and complexity. What’s more, they can be made to fit the same usage profile that a design specifies. But how do we know we're making the best choice for our overall product?

To answer that, in this article, we’ll be looking at how different base metals influence the strength, durability, and useability of custom pins. We’ll be outlining the best options for pins, so you can make the best decision for whatever base material you choose.

bead-blog-base metals

Properties

There are slight differences between metal contacts that can make a big difference to the finished product's performance. Therefore, we’ll be taking a look at the following properties for each metal:

Tensile Strength

In short, tensile strength tells us the resistance of the material under tension. This is relevant for the metals' mechanical performance and gives us some inclinations as to the potential durability of the overall product and best use cases.

High tensile strength means that after each time a connector connects and disconnects correctly, the contact will spring back into place accordingly. As such, future connections will be successful.

Conductivity

We'll use the Material IACS (International Annealed Copper Standard) to compare conductivity, ranging from 100% conductivity to 0%.

In connectors, we need the current to pass across potentially many different interfaces without damaging the signal. Often we have to balance out electrical capacity with other factors such as strength and machinability.

Also, under the remit of conductivity, it is worth considering which electrical contact type and size you will need.

Signal

This is used to communicate information from a source to a destination over an electrical signal.

This type of contact doesn’t usually transfer as much current and voltage. This means a smaller contact can be used.

Power

On the other hand, electrical power contacts may require high current and voltage capacity. As such, a larger contact area is needed.

The larger the conductive portion of a connector, the thicker the walls. Though thicker contacts will be more durable, they are usually lower in quality and low in cost.

Machinability

This refers to the effort or exertion on our tools required to machine a specific material. By machine, we mean the ability to cut through the metal at a satisfactory finish while also accounting for cost. For instance, a harder material will take more power, time, and cost to cut through because of the wear exerted on the cutting tools to reach a finished product.

A machinability rating is measured against the weighted averages of the standard cutting speed, surface finish, and tool life. For example, a rating of 100 is easiest to machine and 0 is the most difficult.

Cost

The cost will be more significant for better current carrying capacity and tensile strength.

However, understanding the properties necessary for a specific project may be undercut by sacrificing certain elements that won’t impact the final outcome.

Availability

There are two elements to availability to consider.

First is the scarcity of materials that will be more difficult to source and will be more expensive. Secondly, the time it takes for the product to be delivered will impact the overall project timeframe.

bead-base metals-brass copper

Base Metals

With these properties in mind, let’s compare some of the most common base metals: brass, beryllium copper, and phosphor bronze.

For more information on best practices for plating your custom connector pins, download our free eBook.

Bead-Blog-BrassBrass

Brass is a copper and Zinc alloy, though it usually contains small amounts of other alloying elements. As a result, it has high corrosion resistance and ductility.

For this reason, when the connectors connect and disconnect, the socket beams will return to their original position, and the terminal beam will not be able to properly connect with the socket. Brass is, therefore, best used for permanently set sockets that are not required to bend or move.

Tensile Strength of Brass

Brass has an excellent tensile strength of 360 MPa, but a low yield strength of only 140 MPa.

Conductivity of Brass

Brass has decent conductive properties. Material IACS conductivity is 28% better than phosphorus bronze but not as good as beryllium copper.

Machinability of Brass

The machinability rating is 40/100 (for an alloy with a copper content no less than 60%). This means brass is easier and less costly to machine than the other metals on our list.

Availability of Brass

Brass is widely available, though alloys with specific copper compositions will be more challenging to find.

Cost of Brass

Brass is the least expensive of the three metals.

Common Uses of Brass as a Base Metal

  • High strength components
  • Commercial applications
  • Circuit boards
  • Valves
  • Valve stems
  • Fittings
  • Weld tabs

Now, let's take a look at beryllium copper...

Bead-Blog-Beryllium copperBeryllium Copper

Beryllium copper is a composition with over 90% copper and a lower Beryllium and carbon monoxide content. Beryllium copper is particularly ductile, which means once hardened, it will hold its shape under harsh conditions.

Due to the strength and durability of Beryllium copper, it is suitable for miniature connectors.

Tensile Strength of Beryllium Copper

Beryllium copper has a high tensile strength of 1280 - 1480 MPa and a yield strength of 965-1205mpa.

Conductivity of Beryllium Copper

Beryllium copper has excellent conductive properties, primarily because it is a copper alloy. Material IACS conductivity is between 45–63% which is far better than the other two metals.

Machinability of Beryllium Copper

The machinability rating for beryllium copper is relatively low at 20/100. This means Beryllium copper is harder and more costly to machine than the other metals on our list.

Additionally, extra heat is required for the alloy to reach its full tensile strength.

Availability of Beryllium Copper

Beryllium coppers can be difficult to source.

Cost of Beryllium Copper

Beryllium coppers tend to be the most expensive of the three metals. This may relate to the fact it is more difficult to find and machine.

Common Uses of Beryllium Copper as a Base Metal 

  • High-cycle applications
  • Micro connectors
  • Harsh connector conditions
  • Telecommunications products
  • Computer components
  • Small springs

Finally, let's turn our attention to phosphor bronze...

Bead-Blog-Phosphor bronzePhosphor Bronze

Phosphor bronze is a copper, bronze, and phosphorous alloy. It has a good combination of ductility and strength, which means good spring qualities.

When the connectors connect and disconnect, the socket beams will return to their original position, and so will the terminal beam.

Tensile Strength of Phosphor Bronze

Phosphor Bronze has a mid-range tensile strength of 324-965 MPa and a yield strength of 131-552 MPA. This makes it suitable for smaller connectors but not as strong as Beryllium copper.

The tensile strength of Phosphor Bronze is still not good enough for socket contacts smaller than 20 gauge.

Conductivity of Phosphor Bronze

Phosphor Bronze has the lowest conductivity of the metals. Material IACS conductivity is just 15%. Machinability The machinability rating is the same as Beryllium copper at 20/100. But phosphor bronze doesn't require extra heat to reach its full tensile strength.

Availability of Phosphor Bronze

Phosphor Bronze is generally easy enough to source.

Cost of Phosphor Bronze

Phosphor Bronze costs more than brass but less Beryllium copper.

Common Uses of Phosphor Bronze as a Base Metal

  • Pitch connectors
  • Bigger contact systems with longer beams with more deflection
  • Shafts, fasteners
  • Valve spindles
  • Springs and gears

...to name a few!

Are You Ready to Use the Right Base Metal for Custom Connector Pins?

With this information, we hope you’ll be able to make the best choice for your connector pins. Still, suppose you need custom connector pins. In that case, you can get professional, affordable, and custom-manufactured pins directly from us. We can get your project on the road with delivery in as little as two weeks. So take a look at our services, and contact us today if you have any questions!

Topics: Custom Contact Pins, Custom Connectors, Bead Electronics, Bead Industries