Frequently Asked Questions about Spring-Loaded Pogo Pins & Connectors

What are Spring Loaded Pogo Pins?

Mill-Max spring-loaded pins, also known as spring-loaded contacts or pogo pins, provide an alternative interconnect solution for transmitting electrical signals and power through their contact points. Mill-Max’s spring-loaded pins consist of a precision-machined plunger, body, and cap, along with an internal spring which provides a range of mechanical movement when assembled. Mill-Max offers many options for spring-loaded pins that incorporate different stroke lengths, diameters, overall heights and spring forces. Due to Mill-Max’s precision machining capabilities and extremely tight tolerances, a highly durable electrical connection can be achieved.

How are spring-loaded pogo pins constructed?

How do Spring-Loaded Pins work?

In a spring-loaded pin application, the plunger engages with a mating target contact and creates a surface pressure connection. As the spring is compressed and force is applied, the plunger moves inside the body. The primary path of travel is through the gold-plated outer components, and the electrical interconnect relies on the force of the internal spring to maintain contact between the plunger and the mating component. As the plunger is compressed further, spring force increases, helping maintain a reliable electrical connection with the mating surface.

What are the benefits of using spring-loaded pogo pins?

What are Spring-Loaded Pins used for?

Spring-loaded pins can be used in many electrical interconnect applications. Mill-Max offers spring-loaded pins in multiple configurations and stroke options which can be beneficial in applications with large stack-up tolerances. Spring-loaded pins are ideal for blind mating applications as the only connection required is for the plunger to engage with a mating target contact or contact pad. Whether the spring-loaded pin application is a simple board-to-board interconnect, or a more modular connection, Mill-Max has spring-loaded pins for your application.

What styles of spring-loaded pogo pins are available?

What should engineers consider when selecting a spring-loaded pogo pin?

What is the maximum stroke Mill-Max spring-loaded pins can provide?

Mill-Max offers standard spring-loaded pins with up to .118” (3 mm) of maximum stroke.

What is the recommended compression/travel range for Mill-Max spring-loaded pins?

Mill-Max recommends their spring-loaded pins operate at mid-stroke compression for optimal electrical and mechanical performance.

How many cycles are Mill-Max spring-loaded pins tested to?

Most Mill-Max spring-loaded pins are tested for 100,000 to 1,000,000 cycles at the recommended mid-stroke compression.

What is the highest current-rated spring-loaded pin Mill-Max can offer?

Mill-Max offers discrete spring-loaded pins with a maximum current rating of 13 A and a 20% derated current rating of 10.4 A. The derated rating provides a safety margin below the maximum current. For more information, see our Application Note, Application Note - Interpreting Current – Temperature Derating Curves

Are there alternative plunger styles for Mill-Max spring-loaded pins?

Most of Mill-Max’s spring-loaded pins have a plunger with a radius on the tip, however, we can also provide flat and pointed tip plungers as an alternative option for most spring-loaded pins.

Can I Swap the Spring in My Spring-Loaded Contact?

Yes, for certain spring families. Mill-Max offers compatible spring options within the following spring groups, allowing you to change spring force without changing the overall contact design:

• 50 ↔ 80 Series Springs
• 72 ↔ 75 ↔ 87 Series Springs
• 62 ↔ 82 Series Springs
• 63 ↔ 83 Series Springs

These spring families share compatible dimensions, making it possible to substitute one spring for another to achieve a different operating force.

Before selecting a replacement spring, review the Internal Spring Selection & Performance Guide to compare force curves, travel characteristics, and performance specifications.

Not all springs in each group are interchangeable. Contact an applications engineer to determine interchangeability.

How are spring-loaded pogo pins mounted?

What are mating targets for spring-loaded pogo pins?

Can Mill-Max spring-loaded pins mate with a dedicated pad on the opposing surface?

Mill-Max spring-loaded pins can mate with any conductive surface. For optimal electrical and mechanical performance, we recommend mating against our dedicated target contacts and target discs.

Are Mill-Max spring-loaded pins sealed or waterproof?

Mill-Max spring-loaded pins are not IP-rated but they have been used in waterproof/IP-rated applications. A typical Mill-Max spring-loaded pin consists of four key components: a precision-machined plunger, body and cap, along with an internal spring. When a spring-loaded pin is compressed, the plunger will move inward, residing inside the pin’s connector body. This movement will create an entry point for liquids or contaminants. For waterproof applications, Mill-Max spring-loaded pins can be installed into their own sealed housing that utilizes gaskets or O-rings to create a sealed environment for the pins to function. For more information, contact us.

Can Mill-Max spring-loaded pins be subjected to washdown procedures?

While we do not provide any formal guidelines regarding washing down of our parts, we are aware of customers who have successfully performed this type of operation by using mild cleaning solutions, such as soap and deionized water. If your application requires the use of more aggressive cleaning solutions or procedures, we suggest testing the proposed cleaning process to ensure that it does not damage the spring-loaded pin or the gold plating finish. Avoid using solutions that leave a residue that may hinder the movement of the plunger and/or internal spring.

Are Mill-Max spring-loaded pins or connectors lubricated?

Mill-Max spring-loaded connectors are not lubricated. Customers have successfully used light-viscosity oils in some applications. Typical applications do not require lubrication.

Are Mill-Max spring-loaded pins and connectors available on tape and reel?

Most discrete spring-loaded pins can be packaged on tape and reel. Some factors that determine whether a part is suitable for tape-and-reel packaging include overall length, largest diameter and retention features.

Some Mill-Max spring-loaded connectors are available on tape and reel with a pick-and-place clip.

Do spring-loaded pins on tape and reel require a pick-and-place cap?

Most spring-loaded pins are suitable for automatic pick-and-place assembly when a suitable pick-and-place nozzle is used. Mill-Max also offers several series with a removable pick-and-place cap to aid with automated assembly.

Are 3D models of Mill-Max spring-loaded products available?

STEP models for most Mill-Max products are available for download directly from the applicable product page. Select “I Want To,” followed by “Download 3D Model.”

Can Mill-Max spring-loaded pins be customized?

It is possible to modify existing Mill-Max spring-loaded pin designs or create completely new designs upon review for manufacturing feasibility. Most Mill-Max spring-loaded pins consist of four key components: a precision-machined plunger, body and cap, along with an internal spring. Custom discrete spring-loaded pins have a minimum order quantity of 1,000 pieces. An NRE charge may apply when a new spring or new machined component is required. For more information, view our Custom Capabilities.