What are Spring-Loaded Connectors

Selecting the right spring-loaded connectors saves not only expenses in the long-term, but reputations as well. In most key applications, reliably machined pin contacts can significantly reduce the total cost of ownership.

Industrial applications are cost-sensitive. Hence, designers tend to specify solutions that cost the lowest. However, while ensuring the price of their solution is competitive, designers must also ensure their company remains profitable. This is because a low-cost, low-quality connector solution can easily lead to premature failure and considerable re-work costs, while possibly damaging reputations.

This is where machined pin spring-loaded connectors come in. There are numerous ways in which these precision-made interconnects can provide better solutions while improving efficiency, and lowering overall costs.

In a spring-loaded connector, the main components are the spring-loaded pins—also known as pogo pins, spring probes, or spring pins. They provide highly reliable interconnecting solutions for a wide variety of demanding applications. In typical spring-loaded connectors, manufacturers provide precision-machined contacts to ensure low resistance, high quality, and compliance.

Spring-loaded contacts typically comprise three or more separate machined components, assembled with an internal spring. Manufacturers precision-machine these components from brass and electroplate them with gold for ensuring excellent electrical conductivity, corrosion resistance, and durability. They assemble these contacts into high-temperature insulators to produce spring-loaded connectors in various configurations. In the market, these connectors are available in SMT, through-hole, and wire termination styles. They are also available in horizontal or vertical orientations.

At working travel, contact resistance is typically less than 20 milliohms, while the current capacity can range from 2-9 A continuous. Most manufacturers offer connectors they rate for 100,000 to 1 million cycles, with an operating temperature range covering -55 °C to +125 °C—depending on application variables like exposure time.

Precision machining is the most reliable and flexible method of making pins for connectors. The process delivers not only high quality but is also repeatable while offering material flexibility and versatile design. The process creates high-precision pins with cylindrical geometry, which are also known as turned pins. Precision machining is highly accurate and remarkably consistent. It can hold critical feature tolerances to +/- 0.0005”(0.0127 mm) or better.

Designers often have an incorrect perception that machined spring-loaded pins are high-cost solutions, beyond their budgets. The basis of their perception is the high-quality processes and materials manufacturers employ in the connectors. While there is justification for higher piece-part costs, the overall price of the connector is lower because of the several benefits and features the spring-loaded pins provide.

For instance, a spring-loaded pin may be simply contacting a pad on a mating PCB. The diameter of the mating pad provides the amount of positional tolerance that the spring-loaded pin can tolerate. Consequently, the spring-loaded pin solution offers tolerances in the x, y, and z directions. This ensures not only better overall functionality, but also reduces assembly time. Moreover, the Bill of Materials has only one part number instead of two.

Many designs today feature a packed occurrence with a lack of visibility in the connection area, typically known as blind mating. Here again, positional tolerances offer an advantage to the spring-loaded pins and connectors.