CNC Manufacturing Press Fit Connector High Current Reliable Press Fit PCB Connector

Description

What Are Press Fit Connectors?

Press fit connectors are electrical connectors that form a strong, solder-free connection by being pressed into plated through-holes (PTH) on a PCB. Instead of using solder, they rely on the elastic force of slightly oversized pins that compress when inserted, creating a tight, gas-sealed and corrosion-resistant joint—often called a “cold weld.” This technology offers high reliability, especially in harsh environments with vibration, temperature changes, or other stress.

Materials of Press Fit Connectors

The materials used for press fit connectors are chosen for their mechanical properties, conductivity, and durability:

• Copper Alloys: These are most common for the connector pin itself due to their excellent electrical conductivity and spring-like properties necessary for the compliant pin action. Examples include brass, phosphor bronze, and beryllium copper.

• Plating Base Materials: Underneath the surface finish, a nickel underplating is often used as a barrier layer to prevent diffusion between the copper pin and the final finish, and to enhance durability.

Surface Treatments of Press Fit Connectors

• Tin-Lead (Sn/Pb): A traditional finish with good performance, but its use is limited due to environmental regulations.
• Pure Tin (Sn): A common lead-free option, but carries a risk of “tin whiskers” that can cause short circuits.
• Silver-Tin (AgSn) Alloy: An advanced lead-free finish that resists whisker growth and allows for easy insertion.
• Indium (In): A soft, lubricating lead-free finish that enables low insertion force and high retention, with minimal whisker growth.

Specifications of Press Fit Connectors

Press fit connectors are characterized by several key specifications:

• Pin Design: Primarily use compliant pins (e.g., “fish-eye”) that flex for a secure, low-damage fit. Rigid pins are rare as they risk harming the PCB.
• Pin Count & Pitch: Range from single pins to high-density multi-pin connectors with various spacing options.
• Hole Size: Designed for specific plated through-hole diameters and PCB thicknesses to guarantee a proper, secure fit.
• Standards: Typically comply with industry standards (e.g., DIN EN 60352-5) governing press-fit connections.

Application of Press Fit Connectors

• Automotive Electronics: Used in critical systems like engine control, braking, airbags, and electric vehicle batteries for its vibration and temperature resistance.
• Aerospace and Defense: Essential for avionics and communication systems where extreme reliability in harsh environments is mandatory.
• Industrial Equipment: Applied in robotics, heavy machinery, and automation controls for its durability against shock, vibration, and long-term use.
• Telecommunications and Data Computing: Utilized in servers and network infrastructure where high reliability and signal integrity are paramount.

An Excellent Case: Automotive Transmission Control Module

In modern automotive transmission systems, a press fit connector is employed to link the transmission control unit (TCU) to sensors and actuators. The connector must withstand constant vibration, temperature fluctuations (-40°C to +125°C), and exposure to fluids. Using a gold-plated beryllium copper press fit connector ensures:

1. Zero Solder Defects: Eliminates thermal joint failures caused by reflow soldering.

2. Vibration Resistance: The compliant pin design maintains electrical continuity under extreme shaking.

3. Long-Term Reliability: The gas-tight interface prevents oxidation and corrosion over the vehicle’s lifespan.

4. Assembly Efficiency: Automated pressing tools enable high-speed installation, reducing manufacturing costs.