PCB termination: Quick contact, versatile connection

The machine and plant construction sector is seeing significant growth in the deployment of power electronics and high-current processing on printed circuit boards (PCBs). The Han-Fast Lock can help manufacturers reliably and flexibly supply boards with high currents by supporting surface-mount device (SMD) packaging and allowing fast connections for a wide range of connectors.

Transferring high currents on PCBs involves a special challenge. Due to different contact resistances, each connection has a special impact on the circuit board layout. Different contact designs result in different solutions for the PCB’s optimal heat management.

In general, the longer the conductor lines, the poorer the thermal conductivity, and consequently the greater the risk that hot spots form on the PCB. This risk also arises when several high-current contacts are positioned too close to one another. For this reason, PCB designers try to keep conductor lines for the power supply short, while placing the contacts as close as possible to elements such as transformers, transmitters, and power transistors (e.g., insulated gate bipolar transistors).

The difficulty is minimizing the amount of space taken up on the board for the connection point, while leaving enough room to allow plug-in connections. In the past, the solution was to place an additional component on the PCB and to solder the contact on or attach it via a press-in connection.
 

Just a few steps

The Han-Fast Lock makes it possible to solve these challenges on the PCB with a single component in just a few steps. The device provides the PCB with a standard through hole and a support pad. The hole’s inner surface serves as the contact area. A crimping tool can be used to provide the individual contacts and cables with uniform and force-fit connections outside the circuit board.

The Harting type BC-SC automatic crimping device allows fast processing of Han-Fast Lock contacts on a reel. Designed as a stripper-crimper, it automatically strips the conductor and crimps the contact after the sensor has been triggered. The automatic crimper works quickly and ensures that the crimping is reproducible and gas-tight.

Pick and place machines can attach the crimp contact in a 4.4mm standard hole on the PCB without solder by pressing a locking pin down. Contacts without pins, however, can also be positioned with the help of a plastic adapter. The Han-Fast Lock can place currents up to 60A – with a 10.0mm2 stranded wire – onto the PCB.

The plug-in termination technology meets the most stringent demands made on connectors for PCBs:

• Connection points freely positioned
• One contact hole with a standard size and design required for the connection
• No additional processing steps
• Contact can be unlocked and re-locked

Industrial connectors with modules or contact inserts for the various currents are available to connect the boards. Compared to Han DD contact inserts with PCB adapter, the PCB can be positioned further away from the connector. Depending on the conductor cross-section, distances from 10cm to 50cm between the power input and PCB are possible. With the alternative use of a PCB adapter for the power connection, it would be necessary to position the board parallel to the switch cabinet wall at a close distance in order to make the contact.

The Han-Fast Lock also enables the use of several connectors or an interface with various conductor cross-sections. The pinhole pattern on the PCB remains the same.

Han-Fast Lock features

• Allows high currents
• All connectors can be placed onto the board
• Flexible positioning of the contact connection points
• Leeway for positioning PCB in the device/switch cabinet
• Different termination cross-sections can be used in one interface
• Solderless process/ termination
• Standard production method
• Individual cross-sections can be combined
• Optimal heat management
• Quick assembly/non- destructive disassembly of the contact
• Unrestricted use of all contacts (phase/PE/ neutral conductor)
• Machine processing possible
• Standard B crimping
• Identical pinhole pattern with different connection cross-sections
• Can be used for different voltage ranges and PCB thicknesses

Harting USA
www.harting-usa.com

IMTS 2014 booth #E-4921

About the author: Frank Quast is the head of product management at Han/Harting Electric GmbH & Co. KG and can be reached at frank.quast@harting.com.