Surface mount fasteners

Assembly Automation

ISSN: 0144-5154

Article publication date: 1 June 2005




(2005), "Surface mount fasteners", Assembly Automation, Vol. 25 No. 2.



Emerald Group Publishing Limited

Copyright © 2005, Emerald Group Publishing Limited

Surface mount fasteners

Surface mount fasteners

Keywords: Surface mount technology, Fasteners

Penn Engineering Fastening Technologies has developed ReelFast, a system that uses surface mount technology to add fasteners to printed circuit boards.

The system adheres various types of fasteners directly onto a solder pad on the surface of the PCB, using the same soldering process as the board's electronic components (Figure 1).

Figure 1 The ReelFast demonstrating its ease of assembly

These new fasteners have been designed with productivity in mind, as they have to work with surface-mount assembly machines. As the name suggests, the ReelFast parts typically come in tape-and-reel packages suitable for use with existing pick-and-place robots.

The ReelFast SMT fasteners minimise the damage to PCB's, as they are placed during component population, not after. Broaching fasteners are inserted into PCB's after population, which can subject boards to significant amounts of stress when they are at their most expensive. ReelFast gives another option to the designer when addressing the board fixing issue. ReelFast parts also eliminate secondary fastener installations, reducing cost.

Once installed onto the PCB, the ReelFast hardware exhibits performance characteristics equal to those of an equivalent broaching fastener. A ReelFast retaining nut installed into a 6.35 mm hole has an average pull-off strength of at least 375N, and an average torque-out strength of 3.7N/m. In the same test, a comparable PennEngineering broaching style fastener achieved a push-out strength of 420N and torque-out of 3.9N/m. In both cases, the circuit board delaminated before the fastener failed.

The first ReelFast SMT product to be released is a surface-mount version of a PennEngineering panel fastener. The fastener consists of a metal retainer that adheres to the PCB and a plastic cap-and-screw is snapped into place by hand.

This ReelFast SMT Panel Fastener is ideal for applications that require a PCB to be easily removed and replaced. Thread sizes for ReelFast panel fasteners include M3, M3.5, #4-40 and #6-32. The panel fasteners also have a cosmetic benefit in that the colours of the thermoplastic screw cap can be customised to match chassis colours.

PennEngineering will soon release ReelFast SMT versions of its stand- offs. For applications where PCB removal is not required, the SMT stand-offs will be a lower-cost alternative to panel fasteners. Following the ReelFast SMT stand- offs, a SMT version of the “R'Angle” right angle fastener will be released.

For further information visit the web site:

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