DFA Reduces the Cost Impact of High-Reliability Connectors in Military and Aerospace Applications
The precision and performance benefits of custom connectors are brought within reach through design for assembly principles.
By Advanced Interconnections Corp.
Military and aerospace applications specify high-reliability connectors to meet performance requirements that lower-cost commodity connectors cannot provide. One of the ways to offset the additional expense of high-reliability (hi-rel) connectors is to consider how they could be redesigned to reduce overall applied costs. Utilizing custom connectors made with design for assembly (DFA) in mind can lower production costs by incorporating value-added features.
Unlike standard, off-the-shelf connectors, custom designs can be optimized for a specific application, taking into account performance and end-product integration requirements, as well as the assembly process. Rather than staffing or designing a production line to accommodate assembly challenges, connectors can be customized to reduce assembly time and even eliminate production steps.
For example, screw-machined terminals (sockets) with multi-finger contacts are often designed into military and aerospace products for their high-reliability performance in high shock and vibration environments. Instead of ordering loose socket terminals and assembling them onto printed circuit boards (PCB) by hand, a removable carrier can provide sockets or pins in the exact pattern needed (Figure 1).
Figure 1: This LED socket for high shock and vibration applications utilizes a customized Peel-A-Way Removable Terminal Carrier from Advanced Interconnections Corp. to reduce assembly time by eliminating the hand-loading of individual socket terminals.
Carriers can be flexible or rigid, hold multiple different terminal styles, and employ cut-outs to accommodate other components already placed on a PCB. By using a carrier, hand-loading steps are dramatically reduced or even replaced by automated pick-and-place assembly. Removable carriers offer complete solder joint visibility and improved air flow, and also improve quality by ensuring that the right pin goes in the right hole every time. Additionally, value-added features — such as stand-offs, guide pins, keyed and polarized shrouds, and even simple connector covers — can simultaneously reduce assembly time and improve production throughput by protecting delicate contacts, terminals, and leads during transportation and assembly (Figure 2). Further, the use of solder preform terminals can eliminate the need for wave soldering in a solder-reflow environment, like surface mount production lines where the only through-hole components are board-to-board connectors or device sockets.
Figure 2: Using design for assembly (DFA) to incorporate value-added features, including solder preforms, unique shapes, shrouds, covers, and stand-offs, turns the higher unit cost of custom connectors into an overall cost savings.
Selecting a connector supplier with the in-house capabilities to produce quick, cost-effective prototypes helps ensure that custom designs will meet an application’s unique performance and assembly requirements before investing in production tooling. Working directly with vertically integrated connector suppliers also allows customers to leverage the company’s product design engineers, enabling the timely development of prototypes that can easily be changed and optimized as the design of the end-product is finalized.
When amortized over the entire production order, the development costs for custom high-reliability connectors are often offset by savings realized during volume assembly. While the unit price of custom connectors may be higher than off-the-shelf options, proper design for assembly (DFA) considerations can significantly reduce the overall applied costs. The goal is to help OEMs compete by enabling the production of more cost-effective end-products without sacrificing performance or quality.
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