submersion), particulate matter exposure, as well as the application itself. Due to these limitations, the end-product cannot truly be considered ruggedized. Heat-shrinkable boots may be appropriate for certain interconnect designs as they are engineered to promote moisture- and dust-resistance and protect cables from corrosion and mechanical abuse. They do not, however, create a true seal between the cable and connector, or encapsulate the terminations. Shrink boots are available in off- the-shelf sizes, shapes, and in a limited choice of materials, making them well suited for the most basic interconnect applications. Additional alternatives, such as 3D printing, may minimize particulate and moisture ingress. However, overmolding provides the maximum level of protection and durability to definitively ruggedize interconnects.
ENVIRONMENTAL CONSIDERATIONS The injection molding process has become progressively environmentally friendly. New automated CNC milling stations now require 50% less energy than machines from as little as 10 years ago. Though there is still overmold plastic residue, it is appreciably less than the amount created by most other manufacturing processes. Additionally, the composition of today’s overmold materials and interconnects are optimized to extend the products’ useful life and are increasingly fabricated using recycled substances. Eco-friendly methods of disposal and carbon footprint are similarly considered. Notably, the European Union’s Restriction of Hazardous Substances (RoHS) Directive requirements for ruggedized overmolded interconnects are based on application and whether parts are to be used in another product. There are important permanent exclusions: military and space applications, large-scale industrial tools or fixed installations, transportation, and equipment outside the scope of RoHS. While these requirements and exclusions are not interconnect-specific, they are contained within the RoHS compliance guidelines.
ALTERNATIVES TO OVERMOLDED INTERCONNECTS
MIL-Spec interconnects, plus those listed or retained on a Qualified Product List (QPL) or Qualified Manufacturer List (QML) are sometimes suitable in select applications requiring ingress resistance. They ordinarily are comprised of mechanical seals requiring end-user assembly and exact cable conformance (jacket material and roundness). Seals are rated for an exact method of liquid (spray vs.
MIL-Spec interconnects provide a predetermined level of liquid and particulate ingress protection but cannot be considered ruggedized.
THE FUTURE OF RUGGEDIZING INTERCONNECTS THROUGH THE OVERMOLDING PROCESS
Overmolding will remain the most reliable and cost-effective method to ruggedize mission-critical
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