Fixing a break in the defence supply chain

According to Charcroft’s product specialist Chris Leek, restoring the continuity of supply after a break in the defence supply chain needs specialist distribution skills.


The recent withdrawal of a manufacturer from supplying circuit breakers for defence applications has highlighted the specialised distribution skills needed to maintain supply continuity. In fact, this manufacturer will not even supply commercial circuit breakers for use in defence applications.


The easiest option is for the distributor to find a drop-in replacement or close alternative with the same physical size, voltage and current rating. Unfortunately, some breakers no longer available for defence applications have no direct alternatives.


For breakers rated up to 500A, the most cost-effective solution may be for the distributor to offer an alternative from a different manufacturer by adapting an existing breaker to carry 500A.


In addition, a high-vibration version of the standard 2TC circuit breaker has been engineered by circuit breaker manufacturer, Sensata, by changing the standard 7/16in neck thread to an M12. Another solution was provided by adapting the breaker fixing. The replacement had the same size and current rating as the original but a slight change to the front panel was needed for fixing.


The need to find replacements for high-reliability components goes further than circuit breakers and extends to capacitors and resistors.


As defence applications often have lifetimes measured in decades rather than years, the ability to identify and deliver a replacement for an obsolete passive can be vital. This can mean the difference between having defence equipment operational or sitting in a workshop waiting for a costly redesign.


Charcroft uses in-house manufacturing to customise a solution for an individual customer and deliver a replacement passive with the same form, fit and function. UK manufactured specials include custom passive assemblies to meet tough electrical, mechanical and environmental specifications for challenging or retrofit designs.


In-house processes can help overcome a range of supply-chain challenges, including screening a batch of passives which are rated for five per cent tolerance to select out individual components with two per cent tolerance.


The defence supply chain must meet the immediate need to supply the correct component and deliver long-term support throughout the extended lifetime of the defence equipment. By developing a customised computer system, plus quality-led sales processes, Charcroft has been designed to support the special needs of defence and other tough applications.


Immediate needs are supported by ensuring that the appropriate grade of component is quoted  and supplied for each application and that a certificate of conformity (CofC) is included with every shipment. A copy of every CoC is archived, so the customer can request a copy to address a question which may arise longer term.


An archive of internal customer part numbers is also maintained. These are sometimes used by defence customers in place of the component manufacturer’s original part number. The archive can identify the original part number and help identify a replacement if the component becomes unavailable or obsolete. An archive of decades-old legacy datasheets adds to resources available to identify a replacement for a legacy passive.


Having supported the defence customer from the point of supply and through the component and equipment’s lifetime, the distributor must also look to the future. This means sharing knowledge of emerging components entering the defence market.


One of the latest components is a potential game-changer. This new ultra-high energy, surface-mount film capacitor is 90 per cent lighter than the MLCC capacitor it can replace. A new high-frequency clock oscillator adds ultra-low sensitivity to acceleration, plus low phase noise, and is designed for high shock or vibration applications.


A flexible approach can be extended to long-term and stabilised price agreements. An agreement can be reached with a customer to provide a stabilised price and hold inventory for a component for the length of the pricing agreement.


While mainstream distribution will supply components to the defence market, it takes a special set of distribution skills and processes to deliver the knowledge and resources to fix a break in the supply chain.