Sourcing Mil/Aero/Defense MS style connectors

April 20, 2018

When should you consider designing in and sourcing Mil Spec vs. Commercial equivalents (and vice versa)?

Since owning ECCO, an electronic connector authorized distributor specialist, I have been overwhelmed with questions as to when, why, and how our customers determine which connector, style, and brands to put on their prints, and subsequently into their final products.  In the next few paragraphs I will examine criteria for determining when it is most appropriate to specify Mil-STD/Mil-Spec style products over commercial counterparts.  Additionally, I will offer a list of questions to consider when approaching a design where both types may be options. I will also give you an example of worst case situations that have recently occurred when dealing with this often considered and often misunderstood sourcing decision.

First, let’s define what a Mil Spec connector is, and then define its commercial counterpart.

Wikipedia definition is:

Connectors used by U.S. Department of Defense were originally developed in the 1930s for severe aeronautical and tactical service applications, along with Type “AN” (Army-Navy) series set the standard for modern military circular connectors. These connectors, and their evolutionary derivatives, are often called Military Standard, “MIL-STD“, or (informally) “MIL-SPEC” or sometimes “MS” connectors. They are now used in aerospace, industrial, marine, and even automotive commercial applications.

The commercial counterparts of MS style connectors are often made of the same materials, usually with exacting specifications and measurements.  Sometimes they come off the same production lines at the same factories with the only variance being the marking of a part number.  While not always apparent or disclosed, if this in fact is the case the pricing should be very similar. However, supply and demand may dictate variances as well in the pricing of either part.  In fact, if the part is a commercial call out and there is not another manufacturer on the print, the supply could be limited, competition for bidding limited, and the market’s price could be higher than its MS cousin.

However, there are times when commercial equivalent connectors are justifiably lower priced. This happens most often when a material change is made (e.g. when contacts have less gold content or a plating process changes a spec). This allows for lower material costs and thus a lower price to the end customer.  Additionally, if the commercial product is produced at separate factory with lower labor costs it could also result in a final lower price.  So, in several of these instances there is a very good reason for a commercial part to be designed into an application if cost is an issue and there is no MS requirement from the end customer.  Here is a good time to reflect on the DLA Stop Shipment issues that were well publicized last year as noted in an EPS article epitomizing a worst case situation:

Taken from EPC March 31^st, 2016 article, Gina Roos reports: Buyers of mil-spec connectors could face short supply of certain mil-spec products due to recent stop shipment orders issued by Defense Logistics Agency (DLA) Land and Maritime. DLA issued stop shipment orders to a few large connector manufacturers in March and February 2016, for several types of mil-spec connectors due to sourcing components from unapproved facilities. Subsequently, DLA issued a stop shipment order for all affected mil-specs on March 1. These include MIL-DTL-22992, MIL-DTL-26482, MIL-DTL-26500, MIL-DTL-27599, MIL-DTL-38999, MIL-DTL-55302, MIL-DTL-83513, & MIL-DTL-83723 series of products.

These stop shipment orders significantly impacted the distribution channel. Industry sources say this could be “catastrophic” for the supply chain if the issues aren’t resolved quickly.

Ultimately, when it comes to deciding on MS vs. commercial equivalents, the answer in any sourcing situation is “IT DEPENDS”.

It depends on…

1. Does the customer demand MS approved connectors? If yes, you only have to determine brand(s) to evaluate and place on print (2 always recommended).
2. If the customer can use either product, determine if your application can take the relaxed technical specs of a commercial equivalent, and ask if those specs are a result of material, process, or labor aspects to the commercial equivalent of the MS connector.
3. Pricing must be considered so get quotes on both the commercial and MS approved parts, determine if the market for supply and demand is driving commercial pricing higher than MS style.
4. Your company’s strategy for supplier approvals may dictate your vendor choices so make sure you know who has demonstrated supply success in that connector category. Consult with other stakeholders such as purchasing, production, engineering & product management to verify there is support for any given supplier.
5. Is “available inventory” at any given time a consideration as there exists a plethora of military style comparable products on distributor’s shelves and sometimes not as much of the commercial equivalents.

As a note, many of us authorized value added connector assemblers have the ability to dual mark a part “commercial” or its “mil spec” equivalent if, in fact, they are the same exact parts.  Therefore, it will be important for any customer to know when this can be done because it offers greater flexibility to sourcing.

Lastly, when confronted with this sourcing decision, just ask anyone of us assemblers who are QPL’d (qualified product listed) for these connectors. We are experts and here to help you through this process.