Fasteners and Sealing
5. What materials should I look for in a rugged connector?
Traditionally, the toughest connectors are made up of nickel-plated brass. Today, however, aluminium and stainless steel, and even some composite plastics can be specified and still fall into a rugged connector category.
rating of 24 hours at 120 metres. You also want to understand whether the IP rating is for the connectors in a mated and/or unmated condition.
9. Where do I get cable assemblies for my rugged connector?
Rugged connectors need to have equally rugged cable assemblies in order to work in tough environments. Medical device manufacturers often look for silicone cables with low-friction coatings. Very few OEMs attempt to make cable assemblies in-house. Most turn to a specialty cable assembly provider or to their connector manufacturer to recommend specific cables, over-moulds and assemblies that will create a rugged interconnect solution.
Fig 2. Fischer Connectors has a wide range of circular push-pull connectors.
6. Can rugged connectors be sterilised? High temperature (including steam autoclave), chemical and radiation sterilisation methods all require rugged connectors that can withstand the sterilisation process. Each sterilisation method has its own connector requirements, so be prepared to discuss exactly how the end user plans to sterilise your finished device.
7. How are rugged connectors sealed? Sealing typically falls into two categories: environmental sealing against dust, water and other minerals, and hermetic sealing against gasses. With environmental sealing, an interface seal protects the junction between the two connectors, keeping harmful particles away from the connection area. Mounting panel seals, seals for protecting the contact areas, and cable sealing round out the areas that are needed to protect the connector and the connection. Sealing materials include Viton, a fluoropolymer with low permeation and excellent chemical resistance. EPDM (ethylene propylene rubber) is commonly used for interface o-rings that are designed to be mated and unmated in low temperatures. Hermetically sealed connectors are traditionally sealed with glass, ceramic inserts, or epoxy.
8. What role do IP ratings play? IP ratings measure the level of protection against dust, dirt and water. Look for IP68 ratings or above for true waterproof connectors. Most IP designations have specific conditions, but IP68 ratings should be defined differently by each manufacturer, so be sure to ask what the rating represents. There is a big difference between an IP68 rating of 2 hours at 20 metres and an IP68
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Fig 3. The Fischer UltiMate Series of rugged connectors.
10. What type of lead-time do I need for my rugged connector?
Like any other product, lead times will vary, based on what you order. Popular-sized connectors are often available off the shelf and can be ordered quickly. Creating a custom connector that is unique to your application could take 12-16 weeks. Modifying an existing connector design falls somewhere in between. The best connector solutions are specified early in the design process so that you have the time to select the right size and weight connector solution for your application, possibly allowing you to build a smaller, lighter device. ●
For more information ✔ at
www.engineerlive.com/ede
David Cianciolo is Director of Engineering of Fischer Connectors USA, Greater Atlanta. Fischer Connector is headquartered in Saint-Prex, Switzerland.
www.fischerconnectors.com
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