Page 12 - ConnectorSupplier.com - How-to-Specify Handbook

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factors have a signi cant impact on the assembly equipment and manufacturing processes as well. So, specifying engineers should consult with their manufacturing and design groups before making a nal decision regarding termination type to ensure that they’re making the best overall choice.
Sealing
The next step in the rugged connector selection process is evaluating the end-use environment of the connector. If the connector will be used in harsh operating environments, specifying engineers must check the ingress protection (IP) ratings of their options to ensure that their selection delivers proper sealing performance against dust and water ingress across various depths, conditions, and operating timeframes.
Most IP designations have speci c conditions, but individual manufacturers can de ne the IP68 rating differently. So, when searching for a connector with an IP68 sealing rating, it’s critical to nd out exactly how each manufacturer’s IP68 rating is measured. For example, a system submerged at 2 meters for 24 hours will have a different impact on the connector than a system submerged at 120 meters for 24 hours, but both situations can be de ned with an IP68 rating.
Additionally, for vacuum and instrumentation applications, engineers may want to consider connectors sealed to even greater levels than are de ned by traditional IP ratings: airtight hermetically sealed products.
Materials
Next, specifying engineers will need to address materials and reliability needs, noting that these decisions will directly impact how small of a connector they can ultimately select. Since these factors are inextricably intertwined — with smaller connectors requiring stronger materials to handle application requirements — some tradeoffs in terms of material selection and size may be required.
Selecting the right housing material is supremely important, as this factor impacts the reliability, weight, and cost of the overall connector. Brass connectors with nickel/chrome plating are traditionally more wear-resistant and have longer lifecycles than many other materials and, if weight is an issue, aluminum connectors are an attractive option. Brass and aluminum are the most preferred materials for miniature rugged connectors, and plastics are preferred for limited-reuse and disposable applications. Although, when considering plastic, it’s important to conduct adequate testing to con rm that the material will withstand the rigors of the end-use application and, when specifying plastic connectors for medical applications, to con rm that the connector can withstand any application-speci c sterilization processes. Additionally, when specifying for aggressively corrosive environments, as well as some food industry applications, stainless steel may be required. Ultimately, though, the primary rule of materials selection is: Don’t sacri ce reliability for cost.
At this point, speci ers should also review the operating temperature range for the insulating materials used in the connectors they’re evaluating. This includes contact insulators, potting materials, and O-rings. Tables 2 and 3 can help with this selection process.
Reliability Needs and Connector Characteristics
Once a connector’s electrical and data transfer design has been declared protocol compatible, and its termination, sealing, and material requirements have been addressed, it’s time to consider how frequently users will connect and disconnect the device over its lifetime. High mating cycle applications call for connectors with durability ratings in the 5,000 to 10,000+ cycle range. This selection is especially important if a failed electrical connection can put lives at risk, such as in medical or military environments, but may require tradeoffs with regard to miniaturization, as miniaturization often means fewer mating cycles.
Table 2