CONNECTORS
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To source a suitable connector, it is important to fully know your needs from the voltage and number of estimated mating cycles to sterilisation requirements.
(Photo courtesy HYPERTRONICS) |
Define Technical Needs
Medical device companies in the market for connectors should make a list of their requirements including basics such as current ratings, the number of circuits and which system components need to be connected, according to the medical engineering and business development team at Hypertronics Corp. (Hudson, Massachusetts, USA). They also suggest that medical device companies note the voltage to be used, both between contacts, and between contacts and the outside world.
It is important to determine functionality, says Christoph Buob, Product Manager of Schurter AG (Lucerne, Switzerland). Buob suggests looking for a single, complete component with approved functionality as opposed to multiple components needing separate approvals. “You also must consider safety concerns such as parts that have touchable live wires,” he adds.
Other considerations to keep in mind include disposability, the estimated number of mating cycles and compliance with DIN EN 60 601-1, says Günter Rohr, Director of Marketing and Sales at ODU Steckverbindungssysteme GmbH & Co. KG (Mühldorf, Germany).
Consider Lifetime Reliability and Safety
The number of mating cycles that a connector can withstand is something to consider when assessing a connector’s reliability, says Serge Buechli, Product Manager, Lemo SA (Ecublens, Switzerland). To be reliable, the connectors also must be shock resistant and impervious to wear and corrosion. Another consideration, according to Buechli, is contact resistance, which is expressed in milliohms. This value should be constant over time to ensure the electrical contact and correct reading of medical instruments and probes, he says.
Diane Cupples, Vice President of Marketing at Schurter stresses the importance of avoiding risky features, citing as an example connectors with fuseholders that can be removed without a tool. To avoid accidents during operation or replacement, she suggests looking for “extra-safe” fuseholders that require the use of a tool for fuse removal.
Know Your Accessories
It is important to be aware of the type of cable your product will use, stresses Buechli. He suggests noting the cable’s outer dimension, how many wires it contains and the diameter of each conductor. He also recommends noting how much current will need to flow through the cable and the connector, and whether specific impedance is necessary when using a coaxial or triaxial cable.
When electromagnetic compatibility filters are required, leakage current is an issue. “In general, medical appliances allow a leakage current of 100 µA,” Buob says. “Depending on the stray capacity of the system, different filters can be selected that differ in leakage current.”
Consider the Effect of Sterilisation
Medical device companies should consider if the connector or cable can withstand repeated sterilisation cycles, Buechli says. “Autoclave and steam sterilisation are very hard on the plastics of the connectors,” he notes. For applications requiring sterilisation, he recommends using a connector with a polyetherimide shell rather than one using polysulphone.
Choose the Right Vendor
Because connectors are used in an array of diagnostic systems, choosing a connector that precisely meets your needs is often difficult, Rohr says. He thus advocates doing business with a company that can develop custom products. Work with companies that have global manufacturing locations, advises Tim Beck, Product Manager, Tyco Electronics (Middletown, Pennsylvania, USA), because they tend to offer fast delivery and competitive pricing.
