In Part 1 of this blog, I introduced you to Mr. Phil Eckert, Samtec’s Quality Engineering Manager. Phil shared seven tips to help designers select the right connector system for their application, and to generally make your life easier.
Today, in Part 2, Phil gives us eight more tips to help you choose the right connector system for your design.
1. Flux: Unspent flux is problematic in connectors from both a mechanical interference and a corrosive nature. Ultimately this can result in product failures in the field.
2. Plating Tip #1: A SnPb finish is still the superior finish on solder tails and solder paste. Although there are possibly many restrictions, use it if you can. And use a nitrogen reflow environment as opposed to air; nitrogen is much better.
3. Plating Tip #2: In high reliability applications, thicker Au, more points of contact, and higher normal force are recommended. There is some truth to the old adage of “You get what you pay for.” Check the test reports for which plating style (Au thickness) was used to better understand the expected success of the connector in application.
4. Normal Force: Normal force has been called the “single best predictor of connector performance.” If given the option between two connector series and all other attributes are equal, choose the one with higher normal force. This is important in harsh environments and keenly important if the environment will experience temperature extremes or have high shock and vibration.
5. Ch-Ch-Ch-Changes: When selecting catalog standard parts, EOEMs have no control over changes to a connector, unless other agreements have been made. Samtec attempts to give customers advanced notice of any form, fit, or function changes, but there are the rare occasions where important changes are made with short notice.
6. Don’t Push It: Be cautious about using the connector in a manner more strenuous than what the manufacturer tested. If the test report lists 100 mating cycles, using the connector in an application with 150 cycles means you are treading into the unknown. In a case like this, it is best to ask the connector manufacturer for a recommendation. Don’t expect anything but a conservative answer. And if you receive an answer that sounds a little too optimistic, be careful. (Here’s a link if you want to see examples of Samtec test reports available)
7. It’s Probably Not Tested To Failure: Connector qualification testing was designed to match the expected conditions that the vast majority of users will subject the connector set to. It is not possible to test the connector to every unique application or to test connectors to failure.
If there is a unique application, it is best to ask the connector manufacturer for a recommendation. Expect a conservative, safe, recommendation. Some tests are significantly influenced by the weight and geometry of the PCB or assembly: shock and vibration testing for example. If you are interested in knowing when a connector will fail, expect to be asked to participate in custom testing.
8. Tape/Reel For Vacuum: Tape and reel pockets are designed for vacuum pick-up and not grippers. If grippers are used on pick and place equipment, specially designed pockets may be needed.
If you have questions feel free to contact Phil.