Design007 Magazine


Issue link:

Contents of this Issue


Page 51 of 83

52 DESIGN007 MAGAZINE I MAY 2018 Last month, I began my new series of col- umns on resins by selecting five frequently asked questions from our customers regarding resin chemistries and properties, and typical resin applications and their limitations. This month, I'm taking this introduction a step fur- ther by listing what I believe are the top five tips for circuit designers and manufacturers who seek to ensure that the reliability and lon- gevity of their electronic assemblies and prod- ucts are fully addressed. Think very carefully about the sort of envi- ronment your PCB is likely to encounter. It is easy to over-engineer a product so that it will survive the very worst of conditions, but worst conditions may only be fleeting or transient. Therefore, a resin solution with a lower temperature performance specification will often cope. Take temperature extremes, for example. Your application may experience occasional temperature spikes of up to 180°C, which you might feel deserves treatment with a special resin. However, such excursions may only be short-lived; under normal operating conditions, the PCB might only be subjected to a maximum temperature of, say, 120°C, open- ing a wider choice of resin types and methods of application. In a similar way, the required chemical resis- tance of your chosen resin will depend on the duration and/or extent of the chemical contam- ination. For example, there is a considerable difference in terms of the extent of chemical damage between a thin layer of a contaminat- ing chemical on the resin surface that is wiped off within five minutes and 500ml of chemical present on the resin surface for one hour or more—let alone complete immersion! Further- more, the range of chemicals that a PCB might Protecting PCBs from Harsh, Challenging Environments Sensible Design by Alistair Little, ELECTROLUBE 1

Articles in this issue

Archives of this issue

view archives of Design007 Magazine - Design007-May2018