Posts Tagged ‘Dry Baking’

What damage does the assembly process do to a pcb? (part 1)

Wednesday, August 17th, 2011

A colleague contacted me the other day with a topic that would make an excellent post on this blog.

“How can we solder boards with a Tg of 180°C or even 200°C at temperatures of 225-245°C without damaging the board?  Even with leaded boards the peak reflow temperatures are way above the board’s Tg.  How is this possible?”

The answer is simple. Every time a printed circuit board is exposed to soldering temperatures it becomes damaged. This is the case not only for Lead-Free soldering applications but also for eutectic soldering consisting of tin-lead.

Tg is one of several parameters to be aware of. In the case of Tg most designers refer to the value as (more…)

Dry bake test results.

Saturday, August 29th, 2009

Printed circuit boards shall absorb moisture to the point of equilibrium. This shall occur as long as there is a source of moisture. Relative humidity provides an ample source of moisture for the absorption process. It is common for contract manufacturers to maintain a controlled environment that often relies on humidity to minimize static charge build up. Electro-static discharge (ESD) is damaging to assembled electronic components. Humidifiers are employed to maintain a 50% relative humidity environment. However, in minimizing one problem another is introduced. The humidity that is introduced to minimize ESD is absorbed into the printed circuit board and components alike.

In a production setting on a manufacturing shop floor, (more…)