Retronix Blog

Nov 18, 2016

Why Pre-Tin Components?


Lots of electronics companies pre-tin their components before fitting to the PCBs and this has become the standard to these companies, it is often viewed as “something we’ve always done” and this has led to less people understanding the real reasons behind why this process was first introduced to their company.

Essentially by pre-tinning you are adding a layer of protection to a component. But there is so much more to it than that…!

Helping your operators create a more reliable solder joint, anyone that has ever soldered a component to a PCB will tell you that a good finish on both the PCB pad and the component leg is essential to a well formed and reliable solder joint.

Assisting with solder flow thru on thicker multi layer or copper heavy PCBs.

Removing oxidisation and other contaminants from legs before fitting to the PCB. Contaminants and oxidisation on component leads can cause many solderability issues including cold solder joints.

Protection from oxidisation when storing components for extended periods of time, this is more and more important nowadays to industries that suffer from component obsolescence and, as a result, are buying high quantities to store for extended periods to ensure the future of their product.

Components with gold lead finish have to be pre tinned before soldering to your PCB, this is to aid solderability and to avoid gold embrittlement risk in the completed solder joint. (see image below).

 

This practice has been in place for many years and is proven to help with all the points raised above, in fact, tinning was my very first job in the electronics industry, a scary 24 years ago….! for 8 hrs a day I was pre-tinning all types of components for an avionics and antenna company who pre-tinned every component before it went into stores to be picked for kits.  As far as I am aware that company still undertake this practice to this day.

Retronix offer tinning services from single pre-tinning to a “Double Dipping” tinning service for high reliability and high stress environment electronics.

Double dip tinning is suitable for more reliable solder joints in harsh environments; eg. where heat and vibration exist. Double dip tinning suppresses oxidisation short term and therefore produces a much stronger solder joint during assembly.

Alongside the standard tinning and the double dip tinning services, another tinning service that Retronix offer is Alloy Conversion Tinning – the ability to take a full BOM from a customer and convert from PB to Rohs compliant or from Rohs compliant to PB.

Talk to Retronix about your pre-tinning needs, or contact me directly – rob.ronan@retronix.com