EVERYTHING YOU NEED TO KNOW ABOUT LEAD-FREE SOLDER

Lead-free solder alloys have been garnering quite a lot of interest in the industry, particularly after the advent of the RoHS and WEEE directives that are focusing on ridding electronics manufacturing industry from the use of lead as a vital raw material. Traditional tin lead soldering techniques have been designed to suit the specific needs of the alloys that are no longer in compliance with RoHS.  Lead-free soldering requires managing a whole new set of variables. Here is everything you need to know for creating reliable and viable solder joints for your circuit board using Lead-free  alloys.

·         Lead-free alloys have a much higher melting point than its traditional tin lead counterparts. This means all your process steps and materials must be tweaked/modified to withstand the high temperature requirements of lead-free soldering.

·         Various flux varieties are incapable of sustaining through the increased temperatures necessary for soldering with lead-free alloys. It can get charred and coat your soldering tip and other circuit board surfaces, making re-tinning virtually impossible.

·         The appearance of your solder joints will also change with the switch-over to lead-free alloys. While the result of tin lead alloys is a shiny and even surfaced, the lead-free versions will appear to be duller and coarser.

·         Higher melting points of lead-free alloys means extended dwell times as the wetting process will take a bit longer to complete. You will therefore, have to tweak your soldering operations accordingly.

·         Another factor to take care of when using lead-free alloys is the possibility of bridging and creation of tin whiskers. You will need a lot of practice at handling the soldering iron to ensure the above issues don’t creep up and disrupt the circuitry of your board.

·         Lead-free alloys are also more prone to oxidation owing to the higher temperature they need for becoming wettable. The flux application and surface cleaning steps in your soldering process will therefore, have to be tweaked accordingly.

Keep the above factors in mind and you won’t face any issues while using lead-free alloys for your soldering needs.

KNOW HOW TO USE ROSIN SOLDERING FLUX PASTE

The quality of the soldering joint produced depend majorly on the minor soldering process details. Activities like cleaning the printed circuit board properly and using the right flux are crucial for efficient soldering. After reading this blog, you will know how to use rosin soldering flux paste.

                

Step #1: Getting the right tools

The size of the actual area available on printed circuit board components for soldering can be very small. In order to accurately apply rosin solder flux paste onto such small areas, you need the right tools. Something with a fine tip, like an ice pick, can do the trick for you.

Step #2: Cleaning things up

An unclean printed circuit board is the root cause of ineffectiveness of flux. To ensure that the rosin flux is able to do its job properly, clean the printed circuit board thoroughly.

Step #3: Applying with care

Use the tools you gathered to apply a generous amount of rosin solder flux paste onto the points to be soldered. Try to avoid wastage of flux by keeping your hands steady as you apply.

Step #4: Heating

You can proceed with the soldering iron over the surfaces you just painted with rosin solder flux paste.

Paying attention to the little details while doing precision work will help greatly in achieving flawless solder joints.

COMMON MISTAKES TO AVOID WHEN USING THERMAL CONDUCTIVE PASTE

There’s a bit of a trick for everything, even with PCB assembly processes that follow an otherwise straightforward and to-the-point approach. This blog post has been designed with a similar standpoint – a glance into the common mistakes that should be avoided when using thermal conductive paste. With factors listed here, you can prevent various process issues and make your overall operations much more productive.

Mistake# Ignoring electrical conductivity

While thermal conductive paste is available in various varieties like diamond based, silicon based, carbon based and ceramic based compounds, metal based paste is widely considered to be the most suitable, owing to its excellent thermal conductivity parameters and affordable price. However, metal based compounds also have an inherent capability of carrying a charge which can end up damaging your PCB components if left unaccounted for. So, if you are using a metal based thermal conductive paste, make sure you do not apply it in too copious quantities.

Mistake# Not cleaning the surfaces before application

The reason of applying thermal conductive paste is to remove irregularities and lessen the distance between the circuit board and the heat-sink, to ensure a better, cleaner and a more constant connection between the two. Therefore, while applying the paste, you should make sure that both surfaces are completely free of contaminants, dust, dirt, grime or any other form of residue. The most common method used to clean surfaces is rubbing alcohol which can carefully remove all impurities without causing any damage to the board and its components.

Mistake# Applying too much or too little paste

Too much thermal conductive paste can detract from its effectiveness and performance as a thick layer will increase the distance between the circuit board and the heat-sink, thereby hindering the heat transference process. Too little paste will also not fulfill the purpose as air pockets and gaps will remain behind. The idea is to apply an even, optimal layer of paste, covering as much surface area of the board as possible.

Use the above information to tweak your method of thermal conductive paste application and get the most from your device performance.