Ask someone if they are interested in environmentally sustainable processes and you’ll see a lot of chest thumping and hear a lot of rhetoric about how we have to save the world.
Then ask them what PCB finish best approaches sustainable ideals and you will hear how ENIG is pretty close and HASL isn’t all that bad. In truth, one of the best approaches available today is Immersion White Tin. As a shop that offers and truthfully prefers Immersion White Tin for its lead-free and environmental pluses, Omni Circuit Boards is pleased to provide this finish for its niche market of Prototyping and Short Run Printed Circuit Boards.
Mention Immersion White Tin around salespeople from PCB shops who do not offer the finish and you are likely to see eyes rolling and enough talk about whiskers you’ll swear someone changed the topic to ZZ-Top. They may not feel comfortable down mouthing the competition in public but a process? Well that’s fair game. What the salespeople don’t know or won’t tell you is the Immersion Tin used as a finish for circuit boards completely dissolves in the solder used in the circuit board assembly process. Considerable research is out there to show whiskers which do occur are mainly from the tinned leads of installed components or from lead free solder. Another great way to ensure you won’t have any issues is to have your PCB manufactured at a knowledgeable shop with in-control finishing processes. Which is just one source of pride for us at Omni Circuit Boards.
Besides sustainability, Immersion Tin is also able to offer:
- Greater flexibility with fine component pitch requirements
- Less press fit restrictions particularly on boards with thicker substrates
- A uniform, flat and dense solderable surface that is desirable for surface mount components
- Processes which require lower Power and Water consumption to produce, which you may not appreciate when you have your boards in-hand, but we do.
As more and more manufacturers embrace lean manufacturing concepts, the need for storing bare boards for multiple years also declines. At Omni, we are seeing more and more examples of multiple reorders of lesser quantities and shorter intervals as manufacturers align supply with demand. This in turn ensures rapid turnover of material and lessens the chance of shelf damage which will occur eventually to any PCB finish.
How do we know we are backing the right process? Well, for starters, we regularly supply contract manufacturers directly and in many cases Omni and our Immersion White Tin finish is the preferred supplier. Due to the properties of Immersion White Tin not found in other finishes, we also have new product development customers who have let us know if we drop Immersion White Tin they will find someone who does offer it. Using our knack of always looking at the bright side, we prefer to think of this as an endorsement of our finish rather than a lack of brand loyalty.
So how did Immersion White Tin turn into the Red Headed Stepchild of PCB finishes? In our humble opinion, part of the reason is a lack of sustained marketing and information campaigns from the suppliers. The market leader for Immersion Tin Chemicals, Enthone in particular, has superior products and yet their sustained marketing presence is severely lacking. It is akin to Bayer releasing a wonder drug and leaving the pharmacists to market it to doctors and patients.
According to some sources, Immersion White Tin and Organic metals will become the unequivocal finishing process as worldwide environmental legislation will ban its contemporaries. In the meantime, Omni Circuit Boards will extol the virtues of Immersion White Tin but should you send us an order with ENIG or HASL, we’ll still execute on it. In the end, the customer is always right, at least until Immersion White Tin is globally adopted.