|Ask the Experts|
August 15, 2017
Lead-free bar solder for wave soldering
We are about to switch over to lead-free wave soldering. I was wondering if there are any technical articles comparing the quality of bar solders from different companies? What is the most widely used product for lead free bar solder?
|Expert Panel Responses|
Can't help with the solder bar issue but Lead Free Intrusive Reflow is a process which eliminates the need for wave soldering. I can email you a copy of a recent article presented at APEX 2007 on this subject.
Vice President Technology
There is not any testing that I am aware of comparing brands of lead free solder. However there are a lot of test comparing alloys. The first lead free wave solder used was SAC305 however there is a trend to move away from high silver alloys to no silver of low silver alloys. There are several conditions that need to be prioritized, copper dissolution rates, appearance ( grain structure), wetting, voiding, and maximum temperature requirements. All of these come into play to choose a lead free alloy. The largest move has been to Sn/Cu + alloys. Additives (+) can be Ni, Co, Bi, Ag to mention the most popular additives. I have my favorites as do most of the people responding to your question.
Deck Street Consultants
At this time, the solder with increasing market share in wave applications is tin-nickel-copper, such as SN100C from Nihon Superior. I don't know if there is any published data on which lead-free solder is the most widely used.
CEO & Managing Partner
Although I've seen many companies who have switched to lead-free soldering in their wave solder machines, I've not seen any internal comparative analysis results from these operations. This phenomenon of comparative analysis used to be a common occurrence during the Tin/Lead soldering operations however I would imagine that with the various patented alloys today, the comparison is not so much evaluating the differences between suppliers but understanding the differences between the alloys. Since many of the lead-free alloys are patented, one would have to contact the vendors or suppliers directly to get any information about their particular alloy combinations and operational profiles. As for which of the alloys is most widely used, IPC and iNEMI have recommended the use of SAC 305 alloy, while the Japanese manufacturers are recommending the use of Sn100C solder. They both work fine, but users have to do the reliability work to determine which is best for their process and products. Hence, experiments are still being conducted and the results are still being developed to create an overall industrial application of these alloys.
Vice President, Technical Director
|Submit A Comment|
Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.
Insert Your Email Address