Lead-free PCBs may run into assembly problems
Comments by an engineer from printed-circuit-board (PCB) manufacturer, Exception PCB, suggest that replacing a leaded PCB with a RoHS compliant version is not enough to produce an effective and compliance product. “While a designer may be right to tick the ‘compliance required’ box on his submitted drawings, we are aware of instances where adopting the letter of the law and blindly adopting lead-free solders in isolation would be product suicide,” says Andy Hughes, a technical engineer from Exception PCB in an article on the Website, PCB 007.
Hughes notes that the laminates are the problem with lead-free PCBs. “Laminates – even those that pass the stringent FR4 test for quality – are generally unable to withstand the much higher temperatures required to work with lead-free solders. Hence, designers looking for the best quality boards – the FR4 standard laminates – would find their RoHS compliant PCBs suffering from the effects of Z axis expansion during assembly as well as potential board decomposition.” Hughes goes on to note that “Even if the boards survive the assembly process, the potential for failure in the field is vastly increased.”
MARK M. commented:
I have many issues with the lead /leadfree component mixes being placed onto leaded board assemblies. I also have customers who think that changing over to a RoHS fab is the anwser. Why doesn't anyone ask the right question? Should components be mixed on either leaded or lead free fabs? My Vote is NO!Problem - component manufactures have not fully converted! Who's left hanging? Process engineers!!! Does anyone out there have a solution to the mix? RoHs boards with an enig finish are tough to manufacture (more masking required to prevent fab damage during processing. Choose wisely when purchasing the cheaper fab, it will cost you more in the long run! Enough babble - have a nice day!
Mortis commented:
SCOTT: WHAT THE HELL IS RONG WITH YOU. WHAT IS A BOURD? IHOPE U ARE NOT DISINING ANYTHING THAT PEOPLES LIFES DEPEND ON.
scott bray from cpu automation commented:
ever since this this rohs stuff started and all my pc bourds i use have been reved to be rohs compliant NOW EVERY OTHER BOURD IS BAD , I,VE USED BOURDS THAT NEVER HAD PROBLEMS EVER AND NOW THE NEW (ROHS) VERSIONS ARE FULL OF PROBLEMS....I THINK ROHS IS CREATING A LOT OF SERIOUS PROBLEMS , SO FAR I HAVE HAD VERY BAD LUCK WITH ROHS COMPLIANT PRODUCTS AND THE WOSRT PART IS THAT ONCE A COMPANY REVS A PRODUCT TO ROHS STANDERDS THE OLD VERSION THAT ALWAYS WORKED WITHOUT PROBLEMS BECOME UNAVAIBLE.....BLAME IT ON THE UROS!!!!!
Fred commented:
So what is the answer? I have a board house we use telling me that a German company they make pcb's for use standard FR4 material with an ENIG finish. They have had no problems in the field.
I have another board house we use tell me that the chance of something happening later on to the standard FR4 or the high temp material's (FR406 & FR408) is to high. The answer is..........?
