lead free?

[spuffock]

Over the last year or so, it seems that the incidence of crystalline failure, as distinct from dry joints, has much increased. I,m sure you've all seen them, there is a complete circular fracture around the pin, with a distinct crystalline appearance. Usually found on joints subject to vibration or heat. My questions are: Has anyone else noticed this, or am I just getting paranoid, and, if they are on the increase, are they the fault of lead free solder ?
What do YOU think?

 

[Nigel Goodwin]

Over the last year or so, it seems that the incidence of crystalline failure, as distinct from dry joints, has much increased. I,m sure you've all seen them, there is a complete circular fracture around the pin, with a distinct crystalline appearance. Usually found on joints subject to vibration or heat. My questions are: Has anyone else noticed this, or am I just getting paranoid, and, if they are on the increase, are they the fault of lead free solder ?
What do YOU think?

They have always been common in TV sets, if anything the change to lead free has probably reduced them?.

 

[stevez]

solder

A friend knows of my electronics hobby and passed along several technical articles a few years ago, relating to problems with lead free solder. These articles described crystalline features and whiskers that appeared over time with the lead-free solders. I don't recall if process adjustments or solder chemistry was to blame or was the solution. Note that my friend works in the space industry where really little things were a big deal.

 

[dknguyen]

Weird

Thats weird. Lead-free solders have the advantage of being stronger and more heat/vibration resistant than lead-free solders. They are harder to work with so maybe the solder wasn't properly used or not heated up enough?

 

[stevez]

process change

I think with any significant material or process change there is a learning curve that has to be climbed, so to speak. I am old enough to remember when water based paints became available and popular -now they are mandated. Everyone said the new stuff would never replace the old stuff. Once they worked the bugs out things were better. Same with plastics - plastic used to be a sign of cheapness or imitation - today in many applications its superior.

I used to work for Kodak. Their customer base was enormous. Every time we made a subtle change we had to listen for reports back from the customer. We could test all day but there's no better test than the marketplace. Certainly some hard lessons are learned that way.

Good to hear from you.

 

[Jack Luminous]

I've read about this 'whiskering' phenomenon, but have yet to witness it firsthand.
I also heard complaints that lead-free solder joints are more brittle and susceptible to fracture than lead/tin joints.

I've been using lead-free for about two years, and aside from the higher temperatures needed and the fact that it is a bit more difficult to get it to flow, I haven't noticed any problems crop up on any of the boards I used it on.
Desoldering the lead-free stuff can sometimes be difficult for me.

I've seen mentioned (on another forum) something about how you should only use lead-free compatible components with the lead-free solder.
Don't know if that is true, but here's where I read it if anyone is interested:
https://www.diystompboxes.com/smfforum/index.php?topic=38774.0
Scroll down a bit to find that comment.

 

[dknguyen]

Lead

I have heard that too...most places now use a matte lead finish though which should be compatible. And they are narrowing down lead-free alloys for use in solders that is compatible with lead. It shouldn't be too much of a problem.