Solder Defects and Continuous Improvement

Phil
Welcome to Board Talk. This is Jim Hall and Phil Zarrow, the Assembly Brothers, Pick and Place, from ITM Consulting.

Jim
Phil I'm looking at the responses and questions from our readers. We get an awful lot of questions about solder defects. Is that telling us something about what's going on, generally, in the industry?

Phil
Yeah I think it really does. And I got to tell you: at least these guys are asking the questions. I got to grant them that. How about all the others that aren't asking? This is something that just pulls my rickshaw. The fact that there seems to be complacency out there, "I'm okay to live with mediocrity," the idea, "Oh, a certain level of defects, that's okay. Don't fix something that's not really broken."

Well it is broken, damn it. This whole thing flies in the face of what you and Dr. Ron and I are always talking about, LEAN and continuous improvement. This is the opposite; I don't get it. I mean people are actually maintaining inventory in preparation for building scrap. This is insane. How did we evolve to this? Where did this come from?

Jim
Well perhaps people don't like to admit their mistakes, so they hide the rework people off in the back corner. We see this all the time - we deal with this very frequently in our consulting activities. People don't measure the defects; they don't keep totals, they don't keep accurate numbers: "Oh, it's hard!"

I think one of the problems is they don't want to know; they don't want to deal with DPMO, defects per million opportunities, percent first pass yield. They're taking first yield after you do touch-up. All these things contribute. I think it's just hiding a problem.

Phil
Yeah, I agree. I guess you could say these people were in denial or something here.

We have something we call the consultant's dilemma. To paraphrase our Car Talk Brothers, but basically we feel like we're mechanics. One of the things we have in common with them. This is what we typically see. People have a defect problem: "Maybe if I ignore it it'll go away," like putting duct tape over the Check Engine light or turning the radio up to hide a sound.

Then they go a little further: now it's starting to get a little bit more severe, kind of swerving from side to side, hitting the curb, things like that: "Well, let's try to fix it ourselves," oh, finally getting to do something. Sometimes they succeed; a lot of the times they don't, and it gets worse. And then maybe they'll call in the consultant.

But anyway, it's that first thing, that complacency, where they're living with a certain level of defects. How do we get this way? Is this an indictment of our society and our whole culture?

Jim
It's not unique to the United States.

Phil
And a lot of people settle for, "Well, you know," and they send this stuff overseas, cheap labor, and "Yeah, you got to expect a certain lack of quality." Why? Why are you settling for mediocrity?

All right, I'll calm down now.

Jim
But please continue to send in your comments and your suggestions and even if they are solder defects, but we'll try to get back to you. Thanks a lot.

And speaking of soldering. Don't solder like my brother.

Phil
And don't solder like my brother.

Jim
And keep the kids away from the flux pot.

It's all about the resources. Some times your designs are not supported by your equipment. You do the best you can with what you have. It would be great to live in the world of no limits, but it is not so.

Solder defects on others words is lack of process knowledge and control of the input critical characteristics KIV, and of couse following the internal procedures, as Jerry Maguire said on the movie Show me the money (show me the data ) and I can make Improvement.

I think there are several factors that may be at work here. There may be a cultural factor, which was eluded to in the piece. There may be a resource factor, not enough expertise to go around.

However, we shouldn't overlook the "continuous advance of component technology factor". As we become comfortable with 0402's, and micro-BGA's, here come 1005's, QFN's, and .075 pitch through hole arrays, etc, etc.

As component technology advances, a complete re-engineering of processes may be required to keep defects under control. So, at least from my perspective, the advance in component technology is the most critical factor promoting soldering defects today.

I think it's companies who set themselves up to get mediocre results in manufacturing. They lean up their workforce so much that it's impossible for the engineering staff to manage it all.

I'm the Process Engineer for 5 SMT lines, which have 6 pick and place machines, 5 ovens, 5 printers. On top of that, I'm also the guy for our through hole dept which includes 4 selective soldering machines, component prep, wash, and hand soldering. I have an Engineer who is just now taking over the printing process and data collection for the SMT area, and an Engineering Tech who helps in both areas.

I have DFM projects constantly, ongoing process validation, new process investigation, RoHS, REACH, and a slew of other things like that that have my constant attention. Now, don't get me wrong, I know I have tremendous job security, but in reality, it's more work than 3 people can do so things slip.

We hit the major defects, not the spikes mind you, but the consistent, lower hanging fruit that does "weekly or daily" damage.

When I worked for HP (pre-Agilent), they had an Engineer and Tech for every SMT and Through Hole process. They might be an example of what having "Fat Engineering Resources" was, but defects were very low and continuous improvement was very obvious and focused on.

I think it boils down to the resources your company can commit, in other words: You get what you ultimately pay for.