Interlocking Material Management and Quality

Estimated reading time: 8 minutes

Johnson: It would seem that you also get traceability: When it comes time to trace potential causes of field failures or assess the quality feedback loop, you now have much more information to work with.

Benoit: Absolutely. When the information is registered, and I get a recall notice from my component supplier, the system can quickly determine the impact: Which boards had those lot codes? If it hasn't left the factory, I can pull it. If it has left the factory, I can narrow my recall down to a much smaller number.

You might recall the Samsung Galaxy Note 7 disaster from 2016. It was a battery defect, not a PCBA component issue, but the lesson still holds. Samsung couldn't confidently isolate the affected population, and even their replacement units failed from a second defect. So they ended up recalling and killing the entire product line, costing billions. With component-level traceability, lot and date codes tracked through assembly, you can scope a recall to just the affected units instead of torching the whole line.

As an aside, I actually had one of those phones, and it overheated on me while I was traveling in China. I had to cool it off in the sink before dumping it in the trash. It's the kind of failure a customer never forgets, which is exactly the point.

Johnson: In the paper, you talked about this idea of “interlocking,” which I hadn't thought of it in that way before. Can you tell me more about that?

Benoit: We’re all familiar with what happens when you’ve got the wrong material for the product that you're loading. That situation is typically caught and handled by the setup verification software on the placement machine. In other cases, you find quality issues with certain materials you don't want used. In a good material control solution, you would flag those materials as quarantined, and then say, "Don't allow these to be used."

If the system is integrated with the placement machines, for example, now I can block the material by doing a process interlock that says, "This material is quarantined. We won’t build any product until it's removed."

What if a material expires? If it's a moisture-sensitive device, there are complex rules (floor life) about how long it can be exposed to outside moisture. If something goes past its floor life, you want that item blocked as well. In these cases, while it's nice to warn an operator that a part is wrong, you want to trigger an interlock and force a line stop until they remove the part.

Johnson: I'm imagining a moment on the shop floor where a reel of components gets marked “quarantine” on the spot. That reel just happens to be in use on a line, and as soon as they hit the quarantine status, a red light immediately goes off on, say, line four, and everything shuts down because that part is there.

Benoit: That's exactly the idea. The light tower turns red, a buzzer sounds, the machine stops, and it cannot start again until that reel is removed and replaced with a better one. That's exactly how it works.

Johnson: That's powerful. I can understand now why your automotive customer from Europe could get to zero excess inventory. Greg, how should we wrap up this conversation?

Benoit: We see people at all different maturity levels, if you will, in material management. Maybe you have some of these systems in place, but they're not necessarily tied together. Maybe you've started, but you don't have the unique ID, so you’re struggling at the batch level and everywhere in between. Give us a call and let us help. We will move you further along the path toward a full solution. We look at your current situation, find the gaps, and help you plan a complete, mature solution.

It happens in stages, of course. It takes time and money, not just for purchasing software. It could mean changing processes and doing retraining. We meet our customers where they're at, and develop a workable roadmap they can tackle in stages. It doesn’t have to be a big-bang approach just to have full visibility on the shop floor.

Johnson: I once worked at a prototype PCB fab where we took the 25-year-old homegrown ERP/MES and built it in Visual Basic, stitching together a mix of legacy software the company had accumulated over the years. We replaced it with a modern out-of-the-box system customized to our specific business. Now, as a prototype shop, half the fabrication business is 24- and 48-hour turns. There was no opportunity to take the factory down for a week.

We had to hot-swap the old and new systems. One minute, the factory was running on the old system; the next, it was running the new one. The controller put it best when he said, “This project is like removing a complete skeleton from the body, putting in a new one, and not killing the patient.”  It worked, but we had to really be thorough and careful about how we switched from one system to the other. Outside expert help was crucial.

Benoit: That's why we’re modular with our solutions and approach. There's only so much change an organization can absorb at any given time. We always implement in a way that's manageable, with bite-sized pieces to get them where they need to go over time.

Johnson: Greg, thanks for all the insight.

You can download the two-part Cogiscan white paper, Strategies for Efficient Material Management in Circuit Board Assembly, from our Industry Resource Center: Part 1  and Part 2.

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