Issue link: https://iconnect007.uberflip.com/i/1424540
14 SMT007 MAGAZINE I NOVEMBER 2021 er it. Like bypass caps using an AOI solution to pick up that electrical test, we're not going to cover that. Maybe on certain types of BGAs boundary scan, an X-ray may be a solution that you don't have nodal access to because fly- ing probe and AOI may not be able to pick up those coverage or points. Matties: I heard you were talking about the schematic. So, the earlier you can be involved in the design, the better? Horner: Right. Again, it's getting the test engi- neer involved in the design sequence, even if it's just to supply the design-for-test rules to the designer so they can put it into their librar- ies and their models when they're laying out a board. Some of that stuff can be automatical- ly incorporated. If you can get 60–80% of that done up front, then when the EMS and the test engineers are involved in setting up the test strategy on that particular assembly, it can be set up for success. Matties: Bert, you provide test services to whoever wants it. Where does outsourcing fit in on test strategies and how does that help an EMS provider? Horner: From an OEM point of view, the de- sign-for-test review up front can help the de- signer incorporate the testability at the earli- er stages. At the EMS level, the test engineer or the test development service can offer guid- ance on a test strategy. Most EMS providers are armed with a knowledge base of test engi- neering, whether they have an in-house guru or they have a fairly competent staff able to do that. But as far as incorporating a third par- ty like ourselves, we get involved in the earli- est stages, even at time of quote, where we're spelling out test plans and test strategies. It's not uncommon for us to say, "Hey, give us a preliminary or a predictive test coverage," at the time of quote. Matties: Are you working with the OEM at that point, or are you working with the design- er or EMS company? Where's the first contact made? Horner: Both at the EMS provider and the OEM. e designer, if they're handing that off and they don't have a particular EMS provid- er picked, or even if they do have one picked, they will leverage somebody like us and incor- porate that test plan at time of review. And at the EMS level, at time of quote, we're also be- ing incorporated in a boundary scan and flying probe, or we do AOI and flying probe, which are predictive coverage. So, we're brought in on both levels. Matties: And how important is the cost factor and the testing strategy? Horner: It costs a little bit of money to set up a test strategy, but you save money downstream. So, if you're going to build 100 boards, you may be looking at the test plan and test strategy and the testability review and be a little concerned on the pricing. But when you have a bone pile of half, a third, or even 10% of the boards and there's not a test solution to detect where the fault is, what's that product worth at that level? Matties: Right. It's a balancing act, for sure. Horner: Balance is having a budget to say, "Our test plan up front is going to cost us this much From an OEM point of view, the design-for-test review up front can help the designer incorporate the testability at the earlier stages.