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PCB007-Aug2021

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44 PCB007 MAGAZINE I AUGUST 2021 by an engineer with both circuit design and manufacturing experience may save you more than 25% in long term costs. Another example is in yields. While it may be possible to build the circuit as you have it de- signed, a supplier with strong design for man- ufacturing (DFM) experience should be able to point out minor design changes that will in- crease yields measurably. For example, while a circuit may be able to be etched out of one- ounce foil, it may come at a reduced yield when compared to half-ounce foil. An experienced engineer should be able and willing to suggest materials based on the electrical and mechani- cal needs of your application. ey should bal- ance these requirements against manufactur- ability, allowing them to recommend materials that will be the most cost effective. Time to Market Let's face it, time is money. Say you are working for a medical device company on a new project. You are well-versed in circuit de- sign, so you decide not to engage with a circuit supplier offering DFM analysis. Instead, you think it will save time to work directly with a quick-turn house. Aer several weeks you re- ceive the product and install it in your device. e product meets your needs both mechani- cally and electrically. You think, "Great, this is working exactly as planned." Now it's time for another round of parts so you go back to the same quick-turn shop and order a couple doz- en more. e product is delivered, and it per- forms wonderfully. Teams are working in par- allel on the qualification process. What the sup- plier didn't tell you is that your circuit design and your drawing are in conflict. To achieve the impedance you are requiring, they use dif- ferent materials than what you had specified. e issue wasn't uncovered until a first arti- cle was performed on the low-rate production parts. Now the drawing and design must go through an ECO process that will take weeks. On top of that, the qualification process must start over, and you need to order more parts to perform FAI. Now the program has your team under the magnifying glass. All of this could have been prevented by taking a little bit of up- front time and working with a supplier that is willing to perform due diligence at the design review stage. Drawing Review Imagine you are a consumer electronics start-up. You work on a design and specify ma- terials that you are familiar with. is is based on a small volume application you worked on in a previous life. Aer months of develop- ment, you get to a point where you are ready for the big time. You send out for volume quan- tity quotes only to find out that two of the three companies you have solicited bids from come back with a no-bid. e no-bid is due to limit- ed material availability. e base material you have specified on your drawing is in short sup- ply and only available through a certain distrib- utor. e distributor has a sole-source agree- ment with the company you prototyped with. You are now le with the decision of stick- ing with that existing supplier at a higher pro- duction cost or redesigning your product so you can save money in the long run. You might think that you must be very specific when choosing materials that you call out on your drawing. is simply isn't the case. Material can be specified to meet the stringent require- ments of IPC, allowing your supplier to choose the materials that are the most cost effective and available. e flow down of a change noti- An experienced engineer should be able and willing to suggest materials based on the electrical and mechanical needs of your application.

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