Issue link: https://iconnect007.uberflip.com/i/1467185
32 DESIGN007 MAGAZINE I MAY 2022 board is extremely involved. Additionally, it helps for designers and fab engineers to have a solid working relationship. If the designer and fab engineer are working together for the first time, when the fab engineer has a ques- tion about the design, he will typically call the contact person (oen a project manager or purchasing person), who will connect him with the designer. is is where a great fab engineer who asks unpleasant questions is indispensable. Unfortunately, things may change, and the designer may not know who will be fabricating the part or even assembling it. For instance, the chosen fabricator may have a long lead time or some other previously unforeseen complica- tion. In this case, the part may have to go with another fabricator. Please note: When this happens, if the job is controlled impedance, it is a good idea to have the new fabricator run the calculations to see if there will be any large trace or space swings that result in a redesign. is includes things like increasing traces when you've already designed to the minimum space allowance. Other hurdles, such as choosing a different material type (due to supply chain issues), may result in a complete redesign, which, unless you are a glutton for punishment, is not so fun. Likewise, the designer may have an idea who will be assembling it, and he may not. is is where I get on my soapbox. If you genuinely want to make sure something gets done, com- municate it clearly. Shaughnessy: Why do so many designers not know who is going to manufacture their boards? Thompson: I can think of two reasons. e first reason is company culture. If the designer works for a company that has a purchasing depart- ment that does not share information about where the part will be fabricated, designers must ask probing questions. Companies today have numerous design and engineering meet- ings where this information can be shared, but frequently it is not, for whatever reason. I see no reason a purchasing person would inten- tionally withhold information regarding the selected fabricator, but it could happen. Remember that if cost is their sole reason to choose a fabricator, you get what you pay for. If a job requires multiple respins due to a fab- ricator's lack of quality control, you have lost more than just time. I think that a thorough company will always share such information with the designer and engineer on that proj- ect, especially if there are any specific items to be passed along to the fabricator relating to the success of the part. ere is one other possible reason for designers to be le in the dark about the cho- sen fabricator, also related to company cul- ture: Sometimes, the purchasing person may not care where the part is fabricated, provided the result is as anticipated, and the cost and lead time are good. To me, this leaves a lot on the table, with the potential for miscommuni- cations about the expectations and net result. What may be a "simple" board to a designer may be less than simple when it reaches the fabricator. Mark Thompson