August 10, 2022

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What Occurs When You Assume?

What Occurs When You Assume?

What Occurs When You Assume?

Once we began planning a latest difficulty of Design007 Journal on design with manufacturing, or DWM, we knew we would have liked I-Connect007 columnist Dana Korf to weigh in on this new acronym, and what true DWM would appear to be in operation. On this interview, Dana explains what it can take to realize complete communication amongst all of the stakeholders within the PCB growth cycle. He additionally stresses the necessity for everybody concerned in PCB design and manufacturing to cease making assumptions, even on the danger of being labeled as “that man” who asks too many questions.

Andy Shaughnessy: Dana, we’re listening to extra speak about design with manufacturing, or DWM. For all of the speak about DFM, communication among the many designers, fabricators, and assemblers simply doesn’t occur as usually as we would anticipate. In your opinion, what does true DWM appear to be? And the way can we get designers and producers to embrace it? 

Dana Korf: Once I first heard about DWM, I assumed it implied we have been at present designing with out manufacturing. I’m not clear what it truly means as a result of that’s what we’re doing at the moment. I’ve simplified the issue into three components. First, the fabricators don’t present all of the design guidelines that front-end engineering makes use of to guage a design for his or her prospects. In some firms, the method engineers received’t inform the front-end engineers all the principles.

Second, the information switch we’re utilizing relies on an N/C method from the Fifties, with a whole lot of information, and other people need to unintelligently guess what the information is meant to be as an alternative of utilizing extra clever codecs like IPC-2581 or ODB++. Neither clever format is ideal, however they’re positively higher than Gerber-based packages. Third, the design software can’t make the most of the fabricator design guidelines even when they have been supplied. 

I did a design evaluation a few years in the past with a tier one software program provider. I discovered that even when they have been supplied all of the fabricator design guidelines electronically, they’d nonetheless need to carry out a whole lot of scripting to include a lot of the supplied DFM guidelines. A standard instance I give is the minimal area between a conductor to the sting of a board. Is the sting scored? Is it routed? Is it punched? How are you making this? These have completely different units of guidelines, most definitely, and the design doesn’t essentially have the correct guidelines as a result of the design system doesn’t have information of how the sting might be created. 

Through the years, we’ve simply accepted this drawback. Within the `70s after I first bought into this, we hand-taped paintings on Mylar. They photographically lowered it all the way down to the right dimension, they usually constructed it. It was fairly easy. Then we invented CAM instruments. That was the place we went downhill, together with the primary producer who stated, “I’ll repair your design at no cost.” That’s when design information high quality went downhill. 

Pleased Holden: Sure. I’m unsure that DWM is definitely actual, as a result of who in manufacturing has that type of time to dedicate to a buyer?

Dan Feinberg: My first thought is: Do you design for manufacturing, or do you design for the efficiency of the gadget? What comes first when you have got to choose between value and reliability?

Korf: Proper. There are two issues for me. One is that board fabricators will not be chosen till after the design is finished, they usually’re chosen by procurement or the EMS firm. They exit, supply it, then choose the suppliers on the finish of the format. You don’t know who you’re designing for. I train a DFM class for IPC, and one of many issues I train is the IPC definition of DFM. It’s one thing alongside the traces of, “Design for optimum value to manufacturability,” and I add, “and meets the design intent.”

To your remark, Dan, you’re actually attempting to make the board work first after which guarantee it’s producible. Value is definitely third, as a result of if all of them come again they usually don’t work, you’ve misplaced all of your cash anyway. I train college students that if you happen to’re going to design for a producer, determine whether or not it’s the correct one for you. Not each fabricator can construct each functionality, and never everybody has the identical set of design guidelines for a given know-how. That’s a part of the issue, too. We’re chasing value/worth together with high quality and efficiency. It’s a triangle; the previous saying is that you would be able to solely get two out of three of these.

Shaughnessy:  It appears like a whole lot of these points arose out of outsourcing. None of this occurred through the time of captives.

Korf: That’s proper. Once you had in-house manufacturing, the manufacturing unit may very well be tuned towards the product and all the things was optimized. You had lots much less variability, lots higher probability of getting good designs out, and getting them proper the primary time. However, even then, they nonetheless had information errors.

To learn this complete dialog, which appeared within the June 2022 difficulty of Design007 Journal, click on right here.