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Who worries about component placement on your designs?

Catwell
All jobs I've had management delegated all the component placement off to an in-house drafter of some sort. My most recent project, I was in charge off every step; from design to manufacturing. I wasn't formally trained in component placement, so I embarked on a crash course in the subject. I learned quite a bit about the importance of trace widths, component proximity, and emi considerations.

Now in retrospect, I feel that the drafters of my earlier jobs had no idea what they were doing, and that is why I had so much difficulty with prototypes. In particular, I remember a VLSI audio codec chip I worked with had so much trouble working. Now, after learning a bit about PCB layouts, I realize that the drafter did not place several support components close to the processor.

So, I am wondering: did anyone learn about component placement in college, or was it more of a afterthought, on the training familiarizing? Do you take component placement into consideration? Or, do you trust that "weird drafter guy, in the off to the side cubical," to lay out your design properly?
 
C

  • Hi. This is almost an out-sourcing management question! If you do it yourself, you have only yourself to blame if it goes wrong, but can take the credit when it goes right. However once you outsource, you still take the blame but may get the credit (or people might just say "Hey, that contractor is good!").

     

    If you are at all worried about the component placement and circuit design, then you need to specify most everything in the design outcome that you want - component placement, trace width, pitch, corners, ground planes, etc. You can't assume that the outsider will know. I recall my first experience of this, under am engineer who was also experiencing it for the first time. The board designs came back all over the place, total rework. And this in the days of hand-laid tape: no small ask. Eventually we learned enough of what we wanted that we decided to do it ourselves. I guess that qualifies for "on the job training".

     

    Some years later I farmed out a job myself for the first time - total disaster, all the same reasons. You forget that not everyone knows what you're thinking, or has had the same experiences. Since then I've been using various shades of Protel and never needed (or wanted) to outsource a design. I place components manually then let it do an auto-route, then invariably "tidy it up". There are always funny curly bits, unecessary spurs etc that can be removed manually. With busses I do them as a group before letting the auto-route work around them. Again, this is bitter experience at work rather than formal training but I cherish the OJT I had under experienced hands many years ago, when we used tape. You HAD to be careful and methodical in those days, and it paid didvidends. My most complex job was an eight-layer backplane board - right first time (but after very careful peer review before manufacture!).

     

    I haven't seen any formalised courses at College/University in my part of the world which deal with more esoteric design/placement issues, but that's not saying they aren't there. What I have seen tend to be fairly fundamental and revolve around being adept at using particular packages. Experience is a great teacher.

     

    Cheers!

  • in reply to Former Member

    Ken,

    Thanks for the stories. I'm glad I am not alone with this issue.

     

    In the current job market, in the USA, PCB layout positions are in abundance. But most people just graduating college have almost no experience beyond a breadboard or perfboard. And to get said PCB jobs, you need 5+ years experience. A catch 22 if I've ever seen one.

     

    Perhaps it's time to re-institute the apprentice in the work place. Fledglings learning from the "masters," so to speak.

     

     

     

    Anyone know where you can get classes on PCB layout?

     

     

     

    Ken, perhaps you can host some seminars on the subject on the side. Just a thought.

     

    Cabe

  • Hi Cabe,

     

    I like to think that the design process is most efficient when the electrical engineer draws the schematic, does the placement of the critical components and sometimes even routes the critical tracks (placement and critical trackes are very much related). The layouter's job is to finish the routing (less critical tracks) and make sure that the product fulfills the manufacturing rules. The layout is the knowlegde keeper on all the factory/process guidelines/rules. In this case the path to a succesfull first PCB (good enough to send to your customer) is more assured. Assuming ofcourse that the circuit is first breadboarded or silmulated. If this is skipped, the first PCB will have a lot of reworks (wasting time / money)

     

    I agree that experience is key. If your layouter is 'fresh' you have to sit next to him and guide him a lot. This add to his knowlegde. I'm lucky to have a very experienced layouter, so most of the time i leave all the copper artwork to him, but i have to check the design at the end anyway. It is good to have standard checklists.

     

    Best regards,

     

    Enrico Migchels

    Power conversion design engineer

    Heliox B.V.

    Best - The Netherlands

    www.heliox.nl