Pete,

  Very good points, thank you.

 I would add this through:

  Two job functions that are important to the defining of PCB design rules (and data) are Pick and Place (PnP) operators and PCB rework operator. But, the people in these positions are typically incapable of translating their work experience into meaningful requirements that can be passed into engineering disciplines. Worse yet many PCB designers have never even seen paste applied to a board much less have they pasted boards themselves. Same goes for PnP operation, how many PCB designers have operated a PnP machine for 2 weeks? How many for 2 minutes?

 Enter the role of management. One would hope a manager (as in VP of Engineering) could facilitate this transfer of information and thus reduce engineering level of effort and costs all while improving product quality. But it does rarely happens. Why? The reason is most engineering managers have almost zero skills with the software, data and assembly processes. They lack the ability to effect change into the various stages of engineering activities. Most of the folks who are VP of Eng. Are only in that position because they have been with the company a long time, that is often a negative indicator of ability.

 I am also a bit grumpy about this. It destroys otherwise perfectly good companies not to mention all the Bad Karma generated.

 So, how can a lowly PCB designer do a VP of Engineering job? One of two ways, either it is enforced by power coming down from above or the PCB designer can gain the trust and support of the other folks in other departments. (Good luck on either solution.)

If a company can't change in a marketplace defined by "Innovate or Die" then the outlook is not good. This goes double for the engineering departments.

 I am open to ideas. 

Bob K.


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pete
Sent: Wednesday, October 19, 2011 8:56 AM
To: [log in to unmask]
Subject: Re: [TN] SMD Component spacing guideline -- help required

This question would probably be better answered on the IPC Designers Council listserver.  While there are some good ideas being posted here, there's a lot to be said for the many years of experience gained by people whose primary job is PCB design. 

Do not use software packages auto generated outlines, they take into account nothing related to PCB assembly and rework.  Likewise, using Silkscreen and hoping will not work.  Find out what your pick and place and rework processes require, use those in developing design rules.  Our library carries 3 outlines - 1 silkscreen, one actual MMC size, one placement courtyard.  As general rules, our process requires .5mm between components, an extra 1.5mm for components taller than 3mm, an extra 3.2mm around BGAs for inspection.  Those are just general guidelines to start with, when placing the board you have to add your knowledge of how a board goes together.

Please, don't take that as derogatory, the PCB designers gain that information by communicating with the types of professionals that populate Technet, but as the question was posed from a design aspect, it might be better answered that way.

I'm a bit grumpy about this.  I am the only PCB designer in a RFID company of 3000+ employees.  Management has decided that pretty much anyone can design PCBs, they laid off all the other designers.  So almost all of our products have been missing market dates by months, even years, not meeting performance specs, manufacturing costs are increasing, and field failures have gone up.  I spend all of my time correcting problems, not designing anything.  Just minutes ago, I viewed CEO message lamenting our 4th missed quarter in a row,  the ONLY answer is more workforce reductions, I believe there's a good chance I am viewed as expendable, since "we have other people who can design boards".  And another good company bites the dust from mismanagement.

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