A PCB Design Potpourri


Reading time ( words)

In this column, I will be revisiting topics covered in some of my older columns and fleshing them out with new, updated information. In this job, I truly learn something every day, and I’m happy to share a few notable nuggets with you.

The Quote Process

Ultimately, whether it’s a quick-turn or standard lead-time job, customers would like to see all quotes back within a couple of hours, not a couple of days. Additionally, they want to see accurate quotes that take into account all additional processes. It’s never good when, once quoted, the fabricator comes back with additional costs for unforeseen processes. Again, this is why it is important to get a manufacturing review done if anything outside the norm is required on the drawing or quote. This includes a proper review of impedances to ensure that materials are available and the impedances work without requiring large variances in dielectric or line sizes, buy-offs for any deviations of material type or copper weights, etc.

Beyond the quote process, be sure that your fabricator is capable of all the processes necessary to ensure the board is built as expected. You want your board shop to be IPC-6012 Class 3 capable and ISO certified, and perhaps ITAR as well. Even if you can’t visit the shop for a physical qualification, send them a job to quote and see how they respond. A good fabricator will be diligent and get back to you within a few hours after completing a preliminary examination of the files, impedance calculations and proposed stackup if the board is impedance/dielectrically controlled. They should also be able to let you know right away if the job does not meet their process minimums and can’t be built. If deviations are allowed, a good fabricator will also have an alternative for many situations, such as a deviation for material type, starting copper weight, dielectrics or line sizes to be able to produce the job.

Read the full column here.


Editor's Note: This column originally appeared in the July 2013 issue of The PCB Design Magazine.

Share

Print


Suggested Items

TTM’s Approach to Stackup Design: Train the Customer

01/12/2021 | I-Connect007 Editorial Team
In this interview with the I-Connect007 Editorial Team, TTM’s Julie Ellis and Richard Dang drill down into stackup design, detailing some of the common stackup challenges that their customers face when designing for both prototype and volume levels, and offering advice to designers or engineers who are struggling with stackup issues. They also discuss why having too many different prepregs in a stackup can be asking for trouble, and how proper stackup design can optimize both the fabrication and assembly processes.

Chapter 1 Excerpt from the Book ‘Thermal Management: A Fabricator's Perspective’

12/08/2020 | Anaya Vardya, American Standard Circuits
Heat cannot be efficiently exchanged with stagnant air surrounding a hot device; however, it can be transferred away from the electronic component to the PCB using thermal vias. A thermal via is a good conductor of heat that runs between the top layer and bottom layer of the PCB, dissipating heat through simple conduction. In simple terms, thermal vias are plated holes located under, or electrically connected to, a surface-mounted heat source on a PCB that allows heat transfer through the hole.

This Month in Design007 Magazine: HDI Design, Landless Vias, VeCS, and More

11/09/2020 | I-Connect007 Editorial Team
Andy Shaughnessy, Happy Holden, and Dan Feinberg recently met with James Hofer, general manager of Accurate Circuit Engineering, to discuss via design techniques and via reliability from the fabricator’s viewpoint. As Hofer explained, even with open lines of communication between the designer and the board shop, there are plenty of variables to contend with regarding proper via design, especially when working with PTFE materials.



Copyright © 2021 I-Connect007. All rights reserved.