The Gerber Guide, Chapter 2


Reading time ( words)

It is clearly possible to fabricate PCBs from the fabrication data sets currently being used; it's being done innumerable times every day all over the globe. But is it being done in an efficient, reliable, automated and standardized manner? At this moment in time, the honest answer is no, because there is plenty of room for improvement in the way in which PCB fabrication data is currently transferred from design to fabrication.

This is not about the Gerber format, which is used for more than 90% of the world's PCB production. There are very rarely problems with Gerber files themselves; they allow images to be transferred without a hitch. In fact the Gerber format is part of the solution, given that it is the most reliable option in this field. The problems actually lie in which images are transferred, how the format is used and, more often, in how it is not used.

In this monthly series, I will explain in detail how to use the newly revised Gerber data format to communicate with your fabrication partners clearly and simply, using an unequivocal yet versatile language that enables you and them to get the very best out of your design data. Each month we’ll look at a different aspect of the design to fabrication data transfer process.

This column has been excerpted from the Guide to PCB Fabrication Data: Design to Fabrication Data Transfer.

Chapter 2: Alignment (Registration)

Never mirror or flip layers! All layers must be viewed from the top of the PCB, which means that the text must be readable on the top layer and mirrored on the bottom layer. Alas, sometimes, in a mistaken attempt to be helpful, designers flip layers because they must anyway be mirrored on the photoplotter. This could be helpful in a world where the designer's files are used directly in fabrication, but these data layers are actually input for the CAM system. This needs the correct 2.5D PC structure, so designers need to follow the standard protocol for providing digital data. The fabricator's CAM system will do the rest: it will optimise and panelise the PCB and on output of the final, panelised data, it will mirror, rotate, shift and scale as required by production. Any designer that mirrors layers can only hope that the CAM engineer notices this and ‘unmirrors’ them. 

To read this entire article, which appeared in the September 2015 issue of The PCB Design Magazine, click here.

Share

Print


Suggested Items

I-Connect007 Editor’s Choice: Five Must-Reads for the Week

10/23/2020 | Andy Shaughnessy, Design007 Magazine
After a crazy year like this, we shouldn’t be surprised that this trade show season is unlike any other. Here’s one of the many “silver linings” of 2020: We actually dodged a bullet earlier this year when COVID-19 hit after most of our industry’s big events had taken place. In this week’s top five, we have an assortment of trade show and conference news items, plus a few examples of technological trends and innovation.

Real Time with… AltiumLive Europe: 21st-Century Tools Keynote

10/22/2020 | Pete Starkey, I-Connect007
Good morning, Europe!” Altium VP of Marketing Lawrence Romine said as he introduced the European edition of Altium’s PCB design conference—established as an annual must-attend event, but for 2020 presented in a virtual format. Pete Starkey brings you the details from AltiumLive Europe's opening keynote on 21st-century tools and what's coming in 2021.

Real Time with… AltiumLive 2020: Early Communication Key to Success of OSV Project

10/21/2020 | I-Connect007 Editorial Team
Rob Cooke, director of engineering at Calumet Electronics, discusses his role in the Open Source Ventilator (OSV) project that yielded ventilator PCBs in record time. He and project partners, Dugan Karnazes of Velocity Research and Chris Denney of Worthington Assembly, recounted this story during a panel at the virtual AltiumLive.



Copyright © 2020 I-Connect007. All rights reserved.