Progress to a Modern Format
I emphasized in an article EETimes published in October that OEMs could streamline PCB fabrication and thereby save time and expense by submitting designs in the ODB++ format, or better yet in the IPC-2581B format when the software becomes widely available. The point of the story is that unless PCB manufacturers become better advocates about the advantages of the intelligent file formats for conveying PCB designs from CAD tools to fabrication and assembly, designers will continue to rely on Gerber files despite the limitations.
There’s no dispute among PCB manufacturers that the way customers compile and send most board designs for manufacture–a collection of Gerber RX-274X files that graphically define the layers, bundled with a drill file in Excellon format, a netlist in IPC-D-365A format, a stackup and board drawing in a PDF or two, notes for the build in a Word document, for assembly a BOM in Excel format and a file of coordinate data for pick-and-place operations—is hardly ideal, considering the alternatives.
Both the immediate alternative, ODB++, which has been available for 15 years, and IPC-2581B express all the design information in one format in a single consolidated database, easing verification and transfer of the data to CAM. ODB++ and IPC-2581B are XML-based formats with a rich set of attributes to thoroughly describe layer features, in contrast to Gerber files, which define the outlines and locations of features without further explanation. That is why ODB++ and IPC-2581B are called intelligent formats. Recently, the company responsible for the Gerber format, Ucamco, updated it to include pad, via and other feature attributes.
Though PCB manufacturers agree that a modern protocol for conveying design data would improve production, there’s no consensus about which format to favor. Sierra Circuits advocates IPC-2581B, but like most companies welcomes orders in any format. I highly recommend a great blog by Ben Jordan of Altium that really delves into the situation and elicited nearly two dozen replies internationally.
One response in particular underscores what we face: “When will our industry learn that multiple standards for the same task are just a way of delaying technical progress?”
Let me know what you think in the comments. I’m eager to hear your opinion.