Issue link: https://iconnect007.uberflip.com/i/1101604
28 DESIGN007 MAGAZINE I APRIL 2019 full of overlapping methodologies—is hardly in circulation because it's expensive. So, iron- ically, the PCB industry is likely developing NC files based on non-existent, illegal, incom- prehensible, or unaffordable specifications. And when it's not, CAD software is reverse en- gineered from the clutter of existing NC files. XNC So, where do we go now as an industry, given that we're not yet ready for Gerber drill files? Fortunately, there's a new format for PCB drill data that takes all the confusion out of CAD software development and the CAD-to- CAM drill data exchange process. Designed by Ucamco, KiCad, and PentaLogix with the sup- port of Graphicode, Cuprum, and ZofzPCB, XNC is a strict subset of the widely used NC format. We believe that the first step towards impro- ving the NC drill chaos is to develop a sim- ple, clear specification without embellish- ments—one based on an existing format that can be read by all decent PCB drill in- put software. To this end, we have taken gre- at care to design the CAD/CAM Exchange NC (XNC) format—a complete, compact, and une- quivocal subset of IPC-NC-349 that is capable of exchanging CAD/CAM drill information without the need for additional sidecar files. And we've added to this the power of Gerber- type metadata or attributes. XNC attributes can be attached to the complete file, tools, or individual holes, describing characteristics in a standard, flexible way using similar syntax to that used for Gerber attributes. XNC files are compatible with Gerber X2 and can be added seamlessly to X2 data sets while also ensuring that the format is compatible with software that does not read attributes. With XNC, CAD developers can create output software easily and quickly, using formats that are already well known but without the head- ache of having to wade through and choose from a bewildering array of possibilities and function- alities, or reverse engineer from multiple in- complete and confusing NC files. We guarantee that if CAD developers limit themselves to using just the XNC format, they will give their clien- ts exactly what they need—a tight file format that will improve the CAD-CAM data transfer process overnight, and an NC reference towards which the industry can work so that NC files converge to a common standard. Conclusion Existing NC drill data CAD-CAM transfer processes are deeply flawed thanks to confu- sion at every level of the CAD and CAM in- formation development process due to in- dustry inertia and inappropriate data format specifications. A lot of time and resources are being wasted by CAD software developers try- ing to make sure that every eventuality has been accounted for in their software, CAD profes- sionals delivering irrelevant and non-standard information about their designs, and CAM engineers interpreting the results. A new drill data exchange specification designed by some of the industry's leading PCB software provid- ers and based on an existing and known NC format promises to alleviate many of the issues and pave the way to a new industry standard for NC formatting and files. The first version of the specification of the XNC format can be found here. DESIGN007 Karel Tavernier is the managing director of Ucamco with 30 years of experience in software and imaging equipment. Denis Morin is a software application engineer on Ucamco's European support team. Jean-Pierre Charras is the founder of KiCad, researcher at Laboratoire des Images et des Signaux, and a professor in electronics engineering and image processing at IUT in France. Marius Matioc is the creator of Lavenir CAM software and head of product development at PentaLogix.