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40 The PCB Magazine • February 2014 from rounding. The time and effort required to extract a complete PCB product model from the Gerber, drill, netlist and document-information is significant. Success is achieved through a combination of a completely-defined format, tools that work with it, and an organization behind it that sup- ports customer deployment and ensures the for- mat's vitality. The ODB++ format supplies the fabricator with a complete set of data. The files contain not only stackup information, but drill- ing, masking, net data and a wide range of in- telligent attributes that make separate drawings unnecessary. The complete manufacturing-level definition of the product is contained in one self-contained file structure. Figure 1 graphi- cally demonstrates the advantage of supplying ODB++ data to the fabricator instead of the out- dated Gerber-type data. The low failure mode and effects analysis (FMEA) means that the quality of the fabricated board is also improved when using the full capability of ODB++. It's important to note that a complete ODB++ file set is necessary to take full advan- tage of the automation capabilities of the for- mat. This is best realized by defining a com- plete data transfer process. This process should include DFM analysis to check the fit of the product to the intended manufacturing pro- cess, and full communication of all appropri- ate attributes in the file set. Submitting just a partial file set to the PCB fabricator will not allow him to take advantage of the significant intelligence that ODB++ is capable of provid- ing. Once the full set of files has been speci- fied, those files should then be compressed as a single .tgz file for the fabricator. Fabrication software automatically recognizes the .tgz file and understands the file structure and how to use those files. Advantages for the Fabricator There are good reasons why vendors such as Viasystems, a provider of complex multi- layer PCBs and electro-mechanical solutions to OEMs, based in St. Louis, Missouri, are fond of intelligent ODB++ data. It saves the company front end time, money, and allows a faster re- sponse to the customer. ODB++ helps ensure on-time delivery of a high quality end prod- uct. Gerber data, on the other hand, requires a multistep workflow just to get a set of data from which the PCB fabrication-process preparation can proceed. At any place in the workflow, they may dis- cover errors or omitted data, which can mean multiple communications with the customer to correct errors or get additional data. On av- erage, about 25% of the data packages they re- ceive have issues related to: • Missing layers, fabrication drawings, drill files, etc… • Netlist format violations • Netlist exception violations Kent Balius, Viasystems' VP of global front end engineering, has collected extensive data to support his preference for ODB++ over any oth- er format: "Standard Gerber input takes us one to two hours just to import, analyze and prepare data for production CAM tooling. While ODB++ SMART DATA TRANSFER FORMATS AUTOMATE CAD/CAM continues table 1. ODB++ Benefits for the PCB Fabricator 1. import and export diagnostics are significantly reduced compared to Gerber 2. errors can be identified and communicated to the customer much earlier in the process 3. eliminates format errors and net exceptions that are common with Gerber 4. Fabricator can be allowed to see actual net name used by customer, easing the process 5. less data is required for handling positive planes