PCB Fabrication Enhancements

Support for ODB++ Files

The PCB Fabrication manufacturing process model now can analyze printed circuit board designs provided as ODB++ files.

In this release, aPriori Professional can analyze ECAD (Electronic Computer-Aided Design) models that have been exported in accordance with ether version 7 or version 8 of the open database ODB++ specification. aPriori Professional supports ODB++ files that are in *.zip, *.tgz and *.tar file formats.

To open an ODB++ file, use the Open CAD File dialog, just as you would for a Gerber file. Once you have loaded a supported ODB++ file, aPriori Professional extracts the same Geometric Cost Drivers (GCDs) and GCD properties from the ODB++ file as it does from Gerber files. Then, it uses the extracted data to simulate the manufacturing approach, cycle time, and cost.

There are several advantages to using ODB++ files, which is a more structured and standardized file format than the Gerber file format. aPriori Professional does not require an XSLT (Extensible Stylesheet Language Transformation) mapping file to interpret ODB++ files and, therefore, generally extracts geometry for ODB++ files faster than it does for Gerber files. The structured data also enables aPriori Professional to extract the values of board thickness and copper thickness per layer more reliably, resulting in less user input for the material stock selection.

The baseline aPriori Professional manufacturing process model supports standard copper weights of 0.5, 1, 1.5 and 2 oz. However, as is common in Gerber files and expected in the manufacturing process modeling, ODB++, copper layers are specified by thickness rather than by weight. To convert copper thicknesses (in um) to copper weight (in oz), aPriori Professional uses copperThicknessOunceToMicrons, a new site variable. By default, copperThicknessOunceToMicrons is set to 35.00, indicating 35um copper thickness is equivalent to 1 oz. You can adjust the value of this site variable to configure the conversion between um to oz, so that the value of a Layer GCD's Material Thickness property is set to the expected value.

A new cost model variable copperLayerThicknessSnapTolerance provides an allowable tolerance range (+/- 0.05 oz by default) that is applied when aPriori Professional selects a copper material from the Material Database in the Digital Factory. This variable enables aPriori Professional to select an appropriate copper weight from the digital factory despite small rounding errors that can occur when aPriori Professional reads ODB++ files and converts copper layer thickness values to copper weights.

For example, if the computed copper weight for a layer may be 0.98 oz rather than the expected value of 1 oz. If an exact match is not found for the extracted Layer GCD thickness, then a material within the tolerance range set by copperLayerThicknessSnapTolerance is considered.

If an ODB++ file does not contain the external outline of the PCB, aPriori Professional determines a rectangular bounding box that contains all holes in the board and uses this as the board outline. aPriori Professional applies the same method to Gerber files that do not contain PCB external outlines.

More robust interpretation for Altium Gerber files

aPriori Professional can now determine the number of copper layers in a PCB even when the data is missing from the Altium Gerber file export.

In previous releases, when an Altium Gerber file export did not define the Layer_Physical_Order property, aPriori Professional could not determine the number and order of copper layers for the PCB. Now, if the Layer_Physical_Order property is missing, aPriori Professional determines the number of copper layers by leveraging unique file extensions that Altium creates for each layer.

To use this enhancement, you must load an updated version of the PCB XSLT mapping file into your deployment. Please contact aPriori Support to obtain an updated XSLT mapping file and for assistance in loading it.