Wednesday, June 30, 2010

FAB 3000: Use Import Matrix to simplify Gerber Import and Layer configuration

The FAB 3000 Import Matrix File permits external tools (like PCB Layout software) to predefine layers and jobs for intelligent loading into FAB 3000 for instant Gerber Viewing & Verification. This prevents the PCB designers from having to perform the monotonous steps of loading Gerber & Drill files, assigning layer colors, assigning layer types, defining layer stack ups, defining blind/buried drill layers (if required), etc. The Import Matrix file allows PCB designers to easily use Gerber/CAM software for its primary purpose... to quickly verify their gerbers & drills are ready for manufacturing.

I will provide links containing the basic elements of the FAB 3000 Import Matrix File along with all available options and descriptions.

Matrix Rules:

RULE #1: LAYER arrays are Always defined first.
RULE #2: JOB arrays are defined after LAYER arrays
RULE #3: PANEL arrays are defined Last

Sample Matrix Files:

Matrix File Definition:

Fields in the DFMCHECKER array:

Sample C++ Code for calling FAB 3000 with Import Matrix File:

Monday, June 28, 2010

Polygon De-Embedding Basics

CAD geometries can be complex to visualize because most are drawn with 'zero width' lines. The polygon-inside-of-polygon is often the hardest mistake to catch and it’s almost impossible to visually determine the polarity for each. A mask operator can sometimes take hours attempting to repair or redraw the data so that re-entrant polygons are created with voids or has to break up the polygons into slices. In any case, the production of the mask is delayed and it is possible to introduce additional mistakes while performing the editing.

Polygon De-Embedding
automatically solves the polygon-inside-of-polygon problem (see below).

Numerical Innovations has developed several products that include Polygon De-Embedding feature: ACE 3000, FAB 3000, and Visual Chip 3000. To use Polygon De-Embedding during DXF import, select layer option "De-Embed" for each layers you wish to perform De-Embedding. To may also select objects, and go to menu: Edit | De-Embed...

Friday, June 25, 2010

Introducing FAB 3000 DFM

"World's Best Gerber Viewing and DFM Solution."

While most PCB Layout tools are very good at performing DRC (Design rules check), they rarely capture many common DFM (design for manufacturing) problems that are hidden in the physical artwork (i.e. gerber, drill files). It's the artwork which is ultimately used to manufacture your boards (not the PCB Layout database) and any hidden problems in your artwork WILL AFFECT the manufacturability and yield of your boards. This is why using a Gerber Viewer has been so popular with PCB designers, but unless you have eyes like a hawk, simply staring at gerber files (containing hundreds of signals & thru holes) inside a free viewer is just an invitation for mistakes. FAB 3000 DFM is your protection against these common DFM problems and mistakes. For more information, please view the following link:

Note: FAB 3000 DFM is basically a "beefed-up" Free Gerber Viewer plus DFM engine used by engineers who want to do more than view: such as quickly perform manufacturing checks on the Gerbers, compare designs, load ODB++, etc. FAB 3000 DFM also has a direct link with EasyGerb and ACE 3000, so you can instantly view your results.

Note: FAB 3000 SuperView has been renamed to FAB 3000 DFM (on June 28th, 2010).

What is Gerber data?

For the past 30 years, Gerber data has been the de-facto standard file format used to manufacture all PCB’s (printed circuit boards). The Gerber format itself is simply an ASCII text file containing X,Y coordinates, and shapes (i.e apertures/dcodes). There are essientially 4 flavors of Gerber data: RS-274D, RS-274X, Fire9000, and BarcoDPF.

(Sample screen capture of Gerber data inside FAB 3000.)

Gerber data is a simple, generic means of transferring printed circuit board information to a wide variety of devices that convert the electronic PCB data to artwork produced by a photoplotter. Virtually every PCB CAD system generates Gerber data because all photoplotters read it. It is a file structure consisting of X,Y coordinates supplemented by commands that define where the PCB image starts, what shape it will take, and where it ends. In addition to the coordinates, Gerber data contains aperture information, which defines the shapes and sizes of lines, holes, and other features.

Gerber RS-274X: Extended Gerber Format, which is also called RS-274X, provides enhancements that handle polygon fill codes, positive/negative image compositing, and custom apertures, and other features. RS-274X also encapsulates the aperture list in the header of the Gerber data file and therefore allows files to pass from one system to another without the need to re-input the aperture table. RS-274X produces a variety of Gerber data called X data.

The Problem - Gerber files can be Difficult to Handle: Gerber data is unique in the fact that each file usually represents a single layer, something different from most other EDA formats that may contain multiple layers & designs/blocks all inside a single file. Many Gerber files are not written to specification; Thus many "unwritten rules" must be made to properly load in these files to the authors intention. For more information about these problems read the article: Don't trust your Gerbers.

Here is a list of some common difficulties found inside Gerber files: Transcoding of apertures - when multiple gerber files define the same aperture dcode, but require different shapes, Handle complex custom aperture definitions. Handle 'user-defined' custom aperture macros ($). Circular Interpolation: Arcs (G75), & Quadrant Arcs(G74) Poly-Fill routines(G36,G37) Support composite merging(LPD/LPC) Photo Expose mode (G55) Step/repeat codes(SR) Offsets(OF),Units(G70,G71),Mirror(MI) Zero Suppression with leading or trailing zeros. Format type: Incremental(G91)

Choosing the right Gerber Editor/Viewer. Gerber data may seem like a simple format to comprehend, however "in the real world" almost every PCB layout software tool outputs gerber data with their own unique set of rules (in many cases these gerber files are invalid). For success in manufacturing, the Gerber tool must interpret what the "PCB layout software" meant and correctly display all geometries.

Also, many gerber software tools found on the internet are not complete, and have a hard time loading & viewing complex gerber files properly; some common mistakes involve the display of custom flashes, composite layers, large polygons, step/repeat, rounded/square paths, and more.

It takes thousands of hours testing, refining, & perfecting the gerber import process to ensure that a gerber software tool will successfully load all types of gerber data files (no matter where they originated or what tool has generated them). Make sure to choose a software vendor with an established gerber viewer, who constantly makes updates to their gerber software (because the gerber format is always evolving). Remember a free Gerber Viewers is not always free, and one mistake can cost thousands of dollars. If you work with gerber data you are better served investing in a professional gerber solution.