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The Superconductive Circuit Board

How to Avoid PCB Board Delays in CAM

Posted by Paul Jackson on Tue, May 20, 2014 @ 12:21 PM

CAM (computer-aided manufacturing) is the art of translating a PCB board designer’s creative CAD (computer-aided design) output into information required in our manufacturing processes.

Omni PCB CAM delays Our processes require your computer generated files to be converted into phototooling films and drill/router files which will allow us, the printed circuit board manufacturing facility, to produce a custom PCB to your specifications.

Our challenge is we rarely know your design intent and in PCB manufacturing, as in life, Murphys Law applies. Your CAD data must completely and unambiguously specify the PCB you want; otherwise, we will make something else. Being human, mistakes happen. We would prefer not to multiply your one CAD mistake dozens or hundreds of times as real but quite unusable PCBs.

We hope you find this basic and downloadable PCB design checklist will save you time.

The starred items are most often inadvertently forgotten.

(Click checklist to download)

Omni Circuit Board Design Checklist

All Gerber files present:

  • Gerber files, that’s right we do receive orders missing these
  • Aperture data preferably embedded within extended Gerber format files (RS274X) which provides the shape and the size for all of the features within the printed circuit board.
  • Drilling: Both the NC drill files which provide the physical location of the holes and the Drill Tool List which provides the tool sizes. The information may be separated or combined into one file.
  • Mechanical layer which provides the outside profile and dimensions of your PCB board. (Warning - Rant) Please give us clean unambiguous outlines. It amazes us how many designers, even with CAD software, cannot join two line segments together to form a simple corner (okay that feels better now).

Design Checks:

  • Avoid cut metal at routed or v-scored edge. It’s nasty
  • Overlapping drill locations; they cause broken drill bits
  • Over-tolerancing. Visit our site for a complete list of design tolerance guidelines specifically:
    • Space and Copper Trace widths
    • Annular ring sizes
    • Drill sizes

Documentation

  • Readme file: Containing information about:
    - Cutouts - Board thickness - Panelization Requirements
    - Plated/non-plated through holes - Dielectric Material - Solder mask color
    - Max radii of inside routed corners - Finished Cu weights - Silkscreen color
    - Surface finishes - Finished hole sizes - Any special requirements
    An example of a PCB Readme file can be found here.
  • Part number and revision discrepancies. Any discrepancy between the part number or revision on the order, file names or physically on the circuit board will bring the process to a grinding halt.
  • Inner layers of Multi-layer designs need to have the layer order specified and each layer must be unambiguously identified.

It may help to think of the CAM department as the gatekeeper to manufacturing.

No design hits the shop floor until it meets with their approval. You also need to know if a problem does arise on the shop floor, the reaction can be blood curdling. Checking off these basic points will not only help ensure your PCB board design is not delayed, you may well be helping our CAM group reach retirement age with all of their faculties intact.

Are your files ready? Send them to us now and we'll send you a quote within one working day.

Tags: printed circuit board design, printed circuit board manufacturing, pcb board design, PCB drilling, PCB manufacturing

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Omni Circuit Boards is an e-sensitive manufacturer of Printed Circuit Boards.

Omni Circuit Boards has been in the printed circuit board fabrication business since 1985. It has been our goal to be as environmentally conscientious as possible.

We are committed to keeping our customers and the future of our children front of mind.

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