BBG Tech Tip #11

Creating a Complete Tooling Package

The submittal of a complete tooling package ensures that your PCB supplier will provide you with quality product that is shipped on time.

A tooling package is made up of the following:

Company Specifications: It is importaint that your new supplier receives a copy of your company's approved workmanship standard or specification with the first order placed. More importantly, make sure that your vendor receives subsequent revisions to ensure they are always current with your standards.

Fabrication Notes: Material type to be used, the finished thickness, layer count, metal finish, soldermask color, legend and route specifications among other items are mentioned in this list that describes how the PCB is supposed to be manufactured.

Gerber Data: A Gerber is a type of electronic data that consists of graphic commands, usually describing how to draw a picture of a circuit. Intended for directing a photoplotter, it is the most common format for data transfer from PCB CAD systems to the manufacturing process. Gerber data is officially designated as RS-274-D (without embedded aperture codes) and RS-272-X (with embedded aperture codes).

Aperture List: A list of codes used to plot the Gerber data with each having a designation that allows for shapes of different sizes like a square, rectangle, flash, draw, etc. to be drawn.

Drill File and Location: A list of drill sizes and coordinates for the drilling of the PCB.

Read Me File: A text file detailing your company name, contact information, engineer or designer's name, name of the Gerber file, the aperture list and drill file to be used in the manufacture of the particular part number. Any information pertaining to the particular part number may be referenced in this message as well.
Once your supplier's engineering department receives the tooling package, the assigned engineer will begin processing the order. Design factors and the manufacturing capability of the PCB supplier are considered when the job traveler is prepared. The traveler is a procedural sheet specific to that particular part number and details what procedure a technician should follow in each individual operation. The traveler begins with the cutting of material and documents all processes up to detailing the way the order is to be shipped. It is a written procedure intended to ensure each operation is performed exactly the same way each and every time.

The engineering department is also responsible for the programming of the electrical test fixture and its manufacture.

It is the responsibility of the engineer to communicate with the production department to make sure that a quality product will ship on time. There are many areas not metioned above that must be reviewed by the engineering department. The more time spent in up-front engineering the better the order will run through the process with less chance of failure. Don't be surprised or upset when your supplier's engineer asks questions to clarify what is desired. The number of questions asked is proportional to the quality received.

Research for the above information may be from, but is not limited to, IPC reference manuals, the PCB Handbook, the Bare Board PWB Design Manual and consultation with industry professionals. Please consult a process engineer familiar with your company's PCB assembly process before making any procedure changes.