Thursday, April 07, 2005

How PCB is manufactured

Printed Circuit Board (PCB) are manufactured through a series of phot imaging and etching processes. For a start we need a schematic of the circuit to be created in a CAD software, from this schematic a "Gerber Data file is created and then is converted via computer aided manufacturing software (CAM) to form the basic layout of the Printed Circuit board itself.

CAM software will generate the artwork with the aid of a plotting machine, these artwork will be use in the PCB manufacturing process.

Circuit board materials like FR4, Polymide, Getek etc comes in various sizes which have to be pre cut into specific panel dimensions depending of the amount of boards to be layout on the panels. For multilayer boards, each layer is make just like making multilayer cakes, layer by layer and finally bake in an oven.

The panels are first coated with light sensitive film, and the images from the artwork are printed on the coated panels. Through a process of etching the unwanted areas of the panel copper are removed, leaving only the circuit traces. All the other layers are process in the same manner.

The etched layers are then laminated together by pressing them with thin sheets of resin coated fiberglass under high pressure and high temperature. When the board cools the layer are bonded together. Holes are drilled using the drill data file from the Gerber output. Through hole plating is then performed to connect the various layer of each hole to make electrical contacts.

The next step is to provide a coating of solder mask to the panels in order to protect the circuitry from receiving any solder during assembly. This process covers the circuitry to leaves the holes and/ or surface mount tabs (smt) exposed so they can receive solder during assembly.

Final processes include fabrication of each panel where each board is cutout of its panel and; electrical test, where each board is individually tested for opens and shorts, Before shipment to the customer, each part is inspected for workmanship and quality.

1 comment:

alansaki said...

You share such a great info related to pcb manufacturing as a pcb manufacture this post is very informative for me.
circuit board