CIRCUIT BOARDS: HOW DO THEY WORK?

PCB manufacturing is the procedure used to create the boards that serve as the base for the printed circuit board assembly.

Choose your PCB fabrication company with care because even the smallest of mistakes could cause damage to the entire board which renders the finished product unusable. Communication between the design team and the manufacturer is essential, particularly since manufacturing has gone overseas.

In this article we look at the essential information you need regarding this PCB fabricating process which includes the pre-processing, PCB fabrication in full and the considerations to take while choosing the best PCB fabrication firm.

WHAT IS THE DIFFERENCE BETWEEN PCB FABRICATION AND PCB ASSEMBLY PROCESS?

PCB manufacturing along with PCB assembly comprise two separate components in PCB manufacturing. PCB fabrication process.

PCB manufacturing is the method of transcribing a circuit board’s design onto the physical design that makes up the panel. Contrastingly, PCB assembly is the procedure of putting components on the board in order to make it functional. PCB fabrication is often compared to the roads, pathways and zoning of a city. PCB assembly is actually the structure that allow the printed circuit board work. Information about PCB assembly can be located here.

STEPS BEFORE STARTING THE PCB FABRICATION PROCESS

The process of creating the printed circuit boards is about the details. The initial design should be finished, since any component update that isn’t synchronized could result in a flawed board design. This can include:

• An entire engineering review of circuits
• Synchronized layout and schematic databases
• Full circuit simulation and signal integrity and analysis of power integrity
• Examined PCB designs and limitations
• The bill of materials and the design for manufacturing regulations are examined

THE PCB FABRICATION PROCESS

Laser Direct Imaging and Develop/Etch/Strip Process

Before beginning work on the multi-layer printed circuit board Laser direct imaging (LDI) is applied to create areas that are later to become pads, traces and ground metal of the printed circuit board.

1. A dry film is bonded to the copper laminate.
2. The laser direct image exposes components of the board light in the form of an PCB design.
3. Any un-exposed areas on the surface will begin to develop away, leaving the remainder of the film to act as an the etch barrier
4. The remainder of the film acts as an etching barrier that will be removed from copper and reassembled to form the copper circuit.

Following this the automated optical inspection examines the layers for any defects prior to when they are laminated. Any errors, including openings or shorts, can be rectified at this point.

Oxide and Lamination

When all the layers have been removed, a chemical treatment known as oxide is applied to the layers inside printed circuit boards to increase the strength of the bond. Then, the layers of copper foil and prepreg are joined using pressure and heat. Prepreg is a material made of fiberglass made up of an epoxy resin, which melts due to the pressure and heat generated by lamination, which binds the layers to form an “PCB sandwich”.

It is essential to pay attention to ensure that the alignment of circuitry between layers is ensured.