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Basic Steps Of PCB Fabrication

PCB fabrication consists of several steps. Once you have created the board design, you may go to us to start the fabrication process.

To get started, you may obtain a free quote by filling out our online form or by sending us the following details:

• BOM (Bill of Materials)

• Gerber Files/Assembly Drawing

• Pick and Place Data

• Lead Time and Quantity Desired

PCBWe will contact you shortly regarding your quote. We can typically send you a TurnKey quote within the day (if we receive your request before 11 a.m. CST). Our Full TurnKey feature is the fastest way to get a quote and we are the first in the industry to offer this to our customers. With our online quote system, you can receive your quote within a few minutes of uploading your BOM.

If you don’t have an accomplished board design yet, here are some steps you can follow to create one before proceeding to PCB fabrication.

You can apply these steps if you are using PCB software in creating your design:

1. Capture the schematic diagram through an EDA (electronic design automation) tool.

2. Determine the template and dimensions of the board based on the required case and circuitry of the board.

3. Identify the locations of the heat sinks and other components.

4. Decide on the board’s layer stack. This ranges from 1-10 layers depending on the complexity of the project. You also need to decide on the power planes and grounds. Power planes are the equivalent of ground planes and act as AC signal grounds while supplying DC power to each of the circuit that is mounted on the board.

Printed circuit boards

5. Line impedance is established using the thickness of the routing copper and dielectric layer, as well as the width of the trace. The separation of the traces is also considered in case there is a discrepancy with the signals.

6. Place the electronic parts. Geometry and thermal factors are considered to place the components in appropriate locations.

7. Signal traces are then routed, and the software will usually generate ground plane and power connections and clearances automatically.

8. Gerber files are created, so you can use them in manufacturing.

The Fabrication Process
Following are the basic steps of PCB fabrication:
PCB CAM (Computer-Aided Manufacturing)

The manufacturing process begins by generating data from the software, including IPC-D-356 netlist Gerber drill files and layer images, and component information. The Gerber files are not directly used on the fabrication equipment, but are always scanned into the CAM, which then performs these functions:

• Input the fabrication data

• Verify the data

• Check for any distortion in the process and compensate it

• Group PCBs onto larger boards (panelization)

• Apply digital tools, including drill files, electrical test files, legend image, data for automated optical inspection, solder resist image and copper patterns.

Panelization

Panelization is a process wherein PCBs are grouped together, so you can place them on a larger board, which is the panel. There are two main types of panel, namely, assembly panels (also referred to as “arrays”) and bare board panels. The panel usually consists of a single board design, but in some occasions, it is possible to mix multiple designs on the same panel.

Eventually, the panel is split into individual boards – a process called “depanelling.” The separation of individual boards is done by using routing or drilling perforations along the borders of each circuit.

Copper Patterning

Pcb fabricationThe pattern in the CAM system is replicated on a mask on the copper-foil PCB layers. It is followed by the etching process that removes unnecessary copper on the board. This step is important to create faultless boards during the entire PCB fabrication process. Copper patterning methods include:

• Silkscreen printing – protective masks are created by using etch-resistant inks.

• Photoengraving – the coating of UV-sensitive photo resist is removed using a developer and photo mask. This process creates a photo resist mask.

• Laser resist vaporization – black paint is sprayed onto the copper-clad laminate. The laser scans the PCB and vaporizes the paint on parts where a resist is not
necessary.

• PCB milling – the copper foil is milled away from the substrate using a 2 or 3-axis mechanical milling tool. A board milling machinery (also called PCB Prototyper) works in the same way as a plotter. The host software controls the positioning of the mill head and sends commands to the milling machine.

Choosing a patterning method depends on the quantity of boards that you wish to produce during PCB fabrication. Silkscreen printing and photoengraving are usually used for large volumes, while laser resist vaporization and PCB milling are used for smaller production of PCBs.

PCB fabrication is a multi-step process that is mostly carried by machines. PCB Fabrication are prepared and ready to deliver the finest quality items that our clients have generally expected.