Pcb manufacturing and software

After the PCB has passed inspection — that is, neither the technician nor the AOI machine found any defects — it moves onto the last couple steps of PCB manufacture and production. The AOI step is crucial for the operation of the printed circuit board. Without it, boards that could have short circuits, not meet the design specifications or have extra copper that was not removed during etching could pass through the rest of the process.

AOI prevents defective boards from going on by serving as a quality checkpoint midway through the production process. Later, this process repeats for the outer layers after engineers finish imaging and etching them. At step six in the process, the PCB layers are all together, waiting to be laminated. The PCB laminating process is done in two steps: the lay-up step and the laminating step. The original piece of the substrate is also covered in a layer of thin copper foil that now contains the etchings for the copper traces.

The sandwiching of these layers is done using metal clamps on a special press table. Each layer fits onto the table using a specialized pin. A layer of the substrate is placed over the pre-impregnated resin, followed by a copper foil layer. The copper foil is in turn followed by more sheets of pre-impregnated resin, which are then finished off with a piece of and one last piece of copper known as a press plate.

Once the copper press plate is in place, the stack is ready to be pressed. The technician takes it over to a mechanical press and presses the layers down and together. If the layers are fixed properly, the PCB stack is taken to the next press, a laminating press. The laminating press uses a pair of heated plates to apply both heat and pressure to the stack of layers.

The technician needs to remove the top press plate and the pins from earlier, which then allows them to pull the actual PCB free. Before drilling, an X-ray machine is used to locate the drill spots.

When it comes time to drill these holes, a computer-guided drill is used to make the holes themselves, using the file from the Extended Gerber design as a guide. The plating process uses a chemical to fuse all of the different layers of the PCB together. After being cleaned thoroughly, the PCB is bathed in a series of chemicals. Part of this bathing process coats the panel in a micron-thick layer of copper, which is deposited over the top-most layer and into the holes that have just been drilled.

Bathing those holes in copper covers the walls of the previously drilled holes. However, this time the photoresist is only applied to the outside layer, since it still needs to be imaged. However, while the process is the same, the outer layers get a plating of tin to help guard the copper of the outside layer. When it comes time to etch the outside layer for the last time, the tin guard is used to help protect the copper during the etching process. Any unwanted copper is removed using the same copper solvent from earlier, with the tin protecting the valued copper of the etching area.

One of the main differences between the inner and outer layer etching covers the areas that need removal. While inner layers use dark ink for conductive areas and clear ink for non-conductive surfaces, these inks are reversed for the outer layers. Therefore, the non-conductive layers have dark ink covering them, and the copper has light ink. This light ink allows for the tin plating to cover the copper and protect it. Engineers remove unneeded copper and any remaining resist coating during etching, preparing the outer layer for AOI and solder masking.

As with the inner layer, the outer layer must also undergo automated optical inspection. This optical inspection ensures the layer meets the exact requirements of the design. Panels require a thorough cleaning before the solder mask application. Once clean, each panel has an ink epoxy and solder mask film covering the surface. Next, ultraviolet light strikes the boards to indicate where the solder mask needs removal. Once technicians take off the solder mask, the circuit board goes into an oven to cure the mask.

Because PCBs need to have information directly on the board, fabricators must print vital data on the surface of the board in a process referred to as silkscreen application or legend printing. This information includes the following:. After printing the above information onto the printed circuit boards, often with an inkjet printer, the PCBs have their surface finish applied. Then, they continue to the testing, cutting and inspection phases.

Finishing the PCB requires plating with conductive materials, such as the following :. However, applying such finishes creates an essential trait for the PCB. The finishes allow an assembler to mount electronic components. The metals also cover the copper to protect it from oxidation that can occur with exposure to air. After the PCB has been coated and cured if necessary , a technician performs a battery of electrical tests on the different areas of the PCB to ensure functionality.

The main tests that are performed are circuit continuity and isolation tests. While the electrical tests mainly exist to ensure functionality, they also work as a test of how well the initial PCB design stood up to the manufacturing process.

In addition to basic electrical reliability testing, there are other tests that can be used to determine if a PCB is functional. During this text, several spring fixtures are attached to the test points on the circuit board. The spring fixtures then subject the test points on the circuit board with up to g of pressure to see how well the PCB stands up to high-pressure contact at its test points. If the PCB has passed its electrical reliability testing — and any other testing the manufacturer chooses to implement — it can be moved on to the next step: route out and inspection.

Profiling requires fabrication engineers to identify the shape and size of the individually printed circuit boards cut from the construction board. This profiling step guides the routing out process by programming where the machine should create the scores on the construction board.

Routing out, or scoring, allows for easier separation of the boards. A router or CNC machine creates several small pieces along the edges of the board. These edges can let the board quickly break off without damage. However, some fabricators may choose to use a v-groove instead. This machine will create v-shaped cuts along the sides of the board. Both options for scoring the PCBs will allow the boards to separate cleanly without the boards cracking.

Aside from availability, the packaging of specific components chosen for a PCB assembly also affect their placement on the board. Little differences in packaging can make a big difference in the assembly process of the PCB. PCBflow makes sure that the component packaging is represented correctly in your design. Then it runs a BOM placement analysis to expose placement violations based on component geometry properties in comparison to the actual layout.

As a consequence, you no longer need to compile your own component library and manage and update it regularly — a costly and time consuming task. PCBflow provides you with built-in access to the Valor Parts Library , which has packaging data for over billion components! PCBflow will analyze for you the actual component placement using updated packaging data, prompting you to correct any violations before design handoff.

Join PCBflow to rethink and reshape design-to-manufacturing handoff. Altium Designer makes it easy to generate standardized deliverables for any manufacturer. Because the design engine is integrated throughout your circuit board design tools, you can rest assured your circuit board layout will obey DFM rules.

All the design features in Altium Designer are governed by a full set of design rules and constraints under your control so that you can make sure to design to the specific DFM guidelines that you need. Learn more about the unified design and manufacturing features in Altium Designer. Working in a rules-driven design environment is the easiest way to make sure you follow all the right PCB design and manufacturing guidelines. Altium Designer on Altium delivers an unprecedented amount of integration to the electronics industry until now relegated to the world of software development, allowing designers to work from home and reach unprecedented levels of efficiency.

We have only scratched the surface of what is possible to do with Altium Designer on Altium You can check the product page for a more in-depth feature description or one of the On-Demand Webinars. Zachariah Peterson has an extensive technical background in academia and industry.

He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics.

Mobile menu. Explore Products. Altium Community. About Author Zachariah Peterson has an extensive technical background in academia and industry. More content by Zachariah Peterson. Recent Articles. Do you know when a power plane resonance occurs in the PDN on a circuit board?