How to Reduce Costs in PCB Manufacturing
PCBs are a critical part of most electronic products. They carry electrical signals between components and provide a means of troubleshooting. They also protect components from damage and help them operate reliably.
Before manufacturing can begin, it is important to check the design for any errors or violations of design rules. This can be done using software tools.
Designing for manufacturing
The first step in reducing PCB manufacturing costs is to design the board for manufacturing. This involves examining the PCB’s component layout, size and placement. It pcb manufacturing also includes specifying any testing requirements and assembly drawings. The designer will examine the design for adherence to standards such as trace and hole widths, spacing, and layer alignment.
After the design is ready, it’s sent to a fabrication house. The fabricator will perform a second examination called a “Design for Manufacture” (DFM) check, which verifies that the PCB meets the minimum tolerances required to manufacture.
This stage is crucial for both the OEM and CM. The two entities must work together to ensure that the design is built to the exact specifications that were provided by the OEM. They should also agree on the correct file formats to prevent errors or lost information that may occur in cases where the files change formats.
Substrate preparation
Substrates are insulating materials that hold the components on a circuit board. They are typically fabricated from glass fiber and epoxy resin, although they can also be made of other materials. The choice of substrate material depends on its coefficient of thermal expansion (CTE), which measures how much the material expands or contracts with temperature changes. The best PCB substrates have low CTE values to reduce stress and strain on the board.
To prepare the substrate for bonding, it must be free of contamination and moisture. This is important to ensure the adhesive will adhere well. This process is known as cleaning the substrate. It can range from a simple brushing to a more extensive abrasive surface preparation.
The next step is to etch copper onto the surface of the substrate. This can be done with either a thin layer of copper foil or a full-on copper coating. The purpose of the copper is to carry electronic signals between the various components on the board, much like your nervous system carries messages from your brain to your muscles.
Printing the design
During this step, the PCB is printed with various text and markings. These are used to identify components and test points on the board. This also allows other manufacturers to locate the component locations during rework and assembly. It also helps to avoid mistakes by indicating which parts are active and which ones are not.
Different PCB software may call for a different Gerber format, but they all encode comprehensive vital information such as copper tracking layers, drill drawing, apertures and component notations. This stage is governed by standards and acceptability criteria of the IPC, which is an industry-wide quality standard for printed circuit boards.
It’s important to communicate clearly between the OEM and CM to ensure that the data is correctly converted into the physical structure of the PCB. It is also important to use the same file formats. This will prevent errors caused by translations between different formats.
Drilling the holes
Drilling is one of the most critical steps in PCB manufacturing and must be done correctly. This step creates the holes for component placement and vias, which are the pathways between layers. It is also the foundation for high-quality micromachining. The drilling process requires a high level of accuracy, and the implementation of the drill technology makes all the difference in the quality of the end product.
There are several different types of holes in a PCB, including plated through-holes (PTH) and non-plated through-holes (NPTH). The PCB design should indicate which type each hole is. These holes must be drilled to a specific tolerance, which is typically 0.005″ larger than the finished hole size to allow for plating.
The drilled holes are then cleaned and polished to remove any dust and PCB Manufacturing Supplier debris. This step is important because any contaminants can cause failure in the copper layer. The holes must also be sized properly to ensure good conductivity.
Layer alignment
The layers of a PCB are fused together during the lamination step. This process requires precise alignment and bonding. It also requires careful handling because of the complexity of the layers and their copper weight. To achieve this, metal clamps are used to secure the layers to a heavy steel table. During this phase, a layer of fiber glass pre-impregnated with epoxy resin is sandwiched between the inner and outer layers. This material is known as prepreg, and it is essential for multilayer boards.
The inner and outer layers are then lined up and a hole, called a registration hole, is punched through them using a computer-controlled machine. This ensures that the inner and outer layers are in perfect alignment.
You can use the Alignment submenu in the Object menu to align multiple layers in various ways. These commands move layers to line up with one another, or distribute them evenly along a horizontal or vertical axis. They are especially useful when you want to organize a jumble of layers into an even layout.
Optical inspection
Using automated optical inspection, also known as AOI, is the most reliable way to inspect a PCB. It’s a high-tech process that uses cool machines and computer programs to check for problems like missing or crooked parts. It’s faster and more accurate than manual inspection, which can be time-consuming and error-prone.
Optical inspection involves scanning the layers of the multi-layer circuit board before they’re laminated together. This helps to catch any errors, such as excess copper or missing pads, that may cause shorts and opens later on. It’s much easier to fix these errors at this stage than after the boards are assembled.
AOI uses different types of cameras to capture images. Some use streaming video while others take still images. Some AOI systems combine 2D and 3D images for better results. This is especially useful for smaller circuit boards because it gives more detailed information on the quality of solder joints and components.