I. Common errors in schematic diagrams

(2) Component out of bounds: component is not created in the center of component library diagram paper.

(3) The created project file network table can only be partially loaded into PCB: Global was not selected when netlist was generated.

(4) Never use Annotate when using self-created multipart components.

Common errors in PCB

(1) When the network is loaded, it is reported that NODE is not found a. Components in the schematic diagram use packages that are not in the PCB library; B. Components in the schematic diagram use packages with different names in the PCB library; C. Components in schematic diagrams use packages with inconsistent PIN numbers in PCB library. For example, triode: the pin numbers in SCH are e,b,c, and 1,2,3 in PCB.

(2) Always cannot print to a page when printing

A. PCB library is not at origin when it is created; B. There are hidden characters outside the bounds of PCB board after moving and rotating components for many times. Select show all hidden characters, shrink the PCB, and then move the characters inside the boundary.

(3) DRC reporting network is divided into several parts:

This indicates that the network is not CONNECTED. Look at the report file and select CONNECTED COPPER to search.

If a more complex design, try not to use automatic wiring.

Common mistakes in PCB manufacturing process

(1) pad overlap a. Cause heavy hole, in the drilling because of multiple holes in a hole caused by drilling and hole damage.

B. In the multi-layer board, there are both connecting disks and isolation disks in the same position, and the board behaves as • isolation and connection error.

(2) The use of graphics layer is not standardized a. It violates the conventional design, such as component surface design in the Bottom layer, welding surface design in the TOP layer, causing misunderstanding.

B. There is a lot of design junk on each layer, such as broken lines, useless borders, annotations, etc.

(3) Unreasonable characters a. Characters cover SMD welds, which brings inconvenience to PCB on-off detection and component welding.

B. Characters are too small, resulting in screen printing difficulties, too large characters overlap each other, it is difficult to distinguish, general font > 40 mil.

(4) Single-sided pads set aperture a. Single-sided pads generally do not drill holes, the aperture should be designed to be zero, otherwise in the production of drilling data, the location of the hole coordinates. Special instructions should be given for drilling holes.

B. If the single-sided pad needs to be drilled, but the hole is not designed, the software will treat the pad as SMT pad when output electrical and formation data, and the inner layer will discard the isolation pad.

(5) Draw the pad with a filling block

In this way, although it can pass THE DRC inspection, it cannot directly generate solder resistance data during processing, and the pad is covered with solder resistance and cannot be welded.

(6) The electric stratum is designed with both heat sink plate and signal line, and the positive and negative images are designed together, causing errors.

(7) Large area grid spacing is too small

Grid line spacing < 0.3mm, in the process of PCB manufacturing, the graphic transfer process produces broken film after developing, resulting in wire breakage. Improve the processing difficulty.

(8) The graph is too close to the outer frame

The spacing should be more than 0.2mm at least (more than 0.35mm at V-cut), otherwise the copper foil will warp and solder resist will fall off during the appearance processing. Affect the appearance quality (including the inner copper skin of the multilayer panel).

(9) The outline frame design is not clear

Many layers are designed with frames, which do not coincide with each other, making it difficult for PCB manufacturers to determine which line should be formed. The standard frame should be designed in the mechanical layer or BOARD layer, and the internal hollowed out position should be clear.

(10) Uneven graphic design

When the graph electroplating, the current distribution is uneven, affecting the coating uniform, even cause warpage.

(11) Short shaped hole

Length/width of special-shaped hole should be > 2:1, width & gt; 1.0mm, otherwise CNC drilling machine can not process.

(12) No milling shape positioning hole is designed

Design at least 2 diameters in PCB if possible. 1.5mm positioning hole.

(13) The aperture is not clearly marked

A. Aperture should be marked in metric system as far as possible and increase by 0.05. B. As far as possible to merge the aperture into a reservoir area. C. Whether the tolerance of metallized holes and special holes (such as crimping holes) is clearly marked.

(14) The inner layer of the multilayer is unreasonable

A. The heat dissipation pad is placed on the isolation belt. It may fail to connect after drilling. B. The design of isolation belt is notched and easy to be misunderstood. C. The isolation belt is too narrow to accurately judge the network

(15) Design of buried blind orifice plate

The significance of design of buried blind hole plate: a. Increase the density of multilayer board by more than 30%, reduce the number of layers of multilayer board and reduce the size of b. Improved PCB performance, especially control of characteristic impedance (wire shortening, aperture reduction) c. Improve the freedom of PCB design d. reduce raw materials and costs, conducive to environmental protection. Others attribute the problems to work habits, which are often the problem of the person.

Lack of planning

As the saying goes, “If a man does not plan ahead, trouble will find him. “This certainly applies to PCB design as well. One of the many steps that make PCB design a success is choosing the right tool. Today’s PCB design engineers can find many powerful and easy-to-use EDA suites on the market. Each has its own unique capabilities, strengths and limitations. It should also be noted that no software is foolproof, so problems such as component packaging mismatches are bound to occur. It’s possible that no single tool will meet all your needs, but you still have to do your research beforehand and try to figure out what’s best for your needs. Some information on the Internet can help you get started quickly.

Poor communication

While the practice of outsourcing PCB design to other vendors is becoming more common and often very cost-effective, it may not be appropriate for complex PCB designs where performance and reliability are critical. As design complexity increases, face-to-face communication between engineers and PCB designers becomes important in order to ensure accurate component layout and wiring in real time. This face-to-face communication can help save costly rework later.

It is also important to invite PCB board manufacturers early in the design process. They can provide initial feedback on your design, and they can maximize efficiency based on their processes and procedures, which will save you considerable time and money in the long run. By letting them know your design goals and inviting them to participate in the early stages of PCB layout, you can avoid any potential problems before the product goes into production and shorten the time to market.

Failed to thoroughly test early prototypes

Prototype boards allow you to prove that your design is working to the original specifications. Prototype testing allows you to verify the functionality and quality of a PCB and its performance prior to mass production. Successful prototyping takes a lot of time and experience, but a strong test plan and a clear set of goals can shorten evaluation time and also reduce the likelihood of production-related errors. If any problems are found during prototype testing, a second test is performed on the reconfigured board. By including high risk factors early in the design process, you will benefit from multiple iterations of testing, identifying any potential problems early, mitigating risks, and ensuring that the plan is completed on schedule.

Use inefficient layout techniques or incorrect components

Smaller, faster devices allow PCB design engineers to lay out complex designs that use smaller components to reduce footprint and place them closer together. Using technologies such as embedded discrete devices on internal PCB layers, or ball Grid array (BGA) packages with less pin spacing, will help reduce board size, improve performance, and preserve space for rework if problems occur. When used with components with a high pin count and smaller spacing, it is important to choose the right board layout technique at design time to avoid problems later and minimize manufacturing costs. Also, be sure to carefully study the range and performance characteristics of the alternatives you plan to use, even those labeled as drop-in replacements. A small change in the characteristics of a replacement component can be enough to screw up the performance of an entire design.

Forget to back up important data for your work backup. Do I need to remind you? At the very least, you should back up your most important work and other hard-to-replace files. While most companies back up all of their data on a daily basis, some smaller companies may not do this, or even if you work from home. Today, it’s so easy and cheap to back up your data to the cloud that there’s no excuse not to back it up and store it in a secure location to protect it from theft, fire, and other local disasters.

Become a one-man island

While you may think your design is flawless and making mistakes is just not your style, many times your peers will see mistakes in your design that you didn’t notice. Sometimes, even if you know the intricate details of a design, people who have less exposure to it may be able to maintain a more objective attitude and provide valuable insights. Regular review of your design with your peers can help spot unforeseen problems and keep your plan on track to stay within budget. Sure, mistakes are inevitable, but if you learn from them, you can design a great product next time.