How to design shaped pcb 2

- Jun 28, 2017-

If you return a rented car, you may see that the attendant reads the car information with a handheld scanner and then performs wireless communication with the office. The device also connects a thermal printer for instant receipt printing. In fact, all of these devices use a rigid / flexible circuit board (Figure 4), where the traditional PCB circuit board and flexible printed circuit interconnection, so that can be folded into small space.

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The question is, "How do I import the defined mechanical engineering specifications into the PCB design tool?" Reusing the data in mechanical drawings eliminates duplication and, more importantly, eliminates human error.


    We can solve this problem by importing all the information into the PCB Layout software using the DXF, IDF, or ProSTEP format. This can save a lot of time, but also to eliminate possible human error. Next, we will understand these formats one by one.


    Graphics Interchange Format - DXF


    DXF is one of the oldest and most widely used formats that exchange data electronically between the mechanical and PCB design domains. AutoCAD was developed in the early 1980s. This format is mainly used for two-dimensional data exchange. Most PCB tool vendors support this format, and it does simplify data exchange. DXF import / export requires additional functionality to control the layers, different entities, and units that will be used during the exchange process. Figure 5 is the use of Mentor Graphics PADS tool to DXF format into a very complex circuit board shape of an example.

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A few years ago, 3D functionality began to appear in the PCB tool, and there was a need for a format that could transfer three-dimensional data between the machine and the PCB tool. As a result, Mentor Graphics developed the IDF format, which was then widely used to transfer board and component information between PCBs and mechanical tools.


     Although the DXF format contains the board size and thickness, the IDF format uses the X and Y positions of the component, the component bit number, and the Z-axis height of the component. This format greatly improves the functionality of visualizing PCBs in 3D views. Additional information about the prohibition area, such as the height limit of the top and bottom of the board, may also be included in the IDF file.


     The system needs to be able to control what will be included in the IDF file in a manner similar to the DXF parameter setting, as shown in Figure 6. If some components do not have a high degree of information, the IDF export can add missing information during the creation process.

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Another advantage of the IDF interface is that either party can move the component to a new location or change the board shape, and then create a different IDF file. The drawback of this approach is that you need to re-import the entire file that represents the board and component changes, and in some cases, the file size may take a long time. In addition, it is difficult to determine which changes have been made through the new IDF file, especially on larger boards. IDF users can eventually create custom scripts to determine these changes.

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