CAD and CAM work in PCB design

A good introduction about CAD and CAM work.

A. Enter the CAM system used by Gerber Data, and the apertures and shapes must be defined.Currently, there are many PCB CAM systems acceptable to ipc-350 format.Part CAM system can generate NC Routing, but general PCB Layout design software does not produce this file.There are some professional software or independent or coordinated NC Router, which can set parameter direct output program.

The Shapes of Shapes are round, square and long, and also have complex Shapes such as the inner layer of thermal pad.When designing, the connection between Aperture code and shapes must be defined first, otherwise the series of designs can not be carried out.

B. Check list at design time

According to the check list review, the yield and cost estimates of the production number may be known.

C. Working Panel layout considerations:

The PCB Layout engineer will do some auxiliary markers to help remind or pay attention to certain matters when designing, so you must remove them before entering the Layout.The following table lists several projects and their impact.

- the size selection of the layout will affect the interest rate of the material.Because the base board is the main raw material cost (the best setting, can reduce the waste of the board);Properly typesetting can increase productivity and reduce bad rate.

Some factories believe that certain work sizes can meet maximum productivity, but the cost of raw materials increases a lot. Here are some considerations:

General production costs, direct and indirect materials account for about 30 ~ 60%, the total cost includes the base board, film, copper foil, prevent welding, dry film, bit, heavy metals (copper, others, lead, gold), consumption of chemical products, etc.The consumption of these raw materials is related to the proper size of the layout.Most electronics factories make a series of designs when they run the Layout, so that the assembly can have the highest productivity.Therefore, the former designers of pcb factory should communicate closely with customers so that the size of the sheet Layout can have the best utilization rate when composing the work PANEL.To calculate the most appropriate typography, consider the following factors.

1. The minimum number of knives and the maximum utilization rate (the cutting mode and the edge treatment should be considered).

2. The size of copper foil, film and dry film should be matched with the size of work PANEL to avoid waste.

3. The minimum size of the piece, as well as the minimum size of the tool or counterpoint system.

4. Maximum size limit or effective workspace size for each process.

5. Different product structure have different production process, and different layout constraints, for example, gold finger board, its layout spacing should be larger and direction, the test fixture or test sequence is different also.Great size, can accord with greater productivity, but the raw material cost increase a lot, and equipment also need to improve process capability, how to achieve a balance, design criteria and engineer experience is very important.

- in the process of setting up the working Panel, the following items should be considered in order to make the process smoother and the list layout considerations.