Therefore, I asked our "adapters" a question about what to look for when preparing for the production of the board.
1. Analyze the technical requirements specified in the design documentation.
2. Conduct DFM analysis of the board - that is, design the printed circuit board in such a way that in the future, during production and installation, there will be as few problems as possible. Moreover, here it is necessary to check not only the standard CAD functions, but also taking into account our own work experience.
3. Check the integrity of the circuits during and after processing the file. Ideally, you should have a project source file, not a bundle of gerber files.
4. If the board is multilayer, then make its stack - the order of the conductive layers and dielectric layers. You should not completely trust the designer who designed the board, because, as practice shows, everyone can make a mistake, the probability is high and is more than 30%. The following mistakes are often encountered: rare materials are used in projects, which would be more expedient to replace; there is no information about the technological features of the assembly and the symmetry of the board in the section.
5. Check the layers of the protective mask to avoid problems when installing products.
6. Be sure to check and work through the silkscreen layers. Otherwise, there may be mirrored or unreadable text on the finished board, which may creep onto the mounting holes or elements of the circuit drawing required for subsequent mounting. Many standard fonts have peculiarities - hieroglyphs or other designations appear for Russian text.
7. Check the specification, assembly drawing and board footprints for compliance with the products in which these boards will be mounted.
8. Prepare the layers for making SMD metal stencils.
9. Generate programs for the equipment that will be used in the production of printed circuit boards and assembly of products, and export them.
In addition to the points listed above for preparing the circuit for the production of a board, the process of preliminary evaluation of projects is now gaining popularity. In this case, the developers, together with the manufacturers, perform the technological debugging of the printed circuit board and, as a result, the finished project has practically no errors.
What you should pay attention to during the preliminary check:
1. The presence of blind and hidden holes. Sometimes, when analyzing a project, we realize that hidden or blind holes are needed. But more often than not, you can do without them and lay the connections of the layers into the through holes.
2. Properties of certain holes. It often happens that when importing gerbera files and drilling files, all mounting holes have metallization, and the file processing system is guided by the layers in which these holes are located.
3. Symmetry of the multilayer printed circuit board. It is very important to ensure that the multilayer PCB has a symmetrical assembly around the center.
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4. Location of vias. How well these holes are located will determine the quality of further soldering. We recommend placing vias no closer than 0.3 mm from the element pads.
5. Fiducial marks. The use of such signs in projects is important for automating the process of surface mounting of a printed circuit board. Fiducials are used to improve the accuracy of the alignment of the component with the pads and mounting base.
6. Unprocessed marking layers in projects. Along with the imposition of text on the places where the soldering should be, it is often found that the item designators are located on the vias. If the vias are relatively large, the text becomes unreadable. Therefore, we advise you to pay attention to the location of the labels, their properties and the uniform direction of the text.
So, before starting the manufacture of a printed circuit board, pay special attention to the preparation process and double-check the possible places where an error may occur later, which will entail a rework of the project.