（1） , check the user’s file
First of all, routine inspection should be carried out for the documents brought by users
1. Check whether the disk file is in good condition;
2. Check whether the file contains *, if there is *, you must kill *;
3. If it is a Gerber file, check whether there is a D code table or contains D code.
（2） Check whether the design conforms to the process level of our factory
1. Check whether the various distances designed in the customer’s documents are in line with the factory’s process: the spacing between lines, the spacing between lines and pads, the spacing between pads and pads. The above spacing should be greater than the minimum distance that can be achieved by our production process.
2. Check the width of the conductor, which shall be greater than the minimum that can be achieved by the production process of the factory
3. Check the size of the through hole to ensure the minimum diameter of the production process.
4. Check the size of the pad and its internal diameter to ensure that the edge of the pad after drilling has a certain width.
（3） , determine process requirements
Various process parameters are determined according to customer requirements.
1. According to the different requirements of the post process, determine whether the photo negative (commonly known as film) is mirror image. Principle of film mirror image: the film surface (i.e., glue surface) is pasted on the film surface to reduce the error. The decisive factor of negative image: technology. If it is screen printing process or dry film process, the film surface of the negative film is attached to the copper surface of the substrate. In case of exposure with diazo film, the mirror image should be the film surface of the negative film without sticking to the copper surface of the substrate because the diazo film is mirror image when copying. If the photolithography is a unit negative, rather than assembling on a photo negative, an additional image should be added.
2. Determine the parameters of solder mask expansion.
① Do not expose the wire next to the pad.
② Small can not cover the pad.
Due to the error in operation, the solder mask may have deviation to the circuit. If the solder mask is too small, the result of deviation may cover up the pad edge. Therefore, the resistance welding should be larger. However, if the solder mask is enlarged too much, the adjacent wires may be exposed due to the deviation.
It can be seen from the above requirements that the determinants of solder mask expansion are as follows:
① The deviation value of position and figure of resistance welding process in our factory.
Due to the difference of various welding resistance values, the corresponding process deviation is also increased
Different. The expanded value of resistance welding with large deviation should be selected larger.
② The board has large wire density, and the distance between pad and wire is small, and the expansion value of resistance welding should be smaller
If the density of sub conductor is small, the expansion value of solder resistance can be selected larger.
3. Determine whether to process the line according to whether there is a printed plug (commonly known as gold finger) on the board.
4. Determine whether to add conductive frame for electroplating according to the requirements of electroplating process.
5. Determine whether to add conductive process line according to the requirements of hot air leveling (commonly known as tin spraying).
6. Determine whether to add pad center hole according to drilling process.
7. Determine whether to add process positioning hole according to the subsequent process.
8. According to the shape of the board, determine whether to add the shape angle line.
9. When the user requires high line width accuracy for high-precision boards, it is necessary to determine whether to carry out line width correction according to the production level of the factory, so as to adjust the influence of side corrosion.
（4） , CAD file converted to Gerber file
In order to manage cam process in a unified way, all CAD files should be converted to Gerber and equivalent d-code table.
In the conversion process, attention should be paid to the required process parameters, because some requirements are to be completed in the conversion.
In addition to smart work and Tango software, all CAD software can be converted to Gerber. The above two kinds of software can also be converted to Protel format and then to Gerber through tool software
（5） , cam processing
According to the process to carry out a variety of processing.
Special attention should be paid to whether there are any places with too small space in the user file, which must be handled accordingly
（6） , photo output
After cam processing, the file can be photo output.
The work of plate splicing can be done in cam or at the time of output.
A good photo drawing system has certain cam functions, some process processing must be carried out on photo plotter, such as line width correction.
（7） , darkroom treatment
The photo negative needs to be developed and fixed before it can be used in subsequent processes. In darkroom processing, the following links should be strictly controlled:
Development time: affects the optical density (commonly known as blackness) and contrast of the production plate. The time is short, the optical density and contrast are not enough; if the time is too long, the fog will aggravate.
Fixing time: if the fixing time is not enough, the background color of the production plate is not transparent enough.
Time of non washing: if the washing time is not enough, the production plate will turn yellow easily.
Special attention: do not scratch the film.