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PCB Tech
PCB circuit board light painting (CAM) operation process
PCB Tech
PCB circuit board light painting (CAM) operation process

PCB circuit board light painting (CAM) operation process

2021-11-07
View:41
Author:Downs

Check user's files

The files brought by the user must first be routinely checked:

1. Check whether the disk file is intact;

2. Check whether the file contains a virus, if there is a virus, you must first kill the virus;

3. If it is a Gerber file, check whether there is a D code table or contains D code.

Check whether the design meets the factory's technological level

1. Check whether the various spacings designed in the customer files conform to the factory's process: the spacing between the lines, the spacing between the lines and the pads, the spacing between the PCB pads and the pads. The above various spacings should be greater than what our production process can achieve

Minimum spacing.

2. Check the width of the wire. The width of the wire should be greater than the minimum line width that can be achieved by the factory's production process.

3. Check the size of the via hole to ensure the smallest diameter of the factory's production process.

pcb board

4. Check the size of the pad and its internal aperture to ensure that the edge of the pad after drilling has a certain width.

Determine PCB process requirements

Various process parameters are determined according to user requirements.

Process requirements:

1. For the different requirements of the subsequent process, determine whether the light painting film (commonly known as film) is mirrored. The principle of negative film mirroring: the drug film surface (that is, the latex surface) is applied to the drug film surface to reduce the error. The determinant of the mirror image: craftsmanship. if

If it is a screen printing process or a dry film process, the copper surface of the substrate on the film side of the film shall prevail. If the diazo film is used for exposure, since the diazo film is a mirror image when copied, its mirror image should be that the film surface of the negative film is not attached to the copper surface of the substrate. If the light painting is a unit

Negatives, instead of imposing on the light-painted negatives, you need to add another mirror image.

2. Determine the parameters of solder mask enlargement.

Determine the principle:

① Do not expose the wire next to the pad.

②Small can't cover the pad.

Due to errors during operation, the solder mask may have deviations on the circuit. If the solder mask is too small, the result of the deviation may mask the edge of the pad. Therefore, the solder mask should be larger. But if the solder mask is enlarged too much, the wires next to it may be exposed due to the influence of deviation.

From the above requirements, it can be seen that the determinants of solder mask expansion are:

①The deviation value of the position of the solder mask process of our factory, the deviation value of the solder mask pattern.

Due to the different deviations caused by various processes, the solder mask enlargement values corresponding to various processes are also different. The enlargement value of the solder mask with large deviation should be selected larger.

②The board wire density is large, the distance between the pad and the wire is small, and the solder mask expansion value should be selected smaller; the board wire density is small, and the solder mask expansion value can be selected larger.

3. According to whether there is a printed plug (commonly known as golden finger) on the board to determine whether to add a process line.

4. Determine whether to add a conductive frame for electroplating according to the requirements of the electroplating process.

5. Determine whether to add a conductive process line according to the requirements of the hot air leveling (commonly known as tin spraying) process.

6. Determine whether to add the center hole of the pad according to the drilling process.

7. Determine whether to add process positioning holes according to the subsequent process.

8. Determine whether to add the outline angle according to the board shape.

9. When the user's high-precision circuit board requires high line width accuracy, it is necessary to determine whether to perform line width correction according to the production level of the factory to adjust the influence of side erosion.