PCB circuit board light drawing (CAM) operation flow

- Aug 11, 2017-

Check the user's file

The user's files must be checked for the first time:

1, check whether the disk file is intact;

2, check if the file contains a virus, and if you have a virus, you must first kill the virus;

3, if the Gerber file is checked for D code or D code contains.

(two) check whether the design conforms to the technological level of our factory

1 check whether the design of the spacing in the customer file conforms to the process in our factory: the distance between the line and the line and the distance between the line and the pad the distance between the pad and the pad. The spacing above shall be greater than the minimum distance that can be achieved by the manufacturing process.

2, check the width of the wire, requiring the width of the wire should be greater than the smallest of the factory's production process


3 check the size of the through hole to ensure the minimum pore size of the manufacturing process.

4 check the size of the pad and its internal bore to ensure the width of the pad edge after drilling.

(three) determine the process requirements

Determine various process parameters according to user requirements.

Process requirement:

1, after the process of different requirements, to determine whether the light painted film (commonly known as film) mirror. The film mirror principle: the membrane surface (i.e., latex surface) attached to the membrane surface, to reduce the error. Determinants of negative image: process. If is the screen printing process or dry film process, the film pellicle surface substrate surface for copper. If it is exposed by diazo film, the diazo film copy image, so the image for the film pellicle surface with substrate surface of copper. If the light when plotted as a unit rather than the imposition in the film, light painting film, is more a mirror.

2, determine the parameters of the solder extension.

Determination principle:

One should not reveal the wire beside the pad.

Small can not cover the pad.

Due to the error in operation, the solder resist diagram may cause bias to the line. If the solder is too small, the offset result may cause the edge of the pad to be concealed. Therefore, resistance welding should be greater. But if solder bonding is extended too much, due to deviations, the adjacent wires may be exposed.

From the above requirements, we can see that the decisive factor of resistance enlargement is:

The deviation value of the welding process position and the deviation value of the welding pattern.

Because the deviations caused by various processes are different, therefore, the welding resistance enlargement values of various processes are also different

Different. The deviation of resistance welding big expansion value should be bigger.

The wire board density, distance between the pad and the solder wire, expand the value should be smaller; plate

The sub wire density is small, and the solder resist enlargement value is optional.

3, according to whether the board has printed plug (commonly known as gold finger) to determine whether to process art line.

4, according to the electroplating process requirements, determine whether to add electroplating conductive border.

5, according to the "hot air leveling" (commonly known as tin spray) process requirements, determine whether to add conductive process line.

6, according to the drilling process to determine whether to add pad central hole.

7, according to the sequence process to determine whether to add process positioning hole.

8, according to the shape of the board to determine whether to add contour line.

9, when the user requires high accuracy board width accuracy is high, according to our factory production level, determine whether to carry out line width correction, to adjust the influence of side corrosion.

(four) CAD files are converted to Gerber files

In order to unify the management in the CAM process, should convert all CAD files for photoplotter standard format Gerber and D code.

In the process of conversion, attention should be paid to the required process parameters, as some requirements are to be completed in the conversion.

Now a variety of general CAD software, in addition to Smart, Work and Tango software, can be converted to Gerber, the above two kinds of software can also be converted to Protel format through tool software, and then transferred to Gerber.

(five) CAM processing

Process various processes according to the established process.

Special attention must be paid to whether there is any space in the user file that is too small and must be dealt with accordingly

(six) draw output

After the CAM has been processed, the document can be drawn out.

Make up work can be carried out in CAM, but also on output.

A good drawing system has a certain CAM function, and some process processing must be done on the plotter, for example, the line width is positive.

(seven) the darkroom processing

The painted film needs to be developed and fixed to be used for subsequent process. Darkroom processing, to strictly control the following link:

The developing time: effects of light density production plate (commonly known as blackness) and contrast. Time is short, the optical density and contrast are not too long, fog heavier.

The fixing of the fixing time: time is not enough, then the production master color is not transparent.

Do not wash time: such as washing time, variable production master huang.

Special note: do not scratch the film pellicle.

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