I am from ALLPCB, a PCB fab focus on offering free expedited PCB prototype service, here I would like to tell you how we deal with the CAM, this is only my own opinion and DON’T on behalf of any engineer or any PCB fab.
Usual processing steps:
1. Check the file customer offered (PCB files usually in Gerber file, pcb, pcbdoc or cam file)
1) Check if the disk file is intact
2) For Gerber file, confirm it has the D code or not.
2. Check if the design will conform to the factory's technological capacity:
1) Different spacing like trace to trace, trace to pads, pads to pads, all the spacing needs to be no less than the min spacing which the factory can process.
2) Check the trace width, the min trace width should be no less than the min width which
the factory can do.
3) Check the min drill hole size, it should be no less than the min hole which the factory
can make
4) Check the size of the pads and annular ring to insure the edge of the pad remains a
certain width after drilling.
3. Confirm the specifications customer needed:
1) Does the film require mirroring
2) Confirm the size that need to be extended for solder resist:
Maximum can’t expose the trace in the edge of the pads.
Minimum can’t cover the pads.
Due to the deviation on operation, the resistance diagram may produce deviation on the
trace, if the solder resist is too small, the deviation could result to cover the pad edge,
so the solder resist should be larger, but if the solder mask expand too much, due to the
influence of deviations, the adjacent trace may be exposed. Therefore, the solder resist is
enlarged
, The factors for enlarge the solder resist are as below:
1) The deviation area of the fab technology position and the solder resist pattern
.different tech will result to differ deviation, so the corresponding solder process
expansion size will be different.
2) If the trace density of the board is large, and the spacing between the pas and trace is
small, the the solder resist size should be expanded.
3) If there's a golden finger in the board, then need to confirm to add the technics trace
4) Check the requirements of electroplating process, confirm whether to add the
electroplating conductive frame or not.
5) Check HASL requirement, confirm to add the conductive processing trace
6) Check the drill technology, confirm to add the pad center hole or not
7) Confirm to add the mounting hole or not
8) Check the outline and confirm to add the contour line or not.
9) When high precision board requires high precision of the trace width, confirm to adjust
the trace width or not.
4. CAD files convert to Gerber files
All CAD files need to be converted to the standard plotter format Gerber file.
5. CAM processing
While the spacing is too small, it will need to be compensate accordingly.
6. Gerber output
7. Darkroom processing
The following processing should be strictly controlled
1) Developing time
Affect the optical density and contrast grade
2) Fixing time
If time is not enough, then the base plate color will not transparent
3) Washing time
If the washing time is not enough, the film will be yellow
-Thanks
site: Topspeed PCB Prototype Manufacturer - ALLPCB.com
email:dana.zhang@allpcb.com
Usual processing steps:
1. Check the file customer offered (PCB files usually in Gerber file, pcb, pcbdoc or cam file)
1) Check if the disk file is intact
2) For Gerber file, confirm it has the D code or not.
2. Check if the design will conform to the factory's technological capacity:
1) Different spacing like trace to trace, trace to pads, pads to pads, all the spacing needs to be no less than the min spacing which the factory can process.
2) Check the trace width, the min trace width should be no less than the min width which
the factory can do.
3) Check the min drill hole size, it should be no less than the min hole which the factory
can make
4) Check the size of the pads and annular ring to insure the edge of the pad remains a
certain width after drilling.
3. Confirm the specifications customer needed:
1) Does the film require mirroring
2) Confirm the size that need to be extended for solder resist:
Maximum can’t expose the trace in the edge of the pads.
Minimum can’t cover the pads.
Due to the deviation on operation, the resistance diagram may produce deviation on the
trace, if the solder resist is too small, the deviation could result to cover the pad edge,
so the solder resist should be larger, but if the solder mask expand too much, due to the
influence of deviations, the adjacent trace may be exposed. Therefore, the solder resist is
enlarged
, The factors for enlarge the solder resist are as below:
1) The deviation area of the fab technology position and the solder resist pattern
.different tech will result to differ deviation, so the corresponding solder process
expansion size will be different.
2) If the trace density of the board is large, and the spacing between the pas and trace is
small, the the solder resist size should be expanded.
3) If there's a golden finger in the board, then need to confirm to add the technics trace
4) Check the requirements of electroplating process, confirm whether to add the
electroplating conductive frame or not.
5) Check HASL requirement, confirm to add the conductive processing trace
6) Check the drill technology, confirm to add the pad center hole or not
7) Confirm to add the mounting hole or not
8) Check the outline and confirm to add the contour line or not.
9) When high precision board requires high precision of the trace width, confirm to adjust
the trace width or not.
4. CAD files convert to Gerber files
All CAD files need to be converted to the standard plotter format Gerber file.
5. CAM processing
While the spacing is too small, it will need to be compensate accordingly.
6. Gerber output
7. Darkroom processing
The following processing should be strictly controlled
1) Developing time
Affect the optical density and contrast grade
2) Fixing time
If time is not enough, then the base plate color will not transparent
3) Washing time
If the washing time is not enough, the film will be yellow
-Thanks
site: Topspeed PCB Prototype Manufacturer - ALLPCB.com
email:dana.zhang@allpcb.com
Our company is located in Hangzhou, China, join this forum, I wanna to let people know more about PCB Fab in China,nowadays Low prices do not mean low quality, with the rising demand for value for money, I am sure we are able to satisfy more and more customer's requirement.
Dana... please read the rules regarding Vendors. All comments and posts related to ALLPCB are to be kept to this one thread.
Failure to observe this will result in suspension of posting privileges, as will any reports of unsolicited contacting of members via the pm system.
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