PCB CAM process - the preparation before PCB manufacturing

The Gerber file and specifications of the PCB are the first information obtained by the PCB factory. The operation process engineer of the PCB manufacturer will optimize the gerber files according to the processing capability for its own factory equipments, and then prepare the manufacture instruction (MI) to suit the factory’ capability. The gerber's review, CAM production usually takes a day, and any adjustments to the gerber files need to be confirmed by the electronic engineers. If the design is suitable for factory’s processing, it will definitely reduce the manufacturing time.

At present, traditional rigid boards still occupy an absolute share in PCB. IPC6012b is the basic basis for engineers and factories to carry out PCB design and processing. In addition to familiarity with IPC6012b, electronic engineers need to understand the various process capabilities of the required PCB processing plants in PCB design. For general rigid PCB manufacturers, it is probably as follows: line width / line spacing 3mil / 3mil, minimum mechanical drill size 8mil, minimum laser drill size 4mil, except BGA minimum PTH hole to hole distance 8mil. The design of the limit will lead to the reduction of the product qualification rate and the increase of the cost. It is recommended to examine the process capability of the PCB processing manufacturer as much as possible in the design and refer to the quotation of each PCB manufacturers.

The minimum design of the line width/line spacing, hole, BGA, etc. on the circuit diagram directly affects the yield and thus the processing cost. We should try to make these designs as large as possible under the reasonable layout of the circuit. In the manufacturing process, a single board is usually panelized to suit the production line. Since the cutting of copper clad laminate is relatively fixed, sometimes it is not helpful to reduce the cost by making smaller PCB size. It is recommended to communicate with the PCB factory product engineers to understand the material utilization rate of the design board and listen to the recommendations and try to achieve the maximum utilization of the PCB board to reduce the price.