1.Drilling and electroplating
If production is a multilayer PCB, and containing buried hole or blind hole, each layer board must be bored with first plating before bonding. If you don't pass this step, then can't connect each other.
After by machine equipment according to the requirements of drilling borehole Kong Bi inside must go Through electroplating (Plated Through Hole technology, Plated - Through - Hole technology, PTH).After Kong Bi internal make metal processing, can make the internal lines of each layer can be connected to each other. Before starting the electroplating, must first clear hole of sundry. This is because the resin epoxy compound after heating will produce some chemical change, and it can cover internal PCB layer, so need to clear out. Remove and electroplating movements will be completed in the chemical process.
2. Multilayer PCB pressing
each single layer must be pressing to make sandwich plate. Pressing action including adding insulation between the layers, and fastened to each other. If there is through several layers of guide hole, then each layer must be repeated. A multilayer wiring on the outside of the two sides, is often only after a multilayer pressing processing.
3. Treatment resistance welding layer, surface screen printing and gold finger plating
Next resistance welding paint coverage on the outermost wiring, so the wiring will not come into contact with the outside plating parts. Screen printing surface is printed on it, to mark the location of the various parts, it will not be able to cover at any wiring or gold finger, otherwise may reduce solder ability or the stability of the current connection. Gold finger parts usually gold plating, which, when inserted into the expansion slot to ensure high quality of the current connection.
4. Test
to test whether there is a short circuit or open circuit PCB can use optical or electronic means testing. Optical methods using scanning to find out the defects of each layer, electronic testing is usually with fly needle detector (Flying Probe) to check all the connections. Electronic testing in search of short circuit or open circuit is precise, but the optical test cans more easily detected incorrect gaps between the conductors.
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