The copper-clad panels along with the drill entry material & a back-up-board are then cut to size.
The standard panel comprises of a 0.062 inch thick base material, with a coating of 18µm ( 0.5 ounce) copper on each side.
With the help of CNC drill machines the through-hole plated and component drills are produced. During this process, spindle speeds of up to 100,000 revolutions per minute are recorded.
Because PCBs must be completley free of grease and dust, they are subjected to rigourous cleaning (e.g. by brushing) before proceeding to the next stage.
Using the previously generated photoplots the resist is exposed to UV light.
Through cyclic construction the exposed panel is developed in a 1% sodium carbonate solution. The PCBs are now ready for plating.
The photoresist is stripped away with a 2.5% caustic potash solution. This lends itself to the immersion and spray coat processes.
The next step is the spraying on of a coat of ammonia solution onto the copper film, getting rid of any excess copper, while the galvanised tin protects the tracks and pads.
Only then will the tin be removed using a nitric acid based tin-stripper. This lends itself to the dipping or spraying processes.
Finally, using the previously generated photoplots the soldermask is exposed to light.
The development of the exposed PCB is in turn achieved through a cyclic construction in a 1% sodium solution. Hence all soldering points and pads, which are to be tin plated later, are cleared of soldermask.
Using a Direct Legend Printer, the silkscreen is immediately printed onto the soldermask. In this process the printhead sprays the screen-print, defined by Gerber data, directly onto the PCB.
At a temperature of 150°C the soldermask is tempered over a period of approx. 60 minutes.
To prevent the panel from moving during routing, it is pinned down onto the routing machine bed.
Under extreme temperatures and pressures the internal layers are laminated with a photosensitive dry resist (LAMINAR 5038).
Using the previously generated photoplots the resist is exposed to light.
Through cyclic construction the exposed inner layers are developed in a 1% sodium carbonate solution.
The next stage is drilling. The following manufacture process is equally valid for both multi-layer and double-sided PCBs.