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Profiling - V-Cut scoring

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The final manufacturing stage is to profile the PCBs and cut them out of the production panel. For this we use a computer-controlled milling machine or “router”.  First the machine mills out any small slots or internal cut-outs. The cutter follows the path defined in the original tool file.  Next the milling head automatically picks up a 2 mm cutter, checks the diameter and mills around each PCB.  The brush around the milling head ensures that all the dust produced is collected by the vacuum system. The circuits are held in place by small bridges of material.  We will drill through these and then remove each separate PCB from the production panel.  This panel has also been V-scored.
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Drilling printed circuit boards

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X-ray drill of reference holes Now we drill the holes for leaded components and the via holes that link the copper layers together.  First we use an X-ray drill to locate  targets in the copper of the inner layers.  The machine drills registration holes to ensure that we will drill precisely through the centre of the inner layer pads. Prepare the stacks for drillng To set up the drill the operator first puts a panel of exit material on the drill bed.  This stops the drill tearing the copper foil as it comes through the PCB.  Then he loads one or more PCB panels, and a sheet of aluminium entry foil. Drilling the holes The drilling machine is computer-controlled. The operator selects the right drill program .  This tells the machine which drill to use and the X Y co-ordinates of the holes.  Our drills use air-driven spindles which can rotate up to 150,000 revolutions per minute.  High speed drilling ensures clean hole walls to provide a secure base for good plating on the hol
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Etching inner layer in PCB production

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We remove the unwanted copper using a powerful alkaline solution to dissolve (or etch away) the exposed copper from the inner layer.  The process is carefully controlled to ensure that the finished conductor widths are exactly as designed.  But designers should be aware that thicker copper foils need wider spaces between the tracks.  The operator checks carefully that all the unwanted copper has been etched away. Next we strip off the blue photoresist which protected the copper image.  So now we have the exact pattern required.  The operator checks that all the photo-resist has been removed. You can see that Eurocircuits put several different designs on one production panel.  That way we can make small numbers of PCBs cost-effectively.
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