Plotting a PCB - Hints

Throughout the production process you should remember that it is very easy to re-plot the PCB if the art work has not turned out quite as you require. Nail polish remover (acetone) will clean up the copper, easily removing the Staedtler ink. Remember also that the bottom layer of the PCB will be flipped. This can cause problems when a combination of surface mount parts and through hole parts are used.

The ink has to be of sufficient density so as to stop the ferric chloride etchant desolving copper where tracking is required. A number of ploys have been tried to achieve this.

1.    Lay the track, within the EasyEdit program, in duplicate.  The settings in
      the Edit program should be such that the track width is the same as the pen width.
      This will cause the pen to draw the track twice directly over.  I think this method
      produces the sharpest tracks, assuming that the three key variables
      are setup correctly.

      The three variables are:-
                               a.    The track width, as set in EasyEdit
                               b.    The pen size, as set in the program
                               c.    The pen size, i.e. the actual tip size.

2.    The combination of the track width and pen tip size, as defined in
       the software, will cause the program to draw a track repeateadly off-setting
       such that the ink lines overlap.  This also has the effect of increasing
       the density of the ink line but you will find that the edges are only one
       coat of ink.  This produces a 'feathered' edge as the etchant may manage
       to penetrate were the ink is thinnest and is not what is required.  Arrange
       the settings as recommeded in (1) above and let the width of the pen tip set the
       track width.

In order to keep the feathering to a minimum you should NOT warm the etchant and if the track width equals pen width there should be no feathering.

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