What is the D code of Gerber Files?
D code, simply speaking, the first character is "D". There are
three D codes in the Gerber files that are used to control the
desktop to move along X-Y location.
D01 (D1): Open the shutter and move the desktop to the
corresponding X-Y coordinates.
D02 (D2): Close the shutter and move the desktop to the
corresponding X-Y coordinates.
D03 (D3): Open the shutter and move the desktop to the
corresponding X-Y coordinates. Then quickly open and close the
shutter, thus forming an exposure point.
D01 is a command to draw a line; D02 is a command that only moves
the desktop without exposing the film. For example, D01 and D02 are
like the pen stroke line and the pen holder of movement in the
pen-type photoplotter.
D03 is the “flash” command. When the desktop moves, the shutter is
closed. When the desktop moves to the corresponding coordinates,
the shutter opens and closes immediately – this will leave an image
of the aperture on the film. D03 is a very effective command when
drawing pads on a printed circuit board.
The D01, D02, and D03 commands always follow their corresponding
data, as in the following example:
X0Y0D02*
X450Y330D01*
X455Y300D03*
This data will cause the photoplotter to do the following: close
the shutter and move the desktop to the origin; open the shutter
and move the desktop to 450,330; (so draw from 0,0 to 450,330.)
Close the shutter and move to 455,300, open the shutter and close
the shutter.
Aperture mark, D code and D10-D999
Unlike D01, D02, D03, D10 to D999 are data rather than commands,
they are marked on the aperture or on the aperture wheel. The early
photoplotter used an aperture wheel with 24 holes / groove.
Table 1 is a correspondence table between the optical aperture and
the D code of the early photoplotter.
It can be seen that D10 to D19 are arranged in the normal order,
followed by D70 and D71, and D20 is ranked 13th. From D20 to D29,
the sequence is extended. The aperture number should be 23 when it
is D30, but D72 and D73 are inserted before D30. Most optical
drawing and CAM software require you to input the information
(shape and size) of the aperture according to the D code. A few of
software are required to input according to the aperture number (in
this case, you need to rearrange according to the corresponding
table above).
There’re special D codes between 3 and 9. It is used to represent
special line segments such as dotted lines and dash lines. It is
rarely used now, that is, it is only used by some obsolete
photoplotters.
