User Guide

Unitsinthe ApertureandDrillTable
When automatically generated with the GERBERAUTO driver, the ap
-
erture table contains values in inches. This is also the case for the drill
table which is automatically written into the drill data file with the out
-
putdeviceEXCELLON.
If your pcb manufacturer insists on mm units for aperture sizes and drill
diameters, you can achieve this by altering the GERBER or
GERBERAUTOrespectivelytheEXCELLONdriver.
In order to do this, use a text editor (one that does not introduce any
controlcodes)toeditthe eagle.def file.Lookfortheline
[GERBER]
or
[GERBERAUTO]
andattheendofthatsectionadd/editthelines:
Units= or Decimals=
Example:
Units=mm
Decimals=4
To avoid problems arising from rounding errors during the conversion,
a toleranceof 61%shouldbeallowedfordrawandflashapertures.
Tochangethedrilltableunitsthere,lookfortheline:
[EXCELLON]
andchange:
Units = Inch to Units = mm
9.10 FilmGenerationUsing PostScriptFiles
Whereas, until a few years ago, Gerber files almost exclusively had to be
generated for the manufacture of professional pcb films, there are today
PostScript raster image recorders which offer a high-quality alternative
whichissimpletohandleandeconomical.
With the PS driver, the CAM Processor generates files in PostScript for
-
mat. These can be processed directly by appropriate service companies
(mostofwhichoperateintheprintindustry).
For PostScript recorders the Width and Height parameters should be set
to very high values (e.g. 100 x 100 inches), so that the drawing is not
spreadoverseveralpages.
Films and drawings that relate to the bottom side are usually output in
mirrored form (Mirror option in the CAM Processor or in the PRINT
dialog).
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PreparingtheManufacturingData