Homebrew PCBs

Hi All,

I have just installed eagle onto my machine after using autotrax for ages. I
have completed my first board and have printed it out in preperation for using
the TTS method to transfer my image to coper. The first thing I noticed was
that the drill hole sizes seem to be the actual drill size. This means that
there is not much copper left in the pad. When using easyplot there was a
'Pad hole guide size' in the setup options that allowed me to make the
drill hole smaller (20mil). This guides the drill bit to the centre when
drilling. Is there an option in eagle to make all the drill hole sizes small
so it makes it easier to drill later.

--
Daryl Sayers                            Home: daryl@...
Scott me up Beamy                       Home: dksayers@...

Two things that can help with what you are attempting to do, 
select "drc" (Design Rules Check) then click the "Restring" Tab, 
Under PADS Top & Bottom, change the % (percentage) to a larger 
number, then click "Apply" button. 

I would suggest that you save your file under some sort of alternate 
file name before testing these procedures. 

( Extracted text from the Eagle "Help.Pdf" file )

Restring
The Restring tab defines the width of the copper ring that has to 
remain after the pad or via has been drilled. Values are defined in 
percent of the drill diameter and there can be an absolute minimum 
and maximum limit. Restrings for pads can be different for the top, 
bottom and inner layers, while for vias they can be different for the 
outer and inner layers. If the actual diameter of a pad (as defined 
in the library) or a via would result in a larger restring, that 
value will be used in the outer layers. Pads in library packages 
usually have their diameter set to 0, so that the restring will be
derived entirely from the drill diameter.

( End extracted "Help.Pdf" text )

The second item is as follows, if you don't have these files they can 
be downloaded from the Cadsoft website and saved in 
your "X:\\\Eagle\ulp" directory. 

From the command line in the Board layout window "Run drill-aid.ulp"

Open the files with a TEXT Editor and read the headers . . .

drill-aid.ulp
Limit drill diameter of pads, vias and holes for easier manual 
drilling. Draws small circles in layer 116 inside the drilling of 
pads, vias and  holes, which should make it easier to center the tool 
while drilling the board manually.

drill-aid-delete.ulp
Allows selective removal of circles in layer 116 inside the drilling 
of pads.

>>>>> "scratch" == scratch 6057 <dml.empsrch@...> writes:

> Two things that can help with what you are attempting to do, 
> select "drc" (Design Rules Check) then click the "Restring" Tab, 
> Under PADS Top & Bottom, change the % (percentage) to a larger 
> number, then click "Apply" button. 

> I would suggest that you save your file under some sort of alternate 
> file name before testing these procedures. 

> ( Extracted text from the Eagle "Help.Pdf" file )

> Restring
> The Restring tab defines the width of the copper ring that has to 
> remain after the pad or via has been drilled. Values are defined in 
> percent of the drill diameter and there can be an absolute minimum 
> and maximum limit. Restrings for pads can be different for the top, 
> bottom and inner layers, while for vias they can be different for the 
> outer and inner layers. If the actual diameter of a pad (as defined 
> in the library) or a via would result in a larger restring, that 
> value will be used in the outer layers. Pads in library packages 
> usually have their diameter set to 0, so that the restring will be
> derived entirely from the drill diameter.

> ( End extracted "Help.Pdf" text )

> The second item is as follows, if you don't have these files they can 
> be downloaded from the Cadsoft website and saved in 
> your "X:\\\Eagle\ulp" directory. 

>> From the command line in the Board layout window "Run drill-aid.ulp"

> Open the files with a TEXT Editor and read the headers . . .

> drill-aid.ulp
> Limit drill diameter of pads, vias and holes for easier manual 
> drilling. Draws small circles in layer 116 inside the drilling of 
> pads, vias and  holes, which should make it easier to center the tool 
> while drilling the board manually.

> drill-aid-delete.ulp
> Allows selective removal of circles in layer 116 inside the drilling 
> of pads.

Many thanks.
I was unable to manipulate the drill hole size with the restring. changing
the percentage seemed to only enlarge the pad itself. The drill-aid.ulp
however did exactly what I wanted so I am now a happy chappy.

-- 
Daryl Sayers                             Direct: +612 95525510
Corinthian Engineering                   Office: +612 95525500
Suite 54, Jones Bay Wharf                   Fax: +612 95525549
26-32 Pirrama Rd                          email: daryl@...
Pyrmont NSW 2009 Australia                  www: http://www.ci.com.au