How to make little holes in the pads centers printing from Gerbview?

[klui_]

It's used during manual board making for centering a drill.

Regards,
Vladimir Kalyaev.



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[axtz4]

Post by klui_
It's used during manual board making for centering a drill.

For home-made boards, rather than using the "plot" command to create
gerbers, use the "print" command and print exact 1:1 for each layer.
That way the layers print as they appear on the screen with the
correct width and with open holes in the pads.

Depending on the method you use to prepare the board for etching you
may need to mirror the print, of course.



Please read the Kicad FAQ in the group files section before posting your question.
Please post your bug reports here. They will be picked up by the creator of Kicad.
Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library.
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[Vladimir Kalyaev]

Subject: [kicad-users] Re: How to make little holes in the pads centers printing from Gerbview?

If I'm not mistaken "Print" prints out FULL-SIZED holes, not SMALL centering hole!
Other explanations: for .6-8mm drill open area should be 0.2-0.3mm.
For 0.8mm thru-hole element a drill open area produced by "Print" command equals to the drill diameter. I think it's impossible to use 0.8mm open area for centering a 0.8mm drill!

In OrCAD there is an option "keep drill holes open" which produces a same-sized holes for each thru-hole element.
I can write a script for overruding every thru-hole padshape to force a "Print" command work correctly. Is it an only way?

Excuse me for my bad english...

Post by axtz4

Post by klui_
It's used during manual board making for centering a drill.

For home-made boards, rather than using the "plot" command to create
gerbers, use the "print" command and print exact 1:1 for each layer.
That way the layers print as they appear on the screen with the
correct width and with open holes in the pads.

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[Juan Franco]

Post by Vladimir Kalyaev
Subject: [kicad-users] Re: How to make little holes
in the pads centers printing from Gerbview?
If I'm not mistaken "Print" prints out FULL-SIZED
holes, not SMALL centering hole!
Other explanations: for .6-8mm drill open area
should be 0.2-0.3mm.
For 0.8mm thru-hole element a drill open area
produced by "Print" command equals to the drill
diameter. I think it's impossible to use 0.8mm open
area for centering a 0.8mm drill!

Hi Vladimir,
You can also plot your board to a PostScript file. In
the plot dialogue there is an option to plot drill
holes as Real Size, Small Marks or none.
If you don't have a PostScript viewing software you
may need to install GhostScript + viewer
Regards,
Juan


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Please post your bug reports here. They will be picked up by the creator of Kicad.
Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library.
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[Alain M.]

Post by Vladimir Kalyaev
If I'm not mistaken "Print" prints out FULL-SIZED holes, not SMALL centering hole!
Other explanations: for .6-8mm drill open area should be 0.2-0.3mm.
For 0.8mm thru-hole element a drill open area produced by "Print"
command equals to the drill diameter. I think it's impossible to use
0.8mm open area for centering a 0.8mm drill!

I did some tests (some years ago) and I finaly settled that holes *half
the real size* are ideal. That is because dril centers are bigger for
bigger drills, if you have a .8mm center for a 3.2mm hole it is just
useless. What I used to do was to define all my pads with half the real
diameter and fix that in the docs acompanying the drill file...

Alain

Post by Vladimir Kalyaev
In OrCAD there is an option "keep drill holes open" which produces a
same-sized holes for each thru-hole element.
I can write a script for overruding every thru-hole padshape to force
a "Print" command work correctly. Is it an only way?

Just the same, a script could be made to fix that and generate the print
file. On option could interest some people...

Alain

[KeepIt SimpleStupid]

That's an excellent idea and so is the pilot drill
size. I leared that from a machinist although he
would use something like 1/3.

Post by Vladimir Kalyaev

Post by Vladimir Kalyaev
If I'm not mistaken "Print" prints out FULL-SIZED

holes, not SMALL

Post by Vladimir Kalyaev
centering hole!
Other explanations: for .6-8mm drill open area

should be 0.2-0.3mm.

Post by Vladimir Kalyaev
For 0.8mm thru-hole element a drill open area

produced by "Print"

Post by Vladimir Kalyaev
command equals to the drill diameter. I think it's

impossible to use

Post by Vladimir Kalyaev
0.8mm open area for centering a 0.8mm drill!

I did some tests (some years ago) and I finaly
settled that holes *half
the real size* are ideal. That is because dril
centers are bigger for
bigger drills, if you have a .8mm center for a 3.2mm
hole it is just
useless. What I used to do was to define all my pads
with half the real
diameter and fix that in the docs acompanying the
drill file...
Alain

Post by Vladimir Kalyaev
In OrCAD there is an option "keep drill holes

open" which produces a

Post by Vladimir Kalyaev
same-sized holes for each thru-hole element.
I can write a script for overruding every

thru-hole padshape to force

Post by Vladimir Kalyaev
a "Print" command work correctly. Is it an only

way?
Just the same, a script could be made to fix that
and generate the print
file. On option could interest some people...
Alain

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http://www.yahoo.com/r/hs


Please read the Kicad FAQ in the group files section before posting your question.
Please post your bug reports here. They will be picked up by the creator of Kicad.
Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library.
For building Kicad from source and other development questions visit the kicad-devel group at http://groups.yahoo.com/group/kicad-devel

[Vladimir Kalyaev]

Thanks to all! Plotting to PostScript solved the problem compleately! I dont need a tuning on a Gerber-level to proto boards, so simple PS files are good enough!

KeepIt SimpleStupid : the 1/3 of drill diameter is not a solution in my opinion:
1. for protoboards w/o CNC drill machine it's impossible to make a bull's-eye hit for large drills... I think every hole should be drilled with the smallest diameter (0.8mm in my case). Larger holes drill using 0.8mm as a centering hole.
2. drill's flare angle + copper plane thickness dramatically affects a centering area size.

Juan Franco: some years before a program (using !only! PostScript) for making a `knitting machine punched cards' was written by me =)


Alain M.: using Postscript+small marks for me eliminates a problem compleately (because I drill ALL holes with 0.8mm and later re-drill with the larger diameter).

Regards,
Vladimir.




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