[PCB_FORUM] Re: drill symbols
- From: "westfeldt" <westfeldt_nbcd@xxxxxxxxx>
- To: icu-pcb-forum@xxxxxxxxxxxxx
- Date: Tue, 7 Feb 2006 15:48:18 -0700
Austin makes a good point, but I still keep with padstack holesize=drill
size in nc file=finished hole size in drill legend. I don't want to tell
them exactly what tool to use. Also for vias, the drill legend shows
finished hole size can be much smaller than drill (down to 0 for 12mil and
under via). The way I get around it is to add a fab note for maximum aspect
ratio.
Patrick Westfeldt, Jr.
720-406-0887
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From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Austin Franklin
Sent: Tuesday, February 07, 2006 2:49 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: drill symbols
Hi Leonard,
The only problem I have with a blanket "finished hole size" is that this
gives the fabricator freedom to drill any size they want, which may cause
unwanted spacing issues/DRC violations. DRC is done using what you have
specified as a drill size, unless you have oversized them accordingly in
your design. And, if you have, you might want to put that information on
the print that the hole may not be drilled more than .00n" over (what ever
the oversize in your design is), therefore specifying a limit to their
ability to oversize the hole.
Personally, I specify all hole sizes >= 20 mils is actual drill size, not
finished size. All holes above 20 mils are finished size. There is an
issue with press-fit connectors that, if you are using, you might want to
explore.
Regards,
Austin
-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Leonard E Toohey
(ltoohey)
Sent: Tuesday, February 07, 2006 3:45 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: drill symbols
We have had shops ask if the sizes in the chart are "drill sizes" or the
"finished hole sizes"....
The default chart does say "DRILL SIZE".....
We modified the dlt file to specifically say "FINISHED HOLE SIZE"
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From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Dave Seymour
Sent: Monday, January 23, 2006 2:12 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: drill symbols
Let me re-word the 2nd paragraph.
This way the hole "figure" and the drill "size"are always the same, Now you
have one to one correspondence and one would never run out
of figure combinations.
Dave Seymour wrote:
Gary,
Set the figure as a circle that is the same size as the drill.
Drill Dia = .062
Figure = .062
Character = P ( P= Plated, N = Non-Plated)
width = .062
height = .062
This way the hole and the drill are always the same, Now you
have one to one correspondence and one would never run out
of figure combinations.
Side note: This is how in the old days I would get the drill size to
display,
before the display button was added.
In this electronic age, each of the vendors, techs, engineers I work with
has a copy
of the Allegro viewer or a CAM tool. If anyone wants to "really" know the
diameter, then they hit the "information" button.
Hope this helps.
Dave
Gary MacIndoe wrote:
Hey all,
The padstacks in our library have a unique drill symbol for each drill size
(either a "Figure", a "Character" or
a combination of the two).
This is a "mature" library, and I'm starting to run out of symbols with all
of the odd drill sizes I'm adding lately.
What do you do when all of the combinations are used up? Anybody else have
this problem?
Thanks for a clue!
Gary E. MacIndoe
PCB Design Engineer
Advanced Micro Devices
Longmont, Colorado
--
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560
Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297
Dave.seymour@xxxxxxxxxxxx
<javascript:parent.ComposeTo('Dave.seymour@xxxxxxxxxxxx');>
--
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560
Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297
Dave.seymour@xxxxxxxxxxxx
<javascript:parent.ComposeTo('Dave.seymour@xxxxxxxxxxxx');>
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