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Problems with custom pad shape...

Hi Group!

I'm using Orcad PCB (Tiny-Allegro ;-) version 16.2 s28.

I've drawn some custom shapes for pads/soldermask (Halfcircle2mm.ssm and Halfcircel2mm-sm).
When I load them in Padstack Designer (as "Shape" with "Geometry" dropbox="Shape") the preview of the pad is just a vertical line, the soldermask looks like the drawn (but hollow). This seems a bit strange - but preview functions has never been a Cadence selling point. The the "Top" view of "Views" in Padstack designer is just a square - but I think thats a feature that has never worked with custom shapes anyways (?).

Using the padstack (Halfcircel2mm.pad) in a footprint looks as expected. But when placed on a board it seems the soldermask is used for the actual pad. In any case the outline is to big (and pin center is not where it should be).Thus the pads are shorted (and I get the expected "SMD Pin to SMD Pin Spacing" DRC).

I'm at the point where I think I've tried everything at least twice - but I'm hopefully just missing something obvious?

Any input greatly appreciated!

Best regards,
Anders Frederiksen (Denmark)

PS: Relevant design files and a screen shot of the footprint in the editor and placed can be found here hi5.dk/.../CustomPad-failing.zip

redwire over 13 years ago

Seems to be working here with your files.
I did not see a package symbol so I made one using your two half-circles. I have attached an image.
I did not do anything to your symbols in the zip to make this work...
- halfsym.JPG
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N i z e over 13 years ago

Hi Redwire,

Thanks for your swift reply! My attemt at a package symbol is SW-solder-2mm.dra/psm.

Your symbol looks "functional" - but I suspect it actually has the same problem as all of my attempts: The (should be smaller) copper is the same as the solder mask when placed(?). It's even more strange now that I moved the origin of the copper shape (halfcircle2mm.ssm) so they do not align correctly when editing the symbol (but when the symbol is placed copper and solder mask are perfectly aligned and same size!)...

Do your symbol have differing solder mask and copper when placed? If so: What version are you using?

I guess I might try (again!) to draw the copper pad shape. But I'm still totally puzzled about Allegro changing it for the solder mask shape - even if the copper shape is flawed! I'm not a big fan of software "acting on it's own" - unless it's doing "right" things... ;-)

Thanks and best regards,

Anders

Editing symbol (pad and soldermask are both correct - although not correctly aligned):

Placed symbol (solder mask and pad exactly the same - note the pad is also moved!):
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N i z e over 13 years ago

Hi Redwire,

Thanks for your swift reply! My attemt at a package symbol is SW-solder-2mm.dra/psm.

Your symbol looks "functional" - but I suspect it actually has the same problem as all of my attempts: The (should be smaller) copper is the same as the solder mask when placed(?). It's even more strange now that I moved the origin of the copper shape (halfcircle2mm.ssm) so they do not align correctly when editing the symbol (but when the symbol is placed copper and solder mask are perfectly aligned and same size!)...

Do your symbol have differing solder mask and copper when placed? If so: What version are you using?

I guess I might try (again!) to draw the copper pad shape. But I'm still totally puzzled about Allegro changing it for the solder mask shape - even if the copper shape is flawed! I'm not a big fan of software "acting on it's own" - unless it's doing "right" things... ;-)

Thanks and best regards,

Anders

Editing symbol (pad and soldermask are both correct - although not correctly aligned):

Placed symbol (solder mask and pad exactly the same - note the pad is also moved!):
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redwire over 13 years ago

Ok, I see the problem now that you are seeing. It looks like something is cached wrong.
I have not solved it yet but I would suggest redoing the part with new names for each piece. You should *not* be seeing what you are seeing. Unfortunately I am out for a few days and can't help solve this until later this week. Hopefully someone else can help fix it.
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steve over 13 years ago

I think this is related to the origin points of your ssm files. You need to make sure that 0,0 is located in the correct place. When you load the ssm file into Pad Designer (and then PCB Editor) it uses this 0,0 location. I did move your origin points to get a better overview. I did also use v16.5 (not sure of there is a different behaviour in the latest release).
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