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Export Rounded Rectangle Pad w/Solder Mask Swell

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robyd View Drop Down
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    Posted: 27 Nov 2012 at 1:41am
Hello,
 
I choose Rounded Rectangle Pad shape for footprint.
 
In User Preferences I enlarged the solder mask by 0.05 mm.
 
When I export to Allegro the Rounded Rectangle Pad shape is built as a shape symbol.
 
In the padstack solder mask shape is similar to pad shape, but in the PCB Footprint Expert display I see that the solder mask is 0.05 larger than the pad. Is this OK ?
 
I except to see 2 shape symbols defined one for the pad and the other for the solder mask and then combined in the pad stack.
 
BTW - since there is also a possibility for paste decrease/increase - it also should be different shape symbol if different from the pad definition.

Thank you
robyd
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Tom H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 27 Nov 2012 at 9:15am
We need to understand what's going on here.
 
You changed the Solder Mask Swell in "Setup > User Preferences > Terminals > (Lead Style)".
 
Then you open the Calculator window and you can visually see the solder mask swell in the Viewer.
 
You open the padstack window and see that the padstack name includes the solder mask swell (like this) -
 
 
 
But when you export to Allegro the Padstack Name is Different and the Footprint Pad Size and Solder Mask Size are the same?
 
Let us know so we can reproduce this issue.
 
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robyd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote robyd Quote  Post ReplyReply Direct Link To This Post Posted: 27 Nov 2012 at 9:45am
Tom,
 
I will try to explain :
 
In PCB Footprint Expert (FPE) solder mask swell looks OK visually and in pad definition and pad name.
 
The question is only about the Allegro scripts/export
 
In Allegro Round Rectangle Pads are not native - so symbol shape / polygon should be defined prior to padstack definition.
 
Since the Solder Mask is 0.05mm wider than the TOP pad ( per side ) a different second symbol shape/ polygon  should be defined for the solder mask.
 
And than the Allegro pad editor combines the two different pads/polygons into one padstack.
 
The Script the FPE is exporting for the allegro contains no lines/code for the expanded symbol shape/polygon of the solder mask - and the solder mask shape is selected same as the TOP pad shape.
 
Below I quote a code from the script ( PSR file - padstack script )
as you can see same shapename (cmplx-r-v10-0) is used for TOP and SOLDERMASK_TOP and PASTEMASK_TOP
 
In case of PASTEMASK swell is defined than  additional different polygon should also be built for it.
 
# Pads
setwindow Form.padedit
FORM padedit layers
 
# TOP
FORM padedit grid row begin_layer
FORM padedit grid change begin_layer,begin_layer TOP
FORM padedit geometry Shape
FORM padedit shapename cmplx-r-v10-0
 
# SOLDERMASK_TOP
FORM padedit grid row SOLDERMASK_TOP
FORM padedit geometry Shape
FORM padedit shapename cmplx-r-v10-0
 
# PASTEMASK_TOP
FORM padedit grid row PASTEMASK_TOP
FORM padedit geometry Shape
FORM padedit shapename cmplx-r-v10-0
 
pse_check
pse_save
pse_exit

I summarize :
When using rounded rectangle pads for allegro export and solder mask or paste mask are different from the TOP pad ( for SMT pads ) - since of the swell definition.
 
The Allegro export should create a psx file for each different polygon size.
 
And the .psr file should combine those different shapes/rounded rectangle pads into one Allegro padstack.

I hope now it is more clear now Smile
 
If not I will try again Cry

Thank you
robyd
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