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Courtyard Excess for TH not applied proportional

Printed From: PCB Libraries Forum
Category: PCB Footprint Expert
Forum Name: Questions & Answers
Forum Description: issues and technical support
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=560
Printed Date: 22 Nov 2024 at 3:14am


Topic: Courtyard Excess for TH not applied proportional
Posted By: jameshead
Subject: Courtyard Excess for TH not applied proportional
Date Posted: 17 Sep 2012 at 3:15am
Settings are as program installed and not changed, i.e.

Setup and Fabrication Level is set to Proportional.

Terminals
    Throughhole
           Lead Widith <= 0.4 mm
           Lead Width > 0.4 mm

In both cases, User and Default Courtyard Excess is equal to 0.25 however no courtyard excess is applied to a axial resistor I tested and courtyard matches 3D body outline.

Withouth changing the "user" setting, i.e. as program is installed with all default .dat files:

If Setup > Fabrication Level is set to Level A then:

Terminals
    Throughhole
           Lead Widith <= 0.4 mm        User = 0.25 and Default = 0.50 
           Lead Width > 0.4 mm           User = 0.25 and Default = 0.50

(should user here, above, default to 0.5 to begin with before the user alters it?)

If Setup > Fabrication Level is set to Level B then:

Terminals
    Throughhole
           Lead Widith <= 0.4 mm        User = 0.25 and Default = 0.25
           Lead Width > 0.4 mm           User = 0.25 and Default = 0.25

If Setup > Fabrication Level is set to Level C then:

Terminals
    Throughhole
           Lead Widith <= 0.4 mm        User = 0.25 and Default = 0.25
           Lead Width > 0.4 mm           User = 0.25 and Default = 0.25

(should this be 0.1 mm or has IPC-7251 changed for new revision? Tom's presentation shows SMT courtyards but not through hole specifically)

I would expect Proportional to have a courtyard excess of some value and the "proportional" only to apply to the pad size.  Personally I don't use Proportional but always create A and B levels.





Replies:
Posted By: Tom H
Date Posted: 17 Sep 2012 at 7:46am
Here are the default rules -
 
Goal

Courtyard Excess

Courtyard Round

Hole Over Lead

Min Annular Ring

Min Fab Allowance

Thermal ID Over Hole

Thermal OD Over ID

Spoke Width Pct

Lead  <= 0.40

Most

0.5

0.02

0.2

0.05

0.55

0.55

0.4

75

Nominal

0.25

0.02

0.15

0.05

0.45

0.35

0.25

75

Proportional

0.25

0.02

0.15

0.05

Calculated

Calculated

Calculated

75

User

0.25

0.02

0.15

0.05

0.45

0.35

0.25

75

Least

0.12

0.02

0.1

0.05

0.35

0.3

0.2

75

Lead > 0.40

Most

0.5

0.02

0.25

0.05

0.6

0.6

0.4

75

Nominal

0.25

0.02

0.2

0.05

0.5

0.4

0.3

75

Proportional

0.25

0.02

0.2

0.05

Calculated

Calculated

Calculated

75

User

0.25

0.02

0.2

0.05

0.5

0.4

0.3

75

Least

0.12

0.02

0.15

0.05

0.4

0.3

0.2

75




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