Advanced Teardrops Creation

Advanced Teardrops Creation is a read-write DFM action that adds teardrops at the entrance of conductors into pads. For drilled pads, teardrops reduce the possibility of disconnections due to drill wander. For undrilled pads, teardrops strengthen the conductor to pad connection for special applications such as flex circuits.

A teardrop can be one of the following shapes:

*        Straight - These teardrops are made up of lines half the width of the conductor drawn directly to the pad.

*        Triangular - These teardrops are made up of lines the same width of the conductor drawn from the edge of the conductor to the pad.

*        Filleted - These are made up of arcs the same width as the conductor drawn from the edge of the conductor bending in towards the pad.

*        Rounded - The action adds a zero length line as Teardrop. The extension point is calculated from the pad center toward the entry point.

*        Oval - The action adds a line that makes the line thicker at the entry point. The extension point is calculated from the entry point to the pad to the entry point of the Teardrop to the conductor.

Note: All teardrop features are tagged with the .tear_drop attribute.

 

Examples of Teardrops creation

 

Before

 

Straight

 

Triangular

 

Filleted

 

Delete Old Teardrops

The option skip was added to the parameter Delete Old Teardrops.

If this option is selected, the action ignores any entry point of a line to a pad if at the entry point the line touches another line with a .tear_drop attribute.

If the entry point of the line to the pad is covered by more than two lines, the entry point will be ignored. The entry point will be reported in a new category: Suspected Teardrop.

Special Reports

The action provides:

*        histograms of the full, one-sided, shortened, missing and problematic teardrops

*        the locations where the conductors were too narrow

*        the pads which were suspected as thermals.

Each of the histograms shows the pad name and count followed by the total count for the category. If there are no reports in the category, nothing is printed. A typical report looks like the following:

JOB : test

STEP : pcb

DATE : 19 Jul 1999

TIME : 15:48:16

Created on GENESIS

Action : Teardrop Creation

Layer : cmp1

 

 

Full Teardrops

==============

Name(Pad) / Count

-----------------

r55 130

r65 7

s65 7

r75 3

s75 1

rect34x75xr5 116

rect70x136xr5 5

rect40x50xr5 45

rect75x34xr5 12

rect50x125xr5 15

rect60x64xr5 2

rect50x66xr5 4

rect75x60xr5 2

 

349 full teardrops were added.

 

Shortened Teardrops

===================

Name(Pad) / Count

-----------------

r55 16

rect70x136xr5 2

rect75x34xr5 8

rect40x50xr5 9

rect50x125xr5 2

rect36x76xr5 2

rect34x75xr5 3

 

42 shortened teardrops were added.

 

Missing Teardrops

=================

Name(Pad) / Count

-----------------

rect34x75xr5 2

 

2 locations are missing teardrops.

Result Attributes

 

Attribute

Description

...full

Number of teardrops in the Full Teardrops category for each layer.

...one_sided

Number of teardrops in the One Sided Teardrops category for each layer.

...shortened

Number of teardrops in the Shortened Teardrops category for each layer.

...missing

Number of teardrops in the Missing Teardrops category for each layer.

...problematic

Number of teardrops in the Problematic Teardrops category for each layer.

...narrow

Number of locations in the Line Too Narrow category for each layer.

...thermal

Number of pads in the Suspected Thermal category for each layer.

full

Number of teardrops in the Full Teardrops category for all processed layers.

one_sided

Number of teardrops in the One Sided Teardrops category for all processed layers.

shortened

Number of teardrops in the Shortened Teardrops category for all processed layers.

missing

Number of teardrops in the Missing Teardrops category for all processed layers.

problematic

Number of teardrops in the Problematic Teardrops category for all processed layers.

narrow

Number of locations in the Line Too Narrow category for all processed layers

thermal

Number of pads in the Suspected Thermal category for all processed layers.