Tiedown Creation DFM Action

Introduction

In Flexible Circuits, tiedowns are often added to prevent copper from peeling from flexible circuits. This DFM identifies and generates tiedowns, reducing the amount of manual work required for generating tiedowns.


Tiedown Identification

A tiedown line will be identified if the following conditions are met:


Tiedown Types


  

In the Tiedown Gasket model, the original copper pad is enlarged to a size that is larger than the coverlay clearance, yet remains under the coverlay layer. By keeping the edges of the copper pad out of the open coverlay clearance, the copper pad is prevented from being peeled away at its edges.
  

In the Tiedown Fingers model, additional lengths of copper pad called "fingers" extend outward from the original copper beyond the coverlay clearance. These "fingers" serve to anchor the original copper pad in its original location, preventing the copper pad from being peeled away at its edges.

 

In the SMD Pad Tiedown model, copper pads are lengthened to extend outward beyond the coverlay clearance. The extended pads prevent the SMD pad from peeling off.