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Quick Tutorial: Real-Time Design for Fabrication (DFF)


 

By setting Design for Fabrication (DFF) constraints, you can catch issues in your design before you manufacture and avoid delays or even costly design respins. OrCAD PCB Designer Professional uses visual indicators to flag these issues in real-time as you design, saving you time by correcting the design as you go instead of after completion. This tutorial will show you how to use and configure the Design for Fabrication constraints included in OrCAD PCB Designer Professional, to ensure your board can be efficiently manufactured. If you would like to follow along with this tutorial, you can download the design files here.
 

Step 1: Open your design in OrCAD PCB Designer Professional and open the Constraint Manager by selecting Setup→ Constraints from the menu.
 

Select the Manufacturing Tab in the Worksheet Selector section of the Constraint Manager.
 

Expand the “Design for Fabrication” (DFF) tab to view the available constraints.
 


 

Step 2: Create a Constraint Set (CSet). Select the Annular Ring Worksheet under “DFF Constraint Set”.
 

Click “<Create new>”.  Set the following information:

  • DFFAnnularRingCset: Mask_Rigid
  • CSet Usage: Non-Etch
     

Click OK.
 


 

Set the following values for the Mask_Rigid Constraint Set:
 

All Pins:

  • Missing Mask: ON
  • Pad to Mask: 0.025
     

All Vias:

  • Missing Mask: ON
  • Pad to Mask: 0.025
     


 

Step 3: Assign the Constraint Set. Select the Annular Ring Worksheet under “Design”.
 

Expand Flexi_Stiffener→ Mask. Assign the Mask_Rigid Constraint Set to SOLDERMASK_TOP and SOLDERMASK_BOTTOM.
 

Expand Primary→ Mask. Assign the Mask_Rigid Constraint Set to SOLDERMASK_TOP and SOLDERMASK_BOTTOM.
 


 

Close out of the Constraint Manager Window.
 

Step 4: Place Component “J6”. In the Options Tab, check the box next to “J6”.
 

Place the component on the board under the Cadence logo by using “R” on the keyboard to rotate the component. Click to place.
 


 

Step 5: View the DRC Errors. Place the curser over the DRC Marker to view more information.
 


 

Step 6: Modify the Design Padstack. Right click on any of the pins in J6 and select Modify Design Padstack→ All instances.
 


 

Select the “Mask Layers” tab in the Padstack Editor.
 

Set the following values:
 

Soldermask Top

  • Geometry: Circle
  • Diameter: 1.3
     

Soldermask Bottom

  • Geometry: Circle
  • Diameter: 1.3
     


 

Step 7: Update the design. Select File→Update to Design and Exit.
 

The DRC Errors have been resolved and the DRC Markers are no longer visible.
 


 

By utilizing constraints for common fabrication issues based on your manufacturer’s specific requirements, you can detect and correct any potential issues DURING your design process. Minimize costly design respins and delays during the manufacturing process by ensuring the manufacturability of your designs with Real-Time Design for Fabrication in OrCAD PCB Designer Professional.