How To Convert PADs2005 to PCB Gerber File

The Gerber file format is the undisputed lingua franca of the PCB manufacturing industry. As an open 2D binary vector image format, it precisely describes every aspect of a printed circuit board: copper layers, solder mask, silkscreen legend, drill data, and more. By generating a complete set of Gerber files, a designer effectively provides the manufacturer with a set of blueprints, eliminating compatibility issues that can arise from proprietary design file formats. PADS2005, a powerful and historically significant PCB design tool, creates its native files (.pcb and .asc). The critical final step in the design process is accurately converting these files into the universal Gerber format. This guide will walk you through this essential conversion process.

Preparation: Opening Your Design File

Before beginning the conversion, ensure your design is correctly loaded in PADS2005.

• For Native .PCB Files: You can simply double-click the file to open it directly in PADS2005, or within the application, use the toolbar: File → Open (Ctrl+O).

• For ASCII .ASC Files: These files, often used for transferring designs between different tool versions or platforms, must be imported. Navigate to File → Import and select your .asc file.

With your design open, the conversion to Gerber is a multi-step process focused on preparation and accurate output generation.

Step 1: Setting the Coordinate Origin

The first and crucial step is to define a consistent reference point for all output files.

• Action: Press Alt → S → O on your keyboard or select Set Origin from the Setup menu.

• Best Practice: It is highly recommended to set the origin to the lower left corner of your PCB outline. This convention standardizes the coordinate system across all Gerber layers, ensuring perfect layer-to-layer alignment (registration) at the manufacturer. Misaligned layers are a common source of PCB fabrication errors.

Step 2: Managing Copper Pour (Critical for Signal Integrity)

A PCB design is not complete until the copper pours have been properly processed. This step solidifies the copper planes and polygons in your design.

• Action: Navigate to File → Tools → Pour Manager.

• Understanding the Options:

  • Flood: This operation re-electrically fills all copper pours based on your netlist and design rules (clearances, thermal reliefs). Design engineers use this frequently during layout to ensure connectivity and meet DRC requirements. Before output, a final Flood is essential.

  • Hatch: This fills the area based on the customer-defined outline but does not recalculate electrical connectivity. It turns the copper foil outline you see into a solid, “hatched” copper plane. This is the state manufacturers often prefer for final files, as it represents the final copper intent without the tool’s dynamic data.

  • Plane Connect: This is specific to inner layers of multilayer boards that have been defined as Mix/Split planes. These are negative-plane layers where copper is assumed everywhere except where drawn traces and anti-pads exist. Plane Connect is required to process and fill these specialized areas correctly.

Procedure: In the Pour Manager, select Hatch, ensure the Hatch Mode is set to Hatch All, and press Start. For a completely clean state, it is often wise to perform a Flood first, followed by a Hatch.

Step 3: Configuring Design Units and Display

Consistency in units is non-negotiable for a manufacturable design. A mismatch between your design units and Gerber output units is a catastrophic error.

• Action: Access the settings by pressing Ctrl+Alt+Enter or navigating through the menu. Go to Global → Design Units.

• Decision: Set your units to either Mils or Millimeters, whichever you have used consistently throughout your design. Confirm this setting matches the units you will select during the Gerber file export.

• Display Settings: In the same preferences dialog, under Global → Drawing, set the minimum display line width. A useful shortcut to change the display resolution in the main design window is to type R followed by a Space and then a numerical value (e.g., R 1 for 1 mil resolution).

Step 4: Generating the Gerber Files (The Core Output)

This is the main event—translating your PADS design into individual Gerber layers.

• Action: Go to File → CAM.

• Setup: The CAM (Computer-Aided Manufacturing) dialog will open. Here you define the output “jobs” for each layer. You may need to load or create a CAM document.

• Adding Layers: For each required layer (Top Copper, Bottom Copper, Top Solder Mask, Bottom Solder Mask, Top Silkscreen, etc.), you will add a new item.

  • Select the Add button or right-click in the document list.

  • In the Add Document dialog, assign a clear name (e.g., “Top Layer”).

  • For Document Type, select Routing for copper layers and Silkscreen for legend layers. Solder Mask layers also have their specific type.

  • Click OK.

• Configuring a Layer (e.g., Top Layer): A new setup dialog will appear.

  • Layer Association: Select the corresponding PCB layer from the dropdown (e.g., Top for the top copper layer).

  • Output Options: Click Options. Ensure the Device Type is set to Gerber. Crucially, verify that the Units and Format (e.g., 2:5 for 0.01mil resolution or 3:5 for 1 micron resolution) match your design intent and are acceptable to your manufacturer. A format of 2:5 is a common and precise choice.

• Repeat: Add and configure a document for every single layer required for fabrication, including all copper, mask, silkscreen, and paste layers. Don’t forget mechanical layers like the board outline (often on a separate layer or included with the silkscreen).

• Running the Output: Once all documents are configured, select the ones you want to generate and click the Run button. PADS2005 will generate the individual Gerber files (e.g., top_layer.pho, top_soldermask.pho) in your specified output directory.

Final Recommendation: After generating your Gerber files, always use a free Gerber viewer like GC-Prevue or ViewMate to inspect each layer thoroughly. This final verification allows you to catch any potential errors before sending the files to your manufacturer, saving time and cost. By following this detailed guide, you can confidently convert your PADS2005 designs into accurate and manufacturable PCB Gerber files.

2nd step is Click the toolbar File→Tools→Pour Manager to call up the copper menu in the figure below to select Hatch, Hatch Mode to select Hatch All, press Start to make copper, and press Setup to open Perferences (Ctrl+Alt+G) to system parameters. Some appropriate settings:

Flood: Re-electrically fill all according to the Net-list and Design Rules settings. This item is commonly used for design engineers to layout copper foil on the PCB Board.

Hatch: Filling according to the fill area defined by the customer, that is, turning the copper foil profile seen in the file into a large copper foil. (The circuit board manufacture will use to restore the copper foil plating).

Plane Connect: A special filling area set in the inner layer of the multi-layer PCB board. When the layer property of the multi-layer printed circuit board is the plane dividing surface attribute of the Mix/Splix plane, the Plane Connect is required to fill the copper;

3rd step is to change the unit, Global→Design Units; change the minimum display line width Global→Drawing (in the graphical interface can be set by R+space+value)

the 4th step is Change the fill mesh of the copper skin Global→Design Units, fill direction Drafting→Direction; the value of the Copper in the Hatch Grid is the center-to-center distance of the line filled in the large copper foil.