1Introduction
Add Shield Walls helps you turn simple shapes you draw on a user layer into the finished board features that make up an RF shield enclosure. Instead of placing copper, solder mask, and routing barriers by hand, you sketch where the walls and mounting bosses belong, and the tool builds the real, manufacturable features for you.
You draw the shield layout as ordinary lines and circles on a user layer: lines trace where the walls run, and circles mark where the screw-mount bosses sit. Line width and circle size in your sketch do not matter — you control the finished dimensions from the settings in the window. When you run the tool, it reads the shapes from the user layers you designate and generates smooth, connected shield walls with rounded corners, complete with the clearances a shield needs to fit and function.
The tool supports two different shielding approaches, described in Section 4. Most controls apply to one approach or the other, and the window automatically shows only the settings that apply to the method you choose.
2Requirements and Setup
- Siemens EDA Xpedition (formerly Mentor Graphics) must be running with the PCB design open before you start the tool.
- A valid ExactCAD license must be applied. If no license is found, the tool will tell you to run the ExactCAD Licensing tool first.
- Your design should already have a board outline defined, since several operations reference it.
- The shapes that describe your shield layout should be drawn on a user layer (see Section 3).
When the window opens it connects to your Xpedition session and loads the board data. The status line at the bottom reads “Loading PCB data is complete. Ready to proceed.” when it is ready. The title bar shows who the tool is licensed to and the license expiration date.
3Preparing Your Source Shapes
Before building anything, draw the layout of your shield on a user layer in Xpedition. Two kinds of shapes are used:
- Lines define where the shield walls run. Draw them as a connected path along the centerline of each wall.
- Circles mark the centers of mounting-hole screw bosses. Place a circle wherever you want a round boss added to the wall network.
The exact line width and circle diameter you draw do not matter — the finished wall thickness and boss diameter come from the settings in the window. Keep mounting-hole circles close enough to a wall that they can connect to it; circles too far from any wall will not be joined.
4Choosing a Shielding Method
At the top of the window you choose how the shield will attach to the board. Your choice changes which settings appear below, so set this first.
| Method | What It Does |
|---|---|
| Surface shields (touch the board on one or both sides) | Builds copper and solder-mask features on the top and/or bottom surface of the board that a metal shield can be soldered down onto. No openings are cut through the board itself. This is the method shown in the screenshot, and it reveals the layer, ground-net, and shield-side settings. |
| Shields go through cutouts in the board | Cuts slots through the board so a shield wall can pass through it, and adds the matching routing barriers and solder-mask pullback around those cutouts. Choosing this reveals the cutout-clearance, route-clearance, route-border, and gate-removal settings instead. |
5Surface-Mount Method Settings
These settings appear when you choose the surface-shield method. The first group tells the tool which user layers hold your drawn shapes and which net is chassis ground.
5.1 Layer and Net Selection
| Control | Purpose & Behavior |
|---|---|
| Chassis ground net(dropdown) | Pick your board’s chassis ground net from this list. The generated shield copper is tied to this net. |
| RF walls output layer(dropdown) | The user layer the finished, full-size RF wall shapes are drawn on. |
| Internal walls source layer(dropdown) | The user layer holding your drawn shapes for the interior walls — lines for the walls and circles for mounting-hole bosses. Line width and circle diameter don’t matter. Leave out any mounting-hole circles that sit too far from a wall to connect to it. |
| External walls / boss source layer(dropdown) | The user layer holding shapes for the outer walls. Only include circles close enough to the board outline to connect to the outer walls. You don’t need to draw the outer wall path itself — the board outline is used for that. |
| RF walls clear layer(dropdown) | A user layer holding polygons that mark areas which must stay completely free of any RF wall objects. Anything you build is kept out of these zones. |
ARX_.5.2 Wall Dimensions and Clearances
These fields set the finished size of the walls and the spacing the shield needs. Type each value in your design’s units.
| Control | Purpose & Behavior |
|---|---|
| External wall thickness(value) | Thickness of the shield walls that are added around the board outline. |
| Internal wall thickness(value) | Thickness of the shield walls in the interior areas of the board. |
| Solder mask clearance(value) | How far solder mask is pulled back from the wall shapes. |
| Screw mount boss diameter(value) | The outer diameter of the mounting-hole screw bosses. A round shape of this size is added wherever there is a circle in your drawn source shapes. |
| Smoothing factor(value, 1–4) | Controls the size of the radii used to blend all the wall shapes together where they meet. A larger number produces larger, smoother blending radii. Must be a whole number from 1 to 4. |
| Mousehole clearance(value) | Sets the clearance used for mouseholes (small reliefs) in the wall shapes. |
5.3 Selecting the Shield Side
With the surface method you choose which side of the board the shield features are built on:
| Control | Purpose & Behavior |
|---|---|
| Shield on top(option) | Builds the shield wall features on the top layer of the board. |
| Shield on bottom(option) | Builds the shield wall features on the bottom layer of the board. |
6Building the Surface-Mount Shields
Once your shapes are drawn on the source layers and the settings are set, use these three actions. They appear as small buttons with labels beside them.
| Control | Purpose & Behavior |
|---|---|
| Add internal walls(button) | Builds the interior shield walls from the shapes on the user layer you designated as the internal-walls source layer. There is no need to select anything first — the tool reads everything on that layer. Before it runs, the tool asks whether you’d like to save the PCB first. |
| Add external walls(to board outline) (button) | Builds the outer shield wall that follows the board outline, using the external wall thickness and the chassis ground net you chose. It also asks whether to save the PCB first. |
| Combine shapes(button) | Merges the separate shield copper pieces (and their solder-mask and placement-barrier counterparts) into unified shapes on each side. Run this after the walls are built to clean up overlapping pieces into single, continuous shapes. |
7Through-Board Cutout Method Settings
These settings replace the surface-method settings when you choose the cutout method. They control how the slots through the board, and the clearances around them, are created.
| Control | Purpose & Behavior |
|---|---|
| Wall thickness(value) | Thickness of the shield wall that passes through the board. |
| Cutout clearance(value) | The gap between the wall surface and the cutout in the board around it. |
| Route clearance(value) | The gap kept between the board cutouts and any nearby copper. A routing barrier is placed at this distance from the cutouts so copper is held away. |
| Solder mask clearance(value) | How far solder mask is pulled back away from the board cutouts. |
| Add solder mask clearance(checkbox) | When enabled, solder mask is pulled back from the board outline by the solder-mask clearance amount as part of the operation. |
| Screw mount boss diameter(value) | The outer diameter of mounting-hole screw bosses, added wherever there is a circle in your drawn source shapes. |
| Smoothing factor(value, 1–4) | Sets the blending radii used where the shapes meet; larger numbers give larger radii. Whole number 1 to 4. |
| Route border clearance(value) | How far the route border is set in from the board outline. The route border is redrawn at this distance inward from the outline. |
7.1 Gate Removal
Gates are deliberate gaps left in a shield wall (for example, where a cable or feature must pass through). The gate-removal settings are available only with the cutout method.
To place a gate, draw a small circle on a user layer at the center of where you want the gap, then select the wall lines along with that circle before pressing the gate action. The tool reports “You must select at least one circle…” if no locating circle is selected.
| Control | Purpose & Behavior |
|---|---|
| Metal-to-metal gate opening(value) | The width of the gap opened in the shield wall at the gate. |
| Overall gate length(value) | The total length of the gate feature, including the part that wraps around the opening in the wall. |
| Create gate openings(action) | Creates the gaps in the source wall lines at the marked gate locations, based on the two sizes above. |
8Mounting-Hole Clearances
These settings keep shield material a safe distance away from mounting holes, and let you clear shield shapes back from holes after the walls are built.
| Control | Purpose & Behavior |
|---|---|
| Clearance for shield conductive shapes(value) | The distance shield copper is held back from mounting holes. |
| Clearance for shield metal(value) | The distance the shield metal shapes are held back from mounting holes. |
| Clear mounting holes(button) | Pulls the shield shapes back from the mounting holes using the two clearances above. |
| Selected mounting holes only(checkbox) | When enabled, only the mounting holes you have selected are cleared. When off, the clearance is applied to all mounting holes. |
9Preparing the Wall Path
These tools tidy up your drawn wall path before you build, by rounding sharp corners into smooth arcs.
| Control | Purpose & Behavior |
|---|---|
| Wall bend radius(value) | The size of the bend radius added to the corners of your drawn wall lines. |
| Add bends to path(button) | Adds fillet arcs at the joints between straight line segments in the shapes you have selected, using the bend-radius value above. This rounds off sharp corners so the finished walls follow smooth curves. |
10Saving and Restoring the Board Outline
Because the cutout method can modify the board outline, you can save the outline to a file beforehand and restore it later if needed.
| Control | Purpose & Behavior |
|---|---|
| Save board outline to a file(button) | Saves the current board-outline shape to a file so it can be recreated later. You choose the file name and location. |
| Restore board outline from a file(button) | Rebuilds the board outline from a file you previously saved, returning it to its earlier condition. |
11Cleanup and Performance Options
| Control | Purpose & Behavior |
|---|---|
| Delete shield objects(button) | Removes all of the shield-wall features the tool previously created — the copper, solder-mask, placement-barrier, and user-layer shield shapes — so you can start over. |
| Clear all shield shapes using objects on CLEAR user layers(button) | Removes shield shapes anywhere the polygons on your clear layer say they should be kept out, clearing those regions of conductive areas, solder mask, and routing barriers. |
| Disable trace removal(checkbox) | Skips the step that removes traces from the shield-wall shapes. Turning this on makes building the walls much faster because the tool no longer has to scan every trace and cut geometry around it. Enabled by default. |
| Disable via removal(checkbox) | Skips the step that removes vias from the shield-wall areas. Like disabling trace removal, this speeds up the build. Enabled by default. |
| Save PCB(button) | Saves the current design immediately. |
12Window Controls
| Control | Purpose & Behavior |
|---|---|
| Keep on top(checkbox) | Keeps the tool window in front of the Xpedition window so it stays visible while you work. On by default. |
| Status line | The line at the bottom of the window reports what the tool is doing and confirms when an operation finishes. Hovering over most controls also shows a short description of that control here. |
| Exit(button) | Closes the tool. |
13Typical Workflow
A common sequence for building a surface-mount shield looks like this:
- In Xpedition, draw your shield layout on a user layer: lines for the walls and circles for the mounting-hole bosses.
- Start Add Shield Walls and wait for the status line to report that the PCB data has loaded.
- Choose the surface-shield method at the top of the window.
- Select the chassis ground net and confirm the source, output, and clear user layers.
- Set the wall thicknesses, solder-mask clearance, boss diameter, and smoothing factor.
- Choose whether the shield goes on the top or bottom side.
- (Optional) Select the drawn wall path and add bends to round its corners.
- Build the internal walls — the tool reads the shapes on your internal-walls source layer, so there’s no need to select them first.
- Build the external walls around the board outline.
- Combine the shapes to merge everything into clean, continuous shield features.
- Apply mounting-hole clearances if needed, then save the PCB.
14Tips and Troubleshooting
| Problem | Solution |
|---|---|
| No walls appear (surface method) | Check that your wall lines and boss circles are actually drawn on the user layer you designated as the source layer. The surface method builds from everything on that layer, so if the layer is empty, nothing is created. |
| The tool won’t start / asks for a license | A valid ExactCAD license must be applied. Run the ExactCAD Licensing tool to apply your license code, then start Add Shield Walls again. |
| It can’t connect to Xpedition | Xpedition must be running with the PCB design open before you launch the tool. |
| A setting I read about isn’t on screen | The window only shows settings for the method you chose. Switch between the surface and cutout methods to reveal the other set of controls. |
| The smoothing factor is rejected | Enter a whole number from 1 to 4. Other values are not accepted. |
| Mounting bosses aren’t appearing | Each boss comes from a circle in your drawn shapes. Make sure a circle is placed at each boss location and that it is close enough to a wall to connect. |
| Building is slow | Leaving trace removal and via removal disabled (the defaults) makes the build much faster. Enable them only when you need traces and vias cut out of the shield areas. |