Tabs
Tabs are small bridges of uncut material that hold a part to the stock during edge routing. Without tabs, a part cut all the way through can shift or fly off the spoilboard when the last pass completes.
Tabs are defined as rectangular regions. When an edge route operation passes through a tab, the tool lifts to the tab's Z Top and resumes cutting after the tab. The result is a thin bridge of material connecting the part to the surrounding stock.
Adding Tabs
There are two ways to add tabs:
- Auto place: Select an edge route operation in the CAM panel and click Auto place tabs. The app places tabs automatically at evenly spaced intervals around the part boundary.
- Manual placement: Select the Tabs root node in the feature tree and click Add Tab. Then click on the canvas to position the tab. Alternatively, click the Tab tool in the toolbar.
Tab Properties
| Property | Description |
|---|---|
| Name | A label for the tab, shown in the feature tree. |
| Shape | Rectangular or Smooth — how the toolpath crosses the tab. See Tab Shape. |
| Z Top | The top of the tab — the height the tool lifts to when passing over the tab. Set this to the stock surface or slightly below to leave a thin bridge. |
| Z Bottom | The bottom of the tab. Usually 0 (the machine table). |
| Visible | Toggles tab visibility on the canvas. |
Tab Shape — Rectangular or Smooth
The Shape property controls how the toolpath gets over the tab. Both shapes have the same footprint and the same Z Top; only the motion differs.
| Shape | How the tool crosses |
|---|---|
| Rectangular | The tool steps straight up at the leading edge, runs across flat, and steps straight back down. The default, and what every tab made before this option existed still does. |
| Smooth | The tool ramps up and back down across the crossing instead of stepping. Easier breakout, less scarring where the tool re-enters, and noticeably faster on a machine whose Z axis is slower than X and Y. |
Editing Tabs
Select a tab in the feature tree to edit its properties. Click Edit Sketch to resize and reposition the tab interactively on the canvas by dragging its control points.
Editing Many Tabs at Once
Tabs and clamps support multi-selection, so a job with a dozen tabs doesn't need a dozen rounds of the same edit. Shift-click or Cmd/Ctrl-click several tabs in the feature tree or on the canvas, or use Select all tabs on the Tabs root node (clamps have the matching Select all clamps).
The properties panel then shows the shared editor for the whole selection — {count} Tabs — and everything you change applies to all of them at once: size, Z range, shape, visibility, and delete. Each edit is a single undo step, not one per tab.
- A selection is never mixed. It holds features, or tabs, or clamps — selecting a tab and a feature together doesn't produce a half-usable editor.
- Differing values stay visibly mixed. A field whose members disagree reads Mixed values and stays that way until you commit a common value, so nothing gets flattened just because you opened the panel.
- Resizing preserves centres. Setting a new width or height keeps each tab where it is instead of re-anchoring them all to one corner.
The Z-range slider snaps to 0.1 mm (0.01 in) while dragging, so a quick drag commits a round number rather than a full-precision value you didn't intend.
Clamps
Clamps represent physical workholding devices on the machine table. Defining clamps in the project allows the toolpath planner to generate safe rapid moves that clear the clamps.
Clamps are shown on the canvas as rectangles. They participate in collision avoidance during rapid moves — the tool will retract to the clamp clearance height before moving over a clamp.
Adding Clamps
Select the Clamps root node in the feature tree and click Add Clamp. Then click on the canvas to position the clamp. Alternatively, click the Clamp tool in the toolbar.
Clamp Properties
| Property | Description |
|---|---|
| Name | A label for the clamp. |
| Z Top (Height) | The physical height of the clamp above the machine table. The tool will clear this height on rapid moves over the clamp. |
| Visible | Toggles clamp visibility on the canvas. |
Clamp Clearances
The project-level clearance settings control how much extra space the tool maintains around clamps. These are set in the Project properties panel:
- Clamp Clear XY — horizontal clearance around clamp boundaries.
- Clamp Clear Z — additional Z clearance above the clamp height on rapid moves.
Collision Highlighting
PureCut CNC flags clamp collisions visually, not just in text. A clamp whose zone the toolpath violates is drawn in red instead of blue, and the specific toolpath moves that pass through that clamp below the required clearance are redrawn in amber on top of the normal toolpath — so you can see exactly where the tool would strike the clamp. Rapid moves that the planner automatically lifts to a safe height are not flagged. Move the clamp or the cut, or increase the clamp clearances, until the amber highlight disappears.
Editing Clamps
Select a clamp in the feature tree to edit its properties. Click Edit Sketch to resize and reposition the clamp interactively on the canvas. Clamps can also be multi-selected and edited together — including Select all clamps on the Clamps root node. See Editing Many Tabs at Once, which works the same way for clamps.