RabbitCAM X Support

Plunge Roughing Overview

Plunge Roughing removes bulk material with a series of vertical cutting moves distributed over a machining area. The operation provides one strategy, Plunge, under 3D Operations.

RabbitCAM X builds an XY grid using the tool diameter and Step over. It calculates a separate endpoint for each position from the full Part geometry, the cutting profile, stock allowances, Bottom Level, and modeled Work Holding. Plunges can therefore finish at different depths.

Each plunge returns to Safe Level before the tool moves to the next position. Use subsequent machining operations to remove the material left between plunges and produce the required final surfaces.

Setup Video

Watch SourceRabbit's RabbitCAM X - How to Setup Plunge Roughing video, then use the parameter descriptions below when setting up your operation.

Watch the video on YouTube.

Creating the Operation and Selecting a Tool

1. Prepare a 3D Part, the Stock, a defined Workpiece Coordinate System, and any required Work Holding.
2. Open Machining > New Operation > 3D Operations and select Plunge Roughing.
3. Choose an End Mill, Bullnose, or Ballnose tool, review the operation name, and click Create.
4. Use Job Assignment to define the machining area, then open Strategy to configure Plunge.

The actual cutting profile affects the endpoint, so changing between a flat, corner-radius, and ballnose tool can change the generated depths. Review the tool diameter, cutting length, shank dimensions, and stickout against the intended setup.

Each position uses a continuous axial cutting move. Select a tool suitable for that motion. The current strategy does not automatically cap the plunge depth at the cutting length or split it into shorter depth passes.

Use a Part containing 3D surfaces. A curve-only DXF does not provide the Part geometry required for this operation.

Defining the Machining Area

Open Job Assignment > Pick and choose the selection method:

• Surface or Surfaces (Lasso): select the surfaces whose projected boundaries define the area, then use Finish Surface Selection. Connected selections are handled as Surface Groups.
• Boundary: select a closed topology boundary, then use Finish Boundary Selection.
• Curves: build a closed, continuous chain of curves and use Finish Curve Selection.

Each selection must enclose a measurable area when projected onto XY. A vertical surface alone, an open curve chain, or a broken boundary may not define a usable region.

With no Job Assignment, the operation uses the rectangle enclosing the Stock's XY bounds. This is a valid whole-stock setup. For a local pocket or a smaller area, add explicit assignments.

Selections control where candidate plunges are placed. The depth calculation still checks the full Part, including surfaces outside the selected group. Overlapping assigned regions are combined before the grid is generated, avoiding duplicate grid positions.

Step over and Plunge Positions

Step over sets the nominal distance between neighboring plunge positions as a percentage of tool diameter. The accepted range is 1% to 100%, and the default is 40%.

Plunge spacing = Tool diameter × Step over / 100

For example, a 10 mm tool at 40% gives 4 mm spacing in both X and Y. A smaller value creates more positions; a larger value creates fewer positions and can leave more material between plunges.

The grid is traversed row by row in increasing model Y, with increasing model X within each row. It is not a zigzag cutting path: every retained position has its own descent and retract.

Near walls, RabbitCAM X can shift a position locally to find a deeper accessible plunge while respecting the permitted tool-center region and Work Holding. The shift is limited to one quarter of the nominal spacing, so some final positions may no longer lie exactly on the original grid.

Tool Center: Inside or Outside the Boundary

Tool Center controls the region available to the tool axis before the grid is generated:

• Inside Boundary: the machining region is inset by the cutter radius. This keeps the cutter's circular footprint inside the selected boundary, including clearance from internal islands.
• Outside if Possible: the outer boundary is offset by tool radius minus plunge spacing. Internal islands retain a tool-radius exclusion. This is the default mode.

With Outside if Possible, a Step over below 50% permits centers outside the outer boundary. At 50%, the outer center limit coincides with that boundary; above 50%, it moves inward. Actual plunge depths remain subject to the Part and Work Holding checks.

For a 10 mm tool at 40%, the radius is 5 mm and spacing is 4 mm, so the outer center limit extends 1 mm beyond the boundary. Along an axis-aligned straight stock edge, the first row is positioned for a 4 mm engagement.

A narrow region can disappear after the radius offset in Inside Boundary mode. If no positions remain, review the selected area, tool diameter, and Tool Center setting.

Bottom Level and Stock to Leave

Bottom Level is the lowest permitted tool-tip Z in work coordinates. Enter it directly or use the pick button beside the field. It is a depth limit, not a promise that every plunge will reach that Z.

The calculated endpoint is the highest of the Bottom Level limit, the tool's required clearance from the Part, and the limit imposed by Work Holding. A floor, slope, wall, or wider shank can stop the tool above Bottom Level. Mesh approximation allowances can also place the endpoint slightly above the ideal surface.

• Radial Stock to Leave reserves material around the Part in XY, particularly at steep and vertical walls.
• Axial Stock to Leave reserves material above Part surfaces in the positive Z direction, including horizontal and sloped surfaces.

Both allowances are entered in mm, must be zero or positive, and default to 0 mm. They affect the Part clearance calculation; they are not simply added to Bottom Level everywhere.

For example, with a flat end mill over a horizontal floor at Z-10 mm, an axial allowance of 0.5 mm keeps the tip approximately at Z-9.5 mm, or higher if another limit applies. This assumes Bottom Level permits that depth.

The geometry checks include the cutter and exposed shank. A shank wider than the cutter can limit access. Work Holding uses its own configured Safety Clearance in XY and Z. Holder clearance and the rapid travel route still need to be reviewed separately.

Safe Level and the Motion Sequence

Safe Level is the work-coordinate Z used for travel between plunges and for each retract. It must be higher than Bottom Level. Set it high enough to clear the actual Part, remaining Stock, and fixtures along the travel route.

For each retained position, the current strategy generates:

1. A vertical rapid move from the current position to Safe Level, when required.
2. A rapid XY move to the next plunge center at Safe Level.
3. One linear cutting move from Safe Level to the calculated endpoint, using Plunge Rate.
4. A vertical rapid retract to Safe Level.

The entire descent begins at Safe Level. There is no separate rapid approach to a locally calculated stock top, no Approach Clearance field, and no peck cycle or Depth per Pass setting in this strategy.

The entered Safe Level is used directly and is not raised automatically. Limiting a plunge against Work Holding does not automatically route the XY rapid around an obstacle. Check the initial move, transfers, and retracts in Simulation.

A position is omitted when the calculated endpoint leaves no meaningful downward travel from Safe Level. The operation can produce an empty toolpath if no candidate position can descend.

RPM, Feed Rate, and Plunge Rate

• RPM: the spindle speed in revolutions per minute.
• Feed Rate: the operation's general cutting-feed parameter, in mm/min.
• Plunge Rate: the feed used for the vertical cutting descents, in mm/min.

All three values must be positive. In the current Plunge strategy, the generated cutting moves use Plunge Rate; there are no lateral cutting moves that use Feed Rate. XY transfers and vertical retracts are rapid moves.

Review these values after changing tools. Choose the plunge feed for the actual cutter, material, and axial engagement rather than assuming the normal lateral milling feed is appropriate.

Fill Areas and Current Machining Limits

Enabled Fill Areas contribute covering surfaces to the machining model. These surfaces participate in the plunge-depth calculation. Their coverage is also included in a selected Surface Group where the group matches the fill boundary.

The current strategy generates positions from the machining region and limits their depth against modeled geometry. It does not filter out positions according to remaining stock, so it can include descents through empty space or areas already cleared by preceding operations. Review the simulated material removal as well as the displayed toolpath.

Part-based Restricted Areas are not currently used to trim the plunge positions. Use explicit Job Assignments to control the machining extent and inspect the result. The separate Work Holding depth and Safety Clearance checks are applied.

Generating and Checking the Toolpath

1. Confirm the Part, Stock, Work Zero, Work Holding, and assigned tool.
2. Define Job Assignments, or deliberately leave the list empty to use the Stock's XY bounding rectangle.
3. Set Step over and Tool Center, then review the resulting spacing and intended boundary engagement.
4. Set Bottom Level, radial and axial allowances, Safe Level, RPM, and Plunge Rate. Keep Feed Rate positive.
5. Click Run & Link and inspect the Plunge Roughing toolpath.
6. Open Simulation to check depths, local position shifts, remaining material, tool reach, and every approach, transfer, and retract.
7. Recalculate after changing geometry, assignments, Fill Areas, Work Holding, tools, Work Zero, or strategy settings. Save the project and use Post Process once the setup has been reviewed.

A roughing toolpath does not guarantee a finished surface or complete removal of all material within the selected area. Plan the following operations around the material that remains.

For related setup and machining, see Setting the Workpiece Coordinate System, Setting Up Work Holding, and Waterline Roughing. For export, see JavaScript Post Processors.

Common Problems

• No plunge positions: check whether the selected area is large enough for the tool-center offset and grid spacing. A small region may contain no grid points.
• Positions exist, but no downward moves are generated: the Part or Work Holding may require a tip position at or above Safe Level. Review the setup and levels.
• A plunge stops too high: review Bottom Level, the full cutter shape, stock allowances, nearby Part walls, wider shank sections, active Fill Areas, and Work Holding clearances.
• The path extends beyond the selected outer boundary: review Outside if Possible and the Step over percentage. Use Inside Boundary when the cutter footprint must remain inside the region.
• The path includes already-cleared space: remaining-stock filtering is not currently applied. Narrow the Job Assignment where appropriate.
• An assignment is rejected: check that its geometry still belongs to the current Part and that the selection forms a closed, continuous, measurable XY region.
• Too many candidate points: increase Step over, reduce the assigned area, or choose a suitable larger tool. Very small spacing over a large area can create an excessive grid.
• Invalid parameters or tool: use an End Mill, Bullnose, or Ballnose with valid dimensions; keep Step over within 1–100%, allowances non-negative, Safe Level above Bottom Level, and RPM and both feed values positive.