Starlab CNC Plasma Quick Start Guide

CNC Plasma Workflow Overview

Operating a CNC plasma table involves three distinct stages – designing the part (CAD), generating toolpaths (CAM) and controlling the machine (CNC control). The control software CommandCNC performs the last stage; it does not draw parts or generate toolpaths but runs a specific dialect of G‑code to drive the machine. A typical workflow looks like this:

Create the part in CAD – Draw your design using a CAD or vector‑art program (Corel Draw, Illustrator, Inkscape, etc.).
Generate the toolpaths in SheetCam – Import the drawing into SheetCam TNG, configure units and machine type, define the cutting tool, assign operations and run the post processor to export a G‑code. SheetCam’s Setup Wizard guides you through the initial configuration and helps you select the proper post processor for CommandCNC.
(Optional) Verify the code – Before running a new program, use a CNC simulator to check the generated G‑code for errors.
Run the program in CommandCNC – Transfer the verified G‑code to the CommandCNC control computer, load the program and execute the cut. CommandCNC translates the G‑code into motor commands and handles input/output signals to the machine hardware.

Setting Up SheetCam TNG for Plasma Cutting

When you first run SheetCam TNG the Setup Wizard opens automatically. Follow the prompts to set up units, machine type and the post processor:

Welcome and units – Click Next on the Welcome screen. Select your preferred linear, angular, feed‑rate and time units from the drop‑down menus. SheetCam will convert values entered with different units to your preferred units.
Select machine type – On the third page of the wizard, tick Jet cutting to enable plasma/jet‑cutting controls. You can also tick Rotary cutting if your machine will do milling or routing; either option adds the appropriate controls to the interface.
Choose a post processor – The fourth screen asks you to select a post processor file that matches your controller; for CommandCNC use the Starlab‑supplied post processor system.
Finish – The fifth screen completes the wizard. Click Finish to save your choices. You can later change any settings via Options > Application options or Options > Machine.

Configuring Machine and Material in SheetCam

After completing the Setup Wizard, configure your machine and material:

Enable jet‑cutting mode – Verify that Options > Machine has Jet cutting checked. Disable Rotary cutting to simplify the interface if you only do plasma work.
Define the working envelope – Open Options > Machine and select the Working envelope tab. Click the origin marker that corresponds to your table’s zero point (e.g., bottom‑left corner) and enter your machine’s usable X and Y sizes. Values such as 8 foot and 4 foot are automatically converted to inches.
Set material size and clearance – Go to Options > Job options. Enter the dimensions of your stock material (length, width and thickness) and its position relative to the origin. Set Rapid clearance (height for rapid moves) and Plunge safety clearance to avoid the torch crashing into the workpiece; 0.5″ works well for plasma.

Creating Plasma Tools and Cut Operations in SheetCam

A plasma table needs a tool definition and operation instructions. In SheetCam this is done via the New jet‑cutting tool and New jet‑cutting operation dialogs.

Default tool library – Starlab supplies a set of preset plasma tools. When you install the Starlab post processor, these defaults appear in the tool library with sensible kerf width, feed rate, pierce delay and height settings for common materials. You can copy and modify these presets rather than creating every tool from scratch. If you would like to add a custom tool follow these steps:

Create a plasma tool:
- Click the Create a new jet cutting tool icon. Choose Plasma from the Type drop‑down menu.
- Set a Tool number and a descriptive Name (disable automatic naming to enter your own).
- Enter the Kerf width and Feed rate along with other parameters such as Pierce delay (time to pierce), Pierce height, Plunge rate, and Pause at end of cut. A higher pierce height reduces spatter but should still allow the arc to transfer. If your cutter delays turning off, add a pause at the end of the cut to avoid gouging.
- Click Update operations if you want existing operations that use this tool to inherit the new settings. Click OK to save.
Define a cutting operation:
- Zoom to fit the drawing, then click Create a new jet cutting operation.
- Choose the Contour method – for cutting an exterior shape select Outside offset. Select the drawing layer and your plasma tool (Tool 1). The tool’s parameters set most of the operation values.
- Configure Lead‑ins and Lead‑outs to pierce away from the cut edge and avoid leaving marks. SheetCam offers arc, perpendicular and ramp lead‑ins; choose a style that fits your geometry.
- Place and adjust Start points using the Place cut start point tool. Start points appear as orange “S” markers. Right‑click a start point to override default lead‑in/out sizes where space is limited.
Arrange the part and generate G‑code:
- Use the Nesting button to move the part on the material sheet. You can drag it directly or enter X/Y coordinates in the Pos X and Pos Y boxes.
- Once everything is defined, click Run post processor to generate the G‑code. Select the appropriate post for CommandCNC if prompted and provide a filename for the output file.

Loading and Running G‑Code in CommandCNC

CommandCNC is the control software used with our Starlab CNC systems. It reads the G‑code produced by SheetCam and generates motion commands for the stepper/servo drives. A few key points:

CommandCNC is the control portion of the workflow; it cannot draw or create toolpaths. Use CAD and CAM tools to generate G‑code before loading the file.
The controller uses profiles or configs, stored under linuxcnc/configs/<config name>, to map inputs/outputs, motor tuning and travel directions. A GUI Configurator lets you clone and edit profiles – make a copy before editing to avoid corrupting a working configuration.
[Inference] To run a job:
1. Connect the control PC to your motion controller and power up the table hardware.
2. Launch CommandCNC using the icon for your profile (e.g., plasma). Each profile appears as a separate desktop icon in your control system.
3. Home or zero the machine axes as directed by your table’s manual.
4. Load the .ngc G‑code file generated by SheetCam.
5. Verify that the tool height control (DTHC) is active and that cut parameters (feed override, pierce delay) match your tool settings.
6. Start the program and monitor the cut. Use the feed‑rate override or pause/resume controls to handle issues.
After installing CommandCNC updates, always run the Configurator to update your configs.

Safe Operation and Best Practices

Plasma cutting can be hazardous. Always observe proper safety precautions:

Personal protective equipment (PPE) – Wear safety goggles, protective gloves, long‑sleeve fire‑resistant clothing and steel‑toed boots.
Ventilation – Plasma cutting produces fumes; ensure good air extraction or use a respirator.
Clear the area – Remove flammable materials from the cutting area; sparks can ignite combustibles.
Inspect equipment – Regularly check hoses, connectors and power sources for wear or damage. Replace worn consumables (nozzles, electrodes, swirl rings) to maintain cut quality.

During operation:

Load and secure the material – Ensure the workpiece is flat and clamped or magnetically secured so it cannot shift during cutting.
Set appropriate cutting parameters – Adjust cutting speed, amperage and torch height based on material thickness. Faster speeds work for thin stock (~1/8 in), while thick material requires slower feed and higher amperage.
Start and monitor the cut – Begin the program and watch the machine. Without automatic height control you must manually keep the torch at the correct height. Check cut quality while cutting and adjust parameters if you see excessive dross or poor edge quality.
Optimize cut quality – Choose the correct gas for the material, maintain consumables, and ensure the material is positioned flat and secure. Proper nesting of parts in SheetCam reduces waste and improves efficiency.

Tips for New Operators

Use separate applications for CAD, CAM and control; this modularity lets you choose the best tool for each task and avoids being locked into an all‑in‑one solution.
Practice on scrap material and simulate new G‑code files before cutting valuable stock.
Keep backups of your CommandCNC configs. Clone the working profile before making changes.
Join support forums (e.g., the official Starlab CNC forum) for updates and community knowledge.