Avid CNC Plasma Introduction¶

Plasma Process Overview¶

CNC plasma cutting is an excellent way to process sheet metal quickly and easily.

In order to ensure successful cutting and quality parts from a CNC plasma cutter, users must have a good understanding of plasma cutting process.

1. Safe Height / Retract Height

• At rapid clearance height the machine moves to the XY pierce position and begins the material touch-off.

2. Material Touch-Off

• The torch moves down until the torch tip makes contact with the material and the "Ohmic Probe" signal reads "Active" in Mach4.
• The Z height is set to Z = 0.

3. Pierce Start

• The torch is moved up to the programmed Pierce Height.
• The torch fires. This starts the programmed Pierce Delay time to allow the arc to fully pierce the material.

4. Pierce Complete

• When the arc transfers to the material, the torch will send an "Arc Okay" signal triggering the Delay After Arc OK which inhibits Torch Height Control (THC) motion.
• After the Pierce Delay the arc has fully pierced the material and cutting motion can begin.

5. Cut Start

• The torch is moved to the programmed Cut Height.
• XY Motion starts.

6. Main Cut

• After the Delay After Arc OK time, THC may be active IF enabled by the g-code AND the Anti Dive rules allow it.

Ohmic Probe Overview¶

The Ohmic Probe senses the top surface of the material in order to set a local Z axis reference for pierce and cut heights. The circuit sends the Ohmic Probe Active signal to Mach4 when an electrically conductive path between the Ohmic Ring (on the torch) and the ground wire (on the material clamp) is completed.

Plasma Software Overview¶

There are three pieces of software necessary for proper use of the Avid CNC plasma system. Ensuring that all software is installed and correctly configured prior to attempting any cutting operations is critical to your success.

1. CAD Software

This program is used to draw or model the geometry to be cut and output a DXF file of the geometry. VCarve Pro is a common option but any software than can export a DXF can be used as a CAD software to design plasma cut components.

2. SheetCam CAM Software

SheetCam is used to create toolpaths and gcode from an imported DXF. Using the Avid CNC Post Processor and Toolsets for SheetCam ensures that the output gcode is appropriate for Mach4 plasma use.

When properly configured, SheetCam can produce g-code which represents the cut profile, speed of cut, target arc voltage (cut height with Torch Height Control), and other parameters required to execute a successful cut. Geometry based settings to enable/disable Torch Height Control may also be exported as part of the g-code.

3. Mach4 CNC Control Software

Mach4 interprets the gcode file and commands the machine motion. It is also responsible for Torch Height Control (THC).

Next Steps¶

The following instructions will walk you through installing required software, setuping up your machine, and making your first cuts with your PRO CNC Plasma system.

1. SheetCam Setup & Users Guide
2. Mach4 Setup Guide
3. Mach4 Plasma Users Guide
4. Plasma First Cut Instructions

Additional Guides (not required for plasma system setup):

1. Plasma Operations Checklist

   The Operations Checklist helps ensure all configuration and setup steps are complete prior to starting cutting operations.