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Slide 001: CNC Plasma Table Components & Setup

Slide Visual

CNC Plasma Table Components & Setup

Slide Overview

This slide introduces the major components of a CNC plasma cutting table and their functions. Students will learn the complete system architecture from power supply to motion control to fume management.

Instruction Notes

CNC Plasma Table Architecture

A CNC plasma table combines a plasma power supply with a gantry-style motion system, torch height controller, and cutting surface. Key subsystems:

Motion System - Gantry: Steel bridge spanning the table width, moves along Y-axis on precision rails - Torch carriage: Rides on the gantry, moves along X-axis - Drive system: Rack-and-pinion (most common for plasma tables due to long travel), stepper or servo motors - Controller: Dedicated plasma CNC controller (e.g., Mach3/4 with plasma plugin, LinuxCNC with PlasmaC, or dedicated controllers like Hypertherm Edge Connect)

Torch Height Control (THC) The THC system is critical for plasma cutting β€” it maintains the correct torch-to-work distance by monitoring arc voltage: - Arc voltage: Proportional to torch standoff. Higher voltage = greater distance - Target voltage: Set based on amperage and material (typically 95-145V DC during cutting) - Response time: THC adjusts Z-axis height in real-time (10-50 times per second) - IHS (Initial Height Sense): Detects the workpiece surface before each pierce using ohmic contact or float switch

Cutting Surface - Water table: Steel tank filled with water to just below the workpiece. Captures fumes (90%+), reduces noise, cools parts - Slats: Replaceable steel supports that hold the workpiece above the water. Spacing: 2"–4" apart. Must be replaced as they get cut up - Downdraft table (alternative): Uses exhaust fans below the cutting surface to draw fumes down. More expensive but no water management

Air Supply System Clean, dry air at 60-75 PSI is critical: - Compressor β†’ water separator β†’ coalescing filter β†’ desiccant dryer β†’ particulate filter β†’ plasma cutter - Minimum compressor size: 5 HP / 80-gallon tank for continuous cutting - Air quality standard: ISO 8573-1 Class 4.4.4 or better

Plasma Power Supply - Input power: 208/240V single-phase (smaller units) or 3-phase (60A+) - Output: 20-80A DC at 100-160V (cutting), 200-300V OCV (open circuit) - Duty cycle: Percentage of 10-minute cycle the unit can operate at rated amperage (e.g., 60% duty cycle at 65A = 6 min cutting, 4 min cooling)

Pre-Operation Checklist

Before every session: 1. Water table level correct (touching bottom of workpiece or ΒΌ" below) 2. Slats in good condition and properly spaced 3. Air pressure at 65-75 PSI, moisture indicator green 4. Consumables inspected (electrode pit depth, nozzle orifice condition) 5. Work clamp secure, cables routed away from torch travel path 6. THC voltage set for material/amperage combination

Key Talking Points

  1. The THC is what makes CNC plasma cutting work on real-world (warped/uneven) material
  2. Clean, dry air is the foundation of good plasma cuts and long consumable life
  3. Water table maintenance is not optional β€” low water = high fumes = health hazard
  4. Slats are consumable items β€” budget for regular replacement
  5. Duty cycle limits how long you can cut continuously β€” plan long jobs accordingly

Learning Objectives (Concept Check)

  • [ ] Identify and describe the function of 6 major CNC plasma table components
  • [ ] Explain how the THC system maintains cut quality on uneven material
  • [ ] List the air quality requirements for plasma cutting

Last Updated: 2026-03-19