Tweco 300 XT Ultra-Cut Plasma Cutting System - Manual (Page 69)

ULTRA-CUT 300 XT
Manual 0-5274 OPERATION 4-5
• Can be used in place of air plasma with air shield.
• A good clean welding grade nitrogen should be used.
• When used with a water mist secondary it produces superior cut speeds and cut quality on stainless steel
and aluminum.
5. H17 Plasma (17.5% Hydrogen / 32.5% Argon / 50% Nitrogen)
• Recommended for 1/2 inch (12 mm) and thicker nonferrous materials. H17 is not normally used for thin-
ner nonferrous materials because less expensive gases can achieve similar cut quality.
• Alternative to H35 Plasma. Yields slightly higher cut speeds and similar cut quality.
• When using H17, the gas should be supplied to the gas supply port marked “H35”.
• Poor cut quality on ferrous materials.
B. Shield Gases
1. Compressed Air Shield
• Air shield is normally used when operating with air or oxygen plasma.
• Improves cut quality on some ferrous materials.
• Inexpensive - reduces operating costs.
2. Nitrogen (N2) Shield
• Nitrogen shield is used with nitrogen (N2) or Ar/H2 (H35) plasma.
• Provides smooth finishes on nonferrous materials.
• May reduce smoke when used with Ar/H2 plasma.
3. Water Shield
• Normally used with nitrogen.
• Provides very smooth cut surface.
• Reduces smoke and heat input to the workpiece.
• Effective when used with N2 up to 2 inch (50mm) maximum material thickness.
• Tap water provides low operating expense.