Tweco 400 Ultra-Cut(March 2013) - Manual (Page 90)

OPERATION 4-14 Manual No. 0-5163
ULTRA-CUT 400
4. Nitrogen (N
2
) Plasma
• Provides better cut quality on nonferrous materials such as stainless steel and aluminum.
• Can be used in place of air plasma with air shield or carbon dioxide (CO
2
).
• Provides much better parts life than air.
• A good clean welding grade nitrogen should be used.
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 thinner
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.
6. Argon required for Plasma Marking.
B. Shield Gases
1. Compressed Air Shield
• Air shield is normally used when operating with air plasma and oxygen plasma.
• Improves cut quality on some ferrous materials.
• Inexpensive - reduces operating costs.
2. Nitrogen (N2) Shield
• Nitrogen shield is used with Ar/H2 (H35) plasma.
• Provides smooth finishes on nonferrous materials.
• May reduce smoke when used with Ar/H2 plasma.
3. Water Shield
• Water shield should be used only in mechanized applications - never in hand cutting!
• Normally used with nitrogen.
• Provides very smooth cut surface.
• Reduces smoke and heat input to the workpiece.
• Effective up to 3/4 inch (19.1 mm) maximum material thickness.
• Tap water provides low operating expense.