Metal Cutting Plasma Oxy Fuel Band Saw
Plasma Arc Cutting (PAC) • PAC- is a cutting process that uses an arc and a high-velocity, ionized gas coming through a nozzle to cut all metals
PAC • Plasma is A state of Matter • Solid • Liquid • Gas • Plasma is a super heated gas that is ionized. • Ionized- Electrons in the gas have broken away form their atoms and will conduct electricity.
PAC • How it cuts • The plasma gas (compressed air) is forced through a constricting nozzle and heated by the arc which reaches 18,000 to 25,000°F
Advantages of PAC • Can cut all metals • Fast cutting speeds • Little distortion from heat • No hazardous gases
Disadvantages • Plasma Torch is expensive • Not portable (needs electricity) • Metal fumes created can be a health hazard
Safety/ Maintenance • A minimum of a #9 filter shield should be used • Need proper ventilation to remove harmful gases • Dip electrode into anti-spatter compound • Do not allow Pilot Arc to continue for long periods of time
Setting the PAC TorchIf torch amps is set too high travel speed needs to be increased
How to Use • Clean metal • Hook up ground cable • Draw cutting pattern on metal • Hold torch 1/16-1/8” from metal (torch stand will help maintain this) • Hold torch at a 70 to 90° angle • Pull button when arc begins pull torch across metal
Cutting Speed • Too Slow- Molten metal will collect on bottom of work piece and need to be ground off (this is called Dross) • Too Fast- Metal will not be cut all the way through
Oxy-Fuel Cutting
Oxy-Fuel Cutting • Definition:Burning is the rapid oxidation of a material • Does Metal Burn? • Virtually all materials will burn if they are first heated to their ignition temperature. • Steel ignition temp is when it is cherry red, 1300-1400° F • Oxygen burns preheated metal and blows it away from the work piece.
OFC Equipment Combination Cutting Torch with Cutting Attachment Straight Cutting Torch
Harris Calorific - Cutting Tips 3690 Cutting Tip 3690-P Cutting Tip
Tip Cleaner Two Piece One Piece
OFC Cutting Tip Information
Oxy-Fuel Cutting Set-up • All set up the same as oxy-fuel welding except: • To set working pressure for oxygen must open cutting valve
Oxy-Fuel Cutting Process • Clean metal • Draw line • Make jig to keep cut straight • Hold tip 1/16-1/8” above metal • Preheat metal to cherry red color • Open oxygen valve and push torch through metal • (Angle tip slightly toward direction of cut)
Cutting Flame Types Carburizing Flame Neutral Flame Neutral Flame with Oxygen Cutting Stream Oxidizing Flame
AWS Cut Quality Quality Cut Extremely Fast Irregular Pressure Extremely Slow
Troubleshooting
Band Saw
Band Saw • Blade Selection • More teeth/inch= hard metals • Less teeth/inch= soft metals • Blade Speed / RPM • Soft materials= faster / more RPM • Hard Materials= slower / less RPM
Types of Blades
Parts of the Blade
Band Saw safety Rules • Clean oil, grease, and coolant from the floor around the work area • Burrs on cut pieces are sharp. Use special care when handling pieces with burrs. • Check for proper tension on the blade • Use push sticks when cutting small pieces • Be sure all guards are in place before using the saw • Use a brush to clean chips away from the machine • Keep your hands away from moving parts • Stop machine before making adjustments
Chop Saw • Cuts metal with a fiber saw blade
Safety Rules • Always wear safety glasses • Inspect wheel before each use • Clamp all metal before cutting • Support tail of stock with blocks • Watch where sparks are aimed
Metal Grinding
Grinding Wheels • Many different styles available • Make sure to choose correct type of wheel • Test wheel by tapping on wheel with a screwdriver • Good wheel will sound like a bell • Cracked wheel will have a dull thud sound
Safety Rules: • Adjust tool rest to 1/16” from wheel
Safety Rules: • Always wear safety glasses and safety shield • Check for sound wheel before starting • Stand to one side before starting grinder • Hold work by hand or with a clamp or vice grip • Never Wear Gloves • Do not grind on the side of the wheel • Do not adjust or repair while grinder is running • Dress Wheel if needed
Adjust tool rest to proper gap for dressing Turn on grinder Hook dressing tool on tool rest Put light pressure on wheel while moving back and forth Continue until wheel is smooth Readjust tool rest to 1/16” Dressing a Grinding Wheel
Hand Held Grinder
Safety Rules • Always wear safety glasses • Check condition of wheel before each use • Do not remove wheel guards • Use correct wheel for the application • Check condition of electric cord • Use proper tools to change wheel • Watch where sparks are aimed
Types of Discs • Stone grinding wheel • Weld preparation • Fiber Cut-off Wheel • Metal cutting • Flap Sanding Wheel • Metal finishing
