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Metal Cutting. Plasma Oxy Fuel Band Saw Sawz-All Portable Disk (Angle) Grinder. Plasma Arc Cutting (PAC). Cutting process that uses an arc and a high-velocity, ionized gas coming through a small nozzle to cut ALL metals Link:. CNC PAC. CNC http://www.youtube.com/watch?v=XARu4bLXZnM.
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Metal Cutting Plasma Oxy Fuel Band Saw Sawz-All Portable Disk (Angle) Grinder
Plasma Arc Cutting (PAC) • Cutting process that uses an arc and a high-velocity, ionized gas coming through a small nozzle to cut ALL metals • Link:
CNC PAC • CNC http://www.youtube.com/watch?v=XARu4bLXZnM
PAC • 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 • Most plasma cutters require at least 70 PSI
Advantages of PAC • Can cut ANY metal • Torch can’t cut aluminum or stainless, PAC slices right through it. • Super fast setup & cutting speeds • Little distortion (warping) from heat • No hazardous gasses (O2 or Acetylene)
Disadvantages • Plasma Torch is expensive • Portability (needs electricity & compressed air) • 70PSI is need to run most PAC machines • Metal fumes created can be a health hazard
Safety/ Maintenance • A minimum of a #4-5 filter shield should be used • Need proper ventilation to remove harmful fumes • Do not allow Pilot Arc to continue for long periods of time
PAC Setup & Procedure • Clean metal • Hook up ground cable • Draw cutting pattern or template on metal • Place electrode as close to base metal as possible without touching. • 1/16-1/8” from metal • Position torch at a 70 to 90° angle • Pull the trigger & pull torch across metal
Cutting Jigs * Clamp angle iron in place for straight cuts!
Cutting Speed • Too Slow- Molten metal (dross) will collect on bottom • Too Fast- Metal will not be cut all the way through • Sparks may fly upwards
Dross • Most will chip away • Increases with slow travel speeds
Consumables • Electrode • Nozzle • Swirling Ring (orange) • Causes plasma to swirl While these parts are all referred to as consumables, it is the electrode and nozzle that wear and require periodic replacement.
Oxy-Fuel Cutting LINK
Oxy-Fuel Cutting • A torch is used to heat metal to its kindling temperature. • A stream of oxygen is then forced into the metal, burning it into a metal oxide that blows out of the kerf as slag.
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.
Oxy-Fuel Cutting Process • Oxygen (green) 20-23lbs | Acetylene (Red) 5-7lbs • Open cutting valve to set oxygen • Clean metal • Draw line or make jig if straight cut is needed • Hold tip ~ 1/8” above metal • Preheat metal to cherry red color • Open oxygen valve and push • Angle tip slightly toward direction of cut
OFC Equipment Combination Cutting Torch Straight Cutting Torch - Can’t convert for welding or brazing -
Torch Tip • Standard flame exits through outer ring. • Oxygen blasts through center orifice
Flame Types Carburizing Flame – to much acetylene, black smoke, too much carbon Neutral Flame – MINT! Oxidizing Flame - Too much oxygen, hear rushing air, very blue flame
Neutral Flame • Look for a defined blue cone
Cutting Quality – Grain Pattern Quality Cut Extremely Fast Irregular Pressure Extremely Slow
Bending Metal • Metal ductility increases with heat. • Easier to bend and form.
Hardening Metal • Different steels have different methods • Heat steel to ignition temp. (1300-1400*F) • Test with magnet (loses magnetic properties) • Quench in oil (peanut, mineral, motor) for “X” amount of time • Immediately place in an oven to temper. • Steel becomes very hard but becomes brittle You need to do your homework first!
Temperature Indicating (Heat) Sticks • Identifies the temperature of metal • Different sticks melt at different temperatures. • Preheating metal before welding
Safety • Proper PPE • 4-5 Face Shield, pants, gloves, jacket • Keep tanks upright & chained! • Let tanks settle for at least 15 minutes after changeover. • Stand to the side of regulators • Always cap unused tanks • Acetylene tanks ¼ turn max
Band Saw Blades • Teeth Per Inch (TPI) • More teeth/inch= hard metals • Less teeth/inch= soft metals • Blade Speed / RPM • Soft materials: increase RPM • Hard Materials: decrease RPM
Blade Tension • Blade will seize in work piece if too lose. • Blade may snap if too tight. • Tool of choice for long cuts
Guide Adjustment • Tool of choice for long cuts • Adjust guides to ensure a straight cut. • Blade will wonder on long cuts.
Band Saw safety Rules • Burrs on cut pieces are sharp. • Use special care when handling pieces with burrs • Check for proper tension on the blade • Secure piece in vice • Check & adjust guards • Use a brush to clean chips • Keep your hands away from moving parts • Stop machine before making adjustments
Band Saw Operation • Mark metal where cut is to be made • Mount solidly in the vice • Support tail with jack stand • Check tension and condition of blade • Set guide as close as possible • Turn on saw • Slowly open gravity feed (use proper force) • Lubricate with cutting oil • Clean saw when finished
Safety Rule #1 • Keep all guards in place.
Safety Rule #2 • Adjust the blade guards to within 1/8” to ¼” of the stock.
Safety Rule #2 - Continued • Blade guards that are over ¼ inch above the work will lead to accidents and reduces the accuracy of your cut.
Safety Rule #3 • Maintain the stock flat on the table.
Safety Rule #3 - Continued • Never hold the stock ‘above’ the table, the material must remain flat on the table surface at all times.
Safety Rule #4 • Don’t cut round stock on the band saw. • The round stock may roll into the blade causing an accident. • Only the instructor should perform this task while using a miter gauge.
Safety Rule #5 • Concentrate your attention on the job at hand.
Safety Rule #5 - Continued • Do not interrupt others while using power equipment. • Stay focused until the blade has stopped moving.
Safety Rule #6 • Never leave the machine operating while unattended.
Safety Rule #7 • Keep the work area clean.
Safety Rule #7 - Continued • Scrap wood or tools on the floor or the bandsaw table will lead to accidents and injuries.