4PAC Plasma is a super heated gas that is ionized. Ionized- Electrons in the gas have broken away form their atoms and will conduct electricity.
5PACHow it cutsThe plasma gas (compressed air) is forced through a constricting nozzle and heated by the arc which reaches 18,000 to 25,000°FMost plasma cutters require at least 70 PSI
6Advantages of PAC Can cut ANY metal Super fast setup & cutting speeds Torch can’t cut aluminum or stainless, PAC slices right through it.Super fast setup & cutting speedsLittle distortion (warping) from heatNo hazardous gasses (O2 or Acetylene)
7Disadvantages Plasma Torch is expensive Portability (needs electricity & compressed air)70PSI is need to run most PAC machinesMetal fumes created can be a health hazard
8Safety/ Maintenance A minimum of a #4-5 filter shield should be used Need proper ventilation to remove harmful fumesDo not allow Pilot Arc to continue for long periods of time
10PAC Setup & Procedure Clean metal Hook up ground cable Draw cutting pattern or template on metalPlace electrode as close to base metal as possible without touching.1/16-1/8” from metalPosition torch at a 70 to 90° anglePull the trigger & pull torch across metal
11Cutting Jigs* Clamp angle iron in place for straight cuts!
12Cutting Speed Too Slow- Molten metal (dross) will collect on bottom Too Fast- Metal will not be cut all the way throughSparks may fly upwards
13DrossMost will chip awayIncreases with slow travel speeds
14Consumables Electrode Nozzle Swirling Ring (orange) Causes plasma to swirlWhile these parts are all referred to as consumables, it is the electrode and nozzle that wear and require periodic replacement.
17Oxy-Fuel CuttingA 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.
18Does 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, ° FOxygen burns preheated metal and blows it away from the work piece.
20Oxy-Fuel Cutting Process Oxygen (green) 20-23lbs | Acetylene (Red) 5-7lbsOpen cutting valve to set oxygenClean metalDraw line or make jig if straight cut is neededHold tip ~ 1/8” above metalPreheat metal to cherry red colorOpen oxygen valve and pushAngle tip slightly toward direction of cut
21- Can’t convert for welding or brazing - OFC EquipmentCombination Cutting TorchStraight Cutting Torch- Can’t convert for welding or brazing -
22Torch Tip Standard flame exits through outer ring. Oxygen blasts through center orifice
23Flame TypesCarburizing Flame – to much acetylene, black smoke, too much carbonNeutral Flame – MINT!Oxidizing Flame - Too much oxygen, hear rushing air, very blue flame
27Bending Metal Metal ductility increases with heat. Easier to bend and form.
28You need to do your homework first! Hardening MetalDifferent steels have different methodsHeat steel to ignition temp. ( *F)Test with magnet (loses magnetic properties)Quench in oil (peanut, mineral, motor) for “X” amount of timeImmediately place in an oven to temper.Steel becomes very hard but becomes brittleYou need to do your homework first!
29Temperature Indicating (Heat) Sticks Identifies the temperature of metalDifferent sticks melt at different temperatures.Preheating metal before welding
30Safety Proper PPE Keep tanks upright & chained! 4-5 Face Shield, pants, gloves, jacketKeep tanks upright & chained!Let tanks settle for at least 15 minutes after changeover.Stand to the side of regulatorsAlways cap unused tanksAcetylene tanks ¼ turn max
34Band Saw Blades Teeth Per Inch (TPI) Blade Speed / RPM More teeth/inch= hard metalsLess teeth/inch= soft metalsBlade Speed / RPMSoft materials: increase RPMHard Materials: decrease RPM
35Blade Tension Blade will seize in work piece if too lose. Blade may snap if too tight.Tool of choice for long cuts
36Guide Adjustment Tool of choice for long cuts Adjust guides to ensure a straight cut.Blade will wonder on long cuts.
37Band Saw safety Rules Burrs on cut pieces are sharp. Use special care when handling pieces with burrsCheck for proper tension on the bladeSecure piece in viceCheck & adjust guardsUse a brush to clean chipsKeep your hands away from moving partsStop machine before making adjustments
38Band Saw Operation Mark metal where cut is to be made Mount solidly in the viceSupport tail with jack standCheck tension and condition of bladeSet guide as close as possibleTurn on sawSlowly open gravity feed (use proper force)Lubricate with cutting oilClean saw when finished
50Safety Rule #7 - Continued Scrap wood or tools on the floor or the bandsaw table will lead to accidents and injuries.
51Safety Rule #8If the blade comes out of the guides or breaks, stop the machine immediately by turning off the power.Do not open the access door to the machine until the wheels have come to a complete stop.Have the instructor reposition or install a new blade.