Metal Cutting

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Metal Cutting

• Plasma
• Oxy Fuel
• Band Saw
• Sawz-All
• Portable Disk (Angle) Grinder

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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

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CNC PAC

• CNC http//www.youtube.com/watch?vXARu4bLXZnM

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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.

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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 25,000F
• Most plasma cutters require at least 70 PSI

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Advantages of PAC

• Can cut ANY metal
• Torch cant 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)

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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

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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

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Setting the PAC Torch
Thickness Current Travel Speed
1/16 35 amps 175 in/min
1/8 40 amps 90 in/min
1/4 40 amps 40 in/min
1/4 80 amps 100 in/min
3/8 40 amps 18 in/min
3/8 80 amps 55 in/min
1/2 40 amps 20 in/min
1/2 80 amps 35 in/min
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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

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Cutting Jigs

• Clamp angle iron in place for straight cuts!

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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

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Dross

• Most will chip away
• Increases with slow travel speeds

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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.
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Oxy-Fuel Cutting
LINK
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Oxy Torpedo
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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.

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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.

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Oxy-Acetylene Torch Setup
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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

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OFC Equipment
Combination Cutting Torch
Straight Cutting Torch - Cant convert for
welding or brazing -
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Torch Tip

• Standard flame exits through outer ring.
• Oxygen blasts through center orifice

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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
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Neutral Flame

• Look for a defined blue cone

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OFC Cutting Tip Information
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Cutting Quality Grain Pattern
Quality Cut
Extremely Fast
Extremely Slow
Irregular Pressure
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Bending Metal

• Metal ductility increases with heat.
• Easier to bend and form.

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Hardening Metal

• Different steels have different methods
• Heat steel to ignition temp. (1300-1400F)
• 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!

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Temperature Indicating (Heat) Sticks

• Identifies the temperature of metal
• Different sticks melt at different temperatures.
• Preheating metal before welding

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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

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Horizontal Band Saw (Metal)
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Horizontal Band Saw
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Types of Blades
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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

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Blade Tension

• Blade will seize in work piece if too lose.
• Blade may snap if too tight.
• Tool of choice for long cuts

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Guide Adjustment

• Tool of choice for long cuts
• Adjust guides to ensure a straight cut.
• Blade will wonder on long cuts.

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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

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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

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Vertical Band Saw Safety Rules
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Safety Rule 1

• Keep all guards in place.

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Safety Rule 2

• Adjust the blade guards to within 1/8 to ¼ of
  the stock.

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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.

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Safety Rule 3

• Maintain the stock flat on the table.

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Safety Rule 3 - Continued

• Never hold the stock above the table, the
  material must remain flat on the table surface at
  all times.

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Safety Rule 4

• Dont 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.

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Safety Rule 5

• Concentrate your attention on the job at hand.

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Safety Rule 5 - Continued

• Do not interrupt others while using power
  equipment.
• Stay focused until the blade has stopped moving.

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Safety Rule 6

• Never leave the machine operating while
  unattended.

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Safety Rule 7

• Keep the work area clean.

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Safety Rule 7 - Continued

• Scrap wood or tools on the floor or the bandsaw
  table will lead to accidents and injuries.

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Safety Rule 8

• If 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.

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Safety Rule 9

• Do not reach across the saw line.

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Safety Rule 10

• Never back material out of a cut until power has
  been turned off and the motion of the blade has
  stopped.

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Safety Rule 11

• Always use a push stick when sawing small stock.

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Safety Rule 12

• Do not hold the stock in line with the saw blade.

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Safety Rule 12 - Continued

• Hold the stock to the sides of the cutting line.

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Safety Rule 13

• Keep your hands and fingers several inches from
  the side of the blade.

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Safety Rule 13 - Continued

• Remember to keep your hands clear of the table
  insert.

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Safety Rule 14

• Use relief cuts on tight curves to avoid
  breaking the blade.

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Chop Saw

• Manually cuts metal with a fiber composite saw
  blade.
• Cut angles
• Link

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Safety Rules

• Always wear safety glasses
• Inspect wheel before each use
• Clamp all metal before cutting, adjust if
  necessary
• Support tail of stock with blocks

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Safety Rules

• Watch where sparks are aimed
• Let cutting wheel do the work
• Do not cut pieces less than 6 inches.

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Blades

• Inspect blade before each use.
• Chips, cracks, etc.
• Remove blade when it reaches ½ of its original
  diameter.
• Do not over tighten blade

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Cutting Angle Iron

• Make sure the peak is facing UP

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Cutting Flat Bar Stock

• Width of bar should be vertical.

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Cutting Channel Iron

• Base of material should point up

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Reciprocating Saw (Sawz-All)
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Blades

• Always use the right blade for the job.
• Unplug the tool before making adjustments.
• Dont carry the saw by the cord.
• The blades get HOT!

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Safety

• Always rest the heel on the work piece.
• Prevents binding kickback

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Blades

• Applications are identified by labels on the
  packaging and blade.
• Most Common
• Wood
• Metal
• Multi-purpose

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More Blades
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Hand Tools

• Tin Snips
• Aviation Snips
• Scribers
• Steel Blue
• Soap Stone
• Paint Markers

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Tin Snips
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Aviation Snips

• Left, Straight, Right

Red should cut Right, but it doesnt.
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Layout Tools

• Scribe
• Scratch-Awls

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Layout Fluid

• Fast drying ink
• Scribing or punching
• Magnifies marks
• Remove with steel wool or alcohol

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Identification Tools

• Soap Stone
• Paint Marker

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Stamping

• Stamp your initials on projects or pieces
• ONE blunt hit with a hammer
• Solid surface

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Summary

• Follow the safety rules.
• Use the laboratory tools only for their intended
  purpose.
• Follow the directions and safety guidelines as
  listed by the machines manufacturer.
• ASK QUESTIONS!!!!