Metal Cutting

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

Plasma Arc Cutting (PAC)

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Cutting process that uses an arc and a high velocity, ionized gas coming through a small nozzle to cut ALL metals

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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 be used filter shield should  Need proper ventilation to remove harmful fumes  Do not allow Pilot Arc to continue for long periods of time

Setting the PAC Torch

Thickness

1/16” 1/8” 1/4” 1/4” 3/8” 3/8” 1/2” 1/2”

Current

35 amps 40 amps 40 amps 80 amps 40 amps 80 amps 40 amps 80 amps

Travel Speed

175 in/min 90 in/min 40 in/min 100 in/min 18 in/min 55 in/min 20 in/min 35 in/min

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 Torpedo

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

1300-1400 ° F red,  Oxygen burns preheated metal and blows it away from the work piece.

Oxy-Acetylene Torch Setup

Oxy-Fuel Cutting Process

 Oxygen (green) 20-23lbs 7lbs  | Acetylene (Red) 5-

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

OFC Cutting Tip Information

CUTTING TIP SELECTION CHART Thickness of Metal in Inches Light gauge to 3/16 3/16 - 3/8 3/8 - 5/8 5/8-1 1-2 2-3 3-6 Tip Size Number

000 00 0 1 2 3 4

Cutting Orifice Drill Size

#68 #64 #60 #56 #52 #48 #42

Oxygen Pressure Pressure Consumption Consumption (P.S.I.G.)

15-20 20-25 35-40 35-40 40-45 45-50 50-75

Acetylene (P.S.I.G.)

5-15 5-15 5-15 5-15 5-15 5-15 10-15

Oxygen (SCFH)

35-40 45-50 75-85 97-107 180-195 270-290 450-600

Acetylene (SCFH)

10-15 10-15 15-20 15-20 20-30 20-35 25-40

Cutting Quality – Grain Pattern

Quality Cut Irregular Pressure Extremely Fast 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

Horizontal Band Saw (Metal)

Horizontal Band Saw

Types of Blades

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 Turn on saw

close

as possible Slowly open gravity feed (use proper force) Lubricate with cutting oil Clean saw when finished

Vertical Band Saw Safety Rules

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

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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

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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.

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The round stock may roll into the blade causing an accident.

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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

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Do not interrupt others while using power equipment.

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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

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

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.

Safety Rule #9

 Do not reach across the saw line.

Safety Rule #10

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

Safety Rule #11

 Always use a push stick when sawing small stock.

Safety Rule #12

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

Safety Rule #12 - Continued

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Hold the stock to the sides of the cutting line.

Safety Rule #13

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

Safety Rule #13 - Continued

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Remember to keep your hands clear of the table insert.

Safety Rule #14

 Use ‘relief cuts’ on tight curves to avoid breaking the blade.

Chop Saw

 Manually cuts metal with a fiber composite saw blade.

 Cut angles Link:

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

Safety Rules

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

Blades

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

Cutting Angle Iron

Make sure the peak is facing UP

Cutting Flat Bar Stock

 Width of bar should be vertical.

Cutting Channel Iron

 Base of material should point up

Reciprocating Saw (Sawz-All)

Blades

   

Always use the right blade for the job. Unplug the tool before making adjustments.

Don’t carry the saw by the cord. The blades get HOT!

Safety



Always rest the heel on the work piece.

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Prevents binding & kickback

Blades

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

More Blades

Hand Tools

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

Tin Snips

Aviation Snips

 Left, Straight, Right

Red should cut R ight, but it doesn’t.

Layout Tools

 Scribe  Scratch-Awls

Layout Fluid

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

Identification Tools

 Soap Stone  Paint Marker

Stamping

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

Summary

 Follow the safety rules.

 Use the laboratory tools only for their intended purpose.

 Follow the directions and safety guidelines as listed by the machine’s manufacturer.

 ASK QUESTIONS!!!!