Transcript Oxy-Fuel Cutting
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 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
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.
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
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
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.
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!!!!