Shared Flashcard Set

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Advanced Machining
Manual theory MAP4
44
Other
Not Applicable
11/21/2021

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Cards

Term
What is the work piece charge and cutting tool charge on a ECM machine
Definition
Workpiece is a positive charge and Electrode is negative.
Term
What creates the conductive environment in an ECM
Definition
Electrolytic solution
Term
What is some advantages of using an ECM?
Definition
No spark or tool wear, very fast (Compared to EDM), easier than machining difficult materials, No heat affecting (Thin sections, better finish, no distortion)
Term
What is the overcut on an ECM?
Definition
.005" (Envelope)
Term
How does the ECM process work?
Definition
Pressurized electrolytic fluid and low voltage high amperage DC charge melts required metal away.
Term
What materials can be used as an electrode in ECM machines? What is used to prevent overcutting?
Definition
Graphite, Copper, brass, stainless. Electrode is insulated to prevent overcutting (.002/.003 gap)
Term
What charge is the grinding wheel in a ECG?
Definition
Negative charge.
Term
The current and flow electrolytic fluid between the wheel and work controls what?
Definition
Controls rate of removal and finish
Term
The process in an ECG removes __% of material and abrasive wipes __% often complete in one pass.
Definition
90% and 10%
Term
The positive charge in an ECG is the?
Definition
Work (Table)
Term
Reversing the polarity in an ECG will cause what?
Definition
Will scrub the abrasive wheel
Term
Why would you choose to use an ECG?
Definition
Good finish, no burrs, fast, hard material ground fast, no burning, warping, stress
Term
To use an ECG the work material must be?
Definition
Conductive
Term
Types of EDM?
Definition
Sinker, wire, small hole
Term
The cutting tool/electrode is ______ in an EDM?
Definition
a negative charge
Term
Dielectric fluid qualities?
Definition
Non conductive, insulator. also can be a fire hazard and skin irritant.
Term
Die sink electrode materials and some qualities of each?
Definition
Graphite: Rigid, wear can be an issue Copper: Good conductor, bends, not easy to machine Tungsten carbide: Very rigid, brittle, expensive
Term
What are the guides on a wire EDM made out of ?
Definition
Diamond casings.
Term
What determines cutting conditions of EDM machines? What affects finish and speed?
Definition
Current and voltage.
-More voltage: Faster, Poor finish
-Less voltage: slower, tool wear, better finish
Term
What is used in laser (light)?
Definition
Monochromatic light
Term
Laser types?
Definition
Solid, gas, liquid, and semi-conductor(C02, YAG, Ruby, Excimer-exciplex laser(Dimer))
Term
Light in lasers travel through tubes containing?
Definition
Mediums
Term
Where and how do cut start in lasers?
Definition
Cut is started with pulses in waste material and then traces outline.
Term
What is used to blow molten material away from cut?
Definition
Assist gases
Term
What types of assist gases are there?
Definition
Oxygen, Nitrogen (Stainless and aluminum), Argon (Titanium), Air (Economical)
Term
What causes a better finish on a laser?
Definition
Faster cuts
Term
What would the focal length be for a 7.5" piece of material be compared to a 1.0" thick material.
Definition
A longer focal length and wider (.007-.01)
Term
Systems used (laser) and the differences?
Definition
Fixed beam: Cutting head is stationary, table moves, bigger footprint, stable cutting head.

Moving beam: Work is stationary, cutting head moves, vibration and cutting head, focal point, and movement will affect cutting head.
Term
Medium power laser can cut?
Definition
1" mild steel, 5/8" stainless, 3/8" aluminum, 1/8" copper.
Term
Advantages of powder metalizing?
Definition
Red hardness inserts, porosity, magnetism, flexibility, hard surface
Term
Process of powder metalizing?
Definition
Mixing exact material in right order, compacting, drying (pre-sinter or sweating), sinter(Heat and pressure in protected environment)
Term
Types of thermal spraying?
Definition
Wire, powder, plasma spraying
Term
Physical bond of thermal spraying, mechanical bond?
Definition
Physical: Melting into parent material
Mechanical: Undercut parent material
Term
Prep needed for wire spraying?
Definition
Clean, rough surface (Square thread like), ends beveled, anti splatter on ends, pre-heat
Term
Powder spraying process?
Definition
Pre-heat, powder in hopper is sprayed on, reheated after to fuse to substrate
Term
Plasma spraying is suitable for spraying?
Definition
zirconia, tungsten, alumina, tantalum, carbide, carbide, copper.
Term
Inert gas protects environment, raises temps to ____ to _____ to melt additive (6500 to 11000) (In reference to plasma spraying)
Definition
Term
Gun drilling definition?
Definition
Drilling long (Deep) small diameter holes (300x diam)
Term
How many cutting edges on gun drills?
Definition
One cutting edge with 2 bearing supports
Term
What is needed to trepan?
Definition
Starting groove or guide bushing
Term
Advantage of trepanning?
Definition
Fast MMR and leaves you with core of material
Term
What is used to cut in water jet cutting (AWC)
Definition
Garnet is used to cut the material.
Term
How thick of mild steel can AWC cut? Stainless?
Definition
Both up to 8"
Term
Why would you want to use portable machining equipment?
Definition
Can take machine to worksite.
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