MMET 181 - Exam 2 With Questions and
Correct Answers | Latest Version |
2024/2025 | Rated A+
Why is cutting fluid necessary? - Correct Answer--Reduces tool and workpiece
temperature
Decreases cutting force and cutting power
Prolongs tool life
Improves surface finish
Flushes away chips
What does coolant consist of? - Correct Answer--water base + additives
What does lubricant consist of? - Correct Answer--oil base + additives
How do nontraditional machining processes differ from traditional machining
processes? - Correct Answer--Nontraditional machining processes use
thermal, electrical, chemical energies etc. instead of mechanical energy (like
in traditional machining processes).
How do water jets work and what can they cut through? - Correct Answer--
Water jets use a high pressurized stream of water to cut a workpiece. They
can cut plastics, leather, paper, textile, bone, etc.
What are abrasive jets used to cut? - Correct Answer--Metals, ceramics, etc.
What is the difference between water and abrasive jets? - Correct Answer--
Abrasive jets contain abrasives in the solution, meaning it can cut through
harder materials. Because of these abrasives, the regular water jet is
considered more environmentally friendly.
,What is electroplating? - Correct Answer--A process that covers a conductive
metal with another metal. The positive charge ions (protective metal) move
toward the negatively charged material (object you want to cover) due to the
attractive force of opposite charges.
What is electrochemical machining? - Correct Answer--A subtractive or
reverse-plating process when material is removed from the anode. Useful for
deburring.
What is the ratio for current density? - Correct Answer--I/A or
(current/electrode frontal area)
What is the ratio for machining depth? - Correct Answer--V/A or (volume of
removed material/electrode frontal area)
What is the ratio of material removal rate? - Correct Answer--V/t or (volume
of removed material/time)
What is electrical discharge machining (EDM)? - Correct Answer--Electrical
energy is charged and stored in a capacitor. When discharging, current flows
and creates a tiny plasma arc between the anode and cathode. Within the
plasma the ions remove the material from both electrodes. During the off-
time period, the capacitor is charged again while debris is flushed away by
the dielectric fluid.
What is die sinking (ram) EDM? - Correct Answer--A discrete and shaped
electrode is used to "sink" and copy the footprint of the electrode into a
workpiece. Fabricates dies and molds, is reusable.
What is wire EDM? - Correct Answer--A continuous wire electrode is used to
cut a slot through the thickness of a workpiece. Not reusable.
,What does the MRR of EDM solely depend on? - Correct Answer--Material
melting temperature
How do electron and ion beams work? - Correct Answer--Both positive ions
and negative electrons are collected, focused, and accelerated toward a
target. The process must take place in a vacuum.
What is a laser beam? - Correct Answer--A highly collimated optical beam
that can be focused into a very small area.
What are the common laser types, their wavelength, and applications? -
Correct Answer--Carbon Dioxide Laser: 10 micrometers, thermal, regular
machining
YAG Laser: 1 micrometer, thermal, regular machining
Excimer Laser: (slower) 0.1 micrometer, surgical/medical applications
because it does NOT dissipate heat
How does chemical etching work? - Correct Answer--Material can be
selectively removed by chemical reaction by using a maskant to cover the
areas that are not to be removed. Usually applied to thin metal sheets.
What is grinding? - Correct Answer--Grinding is one form of abrasive
machining. It is similar to traditional milling but at a very small scale.
What is honing? - Correct Answer--Honing is the grinding process that
smoothes an internal surface such as the inside diameter of a hole.
What is the difference between creep-feed grinding and conventional surface
grinding? - Correct Answer--Conventional grinding does multiple passes on
the material, while creep-feed grinding performs one single pass (at a slower
feed rate). The MRR is the same for both processes, however.
, What is lapping? - Correct Answer--Lapping uses a separate abrasive slurry
and is applicable to curved surfaces. It achieves better surface finish than
grinding. (Can look kind of like a waffle maker, where the grooves are
designed to keep lapping slurry and lapped debris).
What is polishing? - Correct Answer--A process that either removes a fine
surface or undesirable layer of material to achieve a shiny surface for
optimal application or application with low friction. Uses polishing wheel or
sheet made from special paper, leather, etc.
What is buffing? - Correct Answer--A type of polishing technique that uses a
buffing wheel bathed with an abrasive compound which rotates and levels
fine asperities on a surface. Useful for complex parts.
What is manual deburring? - Correct Answer--When an operator uses a file or
scraper to remove burrs.
What is mechanical deburring? - Correct Answer--A part is exposed to a
moving wire brush, abrasive belt, moving particles, etc., to remove burrs.
What is thermal deburring? - Correct Answer--When a high thermal energy is
applied for a very short time and a small burr melts onto the bulk workpiece.
What is electrochemical deburring? - Correct Answer--When a small burr is
removed using the ECM process.
What is chemical mechanical polishing? - Correct Answer--A process that
combines mechanical and chemical actions to remove materials. Produces
extremely flat silicon wafers.
Correct Answers | Latest Version |
2024/2025 | Rated A+
Why is cutting fluid necessary? - Correct Answer--Reduces tool and workpiece
temperature
Decreases cutting force and cutting power
Prolongs tool life
Improves surface finish
Flushes away chips
What does coolant consist of? - Correct Answer--water base + additives
What does lubricant consist of? - Correct Answer--oil base + additives
How do nontraditional machining processes differ from traditional machining
processes? - Correct Answer--Nontraditional machining processes use
thermal, electrical, chemical energies etc. instead of mechanical energy (like
in traditional machining processes).
How do water jets work and what can they cut through? - Correct Answer--
Water jets use a high pressurized stream of water to cut a workpiece. They
can cut plastics, leather, paper, textile, bone, etc.
What are abrasive jets used to cut? - Correct Answer--Metals, ceramics, etc.
What is the difference between water and abrasive jets? - Correct Answer--
Abrasive jets contain abrasives in the solution, meaning it can cut through
harder materials. Because of these abrasives, the regular water jet is
considered more environmentally friendly.
,What is electroplating? - Correct Answer--A process that covers a conductive
metal with another metal. The positive charge ions (protective metal) move
toward the negatively charged material (object you want to cover) due to the
attractive force of opposite charges.
What is electrochemical machining? - Correct Answer--A subtractive or
reverse-plating process when material is removed from the anode. Useful for
deburring.
What is the ratio for current density? - Correct Answer--I/A or
(current/electrode frontal area)
What is the ratio for machining depth? - Correct Answer--V/A or (volume of
removed material/electrode frontal area)
What is the ratio of material removal rate? - Correct Answer--V/t or (volume
of removed material/time)
What is electrical discharge machining (EDM)? - Correct Answer--Electrical
energy is charged and stored in a capacitor. When discharging, current flows
and creates a tiny plasma arc between the anode and cathode. Within the
plasma the ions remove the material from both electrodes. During the off-
time period, the capacitor is charged again while debris is flushed away by
the dielectric fluid.
What is die sinking (ram) EDM? - Correct Answer--A discrete and shaped
electrode is used to "sink" and copy the footprint of the electrode into a
workpiece. Fabricates dies and molds, is reusable.
What is wire EDM? - Correct Answer--A continuous wire electrode is used to
cut a slot through the thickness of a workpiece. Not reusable.
,What does the MRR of EDM solely depend on? - Correct Answer--Material
melting temperature
How do electron and ion beams work? - Correct Answer--Both positive ions
and negative electrons are collected, focused, and accelerated toward a
target. The process must take place in a vacuum.
What is a laser beam? - Correct Answer--A highly collimated optical beam
that can be focused into a very small area.
What are the common laser types, their wavelength, and applications? -
Correct Answer--Carbon Dioxide Laser: 10 micrometers, thermal, regular
machining
YAG Laser: 1 micrometer, thermal, regular machining
Excimer Laser: (slower) 0.1 micrometer, surgical/medical applications
because it does NOT dissipate heat
How does chemical etching work? - Correct Answer--Material can be
selectively removed by chemical reaction by using a maskant to cover the
areas that are not to be removed. Usually applied to thin metal sheets.
What is grinding? - Correct Answer--Grinding is one form of abrasive
machining. It is similar to traditional milling but at a very small scale.
What is honing? - Correct Answer--Honing is the grinding process that
smoothes an internal surface such as the inside diameter of a hole.
What is the difference between creep-feed grinding and conventional surface
grinding? - Correct Answer--Conventional grinding does multiple passes on
the material, while creep-feed grinding performs one single pass (at a slower
feed rate). The MRR is the same for both processes, however.
, What is lapping? - Correct Answer--Lapping uses a separate abrasive slurry
and is applicable to curved surfaces. It achieves better surface finish than
grinding. (Can look kind of like a waffle maker, where the grooves are
designed to keep lapping slurry and lapped debris).
What is polishing? - Correct Answer--A process that either removes a fine
surface or undesirable layer of material to achieve a shiny surface for
optimal application or application with low friction. Uses polishing wheel or
sheet made from special paper, leather, etc.
What is buffing? - Correct Answer--A type of polishing technique that uses a
buffing wheel bathed with an abrasive compound which rotates and levels
fine asperities on a surface. Useful for complex parts.
What is manual deburring? - Correct Answer--When an operator uses a file or
scraper to remove burrs.
What is mechanical deburring? - Correct Answer--A part is exposed to a
moving wire brush, abrasive belt, moving particles, etc., to remove burrs.
What is thermal deburring? - Correct Answer--When a high thermal energy is
applied for a very short time and a small burr melts onto the bulk workpiece.
What is electrochemical deburring? - Correct Answer--When a small burr is
removed using the ECM process.
What is chemical mechanical polishing? - Correct Answer--A process that
combines mechanical and chemical actions to remove materials. Produces
extremely flat silicon wafers.
