MMET 181 TEST 2 || WITH A+ GUARANTEED
SOLUTIONS.
Why is cutting fluid necessary? correct answers 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 answers water base + additives
What does lubricant consist of? correct answers oil base + additives
How do nontraditional machining processes differ from traditional machining processes? correct
answers 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 answers 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 answers Metals, ceramics, etc.
What is the difference between water and abrasive jets? correct answers 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 answers 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 answers A subtractive or reverse-plating process
when material is removed from the anode. Useful for deburring.
What is the ratio for current density? correct answers I/A or (current/electrode frontal area)
What is the ratio for machining depth? correct answers V/A or (volume of removed
material/electrode frontal area)
What is the ratio of material removal rate? correct answers V/t or (volume of removed
material/time)
What is electrical discharge machining (EDM)? correct answers 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 answers 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 answers 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 answers Material melting temperature
How do electron and ion beams work? correct answers 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 answers 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 answers 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 answers 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 answers Grinding is one form of abrasive machining. It is similar to
traditional milling but at a very small scale.
What is honing? correct answers 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
answers 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 answers 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 answers 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 answers 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 answers When an operator uses a file or scraper to remove
burrs.
What is mechanical deburring? correct answers A part is exposed to a moving wire brush,
abrasive belt, moving particles, etc., to remove burrs.
What is thermal deburring? correct answers 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 answers When a small burr is removed using the
ECM process.
What is chemical mechanical polishing? correct answers A process that combines mechanical
and chemical actions to remove materials. Produces extremely flat silicon wafers.
What is anodizing? correct answers This is another version of electroplating. Atoms from the
anodic part are removed, and the anodic surface gains oxygen and organize dues to form a hard
and colorful oxide layer to protect against corrosion as well as for a decorative finish.
What is sputtering? correct answers Surface atoms of a workpiece are removed due to the impact
from other energetic atoms. Must be in a high vacuum.
What is shot peening? correct answers A process where a workpiece is repeatedly bombarded
with high velocity particles. These high hardness spherical balls form a hardened layer on the
surface of the material with helps it resist crash initiation.
What is case hardening? correct answers Foreign atoms diffuse into the surface of a workpiece
material at a high temperature and concentration. (steel + carbon = cast iron)
What is plating? correct answers When a thin metallic layer is deposited on the surface of a
workpiece. There are two techniques:
1) Electroplating: only used with conductive materials
2)Electroless technique: does not require a conductive material since electricity is not required.
How do you increase productivity? correct answers By decreasing cost, and time, and increasing
parts.
What are two common tools to analyze manufacturing lines for productivity improvement?
correct answers 1)Motion study
2)Time study
SOLUTIONS.
Why is cutting fluid necessary? correct answers 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 answers water base + additives
What does lubricant consist of? correct answers oil base + additives
How do nontraditional machining processes differ from traditional machining processes? correct
answers 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 answers 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 answers Metals, ceramics, etc.
What is the difference between water and abrasive jets? correct answers 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 answers 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 answers A subtractive or reverse-plating process
when material is removed from the anode. Useful for deburring.
What is the ratio for current density? correct answers I/A or (current/electrode frontal area)
What is the ratio for machining depth? correct answers V/A or (volume of removed
material/electrode frontal area)
What is the ratio of material removal rate? correct answers V/t or (volume of removed
material/time)
What is electrical discharge machining (EDM)? correct answers 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 answers 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 answers 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 answers Material melting temperature
How do electron and ion beams work? correct answers 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 answers 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 answers 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 answers 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 answers Grinding is one form of abrasive machining. It is similar to
traditional milling but at a very small scale.
What is honing? correct answers 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
answers 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 answers 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 answers 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 answers 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 answers When an operator uses a file or scraper to remove
burrs.
What is mechanical deburring? correct answers A part is exposed to a moving wire brush,
abrasive belt, moving particles, etc., to remove burrs.
What is thermal deburring? correct answers 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 answers When a small burr is removed using the
ECM process.
What is chemical mechanical polishing? correct answers A process that combines mechanical
and chemical actions to remove materials. Produces extremely flat silicon wafers.
What is anodizing? correct answers This is another version of electroplating. Atoms from the
anodic part are removed, and the anodic surface gains oxygen and organize dues to form a hard
and colorful oxide layer to protect against corrosion as well as for a decorative finish.
What is sputtering? correct answers Surface atoms of a workpiece are removed due to the impact
from other energetic atoms. Must be in a high vacuum.
What is shot peening? correct answers A process where a workpiece is repeatedly bombarded
with high velocity particles. These high hardness spherical balls form a hardened layer on the
surface of the material with helps it resist crash initiation.
What is case hardening? correct answers Foreign atoms diffuse into the surface of a workpiece
material at a high temperature and concentration. (steel + carbon = cast iron)
What is plating? correct answers When a thin metallic layer is deposited on the surface of a
workpiece. There are two techniques:
1) Electroplating: only used with conductive materials
2)Electroless technique: does not require a conductive material since electricity is not required.
How do you increase productivity? correct answers By decreasing cost, and time, and increasing
parts.
What are two common tools to analyze manufacturing lines for productivity improvement?
correct answers 1)Motion study
2)Time study
