MEC322 Exam Questions And
Answers Practice Questions with
Solutions Newest | Already Graded A+
Tolerance - Answer- Total amount a dimension can be varied.
Unilateral vs. Bilateral Tolerance - Answer- Bilateral - variation can be both positive and
negative
Unilateral - variation in only one direction
3 Types of Part Fitting - Answer- Clearance - Allows for rotation and sliding between
parts
Interference - External fit of one part is larger than internal fit of other part
Transition - Small clearance or interference that allows for accurate location of mating
parts
Difference Between Accuracy and Precision - Answer- Accuracy - Closeness between
measurements and standards
Precision - Closeness between all measurements made
Inspections by Variables vs. Attributes - Answer- Variables - measured by appropriate
measuring instruments
Attributes - part dimensions are 'gauged' to determine if they are within tolerance
Acceptance Sampling - Answer- Where a product is received and compared to a
desired product.
Two Types of Limit Gage - Answer- GO - Check dimension at highest material condition
(smallest hole)
NO GO - Check dimension at lowest material (larger hole)
Stylus Instrument - Answer- Contact or non-contact tip that is used to measure the
surface
Types of CMM Probes - Answer- Fixed - solid piece of material
Touch-trigger - sends electrical signal to CMM when probe touches material
, Optical - use light to measure surface distance
Scanning Lasers - Answer- Where a laser beam is deflected by a rotating mirror to
'sweep' beam of light past an object
Machine Vision - Answer- Where image information is received, processed and
interpreted by a computer
Expendable Molds - Answer- Must be destroyed to remove casting
Permanent Molds - Answer- Can be used over and over for many castings
Cope & Drag (casting terms) - Answer- Cope - upper half of mold
Drag - lower half
Flask (casting term) - Answer- Box that the mold is contained in
Pattern (casting term) - Answer- Shape of the part
Forming Mold Cavity - Answer- Packing sand around a pattern that has shape of part.
Parts of a Gating System (casting) - Answer- Consists of a pouring cup, a downsprue
and a runner leading into the main cavity.
Why is a mold cavity oversized? - Answer- To allow for shrinkage of metal during
solidification
Core (casting term) - Answer- Creates interior shape of mold
Riser (casting term) - Answer- Contains liquid to compensate for shrinkage; designed to
freeze after the main casting (which should make sense...)
Draft (casting term) - Answer- A taper (reduced thickness) that allows the casting to be
removed from the mold
Factors that affect the pouring of metal - Answer- 1. Pouring temperature
2. Pouring rate
3. Turbulence (large changes in pressure/velocity that can create mold and accelerate
formation of oxides)
What happens when pure metal is solidified? - Answer- -Thin skin of solid metal is
formed immediately after pouring
-Skin thickness increases to form a shell around the molten metal
-Rate of freezing depends on heat transfer
Answers Practice Questions with
Solutions Newest | Already Graded A+
Tolerance - Answer- Total amount a dimension can be varied.
Unilateral vs. Bilateral Tolerance - Answer- Bilateral - variation can be both positive and
negative
Unilateral - variation in only one direction
3 Types of Part Fitting - Answer- Clearance - Allows for rotation and sliding between
parts
Interference - External fit of one part is larger than internal fit of other part
Transition - Small clearance or interference that allows for accurate location of mating
parts
Difference Between Accuracy and Precision - Answer- Accuracy - Closeness between
measurements and standards
Precision - Closeness between all measurements made
Inspections by Variables vs. Attributes - Answer- Variables - measured by appropriate
measuring instruments
Attributes - part dimensions are 'gauged' to determine if they are within tolerance
Acceptance Sampling - Answer- Where a product is received and compared to a
desired product.
Two Types of Limit Gage - Answer- GO - Check dimension at highest material condition
(smallest hole)
NO GO - Check dimension at lowest material (larger hole)
Stylus Instrument - Answer- Contact or non-contact tip that is used to measure the
surface
Types of CMM Probes - Answer- Fixed - solid piece of material
Touch-trigger - sends electrical signal to CMM when probe touches material
, Optical - use light to measure surface distance
Scanning Lasers - Answer- Where a laser beam is deflected by a rotating mirror to
'sweep' beam of light past an object
Machine Vision - Answer- Where image information is received, processed and
interpreted by a computer
Expendable Molds - Answer- Must be destroyed to remove casting
Permanent Molds - Answer- Can be used over and over for many castings
Cope & Drag (casting terms) - Answer- Cope - upper half of mold
Drag - lower half
Flask (casting term) - Answer- Box that the mold is contained in
Pattern (casting term) - Answer- Shape of the part
Forming Mold Cavity - Answer- Packing sand around a pattern that has shape of part.
Parts of a Gating System (casting) - Answer- Consists of a pouring cup, a downsprue
and a runner leading into the main cavity.
Why is a mold cavity oversized? - Answer- To allow for shrinkage of metal during
solidification
Core (casting term) - Answer- Creates interior shape of mold
Riser (casting term) - Answer- Contains liquid to compensate for shrinkage; designed to
freeze after the main casting (which should make sense...)
Draft (casting term) - Answer- A taper (reduced thickness) that allows the casting to be
removed from the mold
Factors that affect the pouring of metal - Answer- 1. Pouring temperature
2. Pouring rate
3. Turbulence (large changes in pressure/velocity that can create mold and accelerate
formation of oxides)
What happens when pure metal is solidified? - Answer- -Thin skin of solid metal is
formed immediately after pouring
-Skin thickness increases to form a shell around the molten metal
-Rate of freezing depends on heat transfer
