MEC322 – Midterm| Ques ons and answers | Updated
RATED A+ 2026
Tolerance
Total amount a dimension can be varied.
Unilateral vs. Bilateral Tolerance
Bilateral - varia on can be both posi ve and nega ve
Unilateral - varia on in only one direc on
3 Types of Part Fi ng
Clearance - Allows for rota on and sliding between parts
Interference - External fit of one part is larger than internal fit of other part
Transi on - Small clearance or interference that allows for accurate loca on of ma ng parts
Difference Between Accuracy and Precision
Accuracy - Closeness between measurements and standards
Precision - Closeness between all measurements made
Inspec ons by Variables vs. A+ributes
Variables - measured by appropriate measuring instruments
A+ributes - part dimensions are 'gauged' to determine if they are within tolerance
Acceptance Sampling
Where a product is received and compared to a desired product.
Two Types of Limit Gage
GO - Check dimension at highest material condi on (smallest hole)
NO GO - Check dimension at lowest material (larger hole)
, Stylus Instrument
Contact or non-contact p that is used to measure the surface
Types of CMM Probes
Fixed - solid piece of material
Touch-trigger - sends electrical signal to CMM when probe touches material
Op cal - use light to measure surface distance
Scanning Lasers
Where a laser beam is deflected by a rota ng mirror to 'sweep' beam of light past an object
Machine Vision
Where image informa on is received, processed and interpreted by a computer
Expendable Molds
Must be destroyed to remove cas ng
Permanent Molds
Can be used over and over for many cas ngs
Cope & Drag (cas ng terms)
Cope - upper half of mold
Drag - lower half
Flask (cas ng term)
Box that the mold is contained in
Pa+ern (cas ng term)
Shape of the part
Forming Mold Cavity
Packing sand around a pa+ern that has shape of part.
Parts of a Ga ng System (cas ng)
Consists of a pouring cup, a downsprue and a runner leading into the main cavity.
RATED A+ 2026
Tolerance
Total amount a dimension can be varied.
Unilateral vs. Bilateral Tolerance
Bilateral - varia on can be both posi ve and nega ve
Unilateral - varia on in only one direc on
3 Types of Part Fi ng
Clearance - Allows for rota on and sliding between parts
Interference - External fit of one part is larger than internal fit of other part
Transi on - Small clearance or interference that allows for accurate loca on of ma ng parts
Difference Between Accuracy and Precision
Accuracy - Closeness between measurements and standards
Precision - Closeness between all measurements made
Inspec ons by Variables vs. A+ributes
Variables - measured by appropriate measuring instruments
A+ributes - part dimensions are 'gauged' to determine if they are within tolerance
Acceptance Sampling
Where a product is received and compared to a desired product.
Two Types of Limit Gage
GO - Check dimension at highest material condi on (smallest hole)
NO GO - Check dimension at lowest material (larger hole)
, Stylus Instrument
Contact or non-contact p that is used to measure the surface
Types of CMM Probes
Fixed - solid piece of material
Touch-trigger - sends electrical signal to CMM when probe touches material
Op cal - use light to measure surface distance
Scanning Lasers
Where a laser beam is deflected by a rota ng mirror to 'sweep' beam of light past an object
Machine Vision
Where image informa on is received, processed and interpreted by a computer
Expendable Molds
Must be destroyed to remove cas ng
Permanent Molds
Can be used over and over for many cas ngs
Cope & Drag (cas ng terms)
Cope - upper half of mold
Drag - lower half
Flask (cas ng term)
Box that the mold is contained in
Pa+ern (cas ng term)
Shape of the part
Forming Mold Cavity
Packing sand around a pa+ern that has shape of part.
Parts of a Ga ng System (cas ng)
Consists of a pouring cup, a downsprue and a runner leading into the main cavity.
