DIMENSIONAL ACCURACY ENG 205 CE-ME-MECE-MSE
PRECISE (adjective): Exactly the same • We were gossipping about him, and he walked in at that precise moment.
IMPRECISE (adjective): Not exactly the same, containing some error or uncertainty • Many of the problems are a result of imprecise information.
VARY (verb): to be different from something, differ • Class numbers vary between 30 to 35.
VARIATION (noun): difference • There is great variation in temperatures of day and night.
ACCURATE (adjective): exact,correct • My watch is not very accurate.
ACCURACY (noun): the condition of being exact and correct • You can trust the accuracy of this report. Five people have checked it before you.
TOLERANCE (noun):within/outside tolerance The acceptable difference in some measurement • We are working to a tolerance of 0.1mm. 5.1 mm is within tolerance, but 5.2 mm is outside tolerance.
PRECISION (noun): The quality of being exact and accurate • Precision is highly important in science.
RANGE (noun): the area of difference between upper and lower limits • Most of the university students are in the 17-25 age range.
DEVIATION (noun): difference • There is a small deviation from the original plan.
PLUS OR MINUS (preposition): Used when the number mentioned may actually be more or less a certain amount • There will be plus or minus twenty people for dinner.
DEVIATE (verb): To be different from • The bus had to deviate from its usual route because of a road closure.
INACCURATE (adjective): Not exact, correct or accurate • We got lost because the map was inaccurate.
PERMISSIBLE (adjective): Allowed, acceptable • The lab found permissible levels of phosphate in the water, so it will not cause any problems for your health.
TIGHT/CLOSE TOLERANCE (adjective+noun): A very small amount of tolerance • ± 0.01 mm is a tight tolerance.
LOOSE TOLERANCE (adjective+noun): A big amount of tolerance • ± 0.1 cm is a loose tolerance.
FIT (verb): To be the right shape and size for somebody or something • The key doesn’t fit the lock.
FIT (noun): The way that something fits • The coat is a perfect fit.
CLEARANCE(noun): Gap, space • There is not much clearance for vehicles to pass under the bridge.
INSUFFICIENT (adjective): Not enough • I think the teacher gave insufficient time for this project. We can’t finish it on time.
BIND (verb): To stick together • Will this wallpaper bind to the wall?
PLAY (verb): To move freely as machine parts do • There was too much play in the steering wheel.
INTERFERENCE (noun): The act of blocking, interrupting or preventing • In 1980, there was an interference with the democracy.
EXPAND (verb): To increase in size • Metals expand when thay are heated.
EXPANSION (noun): The act of increasing in size • There has been an expansion of higher education institutions recently.
CONTRACT (verb): To decrease in size • Pipes contract in cold weather.
CONTRACTION (noun): The act of decreasing in size • Electrical power lines look tight because of the contraction in cold weather.
Partner A: Ask the questions.Partner B: Answer the questions. • What does tolerance mean in engineering? • If you have a shaft with a diameter of 30 mm ± 0.5 mm, what is within tolerance? What is outside tolerance? • What is a tight tolerance?
Partner A: Ask the questions.Partner B: Answer the questions. • What does tolerance mean in engineering? Tolerances are acceptable variations in precision. Instead of giving one precise size, a tolerance gives a range of accebtable sizes. • If you have a shaft with a diameter of 30 mm ± 0.5 mm, what is within tolerance? What is outside tolerance? Shafts with a diameter of 29.5 to 30.5 mm are within tolerance. Less than 29.5 and more than 30.5 mm are outside tolerance. • What is a tight tolerance? A very small permissible deviation in size
Partner B: Ask the questions.Partner A: Answer the questions. • What is a loose tolerance? • What is a clearance fit? Can you give an example? • What is an interference fit? Can you give an example?
Partner B: Ask the questions.Partner A: Answer the questions. • What is a loose tolerance? A large permissible deviation in size • What is a clearance fit? Can you give an example? It allows a component to play freely by leaving clearance between itself and the sides of the hole. It is used in shafts. • What is an interference fit? Can you give an example? It is a very tight fit, and it doesn’t allow a component to move freely. It is done by forcing a component into a hole or by heating a component. It is used in train wheels.
EXERCISES & OVER TO YOU