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Quiz
Try this self-administered test of your knowledge of Temperature Compensation (just 12 questions). It's OK, no-one gets to know how you score unless you tell them!
Over the typical maximum range of temperatures experienced on the shop floor (say, 50° F to 140° F, or 10° C to 60° C) Coefficients of Expansion (COE) for the most commonly machined metals are practically linear. However, COEs are typically expressed in handbooks only to within +/- 10% or so, because of uncertainties. Can you associate the following approximate COEs (expressed in parts per million per ° F or "ppm/°F") with their respective metals?
1) The approximate COE of Steel is:
- 12.2 ppm/°F
- 6.5 ppm/°F
- 10.0 ppm/°F
- 5.5 ppm/°F
2) The approximate COE of Aluminum is:
- 12.2 ppm/°F
- 6.5 ppm/°F
- 10.0 ppm/°F
- 5.5 ppm/°F
3) The approximate COE of powdered metals is:
- 12.2 ppm/°F
- 6.5 ppm/°F
- 10.0 ppm/°F
- 5.5 ppm/°F
4) What
is the standard international reference temperature at which all measurements
are specified, as stipulated by ISO and ANSI?
- 32° F (0° C)
- 50° F (10° C)
- 68° F (20° C)
- 86° F (30° C)
5) What
is the difference between an "accurate" and a "precise" gaging system?
- a precise gage has greater resolution than an accurate gage
- a precise gage has better R & R than an accurate gage
- there is no difference
- an accurate gage gives results which are closest to true dimension, while a precise gage is repeatable, even if inaccurate.
6) Which "elements" of a measurement system (gage) can contribute to temperature induced error? A good example of such a system can be found here.
- workpiece
- gage fixture
- setting master
- all of the above
7) How
large a dimensional variation will be observed in a three (3) inch (76 mm)
aluminum component as a result of it changing temperature by 20°
F / 11° C, say from 65° F
/ 18° C to 85° F / 29°
C? - Calculators allowed. (Clue: coefficient of expansion for aluminum is the
answer to question 3.) A good example of such a part is an auto engine piston.
See our
Application Note on temperature compensating piston gages.
- .0004 in / 0.010 mm
- .0006 in / 0.015 mm
- .0008 in / 0.020 mm
- .0010 in / 0.025 mm
8) How
large a dimensional variation will be observed in a three (3) inch (76 mm) steel
component as a result of it changing temperature by 20°
F / 11° C, from 65° F / 18°
C to 85° F / 29° C? -
Calculators allowed. . (Clue: coefficient of expansion for steel is the answer
to question 2.)
- .0002 in / 0.005 mm
- .0003 in / 0.0075 mm
- .0004 in / 0.010 mm
- .0006 in / 0.015 mm
9) What do the letters "TEI" stand for?
- Theorized Expansion Indicator - an estimate of thermal expansion coefficient
- Thermal Error Index - an ANSI defined estimate of overall thermal error in a measurement system
- Temperature Equalization Inversion - the amount of thermal error offset experienced when setting master and gage vary in temperature by the same amount
- Thermal Energy Input - the amount of thermal energy generated in a part as a result of a production process
10) What is a Full Electronic Temperature Compensation System? Albion's TComp II system is just one of our systems in this category.
- A system of temperature sensors and an electronic controller which senses temperatures of master, workpiece and gage fixture during measuring operations and generates a real-time net correction for thermal errors
- A sensor and electronic interface which senses the temperature of parts while they are being measured
- A method by which temperature is controlled at nominal temperature
- An off line computer into which an operator punches temperatures and dimensions in order to calculate thermal errors
11) Approximately how much of the thermal error in a measurement should an Electronic Temperature Compensation System consistently eliminate?
- 80% or better
- 92% or better
- 65% or better
- 50% or better
12) What is the principal benefit of a Temperature Compensation System?
- Measurements are always given at reference temperature, regardless of actual temperatures
- The system constantly displays the temperatures of workpiece and gage during measuring operations
- A cheaper coolant can be used in metal cutting processes
- Machine operators can take the afternoon off