CAM2 Measure X1 adjusts measurements to the current part temperature entered. A nominal temperature of 20°C (68°F) is used. The ability to scale for temperature allows you to measure parts in areas that are either warmer or cooler. The measurement results are adjusted for thermal expansion or contraction.
To scale for material temperature changes:
1. Go to Review Features > Highlight Device Position > Click EDIT > Select Material Temperature.
2. Enter the temperature of the part, and select Celsius or Fahrenheit from the drop-down arrow.
3. Click the drop-down arrow and select a material from the library of materials. You will see the coefficient of linear expansion value change in the grayed-out box. You can see this value, but cannot change it.
4. If the material you are using is not available in the Material Library, and you know the coefficient of linear expansion of the material you are using, click the Coefficient of Linear Expansion radio button to enter the value.
5. Enter the Material Temperature of the part and click Ok to return to the Select Drawing Units dialog box. Click Ok again and begin measuring.
The temperature does not need to be set for probe calibration. There are temperature sensors in the arm that will compensate for the contraction/expansion of the arm. The arm will always measure the part at its actual size regardless of the temperature (in the 10 to 40 C range of the arm). The temperature compensation in CAM2 is used to address the contraction/expansion of the part since it will measure larger than design if it's hot and smaller than design if it is cold.
Temperature compensation for measurements should be set in the Device Position (if used). It is also part of the Alignment process, but doesn't work as effectively if you have multiple Move Device commands. If you set the temperature to 2000 C and measure a 20 mm hole it will modify the XYZ location and shrink the diameter by a factor of the expansion coefficient and the temperature difference (2000 C to 20 C). It should not affect the CAD model, only the measurements and constructions. If the temperature compensation is changing the CAD then it's a bug. The nominal data should never change.
Temperature compensation should be used when the part is very large and the tolerances are tight (i.e. most laser tracker applications). With a
FaroArm the temperature probably won't affect the part enough to make much of a difference.
Keywords: material compensation, temperature compensation, material temperature