FeaturesMechTol is used to manage and analyze dimension loops.
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Design Synthesis
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The magnetic
bearing rotor is attached to the end of the shaft. None of the parts
have been dimensioned yet. Critical clearances are noted sequentially
and identified with numbers boxed by hex symbols. A possible loop scheme for analysis one (1) is shown in the figure below. |
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| The loop sequence numbers are circled while the analysis region is numerically identified and tagged with a hex. Directions of travel are indicated with single arrows on the dimension lines. Master dimension numbers have been tagged with boxes. This is the first loop so the master dimension numbers are, coincidentally, the same as the loop sequence numbers. The master dimensions have been transferred to the second full-sized layout as shown in the figure below. | ||||||||
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It is very
important to recognize that the master dimension list will consist of
fewer dimensions than the sum total of dimensions used in the loops. In
other words, some of the dimensions will be used several times.
Traditionally, this is what makes mechanical machine designers reluctant
to change dimensions on drawings. Continue with the process of defining the loops for the remaining analysis regions. Add master dimensions only when a new dimension is used. The figure below illustrates the loop setup for analysis region two (2). Note that all dimensions used in this analysis have been used previously except for one. |
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| Loop sequence numbers are shown along with travel directions. Boxed master dimension references are not, in this case, the same as the loop sequence numbers. The new dimension used in loop two is boxed six (6). The master dimension layout has been updated, as shown in the figure below, to include the new dimension. | ||||||||
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| Continue in this fashion until all
analysis regions have been defined. When the loop and master dimension
sheets have been completed you are ready to enter the data into MechTol,
perform the analysis and optimize the tolerances.
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NOTE: Analysis results yield a number which can be either positive or negative. Be sure to start your loops on the left side of your clearance gap. Starting on the left side of the gap ensures that positive results indicate a clearance and negative results indicate an interference. |
