MEAM.Design - MEAM 201 - A02: Tolerance Stack


Note the three 0.116 diameter holes in the mounting block. The GD&T positional tolerance of 0.005 is simply a placeholder. Working with the heat sink, the mounting block, and nominal fasteners, complete a tolerance stack to determine an appropriate positional tolerance value for these holes. Provide enough detail to justify your conclusion.

If, in the course of your tolerance stackup, you discover that there is a possibility for fit failure, then you need to propose a solution that will guarantee a proper fit. This can be done via increasing or decreasing numerical or geometric tolerances for various features, adding in new GD&T callouts on the respective parts, or even modifying nominal dimensions. When doing so, you'll want to keep the following in mind:

1. Hitting tight tolerances is easier on some features than others. In general, exterior dimensions can be measured and cut with higher accuracy than interior dimensions, with the exception of small holes that can be reamed (though reaming requires a specialized tool, which may or may not be available).

2. Holes created using twist drills are very rarely undersized.

This assignment will be handed in at the beginning of lecture.