In this post, the challenge of applying geometrical dimensioning and tolerancing (GD&T) on additive manufactured (AM) or 3D printed parts will be discussed.

The assembly feature design and tolerance stack-up analysis of aerospace parts are very important for the analysis of assembly variations or deviations.

For non-rigid part assembly, the fixturing force will be relevant and needs to be considered carefully in their assembly design.

Tolerance stack-up analysis has many advantages, especially from economical perspective.

This post will show general advantages if we have the tolerance stack-up model or the variation transformation chain of an assembly.

Assembly process should be carefully designed just as designing parts. A good design of assembly process will lead to a flexible, accurate and low-cost assembly process.

BMW reduces their total assembly cost by significantly reducing, if not completely eliminating, fixtures for assembly.

This post explains some fundamental elements of GD&T. The elements are datum reference (datum reference frame), tolerance zone and material condition.

This post presents and discusses real examples on how to interpret GD&T tolerancing symbols from technical drawings.

In this post, 3D tolerance stack-up analysis will be explained with two examples. Both traditional “+/-” dimensional tolerance and geometrical tolerance (GD&T) are considered.

Every part constituting an assembled product has tolerances assigned to the part’s features. These assigned tolerances cause variations on the key characteristics (KCs) of the assembled part. How can we know how much the variations on the KCs before manufacturing the parts?

Fixturing system has a very important role in assembly processes. Despite the complexity of fixturing systems, there are four main roles that fixturing systems should have. The four roles are locating, clamping, supporting and guiding parts during assembly processes.

Assembly is the final step to make a product in its complete form. However, no matter how complex the geometry of a part is, the part’s assembly features are boiled down to two fundamental types: mate and contact features.

Assembly processes are “the moment of truth”. There is none other better phrase to describe assembly processes than the phrase.

Any manufacturing processes will always produce parts that have some degree of deviations (errors) from the parts’ nominal design.