In this post, we will focus on the basics of datum and tolerance selection.

This post will discuss datum target, how to specify datum target and how to stabilise or fixture complex and/or flexible parts (such as sheet metal, warped or welded part, rough casting/moulded and forging) with datum target.

This post discusses the basic principles of datum in geometric dimensioning and tolerancing (GD&T)

In this post, we will discuss how to control wall thickness on our part design

In this post, we will discuss the effect of setup (datum) changes from design drawing to manufacturing process drawing on the total tolerance stack-up of part assemblies.

In this post, we will discuss two main types of mechanical fastener: floating and fixed fasteners as well as projected tolerance zone to control the geometrical variations of fixed fasteners.

In this post, we will discuss and understand the concept of GO and NOGO gage to verify geometric tolerance of positions and be able to design these types of gaging system.

In this post, we will go to basic and discuss the two fundamental rules of GD&T: Rule #1 and Rule #2.

In this post, we will discuss why we need to consider manufacturing processes when selecting symbols of geometrical dimensioning and tolerancing (GD&T) and assigning values of each GD&T symbol on a mechanical drawing.

In a car factory, when they want to change the gap between an engine hood and side fender within few or less mm, this change will cost thousands or even much more of dollars to the factory.

Sending satellites to space requires a launcher that can defy the gravity of earth and put the satellites into their orbits in space outside the earth’s gravity region. This post briefly presents the application of GD&T (from manufacturing discipline) to space applications.

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?