• 1-888-TEC-EASE
  • Outside USA: 1-716-785-6015
Free Tec-Ease Mug GD&T Textbooks GD&T Training GD&T Public Seminars GD&T Computer Based Training GD&T Reference Material
An Extruded Feature as a Datum Feature Constrains 2 Translations and 3 Rotations
(In accordance with the ASME Y14.5-2009 standard)

PDF of this Tip

There is a new chart in the ASME Y14.5-2009 standard that shows the degrees of freedom that are constrained when the feature is a primary datum feature and, where appropriate, applies RMB. The chart also shows the relationship between the feature type, simulator and theoretical datum(s) that are established. This series of six Tips illustrate the features shown in the chart. Although some of the simulators are illustrated as physical inspection equipment, these simulators may also be simulated by "soft gaging" optical or probing methods.

Linear Extruded Shape

A linear extruded shape may be a single feature as is illustrated here or a pattern of features such as a pattern of parallel holes. A linear extruded shape may arrest up to 5 degrees of freedom.

Don’t let the name fool you. This type of feature may be made by any process. It is not necessarily an extrusion. A linear extruded shape constrains 5 degrees of freedom − 3 rotations and 2 translations.

Here a pair of parallel holes is serving as datum feature A. The pattern of two parallel holes is an extruded feature and as a primary datum feature constrains 5 degrees of freedom.

Back to Tips Tip added Mar 2010