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Composite position Tolerancing_20250116

Composite position Tolerancing_20250116

COMPOSITE POSITION

 

This document is intended to provide information on how to perform “Composite Position” tolerancing with true position. In this type of tolerancing, which tolerance values and which elements and which datums will be used should be specified in the technical drawing as shown in the example picture below.

 

In order to make “Composite Position” tolerancing, you must first create an feature group (Pattern). To do this, select “Construct” mode and click on the “Pattern” icon in the “Measure” menu.

 

 

 

 

In the window that opens, select the elements you want to tolerate and click on the “Calculate” icon marked in the picture below.

 

Then click on the “Composite Position” icon in the GDT menu and select the pattern element in the window that opens.

 

 

There are two different tolerances in this tolerancing. These are;

PLTZF (Pattern Locating Tolerance Zone Framework): This specifies the position of the pattern as a whole relative to the datum and indicates a larger position tolerance for the pattern.

FRTZF (Feature Relating Tolerance Zone Framework): It is the tolerance that provides the relationship between the features in the pattern and is a smaller position tolerance for each feature in the pattern.

To better understand the topic, please refer to the image below. The positions of the holes at the ends of the red pattern will be within tolerance as long as they are within the FRTZF zone. Similarly, the pattern will be within tolerance as long as its center is within the PLTZF zone.

 

You can see in the preview how it will look when you enter the tolerance values given in the Technical Drawing and press “Update”.

 

 

 

 

Click on “Datums” to select the datums and define the datums in the window that opens. Here, to activate the datum of the second parameter, check the “Apply” box on the right side of the window and press “Apply” at the bottom left of the window and you can see the preview marked in the picture below.

 

Then press “OK” to return to the “Composite Position” window and press “OK” in this window. In the report window, it will create a report as shown in the picture below.