Creating Fixture Tolerances

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Creating Fixture Tolerances

We need to tolerance the Fixture surface points for profile and the pin points for position. We already created the size tolerance for the pin points when we defined the points as features of size.

 

Select the DVTI_tolearncelist Tolerances button then select the Fixture. The Size Tolerances are already in the Tolerance List.

Select Linear in the drop-down list then click [Add]. This will open the Linear Tolerance dialog.

 

The function of the Linear Tolerance is similar to a Profile GD&T: both tolerances vary the features in one direction. The difference is that the Linear Tolerance can specify a direction of variation while the Profile GD&T always uses the direction normal to the feature.  In this situation the Profile GD&T could have also been used to add variation to points in the Fixture, however to introduce a new tool we will use the Linear Tolerance.

 

Change the Name to "Fixture_Pad_Profile".

Enter the Description "Profile of the Fixture pads."

Set the Mode as Independent.

Click [Add] then select the points T_Fixture_X1, T_Fixture_X2, and T_Fixture_X3 in the Fixture.

Click [OK][Close] in the Pick FeatureSelect dialog.

Set the Dir. Type to AssocDir.

Set the Distribution as Normal and change the Range to 0.2 mm.

 

The completed Linear Tolerance should look like the image below.

 

L10 Linear Tolerance Dialog Complete

 

Click [OK] to save the tolerance and close the dialog.

Select Circular in the Tolerances dialog drop-down list then click [Add]. This will open the Circular Tolerance dialog.

 

The function of the Circular Tolerance is similar to the Position GD&T: both tolerances vary the features in a plane, that is to say two directions. The difference is that the Circular Tolerance can specify a direction of variation while the Position GD&T always uses the direction of the feature.  Similar to above, the Position GD&T could have also been used to add variation to pins in the Fixture, however to introduce a new tool we will use the Circular Tolerance.

 

Change the Name to "Fixture_Pin_Position".

Enter the Description "Position of the Fixture pins."

Set the Mode as Independent.

Click [Add] then select the points Fixture_YZ_Pt and Fixture_Z_Pt in the Fixture.

Click [OK][Close] in the Pick FeatureSelect dialog.

Set the material condition as MMC in the drop-down list.

Set the Dir. Type to AssocDir.

Set the Rand. Index to Rand#1.

Set the Distribution as RightSkew and change the Range to 0.2 mm.

Set the Rand. Index to Rand#2.

Set the Distribution as Uniform and set the Range as 360deg.

 

The completed Circular Tolerance should look like the image below.

 

L10 Circular Tolerance Dialog Complete

 

Click [OK] to save the tolerance and close the dialog.

Click [OK] to close the Tolerances dialog.

Save the model using Save Management.

Show the points using DVTI_dcsShowPoint Show Points if they are hidden.

Click the DVTI_dcsDeviate Deviate button to see the variation on the Fixture points.

DVTI_dcsNominalBuild_SP Nominal Build and DVTI_dcsDeviate Deviate to see the variation of the Bracket on the Fixture.

Click DVTI_dcsSeparate_SP Separate.