Simultaneous Requirements

A simultaneous requirement is where two or more geometric tolerances apply as a single pattern or part requirement. Within SA, Position and Profile checks using a common Datum Reference Frame (DRF) can be evaluated simultaneously if so desired. This evaluation method is a specified method within the ASME standard (see section 4.19 in the 2009 standard) and can be more true to real life in that it more directly replicates part assembly limitations. It also offers a means to add additional separate annotations to the part while still evaluating them as a unit.

 

SA Development History

 

Simultaneous Enforcement Within an SA Job File.

While stipulated by the ASME standard as a default, simultaneous evaluations are not required in ISO and are not therefore, not enabled by default in SA. Additionally, this requirement doesn't work well with real-time inspection as all of the check must be evaluated first prior to returning a result for any one check. Therefore, in many chases its best to inspect each check individually and then perform a final full evaluation using this option prior to final report generation.

 

Setting this Mode as Default

However, this option can be enabled within the GD&T Options is a check box to Force Simultaneous Evaluations within a job file automatically. When this is enabled all eligible checks will be evaluated together any time a single check is evaluated.

For checks to be evaluated together:

For feature check to be evaluated together they all need to be measured and properly configured. If any one check in a datum configuration is not measured or has a problem in its configuration then the group will not be evaluated and the problem check or checks will be reported in the report bar.

Use the Activate / Deactivate Feature check option to temperamentally exclude a feature checks from the evaluation process and allow the rest of the group to be evaluated without it: 

Checks can be excluded prior to evaluation and set to be evaluated independently as well. This can be done from the Annotation by adding the text SEP REQT to the Annotation properties in the TextBelow field. Supported text strings include: "SEPT REQT", "SEP REQT","INDIVIDUAL", "SEPARATE", "INDEPENDENT"

 

Manually Triggering a Simultaneous Evaluations

To use a simultaneous evaluation (when the default is off), right-click on one of the feature check in the list, and select Inspection> Simultaneous Evaluation. This will trigger an evaluation for the checks with that selected datum reference frame configuration.

Once evaluated the check results will then be locked such that each check result can be independently viewed without forcing a re-computation. They will also be marked as such in the Datum and Tolerance Summary Table.

 

In order to reevaluate these checks the results will need to be cleared by right-clicking on the Feature Check Category in the tree and selecting Clear All Results, or by using the Clear All button in the ribbon menu.

 

Selective Evaluations

The Simultaneously Evaluate Selected Checks option, available both in the feature check category header and GD&T ribbon menu, offers a means to use an F2 selection method to evaluate only the desired checks:

This mode is a little different in that it will handle the selected checks in isolation. This is similar to adding the "Sep Reqt" text to any checks that are not selected. All of the selected checks will be evaluated in groups based on their datum reference frames. The results will then be locked and an event created in the tree to report the results of the evaluation and list the checks that were evaluated.

An added feature is that the Simultaneous Feature Check Events offer an option in the right-click menu to Re-evaluate the selected checks again by selecting the Evaluate Simultaneous Evaluation option .