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Simultaneously Evaluating Feature Control Frames

The Insert | Dimension | Simultaneous Evaluation
menu item lets you create a Simultaneous Evaluation command inside your part program. This command evaluates two or more true position Feature Control Frames (FCFs) or two or more profile (line or surface) FCFs simultaneously.

Example: If you have two sets of holes on a part, and the holes of one set are a different size than the holes of the other set, but you want to evaluate the true position of all the holes as if they were all one set, you can use the Simultaneous Evaluation command. First, create two separate true position FCFs, one for each set of holes. Then create a Simultaneous Evaluation command to evaluate both FCFs together.

The Simultaneous Evaluation menu item displays the Simultaneous Evaluation dialog box.

Simultaneous Evaluation dialog box

The right-hand list shows all the Feature Control Frame (FCF) commands available for the Simultaneous Evaluation command. It only lists FCFs for true position or profile dimensions. Select items in the right-hand list that you want to include in the Simultaneous Evaluation command. As you select items, the Add button becomes active. You can select multiple items by holding down the CTRL key while selecting the items. Click the Clear button to deselect any highlighted items.

Click the Add button to add the selected items to the left-hand list in the Feature Control Frames area. The left-hand list defines the FCFs that will be evaluated by the Simultaneous Evaluation command.

When you have added items to the left-hand list, you can remove them from this list by selecting the items in the left-hand list and clicking Delete. This removes items from the left-hand list and re-displays them in the right-hand list. When you have added at least two FCFs to the left-hand list, the Create button becomes active. Click Create to create the Simultaneous Evaluation command and insert it into the Edit window. In the Command mode, it looks something like this:

SIMUL1 =SIMULTANEOUS/FCF2,FCF3,FCF4,,

Rules of Simultaneous Evaluation:

- The FCFs you evaluate must all be the same dimension type. They must all be true position dimensions or all surface profile dimensions or all line profile dimensions. Simultaneous evaluation does not work with orientation dimensions. If you add FCFs of differing types of dimensions to the left-hand list, when you click Create, PC-DMIS will display an error message informing you that your FCFs should all be the same type.

- All the FCFs you evaluate must have dimensions that reference the same datums in the same order of precedence. If you add two true position FCFs to the left-hand list that use different datums, when you click Create PC-DMIS will display an error message informing you that your FCFs must reference the same datums and use the same precedence.

- All the datums used must have the same material conditions. If the datums are the same, but there are different material conditions on the datums, when you click Create, PC-DMIS will display an error message informing you that you should use the same material conditions.

SIM REQT for Composite Position or Composite Profile FCFs Is Not Currently Supported

For composite position or composite profile FCFs, the lower segments are not evaluated simultaneously. This is in accordance with the default condition for ASME Y14.5 Simultaneous evaluation (both 1994 and 2009). According to the Y14.5 standard for simultaneous evaluation of composite callouts, the user must explicitly put SIM REQT next to the lower segments on the composite callouts if the lower segments are to be evaluated simultaneously. However, PC-DMIS does not currently support SIM REQT for the lower segments.

Reporting a Profile Simultaneous Evaluation:

In PC-DMIS 2009 MR1 and later, the reporting of multiple scans with profile FCFs at different tolerances evaluated simultaneously has been enhanced so that the tolerances for individual FCFs are shown in the report. For example, in the image below, the simultaneous evaluation of three profile FCF dimensions (PRF1, PRF2, and PRF3) will appear like this:

Sample Text Report Showing Tolerances of Three Profile FCFs

If you want to see the graphical analysis of these three profile FCFs in the report, you can create an ANALYSISVIEW command which references the Simultaneous Evaluation command, as shown in these sample command lines:

SIMUL1 =SIMULTANEOUS/PROF1,PROF2,PROF3,,

ANALYSISVIEW/SIMUL1,,

The graphical analysis will then display in the Report window:

Sample Graphical Analysis of a Simultaneous Evaluation Command of Three Profile FCFs