Mirror Opposite Parts supported by Family Tables

Date:

7 November 96 - Rev3
24 September 96 - Rev2

Originated by:

Bev Sugarbaker, Steelcase Inc.
Phillip Pidgeon, OTIS Elevators.

Introduction:

Many Industries create parts and assemblies that require as drawn

("as-shown") and mirrored versions ("opposites") in order to meet handed product requirements. Often these parts are not simply complete mirrors of the original with completely different part numbers but contain the same parts used symmetrically combined with opposite parts with different partnumbers.

Problem Statement:

We create parts and show them on drawings "as shown".

We define by way of a table on the drawing an "opposite" version of the part and give it a different partno.

We would like to be able to create opposites of our parts automatically and include them in a family table as an instance.

Additionally we would like to replace or interchange as-shown and opposite parts in assemblies manually and automatically by specifying their component names in a assembly family table.

Vision:

Without changing any of the existing functionality, add the ability of a mirror all ge- ometry feature in part and sheetmetal mode that would behave similar to the COM- PONENT, CREATE PART, MIRROR command in assembly mode.

Instead of COMPONENT, CREATE, PART, (name), MIRROR part (in assembly mode), the new command could be CREATE MIRROR (in both part and sheetmet- al mode), SETUP PLANE/MAKE DATUM.

All previous features, would be "transformed" by mirroring them about the user specified datum plane to create the 'opposite' part." In a sheetmetal part the flat pattern feature would still remain the last feature (as this could be placed after the mirror feature for mirrored flat-patterns).

The new mirror feature (merge) and the flat pattern, could then be included in the part/sheetmetal family table and independently be present or suppressed.

The transformed opposite part would be dependent to the original unmirrored part. Revisions could be made by picking the resulting model with or without the mirror feature being applied.

When modifying dimensions on the model in part, sheetmetal, assembly and showing and creating dimensions in drawing mode, dimensions of the "opposite" part, should be located correctly on the mirrored model. All text should be correctly oriented.

Now that "opposite" parts are in a family table they should then be interchangeable with their "as-showns".

This would require some special attention.

The references used to assemble swappable "as shown" part should be such that the wazzu interchange with its opposite be seamless. ie all the opposite's referenc- es are equivalent to the as shown. Surface ids would either need to remain the same or have some mapping that allows the swapping/interchange of handed parts in assemblies.

This would involve datum plane's color directions being flipped, mates changing to aligns or visa versa and maybe dimensions becoming negative.

By building a family table of the assembly and including the generic's "as shown" components, instances of the assembly could be added to the assembly family ta- ble, that replaced the generic "as showns" with their "opposite" instances names producing automatic opposite assemblies.

Features unique to an instance should be able to be created in an instance (family table would show the feature as suppressed in the other instances and generic). If the unique feature(s) are created in the generic, the features should be able to be added to the family table and suppressed in any or all instances.

This would be a real asset in improving productivity and checking of symmetrical assemblies.

Observations:

There are a few ways to produce this a mirrored part at present.
    1. Create the required as shown part.
    2. Create a datum about which the part is symmetrical
    3. Mirror all the part geometry about the datum
    4. Create a solid cut that cuts away all the as shown geometry
    5. Place the datum and the cut in a family table
    6. For the as-shown version suppress the datum and the cut
    7. For the opposite version keep the datum and the cut
    8. For the flat pattern part add the flat pattern feature to the family table and suppress it for the formed up part, include it for the flatpattern of the as shown and mirrored part flatpatterns.
    1. Create the required as shown part.
    2. Create a datum about which the part is symmetrical
    3. Copy, Mirror, all feature, dependent the part geometry about the datum.
    4. Create a cut that cuts away all the as shown geometry
    5. Place the datum and the cut in a family table
    6. For the as-shown version suppress the datum and the cut
    7. For the opposite version keep the datum and the cut

    Disadvantages, with these methods are:

    1. Mirrored features are not the original features, therefore the parts are not interchangeable with their opposite references.
    2. Difficult to manage, changes to the part, as mirror geometry references change with new as shown features.
    3. References in assemblies are continually missing after changes.
    4. Dimensions show only to original part not the mirrored one.
    5. Very difficult to build assemblies from family tables given the above limitations.
    1. By Adding the part to an assembly.
    2. Mirroring the part in the assembly and giving it a new name
    3. Deleting the dummy assembly.
    Disadvantages to this method:
    1. The part is not an instance, therefore not automatically interchangeable.
    2. The part references are completely different
    3. Assemblies need to be built separately, one as shown, one opposite.