Inventor In-Depth: Optimized Weldment Design and Documentation

14 Jul, 2005 By: Kevin Schneider Cadalyst

Increase the accuracy of your welded assemblies

Autodesk Inventor lets you work in a weld-specific environment with functionality tailored to the unique design requirements of designing and documenting weldments. The weld environment provides the same functionality as standard assembly mode, but it has additional capabilities for creating weld beads and symbols.

To get started, assemble the base members of your weldment while working within standard assembly mode. When you're ready to add welds, click on Convert and choose Weldment to access relevant features (figure 1).

Figure 1. Choose Weldment to begin.

The Weldment environment offers functionality and a user interface specific to creating weld beads and symbols (figures 2 and 3).

Figure 2. Tools for weld-specific tasks are in the Weldment Features panel.

Figure 3. Use the weld-specific browser to organize weld features, beads and symbols.

Weld Creation
Autodesk Inventor 10 allows for several types of weld bead creation including fillet, groove and cosmetic welds. You can create any number or combination of these welds.

Fillet Welds
Autodesk Inventor 10 includes enhanced fillet weld functionality such as a Chain Select function for faster selection. You can control the aspects of your fillet welds -- size, contour and spacing -- by clicking on the Fillet Weld icon to open the Fillet Weld dialog box (figure 4).

Figure 4. Use the Fillet Weld dialog box to create and modify your weld.

Gap and Groove Welds
New to Autodesk Inventor 10, groove welds enable you to place welds between gaps in geometry. You control the placement and direction of the weld (figure 5). Choose the Full Face option to specify that the weld bead extends to consume both face sets. If face sets 1 and 2 are different lengths, the weld bead expands to fit both faces. The Ignore Internal Loops option allows a selected face set to ignore the non-outer geometric loops present on that face.

Figure 5. Use the Groove Weld dialog box to create a weld that connects two face sets with a solid weld bead.

Cosmetic Welds
Cosmetic welds allow you to specify the location and cross-sectional area of welds within your 3D model without worrying about the exact geometry they will form. They are useful when the design does not require interference analysis or the aesthetic appearance of solid weld beads. Their approximate physical properties can be included in mass properties (figure 6).

Figure 6. Choose the location and cross-sectional area of cosmetic welds.

Welding Symbols
The biggest benefit of creating welds within the 3D solid model is having the weld symbols automatically available in the associative drawing environment of Autodesk Inventor. You can create weld symbols in several ways; following are functional and best practice tips.

Creating Symbols
You can create a welding symbol at the same time you create a weld bead, or do so in a separate operation. The Welding Symbol dialog box is specific to your document's active standard (such as ANSI, ISO and DIN) in order to accommodate the many permutations in symbol documentation. If a weld bead is not associated with a weld symbol it is said to be unconsumed. It's best to associate each weld bead with a weld symbol and avoid confusion.

Grouping Weld Beads Under One Symbol
In some instances you may choose to annotate multiple welds with the same symbol. To add multiple welds beads to the same symbol, right-click on the desired weld symbol, choose Edit Welding Symbol, and add additional weld beads by selecting them in either the browser or the model window (figure 7). Conveniently, only unconsumed welds appear highlighted in the model window.

Right-clicking in the browser or model window lets you select Weld Beads and quickly see which weld beads have and have not been consumed. To dissociate a weld bead from its symbol, right-click on the bead and choose the Unconsume Bead command from the Context menu.

Figure 7. Use the fields in the Welding Symbol dialog box to associate each symbol with a specific weld bead and specify the text and layout of the weld annotation.

Documenting Welds
You can automatically add welding symbols and annotations from the 3D weldment model to a weldment drawing view when it is placed. Model weldment annotations are associated with the model and automatically get updated when the model is changed. 1. To create a welding symbol that updates simultaneously with the model welding symbol, right-click the drawing view and select Get Model Annotations / Get Welding Symbols (figure 8).
2. To create an end fill that updates with model end fills, right-click the drawing view and select Get Model Annotations / Get Weld Annotations.
3. You can also add non-associative weldment annotations to your drawings.

Figure 8. Right-click to retrieve weld symbols and annotations in a drawing.

Weld Analysis and Reporting
Autodesk Inventor includes tools for calculating and reporting weld properties. With one click you can generate an Excel spreadsheet with properties such as weld ID, type, length, mass, area and volume. You can perform comprehensive interference detection of all solid weld bead types. Your model's mass properties calculations automatically include solid weld geometry. And if desired, you can include cosmetic welds in the overall mass properties calculation (figure 9).

Figure 9. Choose to include cosmetic welds in overall mass properties calculation.

Weldments are yet another aspect of product design that often requires painstaking management to ensure accuracy and compliance with company design standards. The built-in weldment design environment in Autodesk Inventor 10 makes it easy to model welds in 3D and automatically generate associative 2D documentation of designs. This advantage improves design quality by ensuring that design changes update weldments automatically and documentation reflects the correct symbols for downstream use in the manufacturing process.

About the Author: Kevin Schneider

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