A bend table specifies the bend allowance for a specified material thickness at specific radii, and bend angles for the flat pattern analyzer.
If a specific bend angle or bend radius is not in the table, the flat pattern analyzer interpolates between adjacent cells to determine a value.
The table arranges bend deductions in rows and columns. Each row specifies a bend angle. Each column specifies a bend radius. All columns in the bend table must contain values. Decimal values use the dot character (.) as a separator, not a comma.
You can generate flat patterns by unfolding sheet metal features using a uniformly applied linear KFactor, a bend table, or custom unfolding equation. Because a bend table can allow for specific (nonlinear) equipment behavior, parts produced from models using bend tables are closer in tolerance to the folded model.
A bend table for a particular part needs rows for only the angles used within the part. If a part uses only a single bend radius, a bend table requires only a single column. If a part has only 90 degree bends of a single bend radius, there is no benefit in using a bend table versus adjusting the KFactor value. A useful bend table for a particular shop floor machine has a full-range of angles and bend radii. Each cell in such a table requires measured sample pieces to ensure the highest accuracy.
A sample bend table is available in a spreadsheet. You can customize the sample spreadsheet by copying and editing tables.
A bend table file can contain multiple bend tables as long as the tables are for different materials or thicknesses. Typically, a bend table file contains a bend table for each sheet thickness that is used. Since aluminum deforms differently than steel, create a separate bend table file for each material type.
You can access the integrated editor to create and edit bend tables in either text files or spreadsheets. You can also edit bend tables with a text editor or spreadsheet. You can import text files and paste in ranges of cells.
Sample Imperial and metric bend tables are provided as spreadsheet files. The bend deduction values in the sample bend table spreadsheets are based on formulae. The true value of a bend table is the ability to provide consistent and predictable results from your machinery and tooling. You can use the supplied samples as a starting point for the creation of tables that reflect your particular requirements.
Sample bend table text files and spreadsheets are installed at:
Windows 7 and Windows 8 [drive]\Users\Public\Documents\Autodesk\Inventor [version]\Design Data\Bend Tables
Bend tables are saved as an ASCII text file (*.txt).
If the parameter falls outside the range of values, the analyzer applies the T3 tolerance to determine if the parameter is valid.
Units of measurement can be m, cm, mm, micron, inch, ft, or yd. (Centimeters is the default.)
Tolerances determine whether a parameter in the part model is valid and are used at the minimum and maximum values only. For example, if a bend table file has the tolerances listed previously and a maximum bend radius value of 0.05, the analyzer finds a correction value for bend radii up to 0.06.
Tolerances 2 and 3 are for special conditions only, as noted in the table. If tolerances are not specified in the bend table file, the default values are /T1 = 0.0001 (thickness), /T2 = 0.01 (radius), and /T3 = 0.01 (angle).