Allowance Method for Developments (3-D SM)

The bend areas for sheet construction are modelled as approximated cylinder segments. During development, the individual segments are transformed to a plane and assigned additional stretching. This is to allow material elongation to be taken into account in partially plastic bending. HiCAD also provides the empirical allowance methods standard in practice.

A particular calculation method is represented by means of a system file. These files are prepared as examples, but in practice each user will store one or more of his own methods in this way. Before developing, you can select the system file via Sheet Metal > Sheet development > Technology parameters .

Several basic types of calculation method have been prepared. The user will choose one of these types and specify it by setting the parameters to company-specific values. The basic structure of these files, however, is the same. It is divided into comment, type ID and table.

The following allowance methods are available:

 

For the creation and/or editing of the files you use the ABWEditor tool in the EXE directory of your HiCAD installation.

In the left column (1) of the Editor you can see the names of the ABW files that are stored in the corresponding HiCAD system directory (../MAKROABW). Only the files stored in this folder will be recognized by HiCAD as available allowance methods and offered for selection in the corresponding dialogue.

When you click on an allowance method in the list, the content of the file will be shown in tabular form on the right hand side (2) of the Editor.

This format-bound table has 4 columns and interval limits of 999.000. For method F (5) only 2 columns are relevant. For all other methods, all 4 columns are relevant.

The columns have the following meaning for the allowance method:

 

Click the column headers to sort the column contents in ascending or descending order. The records of an ABW file must have a particular order, which will be automatically applied upon saving. You can click the Sort data records icon to restore the correct sorting order. The Copy data record function inserts a marked table row once more. If a sorting of the table has already been done, this new row will be inserted as the next row; otherwise, it will be inserted as the last row.

The displayed File name (3) can be overwritten, as well as the individual numbers in the data records. The Type of allowance method (5) can also be edited. The following types have currently been implemented:

 

The Comment (4) can be edited on the second tab of the dialogue.

The comment in the ABW files that are supplied with HiCAD consists of a description of the method and the meaning of the individual columns.

The two cogwheels next to the file name indicate that this is a system file, i.e. an ABW file that is stored in the HiCAD system directory.

If you want to load a different file (e.g. by clicking a different system file in the list or by creating a new file) you will be asked whether you want to save the changes to the current file.

In the top right corner of the Editor (6) you can find the following icons:

Save

Save as...

Save as system file

Restore

 

With the help of the icons (7) at the top left you can manage the ABW files:

If you want to create company-specific allowance methods it is recommended to modify existing files and save them as system files.

 

Examples:


CHAMFER for 'Puzzle piece' Design Variant

The CHAMFER allowance method has been developed to match the requirements of the Puzzle piece Design Variant.

Before insertion of the variant, the CHAMFER allowance method must be selected for the Sheet Metal part. Proceed as follows:

  1. Identify the Sheet Metal part. On the Sheet Metal tab of the Ribbon, select Sheet development > Param. .
  2. Activate the With allowance checkbox to ensure that the allowance method will be considered.
  3. Select the CHAMFER allowance method from the drop-down list and confirm with OK.


ACP and ACP outside for aluminium composite panels with bend zone

Aluminium composite panels can, for instance, consist of two 0,5 mm aluminium cover sheets with a mineral core. In HiCAD the plate is represented simplified as a one-layer sheet. Since the weight calculation is done based on a homogeneous material, an own material is assigned to the panel.

For Aluminium Composite Panel blanks with bend zones (i.e. no milling edge zones; these will only be available from Version 2300 onwards), the allowance methods ACP amd ACP_outside are available. Developments and milling dimensions are derived from the 3-D drawing dimensions. Per edge, the corresponding linear dimension will be subtracted from the final dimension. The sum of the milling dimensions equals the blank dimensions.

(1) Section through blank for bending simulation
(2) Section through the sheet metal part of an aluminium composite panel
(3) Milling dimension
(4) Final dimension
(5) Subtracted linear dimension per edge

 

If the bend zones for the composite panels are created in the standard mode, they will have a cylindrical shape as shown in the image below(8). In contrast, if the milling edge mode is used for construction, grooves will be milled along the bend zones before the bending takes place. The result will be one aluminium top sheet, as shown in the image below (6,7). To achieve a geometrical length adjustment of the modelled sheets with cylindrical bend zones on the produced real sheets with milled foldings you can use the files ACP.ABW and ACP_OUTSIDE.ABW. For bend zones with inside millings (6), use the allowance method ACP, for bend zones with outside millings (7), use the allowance method ACP_OUTSIDE.

If the sheets are constructed in the milling edge mode, the model will contain the milled bend zones. A length correction will not be necessary. No allowance method can be selected. Eine Längenkorrektur ist nicht notwendig. Es kann kein Zuschlagverfahren gewählt werden.

Bend radius (BRAD): 0.01 (Standard, for inside millings)

Bend radius, milled outside (BRAD_OUT): 1.50 (Exception, for outside millings)

(6) Inside milling
(7) Outside milling
(8) Composite panel with bend zone

New/Change Technology ParametersBlank Parameters

© Copyright 1994-2018, ISD Software und Systeme GmbH
Version 2302 - HiCAD Sheet Metal
Date: 14/09/2018

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