VISI will allow you to unfold any metal parts you have with relative ease and gives you flexibility when doing so to maintain the integrity of your part.
Start the process by opening or importing the part into VISI. Using the option in the “Progress” dropdown “Part Study”. After selecting the part through the Part Analysis Build the options for defining different part properties opens up. This window allows for the defining of part material properties and different unfolding methods.
The material properties are sorted by “Family” (brass, copper, steel, aluminum, etc) and “Materials” (specific material specifications within the chosen family). There are default ones that come with the installation of the VISI product, but if you have additional materials to add, you can access the library by clicking the icon in the top left “Family Properties” and then editing in that menu. The thickness of the part can also be defined as “t” and the material side at the bottom of the left column.
The right side of the Part Properties window is devoted to defining the unfolding calculations applied to the part. The first option is for defining the neutral fiber on the bend. Bending a sheet metal part produces stretches and compressions onto the part. If the tension stress is onto the external side of the fold, the compression of material is assumed onto the internal side. The stretching tension increases the original dimension of the part, while compression reduces the dimension. The boundary between stretching and compression is the neutral fiber where the original dimension remains unchanged. VISI offers two methods for finding this value: Manual (select between 1/3, ½, 2/5, and 5/12 where the fractions refer to the position through the metal thickness that you want to define the neutral fiber) or Automatic (using Romanoski, Oehler-Kaiser, or Sharp Corner algorithm methods).
There is also the option for selecting the unfolding type used. Constant length unfolding uses an algorithm that forces the arc length of the bend on the chosen or calculated neutral fiber to remain constant. When the bend is unfolded, the radius and centre point of the selected bend must change to maintain a constant arc length. Constant radius unfolding uses a separate algorithm that forces the radius of the bend on the neutral fiber to remain constant.
Linear extension after the bend unfolds the bend creating a surface with the same radius and adding a plane surface after the bend to have the same neutral fiber length. The linear extension before the bend performs in the same way, but adds the surface before the bend.
After all of the unfolding specfications are set, the actual unfolding steps can be created. Start by selecting the face to unfold from and an origin point. Typically, you can use the automatic unfolding feature for all but the most complex parts to get a flat blank for the part. After the blank is created as a goal to unfold toward, switch to the “Step” tab and add a step to the strip unfolding. A copy of the previous part will be created. By right clicking on each othe bends in the part, a dialog opens to allow for a bend angle specification. Through this, you can work backward through the strip by defining the bends at each step.
Once all of the steps are created, switch to the final “Solids” tab and “Rebuild 3D Parts” to add the material thickness back onto each step.
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