By Joe McDiarmid
For many years SOLIDWORKS has had a nifty way of designing sheet metal parts; create them in the formed/bent shape, and then hit a tool called Flatten to get your flat pattern. There are plenty of people who use this workflow for things definitively not made of metal – cardboard and plastic packaging, vinyl wraps and stickers, and all manner of fiber/fabric based shapes used in composite part design are often created using “Sheet Metal” to take advantage of time-saving tools like Flatten and Edge Flange. As many designers of these types of products will attest, this workflow is very powerful, but does have some limitations, and for a long time very curvy, organic type shapes were extremely difficult if not impossible to create this way.
In 2015, many of these users’ prayers appeared to be answered with the arrival of the Surface Flatten tool; allowing you to select several surfaces on a shape or body and automatically create a flattened pattern based off that curved shape – without the need for designing the part with any sheet metal tools! While a big hit, it had some room for improvement, and in 2016 the Surface Flatten tool has been enhanced to include projected sketches and relief cuts to incorporate a wider scope of shapes that can be flattened.
In this example, we have the forward aeroshell of a quadcopter that needs to have some stickers or decals designed for it. Rather than spend a lot of time creating surfaces, or trying to recreate this part using sheet metal tools (good luck with that!), we will use the Surface Flatten tool to create a flat pattern on which art can be drawn, as well as incorporate a cutout of the Hawk Ridge Systems hawk logo and some relief cuts to take strain out of the flat pattern. To begin, click the Surface Flatten tool on the command manager and then select the faces you wish to flatten out as shown in image 1. They need to be connected faces, or else the flat pattern cannot be calculated.
After selecting the adjoining faces you wish to flatten, select a vertex from which to virtually unfurl the flat pattern. This is indicated by the upper arrow in image 2. Then, if there are any cut-outs or projected sketches (such as the logo in our example) you select them from the feature manager tree into the Additional Entities box indicated by the lower arrows in image 2. This will then project whatever the shape you selected is onto the flat pattern, incorporating any stretch or compression so as to ensure the original curved shape you picked is what you will end up with.
Finally, looking at image 3 below you can see a comparison of the flat with and without a relief cut added, in this image you can easily see from the deformation plot of the flat pattern that the relief cut removes a lot of internal stresses in the edges of the shape, making for an easier to wrap/fold sticker.
In image 4, we return to the property manager of Surface Flatten to add the second relief cut sketch indicated by the lower arrows to get the splits in the flat indicated by the upper arrow.
The final result is shown below in image 5, where you can see the flat pattern of the curved body now incorporates the sketch and relief cuts, and this can now be directly exported to a dwg, dxf or an art program for more work. In this manner, you can quickly and accurately create flat patterns for any number of shapes from square and boxy to round and organic, and directly export a shape that someone can cut and then fold/form/roll into the appropriately curved shape.