Complex product handling requirements in manufacturing plants can be met with conveyor screws. The product sits inside the groove of the screw which rotates about its own axis, thereby imparting the desired motion to the object. In the adjoining figure the elliptical bottle translates as well as rotates about its own axis as the screw rotates. A video of a conveyor screw from a proprietary source can be seen here.
Traditionally, conveyor screws have been designed via a discretized approach using boolean operations. This results in thousands of sliver faces and a non-smooth solution. Figure below shows an example of such an approach. Download a 3D model of the same in pdf format. Scroll to the bottom of the page for directions on viewing the 3D pdf.
In our approach, the surface of the screw is designed by compounding the desired motion of the object with the rotation of the screw and sweeping the product along the resultant motion. The volume thus swept is subtracted from a cylinder to obtain the screw. Figure below shows an example of screw designed using our approach. Download a 3D model of the same in pdf format. Directions on viewing the 3D pdf are given at the bottom of the page.
You will need Adobe Acrobat Reader 8.0 or upwards in order to view 3D pdfs. Download the 3D pdf on your computer and open in Acrobat Reader. After opening, enable double-sided rendering by right-clicking on the workspace -> 3D Preferences... -> 3D and Multimedia Options.