Charles_West
09-10-2009, 01:57 PM
Second, there is the idea for containerless production of sheet metal. This is also reliant on the large amounts of sunlight that can be focused by thin film mirrors and the insulating properties of space. Imagine taking a homogeneous slug of structural material and spinning it through its center of mass. The material feels a variable tug away from the center of mass, which I believe increases with the square of the distance from the center (perpendicular to the axis of rotation).
If the material is melted after it is set spinning, presumably it will begin to yield to this tug and start to deform. If left to its own devices, the slug would probably expand much more around the edges than the center do to the variable acceleration. This would cause it to cool faster at the edges, which might mean that the center would flow out longer. However, to try and achieve a uniform thickness, the same mirror that heated the material originally would be used to heat the material to selectively alter its viscosity. By continuously heating the thicker sections more than the thinner ones, it might be possible to get something resembling a disk with uniform thickness. This process could probably be monitored and controlled by an infrared camera and a laser scanner. After the operation was completed (if thin film mirrors can be focused sufficiently for this), the disk could be cut into rectangular sections via selective material vaporization (similar to the modern process of cutting sheet metal with a CO2 laser).
This concept also needs more complicated thermodynamic calculation than I currently know how to do. It is additionally complicated by changing geometry and heat conduction through a material. The nice thing about this concept is that it could be tested on Earth, with the resulting shape being something like a parabola rather than a disk.
Thoughts?
If the material is melted after it is set spinning, presumably it will begin to yield to this tug and start to deform. If left to its own devices, the slug would probably expand much more around the edges than the center do to the variable acceleration. This would cause it to cool faster at the edges, which might mean that the center would flow out longer. However, to try and achieve a uniform thickness, the same mirror that heated the material originally would be used to heat the material to selectively alter its viscosity. By continuously heating the thicker sections more than the thinner ones, it might be possible to get something resembling a disk with uniform thickness. This process could probably be monitored and controlled by an infrared camera and a laser scanner. After the operation was completed (if thin film mirrors can be focused sufficiently for this), the disk could be cut into rectangular sections via selective material vaporization (similar to the modern process of cutting sheet metal with a CO2 laser).
This concept also needs more complicated thermodynamic calculation than I currently know how to do. It is additionally complicated by changing geometry and heat conduction through a material. The nice thing about this concept is that it could be tested on Earth, with the resulting shape being something like a parabola rather than a disk.
Thoughts?