Investigation into Layered Manufacturing Technologies for Industrial Applications
Additive processes, which generate parts in a layered way, have more than 20 years of history can be defined as layered manufacturing. Layered manufacturing is gaining ground for rapid prototypes (RP), rapid tools (RT) and rapid manufacturing (RM) for production of functional parts. The paper describes which mechanism of layered manufacturing and definition and classification of rapid prototypes can be applied to complex geometries for long-term consistency. The paper demonstrates the application examples of layered manufacturing fulfilling the required physical, mechanical and geometrical properties. The most notable advantage is the integration of production planning and testing within the product development period.
Stepwise Consolidation of Metal Powder by Localized Microwaves for Additive Manufacturing of 3 D Structures
This paper presents local solidification of metal powder, irradiated by localized microwaves, as potential means for stepwise additive formation of 3D structures. Experimental results of metal powder solidified locally by microwaves are presented in forms of spheres and rods in a 1-10 mm range. The feasibility of extending solid structures by adding powder batches and solidifying them locally, as building blocks, is demonstrated as the basic action for a stepwise additive construction. The experimental observations and numerical results suggest that the enhanced electric field between the metallic particles excite electric discharges (micro-plasmas) which initiate the magnetic heating process. The experimental results lead to the development of localized microwave technique for stepwise formation of metal structures, as a low-cost substitute for laser-based technologies for rapid prototyping (RP) and additive manufacturing (AM) systems in >1-mm resolution.
Variability of Reflectance Measurements with Sensor Altitude and Canopy Type
Data were acquired on canopies of mature corn planted in 76 cm rows, mature soybeans planted in 96 cm rows with 71 percent soil cover, and mature soybeans planed in 76 cm rows with 100 percent soil cover. A LANDSAT band radiometer with a 15 degree field of view was used at ten altitudes ranging from 0.2 m to 10 m above the canopy. At each altitude, measurements were taken at 15 cm intervals also a 2.0 m transect perpendicular to the crop row direction. Reflectance data were plotted as a function of altitude and horizontal position to verify that the variance of measurements at low altitudes was attributable to row effects which disappear at higher altitudes where the sensor integrate across several rows. The coefficient of variation of reflectance decreased exponentially as the sensor was elevated. Systematic sampling (at odd multiples of 0.5 times the row spacing interval) required fewer measurements than simple random sampling over row crop canopies.