Numerical Simulation of Temperature Field for Laser Rapid Prototyping
The temperature field model for laser rapid prototyping is established by the mathematical treatment of laser power input. Temperature fields with different process conditions are numerical simulated, and the temperature is Gaussian distribution as the intensity distribution on laser beam cross-section. Temperature fields for laser rapid prototyping ware measured by thermal imager in real time. The simulation results agree with the experimental measurement. Experiments show that the temperature field model can be used for computer analysis and optimizing of laser rapid prototyping processing.
A note on rapid manufacturing process of metallic parts based on SLS plastic prototype
Abstract The polystyrene prototypes were produced by selective laser sintering (SLS) rapid prototyping process. According to properties of thermal depolymerisation of prototype material, the rapid manufacturing process for metallic parts was worked out through the combination of rapid prototypes and precise casting technology. After prototypes burned out in precision shell moulds, a series of complicate thin walled Al-alloy parts have been successfully made by vacuum differential pressure casting (VDPC) process. Accuracy of parts and influencing factors were investigated and discussed. The process combines the advantages of producing high-qualified metallic parts with shortening the period of production cycle.
Anomalous Annealing Behavior of Arsenic Implanted Silicon as a Function of Dose and Energy
Anomalous annealing behavior of damage in As implanted Si has been investigated by channeling effect measurements. Room temperature As implants with doses from 1014 to 2 × 1016cm-2 at energies ranging from 50 to 250 keV into Si were annealed over the range of 600°C to 1100°C. Anneal temperatures ≥ 950°C reduce the disorder for ion doses of 0.5 to 1 × 1016 cm-2 at energies between 50 and 250 keV. Anomalously high residual disorder was found for the intermediate doses of 2 × 1014 to 2 × 10/cm2 implanted above 100 keV. For this intermediate dose, annealing of implants performed at liquid nitrogen temperatures did not show significant reduction in this damage. However implants at 200° to 300°C indicate a lower amount of damage compared to the room temperature implants.