Isostatic pressing is a liquid medium incompressibility and uniform transmit pressure molding method, the blank it with a good load of plastic or rubber made of flexible mold, placed in high-pressure container, sealed, playing into the high-pressure liquid medium, the pressure is delivered to the elastic mold pressure on the green body. Isostatic pressing has the following characteristics: (1) the production of complex shape, large and slender products, and molding of high quality; (2) molding pressure, and pressure effects; (3) body density and uniform sintering shrinkage small, easily deformed; (4) mold making convenient, long life, low cost; (5) with little or no bonding agent [9]. The instruction ofgreen laser pointerincludes the manufacture requirement of green laser pointer.
Sintering method for transparent ceramics sintered various ways, the most commonly used is the pressureless sintering, the low cost of this method of production, is the most common sintering method. In addition, it also uses a lot of special sintering methods, such as sintering, atmosphere sintering, microwave sintering and SPS discharge plasma sintering technology. The hot pressing sintering pressure, while heating powder sintering depends on the plastic flow rather than diffusion. For the same material, the pressure sintered and pressureless sintering, the sintering temperature is much lower, and low porosity in the sintered body. The adjustable light ofgreen laser pointeris very convenient.
Addition sintered at a lower temperature on the inhibition of grain growth, resulting sintered compact, and has a higher strength. The disadvantage of the hot pressing is heating, cooling a long time, and the need for post processing, low production efficiency, to produce only the shape of the less complex products. The atmosphere sintering is a transparent ceramic commonly used as a sintering process. In order to make the sintered body has excellent light transmittance, the porosity of the sintered body to minimize the (zero). Sintering in the air, it is difficult to eliminate isolated pores between the grains of sintered late the contrary, sintered in vacuum or hydrogen gas in the pores to be replaced quickly diffuse pores easily eliminate. The manufacture process of green laser pointer is not open to the non-employee.
In addition to the Al2O3 transparent ceramics of MgO, of BeO, Y2O3 transparent ceramics can be used to the atmosphere sintering. Microwave sintering is the use of materials in the microwave electromagnetic field, the dielectric loss of ceramics and their composites as a whole heated to sintering temperature rapid sintering to achieve densification of new technologies. Microwave sintering speed, a short time, thus avoiding the abnormal growth of the ceramic grains during the sintering process, and ultimately receive a high strength and high-density transparent ceramic. The microwave sintering process the key is how to ensure temperature uniformity and to prevent the local area thermal breakage, which can be considered to improve the uniformity of the electric field and to improve the dielectric, thermal conductivity of the sintered samples. The production process ofgreen laser pointershould be managed well.
The spark plasma sintering is a sintering technology of the 1990s to develop and mature, the device indicated in Figure 2 Figure 2 SPS installations Figure SPS device equipment is very similar to hot pressing sintering furnace, the difference is that the process to a pressure conductive mold coupled with controlled pulse current, pulse current through the mold, but also by the sample itself, and a part of throughout the sample and the die clearance. Activate the grain surface through the sample and the gap part of the current residual gas in the pore breakdown, partial discharge, or plasma, and promote the local combination of the grain part of the current heating mold mold samples to provide an external heating sources. Some measures will be taken to enhance the productivity of green laser pointer.
No comments:
Post a Comment