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Rapid prototyping and molding

update:10-08-2019
abstract:

Rapid prototyping is an important technology in new pro […]

Rapid prototyping is an important technology in new product development. In the past, people have always believed that rapid mold-making is limited to small-scale trial production. However, in the past years, rapid mold-making has also been used in medium-volume batches, and even in large quantities, the manufacture of quasi-durable metal molds.

The spray molding process is to form a metal spray layer on the surface of the prototype, and then to reinforce the molten layer, and to be removed by spray to obtain a metal mold. The high melting point melting material can make the surface hardness of the mold reach 63HRC.

The direct rapid manufacturing metal mold (DRMT) method mainly includes a selective laser sintering method (SLS) using a laser as a heat source and a deposition method (PDM) based on a laser melting deposition method (LENS) using a plasma arc or the like as a heat source. Forming three-dimensional printing (3DP) method and metal sheet LOM technology, etc., SLS molding accuracy has been improved. The shrinkage rate has been reduced from 1% to less than 0.2%. The density and mechanical properties of parts manufactured by LENS are much higher than those of the SLS method, but there is still about 5% porosity, which is only suitable for manufacturing simple geometry. Shaped parts or molds, the surface quality is not too high due to the bonding of unmelted particles

Shape deposition manufacturing method (SDM), using the welding principle to melt the welding consumable (filament), and by means of the thermal spraying principle, the ultra-high temperature droplets are deposited layer by layer to realize the inter-layer metallurgical combination, which can avoid the above-mentioned principle based on the lamination method. RT technology will produce side step effect, resulting in low precision, poor surface quality, and low comprehensive mechanical properties.

Rapid tooling technology is developed and developed in competition with traditional machining technology, but the milling speed is as high as 100.000r/min, and the high-speed milling technology with excellent surface precision has become the biggest competition of DRMT technology.