Nanjing University of Aeronautics and Astronautics

Qinjiang Liu

Zhongde Shan

Haoqin Yang

Jianpei Shi

Shijie Dong

Dandan Yan

Yufeng Dai

Wanneng Liao

An ultrasonic-assisted permeation and homogenization molding device and method for frozen printing liquid drops are provided. The device includes an ultrasonic generator, a transducer and an amplitude-change pole. The ultrasonic generator generates 20 KHz low-frequency ultrasonic waves, and a flange plate is arranged on a pitch surface of the amplitude-change pole and connected with an outer cavity wall of the low-temperature molding chamber by threads. According to the ultrasonic-assisted permeation and homogenization molding method for frozen printing liquid drops, pre-paved molding sand particles are homogenized and distributed under ultrasonic vibration by adjusting the frequency of the ultrasonic generator in a sand paving process. When a pure water binder is sprayed, liquid drops are sprayed to the surface of premixed molding sand, and then permeate to the bottom of pre-cooled molding sand under the assistance of low-frequency ultrasonic waves to freeze and solidify.

Ultrasonic-assisted permeation and homogenization molding device and method for frozen printing liquid drops

A method for preparing a negative pressure film-covering frozen sand mold includes: directly obtaining a mold cavity of a sand mold through numerically controlled machining of a frozen sand blank; covering a surface, brushed with a thermal insulation coating, of the mold cavity of the sand mold with a softened thin film, and covering an outer surface of the sand mold with a back film to seal a sand box; fixing the frozen sand mold in an air extraction sand box with a vacuum chamber, and extracting air through a vacuum pump, so that the thin film tightly adheres to the sand mold through vacuum suction force; and closing the box to obtain an integral sand mold, and pouring a casting at room temperature or low temperature under negative pressure. The method is environment-friendly, and the prepared frozen sand mold has high strength and is convenient for sand cleaning.

Method for preparing negative pressure film-covering frozen sand mold

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Nanjing, China

Qinjiang Liu