Search

In EDM drilling, the accumulation of debris is the main factor leading to abnormal discharges and process instability, which prevent the processing of microholes with a high aspect ratio. To fabricate microholes with an ultrahigh aspect ratio, bubbles produced by an electrochemical reaction were applied to assist electrical discharge machining (B-EDM) in tungsten materials. The mechanism and machining performances of the B-EDM method were investigated. The results showed that bubbles produced by electrochemical reaction on both the surface of the electrode and the workpiece prevented the accumulation of debris at the bottom of the hole, which improved machining stability. This process is effective in enhancing drilling performance in deep microholes by improving such parameters as the material removal rate, electrode tool wear, longitudinal section topography, and achieved aspect ratio. Experimental results showed that the processing time and electrode wear of B-EDM were approximately one third those of EDM in the processing of 20 mm through-holes. A hole with a diameter of 0.22 mm and depth of 120 mm was successfully fabricated by B-EDM on tungsten within 130 min.

Compared with the traditional framework dense structure, strong embedded squeeze skeleton dense cement stabilized crushed stone has a stronger embedded squeeze force, the more excellent mechanical properties. This article briefly describes strong embedded squeeze the skeleton dense cement stabilized crushed stone grading design and mechanical properties, and strong embedded squeeze Framework Grading cement stabilized crushed stone in the construction of many materials Segregation. Through the experimental contrast research with traditional construction method, the new method almost eliminate the problems of mixture segregation, which can be used for reference in construction application.