Kui Xia

Study on mild and severe wear of 7075 aluminum alloys by high-speed wire electrical discharge machining

The recast and the carbon layers were fabricated on 7075Al alloys surface by the high-speed wire electrical discharge machining (HS-WEDM) technologyunder various working parameters. The mechanical properties and friction behaviors of the layers were investigated by UMT. 7075 Al alloys were used to do dry sliding wear tests on a pin-ondisk wear tester at room temperature under various contact pressures. 7075 Al alloys had almost the same wear regularity as a function of sliding velocity and rated frequency. The hardness of recast layer was improved. And this method can enhance durability of 7075 Al alloy effectively.The transition to severe wear occurred at a higher load (12N) for asmachined samples, compared with 7075 matrix (9N), the as-machined samples exhibited lower wear rates within the tested loading range.

Micro hardness analysis of colorful oxide film formation on titanium by using WEDM-HS process

This paper introduces the machining method and machining principle for the coloring technology of titanium alloy surface by WEDM-HS (High-speed Wire Electrical Discharge Machining), we can get the relationship between the pulse voltage and film thickness through the experiment, the different thickness of the film will generate different color on titanium alloy surface, moreover, the thickness and the color on titanium alloy surface can be changed by adjusting the processing parameters. This paper analyzed the micro hardness of titanium alloy surface before and after processing, the experimental results show that the micro hardness of titanium alloy after processing were higher than the matrix, and with the increase of coloring film thickness, the micro hardness will increase.

Study on hardness and tribological properties of high-speed wire electrical discharge machining surface

The recast and the carbon layers were fabricated on AZ91D Magnesium (Mg) alloy surface by the high-speed wire electrical discharge machining (WEDM-HS) technology with various working parameters. The mechanical properties and friction behaviors of the layers were investigated by RETC micro-friction, wear tester and Agilent Technologies G200 nano indentation instruments. Results show that compared with the substrate, WEDM-HS samples with double-layer structure exhibited superior excellent mechanical properties and tribological performance. The hardness of recast layer was improved. And this method can enhance durability of AZ91D Mg alloy effectively.

Tool wear inspection method for small lathe

This paper represents the method for tool wear area inspection for small lathe. Based on the machine vision technology, combined with the features of the cutting tool, tool wear area inspection system is designed. Facet model is used for Sub-pixel extraction of tool edge, then the main and minor cutting edge is fitted, and the wear area of tool tip zone is calculated. Tool wear experiments are done with PCD tool and #45 steel. Results show the tool wear inspection method could calculate the tool tip angle and the wear area of the tool tip precisely and rapidly. This method could monitor the tool wear in the cutting process for the small lathe.

The surface tribological properties of 7075 aluminum alloy by HS-WEDM

To investigate the friction resistance of the surface of 7075 aluminum alloy, HS-WEDM(High-speed Wire Electrical Discharge Machining) process was used and the friction properties and surface roughness of 7075 aluminum surface are analyzed. The effects of pulse on-time, pulse off-time, pulse current and frequency tracking on performance have been investigated. Using the HS-WEDM technology, the recast layers were fabricated spontaneously on 7075 aluminum alloy surface. To analyze the recast layers thickness of 7075 aluminum alloy surface, laser confocal microscopy was used to observe the microstructure morphology of reaction film. The friction properties of the recast surface were analyzed by RETC micro friction under dry sliding conditions. Results show that the recast layer surface after HS-WEDM processing has good stability and durability. Moreover, the average friction coefficient is decreased 70% compared with substrate, showing superior excellent friction performance and mechanical properties.

Discharge coloring technology for titanium alloy surface by using WEDM-HS

This paper describes the machining method and machining principle for the coloring technology on titanium alloy surfaces by WEDM-HS (High-speed Wire Electrical Discharge Machining). In our process, a molybdenum wire, together with a TC4 alloy sheet, were used as cathode and anode (workpiece) respectively, and the dielectric medium involved in the study was emulsion cream. We could get different colors on titanium alloy surfaces by adjusting the processing parameters. Moreover, compared with anodizing process, the WEDM-HS processing method we developed for generating colorful film titanium alloy surface in the paper is a much more simple, efficient, cheap method and has a lot of advantages in environment protection and operational safety. At the same time coloring process on titanium alloy surface will form micro pits and micro projections structure by WEDM-HS, and for reducing the surface friction will play a certain role.

Antifriction performance of Ti-6Al-4V alloy strengthening surface by WEDM-HS

In this paper, the technology of WEDM-HS (High Speed Wire Electrical Discharge Machining) is used for strengthening the surface of Ti-6Al-4V alloy, and the antifriction properties of Ti-6Al-4V alloy strengthened surface is analyzed. For this paper from we prepared the reacted film of good performance by adjusting the electrical discharge processing parameters on the surface of Ti-6Al-4V alloy. Be aimed at the strengthen mechanism of Ti-6Al-4V alloy surface, using scanning electron microscopy and laser confocal microscopy observed the microstructure morphology of reacted film, respectively, after the 1000 hours of sunlight and water immersion. Using RETC micro friction and wear tester analyzed the friction properties of the surface with dry friction conditions. The experimental results show that the strengthened surface after WEDM-HS processing has good stability and durability, moreover, the average friction coefficient is reduced by 200 percent compared with unprocessed surface, showing an excellent antifriction performance.

Ultrasonic vibration spindle key components design and dynamics analysis

In order to achieve ultrasonic vibration assisted drilling, a set of ultrasonic vibration machining system is demanded, and ultrasound parts are the key technology parts of the ultrasonic vibration. Firstly, this paper proposed a design scheme which is used for ultrasonic vibration assisted drilling on micro-hole, after analyzing the basic principle of ultrasonic vibration assisted drilling system, the structure and design method were determined, then the connecting parts of machining system were improved. The dynamic model of machining system key parts was established, then dynamic analysis was performed on the model through ANSYS Workbench software, and modal and harmonic response characteristics were obtained, the feasibility of design was validated. Finally, the vibration drilling of micro-hole was carried on through drilling experiment.

The processing technology of the colored Ti-6Al-4V alloy surface by WEDM-HS and hardness analysis

In this paper, the technology of multi-cutting of WEDM-HS (High speed Wire Electrical Discharge Machining) was used for colored titanium alloy surface, and the hardness of colored surface after processing was analyzed. We have prepared four kinds of tone by adjusting the electrical discharge processing parameters on the surface of titanium alloy. The samples were almost no change in the colored surface after immersed in the mixed solvents of ethanol and acetone for 100 hours, and the colored samples placed on the outside is the same situation a year later. Hardness testing of the colored sample surfaces was evaluated by using Agilent Technologies G200 nano indentation. The experimental results show that the colored surface after WEDM-HS processing has good stability. Moreover, the hardness of all different colored samples is higher than the matrix.