Zhi Xin Jia

Study on Simulation and Experiment of Drilling for Titanium Alloys

To investigate the drilling process of titanium alloys, the three dimensional finite element model of two flutes twist drill was established. The drilling process of Ti6Al4V was simulated based on the presented model. In addition, the drilling experiments were carried out under the different spindle speed and feeding speed. The drilling forces of the experiment and simulation were achieved. The result of simulation agrees with the result of experiment well. It proves that the finite element model is correct. Simultaneously, the results show that more high drilling speed can improve the quality of hole in drilling process of Ti6Al4V obviously.

Effect of the Load Path on Formability of T-Shaped Tube Hydroforming

Based on the analysis of now available evaluation indexes to estimate the formability of T-shaped tube hydroforming, an aggregative indicator is proposed. The effect of load path on the formability of T-shaped tube is discussed by FEM simulation, and validity of the evaluation index and simulations are proved by experiment. Results show that with the broken line load path of 0-35-35-60, the value of aggregative indicator is the greatest and the formability is the best. The optional parameters are testified by experiment and the results are in agreement with the FEM simulation results.

The Mold Design for the Mouse Bottom Cover Based on EMX Software

Injection molding is a major manufacturing method for the fabrication of plastic parts for multi-industrial aspects. The mold design technology experienced the development process of manual draft, 2D CAD design to 3D CAD design. In this paper, the main functions of EMX are introduced firstly. Then the design procedures are presented for molding parts by adopting Mold Cavity functional mould in Pro/E software and the mold base by using EMX software. At last, a mold for the mouse bottom cover is designed using the given method. The result shows that integrated 3D design of mold has significant advantages on reducing labor intensity, improving design efficiency and quality.

Study of High-Speed Plastic Injection Molding and its Mold Structure Characteristics

High-speed injection molding technology refers to the injection speed of rotating screw is about 500mm ~1000mm/s during the injection process. It is extensively used in the fabrication of thin and accurate products, for example, packing containers, CD or DVD disc-based panels, smart cards, optic fiber connecters, etc. In this paper, the advantages of high-speed injection molding technology on cost savings, product quality and productivity are presented firstly. Then the mold characteristics on strength, stiffness, precision, used material, heat treatment, the runner system, the venting system and the ejection system are illustrated. A plastic flowerpot by high-speed injection molding is selected as an example to show the high production efficiency.

Die-Casting Die Design Based on the Application of CAE Simulation

High pressure die casting is a high volume component manufacturing process which is used extensively in many aspects. There are many factors affecting the quality of die-casting die. In this paper, the CAE simulations of filling and solidification processes for die-casting are studied. Numerical analyses are presented for two practical die-casting parts using HZ CAE software. The temperature distributions and filling states in solidification and filling process are presented. Then the deficiencies of the part are predicted. Based on the analyzing results, the structures of the two dies are optimized and longer die service life and high-quality castings are obtained. It is proved that CAE simulation results can offer a helpful reference for die-casting die design.

Local Laser Bionic Blocking Experimental Study of Hot Work Mould Surface Cracks

For the short life of hot work die in enterprise directly caused problems the waste of resources and the rising cost of production. Based on studying the biological prototype of crack-resistance of plant lamina and found that surface thermal fatigue crack is one of the main factors affecting the service life of hot work mould, it is put forward thoughts about the local bionic laser melting on mould surface to block cracks. Different from the traditional mould surface integral laser transformation hardening (LTH) technology, using laser melting simulating plant lamina to block cracks on the partial surface of mold, life of bionic strengthened die is improved within 1~1.5 times. Experiment results show that a new method is provided to improve the service life of casting mould and promoting this technology will bring significant economic benefits for the mould industry.

Study on the Cavity Defects of Low-Pressure Lost Foam Casting for Magnesium Alloy

Cavity defects of low-pressure lost foam casting (LP-LFC) for magnesium alloy were investigated by using ladder samples and claviform samples.The physical feature of typical cavity defects of LP-LFC for magnesium castings had been tested by optical microscopy and scanning electron microscopy. And the chemical constitution of cavity surface was also tseted by energy spectrometer. The result indicated that the cluster cavity defects were formed with the application of higher vacuum at the metal-mold interface, which caused the liquid-EPS residue in the castings. Some irregular shape cavity defects were caused by slag entrapment or coating slough. These cavity defects could be avoided through reducing pouring temperature, filling velocity and vacuum level, improving the permeability of coating.

Study and Application of CAE Simulation in Die-Casting Die Design

The CAE simulations of filling and solidification processes for die-casting are studied. Numerical analysis is presented for a practical die-casting part using HZ CAE software. The temperature distributions and filling states in solidification and filling process are presented. Then the deficiencies of the part are predicted. Based on the analyzing results, the two die halves are modified and the die-casting parameters are adjusted. The service life of the revised die is increased from 12,000 shots to 20,000shots. It is proved that CAE simulation results can offer a helpful reference for die-casting die design.

Laser Local Stripe Bionic Strengthening of Mould Surface

In order to solve the problems of the waste of resources, and reduce the cost directly caused by the short life of the hot die in enterprises, this paper analyzes the wear of hot die which is one of the main factors affecting service life, and a thought that enhanced mold through laser surface local stripe grid bionic process is pointed out. Different from traditional laser hardening technology, the service life of mold processed by bionic laser melting enhancement simulating butterfly wings is nearly doubled. Experimental results provide a new way to improve die life, and the application of laser local stripe grid bionic process will bring enterprises significant economic benefits for its extension in mould industry.

Detection of Laser Melting Bionic Stripe Quality on Mould Surface Based on Acoustic Signal

In order to rescue the problems of controlling laser bionic strengthening local stripe of mould surface quality, it is put forward thoughts about the laser bionic local melting stripe of mould surface quality detection based on acoustic signal. Analyzed with the relationship between defocusing distance and acoustic signal characteristic, laser bionic strengthening local stripe quality, the results show that acoustic signal is weakened with the increased absolute value of defocusing distance. As the defocusing distance is 0mm, the role of the laser is primarily ablation and the stripe quality is the worst; the function of laser on the surface materials is too weak to strengthen when the defocusing distance is -4mm; laser on target surface plays its role of strengthening, mainly owing to melting, with defocusing distance of +4mm. Overall tests show that, based on the quantitative detection of acoustic signal characteristic, it could inspect and control the quality of strengthening stripe, and it will realize the overall control of laser bionic strengthening mould surface quality with guiding significance.