Ningxia Machinery Research Institute (China)

Abstract In response to the difficulty of accurately analyzing the vibration characteristics of guide frame lifting platforms using multi-rigid body models, this paper proposes a flexible-rigid coupling dynamic equation and simulation model. By integrating ANSYS APDL and ADAMS, an organic replacement between the flexible components and rigid bodies is achieved during the process of flexibilizing the lifting platform. A joint ANSYS-ADAMS simulation is conducted to analyze the axial vibration characteristics of the guide frame lifting platform under standard operating conditions. Additionally, simulations are performed to assess the impact of various operating conditions, including running speed, load magnitude, off-center loading, and braking time, on the vibration characteristics of the platform. The accuracy and validity of the proposed model are verified through experimental data on axial vibration characteristics and vibration acceleration. This research provides a theoretical foundation and model support for subsequent structural optimization, comfort design, and vibration pattern studies of lifting platforms

Diamond-like carbon (DLC) coatings have emerged as a focal point in advanced carbon materials research due to exceptional tribological properties, including ultralow friction coefficient, exceptional wear resistance, ultrahigh hardness, and chemical inertness. Deposition of DLC coatings on metal components represents an innovative solution to enhance wear resistance in engineering applications. However, suboptimal adhesion strength between coatings and substrates, coupled with inherent material limitations, critically compromises the tribological performance. This review systematically examines recent advances in improving the wear resistance of DLC-coated metal components. First, the fundamental wear mechanisms governing both metallic substrates and DLC coatings under service conditions are elucidated. Next, three pivotal technologies, substrate material treatment/strengthening, coating structure design, and elemental doping, all demonstrating significant efficacy in wear resistance enhancement, are critically analyzed. Furthermore, a comparative assessment of these techniques reveals the synergistic potential in hybrid approaches. Finally, a concise summary of the outlook is presented.

Injection behaviors of printheads are concerned by engineers since they affect the whole working performances and the printing quality of 3D printing device. In view of the quality instability issue for sand molds caused by the fluctuation of the droplet injection performance, a study on the relationship of the driving waveform parameters with the droplet injection performance of a casting sand mold printhead and the printing quality of the sand mold was carried out. Comprehensively considering the applied background of 3D printing in casting sand molds and using the separation of variables method, the quantitative relationship between the driving waveform parameters and the droplet injection characteristics was set up, and the injection performance of the printhead under the current waveform was evaluated through experiments. This article puts forward an optimal waveform for use in casting sand printing. Based on the analysis of existing conclusions, by using special equipment for casting sand mold 3D printing, the printing quality of the sand mold under the new waveform and the current waveform was studied via a comparison experiment. The results show that the new waveform is more suitable for sand mold printing of high-viscosity fluid, as it avoids the presence of satellite droplets. The qualification rate in terms of the sand mold size is enhanced by 44%, and the mechanical properties of the sand mold are effectively improved. This study provides a reliable basis for ensuring dimensional accuracy in the application of 3D printing technology in the precision casting field.

Sintering is the key process to a pressureless sintering silicon carbide ceramic. From the perspective of industrial production, this paper discusses the influence factors of big size silicon carbide ceramic sintering from three aspects: sintering curves, the density of green body and particle size of raw material. The results were as follows: (1) Under the conditions that heating rate from 1000 to 1500 °C and from 2100 to 2150 °C is 3 °C per minute and 0.5 °C per minute respectively, a big size product of densification of the ceramics has been obtained. (2) Using dry pressing at 50 MPa, dwell time 2 min, and then with CIP at 180 MPa, dwell time 5 min, the green body densities will more uniform from center to edge. (3) Applying raw materials particle size below 0.6 μm the big size product will get more dense material. Combining with the above three methods. The final product can achieve densification. The sintered sample can been achieved with density of 3.12 g/cm3, Vickers hardness of 26 GPa, and three-point flexure strength 420 MPa.

Premier Li Keqiang put forward the "Internet +" action plan, with the "Internet + education" and "big data + education" era, based on the Internet and BYOD (Bring Your Own Device) mobile cloud teaching methods to become modern classroom teaching reform Trends and trends. Ningxia Institute of Technology was identified as the first batch of local undergraduate colleges transition pilot schools, e-commerce professional as the autonomous region to focus on cultivating construction projects, how to expand teaching time and space, enhance teaching attraction, stimulate students to learn enthusiasm and autonomy, expand quality education Resources benefit side, become the urgent problem to be solved. This paper studies the content, methods and methods of e-commerce in the background of "Internet +" under the background of "Internet +", so as to be able to reform the problems existing in the teaching of e-commerce in colleges and universities and improve the teaching quality of e-commerce.

NC machine plays an irreplaceable role in the modern manufacturing because of its high machining processing accuracy, quality stable, flexibility. Through using the Renishaw ML10 laser interferometer detect the positioning accuracy and repositioning accuracy of X axis and Z axis of the HTC20 series of NC machine tools. According to the detection result compensate NC system to meet the machining accuracy requirement. The result shows that the error compensation of NC system is a effective method to improve the position accuracy of NC machine.