The Modular Design of Turn-milling CNC for Special Stones

Stone products' processing technologies, processes and types have essential differences with metal's, which makes the traditional machine design method can not perform well in the design of processing equipment for special shaped stones. A new design method was used in this paper, which through the establishment of stone typical products and tool mathematical model. The needs of the motion axes was solved by kinematics equations application and the feasible design scheme of the machine tool's function was established. Thus, a new turn-milling combined NC machine tools, which have 8 movement axis and Double 5 axis linkage processing function is designed. Its modular structure design can meet the needs of the most stone material processing.  DOI: http://dx.doi.org/10.11591/telkomnika.v11i5.256

Intelligent Leveling Control Design of the Same Orientation Pursuit Strategy for Suspended Access Platform

A new intelligent levelling system was applied to the suspended access platform (SAP), and a Same Orientation Pursuit Strategy (SOPS) was designed to operate it. Based on SOPS matching test and using the concept of sliding mode control design and Lyapunov synthesis approach, we propose an adaptive fuzzy sliding mode control (AFSMC) scheme for the class of nonlinear systems. This system is proved to be the superior concept in a safer and more intelligent automatic control. Fuzzy controller (FC) and dual-axis inclination sensor are employed for the control system, which automatically changes the motion of lifting equipment according to the inclination of the platform, in order to eliminate the non-level quickly. FC is accepted by the AFSMC scheme. A gate network is used to address the fusion of two sensors’ measurements and develops to recognize situation of level. Moreover, the FC with vibration avoidance is also researched in this paper. The system can achieve the synchronized drive accuracy of multi-point suspended platform. Furthermore, the influence of the disturbance signals and different protect time of eliminating flutter are evaluated in this paper

FRICTION PROPERTIES AND DISTRIBUTION RULE OF LUBRICANT FILM OF FULL CERAMIC BALL BEARING UNDER DIFFERENT SERVICE CONDITION

Full ceramic ball bearings are widely used in extreme and complex conditions, such as ultra-high/low temperature, ultra-high speed, corrosion and insulation, because of their material specificity. In order to reveal the friction and lubrication properties, improve the service performance life of all ceramic ball bearings, a mathematical model of the oil lubrication for full ceramic ball bearings has been established in this paper. The distribution rule of the lubricant film in the contact area under different speeds and loads were analysed. The main factors influencing the peak mutation of the lubricant film pressure are clearly defined. The results are compared and analysed by using a ball-disc rolling lubricant film test machine. The study found that the thickness of the lubricant film of a full ceramic ball bearing is positively correlated with the bearing speed and negatively correlated with the bearing loads. The bearing speed has a relatively large effect on the change in the lubricant film thickness. The pressure of the lubricant film in the contact area is positively correlated with the bearing speed, but it is not affected by the bearing load. Unlike metal ball bearings, the thickness and pressure of the lubricant film have a greater relative rate of change in different positions in the contact area of full ceramic ball bearings. With an increase in the bearing speed, the necking-down effect has a greater influence on the peak mutation of the oil pressure. Only one pressure peak occurs in the oil film in the contact area. The results of this paper play an important role in revealing the friction and lubrication properties of full ceramic ball bearings and improving their service performance and life under oil lubrication conditions

Hybrid Prediction Model of the Temperature Field of a Motorized Spindle

The thermal characteristics of a motorized spindle are the main determinants of its performance, and influence the machining accuracy of computer numerical control machine tools. It is important to accurately predict the thermal field of a motorized spindle during its operation to improve its thermal characteristics. This paper proposes a model to predict the temperature field of a high-speed and high-precision motorized spindle under different working conditions using a finite element model and test data. The finite element model considers the influence of the parameters of the cooling system and the lubrication system, and that of environmental conditions on the coefficient of heat transfer based on test data for the surface temperature of the motorized spindle. A genetic algorithm is used to optimize the coefficient of heat transfer of the spindle, and its temperature field is predicted using a three-dimensional model that employs this optimal coefficient. A prediction model of the 170MD30 temperature field of the motorized spindle is created and simulation data for the temperature field are compared with the test data. The results show that when the speed of the spindle is 10,000 rpm, the relative mean prediction error is 1.5%, and when its speed is 15,000 rpm, the prediction error is 3.6%. Therefore, the proposed prediction model can predict the temperature field of the motorized spindle with high accuracy