Advanced Materials Research Vols. 139-141

Abstract: A new type of servo direct drive turret punch press is presented. A servomotor to drive the eccentric-toggle mechanism is used in our design, which combines the advantages of mechanical and hydraulic turret punch press. The displacement, velocity, and acceleration of the punch are calculated, through the kinematics analysis. So, the motion of the punch is controllable through the rotation of the servomotor. Then, the inverse kinematics analysis is studied in detail, and the corresponding motion of the servomotor can be gotten, for different punch motion curves, according to the production requirement. For example, when we design a motion of the punch for a particular stamping process, the motion of servomotor can be obtained through the inverse kinematics analysis. Finally, Output force is acquired by static force analysis, which decides the working capability of the mechanism.

Abstract: For the system of a large-area laser projection image exposure using 351nm XeF excimer, its constitution, optical design parameters, and manufacturing process are introduced. The system is capable of patterning in photoresists for large-format products, with feature sizes ranging from 10 µm to below 1µm and substrate sizes ranging from 100×100mm to 600×900mm. 351nm excimer is used in this system because of its capability for exposure of conventional photoresists. Large-area lithography refers to the patterning on such areas with the desired resolution and seamless scanning. Along with the demands for lithography equipment that can provide high-resolution imaging capability, high-precision alignment performance and lower manufacturing costs, it is important for us to design and manufacture such equipment. Some key problems such as laser illumination optics, projection optics, positioning and controlling machinery, are described here. The existing problem and solutions in the optics and machinery are analyzed and discussed.

Abstract: Due to the difficulty in arrangement of thermocouples, temperature measurement in grinding presents a number of challenges, particularly in high speed cylindrical-plunge grinding. Based on existing literature, only single thermocouple is considered for measuring the maximum temperature in the grinding contact arc, without considering the overall temperature variation. In this paper, a new method for temperature measurement, named four K-type thermocouples, is proposed aslant along the direction of the width of workpiece which is developed for measuring the overall contact arc in high speed cylindrical-plunge grinding. It is shown that the temperature increases to the maximum with a sharp gradient, then decreases due to the strengthening of cooling effect and the decrease of depth of cut, which is consistent with previous study. The measured temperature signal reveals the generation rule and dissipation rule of grinding heat.

Abstract: In order to provide theory basis for optimizing high-speed milling parameters, the high-speed milling process of titanium alloy Ti-6Al-4V was modeled using the commercial general purpose machining software package ADVANTEDGE. Effects of milling parameters like milling speed, feed per tooth, milling depth and milling width on cutting force and temperature were analyzed. The results show that cutting forces decrease with milling speed increasing, and increase with feed per tooth, milling depth and milling width, and the influences of feed per tooth, milling depth and milling width on cutting forces are significant. The maximum temperature in the cutting zone located on the rake face at a distance of about 0.02~0.03 mm from the tool tip. As milling speed and feed per tooth increase, the maximum temperature in the cutting area increases. The milling speed has significant impact on cutting temperature, but the milling depth has little impact.

Abstract: According to high-frequency chattering of workpiece overhanging the support area of the NC rotary table while gear milling, overhanging rigidity of the table was analyzed and the auxiliary support program was bring up. Online test of gear milling can be used to establish dynamic model of the overhanging structure. For enhancing increase the axial rigidity and circumferential damping of the rotary table, a kind of auxiliary support apparatus with hydraulic pressure was designed to reduce the influence of high-frequency chattering on gear milling, which doesn’t affect circular division accuracy. As a result, efficiency of gear milling was increased more than 3 times and the machining diameter of workpiece was increased from 2250mm to 3200mm, so the auxiliary support equipment can be used on many kinds of NC rotary table and machine tool.

Abstract: . Five kind of carbon steel were chosen to do the test of CO2 laser micropore drilling in the paper, it were obtained that the influence curves of laser power, pulse width, defocusing amount and repetition rate to the upper aperture and the taper of the hole, and the influence of laser parameters and the carbon content to the drilling quality were system analyzed using double factors without repeating test method, the result show that the value of laser power and pulse width has significant influence to the upper aperture, to taper of hole is less. The influence of the repetition rate of laser and defocus amount to the upper aperture was weak, and the influence to the upper aperture was very significant with the change of the value of carbon content and the repetition rate.

Abstract: In this study, surface roughness generated by face milling of 38CrSi high-strength steel is discussed. Experiments based on 24 factorial design and Box-Behnken design method are conducted to investigate the effects of milling parameters (cutting speed, axial depth of cut and radial depth of cut and feed rate) on surface roughness, and a second-order model of surface roughness is established by using surface response methodology (RSM); Significance tests of the model are carried out by the analysis of variance (ANOVA). The results show that the most important cutting parameter is feed rate, followed by radial depth of cut, cutting speed and axial depth of cut. Moreover, it is verified that the predictive model possesses highly significance by the variance examination at a level of confidence of 99%. And the relationship between surface roughness and the important interaction terms is nonlinear.

Abstract: Piezoelectric (PZT) material is widely used to drive micro-positioning platform, but the energy density of PZT is low, which restricts the application of PZT micro-positioning platform. In order to overcome its disadvantages, A kind of new micro-positioning platform actuated by giant magnetostrictive material (GMM) was presented in the paper. Based on integrated optimization method, structure designing, magnetic circuit designing and temperature control designing were carried out. The dynamic performance of GMM micro-positioning platform was simulated, and simulation result shows the designing is feasible. The prototype was manufactured, and the measurement system was set up. The experiments on the platform were carried out, and experiment results show that the platform has good output performance with positioning accuracy of ±0.03μm and load capacity of 50kg, and can meets the requirements of large-power system.

Abstract: The energy balance of system is one of the basis for the dynamic design of machine tools structure. The paper applied finite element technique to machine tools dynamic design based on the energy balance, in view of finite element model of machine tools dynamics structure, mean squared deviation of various energy distribution was used to describe the structural dynamic characteristics quantitatively, and the method was combined with structural dynamic optimal theory to establish the improvemental direction. The author applied the technique to the structural dynamic characteristics analysis of a surface grinder, through the energy distribution analysis and quantitative analysis of structural dynamic characteristics of the grinding machine tools, the weak link of the grinding machine structure was found, which had instruction function for structure optimization of the grinding machine.The result proved this structure dynamics design technique had obvious superiority.

Abstract: This paper mainly researches on the effect from high-speed shearing tool to the quality of stainless steel tube cutting. At first, the relationship between contour line of vertical blade and the direction of shear force and chip flow are studied, and the influence on the quality of shearing caused by the size of blanking clearance is analyzed. Then a new blade contour line that made most of the iron chippings is located outside of the tube and reasonable blanking clearance is obtained. Further, based on the tearing caused by single-blade shear on the top of steel tube, the shape and angle of the vertical blade are studied, and the structure of the vertical blade nose is optimized, which improves the shearing quality of the blade. Finally, the numerical simulation of the process of shearing is done to verify the feasibility of the designed structure by the finite element software DEFORM.