Advanced Materials Research Vols. 291-294

Abstract: A highly efficient rough machining strategy for mould cavity oriented machining features is proposed based on the traditional CAM systems. The rough machining strategies for the mould cavity can be calssified as drilling, reaming, slot cutting, lateral cutting and clearance machining according to the extated cutting layers which is generated by the traditional constant scallop toolpath. And the machining methods are differ accodring to corresponding machining features. The strategy proposed in this paper has an great value for the high efficiency mould cavity machining, it can not only ensure the load well-distributed in the machining process, but also raise the machining efficiency and extend the tool life.

Abstract: Nickel-base composite coating reinforced by in situ synthesized multiple carbide particles were fabricated on AISI 1045 steel surface by pre-placed laser cladding. Nowadays most researches focus on the wear resistance. This study mainly focuses on the corrosion resistance property. Investigate the effect of different particle distribution on corrosion resistance of the cladding layers by controlling the amount of Zr, Ti and WC. The microstructure and electrochemical property are analyzed by scanning electron microscope (SEM) and electrochemical test equipment. The maximal particle distribution density and particle area ratio appear when Zr:Ti:WC=1:2:2. The polarization curves show that in 0.05mol/L HCl electrolyte the coatings’ corrosion resistance have positive correlation with particles distribution density and particles area ratio, and all the coatings are significantly better than 314L stainless steel in corrosion resistance.

Abstract: This paper presents the conclusions of machinability tests on a new austenitic stainless steel X6Cr16Ni10MoTiN, which applicated in food processing industry, and describes important concurrent parameters for the cutting zone during the process of turning. The content of this article also focuses on the analysis of selected basic indicators of steel machinability: quality of the processed surface. The results of the article are conclusions for working theory and practice for turning of austenitic stainless steels. Based on the cutting tests, cutting speeds of 60 to 220 m/min, feed rate of 0.06 to 1.2 mm and solid carbide indexable insert CNMG 160404-MF.

Abstract: In order to reduce the thermal error of the motorized spindle and improve the manufacturing accuracy of NC machine tool, the thermal error forecasting models based on multivariate autoregressive (MVAR) method and genetic radial basis function (GARBF) neural network method are proposed, respectively. According to different representations of generation mechanism of motorized spindle thermal deformation, operation efficiency and curve fit precision of these two models are compared. The studied results show that under the same temperature rise variable conditions, MVAR model and GARBF neural network model have almost the same convergence and operation time and relative errors of two models are less than 3%. The results also show that the MVAR model has higher forecast precision in the prediction former stages; in contrast, the GARBF neural network model has higher forecast precision in the latter stages.

Abstract: Optics with free form surface can be achieve special imaging effects and reduce component amounts in optical systems. However, it is difficulty to fabricate high accuracy, damage-free optical surface with free form surfaces by conventional method. Atmospheric plasma machining is a non-contact chemical processing method which can fabricate optics without damaged layer. Numerical controlled atmospheric pressure plasma machining (NC-APPM) method is proposed to machine optical free form surfaces. A new atmospheric pressure plasma jet generator was designed to get Gaussian rotational symmetry removal spot and the spot maximum diameter is 1.5mm. Base on dwelling time algorithm, a sinusoidal wave structure, the pitch 2mm and the amplitude 500 nm, is fabricated on a pre-polished flat silica quartz surface using three-axis numerically controlled machine made by ourselves. The result shows that the amplitude error is 59 nm compare to the expectation value surfaces using numerical controlled atmospheric plasma machining method.

Abstract: Surfaces formed by rotating quadratic curve are widely applied in engineering practice. After having studied machining methods and machines, the CNC grinding method based on macro program B for borosilicate glass elliptical cone surface machine with high precision is proposed. Within the allowable error, the coordinates are calculated according to the equation of axial section curve and the surface is formed with tools moving on axial section curve. Through setting parameters of the lathe, the new canned cycle can be defined to process all different kinds of the elliptical cone surface of same type. With surface triangle adaptive measurement method, machined elliptical cone surface can be detected on coordinate-measuring machine and compared with the theoretical curve. The tolerance resulted from analysis is within 0.025mm. Except ellipsoidal surface all solids of rotation and their deformation, in which their axial sections are represented with equation, can be processed and measured with this method.

Abstract: The article gives a solution to the precise synchronous control of multi-hydraulic cylinders which exist in the large-sized pressure and flattening machine by the virtual axis method. To fulfill the job, the scheme introduces the acceleration feedback to the virtual control model to make the model practical. According to the Newton’s mechanical law and fluid mechanic, the article set up the model mentioned above. The control system presented is investigated through simulation of Matlab under step disturbance and productive practice which successfully demonstrate the effectiveness of the proposed control model.

Abstract: Super purity silica glass was synthesized by Plasma Chemical Vapor Deposition (PCVD) method, during which inductively coupled plasma was used as the heat source. Influence of structure factor of tube and working gas on output power were discussed. The structure factor of tube was confirmed by analyzing the relation between structure factor of tube and coupling efficiency. With the increase of coupling efficiency, output power and plasma radius grow bigger. Super purity silica glass can be successfully synthesized when air was used working gas, during which input power was 100kW and output power reached to 40kW.

Abstract: In order to realize the environmental hazard, this paper presents the investigation of the machinability of ball-end milling process with the dry cutting, the wet cutting, and the mist cutting for aluminum. The relations of the surface roughness, the cutting force, and the cutting parameters are examined based on the experimental results by using the Response Surface Analysis with the Box-Behnken design. The in-process cutting force is monitored to analyze the relations of the surface roughness and the cutting parameters. The proper cutting condition can be determined easily referring to the minimum use of cutting fluid, and the minimum surface roughness and cutting force of the surface plot. The effectiveness of the obtained surface roughness and cutting force models have been proved by utilizing the analysis of variance at 95% confident level.

Abstract: Powder Injection molding (PIM) is a cost-effective process for the fabrication of complex shaped parts, and has a great potential in many applications. In this work, an improved wax-based binder was developed for the powder injection molding of TiH₂ powder fabricated by recycling of Ti chip. Fine TiH₂ powders of about 350 nm in particle size were produced by attrition milling of Ti chip in less than five minutes, resulting from simultaneous self-propagating High temperature Synthesis (SHS) and fracturing. TiH₂ feedstock, a mixture of binder and powders, was fabricated with critical powder loading of 68 vol.%. The rheological characteristics of the feedstock were investigated for subsequent processing step. Viscosity of the feedstock showed pseudo-plastic flow behavior and to optimize injection molding parameter, in-mold rheology curve was generated. The results indicated that the recycled TiH₂ feedstock can be used for the fabrication of the complex shaped parts with good shape.