Influence of End Mill Manufacturing on Cutting Edge Quality and Wear Behavior

One of the decisive factors for the performance of milling tools is the quality of the cutting edge. The latter results from the process control of the individual steps along the tool manufacturing process chain, which generally includes the sintering or pressing of the blanks, grinding, cutting edge preparation, and coating of the tools. However, the targeted and application-specific design of the process steps in terms of high economic efficiency is currently limited by a lack of knowledge regarding the influence of the corresponding process parameters on the resulting cutting edge quality. In addition, there is a lack of suitable parameters that adequately represent the characteristics of the cutting edge microtopography. This publication therefore investigates the influence of manufacturing processes on cutting edge quality and wear behavior of end mills. On this basis, different characterization parameters for the cutting edge quality are derived and evaluated with regard to their ability to predict the wear behavior.

Mechanical and corrosion resistance properties of AA7075-T6 sub-zero formed sheets

The poor formability of 7xxx series aluminium alloys represents the major limit to their actual use for automotive and aerospace applications. In the present study, the forming temperature effect on the mechanical, corrosion and anodization behaviours of the AA7075-T6 alloy is investigated. To this purpose, tensile tests at different temperatures, ranging from −100 to 300°C, were carried out at different rolling directions. A 6.6% increase of the ultimate tensile strength and a 28.6% increase of the uniform elongation were registered for the specimens deformed at the lowest temperature compared to highest ones. Further, the corrosion resistance of specimens deformed at ultimate tensile strength before and after anodization was increased of 85% and 95%, respectively, compared to the specimens deformed at 300°C. It was demonstrated that high deformation temperatures led to the coalescence of particles and precipitates as well as the decrease of dislocation density, which, in turn, decreased the mechanical and corrosion performances. On the contrary, the deformation temperature of −100°C was found to be the ideal one able to shorten the manufacturing process chain and improve material formability and durability during its in-service life.

Pendekatan alternatif dalam menghasilkan stability lobes diagram untuk memprediksi getaran chatter pada proses pemesinan berdinding tipis

Machining is widely used for finishing process of the entire manufacturing process chain. Machining process of thin plate, however, is not an easy task. This is because excessive vibration (chatter) can rise during operation. To predict the chatter vibration, a stability lobe diagram (SLD) is usually utilized which is strongly dependent on the frequency response function (FRF). This paper proposes an alternative approach for analyzing modal analysis by finite element method (FEM) to obtain FRF during machining thin-walled plate. The result showed that simulation result has good enough agreement to experimental result with slight differences caused by the assumed boundary conditions in the FEM process. This approach can be used to reduce the use of hammering tests and can be used to get FRF of multi stage working.

Effects on the distortion of Inconel 718 components along a hybrid laser-based additive manufacturing process chain using laser powder bed fusion and laser metal deposition

The combination of laser powder bed fusion (LPBF), known for its geometrical freedom and accuracy, and the nozzle-based laser metal deposition process (LMD), known for its high build-up rates, has great potential to reduce the additive manufacturing times for large metallic parts. For the industrial application of the LPBF-LMD hybrid process chain, it is necessary to investigate the influence of the LMD process on the LPBF substrate. In addition, the build plate material also has a significant impact on the occurrence of distortion along the additive manufacturing process chain. In the literature, steel build plates are often used in laser-based additive manufacturing processes of Inconel 718, since a good metallurgical bonding can be assured whilst reducing costs in the production and restoration of the build plates. This paper examines the distortion caused by LMD material deposition and the influence of the build plate material along the hybrid additive manufacturing process chain. Twin cantilevers are manufactured by LPBF and an additional layer is subsequently deposited with LMD. The distortion is measured in the as-built condition as well as after heat treatment. The effect of different LMD hatch strategies on the distortion is determined. The experiments are conducted using the nickel-base alloy Inconel 718. The results show a significant influence of LMD path strategies on distortion, with shorter tool paths leading to less distortion. The remaining distortion after heat treatment is considerably dependent on the material of the build plate.

Numerical simulation of manufacturing process chain for pearlitic and bainitic steel rails

Computer system for the design of technology of the manufacturing of pearlitic and bainitic rails was presented in this paper. The system consists of the FEM simulation module of thermal–mechanical phenomena and microstructure evolution during hot rolling integrated with the module of phase transformation occurring during cooling. Model parameters were identified based on dilatometric tests. Physical simulations, including Gleeble tests, were used for validation and verification of the models. In the case of pearlitic steels, the process of subsequent immersions of the rail head in the polymer solution was numerically simulated. The objective function in the optimization procedure was composed of minimum interlamellar spacing and maximum hardness. Cooling in the air at a cooling bed was simulated for the bainitic steel rails and mechanical properties were predicted. The obtained results allowed us to formulate technological guidelines for the process of accelerated cooling of rails.