Impact of Cutting Parameters on Cutting Force of AISI 410 and AISI 420 MSS during CNC Dry Milling

A CNC dry milling experiment was conducted for the machining parameter optimization of two grades of Martensitic Stainless steel (MSS). Optimization is done by employing Taguchi method (S/N ratio and ANOVA). The specimens used are MSS grades 410 and 420.The experiments were designed by employing L9 orthogonal array for 3 levels of feed and spindle speeds. The impact of these parameters on cutting force was analyzed. The analysis reveals that spindle speed constitute the maximum impact on cutting force for both MSS grades. Optimum cutting parameters are obtained at 30 mm/min (feed rate) and 1500 rpm (spindle speed). Due to higher Chromium and Carbon content in AISI 420 MSS resulted higher cutting force values compared with AISI 410 MSS. Optimum values of cutting parameters are estimated for improving productivity and quality. The predicted values at optimal conditions are estimated. The results indicate a good conformity with the outcome of experiment.

DEVELOPMENT AND TEST OF FREQUENCY SUBSECTION REGULATION SYSTEM FOR COMBINE HARVESTER HEADER CUTTER

Aiming at the problems that the cutter frequency of combine harvester is difficult to be adjusted adaptively with the forward speed, and that the missed cut or repeated cut may cause the harvesting loss to increase and the operation effect to fluctuate greatly, the system is designed to regulate the cutter frequency of combine harvester by sections. By constructing the cutter trajectory equation, the influence of the relationship between the forward speed of the harvester and the cutting frequency on the cutting area is analyzed, and the optimum cutting frequency range at different operating speeds is determined. The results show that the error between the actual cutting frequency and the desired frequency of the cutter is less than 0.8Hz, and the maximum relative error is less than 8.6%; the average steady-state adjustment time of the system is 1.3s when the input cutting frequency of the device changes abruptly. The research class provides technical support for the improvement of the combine harvester handling system and the increase of the machine automation level.

FE-Simulation Based Design of Wear-Optimized Cutting Edge Roundings

The performance of cutting tools can be significantly enhanced by matching the cutting edge rounding to the process and material properties. However, the conventional cutting edge rounding design is characterized by a significant number of experimental machining studies, which involve considerable cost, time, and resources. In this study, a novel approach to cutting edge rounding design using FEM-based chip formation simulations is presented. Based on a parameterized simulation model, tool temperatures, stresses and relative velocities can be calculated as a function of tool microgeometry. It can be shown that the external tool loads can be simulated with high agreement. With the help of these loads and the use of wear models, the resulting tool wear and the optimum cutting edge rounding can be determined. The final experimental investigations show a qualitatively high agreement to the simulation, which will enable a reduced effort design of the cutting edge in the future.

Influence of the moisture content and speed on the cutting force and energy of tannia cormels

This study investigated the influence of the moisture content and speed on the cutting force and energy of tannia cormels using the response surface methodology (RSM). The moisture content and cutting speed were varied over five levels each [95.79, 113.68, 136.68, 168.42, 242.11% moisture content (dry basis) and 10, 15, 20, 25, 30 mm×min^–1, respectively]. The highest and lowest cutting forces were 114.09 and 63.99 N at the corresponding moisture contents of 168.42 and 113.68% and at cutting speeds of 10 and 20 mm×min^–1, respectively. The highest and lowest cutting energies of 0.92 and 0.49 J were both obtained at a 136.68% moisture content, at the 10 and 20 mm×min^–1 cutting speeds, respectively. The regression models for predicting the cutting force and energy as a function of the cutting speed and moisture content showed that there was no linear relationship between the investigated properties and the independent variables considered which could be attributed to the non-homogeneous nature of tannia cormels. The optimum cutting force and energy were 72.89 N and 0.60 J, respectively, at a 95.79% moisture content and a 22.33 mm×min^–1speed with a desirability of 0.80. These findings could serve as a guide for the development of chipping and cutting machines for tannia cormels.

Mitigating Cutting-Induced Plasticity Errors in the Determination of Residual Stress at Cold Expanded Holes Using the Contour Method

Background The split sleeve cold expansion process is widely used to improve the fatigue life of fastener holes in the civil and military aircraft industry. The process introduces beneficial compressive residual stresses around the processed hole, but uncertainties remain about the character of the stress field immediately adjacent to the bore of the hole. Objective The primary objective of this study was to implement the contour method with minimising error associated with cutting-induced plasticity to provide detailed and reliable characterisation of the residual stress introduced by the split sleeve cold expansion process. Methods A systematic FE study of plasticity effects by simulating different contour cutting strategies (a single cut, two sequential cuts and a 6-cut sequence) for a cold expanded hole in an aluminium alloy coupon was conducted. The identified ‘optimum’ cutting strategy was then applied experimentally on coupons containing a hole that had been processed to 3.16% applied expansion. Results The FE study of different cutting simulations show that the locations of the stress error is consistent with the location where cutting-induced plasticity accumulated and that the magnitude and locations of stress re-distribution plasticity can be controlled by an optimised cutting strategy. In order to validate this hypothesis a high quality contour measurement was performed, showing that accurate near bore stress results can be achieved by the proposed 6-cut approach that controls cutting induced plasticity. Conclusions The present work has demonstrated that detailed FE simulation analysis can be a very effective tool in supporting the development of an optimum cutting sequence and in making correct choices of boundary conditions. Through optimizing these key aspects of the cutting sequence one is much more likely to have a successful, low error contour residual stress result.

Efficiency of technology use for high-speed end milling of hardened parts of GTE fuel equipment

There are shown results of high-speed end milling experimental researches of critical hardened steel parts in fuel control equipment of modern aircraft gas turbine engines (GTE) with the purpose of optimum cutting mode definition ensuring the roughness Ra ≤ 0.63 mkm for the surface worked and deviation from the plane not more than 0.015 mm. The empirical mathematical models of high-speed milling are obtained and optimum cutting modes are defined.

Single-stage support of friction surface wear intensity at edge processing

On the basis of the investigations carried out there are offered theoretical dependences for the determination of wear intensity with regard to cutting modes with edge tools. They allow defining optimum cutting modes to ensure the required intensity of friction surface wear at edge processing.

Effect of Minimum Quantity Lubrication System for Improving Surface Roughness in Turning Operation

Due to increase in temperature at the cutting zone, the tool wear and surface roughness along with the non-uniform chip formation and the dimensional deviation of the job by using the conventional cutting fluid, the machining operation experts have directed their concentrations in order to achieve a smooth machining operation by using minimum quantity lubrication (MQL). As a consequence, numerous efforts can be seen for not only having the optimum cutting parameters but also other parameters that enhance the product quality and the surface roughness. In this regard, relevant experimental and numerical data outcomes not only MQL but also conventional cutting fluid (CCF) in the turning operation of 50HRC steel has been investigated experimentally. It is revealed that the surface roughness becomes optimal and significantly reduced for the condition of MQL with that of dry and conventional flood lubrication.

Experimental Analysis of a Grinding Wheel by Increasing Multiple Passes in Dressing

When sharpness of grinding wheel becomes dull, a dressing is an operation performed because of glazing and loading, dulled grains and chips are removed (crushed or fallen) with a proper dressing tool to make sharp cutting edges and simultaneously, make recesses for chips by properly extruding to grain cutting edges. The basic dressing operation consists of removal of grains and swarfloaded, generation and exposure of the new cutting edges on the cutting surface of the grinding wheel. The former is obtained by digging out the swarf and the latter is achieved by fracturing the existing abrasive grains and allowing desired protrusion of abrasive particles on the cutting surface. Both of the above operations are carried out using a diamond dresser (3 carat). A part of this work focuses on finding the optimum dressing parameters (depth of cut of the dresser and the number of passes) which gives optimum cutting condition for grinding using conventional method of grinding using diamond dresser, Water Jet Machine and Abrasive Water Jet Machine. The trial run on the conventional machine with different parameters was performed. The results obtained prove the possibility of using directly in the industrial practices.