Milling Temperature Research Articles

Analysis of the cooling performance of Ti–6Al–4V in minimum quantity lubricant milling with different nanoparticles

Minimum quantity lubricant milling (MLQM) with nanofluids is one of the main processing methods used in sustainable green manufacturing. Nanoparticles can drastically enhance the heat transfer ability of metalworking fluids. Thus, nanofluids modified with different nanoparticles have important applications as milling coolants. Nevertheless, few studies have investigated the influence of different nanoparticles on the cooling mechanisms of nanofluids. An experimental study was conducted to explore the cooling performances of different nanofluids in the MQLM of Ti–6Al–4V. Cottonseed oil was used as the nanofluid base and was modified with six different nanoparticles at the mass ratio of 1.5%. Cooling performance was evaluated with several milling parameters, including milling force, instantaneous temperature, and surface roughness, which was represented as the arithmetic average height (Ra) of the workpiece surface. The microtopography of the final milled samples was also examined. Results demonstrated that the mean of the milling force peak in the X direction under milling with SiO2 nanofluid was 436 N, which was lower than that under milling with MoS2 nanofluid (445.5 N). The lowest milling temperature was obtained with SiO2 nanofluid. This result indicated that SiO2 nanoparticles had the strongest cooling capacity. Workpiece temperature rapidly decreased to a low value under milling with SiO2 and Al2O3 nanofluids. The most drastic temperature drop was observed in MQLM with SiO2 nanofluid, followed by that in MQLM with Al2O3 nanofluid. The lowest Ra value was obtained under milling with Al2O3 nanofluid (0.59 μm), followed by that obtained under milling with SiO2 nanofluid (0.61 μm). The Ra value acquired under milling with Al2O3 nanofluid was 66.7% lower than that of acquired under milling with pure cottonseed oil. Given that Al2O3 and SiO2 nanoparticles demonstrated the best cooling performance, they are highly suitable as additives for the base oil.

On modelling of cutting force and temperature in bone milling

Cutting force and temperature are the key factors to be controlled during the orthopaedic surgery which could result in mechanical damage and necrosis of the bone tissue. Mechanistic modelling of the bone cutting process is expected to be an efficient method to understand and control these process challenges. However, due to the special structure and properties of the bone tissue (consist of osteon fibres and interstitial lamellae matrix), the conventional metal cutting models are not applicable in bone cutting process. This paper presents a novel cutting force and temperature mechanistic models for milling of bone. A cutting stress model of bone material was developed which takes into account its anisotropic characteristics based on the orthogonal cutting data. The cutting force coefficients are predicted incorporating the osteon orientation, tool geometry and edge effect with unified mechanics of cutting approach. Furthermore, a model of the induced cutting temperature based on heat flux developed during the process was proposed to predict the temperature distribution on bone cut surface. The experimental results showed a better consistency with the proposed model compared with the conventional Johnson-Cook model under different cutting conditions. A necrosis (potential cell injury from thermal effect) penetration depth was also proposed to evaluate the extent of thermal damage of bone tissue by the developed models. The proposed model can be used to assist the robotic surgery, to optimize the cutting parameters as well as to guide the orthopaedic tool design.

Analytical prediction of temperature in laser-assisted milling with laser preheating and machining effects

An analytical predictive model for temperature in laser-assisted milling considering both laser preheating temperature and machining induced temperature rise is proposed. The preheating temperature at top surface is predicted first by considering the heat generation from laser and convection. The heat generation rate is described by Gaussian equation. Within the material, heat conduction is considered with isothermal boundary conditions at side and bottom surfaces. The machining temperature is considered by transferring the milling configuration to orthogonal cutting at each instance. The shearing heat source and secondary rubbing heat source are included for machining temperature prediction. The heat source is calculated from the cutting or plowing forces, and a mirror heat source method is applied to predict temperature rise through integration. The proposed model is validated through experimental measurements on silicon nitride ceramics and Ti-6Al-4V alloy. The proposed predictive model matches the experimental measurements with less than 7.1% difference at laser spot and 5.2% difference in front of the cutting zone with computation time less than 15 s. The model is valuable for providing a fast, credible, and physics-based method for the prediction of temperature in laser-assisted milling of various materials. The overall temperature distribution is accurately calculated by predicting laser preheating temperature and machining induced temperature rise.

Simulation and Experiments on Cutting Forces and Cutting Temperature in High Speed Milling of 300M Steel under CMQL and Dry Conditions

The effects of cryogenic minimum quantity lubrication (CMQL) on cutting forces and cutting temperature are analyzed in high speed milling of 300M steel. The influences of cutting parameters on cutting forces and cutting temperature are predicted by analogue simulation. Based on single-factor comparative test, the variation laws of cutting forces F and cutting temperature T with cutting parameters are studied in high speed milling of 300M steel under dry and CMQL conditions. Under the condition of CMQL, the influence of cutting parameters (cutting speed v, feed per tooth fz, cutting depth ap and cutting width ae) on cutting forces and the cutting temperature are analyzed by orthogonal test, and the prediction models of cutting forces and cutting temperature are established. The results show that CMQL condition can effectively reduce cutting forces and cutting temperature in the cutting process. Under the condition of CMQL, the cutting depth on the cutting forces is most significant, and the cutting speed has the greatest influence on the cutting temperature. The prediction model of cutting forces and cutting temperature is established, which can be a valuable reference for actual machining.

Tool wear of corner continuous milling in deep machining of hardened steel pocket

Pocket molds are widely applied, whose pockets usually contain many transition corners. The machining efficiency of pocket mold can be improved significantly through deep milling. However, tools are subject to quick wear and damage during corner deep milling. Corner rounding along tool path by different approaches has great influence on the tool wear in deep milling of hardened steel pocket mold. Therefore, conducting related researches on tool wear is of practical significance. Firstly, continuous cutting pocket molds were designed for typical corners of different corner rounding approaches as per the basic theory of tool engagement angle in milling, and then hardened steel was subject to deep milling and the tool was inspected and analyzed; afterwards, tool wear process and mechanism, etc. were studied. The results showed that during the deep milling of hardened steel, adhesion, oxidation, and diffusion wear appeared gradually since the stabilization of tool wear and further aggravated along with the cutting process, which led to wear and peeling of coating as well as highly possible tool damage like tipping and chipping of tool nose in later period. It was easy to generate high tool-chip interface temperature and great tool load in the high-speed deep milling of hardened steel with small corner rounding radius. In this case, the cutting edge was under considerable thermal fatigue and mechanical shock and thus subject to extensive abrasion wear, adhesion wear, and diffusion wear. The tool wear could be reduced notably by increasing the corner rounding radius.

The Mechanical Properties and In Vitro Biocompatibility of PM-Fabricated Ti-28Nb-35.4Zr Alloy for Orthopedic Implant Applications.

A biocompatible Ti-28Nb-35.4Zr alloy used as bone implant was fabricated through the powder metallurgy process. The effects of mechanical milling and sintering temperatures on the microstructure and mechanical properties were investigated systematically, before in vitro biocompatibility of full dense Ti-28Nb-35.4Zr alloy was evaluated by cytotoxicity tests. The results show that the mechanical milling and sintering temperatures have significantly effects on the density and mechanical properties of the alloys. The relative density of the alloy fabricated by the atomized powders at 1500 °C is only 83 ± 1.8%, while the relative density of the alloy fabricated by the ball-milled powders can rapidly reach at 96.4 ± 1.3% at 1500 °C. When the temperature was increased to 1550 °C, the alloy fabricated by ball-milled powders achieve full density (relative density is 98.1 ± 1.2%). The PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C can achieve a wide range of mechanical properties, with a compressive yield strength of 1058 ± 35.1 MPa, elastic modulus of 50.8 ± 3.9 GPa, and hardness of 65.8 ± 1.5 HRA. The in vitro cytotoxicity test suggests that the PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C has no adverse effects on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties and the net-shape manufacturability makes PM-fabricated Ti-28Nb-35.4Zr alloy a low-cost, highly-biocompatible, Ti-based biomedical alloy.

Influence of sintering temperature on the structural, electrical and microwave properties of yttrium iron garnet (YIG)

This study investigates the structural, electrical and microwave properties of yttrium iron garnet (YIG) which focuses on the parallel evolving relationship with their dependence on the sintering temperature. The iron oxide obtained from the steel waste product (mill scale) was used to synthesize YIG. The raw mill scale underwent the milling and Curie temperature separation technique to produce high purity iron oxide powder which is the main raw material in preparing and fabricating YIG through high energy ball milling (HEBM) process. Microstructural features such as amorphous phase, grain boundary, secondary phase and intergranular pores contribute significantly to the additional magnetic anisotropy and demagnetizing fields, affecting the electric and microwave properties accordingly. The increment in electrical resistivity and decrement in linewidth while the microstructure was evolving is believed to be a strong indicator of improved phase purity and compositional stoichiometry.

Simulation Analysis of Milling Temperature and Milling Force of New Cold Saw Blade Milling Cutter

Based on finite element method, cold sawing temperature field is analyzed theoretically. With AdvantEdge finite element physics simulation software platform, we used the single-factor method to simulate and analyze the milling temperature and milling force that are caused to change with the rake angle, relief angle, feed per tooth and rotating speed. It concluded that rake angle, feed per tooth, and rotating speed have great influences on temperature field of new cold saw blade milling cutter. Rake angle and feed per tooth have great influences on the force of the new cutter. Relief angle has little influence on MT&MF. Using the simulation results, the new cutter is compared with traditional hot saw. The maximum milling temperature achieved during milling is 318.09 °C for the new cutter, with above 750 °C for the counterpart.

Experimental study on cutting force and cutting temperature in high speed milling of hardened steel based on response surface method

The hardness and wear resistance of hardened steel are high. It is widely applied in the field of automobile and die manufacturing field. In order to get a reasonable cutting plan, the influence of cutting parameters on milling force and temperature is explored in the process of high speed milling of hardened steel. High speed milling experiment with different machining parameters is carried out and centre composite response surface method is applied. The regression model of cutting force and cutting temperature are established in the process of high speed milling of hardened steel. The significance of the milling parameters on the force and temperature under the interaction and its reasons are analysed. Analysis of variance is performed to evaluate the significance of regression. It can effectively predict the milling force and milling temperature in the process of high speed milling of hardened steel. It provides the basis for the reasonable choice of cutting parameters. From the processed surface quality to verify that cutting parameter is selected based on prediction model and the significant analysis of milling force and temperature is more reasonable. [Submitted 25 December 2016; Accepted 29 August 2017]

Research on milling temperature measuring tool embedded with NiCr/NiSi thin film thermocouple

In order to measure the milling area temperature in-situ, the milling tool embedded with NiCr/NiSi thin film thermocouple (TFTC) is prepared. TFTC capable well temperature performance is embedded on the tool tip by successively depositing SiO2 insulating film, NiCr/NiSi thermoelectric film, and SiO2 protective film. Surface morphology and thin film properties are confirmed to achieve expectation by means of TEM and SEM. Imitation reflects that TFTC abrasion has minor effect on dynamic and static characteristic. The in-situ milling area temperature is successfully detected by TFTC temperature measuring tool in field test.

Experimental study on cutting force and cutting temperature in high speed milling of hardened steel based on response surface method

Experimental study on cutting force and cutting temperature in high speed milling of hardened steel based on response surface method

Investigation of Tool Core Temperature and Mechanical Tool Load in Milling of Ti6Al4V

The special properties of titanium and titanium alloys, such as their high strength-to-weight ratio, their corrosion resistance, and their biocompatibility are of high importance for aerospace, medical and other industrial applications. However, components made of these difficult-to-cut materials entail major challenges for machining processes. High thermo-mechanical tool load results in rapid tool wear, and the already significant machining costs are further increased by premature tool exchange to avoid tool breakage, damaging the valuable workpieces. Both, tool wear progress and risk of tool breakage can be reduced by gaining extensive knowledge about the thermo-mechanical tool load over the tool life time. In this paper, the influence of different machining parameters on the end milling tools’ core temperature and the resulting active force affecting the tool are investigated over tool life time. To measure thermal and mechanical tool loads, an adapted sensory tool holder was used. The results show a strong interdependence between tool load, tool core temperature, machining parameters and tool wear.

Comparison of Tool Core Temperature and Active Force in Milling of Ti6Al4V under different Cooling Conditions

Difficult-to-cut materials, such as titanium- and nickel base alloys, are of great importance for the aerospace industry. However, they entail major challenges for machining processes, due to the high thermo-mechanical tool load. To meet these challenges, various lubrication and cooling strategies have been developed, but their effect on the load collective has not been sufficiently investigated. In this paper, the influence of different lubrication/cooling strategies on the end milling tools’ core temperature and the resulting active force affecting the tool while milling Ti6Al4V are investigated. Therefore, an adapted sensory tool holder with wireless data transmission was used.

Nanosized tetragonal β-FeSe phase obtained by mechanical alloying: structural, microstructural, magnetic and electrical characterization.

Nanocrystalline tetragonal β-FeSe phase was prepared mechanochemically using ball milling procedures in an inert atmosphere, starting from FexSe powder mixtures with x = 1.00, 1.25 and 1.50, with x = 1.25 and 1.50 leading to more than 93% of pure phase after annealing at 400 °C for 1 hour under vacuum. X-ray powder diffraction provides information on phase formation and phase transitions with milling time and temperature. The Rietveld method was used to refine the crystal structure, including the z coordinate of Se and occupancies, to determine the microstructure and to assess the amount of contaminant phases observed. Lattice contraction is found in the ab-plane more than along the c-axis, the small average size of crystalline domains (<22 nm) and the high microstrain (>1%) indicate the formation of highly strained nanoparticles. Magnetic and electrical characterization showed a poor superconductivity at 4 K and semiconducting properties only for thermally treated samples. These observations are explained by the presence of ferromagnetic impurity phases (residual Fe, hexagonal δ-FeSe phase and monoclinic Fe3Se4), but other effects caused by the mechanochemical synthesis must be considered, such as small average size, large/non-uniform size distribution and high microstrain of the nanosized tetragonal β-FeSe phase. The increase of the β-FeSe phase content with increasing storage time (ageing) above a few days to months in air, at RT and in the dark was observed for all as-milled samples. Preliminary data on the ageing effect are shown while a systematic study on this is in progress and will be presented elsewhere.

Force and temperature modelling of bone milling using artificial neural networks

The force and temperature of bone milling depends on a large number of parameters pertaining to the bone tissue and cutting tools. In the current literature, there is a lack of information on bone milling for cancellous tissues. In this paper, we use the artificial neural network (ANN) methodology to develop appropriate force and temperature models based on real experimental measurement data of bone milling on artificial tissues with cancellous properties. The models estimate the milling force and temperature as a function of feed rate and spindle speed. Two temperature models are considered, the bur temperature and the fresh-milled bone surface temperature. A full factorial design of experiment (DOE) is used to collect the necessary data for developing and validating the models. A very good agreement between the estimated and the experimental milling forces and temperature is found. The established models are useful for real-time bone milling optimization and control.

Minimization of cutting force, temperature and surface roughness through GRA, TOPSIS and Taguchi techniques in end milling of Mg hybrid MMC

Present study investigates the effect of material and machining parameters on cutting force, surface roughness and temperature in end milling of Magnesium (Mg) Metal Matrix Composite (MMC) using carbide tool. Mg hybrid composite was fabricated by reinforcing Cathode Ray Tube (CRT) panel glass, an intensifying E-waste and Boron Nitride (BN) particles through powder metallurgy method. The milling experiments were conducted based on L27 orthogonal array designed by considering CRT glass particle size and weight percentage, tool diameter, speed, feed and depth of cut as input process parameters. Multi objective optimization was done through Grey Relational Analysis (GRA) and Techniques for Order Preferences by Similarity to Ideal Solution (TOPSIS). Both of the techniques provided a similar optimum parameter condition i.e. 10 µm particle size, 5% reinforcement, 8 mm diameter tool, 710 rpm speed, 20 mm/min feed and 0.5 mm depth of cut that outcomes in 139.48 N in-feed force, 63.92 N cross-feed force, 42.6 N thrust force, 68.96 °C temperature and 0.198 µm surface roughness. ANOVA is performed to identify significance and also the effect of each process variables on response parameters. Though all the parameters were found to be significant, reinforcement weight% and particle size affects the response parameters as that of machining parameters whereas speed turned to be the least significant factor.

Experimental and numerical investigations of machining depth for glass material in electrochemical discharge milling

Electrochemical discharge milling (ECDM) is one of the best alternatives for microchannel fabrication in non-conducting materials. The ECDM is a complex process which makes difficult the prediction of the material removal rate (MRR). The prediction of the machining depth in the microchannel fabricated with electrochemical discharge milling (ECD milling) was an interesting research subject. This study attempts to present a thermal model based on the finite element method (FEM) to predict the machining depth in ECD milling. The input parameters of the FEM model were calculated based on different machining conditions such as machining voltages and electrolyte concentrations. The model is validated by conducting experiments in the same ECD milling conditions. In the FEM model, the different criteria for the material removal temperature (Teq) were applied and the machining depths were calculated. The comparisons of the results show that there is good agreement between FEM models and experimental results when the Teq were selected between 600 to 850°C. It seems that the softening Littleton point of 720°C is a good suggestion as a criterion for the material removal temperature in ECD milling.

An experimental study on cutting temperature and burr in milling of ferritic stainless steel under MQL using nano graphene reinforced cutting fluid

An experimental study on cutting temperature and burr in milling of ferritic stainless steel under MQL using nano graphene reinforced cutting fluid

An investigation of tool temperature in end milling considering the flank wear effect

In this paper, the tool temperature in end milling considering the flank wear effect was investigated by theoretical and experimental method. Theoretically, a new analytical model was developed to predict tool temperature in end milling. The new analytical model takes into account the flank wear effect, complex tool geometry and dynamic heat flux and partition in end milling. In order to tackle complex tool geometry, the tool is axially discretized into numerous tool differential elements. Based on heat source method, the heat transfer of each tool differential element is analyzed independently to model the temperature of each tool differential element. Then superpose the temperature of each tool differential element is to work out the total tool temperature. Experimental, according to single factor design, the end milling operations of Ti6Al4V were conducted with fresh and worn tool to determine the effect of flank wear on tool temperature and to validate the theoretical model. The experimental validation indicates that the new temperature model is able to predict the sharp and worn tool temperature in end milling accurately. The effect of flank wear on tool temperature, cutting force and heat partition on flank face is evident. At same flank wear, the tool temperature and cutting force primarily depend on feed per tooth and secondly on cutting speed. The heat partition on tool-chip interface increases with the increase of feed per tooth, but decreases when the cutting speed increases. There is an inverse trend in variation of heat partition on flank face compared with heat partition on tool-chip interface.

Influence of Li:Fe molar ratio on the performance of the LiFePO4/C prepared by high temperature ball milling method

LiFePO4/C cathode material for lithium ion battery was prepared with lithium dihydrogen phosphate, iron oxide, and glucose monohydrate as raw materials. In an attempt to improve the electrochemical performance, the influence of Li:Fe molar ratio was investigated in this paper. Experimental results showed that the best electrochemical performance of LiFePO4/C was reached in this study, when Li:Fe molar ratio was 1.03:1 synthesized preheated ball milling temperature at 300°C for 1h, and then ball milling temperature at 650°C for 8h, at the rates of 0.1, 0.5, 1.0, 2.0, 5.0 and 10C, the initial discharge capacities of 157 (±2), 151 (±2), 144 (±2), 136 (±2), 119 (±2), 102 (±2) mAhg−1, respectively. Moreover, after 50cycles, at rate of 0.1C, the capacity of LiFePO4/C sample was 155 (±2) mAhg−1, and its capacity retention rate achieve 99.5%.