Ildikó Maňková

Finite Element Simulation of Cutting Forces in Orthogonal Machining of Titanium Alloy Ti-6Al-4V

In this paper, a Lagrangian finite element-based machining model is applied in the simulation of cutting forces in two-dimensional orthogonal cutting of titanium Ti-6Al-4V alloy. The simulations were conducted using 2D Finite Element Method (FEM) machining simulation software. In addition, the cutting experiments were carried out under the different cutting speed, feed and tool geometry (rake angle, clearance angle and cutting edge radius). The effect of cutting speed, feed and tool geometry on cutting force were investigated. The results obtained from the finite element method (FEM) and experimental studies were compared.

Effect of Honing Parameters on Generated Surface Quality of Cylinder Liner within Automotive Engine Production

One of the key parameter in evaluation of cylindrical surface quality of the engine liners is surface roughness. A large number of process factors affecting a final surface topography, which has direct impact on fuel consumption and CO2 emission. A suitable choice of honing conditions can results not only to better surface quality, but it can contributes to reducing of environmental impacts in automobile transport. Twelve different engine cylinder liners were machined in various combinations of cutting parameters. Experimental testing was realised on real production machine tool, where process factors were cutting speed, machining allowance and stone pressure of honing tool. All factors have 4 levels and parameters of surface roughness CR, CF, CL were selected as a variables and suitable indicators for surface quality assessment. The results show that influence of the tool stone pressure on honed surface is more significant than effect of cutting speed. Effect of machining allowance is negligible as well.

Sampling Based Assessment of the Free-Form Milling Strategies

In this paper, author introduce common needs of increasing surface quality in tool making, a sort of products manufactured by free form milling technology. Principles of the free-form surface decomposition into measurable samples are presented and that is a method of combining CAD modeling with design of sampling objects. Sampling objects are classed both according to their measurability and applied milling strategy. Authors verify experimentally their sampling approach for three milling strategies applied in surface finishing operations while free-form surfaces are investigated in terms of their signed radii. Verification of proposed approach is based on statistical distribution of the measured surface roughness data.

Modelling and Analysis of Relationship between Cutting Parameters Surface Roughness and Cutting Forces Using Response Surface Methodology when Hard Turning with Coated Ceramic Inserts

Experimental research and modeling in the field of turning hardened bearing steel with hardness of 62 HRC using TiN coated mixed oxide ceramic inserts is presented. The main objective of the article is investigation the relationship between cutting parameters (cutting speed and feed rate) and output machining variables (surface roughness and cutting force components) through the response surface methodology (RSM). The mathematical model of the effect of process parameters on the cutting force components and surface roughness is presented. Moreover, the influence of TiN coating on above mentioned variables was monitored. The design of experiment according to Taguchi L9 orthogonal matrix (32) was applied for trials. Pearson´s correlation matrix was used to examine the dependence between the factors (f, vc) and the machining variables (surface roughness and cutting force components). The results show how much surface roughness and cutting force components is influenced by cutting speed and feed in hard turning with coated ceramics.

Adaptive Control System to Assist the Surface Workpiece Quality when Drilling

Article deals with design of adaptive control system for drilling process of aerospace critical components. The system proposed in this paper is directed towards real the time control of surface roughness parameter Ra. Proposed model for monitoring and control consists of surface roughness prediction system and decision making subsystem. The artificial neural network was employed to calculate surface roughness parameter Ra through of process monitoring indices such as torque Mz, force Fz, power P and cutting conditions feed f, cutting speed vc. Test samples were nickel based super alloy Udimet 720 used as a basic constructional material of discs for gas turbine engines.

TRIBOLOGICAL AND REFRACTORY PROPERTIES OF TiAl3 INTERMETALLIC ALLOY

Substrates of Ti-based coatings were investigated regarding wear resistance and refractoriness. Substrates with and without the TiAl3 coating formed by the ion plating method with evaporation of Al are considered. Additionally, the paper briefly presents principles of kinetics of the formation of the TiAl3 coating.

Evaluation of Relationship between Cutting Parameters and Torque in Hole Making of Titanium Alloy

In terms of machinability are titanium alloys classified in the group of difficult to cut materials. The main factors determining this status are limited tool life, high generated cutting forces (torque) and temperature in cutting zone caused by low thermal conductivity as well as chemical reactivity with cutting tool. Solid carbide drills still remain as preferred choice in hole making process when machining Ti6Al4V alloy. Besides cutting conditions, tool and cutting edge geometry significantly affect the value of torque. Reduction of process energy requirements can be achieved by appropriate optimization of these parameters. Mathematical model describing influence of cutting speed, feed rate, clearance angle and cutting edge radius on investigated variable with high reliability coefficient (R2=96.72%) was found. Drilling experiments were designed and carried out using Taguchi orthogonal array L16.

Types of Tool Wear of AlTiN Coated Cutting Insert after Machining of Weld Overlay

Authors of the paper present different types of tool wear after machining of weld overlay with AlTiN cutting insert. Welded layer was created on roller made from S355J0 steel by Open Arc (OA) method also referred as Metal One Gas (MOG). Various forms of tool wear were documented by optical microscope. Microchipping of cutting edge, built up edge (BUE) and flank wear were identified on examined round insert in rough turning of hard cladding.

Influence of Cutting Parameters and Tool Geometry on Thrust Force Behavior in Drilling Ti6Al4V

Titanium alloy Ti6Al4V represents one of the most frequently used alloys in medical as well as in aerospace industry and is considered as a difficult to cut material. In this paper, cutting experiments within throughput drilling were carried out under the varying cutting speed, feed and tool geometry (cutting edge radius and clearance angle). The effects of cutting speed feed and tool geometry on thrust force in drilling Ti6Al4V alloy were investigated applying design of experiment (DoE) according to Taguchi plan L16. The effect of above mentioned parameters was investigated through analysis of the S/N ratios (smaller is better) and ANOVA analysis. All analyses were performed using statistical software Minitab and Matlab. In the case of thrust force, the feed is the main influencing factor, followed by cutting speed, cutting edge radius and clearance angle.

Tool Wear and Surface Roughness Evolution in Hole Making Process of Inconel 718

The paper focuses on tool wear and surface roughness indicators evaluation associated with hole making of nickel based super alloy Inconel 718 widely used in aero engine industry. Within study of tool wear and surface integrity, series of experimental tests were performed on an Inconel 718 specimen. Special attention was paid to ensure that the cutting conditions correspond to the industrial practice. Two steps of hole making sequence consists of a drilling process applying a twist drill that removes most of the stock. This operation is followed by a second machining process, typically applying a face – cutting finisher (reamer), which removes an additional (radial) stock between 0.1 mm to 0.25 mm per side. Tool wear appeared predominantly as flank wear VBmax and evolution of surface roughness Ra and Rz has a similar trend for drilling and finishing.