Cutting Edge Micro Research Articles

A Study on Strategic Positioning for Open Innovation Platform (OIP) of TSMC

The foundry business plays a critical role on system chip value chain due to a high demand for micro processing fabrication. The TSMC, a creator of foundry business, has shown a strong leadership of global foundry business. A sustainable growth of TSMC is deeply concerned with the ‘Open Innovation Platform (OIP).’ This study analyzed the competitiveness of OIP from strategic positioning perspective. As the analysis result, firstly, the activity system map of OIP shows that six types of alliances work as a systematically connected whole system to support the fabless firms rather than a simple combination. Secondly, the product variety based positioning of OIP is related with five technology platforms of TSMC that cover almost all the fabless customers of advanced IT products & services. Thirdly, the customer needs based positioning of OIP comes from the operation of various fabs covering not only the cutting edge micro processing under 7 Nano as of 2023 but also the general level of processing and legacy one. Fourthly, the access based positioning of OIP is concerned with making fabless firms just focus on the ‘Know-what’ rather than the ‘Know-how’ or ‘Know-where’ on the system chip value chain.

Manufacturing and preparation of micro cutting tools: influence on chip formation and surface topography when micro cutting titanium

Cutting edge preparation is widely used in conventional cutting processes. It stabilizes the cutting edge and is done to improve coating adhesion. However, the preparation of the cutting edge is accompanied by an increase in cutting edge roundness. This rounding results into larger effective negative rake angles, especially at small undeformed chip thicknesses, as they prevail in micro and ultraprecision processes. In this paper, the influence of the cutting edge micro geometry at very small undeformed chip thicknesses is investigated. A sharp, a rounded and a chamfered cutting edge are manufactured and examined at undeformed chip thicknesses of 0.4 µm, 5.2 µm and 10.0 µm. The resulting chip formation, forces and surface quality are examined when orthogonal cutting commercially pure titanium, a material used for example for bio-applications.

Investigation on cutting edge preparation and FEM assisted optimization of the cutting edge micro shape for machining of nickel-base alloy

The productivity and the tool life of cutting tools are majorly influenced by the cutting edge micro shape. The identification of optimized cutting edges is usually based on empirical knowledge or is carried out in iterative investigation steps. This paper presents an approach to predict optimal cutting edge micro shapes with the aid of finite-element-simulations of the chip formation. The approach is investigated for the machining of the nickel-base alloy Inconel 718. The cutting edges are prepared by pressurized air wet abrasive jet machining. Utilizing this method, the prepared cutting edges have a certain profile, which is considered for the modelling. By applying a model for tool wear the influence of the cutting edge micro shape on the tool life span is estimated. Subsequently, a statistical modelling provides the prediction of the tool wear rate for any possible parameter set within the investigated range. This is used to find an optimized cutting edge profile that minimizes the tool wear. An experimental investigation concludes the optimization procedure.

Effect of cutting edge micro geometry on surface generation in ball end milling

Surface generation in machining processes is affected by a complex interaction between cutting edge and workpiece material, leading to surface artefacts, so that the surface topography deviates considerably from the kinematic one. This paper shows how to model such interaction, taking into account cutting edge topography, material deformation and cutting edge trajectory errors to achieve a reliable prediction of surface topography generation in ball end milling. The model is experimentally validated in upward raster ball end milling of copper and tool steel.

Surface integrity of turned laser-welded hybrid shafts

For applications like components of vehicle drives, e.g. drive shaft or motor shaft, the increasing amount of CO2 emission becomes a major challenge. Weight reduction of vehicle parts is one possibility to reduce CO2 emission. Therefore functionally adapted components must be designed in order to become smaller and lighter. Consequently monolithic material is not sufficient anymore, so there is a demand for tailored hybrid parts consisting of more than one material. Those tailored hybrid parts have to pass through a processing chain. There is the option of joining different materials in the hybrid part to meet the requirements. The discussed combination is a SAE1020-SAE5120 compound. Laser beam welding is an appropriate joining process due to its reduced heat influence, the resulting narrow welds and a low post-processing effort. Thus semi-finished products for the manufacturing of tailored hybrid shafts with graded properties can be produced efficiently. Further in the process chain there is the need for machining to reach an adequate level of accuracy of shape and dimension. Moreover the residual stress modification by the machining process has a deep impact on the lifespan of hybrid components. Therefore in this paper the machinability of the SAE1020-SAE5120 compound compared with a SAE1020-SAE1020 compound will be examined. The effect of cutting edge micro geometry on the surface and subsurface properties is analysed. Relationships between process forces, residual stresses and surface roughness are investigated. Metallographic cross sections and hardness measurements will show the connection between welded materials. The transition zone—the weld between the monomaterials—is the centre of attention for the investigations.

Simulation based analysis and optimisation of the cutting edge micro shape for machining of nickel-base alloys

The modification of the cutting edge micro shape by wet abrasive jet machining is utilized to increase the performance of cutting tools by means of productivity and tool life. However, for numerous cutting processes the optimal micro shape of cutting edges is still unknown. In this regard, the paper deals with a method to predict optimized cutting edge micro shapes using FE-Simulation. The method includes the consideration of the local process conditions like radius dependent cutting speeds in drilling processes depicted by the example of drilling a nickel-base alloy. In this paper first simulation analyses are compared to experimental investigations. In addition, predictions of the mechanical loads dependent on the applied cutting edge micro shapes are presented.

Quality of the Cutting Tool Microgeometry for Machining Aluminium Alloys

Modern cutting tools with high quality attributes are very important factors for companies that want to increase their production efficiency and product quality. Cutting tool properties include high durability, endurance and cutting power. Quality shapes and surfaces of cutting edge micro and macrogeometry are also important. This article deals with cutting edge microgeometry on sintered carbide end mill tools. Drag finishing technology is used for preparation of cutting edge microgeometry. Two process media are used during the experiment. Due to the different process media, the final surface quality will also be different. Nowadays, cutting edge preparation is one of the basic but inseparable parts of development and production of cutting tools. Microgeometry quality affects the behaviour of cutting tools during the machining process. The behaviour mainly includes cutting forces, friction and vibration. The impacts of drag finishing on the functional surfaces of the cutting tool are investigated in this article. An IFM G4 microscope is used for measuring the cutting edge microgeometry.

Influence of asymmetric cutting edge roundings on surface topography

For finishing operations in machining, hardened steel hard turning can compete with grinding operations by means of accuracy and productivity. In the past research focussed on the effect of process parameters and tool macro geometry on the resulting surface roughness. Recent investigations show, that the cutting edge micro geometry is an important factor to influence surface quality. The knowledge generated by new methods displays the importance of asymmetric cutting edge roundings on cutting forces, chip formation and tool life. It is known, that chip formation also affects the resulting surface quality. Therefore, this paper investigates the effect of asymmetric cutting edge roundings on the resulting surface roughness in hard turning of roller bearing inner rings. Cutting tests with differently shaped cutting edges and two different feed values are conducted. The resulting surface roughness is measured. The consequent surface quality is explained by geometric coherences between uncut chip thickness and stresses along the cutting edge and the effect of material side flow. It is found, that the cutting edge geometry and the resulting stress distribution around the cutting edge affects the generated surface quality.

Influence Of Procedure-Related Cutting Edge Micro Geometry Modification On The Production Quality When Milling Fibre Reinforced Plastics

The importance of carbon or glass fibre reinforced plastics in aviation and automotive industry has increased considerably over the last twenty years. The latest generation of commercial aircrafts for example exhibits a composite weight proportion of up to 50 %. To generate the final contour and to realize appropriate interfaces for following assembly processes, modern tools and manufacturing technologies are required to ensure high workpiece qualities. The combination of strength enhancing fibres, a ductile matrix and various laminate structures highly strains the cutting edge during the cutting process. For this field of application various cutting edge and tool geometries has been developed by several tool manufacturers to maximize wear resistant and shape accuracy. The wear mechanism and course of different cutting materials and its influence on workpiece quality during trimming of carbon and glass fibre reinforced plastics were analysed. It could be shown that an increasing tool wear does not cause necessarily low workpiece qualities. Additionally, the influence of different process parameters and strategies on the cutting edge micro geometry forming and the workpiece quality were analysed.

Wet Abrasive Jet Machining to Prepare and Design the Cutting Edge Micro Shape

Cutting edge preparation is utilized to increase the stability of cutting tools and to improve the adhesion strength of a subsequent coating. In this context wet abrasive jet machining with a robot guided system allows to prepare local tool areas and to realize a specific design of the cutting edge, as well as advantageous surface qualities. This paper is concerned with the requirements and challenges in preparing and designing the cutting edge micro shape using wet abrasive jet machining. Important factors of the process as well as resultant shapes and topography effects of the machined cutting edges are discussed.

Wear Behaviors of PCBN Tools in Interrupted Turning Hardened Steel with Tool<sup>’</sup>s Chamfer Angle and Edge Preparation Considered

The performance and wear mechanisms of one type of polycrystalline cubic boron nitride (PCBN) cutting tool with two different cutting edge micro geometries (marked as PCBN 169T and PCBN 169S) have been investigated in this paper. Interrupted turning of round GCr15 steel has been selected as the test method. The experimental results indicate that PCBN 169S has a greater thermal wear resistance than PCBN 169T at high cutting speeds. It is believed that edge preparation can shorten or eliminate the initiative wearing stage, improve the impact resistance, reduce the occurrence of chipping or dilapidation, and extend tool life. Scanning electron microscopy (SEM) were used to evaluate wear mechanisms of PCBN tools. Our results show that the dominant wear mechanisms for PCBN 169T and PCBN 169S are mechanical and chemical wear.

A Method and Device for 3D Recognition of Cutting Edge Micro Geometry

A Method and Device for 3D Recognition of Cutting Edge Micro Geometry

Influence of cutting edge radius on surface integrity and burr formation in milling titanium

The influence of the cutting edge micro geometry on cutting process and on tool performance is subject to several research projects. Recently, published papers mainly focus on the cutting edge rounding and its influence on tool life and cutting forces. For applications even more important, however, is the influence of the cutting edge radius on the integrity of the machined part. Especially for titanium, which is used in environments requiring high mechanical integrity, the information about the dependency of surface integrity on cutting edge geometry is important. This paper therefore studies the influence of the cutting edge radius on surface integrity in terms of residual stress, micro hardness, surface roughness and optical characterisation of the surface and near surface area in up and down milling of the titanium alloy Ti–6Al–4V. Moreover, the influence of the cutting edge radius on burr formation is analysed. The experiments show that residual stresses increase with the cutting edge radius especially in up milling, whereas the influence in down milling is less pronounced. The influence of the cutting edge radius on surface roughness is non-uniform. The formation of burr increases with increasing cutting edge radius, and is thus in agreement with the residual stress tests.

A new method for the characterisation of rounded cutting edges

The influence of the cutting edge micro geometry on cutting process and on tool performance is subject of several research projects. Recently published papers focus on optimising the cutting edge rounding. The results are partly inconsistent. Unfortunately, no international standard yet exists to properly describe the cutting edge micro geometry. This is seen as the root cause for detected discrepancies. To develop a common understanding for the influence of rounded cutting edges, it is indispensable to use the same basis to characterise the edge profile. This paper gives a review on existing characterisation methods, analyses the difficulties in their application and discusses different modelling ideas to describe the cutting edge profile. Based hereon, a new algorithm and geometrical parameterisation of the cutting edge is proposed, which reduces uncertainties and difficulties in the application of currently available methods. The proposed method considers measurement uncertainties and is robust against form errors and creates thus the basis required for the study of the influence of rounded cutting edges.

Effects of the cutting edge microgeometry on tool wear and its thermo-mechanical load

Tailored cutting edge micro geometries lead to a significant enhancement of the cutting tool performance and increase its tool life. This paper presents the influence of honed cutting edge geometries on the tool wear behavior, process forces and thermal load of the inserts during turning operations. Tool life maps, which show the influence of the honed cutting edge on the wear behavior, are developed for different thermomechanical load profiles of the cutting tool. Furthermore, an approach for space resolved temperature measurements near the cutting edge via two-color ratio pyrometer is presented.

An approach to reduce the influence of tool wear on workpiece properties during hard turning

Tool wear during hard turning of steel materials leads to unfavourable changes of the workpiece subsurface layers. Due to progressive flank wear at the cutting edge, thermal and mechanical loads affect adversely the residual stresses at the workpiece subsurface and white layers occur within the microstructure. These effects lead to a reduction of the functional behaviour of such machined components at operational conditions, especially under dynamic mechanical loads. This paper presents a method to avoid negative influences at machined subsurface layers in terms of residual stress. A modified cutting edge micro geometry is applied to assure a reliable process even with worn cutting tools by limiting the contact conditions between the tool and the workpiece interface at the tool flank face.

Hard turning of interrupted surfaces using CBN tools

Some of the advantages of using turning instead of grinding for the finish machining of hardened steel surfaces are: high flexibility, the ability to cut complex surfaces with a single machine set up, cost of the process, and the possibility of turning without cutting fluid. On the other hand, turning is not very suitable for cutting hardened interrupted surfaces, since most of the tools used in this operation are not very tough. This work aimed to broaden the use of hardened steel turning tools, comparing the use of two CBN tool grades (low CBN content, called 7020, and high CBN content, called 7050) and two cutting edge micro geometries (chamfered and rounded edge) in radial turning of three kinds of surfaces: continuous, semi interrupted and interrupted. The comparison was in terms of tool wear and tool life. The workpiece material was AISI 4340 steel with 56 HR C of hardness. Results showed that the longest tool life was obtained when the 7020 grade was used, regardless of surface type. However, in continuous cutting, tools with chamfered edges proved to have the longest life, while for interrupted cutting the best results were produced by tools with edge rounding.