Drag Finishing Research Articles

Evaluation of Suitability of High-Speed Drag Finishing Machine Prototype Utilization for Workpiece Modification

The purpose of the experimental results evaluated in this paper is to verify the viability of using a prototype drag finishing machine for the modification of machined workpieces. The workpieces used in the experiments had a cylindrical shape and were manufactured by turning. Three different workpiece materials were tested, and three workpieces for each material were machined with different cutting parameters. Multiple aspects of the drag-finishing process influence were kept track of—surface roughness, dimensional accuracy, and edge burr shape change. The parameters of the drag finishing were kept constant for all workpieces, and the development of each aforementioned observed aspect was recorded. The workpieces were periodically removed from the process and measured using a coordinate measuring machine with a touch probe, a surface roughness measuring machine, and an optical microscope. Based on the gathered data, it can be concluded that the usage of a prototype drag finishing machine designed primarily for cemented carbide tool microgeometry modification is viable for workpiece finishing as well. The parameters of the drag-finishing process need to be adjusted depending on the workpiece material and initial surface roughness. Additionally, the medium used for the drag finishing should be considered with respect to the desired output quality of the workpiece. Experimental work shows that having one multi-purpose machine for precise modification of wide range of materials and shapes can be an effective approach from the standpoint of economy and productivity when it comes to small numbers of workpieces requiring surface finishing.

Research on Cutting Edge form Factor of Milling Tool after Drag Finishing Preparation Based on Discrete Element Method

Cutting edge preparation is a precision machining process that improves the surface quality of cutting tools through the relative movement of abrasives and the tool. Research on removing materials in drag finishing can be greatly beneficial to tool manufacturing. This paper proposes the hypothesis that both abrasive wear and erosion wear act on the surface of milling tools and discusses the material removal models for abrasive wear and erosion wear. The influence of immersion depth, abrasive velocity, abrasive radius, and abrasive density on the material removal rate in two material removal forms is compared and validated by discrete element simulations. The results show that immersion depth has a greater impact on abrasive wear, while abrasive properties have a greater impact on erosion wear. The correlation between simulation results and theoretical models demonstrates the sensitivity of the two forms of wear on this surface to parameter change differences. Dragging finishing was conducted to verify the effectiveness of the simulation, and the effects of immersion depth, dragging velocity, and abrasive properties on the edge radius and form factor (K value) were studied.

Influence of selected parameters of drag finishing on tool microgeometry

The aim of the experiment described in the paper was to determine how selected parameters of drag finishing such as process time, immersion depth and rotation frequency affect microgeometry of cutting edge. Four flute cemented carbide mills with diameter of 10 mm were used in this experiment. These mills were drag finished on prototype drag finishing machine developed on Faculty of Materials Science and Technology, Slovak University of Technology. Alicona Infinte Focus SL measuring machine was used to measure microgeometry of these mills. The main parameter of microgeometry of cutting edge was the size of the radius of cutting edge. In the article we compared which parameter has the biggest influence on size of cutting edge radius and also there was statistical evaluation carried out. The most significant parameter of drag finishing was determined to be the immersion depth.

Surface characteristic of Ti-6Al-4V alloy fabricated by Electron Beam Melting prepared by different surface post treatments

Metal additive manufacturing (AM) is a technique in constant growth that offers freedom in design in the production of complex shape components. However, it is well documented that most types of material failures in the AM parts are very sensitive to their surface properties. Hence, in this work, some surface post-treatments such as grinding, drag finishing and Surface Mechanical Treatment (SMT) are used as post-treatment processes to improve the performance of Ti-6Al-4V samples fabricated by the Electron Beam Melting technique. The influences of different post-treatment were investigated on the surface properties. The outcomes demonstrated that the SMT has- the highest efficiency in the surface treatment and could reduce surface roughness, increase hardness and improve wettability. This work demonstrates the potential of SMT to achieve favourable surface properties of AM metallic components.

INCREASING TOOL LIFE THROUGH ADJUSTMENT OF CUTTING EDGE AND TOOLPATH DURING MILLING OF INCONEL 718

This paper focuses on analysis of tool life during milling of nickel alloy Inconel 718. Several modifications of one type of carbide tool with different cutting edge finish adjustments (lapping, drag finishing) were proposed for milling of Inconel 718. These finish adjustments significantly influence cutting edge properties (hardness, radius value, etc.). The toolpath geometry setup has a great influence on chip formation and tool load characteristics during milling strategies. The milling tests were performed by using the cutting tools with several adjustments of cutting edge in combination with the toolpath geometry setup. The paper therefore presents the analysis that tool life can be significantly increased through proper finish adjustment of cutting edge microgeometry and proper toolpath setup.

Effect of cutting edge radius on end milling Ti–6Al–4V under minimum quantity cooling lubrication – Chip morphology and surface integrity study

The effect of cutting edge radius (30–55 μm) during milling Ti–6Al–4V under minimum quantity cooling lubrication (MQCL) conditions is studied. A trial study is conducted to compare the performance of dry, wet, and MQCL using unprepared tools with edge radius of 30 μm alone. Subsequently, inserts having initial radius of 30 μm are prepared to 40–55 μm radius using drag finishing and milling of Ti–6Al–4V under MQCL is studied for different edge radii. Rounded edge tools are found to produce thinner and more curvilinear chips resulting in easier chip removal from the machining zone. The chip thickness and curl radius were up to 54% and 47% lower for the larger edge radius tools as compared to the 30 μm edge radius tool. This improves the penetration of the MQCL aerosol jet into the cutting zone thus producing better tribological results. The better penetration of MQCL aerosol into the cutting zone for larger edge radius tools results in lowering the resultant process forces (up to 16%), tool-chip interface temperature (15%), tool wear (40%) and surface roughness (30%) for the 48 μm radius tool as compared to the unprepared (30 μm) tool. There is deterioration in process forces, tool wear and surface integrity for the 55 μm tool possibly suggesting the existence of an optimum edge radius closer to 48 μm.

Machining Evaluation of Carbide Drill and Cermet Reamer Using Polishing Media Based on Drag Finishing Process

Machining Evaluation of Carbide Drill and Cermet Reamer Using Polishing Media Based on Drag Finishing Process

Analysis of abrasives on cutting edge preparation by drag finishing

Cutting edge preparation has become more important for tool performance. The micro-shape, radius and surface topography of the cutting edge play a significant role in the machining process. The cutting edge of solid carbide end mills has some micro-defects after grinding. For eliminating aforementioned problem, this study investigates drag finishing (DF) preparation for solid carbide end mills to reconstruct cutting edge micro-geometry. This paper is to present the design of DF experimental setup and analyze the characterization of various abrasive media (K3/600, K3/400, HSC 1/300 and HSO 1/100) on the evolution of the surface/roughness along the cutting edge. In parallel, the mechanism of material removal and the kinematics trajectory of the drag finishing are presented. In fact, the form factor (also called as “K-factor”) of the cutting edge micro-geometry is quantified. Comparing with four lapping media, the higher material removal rate (MRR) and the lower surface roughness are obtained by HSO 1/100 abrasive process. The results show that the cutting edge K-factor, MRR and surface topography are influenced by the abrasive particles size, composition and process time.

Effect of machining and drag finishing on the surface integrity and mechanical properties of Inconel 718 alloys fabricated by laser powder bed fusion additive manufacturing

AbstractLaser powder bed fusion process is one of the most widely used Additive Manufacturing techniques for fabricating metal components, however the surface quality of such components still remains a challenge and fails to meet the user expectations. Thus, this study presents a systematic investigation on the effect of post‐processing operations including finish milling and drag finishing on the surface integrity and resulting mechanical properties of Inconel 718 specimens fabricated by laser powder bed fusion additive manufacturing technique. The influence of post‐processing operations on the surface and subsurface microstructure, microhardness and tensile strength on the Inconel 718 specimens are carefully examined and presented in this study. Finally, this work also contributes to understanding the critical wall (part) thickness that is notably induced from the post‐processing operations. It is revealed that the surface integrity and resulting mechanical properties of specimens significantly improved as compared to as‐built specimens once milling and drag finishing post‐processing are deployed. However, the degree of impact depends on the thickness of parts subjected to post‐processing.

Numerical modelling of the drag finishing process at a macroscopic scale to optimize surface roughness improvement on additively manufactured (SLM) Inconel 718 parts

Drag finishing is one of the mass finishing processes that enhances surface roughness on complex and rough parts produced by additive manufacturing. This paper proposes a model to simulate abrasive media flowing around the part at a macroscopic scale based on an original rheological model inspired by civil engineering techniques. The correlation between the evolution of the surface roughness and numerical results reveals the high sensitivity of the process to media’s rheological behaviour and the surface orientation of the surface regarding media flow. This model provides a better understanding of the physical mechanisms (chip formation or plastic deformation) induced at the surface during polishing, and it helps choosing the optimal finishing conditions.

A new hybrid electrochemical-mechanical process (PEMEC) for polishing complex and rough parts

A new polishing process for metallic parts has been developed by simultaneously coupling drag finishing and electrochemical polishing. This new hybrid process, called PEMEC, enables an improvement in the surface roughness within some minutes, and at the same time, preserves the shape of the edges. This hybrid process is based on a synergistic effect between abrasive and chemical mechanisms. It has confirmed its suitability to be applied on complex and rough surfaces produced by additive manufacturing SLM parts.

Investigation of vibratory bed effect on abrasive drag finishing: a DEM study

Purpose The purpose of this paper is to investigate the effect of a vibratory bed, as an assistant agent, on the improvement of the drag finishing process. The dynamics and kinematic of the process were surveyed in microscale for different frequencies and amplitudes and the results were compared to the basic process. Design/methodology/approach The discrete element tool was used to find out the effect of the vibratory bed on the drag finishing process. To this end, the Hertz-Mindlin model was used to investigate the contact of abrasive particles and workpiece. At the first stage, the numerical model was validated with the experimental results, and then the effect of different parameters on the finishing process was evaluated and compared with the basic case. Findings The chosen numerical model was in good agreement with the results measured in the previous literature. Moreover, the results show that not only vibrated bed enhances the contacts of abrasive particles to the workpiece, but it also increases the uniformity of the finished surface. Originality/value In comparison to the experiments, the discrete element technique consumes lower cost and time to estimate the optimum conditions of the finishing process, as well as it provides a good understanding of this phenomenon on the micro-scale.

Numerical and experimental analysis of thermal and mechanical tool load when turning AISI 52100 with ground cutting edge microgeometries

Tools made of polycrystalline cubic boron nitride (PcBN) are usually prepared with a rake face chamfer to increase the performance in hard turning. This chamfer is produced by a tool grinding process. The preparation of the cutting edge itself considering the process and material properties offers further potential for increasing tool performance. In this paper, the rounding of the cutting edge is produced by the already established and highly productive tool grinding process instead of using conventionally processes such as brushing or drag finishing. Therefore, the rounding is approximated by multiple ground chamfers. The influence of the cutting edge microgeometry on the thermomechanical load is investigated by finite element method. By enlarging the microgeometry, the mechanical stress on the tool is significantly reduced. However, an increase in the size of the cutting edge rounding is also linked to an increase in the thermal tool load.

COMPARISON OF PREPARATION METHODS IN TERMS OF TOOL LIFE AND SURFACE ROUGHNESS

The article compares two cutting edge preparation methods and their influence on the machined surface roughness of the difficult to cut nickel alloy Inconel 718 and the tool wear of cutting inserts made of cemented carbide. The manufacturing and preparation process of cutting inserts used in the experiment were made by Dormer Pramet. The preparation methods used in the experiment were drag finishing and brushing. Cutting parameters did not change during the whole turning process to maintain the same conditions in each step of the process and were determined based on tests for a semi-finishing operation of the turning process. To obtain durability of 25 to 30 minutes with controlled development of the tool wear the cutting parameters were determined with cooperation with the cutting inserts manufacturer.

Identification of interaction mechanisms during drag finishing by means of an original macroscopic numerical model

Drag finishing is one of the mass finishing processes that enhances surface roughness on complex parts due to the mechanical action of abrasive media. Due to the complexity of the process, industrial practice is based on experience. This paper proposes a model simulating abrasive media flowing around a part during a drag finishing operation at a macroscopic scale. The 2D model is based on an Arbitrary Lagrangian Eulerian (ALE) formulation that provides relevant mechanical parameters such as the distribution of stresses (normal and shear stresses) and sliding velocities between abrasive media and the surface to be polished. Abrasive media are modelled as a continuous material with a Drucker-Prager plastic constitutive equation. This last has been calibrated as a result of triaxial testing, commonly used to characterise soils in civil engineering. Two abrasive media (spherical and pyramidal shape) having the same composition were characterised. Pyramidal media exhibit significantly higher rheological behaviour compared to spherical one. The model is shown to be very sensitive to the media's rheological behaviour but also to the immersion depth. Pyramidal media leads to much higher normal and shear stresses, which are even higher at deeper immersion depths. Drag finishing experimental tests were carried out to evaluate the efficiency of the model. The correlation between experimental drag finishing tests and numerical test results reveals the physical mechanisms at the interface between media and the surface. Spherical media, with a small/orthogonal orientation impact angle, promotes plastic deformation, while the main mechanisms becomes cutting at higher impact angles. However, pyramidal media promotes cutting irrespective of the orientation angle. Moreover, it was concluded that the optimal mechanical loading combination happens between 30 and 60° for both medias, as the shearing energy reaches its maximum value.

Modeling of Drag Finishing—Influence of Abrasive Media Shape

Drag finishing is a widely used superfinishing technique in the industry to polish parts under the action of abrasive media combined with an active surrounding liquid. However, the understanding of this process is not complete. It is known that pyramidal abrasive media are more prone to rapidly improving the surface roughness compared to spherical ones. Thus, this paper aims to model how the shape of abrasive media (spherical vs. pyramidal) influences the material removal mechanisms at the interface. An Arbitrary Lagrangian–Eulerian model of drag finishing is proposed with the purpose of estimating the mechanical loadings (normal stress, shear stress) induced by both abrasive media at the interface. The rheological behavior of both abrasive slurries (media and liquid) has been characterized by means of a Casagrande direct shear test. In parallel, experimental drag finishing tests were carried out with both media to quantify the drag forces. The correlation between the numerical and experimental drag forces highlights that the abrasive media with a pyramidal shape exhibits a higher shear resistance, and this is responsible for inducing higher mechanical loadings on the surfaces and, through this, for a faster decrease of the surface roughness.

Influence of tool edge form factor and cutting parameters on milling performance

Tool edge preparation can improve the tool life, as well as cutting performance and machined surface quality, meeting the requirements of high-speed and high-efficiency cutting. In general, prepared tool edges could be divided into symmetric or asymmetric edges. In the present study, the cemented carbide tools were initially edge prepared through drag finishing. The simulation model of the carbide cemented tool milling steel was established through Deform software. Effects of edge form factor, spindle speed, feed per tooth, axial, and radial cutting depth on the cutting force, the tool wear, the cutting temperature, and the surface quality were investigated through the orthogonal cutting simulation. The simulated cutting force results were compared to the results obtained from the orthogonal milling experiment through the dynamometer Kistler, which verified the simulation model correctness. The obtained results provided a basis for edge preparation effect along with high-speed and high effective cutting machining comprehension.

Measurement and Modeling of Contact Forces during Robot-guided Drag Finishing

Robot-guided drag finishing is a free abrasive grinding operation that is used for polishing and deburring of workpieces with complex shaped geometries. The workpiece is attached to a robot and moved through a bulk of abrasive particles. The motion of abrasive particles during contact with the workpiece is the basis of the material removal mechanisms. To investigate the motion of abrasive particles during contact, a force measurement system was used to determine contact forces. The experimental setup was replicated in a numerical simulation based on the discrete element method (DEM). Based on the comparison of experimental and simulative results the qualitative validity of the DEM model was concluded. With the presented DEM model, the characteristic particle behavior during contact with the workpiece can be modeled which allows the prediction of resulting processing marks. Consequently, the DEM model can be used to design free abrasive grinding operations without using the time and cost intensive trial and error approach.

The impact of aging and drag‐finishing on the surface integrity and corrosion behavior of the selective laser melted maraging steel samples

AbstractThe maraging steel components fabricated using the selective laser melting process exhibit remarkable static strength. However, high pore density and large surface imperfections impede their overall mechanical and chemical performance. Thus, the components are often post‐treated with mechanical‐ and thermal‐based treatments to overcome their inherent imperfections and enhance their final mechanical properties. Although the post‐processing treatments are useful in enhancing the selective laser melted components’ mechanical performance, their effect on corrosion behavior is not comprehensively evaluated. In this study, the selective laser melting prepared maraging steel samples’ corrosion behavior was examined in the as‐built condition and compared with the post‐processed samples subjected to aging and drag finishing operations. Compared to the as‐built condition, both aging and drag‐finishing post‐processing treatments increased the selective laser melting samples’ corrosion even though the surface integrity was improved.

Effects of cutting edge radius on cutting force, tool wear, and life in milling of SUS-316L steel

Cutting edge micro-geometry plays an important role in machining operations. An appropriate shape and size of the cutting edges improve wear resistance, tool life, and process reliability. This study presents an experimental exploration to understand the rounded cutting edge of solid carbide end mills with CrTiAlN coating on milling SUS-316L steel, and the tool performance in terms of cutting force, tool wear, and tool life is investigated. The designed cutting edge radius (CER) from 4 up to 15 μm is prepared by drag finishing (DF). The results have indicated that the CER are remarkably significant on the cutting performances. With the CER increased from 4 to 15 μm, the cutting force Fc and feed force Ff increased 23% and 56% at uncut chip thickness h = 0.2 mm, respectively. The wear test results showed that chipping is the primary failure of milling cutter. The tool wear mechanism was depicted through scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS) analysis. In conclusion, the highest tool life was obtained with nominal CER of 12 μm in milling of SUS-316L steel.