Workpiece Surface Quality Research Articles

Effects of Cutting Parameters on Tool Wear in Milling Inconel 625 Superalloys with a SiAlON Ceramic and the Prediction of Tool Life

Inconel 625 superalloys are widely preferred in various industries because of their superior mechanical properties at high temperatures. The superior properties they exhibit make the machinability of Inconel 625 alloys difficult. This situation can cause rapid wear of the cutting tools, making the cutting tool unusable in very short periods of time and causing deterioration of the workpiece surface quality. Therefore, improving the machining performance of Inconel 625 alloys, optimizing the machining parameters and using the optimum cutting tool material and geometry are important. In this study, SiAlON ceramic cutting tools, which have been widely used in recent years, were preferred. SiAlON tools supplied in raw rod form were subjected to various processes and finalized into final products. The effects of three different cutting speeds (vc), feed rates (f) and axial depth of cut (ap) on tool life (T), wear patterns and mechanisms were investigated with 9 tests designed according to the Taguchi L9 orthogonal array. The results revealed that the f values, the effects of which were analysed, had the most significant effect on T. By performing regression analysis with T values, the coefficients used in the extended Taylor T equation were determined, and T predictions were obtained. The regression model was found to be consistent with the experimental results, with an effect of 99.34%, and the model was significant according to analysis of variance. The predominant wear patterns of the cutting tools were flaking at a low vc, nose collapse at a high vc and an adhered workpiece under all conditions. The wear mechanism was found to be predominantly adhesion and fracture. The presence of Ni, Cr, Mo, Nb and Fe on the cutting tool surface was determined, and the effect of the concentrations was observed to increase/decrease significantly depending on the parameter values examined.

Research on size optimization of 3D printed parts using Grey-Taguchi method

Abstract Fused deposition modeling (FDM) is one of the earliest developed 3D printing processes, which has the advantages of a clean processing environment, low overall manufacturing costs, and a variety of optional materials. However, it still has the disadvantages of low dimensional accuracy and poor surface quality of the molded workpiece. Therefore, how to solve this annoying problem has become an important research topic in the current industry-university-research fields. In this study, a square container with a bottom area of 48 mm×48 mm, a height of 30 mm, and a thin wall of 6 mm was used as the design object, and four controllable factors were adopted: layer thickness (A), nozzle temperature (B), printing speed (C), and forming path (D), combined with Grey- Taguchi’s experiments and calculations are carried out in order to achieve the purpose of optimizing the inner volume (IV) and inner diagonal length (IDL) of the square container (dual-objective quality characteristics). The experimental results show that within the selected printing parameter range, the optimized process parameter combination is layer thickness of 0.25 mm (A3), nozzle temperature of 190 °C (B1), printing speed of 50 mm/s (C3) and the molding direction of the annular surface (D2). Finally, use the GOM Inspect software (ATOS Q 3D scanner) and vernier caliper (VC) to compare the physical errors. According to the verification results, the errors of IV and IDL of the square container obtained by optimizing process parameters are 0.49% and 1.53%, and 3.76% and 6.33% respectively in GOM Inspect software and vernier caliper measurement. The results of this optimization process not only prove that the GOM Inspect software has a considerable degree of accuracy, but also can be used as a means to improve FDM multi-quality printing process optimization when combined with the Grey-Taguchi method.

Technological support of workpiece surface quality based on local cryogenic impact during processing of austenitic steels

Technological support of workpiece surface quality based on local cryogenic impact during processing of austenitic steels

Influence of different machining methods on the surface roughness of TC4: dry milling, water-based fluid wet milling, and foam spray milling

The surface quality of workpieces is influenced by various factors, including processing parameters, processing techniques, cutting force, and cutting vibration. Many researchers have studied wet cutting to minimize milling forces and vibrations. We explore a high-density water-based foam milling method. By this method the foam is sprayed onto the surface area of tool and workpiece to absorb vibration energy. Firstly, a milling test system was established to conduct tests on TC4 titanium alloy under three different machining conditions (dry milling, water-based fluid wet milling, and foam spray milling), and the three-dimensional (3D) milling forces and milling vibrations were simultaneously recorded during the milling process, and the workpiece’s surface roughness was measured using a contact roughness measuring instrument. Then principal component analysis method was performed on the 3D milling forces and vibrations to obtain dimensionality-reduced feature values. Subsequently, multi-feature combination prediction models of surface roughness corresponding to the three machining conditions were developed using particle swarm optimization and a generalized regression neural network. Finally, the developed prediction models were compared and analyzed. The research results indicate that high-density water-based foam spray milling can effectively reduce the milling force by 70% and the milling vibration by 85% at most. Foam spray milling reduces the average roughness by up to 49%. The roughness prediction accuracy reaches 95.43%, with an error of less than 0.054 µm.

A wireless and passive tool holder for online measurement of milling temperature

Abstract The measurement of cutting temperature is very important in monitoring the manufacturing process and greatly impacts tool wear and the workpiece surface quality. Milling temperature measurement is particularly difficult due to high-speed rotation. This paper uses an intelligent and wireless passive tool-holder system for milling temperature sensing, with a resolution of 0.25°C, a range of 0~700°C, and an update speed of 10 Hz. Thermocouple is pre-embedded in the machined groove near the cutting edge on the flank face of the milling tool, and signal acquisition circuits and wireless transmission module are integrated into the tool holder system for online signal processing. Based on electromagnetic induction, the self-power supply scheme is designed by converting the rotating kinetic energy of the spindle to electricity, and hierarchical energy regulation is achieved to realize a stable and constant power supply. With a temperature-sensing intelligent tool holder, cutting experiments on different processing parameters are carried out to verify the feasibility of the measurement system.

Effect of structure tool on nano-cutting surface integrity of single crystal γ-TiAl alloy via atomic simulation

To investigate the impact of microgroove geometry at the tool's flank face on the surface integrity of the workpiece, molecular dynamics simulation is utilized to establish a model of cutting single crystal γ-TiAl alloy using various structured nanodiamond tools. The effect of groove shape on the surface integrity of single crystal γ-TiAl alloys was investigated by analyzing mechanical properties, workpiece surface quality, and subsurface damage during the cutting process. The results show that non-structured tool cuts γ-TiAl alloy with the highest cutting force, and the V-groove tool cuts with the lowest friction coefficient, which is favorable for the removal of single crystal γ-TiAl alloy. Statistical atomic phase transitions during cutting confirmed that structured tools reduce subsurface damage, especially V-grooved tool reduce the generation of defective atoms. The circular arc grooved tool effectively reduces the subsurface temperature of the single crystal γ-TiAl alloy workpiece by reducing the friction at the tool chip interface due to lower normal cutting force. In addition, the circular arc grooved tool cutting has stronger atomic flow and surface recovery ability compared with other tools, and smaller surface roughness can be obtained. Therefore, selecting a reasonable structured tool can effectively improve the machinability of single crystal γ-TiAl alloy.

An Investigation of the Effect of Novel Mono/Bi-Layered PVD-Coated WC Tools on the Machinability of Ti-5Al-5V-5Mo-3Cr.

The Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy is a relatively novel difficult-to-cut material with limited machinability and tool life analysis available in the literature, and hence requires further investigation. This study focuses on the machining and tribological performance of Ti-5553 under high-speed finish turning (150 m/min, 175 m/min, and 200 m/min) via novel mono/bi-layered PVD-coated WC tools. A base AlTiN coating is used as the reference monolayer coating, with AlCrN, diamond-like ta-C, and TiAlSiN coatings each deposited on top of a base AlTiN coating, totaling four separate coated tools (one monolayer and three bi-layer). Tool life, cutting forces, workpiece surface quality, and tribological chip analysis are among the subjects of investigation in this study. Overall, the AlTiN/AlCrN coated tool outperformed all the other combinations: an improvement of ~19% in terms of tool life in reference to the base AlTiN coating when averaging across the three speeds; lowest surface roughness values: ~0.30, 0.33, and 0.64 µm; as well as the lowest chip back surface roughness values: ~0.80, 0.68, and 0.81 µm at 150, 175, and 200 m/min, respectively. These results indicate that the AlTiN/AlCrN coating is an excellent candidate for industrial applications involving high-speed machining of Ti-5553.

Coupling pulsed magnetic treatment coated WC-12Co cemented carbide and magnetofluid to enhance milling performance of TC4 alloy

To explore an eco-friendly approach to improve the milling performance of TC4 (Ti-6Al-4 V) alloy, pulsed magnetic field treatment and magnetofluid are simultaneously applied to the NbN-coated cemented carbide (WC–12Co) milling tools. To evaluate the coupling effect of pulsed magnetic field treatment with magnetofluid, milling experiments of TC4 were conducted under cutting fluid and magnetofluid lubrication, respectively. The milling force, tool wear, and workpiece surface quality of magnetic field treated tools were compared with those of untreated tools. When the cutting fluid was lubricated, the magnetic field treatment reduced the feed force by 8.8 %. In contrast, the magnetic field treatment reduced the feed force by 20.7 % when the magnetofluid was lubricated, which reduced tool wear and also weakened coating flaking. The coupling of the magnetic field treatment and the magnetofluid significantly improved the milling performance of the tool, reducing surface roughness by 40.9 % compared to the untreated tool with cutting fluid lubrication. The enhanced milling performance mainly results from the coupling effect of magnetic field treatment and magnetofluid, which has a strong magnetic response to the treated tool and the magnetofluid was attracted to the magnetized tool, enhancing the lubrication of the contact area. In addition, the enhanced mechanical properties (8.2 % increase in hardness, 13.1 % decrease in elastic modulus, and 4.5 % increase in thermal conductivity) resulting from the pulsed magnetic field treatment reduces the milling temperature (11.7 °C) also contribute to the enhanced milling performance.

Comprehensive Evaluation Study of Innovative Measurement Techniques in Surface Roughness within Manufacturing Processes

Abstract With the advancement of modern technology, numerous advanced methods for measuring surface roughness have emerged. These are categorized into contact and non-contact methods, such as optical, ultrasonic, and machine vision measurements. By researching and integrating various characteristics, including cutting parameters, vibration, and force signals, with workpiece texture images, a comprehensive model for predicting surface roughness is formed. These novel multidimensional feature prediction equations significantly enhance practicality and accuracy in assessing the surface quality of machined workpieces, marking a clear advancement over traditional measurement techniques.

Experimental Study on the Comparison between Network Microstructure Titanium Matrix Composites and Ti6Al4V on EDM Milling.

Network microstructure titanium matrix composites (NMTMCs), featuring Ti6Al4V as the matrix and network-distributed TiB whiskers (TiBw) as reinforcement, exhibit remarkable potential for diverse applications due to their superior physical properties. Due to the difficulty in machining titanium matrix composites, electrical discharge machining (EDM) stands as one of the preferred machining techniques for NMTMCs. Nevertheless, the compromised surface quality and the recast layer significantly impact the performance of the workpiece machined by EDM. Therefore, for the purpose of enhancing the surface quality and restraining the defects of NMTMCs, this study conducted comparative EDM milling experiments between NMTMCs and Ti6Al4V to analyze the effects of discharge capacitance, charging current, and pulse interval on the surface roughness, recast layer thickness, recast layer uniformity, and surface microcrack density of both materials. The results indicated that machining energy significantly influences workpiece surface quality. Furthermore, comparative experiments exploring the influence of network reinforcement on EDM milling revealed that NMTMCs have a higher melting point, leading to an accumulation phenomenon in low-energy machining where the reinforcement could not be completely removed. The residual reinforcement in the recasting layer had an adsorption effect on molten metal affecting the thermal conductivity and uniformity within the recasting layer. Finally, specific guidelines are put forward for optimizing the material's surface roughness, recast layer thickness, and uniformity, along with minimizing microcrack density, which attain a processing effect that features a roughness of Ra 0.9 μm, an average recast layer thickness of 6 μm with a range of 8 μm, and a surface microcrack density of 0.08 μm-1.

Active vibration control in robotic grinding using six-axis acceleration feedback

Industrial robots endure severe vibrations in the grinding process due to factors such as joint flexibility, low damping, and contact force fluctuations. Additionally, the motion control of the robot primarily relies on feedback signals from the motor-side encoders, while lacking motion state feedback from the load side. This exacerbates the robot vibrations, severely compromising the surface quality of the workpieces. To address this problem, an active damping control method for robotic grinding using six-axis acceleration feedback is proposed. This method realizes a simple, reliable, and efficient active vibration control without altering the robot body. A multi-sensor fusion Cartesian space six-axis accelerometer is designed and integrated into the robot end effector, achieving accurate feedback on the robot load side vibration state. The strategy of six-axis acceleration decoupling and principle of the vibration suppression with the acceleration feedback are explained. Compared with conventional sensing schemes, this reduces joint acceleration approximation errors and end vibrations. The robotic grinding experiments are carried out on aeronautic structural parts. Extensive case studies demonstrate that the proposed approach can effectively control the vibration caused by joint flexibility in the robot grinding process, and greatly improve the surface quality of workpieces. This method has great potential application in vibration suppression during robotic grinding and polishing.

Research on the Grinding Performance of an Electroplated Coarse-Grained Diamond Grinding Wheel by Dressing

The coarse-grained electroplated diamond grinding wheels is increasingly favored in precision grinding of hard and brittle materials owing to its high material removal efficiency, high wear resistance and steady surface contour accuracy. However, how to determine whether the dressed grinding wheel surface topography can achieve the desired precision ground surface quality is still a huge challenge to this day. In this paper, a novel numerical simulation model, which was established basing on the statistical features of actual electroplated coarse-grained diamond grinding wheel and the kinetics of the grinding process, was proposed for theoretically and thoroughly studying the influence of the surface dressing depth of coarse-grained electroplated diamond grinding wheel on ground workpiece surface morphology. At first, the statistical features of actual electroplated coarse-grained diamond grinding wheel was acquired and a novel numerical grinding wheel surface model was established. Subsequently, a numerical ground workpiece surface simulation model was also developed. And then, the evolving mechanism of the grinding wheel surface topography with the dressed wheel surface abrasive grain protrusion height was theoretically studied by numerical simulation. Moreover, the influence of the wheel surface abrasive grain protrusion height on the ground surface roughness was thoroughly researched by means of theoretical model and experiments. The simulation and experiments results in this paper indicated that precision ground workpiece surface with nano-scale surface roughness can be acquired by grinding with a dressed grinding wheel with a certain abrasive grain protrusion height of 25% of the typical abrasive size. Comparing with the undressed grinding wheel (grinding wheel with original surface topography and not be dressed), the surface roughness Sa and Sq of the surface ground with a well-dressed wheel can achieving a significant decrease of 97.75–99.77% and 97.57–99.73%, respectively. Therefore, carefully dressing the electroplated coarse-grained diamond grinding wheel is of great significance for obtaining a precision ground workpiece surface quality.

Effect of Vibration Direction on Vibration-Assisted Fixed Abrasive Polishing

In order to study the effect of vibration direction on vibration-assisted fixed abrasive polishing and explore the influence rule of vibration direction on material removal rate and workpiece surface quality, a single abrasive particle vibration-assisted fixed abrasive polishing model was established to study the effect of axial and radial vibration on workpiece profile depth, surface morphology, etc. And the experiments of vibration-assisted fixed abrasive polishing in different vibration directions were carried out. The results show that axial vibration auxiliary polishing can greatly advance the processing efficiency, and improve the workpiece material removal rate by 27.6%; radial vibration auxiliary polishing can achieve better surface quality, and reduces the surface roughness by 59.8%.

Effect of Electrolyte Filtration Accuracy on Electrochemical Machining Quality for Titanium Alloy

<p>Electrochemical machining (ECM) is an effective manufacturing method for difficult-to-machine materials and is widely used in the precision manufacturing of aerospace components. In recent years, the requirements for the machining accuracy and surface integrity of ECM have become increasingly stringent. To further improve the machining quality, this work investigated the intricate laws between electrolyte filtration accuracy and machining quality. Electrolytes with different filtration accuracies were compared, and a numerical simulation was used to evaluate the change in temperature and bubble rate of the flow field in the machining area. Experiments were conducted on ECM of Ti-6Al-4V (TC4) alloy workpieces using electrolytes with different filtration accuracy. The workpiece machining accuracy and surface quality were analyzed, and the repetition accuracy of the workpiece was evaluated. The intricate laws between electrolyte filtration accuracy and machining quality were explored. It was found that when the electrolyte filtration accuracy is improved, so too is the machining quality of the ECM. However, once the filtration accuracy has reached a certain value, the machining quality has extremely limited improvement. By evaluating the repetition accuracy of processed workpieces in electrolytes with different filtration accuracies, it was found that when the filtration accuracy reaches a certain value, there is no positive correlation between the repetition accuracy and filtration accuracy. The result shows that, for the workpiece material and conditions considered in this paper, an electrolyte with 0.5μm filtration accuracy is suitable for the wide application of precision ECM.</p>

Research on tool wear and surface quality in laser-assisted ultrasonic elliptical vibration cutting of cemented carbide

The Laser-ultrasonic elliptical vibration cutting (LA-UEVC) method was introduced for machining challenging cemented carbide. The machining parameters were estimated through numerical simulation, and the cutting forces, the tool wear and the workpiece surface quality were analyzed and investigated. Compared to precision cutting, during LA-UEVC of cemented carbide, the main cutting force and the cutting radial thrust force were reduced by 44.3% and 31.2%, respectively. Moreover, the tool wear decreased, which led to an increase in tool life by 118.8%, and a maximum reduction of 89.7% of Workpiece surface roughness was received. The impact of laser power and cutting parameters on surface roughness was analyzed through orthogonal experiments, and a surface roughness prediction model was established using a quadratic regression model.

Tool life assessment of high strength cast iron alloys in dry face milling operations

The advancement in cast iron alloy properties has led to more efficient materials, especially in the automotive industry. However, this progress has also increased the demand for more durable tools with greater resistance to cutting operations. Conducting an in-depth investigation into the impact of these materials on tool lifespan is crucial, as it directly affects productivity. The main objective of this study was to analyze the lifespan of uncoated cemented carbide tools during milling operations using four high-strength cast iron alloys under various dry cutting conditions. A full factorial Design of Experiment (DoE) (23) was employed. The input variables included cutting speed (vc) of 230 and 350 m/min, tool feed (fz) of 0.1 and 0.2 mm/tooth, and materials, namely cast irons (FC 250, FC 300(Mo), FC300(Mo+RG), and FV 450). Additionally, material tests were conducted on billets without holes to simulate mild cutting conditions and with holes for more severe machining conditions. The established machining operation was face milling without cutting fluid, with the axial depth of cut (ap) and radial depth of cut (ae) maintained constant at 1 mm and 60 mm, respectively. The results showed that FV 450 had the shortest tool life, as expected for the hardest and resistant material, with a maximum lifetime difference of 83 % less when compared to FC 250, the softest one that had the longest tool lifespan. The introduction of holes also significantly reduced the overall tool life by about 57 %. The findings highlight the importance of factors such as cutting speed, feed per tooth, material composition, impact, and workpiece surface quality, which significantly influence tool performance.

Novel Framework for Quality Control in Vibration Monitoring of CNC Machining.

Vibrations are a common issue in the machining and metal-cutting sector, in which the spindle vibration is primarily responsible for the poor surface quality of workpieces. The consequences range from the need to manually finish the metal surfaces, resulting in time-consuming and costly operations, to high scrap rates, with the corresponding waste of time and resources. The main problem of conventional solutions is that they address the suppression of machine vibrations separately from the quality control process. In this novel proposed framework, we combine advanced vibration-monitoring methods with the AI-driven prediction of the quality indicators to address this problem, increasing the quality, productivity, and efficiency of the process. The evaluation shows that the number of rejected parts, time devoted to reworking and manual finishing, and costs are reduced considerably. The framework adopts a generalized methodology to tackle the condition monitoring and quality control processes. This allows for a broader adaptation of the solutions in different CNC machines with unique setups and configurations, a challenge that other data-driven approaches in the literature have found difficult to overcome.

Self-lubricating performance of a grinding wheel filled with CNTs@T304 nano-capsules

This paper introduces a new grinding wheel which lubricates the grinding area directly. This is achieved by filling a resin grinding wheel with nano-capsules comprised of carbon nanotubes (CNTs) and di-n-butyl phosphite (T304) (CNTs@T304). The CNTs@T304 nano-capsules filled grinding wheel reduces the grinding force, lowers the grinding temperature, and improves the workpiece surface quality. The T304 lubricant is first filled into the CNT cavity to prepare nano-capsules, which exhibit better friction and wear quality than CNTs. Then the paper analyzes the configuration of the nano-capsules in the grinding wheel, together with the investigation of how the filling content impacts the mechanical properties. Additionally, the effects of nano-capsule filling content and grinding parameters on grinding force, grinding temperature, grinding ratio, as well as workpiece surface roughness are studied and the self-lubricating mechanism of the nano-capsules is assessed. According to the experimental results, nano-capsules maintain stable under thermal condition and resist the curing temperature. Moreover, the tensile strength and hardness exhibited by the grinding wheel still meet the application requirements at a filling content <16 wt%. Compared with the grinding wheel without fillers, the nano-capsule filled wheel exhibits superior grinding performance, with a 33 % reduction in the grinding force. Also, the grinding temperature is 28 % lower, there is a 30 % improvement in the grinding ratio, and the workpiece surface quality increases by 35 % under the same conditions. The T304 in the nano-capsules is continually released onto the grinding interface with the wear of the wheel in the grinding process, which forms a self-lubricating layer along with the friction products of the CNTs. This exerts an outstanding anti-friction and anti-wear effect, thereby improving the grinding performance.

Exploring workpiece surface quality formation with abrasive dynamics in centrifugal-rotary processes

This article presents the results of research on centrifugal-rotary processing in an abrasive medium. The dynamic characteristics and rotational processes of an array of abrasive granules in the machine chamber are investigated with the aim of determining the motion velocity, contact pressure and energy of the particle flow. These research data will be used in modeling a single interaction of abrasive granules with the surface of a workpiece and obtaining quantitative estimates of material removal rates and parameters on surface roughness of the workpiece and obtain a valuation of material removal rates and workpiece surface roughness parameters. The deformation of granular mass under the action of centrifugal force was performed using the finite element model in the Comsol Multiphysics package. The velocity fields and pressure in the mass of the load are identified. The dependency is obtained to calculate the maximum penetration depth of abrasive particles into the workpiece surface, metal removal and surface roughness. The dependencies are obtained to calculate the maximum penetration depth of abrasive particle into the workpiece surface, metal removal and surface roughness. CAD TP block has been developed to optimize the centrifugal-rotary machining, allowing a significant expansion of the range of computer-aided design systems.

Tool wear and its mechanism in turning aluminum alloys with image processing and machine learning methods

Tool wear is intimately related to intelligent operation and maintenance of automated production, workpiece surface quality, dimension accuracy, and tool life. Therefore, it is necessary to improve the production efficiency and quality by predicting tool wear values. The purpose of this research is to use machine learning and image processing methods in estimating the tool wear values when turning AA7075 aluminum alloy. In addition, the in-depth analysis of cutting tools at different parameters were examined with SEM and EDS analysis. The results shown that there was a 44.40% increase in tool wear when the cutting speed was raised by 100% while feed rates were maintained at the same level. On the other hand, there was a 22.78% increase in tool wear seen when the cutting speed was maintained at the same level. In addition, the difference between the actual values and the image processing model is 3.5%, and the difference between the Multilayer Perception (MLP) model and the linear regression (LR) model is 5% and 7%, respectively.