Surface Quality Characteristics Research Articles

Optimization model of overlap rate of laser cladding based on Gaussian function and top tangent model

As an important characterization of surface quality, the surface morphology of laser cladding coating directly affects the choice and difficulty of subsequent processing technology. The laser cladding coating is made of multi-track cladding layers, and the variation and optimization of overlap rate directly affect the quality of surface morphology. Firstly, the height, width and wetting angle of single-track cladding layer are substituted into the Gaussian function to obtain the characterization curve of single-track cladding layer, which can accurately characterize the profile curve of the single-track cladding layer. Then, by analyzing dual-track overlapping experiments with the variation overlap rates, it was found that the contour of the filled area is approximately a quadratic function curve. The area ratio of the filled area to the overlapping area first decreases and then increases with the increase of the overlap rate, reaching about 0.5 near the optimal overlap rate. Finally, a top-tangent overlapping model is developed based on the single-track characterization model of the Gaussian function and the forming characteristics of multi-track cladding layers. Experimental results show that the model can well characterize the multi-track cladding layers, and it is of great significance for optimizing the overlap rate of laser cladding and obtaining high-quality cladding layers.

Changes in Physical and Water Sorption Characteristics of Three Solid Woods after One-Sided Surface Charring.

One-sided surface charring of wood is a modification process used to lower moisture absorption and improve the resistance to biological degradation for durable surface exterior claddings. Cupressus lusitanica, Gmelina arborea, and Tectona grandis wood samples from fast-growth plantation were charred with a hot plate using three temperatures (300, 350, and 400 °C ± 3 °C) for 10 min. Wood density, surface quality (color and presence of splits), and sorption characteristics (wetting rate and water uptake) were evaluated. Results show that samples charred at 300 °C presented a lower loss of density and thickness than samples charred at 400 °C. Changes in the chemical structure of the wood as a result of the high temperatures caused a decrease of all color parameters (L*, a*, and b*). These values decreased in the samples charred at 400 °C for the three species. Also, the presence of cracks and splits on the surface, or in some cases the presence of detachments from the charring surface, was mostly observed in the samples charred at 350 and 400 °C. One-sided surface charring reduced the liquid water sorption of wood samples in comparison with that of reference samples, especially for C. lusitanica and T. grandis. G. arborea, due to the composition of its anatomical structure and its initial density, chars faster than the other species, causing a greater loss of density, wetting rate values like those of the reference wood, and higher values of water uptake.

Research on the mechanism of microbial corrosion in the subsurface layer of 7075 aluminum alloy under different corrosion environments with ultra low temperature double increase effect

Aluminum alloys exhibit a dual-enhancement effect, characterized by simultaneous increases in strength and ductility at ultra-low temperatures. This study investigates the effects of deep cooling time and corrosion time on the surface quality, elemental distribution, corrosion product films, and electrochemical properties of 7075 aluminum alloy using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical testing. The research reveals that 7075 aluminum alloy surfaces are primarily covered with blocky corrosion products after microbiologically induced corrosion (MIC) in polar marine (PM) conditions, composed mainly of Al(OH)3, Al2O3, and AlCl3. In contrast, in boreal marine (BM) conditions, the surfaces mainly feature cluster-like corrosion products composed of Al(OH)3 and Al2O3. PM exhibits a lower self-corrosion potential compared to BM, and after 5 days of MIC, the self-corrosion potential of 7075 aluminum alloy in PM shifts positively by 0.612 V compared to BM. The BM-9 sample shows the lowest self-corrosion current density at 3.777 × 10^-7 A/cm2, reduced by 81.3 % compared to PM-9, with the BM-9 sample exhibiting the highest polarization resistance at 9.15 × 10^3 Ω cm2. In comparison to the PM MIC environment, BM MIC conditions result in better surface quality and electrochemical characteristics for 7075 aluminum alloy.

On-Machine LTS Integration for Layer-Wise Surface Quality Characterization in MEX/P.

Material Extrusion (MEX) currently stands as the most widespread Additive Manufacturing (AM) process, but part quality deficiencies remain a barrier to its generalized industrial adoption. Quality control in MEX is a complex task as extrusion performance impacts the consistency of mechanical properties and the surface finish, dimensional accuracy, and geometric precision of manufactured parts. Recognizing the need for early-stage process monitoring, this study explores the potential of integrating Laser Triangulation Sensors (LTS) into MEX/P manufacturing equipment for layer-wise 3D inspections. Using a double-bridge architecture, an LTS-based sub-micrometric inspection system operates independently from the manufacturing process, enabling comprehensive digitization and autonomous reconstruction of the target layer's topography. Surface texture is then computed using standardized indicators and a new approach that provides insight into layer quality uniformity. A case study evaluating two alternative extruder head designs demonstrates the efficacy of this integrated approach for layer quality characterization. Implementing a generalized layer-wise procedure based on this integration can significantly mitigate quality issues in MEX manufacturing and optimize process parameter configurations for enhanced performance.

Assessment of Surface Quality during EDM of AISI 4147 with Copper Tool

This experimental assessment is performed to estimate the impact of EDM parameters on surface quality while machining AISI 4147 with a copper tool. The need of the present-day is to achieve good surface quality. Here, an investigation was performed to depict surface quality characteristics with respect to machine variables. The machined specimens were examined under white light interferometry (WLI) for the crests and troughs developed post-machining. The range of average surface finish was found to be between 5.32 to 7.67 µm. The test of model highlighted that the relation linking the EDM variables and surface roughness could be modelled using quadratic equations. As per the SMSS and lack of fit tests, a quadratic model is suggested for the roughness trend obtained. The analysis apprised that duration (p-value = 0.0006) major influence on the surface quality produced while the depth of machining (p-value = 0.9251). At all levels of on time, the surface roughness initially increases and then tends to decrease on increasing peak current. At all current levels, the surface roughness is almost constant with the machining depth; as suggested by ANOVA, it is the least influencing factor. At all levels of duration, the surface roughness is almost constant with depth of machining, and as suggested by ANOVA, it is the least influential factor. Model surface plots are curved representing the presence of quadratic terms in the model. Model validation for surface finish showed that the residual error was lower than 1.48%, proving the adequacy of the model.

Improving the Surface Quality and Tribological Characteristics of 3D-Printed Titanium Parts through Reactive Electro-Spark Deposition.

This work presents the results of research conducted with an aim to improve the surface quality, hardness and wear resistance of titanium alloy Ti6Al4V, obtained via the laser powder bed fusion of metals (PBF-LB/M) process of additive manufacturing (AM) known as the 3D printing of metals. The 3D surfaces were coated via reactive electrospark deposition (RESD) with low-pulse energy and electrode materials of low-melting metals and multi-component hard alloys. The relationship between the electrical parameters of the RESD process and the quality, composition, structure, microhardness and wear resistance of the treated surfaces were investigated and analysed. It was found that the roughness and thickness of the resulting surface layers could be changed by changing the RESD modes within the limits of 2.5-5 µm and 8-20 µm, respectively. RESD processing allowed us to achieve two to five times lower roughness than that of titanium AM surfaces. The microhardness and wear resistance of the RESD surfaces are two to four times higher than those of the titanium substrate. Possibilities for the purposeful synthesis of new wear-resistant phases and compounds and for obtaining surface layers with predetermined thickness and roughness were established. It was shown that the subsequent reaction's electrospark processing helped to simultaneously reduce the roughness and increase the hardness and wear resistance of the modified surfaces, and can be successfully used instead of the material-energy-labour and machine-intensive finishing treatments of the titanium surfaces obtained after 3D printing.

Ductile–brittle transition and ductile-regime removal mechanisms in micro- and nanoscale machining of ZnS crystals

The ductile–brittle transition and ductile-regime removal mechanisms of ZnS crystal, a typical soft-brittle infrared optical material, have remained unclear at the micro- and nanoscale. In this context, this study modeled the energies consumed in two machining modes, namely ductile deformation and brittle fracture, during the ultraprecision cutting of ZnS crystal. Subsequently, based on the transition point of the energy mode, the critical undeformed chip thickness (CUCT) for the ductile–brittle transition of the material was determined. Additionally, the effect of tool parameters on CUCT was quantitatively analyzed, and the correctness of the model was verified by scratch experiments. Moreover, the cutting parameters that affect the maximum undeformed chip thickness (MUCT) were analyzed. By comparing the MUCT and CUCT, the cutting conditions to realize ductile-regime machining were predicted. The correctness of the ductile-regime machining conditions was also verified through surface quality characterization after face-cutting experiments. The MUCT can be controlled to be less than the CUCT by using a cutting tool with a sufficiently large tool rake angle, a nose radius and a reduced feed rate, thus realizing the ductile-regime removal of the material. The surface morphology, chip morphology, and surface roughness of machined ZnS crystal confirmed the validity of the model. Using a diamond cutting tool with a large cutting edge angle (–25°) and nose radius (1.2 mm) as well as a low feed rate (0.5 μm/rev) and depth of cut (3 μm), the generation of cracks and pits was effectively inhibited, resulting in a smooth surface with a surface roughness of 1.60 nm. Overall, the findings of this study provide important insights into the superfinishing of soft–brittle materials such as ZnS crystal.

Fabrication of Electron Beam Melted Titanium Aluminide: The Effects of Machining Parameters and Heat Treatment on Surface Roughness and Hardness

Titanium aluminide alloys have gained attention for their lightweight and high-performance properties, particularly in aerospace and automotive applications. Traditional manufacturing methods such as casting and forging have limitations on part size and complexity, but additive manufacturing (AM), specifically electron beam melting (EBM), has overcome these challenges. However, the surface quality of AM parts is not ideal for sensitive applications, so post-processing techniques such as machining are used to improve it. The combination of AM and machining is seen as a promising solution. However, research on optimizing machining parameters and their impact on surface quality characteristics is lacking. Limited studies exist on additively manufactured TiAl alloys, necessitating further investigation into surface roughness during EBM TiAl machining and its relationship to cutting speed. As-built and heat-treated TiAl samples undergo machining at different feed rates and surface speeds. Profilometer analysis reveals worsened surface roughness in both heat-treated and non-heat-treated specimens at certain machining conditions, with higher speeds exacerbating edge cracks and material pull-outs. The hardness of the machined surfaces remains consistent within the range of 32–33.1 HRC at condition 3C (45 SFM and 0.1 mm/tooth). As-built hardness remains unchanged with increasing spindle and cutting head speeds. Conversely, heat-treated condition 3C surfaces demonstrate greater hardness than condition 1A (15 SFM, and 0.04 mm/tooth), indicating increased hardness with varying feed and surface speeds. This suggests crack formation in the as-built condition is considered to be influenced by factors beyond hardness, such as deformation-related grain refinement/strain hardening, while hardness and the existence of the α2 phase play a more significant role in heat-treated surfaces.

How to improve surface integrity in discrete laser spot hardening of AISI 4140 when using a fiber laser with the Gaussian beam: A dynamic multi-pass approach based on time-domain energy modulation

Improving the surface quality of discrete laser spot hardening when using a fiber laser with the Gaussian beam has been a major concern in industry applications. A dynamic multi-pass approach based on time-domain energy modulation was proposed and successfully implemented using an innovative motion system. Surface quality characteristics, including geometrical dimensions, topography, residual stress state, microhardness, and metallographic structure, were evaluated to compare the effects of multi-pass. Additionally, the heat transfer in solid module was employed to simulate the temperature histories. The result shows the diameter of hardened zone keeps about 1000 μm with the increase of multi-pass. It indicates that there was no notable additional thermal effect observed as the number of passes in the temperature histories increased. Meanwhile, the maximum microhardness of the multi-pass processed samples increases by more than 5 % in cross-sectional direction. This increase can be attributed to the occurrence of multiple rapid re-austenitization processes, which lead to a significant refinement in grain sizes and a more uniform distribution. Therefore, this particular method can be recognized as an effective approach for improving surface quality, i.e., reducing remelting, regulating geometrical parameters, ameliorating the 3D topography of the hardened area, increasing the uniformity of the hardened layer, and reducing the tensile residual stress.

A latened catalytic strategy for low cure thermoset powder coating by post-dry-blending technique

Conventional thermoset powder coatings typically require curing at a high temperature of 190 °C for a minimum duration of 15 min, which poses challenges when applying them to heat-sensitive substrates and results in elevated energy costs. A solution known as low-temperature-curing powder coating (LCPC) has been developed to address this issue. By normally incorporating the curing catalyst into the coating system via hot extrusion, LCPC can achieve either a reduced curing temperature or a shortened curing period. However, the current extrusion method used for catalyst incorporation leads to undesirable side effects, such as compromised surface quality, shorter shelf-life and a narrower operational window for the hot-extrusion process involved in producing powder coatings. To overcome these challenges, a new strategy is proposed in this study, in which the tailor-made nano-catalyst is post-dry-blended into the powder coating instead of subjecting it to hot treatment with coating ingredients. This dry-blending catalyst (DBC), encapsulating nanosized fumed silica with catalysts by impregnation method, is introduced to the powder coating system before spraying, eliminating the need for hot-kneading into the powder coating system at the beginning. The DBC is attached to the surface of the particle realizing the interparticle contact mode and latening the catalysis. The dry-blended low-temperature-curing powder coating (DB-LCPC), containing a 0.03 % dosage of onium salt and 0.035 % of 2-methylimidazole, is identified as the optimum formulation due to its excellent surface quality, prominent chemical and mechanical characteristics. The sample successfully achieved low-temperature curing or a shortened curing time while maintaining excellent mechanical properties and chemical resistance. Furthermore, it exhibited superior coating appearances and a longer shelf-life compared to the hot-extruded sample. This novel DBC method has the potential to greatly enhance the adoption of low-temperature-curing powder coatings.

INNOVATIVE METHODS OF MONITORING THE MECHANICAL PROCESSING PROCESS

The problem of ensuring the necessary quality and exploitation of the properties of machine parts is becoming more and more important in mechanical engineering. The main idea of the work consists in the development of a fundamentally new approach to the monitoring of a machine tool complex of mechanical processing, the essence of which is the organization of the method of controlling the mechanical processing process on the basis of a single integrated information environment adapted to the universal complex of computer modeling Matlab/Stateflow and Matlab/Simulink, with structural representations of all components of the mechanical processing process and modeling as a problem-solving tool that expands the functionality of machine tool complexes. However, until now, generalized theoretical relationships between surface quality parameters, processing accuracy, operational properties of parts and parameters of mechanical processing processes, which allow solving the problem of technological support of given operational properties of parts. Management of the process of forming a surface with the necessary properties is carried out mainly by using partial experimental dependencies and tables of processing modes. The complexity of the problem lies in the fact that when processing parts, it is necessary to establish such processing conditions that would provide a set of requirements for tool wear, processing accuracy, surface quality characteristics, productivity, etc. The areas of the most effective use of production systems are primarily determined by the technological equipment that is a component of the system, the nomenclature of processed parts and the automated control system. which allow to solve the problem of technological provision of given operational properties of parts.

Atomic force microscopy analysis on Hardox alloy using LBM process

Atomic force microscopy (AFM) analysis plays an essential role to investigate the surface investigation of alloy and different composition of materials. The surface quality characteristics of the alloys depend upon the different AFM surface factors. The present paper discusses the surface investigation on laser beam machined area of the hardox steel 450. The surface quality of the machined component is depends on the different alloying element present in the composition. Laser power, cutting speed and pulse duration of the LBM factors were used to enhance the surface profile. The surface was analyzed at laser power of 1500, 2000, 2500 W, cutting speed of 800, 900, 1000 mm/min and pulse duration of 50,100,150 ns. The moderate surface roughness was attained for Hardox steel at medium level of LBM factors. Average roughness of 15.17 µm was attained at laser power of 2500 W, cutting speed of 1000 mm/min and pulse duration of 150 ns.

Modeling and Optimization of Surface Quality Characteristics in Electrochemical Surface Grinding of Metal Matrix Composite

Modeling and Optimization of Surface Quality Characteristics in Electrochemical Surface Grinding of Metal Matrix Composite

Development and research of syntactic foams for antenna devices parts manufacture

Foam plastics are always widely used in antenna-feeder systems due to the low values of the dielectric constant ε and the tangent of the dielectric loss angle tgδ. Structural elements of such antennas are usually made by gluing blanks cut from expanded polystyrene plates or from filling polyurethane foam. However, these methods turned out to be low-tech due to the high labor intensity of the process, the inhomogeneity of the dielectric properties of structures and the unsatisfactory quality of the painted surface due to the low chemical resistance of these materials to solvents of paint and varnish materials. Syntactic foams, which are a special type of gas-filled polymers, in which hollow spherical filler particles are distributed, in comparison with traditional foams, have increased mechanical strength, electrical strength, resistance to climatic factors, less density difference and better surface quality. It is the advantages of syntactic foams listed above that make them relevant materials in the manufacture of structural elements of antennas. The purpose of the work is to study the possibility of obtaining products from low-density syntactic foam by combining an expandable polymer matrix with a filler in the form of hollow glass microspheres. The limits of filling the polymer matrix by the filler have been established. The material dielectric characteristics (dielectric constant ε and the tangent of the dielectric loss angle tgδ) and strength (compression stress at 10% deformation) characteristics have been investigated. The resistance of the material to the influence of climatic factors has been investigated. The technology of manufacturing the product by the flooding method has been developed. Also the effect of paint and varnish coatings on surface quality and dielectric characteristics of foams of low density has been investigated. The obtained results can be used to create structural elements of antennas.

Optimization of multiple surface roughness characteristics of mild steel turned product using weighted principal component and Taguchi method

This paper presents a hybrid approach utilizing Principal Component Analysis (PCA) integrated with the Taguchi Method to address a multi-criteria optimization problem in the turning process of a cylindrical mild-steel workpiece using a High-Speed Steel tool. Suitable turning process parameters are identified to comply with multiple requirements and assessment of surface quality. The traditional Taguchi method has limitations in solving multi-criteria optimization problems since quality characteristics need to be uncorrelated or independent. To overcome this, PCA was employed to identify independent or uncorrelated quality indices named Principal Components. The study demonstrates the feasibility of PCA and the Taguchi method to forecast an optimal parameter setting for assessing surface quality, followed by confirmatory tests. This paper showcases the mix of PCA and Taguchi methods for multi-criteria optimization and off-line control of correlated multiple surface quality characteristics in turning processes.

Provision of Rational Parameters for the Turning Mode of Small-Sized Parts Made of the 29 NK Alloy and Beryllium Bronze for Subsequent Thermal Pulse Deburring.

The increase in the share of physical and technical processing methods in the arsenal of deburring technologies used in modern production is associated both with the use of difficult-to-machine materials, such as beryllium bronze and the 29 NK alloy, and with the need to solve technological problems for the production of small-sized products with hard-to-reach surfaces. The aim of the study is to improve the processes of blade processing of small-sized parts made of beryllium bronze and the 29 NK alloy to provide rational conditions for thermal pulse deburring. Surface samples were experimentally obtained after turning in different modes on a CITIZEN CINCOM K16E-VII automatic lathe equipped with an Applitec micromechanics tool. The surface quality and burr characteristics were examined using a JEOL JIB-Z4500 electron microscope and a ContourGT-K optical profilometer. The program Statistica 6 allowed processing of the results. The relationship between the parameters of the turning mode and the thickness of the root of the burrs formed on the machined surface, the limitation of which is one of the conditions for the application of the thermal pulse method, was established. The obtained empirical regression dependencies establish a rational range of cutting mode parameters, and the implementation of the formulated recommendations for setting blade modes ensures deburring by the thermal pulse method in compliance with the requirements of drawing under maximum processing performance.

Cutting Parameters Optimization for Minimal Total Operation Time in Turning POM-C Cylindrical Stocks into Parts with Continuous Profile Using a PCD Cutting Tool

Turning is a complex machining process that can be characterized by a number of performances for a given machining system, workpiece material, cutting tool, and selected cutting regime. In addition to the characteristics of the machined surface quality, the estimation of machining time is particularly important for manufacturers, since machining time is directly related to other important performances of the turning process, such as productivity, cost, and energy consumption. In this paper, a model for estimation of total operation time in turning of a part with continuous profile, made of polyoxymethylene copolymer (POM-C), using a polycrystalline diamond (PCD) cutting tool, was developed. Face centred central composite design (CCD) and Box–Cox transformation approaches were applied for that purpose. The developed model was then used as the objective function in the proposed optimization model, which also included three practical constraints related to quality of the machined surface (surface roughness and workpiece deflection) and machinability aspects of the workpiece material (favourable chip forms). Nonlinear and linear models, used as constraints, were developed based on the results of experimental investigation of turning of POM-C using a PCD cutting tool. The total operation time estimation model showed good agreement with the results of tool path simulations in CAM software and validation experimental trial in real manufacturing environment. By applying the optimal solution, 44% of the total time being saved for machining of a single part can be achieved, compared to the recommended cutting parameter values, which indicates significant optimization benefits in turning industrial plastics.

Dimensioning of the Clearance as a Means of Avoiding Burr and Film Formation during the Punching of PC/ABS Cable Ducts

The production of staple articles such as cable ducts offers reductions in resource and production energy consumption if the process is optimized. Side recesses made of polyvinyl chloride (PVC) have already been punched successfully as one of the process steps during the production of cable ducts. However, punching cable ducts made of flame-retardant polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) is challenging because increased burr and film formation occurs. This study introduces the correct dimensioning of the clearance as a means of reducing the burr and film formation and presents the ideal clearance dimensions. This new process design approach comprises the dimensioning of the clearance and its subsequent successful application. Tools with clearances in the relevant size range were purchased and examined by means of punching tests. The punch-outs were evaluated regarding the quality characteristics, such as the burr, film, cut surface quality, shear droop, and plastic flow characteristics. Excerpts from high-speed recordings were used to assess the punch-outs qualitatively. The burr formation is significantly decreased by the use of a correctly dimensioned clearance, allowing for the crack initiated at the punch side and the crack initiated at the die side to meet perfectly. It is assumed that film formation can be avoided via a significant reduction in the friction or heat input during the punching process.

Enhancing the Surface Quality of FDM Processed Flapping Wing Micro Mechanism Assembly through RSM–TOPSIS Hybrid Approach

Improving surface quality attributes is a critical task in the production of micro-sized near-net-shaped components for end-use applications using additive manufacturing techniques. In the present study, we investigated the effect of fused deposition modeling (FDM) process parameters such as layer thickness, part orientation, raster width and raster angle on the surface quality characteristics of as-fabricated test specimens in order to develop the assembly of a flapping wing micro mechanism. Through a Box–Behnken design, a suitable experimental strategy was developed, and test specimens were manufactured. The performance of the experiments was statistically assessed using multi-response analysis of variance (ANOVA). The microstructures of the test specimens produced with various processing parameters were examined using a scanning electron microscope to identify micro surface flaws under various processing conditions. Furthermore, the optimal FDM parameters for improved surface quality attributes such as Ra, Rz and Rq were obtained using a statistical optimization technique known as Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS).

Effect of Heat Treatment on the Resulting Dimensional Characteristics of the C45 Carbon Steel after Turning

The presented article deals with the influence of the heat treatment of C45 steel on the surface quality after turning. Turning is a machining technology used to prepare specific geometrical characteristics of surface and dimensional quality. In the present paper, the same turning conditions were used for the turning treatment of differently heat-treated steels. The soft annealed state, normalized state, hardened state, quenched and tempered at 530 °C state and quenched and tempered at 660 °C state have been analyzed. By using this approach, it has been possible to evaluate the effects of hardening and machining on the resulting parameters after turning (roughness, cylindricity and circularity). The highest hardness was observed in the steel after the hardening process (694 ± 9 HV 10). The hardening has negatively influenced the surface quality. The high hardness was related to martensite formation and caused a damage to the cutting edge of the cut insert used, leading to a significant change in geometrical accuracy. The cylindricity change achieved 0.15 ± 0.03 mm which was significantly higher compared to the theoretical value of the diameter of the machined steel bar. An inaccuracy was also observed in diameter dimension. These inaccuracies were caused by the wear of the cutting edge of the tool used in cutting parameters setting.