Face Roughness Research Articles

Improvement Productivity and Quality by Using Lean Six Sigma: A Case Study in Mechanical Manufacturing

Intelligent integrated production systems are always of interest to production planners. However, in order to deploy and improve from a mere processing fac- tory to a processing factory with an integrated intelligent production system, it requires a team of employees, engineers, and managers to always have a spirit of innovation, continuously improving existing semi-automatic equipment into automatic ones, aiming to move towards a smart factory. The result of this research is to reduce waste in the process of assembling mechanical products by applying the DMAIC process (Define, Measure, Analysis, Improve, Con- trol), lean six sigma tools, the test of variance, hypothesis testing and exper- imental design, IBM SPSS 2020, Matlab2019a and Minitab 18 software are used for data analysis and Solid work software is used to design and simulate mechanical parts. This study shows a systematic approach to analysis to find the root cause of defects in the product assembly process, a method of diag- nosing defective products as well as the application of charts to the analysis of waste products, and improving quality by applying basic quality manage- ment tools such as Pareto charts, fishbone diagrams, value stream mapping, man-machine chart, and failure tree analysis (FTA). Clearly identify the types of waste such as components sliding on top of each other without rust, and sur- face roughness of metal products that do not meet the standards. Experimental design models and statistical models, and statistical tests are applied to Lean six sigma’s DMAIC model in the process of analyzing the machining process. The results of analysis and process improvement have improved in a reduc- tion of scrap in the assembly line of mechanical products by 59.66% per year, an increase in assembly-line productivity by 7.8% per year, and a decrease in waste costs incurred by 59.66% per year. The application of the DMAIC cycle to improve the quality of the assembly line of mechanical products, in addition to reducing waste, also reduces the quality cost of the assembly line.

The Effect of Different Surface Treatments to Reduce Surface Roughness Before PVD Coatings

Abstract: Titanium and its compounds are used in aerospace, automotive, and chemical but currently it's considerably used in biomedical usages due to its excellent combination of low viscosity, high strength to weight rate, high erosion resistance, and biocompatibility, still, the main limit is poor tribological parcels therefore it can not be successfullyused.Wide range of face treatments disposition of shells similar as scraping and melting of face and cumulative processes similar as plating. For essence, face variations are plating or sheeting processes. There are different types of face coatings charging, electrochemical coatings, vapor deposit, conversion coatings, and thermal spraying among them PVD is vapor deposit which the coatings are hard and thin film. In PVD coatings Nitrides and carbide coatings are classified. In which nitride coatings TiN, TiAlN, and duplex TiAlN and drum were deposited on a substrate( Ti6Al4V). But for deposit, the face roughness should be0.08 µm. Thin hard coatings have good wear and tear resistance only when they've good adhesion and certain face roughness. To reduce face roughness different face treatments are acclimated similar as shot firing, sandblasting, drawing, ray figure, grinding and polishing, etc. Sandblasting was done but the face roughness didn't drop to0.08 µm. so required face roughness was attained by grinding and polishing with sandpaper, and it was diamond polished

Preparation of Cemented Carbide Insert Cutting Edge by Flexible Fiber-Assisted Shear Thickening Polishing Method.

Reasonable cutting edge preparation can eliminate microscopic defects and improve the performance of a cutting tool. The flexible fiber-assisted shear thickening polishing method was used for the preparation of cemented carbide insert cutting edge. The influences of the polishing angle and polishing speed on the cutting edge preparation process were investigated, and the cutting edge radius and K-factor were employed as evaluation indexes to evaluate the edge shape. A prediction model of the cutting edge radius was also established using the mathematical regression method. The results show that the polishing angle has a more significant effect on the cutting edge radius. The cutting edge preparation efficiency is the highest under the polishing angle of 10°, and the cutting edge radius increased from the 15 ± 2 μm to 110 ± 5 μm in 5 min. The cutting edge shape can be controlled by adjusting the polishing angle, and the K-factor varies from 0.14 ± 0.03 to 0.56 ± 0.05 under the polishing angle (from −20° to 20°). The polishing speed has a less effect on the cutting edge radius and shape, but increasing the polishing speed within a certain range can improve the efficiency of cutting edge preparation. The flank face roughness decreased from the initial Ra 163.1 ± 10 nm to Ra 5.2 ± 2 nm at the polishing angle of −20°, which is the best polishing angle for the flank face surface roughness. The ANOVA method was employed to evaluate the effective weight of the polishing angle and polishing speed on preparation efficiency. The polishing angle (86.79%) has the more significant influence than polishing speed (13.21%) on the cutting edge preparation efficiency. The mathematical regression method was used to establish the model of the prediction of the cutting edge radius with polishing angle and speed, and the models were proved rationally. The results indicate that the FF-STP is an effective method for the high consistency preparation of cemented carbide insert cutting edge.

Evaluation of flexural strength, surface roughness & water sorption of flexible denture base and conventional heat cure denture base materials- An invitro study

Since periods, polymethyl methacrylate (PMMA) has been used to fabricate the dentures. The acrylic denture base prostheses have their own advantages and disadvantages. Innovation of Flexible dentures are an excellent volition to conventionally used methyl methacrylate dentures, which not only give excellent aesthetics and comfort but also acclimatize to the constant movement and inflexibility in incompletely edentulous cases. This study has been accepted to estimate and compare the Flexural strength, face roughness and water sorption of two flexible denture base resins i.e. Valplast, Macroflexi and a heat cure denture base resin Acralyn-H. Hence, the objective of this study was to compare & estimate the Flexural Strength, Surface Roughness and Water sorption of two different Flexible denture base accoutrements and Heat cure denture base material. Twenty test samples of each material were divided into Group- A, Group- B, Group- C independently which were used for Flexural strength test and face roughness testing. Water sorption values were calculated using the formula and attained.

Challenges, Opportunities and Analysis of the Machining Characteristics in hybrid Aluminium Composites (Al6061-SiC-Al2O3 ) Produced by Stir Casting Method

Metal matrix composites of Aluminium are finding increasing applications across a wide range of industries, including the automotive and aerospace industries, amongst others. When a third constituent is added to the metal matrix, the production of the hybrid compound commences. This body of work presents the findings of an investigation into the surface roughness properties of hybrid aluminum metal matrix (Al6061-SiC-Al2O3) composites. Some exper- imental investigations were carried out using a lathe. The stir casting method is a technique employed in the field of liquid metallurgy. In this technique, the base matrix was infused with 4, 8, and 12 percent by weight of SiC and Al2O3 particles, respectively. This allowed for the production of composites. The end-result cast composites were handled with a great deal of care and atten- tion to detail. The parameters such as feed rate, cutting speed, and depth of cut that are known to influence surface roughness were investigated. The findings of the study demonstrated that an increase in feed rate leads to a rise in sur- face roughness, but an increase in cutting speed leads to a decrease in surface roughness.

Ultimate Bearing Capacity of Ring Foundations Embedded in Undrained Homogeneous Clay

A ring foundation is widely used in bridges, water towers, caissons, and other engineering structures, and its ultimate bearing capacity is one of the significant concerns in engineering design. This paper is aimed at exploring the ultimate bearing capacity of ring foundations embedded in undrained clay. Based on the finite element limit analysis, effects of the inside-to-outside radius ratio, embedment depth ratio, cutting face inclination angle, and face roughness on the vertical ultimate bearing capacity of ring foundations are investigated. The results show that the ultimate bearing capacity of the ring foundation increases gradually with the embedment depth ratio. When the embedment depth ratio D / B reaches a critical value, the bearing capacity tends to be stable, and the critical embedment depth ratio is affected by the inside-to-outside radius ratio of the ring foundation, varying from 0.2 to 0.4. The ultimate bearing capacity of the ring foundation decreases with cutting face inclination angle β . When β ≤ 40 ° , the ultimate bearing capacity tends to be stable, and the bearing capacity is reduced by approximately 30%. The influence of the cutting face inclination angle on the bearing capacity is highly dependent on the roughness of the cutting face.

Bearing capacity of open caissons embedded in sand

Open caissons are an increasingly common means of constructing underground storage and attenuation tanks as well as launch and reception shafts for tunnel-boring machines. The caisson walls typically feature a tapered base, referred to as the ‘cutting face’, to aid the sinking process by reducing the vertical soil reaction. The primary aim of this paper is to explore the influence of the caisson cutting face inclination angle on the vertical soil reaction in sand. Both finite-element limit analysis and finite-element analysis are adopted for this purpose. The effects of cutting face roughness, external embedment depth and caisson radius are also investigated. The results show that the influence of the cutting face inclination angle on the bearing capacity is highly dependent on both the soil friction angle and the roughness of the cutting face. A reduction in the caisson radius is also shown to cause a significant increase in the vertical soil reaction. The numerical output is used to inform the development of a new closed-form analytical approach amenable for use in routine design. The design method is shown to provide a high-fidelity representation of the numerical output.

The effect of different surface treatments to reduce surface roughness before PVD coatings

Titanium and its compounds are used in aerospace, automotive, and chemical but currently it's considerably used in biomedical usages due to its excellent combination of low viscosity, high strength to weight rate, high erosion resistance, and biocompatibility, still, the main limit is poor tribological parcels therefore it cannot be successfully used. Wide range of face treatments disposition of shells similar as scraping and melting of face and cumulative processes similar as plating. For essence, face variations are plating or sheeting processes. There are different types of face coatings charging, electrochemical coatings, vapor deposit, conversion coatings, and thermal spraying among them PVD is vapor deposit which the coatings are hard and thin film. In PVD coatings Nitrides and carbide coatings are classified. In which nitride coatings TiN, TiAlN, and duplex TiAlN and drum were deposited on a substrate (Ti6Al4V). But for deposit, the face roughness should be 0.08 µm. Thin hard coatings have good wear and tear resistance only when they've good adhesion and certain face roughness. To reduce face roughness different face treatments are acclimated similar as shot firing, sandblasting, drawing, ray figure, grinding and polishing, etc. Sandblasting was done but the face roughness didn't drop to 0.08 µm. so required face roughness was attained by grinding and polishing with sandpaper, and it was diamond polished

Механические свойства соединений алюминиевых сплавов, выполненных сваркой трением с перемешиванием, при статическом и динамическом нагружении

On the basis of metallographic analysis and test results of samples of welded junctions of aluminum alloys AMg6 and D16T, made by friction stir welding, for static stretching, it is shown that destruction occurs in the zone of thermo-mechanical action for the AMg6 alloy and in the zone of thermal influence for the D16T alloy. At the same time, the dependence of the temporary resistance value of the welded junction on the state of the seam weld face has not been revealed. Tests for low-cycle fatigue have shown that the endurance limit is clearly dependent on the amount of seam weld face roughness. The value of the roughness of the seam weld face for the studied alloys has been determined, in which the nature of the fracture during the low-cycle fatigue test changes from multi-stage to single-stage.

Cutting shoe design for open caissons in sand: influence on vertical bearing capacity

Open caisson shafts are a widely adopted solution for a range of geotechnical applications. An external ‘cutting shoe’ is a common construction feature used to reduce the soil frictional resistance acting on the caisson during sinking. This forms an annular void encircling the caisson which is filled with a support fluid to maintain excavation stability. The primary aim of this paper is to explore the influence of the cutting shoe geometry on the resulting vertical bearing resistance in sand. Finite-element limit analysis is adopted for this purpose. Additional parameters considered in the modelling include the roughness of the caisson cutting face and cutting shoe, and the caisson radius and embedment depth. The results show that the influence of the cutting shoe is highly dependent on the caisson cutting face roughness and the soil friction angle, illustrated using detailed soil failure mechanisms. The roughness of the cutting shoe is also shown to cause a significant increase in the vertical soil reaction for large caisson embedment depths. By way of example, a recent case study in the UK, involving the construction of a 32 m dia. caisson, is used to highlight the potential influence of the cutting shoe on the bearing resistance during caisson sinking.

Study on Shear Strength of Cement Face Between Rock and Concrete

The samples of slightly weathered granite drilled before the construction of Runyang suspended bridge's north anchorage are used as the research object in this paper. Through a lot of shear strength tests of concrete-bedrock rough cement face, the influence of the cement face roughness on the shear strength, shear deformation characteristics and shear failure mechanism were systematically studied. The results show that: The post-peak stress–strain curves of smooth and rough cement faces are obviously different. The shear stress–strain curve of cement face can be generalized into 3 types. The shear stress–strain model of rough cement face is the most general form, and the smooth cement face and no cementation are its special cases. The empirical relation between cement face roughness JRC and shear strength parameters is established by the fitting of experimental data. When the cement face is climbing, the internal friction angle increases with the climbing angle. When the climbing angle is constant, the increase of cohesion is positively correlated with the ratio of fluctuation difference and wavelength. When the climbing thrust is equal to the gnawing thrust, the specimen is transformed from climbing to gnawing.

Undrained bearing capacity of the cutting face for an open caisson

Large-diameter open caissons are an increasingly common means of constructing underground storage and attenuation tanks, as well as launch and reception shafts for tunnel-boring machines. A ‘cutting face’ at the base of the caisson wall, resembling an inclined ring footing, is typically used to aid the sinking phase. This paper describes a suite of over 15 000 finite-element limit analyses exploring the bearing capacity of a caisson cutting face, partially or wholly embedded in undrained soil. The primary aim of the study is to assess the influence of the cutting face inclination angle on the vertical bearing capacity. The effects of cutting face roughness, internal overburden and surcharge, and caisson radius are also investigated. In particular, the results indicate that a steepening of the inclination angle may not always reduce the bearing capacity, if the cutting face is rough. The numerical output informs the development of a closed-form approach for application in routine design. The new design method is shown to provide an excellent representation of the numerical output.

Point diffraction interferometer with tilted waves for measuring complex surfaces

Recently, much attention has been paid to optical components with complex surfaces because they can significantly optimize the aberrations of optical systems. However, a complex surface introduces several difficulties for precise measurement. To address this challenge, we propose tilted-wave point diffraction interferometer (TPDI) for measurements of complex surfaces. TPDI combines the advantages of tilted-wave interferometry and point diffraction interferometry, thus enabling high-precision measurements of complex surfaces; moreover, this method has demonstrated good efficiency and versatility. We adopt a fiber array (FA) to generate diffractive tilted waves to compensate for the local gradient of the test specimen. Unlike the classical PDI, which focuses more on the beam quality of the on-axis diffractive wave, the proposed system requires better quality for both the on-axis and off-axis diffractive waves. Therefore, the main parameters of the FA that may introduce measurement errors are analyzed, including the end face roughness of the array, the quality of diffractive wavefronts, and the initial optical path differences. Finally, the measurement result of the high-order hyperboloid verifies that our TPDI is effective and its precision of testing a complex surface is better than λ / 37 (rms, λ = 632.8 nm).

Mixed-mode fatigue crack growth using cohesive zone modeling

In order to capture nonlinear crack tip behavior and account for mixed-mode fatigue crack growth, a cohesive zone based fatigue crack growth model is proposed in conjunction with the Park-Paulino-Roesler (PPR) traction-separation relationship. The model clearly defines five stages during arbitrary fatigue loading: softening, unloading, reloading, contact, and complete failure. The cohesive traction-separation relationship is based on the PPR fracture potential, while the fatigue damage is accumulated by introducing two conjugate damage measures. One damage measure is associated with the rate of separation, while the other is related to the rate of traction (or local stress). Additionally, two model constants are introduced to control the normal contact condition, which may be associated with physical conditions such as crack closure, crack face roughness, and oxidation of fracture surface. Furthermore, computational simulations of the proposed fatigue crack growth model are performed for a simple mode-I test, double cantilever beam test, modified mixed-mode bending test, and three-point bending test. The observed computational results lead to stable and consistent fatigue crack growth.

Chemical–Mechanical Polishing of Cemented Carbide Insert Surface for Extended Tool Life in Turning of GH4169 Nickel-Based Superalloy

To extend the tool life of conventional uncoated grinding cemented carbide inserts (CUG inserts) in turning GH4169 nickel-based superalloy, chemical–mechanical polishing (CMP) is applied to appropriately treat the rake face of the CUG insert to address the defects including grinding burn, crack, and thermal deformation. The material removal rate (MRR) and the rake face roughness Ra of YG10 chemical–mechanical polished cemented carbide inserts (CMP inserts) corresponding to the six types of abrasives particles are investigated by applying the single factor method, and the diamond powder is the most suitable to polish YG10 inserts. Thus, CMP parameters are optimized using Taguchi method coupled with both the grey relation analysis and fuzzy inference. Furthermore, the comparison experiments of the cutting performance of the CUG insert and the CMP insert in turning GH4169 are carried out, under the same cutting condition, compared with the CUG insert, the average tool life of the CMP insert is increased by 35.92%. This study demonstrates that the CMP technique is an effective potential method to improve the surface integrity, the cutting performance and the tool life of conventional uncoated grinding cemented carbide inserts & tools in the machining of difficult-to-cut materials.

Z-type shear connector for interface of hollow-core slab and cast-in-place topping concrete

Precast hollow-core slabs (PHSs) are widely used in precast construction due to their relatively low dead weight and easy assemblage. Cast-in-place topping concrete (TC) is utilized to obtain composite sections and to enhance in-plane stiffness of the slab system. Shear transfer between the layers of a composite slab can be provided by the upper face roughness of PHS. However, the roughening process may not be preferred in some plants. This paper evaluates the efficiency of Z-type shear connectors applied in the interface between PHS and TC. Three dissimilar interface conditions (i.e., Z-reinforced, smooth and rough) were studied experimentally in full-scale specimens. Push-off loading was applied to evaluate the interface shear transfer capability of the specimens, and Z-type shear connectors were found to be the most effective when they are applied at each joint between PHSs. The achievements of some code equations to assess interface shear strength were also investigated, and an alteration for the interface shear capacity equation of ACI 318M is proposed.

An efficient material removal rate prediction model for cemented carbide inserts chemical mechanical polishing

Aiming at the defects of cemented carbide inserts surfaces produced in the conventional grinding process, a cemented carbide inserts chemical mechanical polishing (CMP) process is developed to reduce the insert rake face roughness for the improvement of cutting performance. Especially, an efficient material removal rate (MRR) prediction model for cemented carbide inserts CMP is established considering synthesized effects of multi-factors characteristics such as abrasive particles, the polishing pad, and cemented carbide inserts. Firstly, the contact mechanism between the cemented carbide insert and the polishing pad is analyzed by using the Greenwood and Williamson elastic model. Then the contact model between the abrasive particle and the polishing pad is established based on the Sneddon's hyper-elastic micro-contact mechanics, and the contact model between the abrasive particle and the cemented carbide insert is built by applying the elastic-plastic micro-contact mechanics. Finally, an efficient MRR prediction model is proposed. The experimental results show that when changing the polishing pressure and the polishing disk rotational speed individually, the MRR average error between the predicted value and the experimental value is 1.65% and 2.18%, respectively. This study demonstrates that the proposed model can contribute to CMP preparation of high-performance cemented carbide tools/inserts.

On the Surface Roughness for the Dry Superfinishing Process of Carbide Inserts

The surface roughness of tool edge and surface can affect the friction, between the rake face and chips and also the cutting force and temperature. For this reasons, in order to assure a good quality, some experimental determinations, from point of view of rake face roughness, are presented in this paper. The results, as capture from a SEM microscope, and, graphically dependencies of roughness as function of process parameters, are presented.

Spiral Bevel Gears Face Roughness Prediction Produced by CNC End Milling Centers.

The emergence of multitasking machines in the machine tool sector presents new opportunities for the machining of large size gears and short production series in these machines. However, the possibility of using standard tools in conventional machines for gears machining represents a technological challenge from the point of view of workpiece quality. Machining conditions in order to achieve both dimensional and surface quality requirements need to be determined. With these considerations in mind, computer numerical control (CNC) methods to provide useful tools for gear processing are studied. Thus, a model for the prediction of surface roughness obtained on the teeth surface of a machined spiral bevel gear in a multiprocess machine is presented. Machining strategies and optimal machining parameters were studied, and the roughness model is validated for 3 + 2 axes and 5 continuous axes machining strategies.

The Influence of Surface Roughness of Cutting Inserts Made of Diamond–Tungsten Carbide Composite on Cutting Forces and Machining Quality in Turning Aluminum Alloys and Brass

The paper addresses the effect of face roughness of cutting inserts made of diamond–tungsten carbide nanocomposite on cutting forces, vibration, and machined surface quality in finish turning of aluminum alloys and brass. The authors have substantiated the optimal cutting conditions to produce workpiece surfaces with the minimum roughness and waviness.