Axial Feeding Speed Research Articles

Grinding Force Model and Experimental Study on Ultrasonic Assisted Spiral Grinding of Silicon Carbide Ceramic Materials

In order to reveal the mechanical properties of silicon carbide ceramic materials during the drilling process, based on the indentation fracture mechanics theory, a grinding force model of ultrasonic assisted spiral grinding for hole making was established, and the experimental results of ultrasonic assisted spiral grinding for hole making verified the mechanical model. The results showed that the experimental results had the same change trend as the predicted results of the established mechanical model, and the values were close to each other, indicating the accuracy of the established prediction model. The influence of different process parameters on the size accuracy of the hole inlet and outlet aperture after machining is analyzed. It is found that it should be selected as large rotation speed, moderate axial feed speed and small feed pitch to ensure the accuracy of the aperture and effectively suppress the aperture defects during ultrasonic assisted spiral grinding.

Parametric analysis of tooth surface characteristics of flexspline in harmonic reducer after hobbing

The accurate prediction of tooth surface morphology for the flexspline in harmonic reducers after hobbing is a crucial technology for achieving high-precision harmonic gearing. This study investigates the impact of process parameters on the tooth surface characteristics of the flexspline. Two models were established to study the formation of tooth surfaces using both continuous cutting with a hypothetical rack tool and interrupted cutting with a multi-cutting-edge hob. The resulting surface geometry of the models was compared, and the effect of hob axial feed, hob mounting angle deviation, and hob outer diameter size on tooth surface morphology was analyzed. The study findings indicate that the crowning of gear teeth results in overcutting on the flexspline tooth surface, which is directly proportional to the degree of crowning and hob outer diameter. Furthermore, a lower axial feed speed during the hobbing process reduces material residue, and hob mounting angle deviations can lead to overcutting on one end of the tooth surface and material residue on the other end.

A Study on the Effect of Gear Hobbing Process Parameters on the Residual Stress of the Tooth Root

The root residual stress during gear machining has a significant impact on the bending fatigue performance of the gear. The process parameters of gear hobbing (hob speed, axial feed speed, and radial cutting depth) directly affect the residual stress of the tooth root. To investigate the relationship between the process parameters of hobbing and the residual stress of the tooth root respectively, an analysis of an orthogonal and single factor was conducted in the hobbing experiment, taking into account the interactions among factors, which revealed the influence rule and primary–secondary relationship of the process parameters on the residual stress of the tooth root. The importance coefficients of the process parameters on the residual stress of the tooth root were calculated using the Least Absolute Shrinkage and Selection Operator (LASSO) method. The results indicate that the residual tensile stress at the tooth root increases with an increase in the hob speed and axial feed speed within the selected range but decreases with an increase in the radial cutting depth. The influence of the process parameters on the residual stress of the tooth root can be ranked as follows: hob speed (importance coefficient 0.460), axial feed speed (importance coefficient 0.278), and radial cutting depth (importance coefficient 0.262). This research provides a basis for improving the residual stress of the tooth root and enhancing the anti-fatigue manufacturing of gears, thus holding significant research value.

Simulation Analysis of Torsion Beam Hydroforming Based on the Fluid-Solid Coupling Method

Hydroformed parts are widely used in industrial automotive parts because of their higher stiffness and fatigue strength and reduced weight relative to their corresponding cast and welded parts. This paper reports a hydraulic-forming experimental platform for rectangular tube fittings that was constructed to conduct an experiment on the hydraulic forming of rectangular tube fittings. A finite element model was established on the basis of the fluid–solid coupling method and simulation analysis. The correctness of the simulation analysis and the feasibility of the fluid–solid coupling method for hydraulic forming simulation analysis were verified by comparing the experimental results with the simulation results. On the basis of the simulation analysis of the hydraulic process of the torsion beam using the fluid–solid coupling method, a sliding mold suitable for the hydroforming of torsion beams was designed for its structural characteristics. The effects of fluid characteristics, shaping pressure, axial feed rate, and friction coefficient on the wall thicknesses of torsions beams during formation were investigated. Fluid movement speed was related to tube deformation. Shaping pressure had a significant effect on rounded corners and straight edges. The axial feed speed was increased, and the uneven distribution of wall thicknesses was effectively improved. Although the friction coefficient had a nonsignificant effect on the wall thickness of the ladder-shaped region, it had a significant influence on a large deformation of wall thickness in the V-shaped area. In this paper, a method of fluid-solid coupling simulation analysis and sliding die is proposed to study the high pressure forming law in torsion beam.

A Novel Heat-Assisted Three-Roll Incremental Rolling System for Flexible Rolling

Abstract The increasing demand for customized products and rapid prototyping triggers the development of dieless forming process where the need of part-specific dies is eliminated compared to conventional forming processes. This paper presents a heat-assisted three-roll incremental rolling system capable of producing rods and tubes of various diameters without the need for die/tool replacement. The system incorporates two possible heating mechanisms, namely, an induction heater and a high-current power supply for electrically assisted forming. Due to its high flexibility and hot forming ability, this rolling system is ideal for low volume production or scientific research. The newly fabricated rolling machine was initially evaluated using low carbon steel rods. The experiments have shown that the machine can produce metallic rods down to 6 mm in diameter without apparent spiral marks on the outer surface of the rolled product using multiple passes. The finite element method (FEM) was used to analyze the reaction moment, depth of the spiral marks, and the effect of axial feeding speed on the spiral marks. The simulation model predicted the results of the experiments with less than a 10% error. The work established a flexible rolling platform for possible future research, which can include the study of interface behavior in the thermo-mechanical rolling processes, and the study of material behavior in this multi-axial multi-physics environment.

An analytical method to control and predict grinding textures on modified gear tooth flanks in CNC generating gear grinding

• A method to control and predict gear surface texture is proposed. • Both dressing and grinding motions are considered in generating gear grinding. • Oblique direction of texture patterns on gear tooth flanks is adjustable and predictable. • Gear tooth topology modification with oblique grinding texture is achievable. Natural motion in generating gear grinding often produces regular and mutually-parallel gear grinding texture, which induces higher pure-tone gear meshing noise than that with an irregular texture generated by gear honing. This study presents a generation method of irregular and oblique grinding texture on modified gear tooth flanks considering both dressing and grinding motions in a CNC generating gear grinder. The grinding texture is controllable via an additional installation angle between the grinding wheel and the work gear axes. Meanwhile, the gear tooth flank deviation caused by this variation is corrected by additional motions of machining axes . The sensitivity matrix (SM) combined with the Levenberg-Marquardt (LM) algorithm is employed to determine the additional motion functions. In numerical examples, effects of axial feeding speed, abrasive grain size, and installation angle variation on texture patterns and their mean roughness are investigated, respectively. A crowned tooth flank with irregular and oblique grinding texture is also demonstrated to prove the reasonability and validity of the proposed method.

Prediction of surface roughness and delamination in spiral milling of CFRP laminates by SAPSO-BP neural network

Due to the anisotropy carbon fibre reinforced polymer (CFRP) materials, problems such as poor surface quality of the hole wall and delamination often occur in the traditional hole-making process. In this study, the Taguchi method was used to design a CFRP spiral-milling experiment using uncoated and diamond-coated carbide cutters. The analysis of variance and signal-to-noise ratio analysis were used to study the influence of process parameters on the surface roughness and delamination factors. Prediction models for surface roughness and delamination factors were established using improved particle-swarm neural network. The results showed that the diamond-coated milling cutters are more suitable for CFRP processing. The order of importance of the process parameters is as follows: axial-feed speed > horizontal-feed speed > spindle speed > revolution radius. The prediction model for the surface roughness and delamination factors developed in this study achieves high accuracy.

Prediction of surface roughness and delamination in spiral milling of CFRP laminates by SAPSO-BP neural network

Due to the anisotropy carbon fibre reinforced polymer (CFRP) materials, problems such as poor surface quality of the hole wall and delamination often occur in the traditional hole-making process. In this study, the Taguchi method was used to design a CFRP spiral-milling experiment using uncoated and diamond-coated carbide cutters. The analysis of variance and signal-to-noise ratio analysis were used to study the influence of process parameters on the surface roughness and delamination factors. Prediction models for surface roughness and delamination factors were established using improved particle-swarm neural network. The results showed that the diamond-coated milling cutters are more suitable for CFRP processing. The order of importance of the process parameters is as follows: axial-feed speed > horizontal-feed speed > spindle speed > revolution radius. The prediction model for the surface roughness and delamination factors developed in this study achieves high accuracy.

Abrasive jet turning of glass and PMMA rods and the micro-machining of helical channels

This paper investigates the use of air-driven abrasive jets as a lathe and as a means of machining helical patterns into rotating rods. The first part of the paper presents a model for the prediction of material removal during the machining of rotating and translating ductile (PMMA) and brittle (glass) rods using abrasive jet micromachining (AJM). The model predictions were in good agreement with the experimental measurements, showing that, for a given particle speed, the volumetric removal was only a function of the abrasive dose received by the surface, and was unaffected by the rod diameter, its rotational speed, and the axial feed speed. The second part of the paper presents a new experimental procedure for machining helical channels in glass and PMMA rods using a cylindrical steel spring as a mask. Such helical channels may have applications in microfluidic devices where they can be used to aid liquid mixing and the separation of particles from a flow. The use of spring masks at various pitches and the control of the exposure time of the jet to the workpiece made it possible to fabricate helical channels with a wide range of aspect ratios, from 0.09 to 1.2. High curvature, which is favorable in the microfluidic separation of particles, was achieved by machining rods of small diameter. In addition to microfluidic applications, the models and techniques can potentially be used to machine threads in glass and other difficult to machine materials.

Material removal rate for nanocomposite ceramics in ultrasound-aided electrolytic in process dressing

Nanocomposite ceramics possess beneficial mechanical and physical characteristics over traditional engineering ceramics; however, there is currently no effective method of machining nanocomposites ceramics. This paper proposes a new ultrasound-aided electrolytic in-process dressing machining method. There are many factors influencing the material removal rate in the ultrasound-aided electrolytic in-process dressing grinding. In order to optimize the processing parameters and guide practice, the material removal models are developed to simulate the material removal process based on ductile failure and brittle rupture models, and the influence of grinding parameters on material removal rates is obtained. With the model, the influence of grinding parameters on the material removal rate is analyzed by MATLAB. The analysis results are verified by the ultrasound-aided electrolytic in-process dressing grinding test: the material removal rate increases with the increase of grinding parameters; depth of cut significantly improves material removal rate, followed by axial feeding speed, wheel speed, and workpiece speed that are less important; considering the comprehensive processing effect, depth of cut is the key parameter with the optimal setting at about 3.73 µm. The ultrasound-aided electrolytic in-process dressing grinding test not only proves the reliability of the model, but also proves that the ultrasound-aided electrolytic in-process dressing grinding can improve the ductile machining effect, when compared to electrolytic in-process dressing grinding, which is suitable for mirror machining of the nanocomposite materials.

Grinding Parameter Optimization of Ultrasound-Aided Electrolytic in Process Dressing for Finishing Nanocomposite Ceramics

In order to achieve the precision and efficient processing of nanocomposite ceramics, the ultrasound-aided electrolytic in process dressing method was proposed. But how to realize grinding parameter optimization, that is, the maximum processing efficiency, on the premise of the assurance of best workpiece quality is a problem that needs to be solved urgently. Firstly, this research investigated the influence of grinding parameters on material removal rate and critical ductile depth, and their mathematic models based on the existing models were developed to simulate the material removal process. Then, on the basis of parameter sensitivity analysis based on partial derivative, the sensitivity models of material removal rates on grinding parameter were established and computed quantitatively by MATLAB, and the key grinding parameter for optimal grinding process was found. Finally, the theoretical analyses were verified by experiments: the material removal rate increases with the increase of grinding parameters, including grinding depth (ap), axial feeding speed (fa), workpiece speed (Vw), and wheel speed (Vs); the parameter sensitivity of material removal rate was in a descending order asap>fa>Vw>Vs; the most sensitive parameter (ap) was optimized and it was found that the better machining result has been obtained whenapwas about 3.73 μm.

Research on models of design and NC manufacturing for ellipsoid end mill

This paper presents a new kind of cutting tool named as ellipsoid end mill to raise machining efficiency in numerical control (NC) milling. Two types of ellipsoid end mills are developed, i.e. cylindrical ellipsoid end mill and tapered ellipsoid end mill. Three models of cutting edges (the cutting edge with constant helix angle, the orthogonal spiral cutting edge and a novel cutting edge) are established, and the corresponding numerical simulation results are also provided in graphical representation, respectively. Manufacturing mathematical models in 2-axis NC machining are established in detail for ellipsoidal end mill. The axial feed speed and the radial feed speed for 2-axis NC machining are determined accurately. Mathematical model of grinding wheel’s profile in 2-axis NC machining is provided, as well as correlative computer simulation results. Computer simulation results demonstrate the veracity of these mathematical models. An ellipsoid end mill is manufactured to verify the feasibility of ellipsoid end mill. Finally, a contrast experiment is provided to verify the applicability of ellipsoid end mill (EEM) and the advantage of EEM compared with ball end mill.

Research on simulation and experiment for surface topography machined by a novel point grinding wheel

Grains motion path will be changed in the point grinding process due to the existence of variable angle α. To verify the difference between point grinding and traditional grinding, the moving relationship and coordinate transformation between grinding wheel and workpiece are used to put the grain movement function equivalent to parabola, then point grinding cutting path is concluded. Based on grains distribution on the grinding wheel surface, the 3D geometry simulation topography of workpiece is obtained by extending the effective interference trails along the axial direction. Furthermore, a vitrified bond CBN wheel with a coarse grinding area angle θ is proposed and the principle of design and preparation of these novel grinding wheels are studied. The typical processing parameters are chosen to grind QT700 ladder shaft; the simulation results are verified by using the VHX-1000E microscope and the non-contact 3D surface profilometer to observe the workpiece surface topography and measure the surface roughness. The results indicated that the simulation microstructures coincide well with the experimental measurements and the values of simulation roughness are 0.5 times of experiments. So, the geometric simulation model provided an auxiliary and prediction method for the actual processing topography analysis. In addition, grinding wheels with different θ are used to grind ladder shafts with a series of grinding parameters. The influence trend of inclining angle α, cutting depth ap, axial feeding speed vf and grinding wheel speed vs on surface roughness is obtained. It is concluded that the values of workpiece surface roughness using novel grinding wheel are less than using the traditional grinding wheel under the condition of the same processing parameters.

Air Bulging을 이용한 열간 알루미늄 성형에 관한 연구

Hot tensile tests were conducted at different temperatures ranging from <TEX>$20^{\circ}C$</TEX> to <TEX>$550^{\circ}C$</TEX> to evaluate the mechanical properties of Al5052 seamless tubes. Such tubes can provide the technological foundation for complex forming using hot air bulging. Hot air bulging is one of the recently developed hydroforming techniques and it has some limitations in terms of cycle times. The benefits of hot air bulging are weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. In order to extend the forming limits of Al lightweight material hot air bulging was investigated. A heated tube was placed in a heated die and sealed at the ends by sealing cylinders. The heated tube was subsequently expanded against the die cavity wall by internal pressure using air medium. The results of the current study show that axial feeding speed and air pressure have an effect on the formability of Al tubes during air bulging at elevated temperatures.

Experimental Research on the Predictive Model for Surface Roughness of Titanium Alloy in Abrasive Belt Grinding

Titanium alloys have been applied to aerospacemedical and other fields. The surface roughness of titanium alloy about these areas is very high. Based on the results of orthogonal test, belt grinding surface roughness prediction model of TC4 Titanium alloy is established using linear regression method. The significant tests of regression equation are conducted and proved that the prediction model has a significant. The results indicate that the model has reliability on the prediction of surface roughness, abrasive belt grinding pressure has certain influence on the surface roughness, and grain size of belt and the belt linear speed have high significant influence on surface roughness and the influence coefficient are-0.9378 and-0.2317. While the contact wheel hardness and workpiece axial feeding speed have no significant influence on surface roughness.

Study on the Correlative Mechanism of Super High-speed Point Grinding

By combining super high-speed grinding and point grinding technologies,a comprehension of super high-speed point grinding and its correlative technologies is given. Models of grinding wheel wear and loading are built. It is found that the point grinding wheel has more even loading,longer life and better grinding performance in comparison to the traditional cylindrical grinding. In the chip formation test of single abrasive grain under the condition of point grinding parameters,it is found that the actual cutting depth of abrasive grain is less than the theoretical one,and the reasonable explanation is given by the chip formation mechanism of single abrasive grain. From the analysis of successive chip formation mechanism of wheel and the motion trajectory of wheel relative to the workpiece,it is found that the workpiece axial feed speed should be lower than the critical value of the least rotary-cutting cycles for ensuring fine grinding surface. Point grinding is a superior rotary-cutting process which can realize large cutting depth,high material removal rate and good surface quality. As wheel spindle swivels,the grinding zone between wheel and workpiece is not closed,it is found in wet grinding experiment that there is larger grinding fluid passing though the grinding contact zone.

Research on Prediction Model of Surface Roughness in Ultrasonic Polishing Nano-ZrO&lt;sub&gt;2&lt;/sub&gt; Ceramics

The orthogonal test of surface roughness in ultrasonic polishing nano-ZrO2 ceramics was carried out in the present paper. Through the test, the influence of machining parameters on the surface roughness was investigated. The test results showed that the influence of abrasive size on surface roughness is the most remarkable, and the other important factors are the depth of cut, on/off work situation of ultrasonic generator, axial feed speed, and working table speed in turns. Furthermore, through the regressive analysis of test data, an empirical formula of surface roughness was established to select reasonable polishing parameters.

Researches on the ring stiffness condition in radial–axial ring rolling

The radial–axial ring rolling technology is used mainly to manufacture large rings in many industrial fields. During rolling process the ring may be collapsed or deformed unexpectedly under the pressure of guide roll, and in this case the ring is wasted. To prevent ring collapsing is necessary for smooth rolling. On the basis of rolling theory, the forces exerted to ring in radial–axial ring rolling process were analyzed, and the stiffness model of ring was proposed. The stiffness condition was derived and the influencing factors of ring stiffness condition were explained. The ring stiffness condition in radial–axial ring rolling is related to the factors of ring size, rolling ratio, position angel of guide roll, rolls sizes, position of cones, radial and axial feed speed and friction condition. The effect laws of some factors on ring stiffness condition were revealed by FEM simulation. The stiffness condition can be used as a rule of design and manufacturing for radial–axial ring rolling.

The Hydroforming of Micro-Square Tubes With Non-Equal Section and Dendritic Shape

Currently, tube hydroforming and metal micro-forming technique have emerged as the attractive and important developing tendencies in industry. Hence, in this study, the finite element simulation technique was employed to investigate the micro-hydroforming for making the micro-square tube with non-equal section and dendritic shape from square tube. Results of the current study show that the deformation of micro-square tube can be effectively analyzed by finite element simulation. The bulging and wall thinning of the tube are severely influenced not only by the internal hydraulic pressure but also by the punch axial feeding speed.