Tool Profile Research Articles

Gear skiving with minimum twist errors

Over the last 15 years, gear skiving has established itself as a highly productive gear cutting process for the production of internal gears and gears with near interference contours. As with all processes with crossed axes, gear skiving generally results in a pronounced natural twist when gears with lead crowning or other flank modifications are produced. In practical applications, the unintended profile angle changes over the tooth width resulting from the twist leading to unwanted contact patterns and unfavorable NVH behavior. In this work, a contact line-based method for tool profile calculation for gear skiving is developed based on conical-screw gear theory. The relationship between contact line and natural twist errors is worked out. The process and tool design strategies for minimizing the twist are elaborated and finally, an adaptive process kinematics for low-twist error gear skiving is presented.

A cylindrical skiving tool design method based on a conjugate surface for internal gear manufacture

Power skiving is a highly productive method for manufacturing gears, especially internal gears. However, due to the resharpening errors of the conical skiving tool, the insufficient tool life hinders the large-scale applications of power skiving. This work proposes a novel design method of the cylindrical skiving tool based on deriving the mathematical model of two-parameters conjugate tooth surface of an internal gear. The error-free cutting-edge of the skiving tool is obtained from the intersection curve of the conjugate tooth surface and the rake face with an offset along the tool axis. In the present study, a helical internal gear with 97 teeth, module of 1.5875 mm and helix angle of 23.5° is used for the design of a cylindrical skiving tool with 37 teeth. The numerical analysis results show that the tool axial offset zoff, crossed shaft angle Σ and geometric rake angle of tool γ0 result in the asymmetrical tool profile and the uneven clearance angles on both flanks. However, the change of the tool helix angle by 0.7° can obtain an even clearance angles on both flanks when zoff is −30 mm. The noninterference height of the cylindrical tool is 48 % more than the conical tool when machining the same workpiece, which means the cylindrical tool is expected to be a longer tool life. Experiments are conducted on a Profilator Type H skiving machine by using the cylindrical skiving tool by the accuracy of DIN 3. The results show the tool design method is effective and applicable to machine a gear by the accuracy of ISO1328-1 level 7.

GEOMETRIC ANALYSIS AND DESIGN OF FLAT FORM TOOLS

Form tool means a cutting tool which is appropriate manufacturing of workpieces having more complicated geometry. The contour of manufactured workpiece is manufactured by the tool profile. This cutting tool can be used in case of serial and quantity production. The advantageous of their usage are the lower turning time and the lower standard deviation of the workpiece sizes. The reached accuracy on the workpiece is independent from the qualification of the worker. The aim of this publication is the explanation of the geometric analysis and the design by analytical and constructional way. This type of tool is advantageously usable for manufacturing on CNC machine or conventional machine.

Microstructural and micro-mechanical behaviours of friction stir processed magnesium alloy

This investigation deals with the microstructural and mechanical behaviours of friction stir processed (FSPed) commercially available pure magnesium with different tool profile geometry. The micro-level properties were assessed through in-situ micro-pillar compression which showed that FSPed material experienced significant plastic deformation and even re-distribution of residual oxide particles which was present in the cast magnesium together with grain refinement (from 3.4 μm to 2.6–2.7 μm). These changes in microstructure contributed to raise the compressive and yield strengths of the FSPed magnesium, up to 99 MPa and 94 MPa respectively, compared to 33 MPa of cast magnesium, when triangular tool profile was employed. Furthermore, the deformed material acquires ductile breakage with improved plasticity (micro-necking) irrespective of processing conditions, that is, either cast or friction stir processed.

Способ профилирования внутренних резьб при фрезеровании

Analysis of the works devoted to thread milling showed that milling of the threads with a special profile differing from the metric profile was not sufficiently studied. Based on data of the existing threads profile analysis, the paper proposes a generalized profiling scheme using the example of a round thread. The theory of envelopes of the cutting tool positions family makes it possible to analyze the shape of the resulting thread profile and the cutting tool profiling in shaping with a kinematic scheme of thread milling with the parallel thread and tool axes. Mathematical expressions are provided that allow calculating geometric error in the round thread using the proposed method and profiling a thread cutter to form the thread of the accepted accuracy degree. The specified method could be extended to a thread with any profile described by a mathematical expression in its axial plane. Study results could be useful to the developers in designing the thread mills and to the technologists to assess the possibility of using thread milling in machining threads with the round profile.

A theoretical and deep learning hybrid model for predicting surface roughness of diamond-turned polycrystalline materials

Polycrystalline materials are extensively employed in industry. Its surface roughness significantly affects the working performance. Material defects, particularly grain boundaries, have a great impact on the achieved surface roughness of polycrystalline materials. However, it is difficult to establish a purely theoretical model for surface roughness with consideration of the grain boundary effect using conventional analytical methods. In this work, a theoretical and deep learning hybrid model for predicting the surface roughness of diamond-turned polycrystalline materials is proposed. The kinematic–dynamic roughness component in relation to the tool profile duplication effect, work material plastic side flow, relative vibration between the diamond tool and workpiece, etc, is theoretically calculated. The material-defect roughness component is modeled with a cascade forward neural network. In the neural network, the ratio of maximum undeformed chip thickness to cutting edge radius R TS, work material properties (misorientation angle θ g and grain size d g), and spindle rotation speed n s are configured as input variables. The material-defect roughness component is set as the output variable. To validate the developed model, polycrystalline copper with a gradient distribution of grains prepared by friction stir processing is machined with various processing parameters and different diamond tools. Compared with the previously developed model, obvious improvement in the prediction accuracy is observed with this hybrid prediction model. Based on this model, the influences of different factors on the surface roughness of polycrystalline materials are discussed. The influencing mechanism of the misorientation angle and grain size is quantitatively analyzed. Two fracture modes, including transcrystalline and intercrystalline fractures at different R TS values, are observed. Meanwhile, optimal processing parameters are obtained with a simulated annealing algorithm. Cutting experiments are performed with the optimal parameters, and a flat surface finish with Sa 1.314 nm is finally achieved. The developed model and corresponding new findings in this work are beneficial for accurately predicting the surface roughness of polycrystalline materials and understanding the impacting mechanism of material defects in diamond turning.

Development of WE43/TiC surface composites using friction stir processing: a parametric study

Surface composites of WE43 Mg alloy reinforced with TiC nanoparticles were successfully fabricated using friction stir processing. The effects of various tool profiles, tool rotation, and transverse speeds on the metallurgical and mechanical properties of as-received and WE43/TiC composites were comprehensively investigated. The dispersion of TiC nanoparticles was uniform throughout the stir zone. The square tool at 1700 rev min−1 rotational speed and 60 mm min−1 transverse speed produced the finest grain structure in the composites, exhibiting maximum microhardness (151.7 Hv), maximum nano-hardness (1.596 GPa), maximum elastic moduli (36.54 GPa), and minimum wear rate (0.0279 mm3 min−1). Conversely, a square tool at 800 rev min−1 and 60 mm min−1 transverse speed produced the best mechanical properties in the WE43 alloy.

The Profiling of Hob Mill Used for Generating a Cycloidal Reducer’s Disk

This paper presents the profiling of the hob mill designed to generate the active surface of the cam of a cycloidal reducer. The algorithm allows determining the active surface of the generating rack gear, which is reciprocally enveloping with the active surface of the cycloidal disk. The novelty of the algorithm, based on the determination of the intermediate surface, consists in the fact that an innovative method of determining this surface is used, called the “virtual pole” method. The method allows determining the enwrapping curve of an ordered curl of surfaces, generated in the rolling movement of two conjugated centrodes. Using the “virtual pole” method, the calculation time for tool profiling is significantly reduced and the disadvantage of the resulting error, small enough to be neglected from a technical point of view, is fully compensated by this reduction in calculation time.

Effect of tool profile on wear and mechanical behaviors of CeO2 and ZrO2-reinforced hybrid magnesium matrix composite developed via FSP technique

A dual/double eccentric-pin tool was used for the reinforcement of the CeO2 and ZrO2 particles into a 5 mm thick AZ31B magnesium alloy through the application of the friction stir processing route to develop a composite with improved properties. A comparison of the developed composite's properties with that of the single pin-processed counterpart was carried out to ascertain the improvement recorded. The structure, hardness, shear punching strength, tensile, corrosion, and wear properties of the hybrid AZ31B/(ZrO2 + CeO2)p composite were investigated. The findings show that the dual/double eccentric pin tool widened the stir zone at the shoulder area, eliminated flow-related voids, and improved the flow of material and the particle distributions within the composite. The extra pin-induced plastic shearing/straining and dynamic recrystallization of the tool meaningfully refined the grain structure (5.6–3.35 μm) and the particle size (6.4–4.8 μm) of the composite while aiding even dislocation spread across the stir zone. In relation to the singular probe tool, the dual/double eccentric-pin tool also enhanced the hardness (102–141 HV), the shear punching strength (148–219 MPa), the tensile strength (175–225 MPa), the wear properties (coefficient of friction, rate, and loss), and the corrosion behavior of the hybrid AZ31B/(ZrO2 + CeO2)p composite due to the uniform and fine particle dispersion-strengthening and the elimination of stress raiser. The dual/double eccentric pin tool is thus recommended as a better tool for improving the performances of Mg-based composites.

Process parameter analysis of double pass friction stir composite welds

ABSTRACTThe novelty of the research work stems from the investigation of double pass FSW-friction stir welding on 6061 T6 and 7075 T651 alloys of aluminum matrix reinforced/supplemented with nano h-BN. Preparation of weldments was accomplished by deploying a range of welding parameters specifically tool spindle speed, tool traverse feed, and tool profile. L20 orthogonal array based on a CCD-Central composite design was implemented for experimentation. Microstructural and grain analysis with the performance of parameters on strength and hardness property was detailed. Regression models were developed and optimized based on RSM-Response surface methodology and GRA-Grey relational analysis. The optimal conditions favoring improved tensile strength and hardness based on RSM were realized at 848 rpm, 36 mm min−1, and with a tool profile being cylindrical. A state of consistency prevails between the predicted and experimental responses. Analysis based on GRA yields optimal conditions that fairly corroborate with RSM.

Improving the wear resistance and mechanical properties of hybridized AZ80 Mg/CeO2+ZrO2 surface composite by friction stir processing: Effect of pin geometry

Geometrically modified pins were utilized for the development of the hybrid AZ80 Mg/CeO2+ZrO2 composite by using the friction stir processing method. The local shear punching strength, structure, hardness, and wear of the hybrid AZ80 Mg/CeO2+ZrO2 composite were investigated. A change of the tool profile from cylindrical to conical pin profile eliminates particle clusters and inherent voids while the nugget shape, vortex width, and surface flash are also affected due to the tool's volumetric difference. Microstructural changes (grain and particle sizes) are also positively improved by the tapered pin tool, and these have about 24% improvement on the local shear strength of the composite while the hardness and the wear performances of the composite are also improved.

Experimental study of joining copper plate by using various process parameters and geometry pin profile

Friction Stir Welding (FSW) has become a feasible manufacturing alternative in the automotive and refrigeration industry to obtain the sound joining process. In many applications, steels are replaced by copper due to their excellent mechanical properties and corrosion resistance. Generally selection of material and design is affecting the overall performance of the sound weld. In this experiment, the joining of similar copper material is done by a friction stir welding process. The result shows that spindle speed, welding speed, tool geometry and its pin profile has influenced the mechanical properties of copper welded samples. Optimum defect-free weld is obtained at the range of spindle speed 1400 rpm, welding speed 45 mm/min with hexagonal tool profile.

Optimization of Friction Stir Welding Parameters of AA5052-H32 Aluminium Alloy using Taguchi and Taguchi-Pareto Methods

It is difficult to improve the quality of friction stir welded joints of AA5052-H32 material because of scarce metrics on its concurrent optimization and prioritization. However, the objective of this article is to obtain optimal parametric values and identify important parameters using the Taguchi-Pareto method during the friction stir welding process of AA5052-H32 material. Then the ranks, delta values and optimal parameters are determined. The critical parameters identified for the friction stir welding process are the tool pin, rotational speed, welding speed and tool angle. When comparing the results of these parameters using the Taguchi method and Taguchi-Pareto method, the rotational speed retained its first position in both methods; the tool tilt angle gained the second position in the Taguchi-Pareto method from its third position when only the Taguchi method was considered. The welding speed became the third position in the Taguchi-Pareto method against the second position that it had in the Taguchi method. However, the tool pin profile retained its last position in both methods. Consequently, the rotational speed is the best parameter while the tool pin profile is the worst parameter. For the Taguchi-Pareto method, the optimal parametric setting is TPP2/TPP4RS1WS4TTA3. This is interpreted as cylindrical tapered or square tapered for the tool profile, 40 rpm of rotational speed, 75 mm/min of welding speed and 1.5° of tool tilt angle. The novelty of this study is the scope of analysis of the AA5052-H32 material that extends beyond the Taguchi method to the Taguchi-Pareto method where the concurrent optimization and prioritization of friction welding parameters are achieved.

Design of a novel fixed abrasive petal-shaped lapping tool and material removal uniformity experiments on K9 glass

A novel fixed abrasive petal-shaped lapping tool is proposed to achieve the material removal uniformity based on finite element method (FEM) and mathematical analysis. The cross-sectional profile of the petal-shaped lapping tool is revealed according to the numerical analysis based on the in-plane stress distribution of disk elastomer tools in contact with the workpiece, which is shown and analyzed for the first time. Then, the practical experiments are carried out on the K9 glass plane workpieces to study the characteristic of the surface quality evolution and the material removal uniformity. Results show that the increasing material removal amounts along the radius are all suppressed under different experimental conditions, where the coefficients of variations of the two experimental groups with the better results are as low as 0.077 and 0.085, respectively. Moreover, the surface roughness Sa and Ra along the radial direction after lapping reach as low as 142 nm and 30 nm for the optical glass, achieving a drastic improvement of 77.2 % and 88.8 %. Thus, the design strategy of lapping tool with special structure will explore a new path of fabricating more specific tools in the field of ultraprecision manufacturing.

Robot-mounted sensing and local calibration for high-accuracy manufacturing

Positional accuracy is critically important for application of industrial robots in fixtureless precision manufacturing; thus, this paper presents a method for simultaneously calibrating the kinematic parameters of robot and robot-mounted measurement devices. In the modeling step, the Modified Denavit–Hartenberg parameters are extended to include the world and tool frames within a minimal parameter set using a systematic approach. Closed-loop calibration is performed using the data collected in the local target workspace using the robot-mounted measurement device. The presented modeling and calibration methods are applied to a case study in which a machining task is performed using a DENSO VS-6556 W industrial robot equipped with a cutting tool, force sensor, and laser profile scanner. In the case study, local models are calibrated for the laser and tool frames using common 1-2-3 blocks as calibration artifacts . The robot/laser model is identified by scanning the artifacts with a robot-mounted laser scanner , and the robot/tool model is calibrated by touching the artifacts with a robot-mounted force sensor. In this application, the robot/laser model is used to scan and register a sheet metal workpiece, and the robot/tool model is used to plan a tool path to machine the periphery. Positional accuracy of the tool path was evaluated to be ± 0.15 mm within the target workspace, which shows significant improvement compared with the mean error of 0.8 mm achieved by global calibration of the robot/tool model. • Simultaneous calibration of robot and extrinsic parameters of robot-mounted sensors. • Closed-loop calibration without external measurement devices. • Local calibration to improve accuracy within target workspace. • Systematic approach to include world and tool/sensor frame in MDH parameter set. • Case study for high-accuracy robotic machining application.

Thermal Stress Analysis and Optimization of FSW Process on UHMWPE by Using Hexagonal Tool Profile

Abstract: The use of polymeric materials has grown widely in various sectors such as packaging, building, electronic, automotive, and aerospace industries. Particularly, Ultra-High Molecular Weight Polyethylene has wide engineering applications and is used in large quantities in automotive oil pans, gears, slides, cams, bearings, fluid reservoirs, and the sports industry. Friction Stir Welding (FSW) is a solid-state process in joining thermoplastic materials. In this investigation, FSW process must be applied to join a UHMWPE plate of 8 mm thickness with specially designed hexagonal tool pin profile. The aim of this study is to examine the effect of main friction stir welding (FSW) parameters on the quality of UHMWPE plate welds. FSW machine, using a tool with a stationary shoulder and no external heating system. The welding parameters studied were the tool rotational speed which varied between 1300 and 1500 (rpm); the traverse speed which varied between 15 and 25 (mm/min), and the axial force ranging from 8 to 10 (KN). Good quality welds are achieved without using external heating, when the tool rotational speed and axial force are above a certain threshold. For high rotational speed and axial force welds have poor material mixing at the retreating side and mild voids at the nugget, tensile strength also obtained very poor. The hardness angle distortion and bead geometry also evaluated. Taguchi design optimum parameters and ANNOVA were found.

Features of zirconium alloy tubes production in cold pilgering

In the manufacturing of shell zirconium alloy pipes for nuclear reactor the required alloy texture must be ensured for failure free operation. The analysis of factors influencing the possibility of using design for the production of zirconium alloy pipes as a way of forming the required textural characteristics of the product is given. The different methods for calculating of profile of rolling tool are analyzed.

Bio-based insulation materials and model predictive control of active cooling systems in machine tools

The adoption of biological principles and materials plays a decisive role in the conversion to sustainable production technologies. Measures for the biological transformation of a machine tool were implemented following the example of warm-blooded animal, which automatically control their core temperature and, depending on their habitat, possess an insulating layer of fat. In this work, thermal insulation measures were implemented on machine tools using renewable materials and their effects were evaluated.Insulation materials of petrochemical origin such as polystyrene (Styrofoam) were replaced by alternatives made of mycelium with comparable heat insulating properties. On the lower machine bed, a slowdown of the cooling rate was observed after application of insulation materials at external temperature drops. The insulation between the machine bed and the control cabinet was also found to reduce tool centre point (TCP) displacement. This cost-efficient measure reduces the error during the process and the effort required to correct the linear axes and to heat and cool the machine.To homogenize the temporal and spatial temperature profile of machine tools, a control system was developed to compensate for thermally induced errors by means of adaptive active cooling. Therefore, a model predictive control using an embedded artificial intelligence (AI) model to forecast the structural temperature development was implemented. Through a hybrid training database combining experimental and simulative data series, a both flexible and precise determination of the thermal system behaviour could be achieved. On a real production machine, the active cooling system is divided into five individually controllable and adjustable cooling circuits. This approach allows cooling the machine structure according to time and local demand to minimize thermally induced TCP displacement under variable operating conditions.This paper serves to define and evaluate possibilities and requirements for the integration of bio-based insulation materials and control algorithms for homoiothermic conditions in production machines.

Data mining approach for production order identification in load profiles of machine tools: A change-point and clustering based analysis

With growing awareness of sustainable manufacturing and rising energy costs, the monitoring of energy-related quantities in production is expanded. Measurements of the power consumption of production systems are used to identify energy efficiency potentials or to allocate energy use and associated costs. However, time series of the power consumption of machine tools contain more information. Load profiles of production systems enable drawing conclusions on the specific production order carried out. Time stamps for certain machining operations can be extracted and used to link the machine tool's power consumption to a specific production order. The linkage of this data can assist the order-specific allocation of energy use or associated emissions. This paper presents a data mining approach to gain information on the executed production orders from the load profiles of a machine tool. For this purpose, load profiles of a machine tool are pre-processed and segmented based on change points. Subsequently, the resulting sequences are clustered with respect to their similarity. These clusters contain segments of machining cycles in which the same workpieces were produced. By matching the cluster sizes with the known quantity of the executed orders, associated time series segments are selected and linked to the manufacturing order. The approach is implemented in a Python framework and carried out with data from milling and turning machining centers monitored in an industrial environment. Time stamps for machining cycles can be identified reliably. No training data is required for the recognition of recurring patterns at the load profile of a machine tool, but production orders need to be distinguishable at least by workpiece quantity, which was given with all tested real data.

High-precision and high-efficiency fabrication of blazed grating by ultrasonic-assisted ultraprecision planing

Blazed gratings are optical components typically employed in modern optical engineering. To realize high-precision and high-efficiency fabrication of blazed gratings on reliable materials, an ultrasonic-assisted ultraprecision planing (UAUP) method using a round-nose diamond tool under elliptical vibration mode is proposed in this paper. High-phosphorus electroless nickel-phosphorus plating was adopted as the grating blank. The generation mechanism of the blazed grating texture was studied, and the relationship between the processing parameters and blazed grating characteristic dimensions was established. Through a combination of simulation and experiment, the theoretical and experimental results of the morphologies and optical performances of the blazed gratings were systematically compared and analyzed. The results show that the blazed grating configuration is an envelope of the diamond tool profile under ultrasonic vibration; the UAUP method has an extremely high machining efficiency owing to the high vibration frequency; and the blazed gratings fabricated using smaller vibration amplitudes exhibit high machining quality, good shape consistency, and favorable optical performance, thus verifying the feasibility of the UAUP method. • An ultrasonic-assisted ultraprecision planing (UAUP) method is proposed. • The grating configuration is precisely controlled by the processing parameters. • The machining efficiency of blazed gratings is extremely improved. • The fabricated blazed gratings exhibit favorable optical performance.