Complicated Workpiece Research Articles

A Three-Dimensional Structured Light Vision System by Using a Combination of Single-Line and Three-Line Lasers

A multi-line structured light measurement method that combines a single-line and a three-line laser, in which precision sliding rails and displacement measurement equipment are not required, is proposed in this paper. During the measurement, the single-line structured light projects onto the surface of an object and the three-line structured light remains fixed. The single-line laser is moved and intersects with the three-line laser to form three intersection points. The single-line light plane can be solved using the camera coordinates of three intersection points, thus completing the real-time calibration of the scanned light plane. The single-line laser can be scanned at any angle to determine the overall complete three-dimensional (3D) shape of the object during the process. Experimental results show that this method overcomes the difficulty of obtaining information about certain angles and locations and can effectively recover the 3D shape of the object. The measurement system's repetition error is under 0.16 mm, which is sufficient to measure the 3D shapes of complicated workpieces.

Numerical simulation of slab deformation process with different reduction values in vertical rolls of mill 2000 roughing stands

Perfection of rolled stock production processes at continuous wide-strip hot rolling mill (CWHRM) aimed at minimization of metal consumption, is an effective mean to decrease its cost. In the process of slabs rolling at CWHRM, the metal consumption is stipulated first of all by complicated workpiece forming in roughing stands during consecutive reduction by vertical and horizontal rolls. Results of the numerical study of slab deformation with different values of reduction in vertical rolls of roughing stands of mill 2000 are presented. The implementation of rolling process model based on application of DEFORM-3D program of finiteelement analysis described for evaluation of metal shifting from the edges of slab in the direction of the middle of the width. The convergence of the simulation results with the measurements data of workpiece forming during roughing rolling at Severstal mill 2000 was experimentally confirmed. It was found that an increase of reduction in vertical rolls has no significant effect on the metal shifting from a narrow edge to a wide one. Increase the total reduction in vertical rolls leads to an unfavorable stress-strain state of the edge region and the Cockcroft–Latham criterion rises by 20–30%. It was proposed to reduce the total reduction in the vertical rolls of the roughing stands of mill 2000 down to 40–50 mm. It was shown that increase of time of slab moving from the heating furnace to the scale breaker causes growth the Cockcroft-Latham criterion and does not affect the amount of metal shifting from a narrow face to a wide one. The proposed method of simulation the process of slab deformation in the roughing group of the mill 2000 proved by results of industrial rolling can to be used for further study of the effect of rolls profiling and forming of surface defects with the provision of minimal metal shifting onto a wide face.

A technique of experiment aided virtual prototyping to obtain the best spindle speed during face milling of large-size structures

The paper presents an original method concerning vibration suppression problem during milling of large-size and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model, called a modal approach, consists in identifying the parameters of the workpiece model created using the Finite Element Method (FEM). Thanks to the results of the identification of the modal subsystem obtained by the Experimental Modal Analysis (EMA) method, it can be stated that the parameters obtained from the experiment and delivered from the computational model have been correctly determined and constitute reliable process data for the simulation tests. The Root Mean Square (RMS) values of time domain displacements are evaluated. The efficiency of the proposed approach is evidenced by chosen technique of mechatronic design, called Experiment Aided Virtual Prototyping (EAVP). The proposed method is verified on the basis of the results of the experimental research of the relevant milling process.

Finite Element Analysis and Parameter Influence of Non-developable Ruled Surface Impeller Blade in Flank Milling

Through the cutting simulation of titanium alloy impeller blade, the effect of the actual milling processing path on the elastic part deflection to of complicated thin-walled workpiece with low rigidity and high precision is studied. Use the principle of impeller modeling to model the spline of the impeller, and the spline curve of the impeller generated in MABLEB is imported into UG for digital modeling. The spline curve is used to generate the neutral surface, and the suction surface and pressure surface are obtained by the method of non-equidistant offset. The model of the non-stretchable straight surface blade is imported into ABAQUS for static simulation. Using MATLAB to fit the experimental data in the reference literature that fits the milling process range, the side milling experience formula is fitted. Calculate the equivalent milling force corresponding to different axial cutting depths, import into ABAQUS and use Python for secondary development. By simulating the milling process through the life-and-death element method, the local elastic deformation law of the milled thin-walled parts when multi-layer milling the impeller blades is explored. The influence of different machining paths on the deformation of the tool is studied. Simulation results show that the part deflection of workpiece can be reduced by rationally planning the machining path.

Design of a Machine-integrated Optical Measuring System for Electrode Positioning for Electro-Thermal Precision Ablation

Besides traditional machining processes, unconventional machining by EDM (Electrical Discharge Machining) is used, especially when precise cavities with complicated shapes are required or hard to machine alloys need to be machined. For the production of a geometrically complicated workpiece, numerous differently shaped electrodes are required due to the variety of the single cavities and the tool wear. Due to the process-related tool wear, the electrodes can only be reused a few times. Thus, process chains consisting of milling electrode production, automated electrode changing and CNC-controlled erosion process are frequently used. After fabrication of the milling electrode, the electrode geometry is measured for quality control usually using a tactile measuring device. In order to assist in the orientation of the electrode in the EDM system, the consideration of measurement results with respect to a reference point would be helpful. However, the transfer of the measured coordinate parameters from the measurement system to the EDM system is not possible in most cases since there is no connection between the measurement system and the EDM system. In addition, the tactile electrode measurement is time consuming. With the help of a machine-integrated optical measuring system, it will be possible to save time for measuring the electrodes by automated optical measurements and thus replacing the tactile measuring method. The present study describes the technological development of a machine-integrated optical measuring system, which enables a qualitative optimization of the process chain from the production of the EDM electrode and the subsequent erosion process. The design of an optical measuring system consisting of CCD (Charge Coupled Device) sensors and a custom software for the evaluation of the results of the optical measurements are presented. The presented solution will prospectively be implemented into an industrial EDM-machine with the aim to achieve a more efficient process chain and to avoid incorrect machining.

Effect of the multiphase layer produced on surface of ZL205A aluminum alloy thin-wall barrel on quenching deformation

Aluminum-Copper alloys are widely utilized in military, aerospace and aircraft industries for its light weight, excellent castability, superior corrosion resistance, as well as high specific strength after solution, quenching and age hardening treatments. However, the distortion occurring in the quenching process limits its application, especially for the large scale complicated workpieces. In this study, a novel duplex treatment combining the coating and nitriding is applied to the sections of the thin-wall barrel that easy to deform during quenching. The results show that a gradient multiphase layer, consisting of two different regions, is shaped on the thin-wall sections easy to deform. The phase compositions of the surface and subsurface layer are dominated by TiN0.3 and Al3Ti, respectively. The Young's modulus of the TiN0.3 and Al3Ti are 199 GPa and 196 GPa respectively. While, the microhardness for both the two phases are 6.19 GPa and 4.24 GPa respectively, which are much higher than that for the aged ZL205A alloy substrate. The finite element method (FEM) simulation results show that the maximum temperature difference, thermal stress, residual stress as well as deformation of the thin-wall barrel workpiece are reduced due to the multiphase layer. Consequently, the maximum radial deformation of the workpiece can be reduced 96% due to the superior strength and hardness as well as heat conduction of the gradient multiphase layer.

A Study on High Efficient Machining of Complicated Workpiece Shapes on a Multi-functional Machine Tool

A Study on High Efficient Machining of Complicated Workpiece Shapes on a Multi-functional Machine Tool

Complicated workpiece shape machining using optimal target shape position and orientation on a multifunctional machine tool

Complicated workpiece shape machining using optimal target shape position and orientation on a multifunctional machine tool

A modification of DMVs based state space model of variation propagation for multistage machining processes

PurposeComplicated workpiece, such as an engine block, has special rough locating datum features (i.e. six independent datum features) due to its complex structure. This locating datum error cannot be handled by current variation propagation model based on differential motion vectors. To extend variation prediction fields, this paper aims to solve the unaddressed variation sources to modify current model for multistage machining processes.Design/methodology/approachTo overcome the limitation of current variation propagation model based on differential motion vectors caused by the unaddressed variation sources, this paper will extend the current model by handling the unaddressed datum-induced variation and its corresponding fixture variation.FindingsThe measurement results of the rear face with respect to the rough datum W and the pan face with respect to the hole Q by coordinate measuring machine (CMM) are −0.006 mm and 0.031 mm. The variation results for rear face and pan face predicted by the modified model are −0.009 mm and 0.025 mm, respectively. The discrepancy of model prediction and measurement is very small.Originality/valueThis paper modifies the variation propagation model based on differential motion vectors by solving the unaddressed variation sources, which can extend the variation prediction fields for some complicated workpiece and is useful in the future work for many fields, such as process monitoring, fault diagnosis, quality-assured setup planning and process-oriented tolerancing.

3D pose estimation of large and complicated workpieces based on binocular stereo vision.

A binocular stereo vision method is proposed for automatically locating the position and posture of workpieces, which is especially important when processing large, complicated structures, for example, the laser hardening and laser cladding of automotive die. First, a binocular stereo vision positioning system was designed and modeled, from which a method of background subtraction was proposed to extract the edge line of the foreground area. Furthermore, the intersection point of the workpiece contour line was taken as the characteristic point of the workpiece, and an algorithm that combines epipolar constraint with gray value similarity was proposed to quickly and accurately realize the feature points matching. Finally, experiments show that the workpiece can be positioned accurately, and that the precision of position recognition could be controlled within ±0.5 mm when the camera was 1m away from the workpiece, meeting the requirement of robot processing.

Modelling and simulation of nitriding process in SCM420 steel

In order to predict the nitrogen diffusion, phase transformation and hardness during nitriding process of the complicated steel workpiece. A coupled model that combines a multi-physical field theory with a finite element method (FEM) has been developed to simulate the nitriding process. It is considered the interaction among diffusion, transformation and temperature in multi-physical field model. A phenomenological model is presented to simulate the microstructural evolution of the nitride layer. The distribution of nitrogen concentration is calculated using a customised finite element program called computer simulation of manufacturing process (COSMAP). The model can predict nitrogen content, iron-nitrogen phase compositions and hardness. To validate the coupled model, the nitriding process of SCM420 cylinder and helical gear is simulated. It can be concluded that the present model can reflect the geometrical effect of the complex workpieces during the nitriding process. The simulated results are consistent reasonably with the available experimental results and the theoretical conclusions.

Research on Cu-Fe Solid Solution and Plastic Deformation Properties of Explosively Welded T2/DT4C Laminate

Explosive welding experiment of T2 red copper plate and DT4C electrical pure iron plate was carried out. Microcosmic analysis and plastic deformation test of the bonding interface were also studied. Results indicate that the welded zone presents periodical wavy metallurgical interface and Cu-Fe Solid solution is distributed on the wave interface. Moreover, large amplitude variation of the ratio of Cu to Fe in the Cu-Fe Solid solution is found. No separation happens after flattening test and bending test, which shows that Cu-Fe Solid solution does no harm to the bonding properties and the welding quality of T2/DT4C laminates can meet the needs of plastic working of complicated shape workpieces.

Study of the Floor Typed Abrasive Water Jet Spatial Machining Robot

A floor typed spatial robot of abrasive water jet machining is designed, which can be applied to machine three-dimensional complicated work-pieces. Its merits are simple structure and flexible moving. The structure and transmission programmer are discussed in detail. The working range of the abrasive water jet robot is analyzed to meet the need of the various sized work-pieces. The motion of the each joint is realized by means of various transmission programmers. The precise movement of the robot is realized by the stepping motor, and the required power of the robot is calculated.

Five-axis automated measurement by coordinate measuring machine

This research paper presents an analysis of the undercut interference and inclination interference caused by complicated 3D workpiece during measurement. The objective of this research is to propose a solution to the collision between measuring probe and workpiece for the purpose of automation and interference-free measurement. The fundamental procedure is based on the 3D CAD model of workpiece and five-axis coordinate measuring machine (CMM) measuring facility to generate an interference-free stylus orientation through three phases—adjustment of inclination angle under linear contour, adjustment of inclination angle under non-linear contour, and definition of rotation-free angle. Such manner not only solves the interference problems but also incorporates the minimization of counts of measuring probe rotation. In terms of methodology, the research adopts projection of cutting plane to determine the interference status of the measuring point, and based on the measuring inclination angle on the proposition of self-intersected contour and cross-intersected contour concepts, the range of safe rotation range can be determined by sweeping operation. Following the presented methods and procedures, the five-axis CMM simulation system for automated measurement is finally developed to validate the feasibility of proposed solution.

CAD/CAE System for Shaping Process of Three Dimensional Complicated Surfaces in Electrochemical Machining

The paper presented a computer aided design and engineering (CAD/CAE) system that can be used to simulate and analyse three-dimensional complicated workpiece’s shaping process in electrochemical mahining. In the CAE model the finite element method was applied to analysis the electric-field distribution in inter-electrode gap. Factors affecting the electric-field distribution, such as flow factors and passivating electrolyte, are also taken into account by using database technology. The results of simulation and experiments showed that the system was of high precision.

Development of CAM System for Multi-Tasking Machine Tools

Multi-tasking machine tools are very useful to manufacture complicated workpiece efficiently. However, it is very difficult to generate NC data when an operator uses multi-tasking machine tools. Currently, there are some CAM systems for multi-tasking machine tools. However, there are such problems as the manual allocation of parts to generate tool paths, the difficulty of self-interference recognition without a simulator, and so on. Therefore, this study deals with the development of CAM system which can recognize part configurations, calculate tool paths automatically for turning and milling operations, and sort them in machining order, based on 3-D CAD data of workpieces.

A3 Tool Path Generation for 5-Axis Control Milling Based on Area Division Method(Digital design and digital manufacturing(CAD/CAM))

The efficient machining of workpieces with a complicated shape has being increased in terms of realizing the products with compact design and sufficient functionality. 5-axis control machining is suitable to meet such a requirement since it can cope with machining these workpieces without removing them. At the time, it is very important to rapidly generate interference-free tool path. Thus, the study deals with 5-axis control tool path generation to machine such complicated workpieces on the basis of the area division method, where the interference area is divided into small areas. The validity of the method is demonstrated with simulated results.

Design on High-Speed Precision Grinder

As one of the modern manufacture technology, high-speed precision grinding takes an important part in the modern manufacture field. With the development of the technology on high-speed spindle unit, linear precision high-speed feed unit, manufacture of grinding wheel, measurement etc, a great deal of research achievements make it possible for high-speed precision grinding. In this paper, using PMAC (Programmable Multi-Axis Controller)—PC as the central controller, a new kind of high-speed precision grinder is designed and manufactured. The servo control technology of linear motor is investigated. The dynamic performances of the machine are analyzed according to the experimental results. Elliptical workpieces have been machined with this new high-speed precision grinder. Based on these research results, a very helpful approach is provided for the precision grinding of complicated workpieces, and these results promote the development of high speed grinding too.

Fast Determination Method of Tool Posture for 5-Axis Control Machining Using Graphics Hardware

In continuous five axis control machining, determination of tool posture is important process in NC programming. Especially, in fabrication of complicated workpiece, detection and avoidance of collision between cutting tool and workpiece surface are difficult problem. In the conventional studies, planning method of tool posture known as 2D C-Space method has been proposed. In this method, range of machinable posture is described as domain on polar coordinates system. Because estimation of machinable domain on 2D C-Space requires vast amount of geometric calculation for each tool location, an efficient estimation method is required. In this paper, we mention about a new fast calculation method for machinable domain on 2D C-Space. The proposed method is based on simple assumption that the collision can be regard as intersection between line of view and offset surface. We propose a new idea of unique view field, which can change projective method from Cartesian coordinates system to polar coordinates system by one rendering process. Then, we develop a new drawing algorithm of the machinable domain using both the proposed view field and ability of the latest graphics hardware. From performance of the developed prototype system, it is confirmed that the proposed calculation method can attain extraordinary improvement in the estimation time.

A feature-based inspection planning system for coordinate measuring machines

A feature-based inspection planning system is proposed in this research to develop more efficient measuring methodology for a CMM for complicated workpieces having many primitive form features. The proposed strategy is composed of two stages; global inspection planning and local inspection planning stages. In the global inspection planning stage, the system generates an optimum inspection sequence of the features in a part. The sequence is determined by analyzing the feature information such as the nested relations and the possible probe approach directions of the features, and by forming feature groups. A series of heuristic rules are developed to accomplish it. In the local inspection planning stage, each feature is decomposed into its constituent geometric elements, and then the number of sampling points, the locations of the points and the optimum probing sequence are determined. Also, an effective collision avoidance methodology is proposed. After required simulation, the effectiveness of the proposed system is verified .