5-axis Machining Center Research Articles

Research on nxug10.0 impeller automatic programming and DMU50 five axis machining center

Taking nxug10.0 software as the platform and impeller as an example, this paper analyzes the structural characteristics and processing difficulties of impeller, reasonably formulates the NC processing scheme, and uses nxug10.0 impeller processing module to plan the tool path, generate the tool path file, and simulate the processing to verify the correctness of the tool path. The NC program of impeller is generated by special post processor and uploaded to DMU50 five axis NC machining center to complete the actual processing of impeller. Through the detection of impeller, the results show that the impeller fully meets the design and use requirements.

Evaluation of Additive Manufacturing Parts Machinability using Automated GMAW ER70S-6 with Nodular Cast Iron

Through additive manufacturing is possible to obtain products with few material waste, low production time and great flexibility in geometry. In recent years, the application of arc welding processes has been studied as additive manufacturing techniques for metals. When compared to laser welding processes, they have low equipment cost, high deposition rate, however a low surface quality. This work proposes to study the machinability of additive manufacturing parts using automated GMAW. The deposition was carried out using a robotic arm, using ER70S-6' wire with a substrate of nodular cast iron. Two deposition strategies were carried out, one alternating the passes directions and the other one depositing in the same direction. The machining process used was milling in a three axis machining center. The deposition strategy had an influence on the parts surface finish after machining, as well as on the tool life.

Dynamic model identification for CNC machine tool feed drives from in-process signals for virtual process planning

Virtual process planning offers advantages in terms of predicting servo and contouring errors ahead of time, and taking corrective action by modifying the program or CNC parameters. Successful application of virtual process planning requires accurate models that capture the dynamics of feed drives. Identification of such models is typically time consuming.This paper presents a pole search method used in conjunction with least squares (LS) projection technique for identifying virtual machine tool drives. Compared to earlier research published in rapid identification, and the generic system identification method (i.e., a two-stage instrumental variable method), the parameter convergence has been improved significantly. This is achieved by reducing the number of unknown variables solved during LS estimation from eight to four (corresponding to each candidate pole triplet), and by avoiding the use of noisy position measurements and their time derivatives in the LS matrix pseudo-inversion. As a result, virtual feed drive models can be constructed using only in-process gathered data, without interrupting a machine tool's production for dedicated identification tests. Effectiveness of the new method is demonstrated in simulations and experimental case studies on two different machine tools, a gear grinding machine, and a 5-axis machining center. With the new method, servo errors can be predicted during the process planning stage to within 1-2% of closeness of their actual (experimental) values.

Based on PowerMill and K2X8 Five Axis CNC Machine of Realization of Integral Impeller Machining

Based on the powermill2019 software platform, taking the integral shunt impeller as an example, this paper analyzes the overall structure characteristics and machining difficulties of the integral shunt impeller, reasonably formulates the NC machining process plan, and uses the powermill2019 impeller machining module to plan the tool path, so as to generate the tool path file, and verifies the correctness of the tool path by simulation machining. Through the special post processor of powermill2019 five axis machining center, the NC program of integral shunt impeller is generated and uploaded to k2x8 five axis CNCmachining center to complete the actual processing of integral shunt impeller. Through the inspection of impeller, the results show that the impeller fully meets the design and use requirements.

Simulation of multi-axis grinding considering runout based on envelope theory

As one of the most important methods for machining process with high accuracy, ultra-precision grinding is widely used in fields such as aerospace, automotive and mold, etc. Simultaneously, it is common that wheel and spindle axis do not coincide with each other due to wheel settings, machining errors and so on. This could result in the generation of wheel runout, which may reduce the machining surface’s quality. In this paper, combining this phenomenon, an analytic algorithm method for the multi-axis grinding process is introduced according to the envelope theory. After that, the accuracy of this method is verified. Two experiments are carried out on a 5-axis machining center. The artificial runout is set up and calculated utilizing the least square method. Finally, using the presented method, two examples with and without runout are introduced to illustrate the validation of the proposed model. The error due to the runout effect is also analyzed.

Novel methodology for the measurement and identification for quasi-static stiffness of five-axis machine tools

Stiffness is an important characteristic of production machinery, as it contributes to its ability to precisely maintain the pose between a tool center point with respect to a workpiece under load. For machine tools, it directly affects the geometric dimensions and surface properties of the parts, i.e. how closely the parts match their design drawings. This work presents a novel measurement procedure to measure and identify full translational stiffness matrices of 5-axis machining centers using quasi-static circular trajectories. The measurement procedure consists of inducing quasi-static loads, which vary in magnitude and direction, at the tool center point of the machine tool using the Loaded Double Ball Bar and measuring the displacement with three Linear Variable Differential Transformers while the spindle tracks the circular trajectories inscribed by the movement of the rotary axis. The work outlines and quantifies the main components of the uncertainty budget related to the measurement of the translational stiffness matrices. The measurement procedure is implemented in a case study on a 5-axis machining center. Finally, the manuscript concludes with a discussion on the utility value of the translational stiffness matrix for the design and operation of machine tools as well as the possibility to expand the measurement procedure to a calibration procedure for 5-axis machining centers to analyze the translational and rotational stiffness.

Improvement of Simultaneous 5-Axis Controlled Machining Accuracy by CL-Data Modification

As the motion accuracy of 5-axis machining centers directly influences the geometrical shape accuracy of the machined workpieces, accuracy enhancement of the 5-axis machining centers is strongly needed. To improve the shape accuracy during the machining by a 5-axis machine tool, a method that modifies the CL-data based on the motion trajectory errors normal to the machined surface at each command point has been proposed. In this study, the proposed method is applied to simultaneous 5-axis controlled machining to improve motion accuracy. A normal vector calculation method for the simultaneous 5-axis controlled motion is newly proposed, and the compensation method is applied to turbine blade machining by 5-axis controlled motion. Measurement tests of the cutting motion for blade shape machining by a ball-end mill were carried out with a different control mode of NC. The CL-data for the machining tool path was also modified based on the calculated trajectory of the tool center point. Experimental results reveal that the feed speed and machining accuracy significantly depend on the control mode of NC, and that the shape accuracy can be improved by applying the proposed compensation method without any decrease in motion speed.

A Novel 13-step Diagonal/Sequential Measurement Method for Error Measurement and Compensation of Linear Axis Machining Center

CNC machining center is the biggest breakthrough in manufacturing industry. In three axis machining center total 21 geometric errors exist. Different techniques are used to improve machining accuracy thereby different compensation techniques has developed with time. Direct and indirect measurement methods are used to measure errors in machining center. Aim of this study is to analyse13-step diagonal or 13-sequential method to measure the error values in machining center by using interferometer by taking measurements on 13 lines. Measurements on twelve lines are measured by 12- line method but thirteenth line is measured by using step diagonal method along a body diagonal of machining center by moving one axis at a time. Experiment is done on machining center in three ways (1) without giving compensation (2) with lead screw compensation and (3) with 13-step diagonal method compensation. Two verification experiments are conducted (a) by using interferometer and (b) by manufacturing a designed part on machining center. Later manufactured part is measured on CMM before and after giving compensation. It is expected that the accuracy of machining center may improve error considerably. Errors along body diagonal are measured by using direct measurement which is more accurate and can give better results.

Alternative to parallelism test method for 5-axis machining center

Alternative to parallelism test method for 5-axis machining center

Determination of the Pallet Quantity Using Simulation in the FMS for Aircraft Parts

This study deals with the case study on the pallet quantity determination problem for the flexible manufacturing system producing 32 different types of aircraft wing ribs which are major structures of an aircraft wings. A Korean company has constructed the WFMS (wing rib flexible manufacturing system) that is composed of several automated equipments such as the 5-axis machining centers, the RGV (rail guided vehicles)s, the AS/RS (automated storage and retrieval system), the loading/unloading stations, and so on. Pallets play a critical role in the WFMS to maintain high system utilization and continuous work flow between 5-axis machining machines and automated material handling devices. The discrete event simulation method is used to evaluate the performance of the WFMS under various pallet mix alternatives for wing rib manufacturing processes. Four performance measures including system utilization, throughput, lead-time and work in process inventory level are investigated to determine the best pallet mix alternative. The best pallet mix identified by the simulation study is adopted in setting up and operating a real Korean aircraft parts manufacturing shop. By comparing the real WFMS’s performances with those of the simulation study, we discussed the cause of performance difference observed and the necessity of developing the CPS (cyber physical system).

Calibration of ball-rolling rollers with continuously variable pitch

Presented is the state of ball rolling production, review of existing techniques for roll pass design ball-rolling today development. Possibilities of roll pass design with regard to the existing metal cutting equipment and variation of pitch parameters. The priority is set for the use of rolling rolls with a continuously varying pitch, in comparison with rolls with discretely varying pitch. Possibility of using 5-axis milling equipment for obtaining a given profile, with several variable values, is shown. Model is developed for calculating the roll pass design for rolls with a continuously varying pitch, the save constant amounts of metall of workpiece between the rolls in every moments. Pitch change functions for roll pass design of ball rolling with a constant and variable flange width are derived, using which it is possible to determine the theoretical pitch at any rolls rotation angle. Technique for constructing a 3-D model is developed, based use on obtained curve of the 2nd order, which is the basis helical surface with a continuously varying pitch. Production of profile on a 5-axis machining center, according to the the 3D models suggest. Roll pass design was used ob the experience practical, with production example ball with a diameter of 120 mm, which were calculated from the deduced function for rolls with a constant width of the flange. He was tested in the conditions of the newly introduced ball-rolling mill of JSC "EVRAZ-NTMK". After introduction of a new roll pass design, were resived technical results: the reduction in force rolling, in contrast at use operating rolls with discretely varying pitch, by 25–30%, obtaining ball sizes that are as close to nominal values GOST standard, decreased of defects, uniformity forge along entire length of the rolls forming-part obtaining.The analytical solutions presented in this article, in combination with industrial approbation, make it possible to use a new method roll pass design rolls of a ball rolling mill with a continuously changing pitch for educational and production purposes.

Influence of tool path strategies on friction and wear behavior of high-speed ball-end-milled hardened AISI D2 steel

This paper aims at exploring how tool path strategies influence the friction and wear behavior of high-speed ball-end-milled hardened AISI D2 steel. High-speed hard milling (HSHM) operations were conducted on a 5-axis machining center with three different tool path strategies. Dry sliding friction and wear tests of test samples versus GCr15 rings were performed utilizing a block-on-ring tester. Results showed that friction and wear behavior were closely associated with tool paths. Though the same cutting parameters were used, there is a numerical evidence on the difference in surface integrity for different tool path conditions. Low friction coefficient was obtained for surfaces with microgroove orientation perpendicular to sliding direction. Inclination extent of grain boundary can act as a wear resistance indicator. The subsurface softening degree is the most evident factor by which tool paths influence wear behavior. It determines the way of carbide spalling and the severity of plastic deformation and then the main wear mechanisms. This study indicates that the friction and wear performance of ball-end-milled surfaces suffering from known friction loads can be improved by appropriate selection of tool path strategies.

High precision manufacturing method of multi-thread worm wheel using 5 axis machining center

High precision manufacturing method of multi-thread worm wheel using 5 axis machining center

Error calibration of controlled rotary pairs in five-axis machining centers based on the mechanism model and kinematic invariants

The mechanism model of ball bar testing for a two-axis rotary table of 5-axis machining center is discussed, and a new ball bar method to measure the three-dimensional motions of the rotary pairs in multi-axis machining center is developed based on the mechanism model. Then, the fixed axes and moving axes of the rotary pairs are identified by using spherical image circle fitting and striction circle fitting, according to the kinematic invariants of nominal rotation and the measured motions. The structure errors and kinematic pair errors of the rotary pairs are defined and identified by using the fixed and moving axes, and the kinematic model of the two-axis rotary table is deduced with those errors. The simultaneous two-axis motions of the rotary table are measured to verify the proposed calibration method. The experimental results show good agreements with the predicted results calculated by the calibrated kinematic model. Furthermore, the accuracy of the simultaneous multi-axis motions of the machining center is improved when the identified errors are corrected.

6軸制御マシニングセンタを用いた彫金文様の再現

Various fine patterns by chasing were sculptured to a copper plate by a non-rotational cutting tool using a 5-axis machining center. The 6th axis control was installed for rotation control of the spindle in the machining center. In this paper, out of the chasing technique, a consideration result by a force cut method for the traditional “KEBORI” technique using the 6-axis machining center was reported.

Formation and Control Technology of Top Burr in Micro-Milling

Burr formed during micro-milling slot has the most direct effect on surface quality and dimension accuracy of work-piece. Compared with other positional burrs, top burrs having the biggest dimension make the subsequent de-burring operation more difficult. To analyze the effect of spindle speed, cutting depth , feeding per teeth and blade radius on top burr size, Al6061-T6, used as research object, was conducted on a 5-axis machining center with the single factor method. Effect regularities of the process parameters on burr dimension were preliminarily revealed, active control of burr dimension during micro milling operation could be possible on the basis of the experiment.

Comparison of 4-axis and 5-axis Simultaneous Machining of Complex Shaped Blade

It is known that in multi-axis simultaneous control machining of complicated shape parts, machining accuracy may decrease due to synchronous error of the drive axes, and machining time may be longer due to excessive acceleration. In this study, in the machining using 5-axis control machining centers, in order to investigate the difference in machining accuracy and machining time depending on the number of drive axes simultaneously controlled, 4-axis and 5-axis simultaneous machining of a complex shaped blade are compared as a case study. As a result, it is found that the machining accuracy is better in the 5-axis simultaneous machining, but the machining time is shorter in the 4-axis simultaneous machining.

Tool Orientation Optimization for Reduction of Vibration and Deformation in Ball-end Milling of Thin-walled Impeller Blades

Due to the flexibility of one-side-supported thin impeller blades, machining defects such as overcut or undercut frequently occur, especially at the front and rear edge connecting the suction surface and the pressure surface, where the thickness are even less than 0.2 millimeter. Vibration and deformation are great challenges for engineers and should be mitigated for better quality. To this end, in the paper a method of tool orientation determination for vibration and deformation reduction during ball-end milling of flexible impeller blades is proposed. In order to reduce vibration level, carefully at the front and rear edge, the direction of resultant cutting force is attempted to be adjusted in the plane in which the stiffness of blade is relatively high. Thus, the cutting force component in the direction of high flexibility is small enough. As a result of modeling, two parts are included, i.e. modeling of tool-workpiece engagement and cutting force in the ball-end finish milling, FEM modeling of structure deformation of flexible workpiece. Machining experiments on 5-axis machining center Mikron UCP 800 verify that the optimized tool orientation could be used for deformation and vibration reduction in milling of flexible parts.

Precission plunge milling for angled vertical walls, on three axis machining center

In this study the authors will construct a type of milling based on the plunge milling and raster milling toolpath strategy, only this time it is not going to be used for roughing but only for finishing vertical and angled surfaces of particular components of injection molds, with the help of a three axis vertical machining center. This particular toolpath strategy designed, with a commercial CAM program, for finishing the vertical and angled walls, offers a better surface roughness, and a better dimensional control (accuracy), both for the milling tool and also for the work piece.

Design and Research on the Special System for High Efficient Manufacturing of Blisk Based on UG

As one of the most important parts of aeroengine, blisk has complex structure and its material is titanium alloy hard to machine. It results in some difficulties in modeling and NC programming. In this paper, from the perspective of application, the secondary development technology of UG/Open Grip is used to design and develop the CAD/CAM module of blisk after analyzing structure feature and milling process of blisk. Firstly, it completes parametric modeling of blisk by establishing CAD module through the optimization of the original data points in NUBRS curve fitting and node interpolation technology; secondly, the inner and outer tolerance algorithm are applied to calculate the cutting step, and the row spacing is determined based on constant scallop height. Besides, tool axis vector is defined. All of these things are done to complete the establishment of the CAM module and realize trajectory planning of semi-finish machining of the blisk. It greatly improves the efficiency of programming and machining in blisks; finally, the module of blisk designed is used to model and program in the machining experiments in five axis machining center to verify correctness and reliability of the system. The results show that this module greatly improves manufacturing efficiency of blisk.