Swivel Head Research Articles

Research on positioning accuracy of the swivel head of milling and turning complex machining center

Abstract This article focuses on the swivel head of a milling-turning complex machining center and establishes a geometric error model between the rotary axes based on the multi-body system theory and the homogeneous coordinate transformation method. The double ball bar (DBB) is used to identify the geometric errors of the machine tool swivel head position-independent by measuring circular trajectories. The impact of PIGEs on the measurement trajectory is simulated. The swivel head is rotated at four angles (B0°, B45°, B90°, B-15°), and the laser tracker is used to analyze and study the linear axis straightness, perpendicularity, and the center coordinates and plane errors of the swivel head movement along the XZ plane. A swivel head rotation accuracy test fixture is designed to correct the positioning accuracy of a swivel head with a 45° inclination of the rotation axis. The research results show that the fluctuation of the center plane degree of freedom of the swivel head moving along the XZ plane is small, and the maximum value is 0.0086mm. Under the 45° angle posture of the swivel head, both the center coordinate error value and the plane error value are the largest. The simulation results of the swivel head position error are fairly consistent with the center coordinate error of the swivel head plane movement. A backward tilt displacement of 0.01mm~0.015mm of the machine column during assembly can reduce the influence of the weight of the swivel head on the perpendicularity and straightness of the vertical reciprocating motion, and adding auxiliary support near the base of the swivel head zero position can reduce machine straightness error.

Reliability evaluation of the drive system of a CNC swivel head with Bayesian networks

Reliability evaluation of the drive system of a CNC swivel head with Bayesian networks

Behaviour of electric drive of roller-bit drilling rig swivel head with fuzzy control

The efficient consumption of electric power in mining is an important task in power consumption optimization. The use of high-performance drilling rigs requires special attention to the development of energy-saving electric drive for open-cut mining operations. The increase of the efficiency factor and energy performance of a drilling rig is achieved through controlling the electric drive which allows the specific resonance frequency and limiting the current and velocity amplitudes to be regulated. The main idea of the study lies in the application of fuzzy controllers in the systems of automatic control of processes and equipment modes in mining production. The use of fuzzy controllers is aimed at improving the characteristics of PI and PID controllers. The calculations and simulation of transients based on simulation models in the MatLab 7.11 Simulink software package allowed reliable analysis of modes of a swivel head electric drive operation to be carried out. In the course of simulating the transients of swivel head velocity varying with the use of a fuzzy controller, fuzzy variables including mismatch of rotation velocity, mismatch change speed, velocity setting voltage were justified. The analysis allowed for the term-sets of fuzzy variables and the membership functions for each term-set of fuzzy variable to be defined. The simulation results showed that the control time (response) of transients of the swivel head motor torque and current change when using the swivel head velocity control by a fuzzy controller with increasing load depending on the rock hardness decreased by a factor of 2. Implementation of a system of automatic control of swivel head velocity with the application of a fuzzy controller allows drilling rig vibration to be reduced and provided effective protection of the swivel head electric (motor) drive from overload, thus increasing reliability of the equipment, and increasing drilling productivity.

Simulation model for uncertainty estimation of measurements performed on five-axis measuring systems

Five-axis measuring systems (i.e. coordinate measuring machines equipped with articulated probe heads capable of continuous indexation or five-axis machine tools with inspection probe mounted on a tilt and swivel head) are becoming more and more popular, especially in industrial applications, since their usage speeds up the measurement process without significant loss in accuracy. Widespread adoption of these systems necessitates development of viable and easy-to-use measurement uncertainty estimation methods. This paper describes the experiments required for identification of errors of five-axis measuring systems based on usage of LasrTracer system and measurements of ring standard. It also expounds the methodology for implementation of virtual CMM-based simulation model for these systems giving the explanation on all input quantities used in the model along with detailed mathematical explanations on uncertainty propagation procedure. Eventually, it presents the validation methodology and the results of validation measurements performed in order to prove the correct functioning of developed model. Basing on these results, the main conclusion drawn in the paper is that presented virtual model should be regarded as working properly and producing metrologically correct values of measurement uncertainty for common metrological tasks known from GD&T framework.

Kinematic error compensation of a double swivel head in five-axis abrasive water jet machine tool

With the improvement of manufacturing technology, five-axis machine tools have solved most of the linear error problems. And the rotating kinematics error problems have come to the front. Rotation tool center point (RTCP) function is one of the most effective solutions. Based on the RTCP function, a double swivel cutting head used in abrasive water jet cutting machine has been selected and its kinematic errors have been investigated through a double ball bar (DBB). And further, a new error mapping method has been built to compensate the geometric error. To verify the effectiveness of the method, a series of experiments have been carried out. The results of the experiments showed that, by applying this method, the precision of the tool cutting path could be improved greatly.

Applying PCI in Combination Swivel Head Wrench

Taiwan’s traditional industries are subject to competition in the era of globalization and environmental change, the industry is facing economic pressure and shock, and now sustainable business can only continue to improve production efficiency and quality of technology, in order to stabilize the market, to obtain high occupancy. The use of process capability indices to monitor the quality of the ratchet wrench to find the key function of the dual-use ratchet wrench, the actual measurement data, The use of process capability Cpk index analysis, and draw Process Capability Analysis Chart model. Finally, this study explores the current situation of this case and proposes a lack of improvement and improvement methods to improve the overall quality and thereby enhance the overall industry.

Design and workspace analysis of a 3-degree-of-freedom parallel swivel head with large tilting capacity

Traditional parallel mechanisms are usually characterized by small tilting capability. To overcome this problem, a 3-degree-of-freedom parallel swivel head with large tilting capacity is proposed in this article. The proposed parallel swivel head, which is structurally developed from a conventional 3-PRS parallel mechanism, can achieve a large tilting capability by means of structural improvements. First, a modified spherical joint with a maximum tilting angle of ±120° is devised to diminish the physical restrictions on the orientation workspace. Second, a UPS typed leg is introduced for the sake of singularity elimination. The superiority of the proposed parallel swivel head is theoretically proved by investigations of singularity-free orientation workspace and then is experimentally validated using a prototype fabricated. The theoretical and experimental results illustrate that the proposed parallel swivel head has a large tilting capacity and thus can be used as swivel head for a hybrid machine tool which is designed to be capable of realizing both horizontal and vertical machining.

Toolpath Planning and Simulation for Cutting Test of Non-Orthogonal Five-Axis Machine Tool

Owing to NAS 979 describes a cutting test for five-axis machine center with a universal spindle, several conditions for C-type machine tool have not been defined yet. This paper proposes a cutting test for a non-orthogonal swivel head and a rotary table type five-axis machine tool (C type) to evaluate its performance. The workpiece consists of 10 machining features. These features include the multi-axis simultaneous machining patterns and the positioning machining patterns. The flat end mill cutters are applied in each machining feature. Cutter location data for the test piece was generated using a commercial CAD/CAM system (UG) and converted to five-axis NC code using a postprocessor created in UG Post Builder. This UG postprocessor is verified through the developed postprocessor utilizing the modified D-H notation. It is also verified using VERICUT® solid cutting simulation software demonstrated the veracity of the generated five-axis NC code. The machining test is applicable for a variety of five-axis machine tool configurations.

Design and Experimental Study of a 3-DOF Parallel Swivel Head

Traditional parallel mechanisms (PMs) are usually characterized by small tilting capability. To overcome this problem, a 3-DOF parallel swivel head (PSH) with large tilting capacity is proposed in this paper. The proposed PSH, which is structurally developed from a conventional 3-PRS parallel mechanism (PM), can achieve a large tilting capability by means of structural improvements. Firstly, a modified spherical joint with a maximum tilting angle of ±120o is devised to diminish the physical restrictions on the orientation workspace. Secondly, a UPS typed leg is introduced for the sake of singularity elimination. The superiority of the proposed PSH is theoretically proved by investigations of singularity-free orientation workspace and then is experimentally validated using a prototype fabricated. The theoretical and experimental results illustrate that the proposed PSH has a large tilting capacity and thus can be used as swivel head for a hybrid machine tool which is designed to be capable of realizing both horizontal and vertical machining.

Direct Interpolation of Tool Orientation in 5-Axis Milling

By circumference milling with 5-axis machine or machining center has quite the machining efficiency and the surface quality of the products been improved. But when inclined inside surface of cavity is circumference milled with the default linear interpolation of rotation angle algorithm, it results in a serious non-linear error, which takes on over cutting or under cutting, e.g. the inclined plane will be over milled by the machine with dual swivel-head machining center. In order to resolve this problem, the direct interpolation algorithm of tool orientation is developed after analyzing the algorithm of linear interpolation of rotation angles and its non-linear error is. The algorithm is reported and tested with the object of a machine with AB-axis swivel head. The testing results proved that it can resolve the problem of non-linear error.

비행시험을 통한 경비행기의 속도계 보정

This paper presents the flight test procedure and the results for the airspeed indicator calibration of a light airplane the name of ChangGong-91, which is the first type certified aircraft from Korean Ministry of Construction and Transportation, as a part of the flight test validation to get the certification. The flight tests for airspeed position error calibrations are conducted using tower fly by method in order to calibrate swivel head testboom which is attached to the right wing tip of the airplane. Also system to system method is applied in order to calibrate the airspeed indicator of the cockpit. The flight test is conducted at the basis of the 'Korean Airworthiness Standard' which is the regulation of Korean Ministry of Construction and Transportation. The airspeed error range for the testboom and the airspeed indicator are determined to <TEX>$-0.75{\sim}+0.75$</TEX> knot and to <TEX>$-4.0{\sim}+2.0$</TEX> knots, respectively. The calibration results are applied to ChangGong-91 Flight Operation Manual.

Analyses of the Influencing Factors of Rotating Impeller Degassing Process and Water Simulation Experiment

On the basis of similarity principle a water-simulative study of the process of rotating impeller degassing (RID) was executed by means of self-made purifying system. The influencing factors on the RID process were studied and laid a theoretical basis for the further development of this kind of technique. The shape of vortex originated in rotating of impeller and its adverse effect on degassing effectiveness were discussed. Meanwhile the influences of shape as well as position of bluff body on degassing efficiency were investigated. The impacts of parameters such as gas feed rate and rotational speed of on degassing efficiency were discussed. The result revealed that the structure and design parameters of impeller are the decisive factors of effectiveness of RID facilities, and the design of the swivel head ought to aim for increasing the additional turbulent shear stress on air bubble and improving the degassing condition.

A Portable Instrument for Measuring Apparent Directional Reflectance

A portable battery-powered spectroradiometer has been constructed for the measurement of the apparent directional reflectance of natural targets. A silicon detector that is tripod mounted and positioned to monitor a horizontally oriented reference panel determines the target irradiance. A second detector for measurement of target radiance is mounted on the tripod swivel head. Electronic switching provides alter-nate detector references for the determination of apparent directional reflectance. Snap-on interference filters allow measurement in desired spectral bands. Equipment calibration procedures are discussed and typical experimental radiation data are given.