Automatic Tool Changer Research Articles

A study on the Design of Drum Type Automatic Tool Changer

A study on the Design of Drum Type Automatic Tool Changer

HydraX, a 3D printed robotic arm for Hybrid Manufacturing. Part I: Custom Design, Manufacturing and Assembly

This study aims at the parametric design, manufacturing and assembly of a low cost 6-axis 3D printed robotic arm, HydraX, which enables the combination of Additive and Subtractive Manufacturing processes on a single machine tool, through proper control and efficient movement programming. The robot was custom designed and manufactured by a domestic 3D printer with PETG, so as to serve both functional properties and aesthetics. 3D printing parameters were carefully chosen for adequate robot part stiffness and integrity. HydraX construction was complimented with proper off-the-shelf parts and motors for smooth operation. It has the ability to change its end-effector (milling spindle, 3D printing hot end, laser engraver, or gripper) via its specially designed Automatic Tool Change system, thus providing multiple manufacturing processes and part handling. HydraX has enough working volume to enable manufacturing of medium-size soft material parts and the stability to offer precision up to few tens of microns.

Surface Topography Measurement of Mirror-Finished Surfaces Using Fringe-Patterned Illumination

Mirror-finished surface products have a wide range of applications in different engineering industries, such as power generation, aerospace, semiconductors and optics. The surface topography of mirror-finished products is typically measured in a metrology laboratory, which is typically time consuming and cannot be integrated into the manufacturing process. To allow for in-situ product quality assurance and automatic tool change for manufacturing processes, a more accurate and responsive surface-measurement method is needed. For highly polished surfaces, a sub-micron surface fluctuation makes it possible to use light-scattering effects and image processing for surface texture analysis. A non-contact surface inspection system using a fringe-patterned illumination method is proposed in this paper. A predesigned pattern was projected onto the target surface, and its reflected image was captured by a camera. It was found that the surface parameters Sa and Sq, which are widely used to evaluate surface quality, are significantly correlated with luminous-intensity distribution. Another parameter, Str, which quantifies the uniformity of surface-texture directions due to polishing or grinding marks, was traditionally quantified after a complete-surface topographic measurement. In this research, a new approach is proposed to determine surface isotropy through a luminance-intensity distribution analysis. By rotating the test coupon, the variation of specular reflection showed correlation with the significance of surface-texture direction. The experimental results demonstrate that mirror-finished surfaces with a large deviation in luminance intensity across the pattern possess low Str values, which indicates low uniformity in surface texture.

Study on failure warning of tool magazine and automatic tool changer based on tool-pulling force

A tool magazine and automatic tool changer is used to store and change tools in a machining center. Its failures would increase the maintenance time and repair cost. For decreasing failures, an early warning system of failures can be used to detect characteristic signals which can reflect potential failures. The tool-pulling force is increasing to peak value instantly when the tool changing arm draws a tool holder out of a tool pocket. To predict failures, the tool-pulling force signals are analyzed and the relationship between the maximum tool-pulling force and the severity of the lock spring failure is established, then, calculation method of the tool-pulling force threshold of the lock spring failure which can lead to tool falling failures is developed and demonstrated. The verification testing results show that the failure warning method based on the tool-pulling force threshold is feasible to predict the tool falling failures.

Track-based analysis for profile generation on globoidal cam in automatic tool changer of CNC machining center

PurposeThis paper aims to propose an elementary approach towards the measurement of a globoidal cam profile used in an automatic tool changer (ATC) of computer numerical control (CNC) machines.Design/methodology/approachA simple and unique online method has been designed for the profile metrology of the cam. This simple methodology will replace the traditional methodology of profile metrology of cam by coordinate measuring machine (CMM). A globoidal cam with an indexable turret and roller follower (rotating in an enclosed track) has been evaluated in our analysis. This analysis plays a significant role in the performance determination of the cam as well as the ATC of CNC machines.FindingsA novel model has been designed and implemented to investigate the profile of a globoidal cam. The proposed methodology becomes an enhancement over the old methodology, i.e. measurement through CMM. Theoretical analysis and practical implementation prove the significance of the method.Originality/valueAn enhanced methodology to effectively measure the globoidal cam profile has been proposed. The practical implication of the proposed methodology remains for the CNC machine tool and ATC manufacturers. Finally, analytical explorations have been carried out to prove the validity of the proposal.

Research on TBF distribution model of circular tool magazine and ATC

Tool magazine and automatic tool changer (ATC) is one of the most important function units of a machining centre and its reliability directly influences the reliability of the machining centre. Failure analysis is the basic work in reliability study. So far, there are few studies on failure of the tool magazine and ATC. Based on the failure data obtained from the field tracing of a kind of circular tool magazine and ATC, the probability density function, the distribution function and failure function of time between failures (TBF) of the tool magazine and ATC are calculated. It is preliminarily assumed that the TBF of the circular tool magazine and ATC obey Weibull distribution. Parameter estimation and hypothesis testing of the Weibull distribution model are done. Finally, the effectiveness of the model is verified. The work can provide a reference for failure prediction of circular tool magazine and ATC.

Energy consumption analysis of automatic tool change processes

The automatic tool change system was used frequently in numerical control machining processes. Preliminary studies indicate that the power demand of an automatic tool change system is an important part of auxiliary units power demand for numerical control machining processes. Research to date on energy consumption modeling largely focuses on cutting processes while the power demand of automatic tool change processes is treated as a given constant. However, energy consumption modeling of automatic tool change processes is a method that has been overlooked in previous investigations. In fact, the tool change power demand and time vary depending on the turret motor rotation angle for changing tools. Thus, this study aims at solving the above problem by analyzing the power demands of different tool stations for changing tools. The energy consumption modeling method of an umbrella tool changer system was proposed to address the limitations of existing models and validated on a vertical milling machine. In this study, one tool change cycle was divided into five different power demand stages. This is different from the common method where the power demand of one tool change cycle is fixed. The milling case was investigated, and experimental results showed that the proposed modeling method can provide a reliable energy consumption prediction for tool change processes with high accuracy, which can assist manufacturers to develop potential energy saving strategies.

초정밀 대형 머시닝센터의 바닥 지반 설계에 관한 연구

With the advent of high-tech products, the need for ultra-precision machining has become increasingly necessary, along with the need for a jig center machining center capable of precision machining. A jig center maintains the accuracy of a jig borer, and also has an automatic tool changer like that of a machining center. It performs various machining functions in addition to hole machining and is the most precise and rigid machine tool. Various control methods and analytical techniques to improve machining accuracy are currently being developed in the field of ultra-precise large-scale machine tools. One relevant finding is that the degree of deformation varies depending on the weight of the machine tool as well as the ground conditions. It is therefore necessary to optimize ground conditions before installing the machine tools so as to improve the machining accuracy. The depth of concrete as well as the depth and diameter of grout were selected as variables. We developed the simulation case through structural analysis to consider the position of columns and tables. As a result of optimizing the foundation condition, it was found that the relative displacement error was reduced by up to 98% compared to the rigid foundation condition.

A new non-servo motor type automatic tool changing mechanism based on rotational transmission with dual four-bar linkages

In the non-servo motor type automatic tool changer (ATC), the rotational transmission mechanism (RTM), which converts the rotary motion with specific rotational ratio, is important. This paper presents a new design for RTM with dual four-bar linkages for the non-servo motor type ATC. This RTM is entirely different from the mechanism using single four-bar linkage, in which the motion is intermittent. In the case of the mechanism using single four-bar linkage, the shape of the trajectory of four-bar linkage is the only design consideration. However, in the case of the proposed mechanism, both the shape and the speed ratio of the contact and non-contact paths of the trajectory of the four-bar linkage have to be considered. Therefore, the four-bar linkages are designed using the new path synthesis algorithm based on the derivative of the target trajectory. Through various analyses, this paper provides the proper design of the RTM. A prototype of a machining center using the developed ATC with RTM was created to verify the feasibility and for kinematic experiments. The research shows that the new RTM with linkage mechanism is suitable for practical applications.

Development of a Structured Algorithm to Identify the Status of a Machine Tool to Improve Energy and Time Efficiencies

Energy efficiency is a matter of concern for manufacturing industries due to ever increasing energy costs and strict environmental policies. Efficient monitoring of energy consumption of machine tools is first step towards energy conservation. This study presents a non-intrusive energy monitoring technique to quantify the energy consumption of a machine tool at the unit process level and determines the operational status of the machine tool using the energy data profile. A combination of K-nearest neighbors and principal component analysis is used to develop smart energy sensor which can determine the time and energy spent during each operational state of the machine tools. It also identifies the operational state of various machine tool components such as spindle, coolant pump, automatic tool changer, etc. The time and energy map provided by the proposed sensor will help the practitioners to identify the potential areas of energy and time saving.

Four-bar linkage-based automatic tool changer: Dynamic modeling and torque optimization

An Automatic tool changer (ATC) is a device used in a tapping machine to reduce process time. This paper presents the optimization of a Peak torque reduction mechanism (PTRM) for an ATC. It is necessary to reduce the fatigue load and energy consumed, which is related to the peak torque. The PTRM uses a torsion spring to reduce the peak torque and was applied to a novel ATC mechanism, which was modeled using inverse dynamics. Optimization of the PTRM is required to minimize the peak torque. The design parameters are the initial angle and stiffness of the torsion spring, and the objective function is the peak torque of the input link. The torque was simulated, and the peak torque was decreased by 10 %. The energy consumed was reduced by the optimization.

Design and Control of Automatic Tool Changer for Machine Center

Automatic tool changer (ATC) device is an essential part in CNC Machining centers, which can make the machining centers smoothly running using the tool magazine and automatic tool changer control system. In order to reduce the non-cutting during work, improve productivity and reduce production costs, machinery part and control system of ATC are designed based on the disk tool magazine and tool change process of machinery arm. In this system, PLC is used as brain to magazine the tool moving, automatic tool selection, cutter spindle sleeve rollover and exchanging control. Results show that the designed automatic tool changer device and control system have the characteristic of stable performance, precise control, simple operation, and convenient monitoring. From the view of industrial applications, this system has well practical value.

Повышение точности обработки на станках за счет минимизации погрешностей инструментальных систем

The problems of accuracy increase at machining are considered, in particular: error minimization in a taper part of a tool-holder at automatic tool change, the development of recommendations on cone manufacturing quality.

The Development of an Interactive Automatic Tool Changer System Based on Virtual Reality Technology

Automatic tool changer system with high operability is the critical component of high efficiency automated machine tools. This paper introduces an interactive simulating platform for an automatic tool changer system based on virtual reality technology, with which students can know the structure of chain tool library, the principle of tool changing manipulator and the various cutting tools. In this paper the frame structure of the interactive simulating platform and the working principle of the platform were explained. The motion control mechanism of components of automatic tool changer system was elaborated in the way of taking the process of changing cutting tools as an example. The interactive simulating platform of the automatic tool changer system utilizes browserbased structure, Java3D, virtual, Java Applet and some other technologies to develop a Web3D virtual reality learning environment, with the advantages of easy understandability, good interactivity, strong sense of reality, simple updatability, small investments and so forth, which can satisfy the requirements of online learning for many students at the same time. It is very important in the distance online education or vocational skills remote training of mechanical engineering.

PRECISE ROTARY TABLE INDEXING SYSTEM USED ON MILLING MACHINING CENTRES

Growing performance demands in the mechanical manufacturing field have lead to a great development of the machine tools domain, regarding especially the productivity and the manufacturing precision. When equipping a machine tool with an automatic tool changer and an automatic pallet mechanism, the obtained result is a machining center. For small series products, milling machining centers fulfill the precision and productivity requirements, through the advantages of a reduced auxiliary time and reduced operating errors. This paper presents a new technical solution of the rotary table indexing mechanism used on milling machining centers, which offers a very high positioning precision, by using a curvic coupling and a hydraulically driven table clamp/unclamp mechanism.

Minimizing tool switching and indexing times with tool duplications in automatic machines

Minimization of nonmachining time is a crucial issue for effective and profitable utilization of automatic machining centers. Most of the automatic machining centers contain an automatic tool changer (ATC) for holding multiple cutting tools. Effective operation of ATC in relation to the parts assigned for machining is critical in minimizing nonmachining times. There are actually two main operations on ATCs which can be reduced by making use of suitable optimization procedures. These operations are known as “ATC indexing problem” and “tool switching problem (ToSP).” These problems are separately addressed as NP-hard problems in the literature and mostly solved independently so far. In the present work, we made an attempt to solve these problems simultaneously by making use of a simulated annealing (SA) algorithm with novel solution coding/encoding strategies. The results are compared with the lower bounds obtained by a method proposed in the present work. Promising findings are expected to contribute to the possible future work of this research field.

Cell design and multi-period machine loading in cellular reconfigurable manufacturing systems with alternative routing

This paper deals with the design and loading of Cellular Reconfigurable Manufacturing Systems in the presence of alternative routing and multiple time periods. These systems consist of multiple reconfigurable machining cells, each of which has Reconfigurable Machine Tools and Computer Numerical Control (CNC) machines. Each reconfigurable machine has a library of feasible auxiliary machine modules for achieving particular operational capabilities, while each CNC machine has an automatic tool changer and a tool magazine of a limited capacity. The proposed approach consists of two phases: the machine cell design phase which involves the grouping of machines into machine cells, and the cell loading phase that determines the routing mix and the tool and module allocation. In this paper, the cell design problem is modelled as an Integer Linear Programming formulation, considering the multiple process plans of each part type as if they were separate part types. Once the manufacturing cells are formed, a Mixed Integer Linear Programming model is developed for the cell loading problem, considering multi-period demands for the part types, and minimising transportation and holding costs while keeping the machine and cell utilisations in each period, and the system utilisation across periods, approximately balanced. An illustrative problem and experimental results are presented.

전방향 이동 메커니즘을 적용한 콘크리트 폴리싱 로봇의 성능평가

Article history: In the construction industry, concrete polishing is used to grind and rub the surface of concrete grounds with polishing machines to increase the strength of the concrete after deposition. Polishing is performed manually in spite of the generation of dust and the requirement of frequent replacements of the polishing pad. The concrete polishing robot developed in this research is a novel polishing automation system for preventing the workers from being exposed to poor working environments. This robot is able to change multiple polishing tools automatically; however, the workers can conveniently replace the worn-out polishing pads with new ones. The mobile platform of the polishing robot employs omnidirectional wheels to enable a flexible motion even in small and complicated workspaces. To evaluate the performance of the developed concrete polishing robot, extensive experiments including square trajectory tracking, automatic tool changing, actual polishing, and path generation simulation were performed.

Study on failure warning of tool magazine and automatic tool changer

Tool magazine and automatic tool changer (ATC) is used to store and change tools in a machining center, which plays an important role in automatic manufacturing. Therefore, the stability and reliability of tool magazine and ATC is very important to a machining center. Failures of tool magazine and ATC would increase ramp-up repair time and repair cost. So early warning system of failures for tool magazine and ATC becomes a research hotspot. The main vibration signals of tool magazine and ATC would occur obviously when the tool arm grasps a tool holder, draws a tool holder out of a tool into spindle or tool pocket and inserts a tool holder into spindle or tool pocket. To predict failures of tool magazine and ATC and improve the availability of machining center, a vibration test procedure and calculation method of vibration signal threshold of pull nails looseness which can lead to tool falling failures are proposed based on the vibration detection theory. Then, the vibration signals of tool changing are analyzed and the relationship between the maximum amplitude of vibration signals and the looseness severity of pull nails is also illustrated. The final experiment results show that the tool falling failure warning method is feasible to reduce the failures of tool magazine and ATC through the early warning system based on the threshold of vibration signals.

자동공구교환장치를 이용한 융합 FDM 공정 및 장치개발에 관한 연구

The purpose of this study is an attempt to improve the functionality of a conventional Fused Deposition Modeling (FDM) process using the Automatic Tool Changer (ATC) to perform multi-material production and post-processing. Hybrid-FDM means a fusion of an Additive Manufacturing process and grinding process using the ATC system. In order to enhance the potentiality of production capacity for multi-material fabrication and surface roughness improvement, two extrusion tools and one grinding tool system are suggested. A pneumatic chuck is attached on a moving platform in the XY axes plane and an extrusion head and grinding head are placed in a docking station, allowing for a quick changeover with each other. Therefore, the manufacturing lead time can be reduced efficiently for the fabrication of a product.