Automatic Polishing Research Articles

Processing Parameters Optimization and Experiment Research of Automatic Polishing Technology for Free Surface of Dies

Abstract: A kind of automatic polishing equipment for free surface of dies is designed, which is fixed on the backbone of numerical control machine. Processing parameters optimization are gotten by the orthogonal analysis method based on experiment data and surface roughness is about 1.0μm, which provides good basis of practical research and application of accurate working for free surface of dies.

A Method for Path Generation of Robot Automatic Polishing Based on Bounding Box

In order to solve the problem of high intensity and low efficiency by manual labor during the polishing machining of mold free-form surface, this paper present a method for path generation of robot automatic polishing based on bounding box. Firstly, ascertain the location and direction of the mold by constructing a box that is most close to the mold. Secondly, generate the tool path by introducing the improved direction-parallel machining. Finally, by using Visual C++6.0 development tool, the algorithm discussed above has been implemented and a software for trajectory generation has been developed. The results show that the method can generate the tool path better along the surface contour and is simple, effective. Besides, the software supplies a visible trajectory for robot polishing so that the unreasonable points can be modified before machining.

G130012 産業用ロボットを用いた研磨作業の自動化 : 統計的パターン認識に基づいた外観検査

This study deals with automation of polishing process by using an industrial robot. In polishing process, full automation of polishing operation has not been achieved due to the difficulty in visual inspection. Judgment of whether polishing is sufficient or not has been performed by skilled workers. In this study, the polishing after milling process is targeted. In the previous report, the generation of robot program for polishing operation based on CAD data was already proposed. Focusing on the periodicity of cutter mark patterns on milling surface, we proposed an automatic judgment of polished surface quality based on the image processing which uses Discrete Fourier Transformation. In order to capture images of polished surface, a CCD camera was mounted at 6-axis controlled robot hand. However, the image processing method proposed in previous report could not judge the curved cutter mark patterns because the periodicity of those patterns is not uniform. The objective of this report is the development of automatic judgment method for non-periodic cutter mark patterns. We developed judgment method which uses pattern recognition as a mean to judge existence or not of cutter marks. As a result, the developed system allows the automatic polishing that includes the surface quality judgment.

Design of experiments to optimise automatic polishing on five-axis machine tool

Despite the large improvements in the field of high speed machining, manual polishing operations are still necessary to achieve high quality surfaces named mirror for mould and dies or prosthesis parts. This paper deals with the description of a new polishing method performed on a five-axis machine. This method is based on the use of an abrasive discs mounted on a flexible rotating tool describing trochoidal trajectories. Firstly, the influence of each polishing parameter on the surface roughness is highlighted on a conventional polishing machine currently used in material sciences. Based on this knowledge, a specific application concerning the polishing of a stainless medical prosthesis is detailed in order to get a mirror surface roughness which Ra is less than to 50 nm.

Design and Dynamic Analysis of Horn for Ultrasonic Polishing

Ultrasonic polishing is an effective method to solve the bottleneck of polishing the mold cavity in mold processing, and the performance of ultrasonic horn is of utmost importance for the ultrasonic machining. In this paper the horn applicable to automatic ultrasonic polishing equipment is designed based on horn design theory, as well modal analysis and harmonic response analysis of four types of horn are carried out using Finite Element Analysis technique, which provides the basis and reference for further theoretical research and actual processing

Flexible Polishing Machine with Dual Grinding Heads for Aeroengine Blade and Blisk

The blade and blisk manufacturing includes polishing process when the surface roughness and size requirement of profile are disqualified after milling process. This polishing process is mainly carried out manually by skilled workers or NC machines. However, the existing polishing technology always leads to surface quality instability and inconsistency because of the complex free-form surface of blade and blisk. Therefore, in this paper, based on the research of polishing requirements and methods of blade and blisk, an automatic 6-axis polishing machine was proposed in order to enhance surface quality. And then, a polishing mechanism was designed using flexible technique to make the polishing tool accommodate surface waviness which was produced in milling process. In addition, the working principle and control method of flexible polishing mechanism were studied. Finally, the polishing test results of blade and blisk showed that the profile error was about 0.06mm and the surface roughness was less than Ra0.4 after automatic polishing. Compared with the manual polishing process, the automatic polishing technology not only increased the polishing efficiency and quality stability, but also reduced labor intensity largely.

Modeling of a Polishing Tool to Simulate Material Removal

In plastic injection mould and prosthesis industries, `mirror-effect` polished surfaces are required for obtaining transparent parts or surfaces without scratches. Traditionally done manually, we have proposed to automate polishing on 5-axis machining centre using a passive elastomeric carrier. One of the main advantages of automatic polishing is the repeatability of the machine movements in order to achieve restricted form deviations. However, the material removal rate (MRR) during polishing depends on parameters such as contact pressure, relative velocity and tool wear. We have thus developed a model dedicated to our process to compute the effective MRR along the polishing tool path regarding the contact area and the contact pressure between the tool and the part

Compensating the distortions detected by interference monitoring of off-axis aspheric surfaces when null correctors are used

This paper describes a method of interference monitoring of off-axis aspheric surfaces using wave-front null correctors, as well as an algorithm and program for taking distortion into account when constructing topographic maps of off-axis aspheric surfaces shaped on automatic polishing–lapping machines with computer control.

Process-control program for a series of automated polishing–lapping optical machines with computer control

A specialized control program has been developed, intended for carrying out sessions in which the surfaces of optical items are shaped on automatic polishing–lapping machines with numerical program control based on the Aerotech A3200 controller. The program makes it possible to monitor various aspects of process sessions, to correctly respond to emergencies, and to resume execution after they are overcome.

Movement Control of Small Moving Robots for Large Curved Surfaces Polishing

A small polishing robot must be made to adapt the change of curvature and slope of the cutting curved surfaces when it moves on the large curved surface. This paper develops a small moving robot to move on the large curved surface and polish it which can adapt the change of curvature and slope of the cutting curved surfaces. It also establishes the kinematics model and the inverse kinematics for movement control of the robot. By analyzing the motion characteristics and the processing of automatic polishing, the paper develops the posture equation of the robot. Experiments shows the small moving robot is capable of adaptability in polishing curved surfaces.

Research on Force-position-posture Decoupling Control for NC Polishing of Aspheric Parts

In order to resolve the problem of force-position-posture coupling in automatic polishing systems and improve the polishing quality of aspheric part surface,a new decoupling control method for NC polishing based on magnetorheological torque servo(MRT) is proposed.Theoretical and experimental studies on the principle and model of this method are carried out.After a deep investigation into the coupling mechanism,the model of force-position-posture coupling is established based on Preston equation and Hertz theory,the principle of force-position-posture decoupling based on the MRT is introduced,the control models of polishing force and rotational speed of aspheric parts are deduced,and a corresponding experimental system is developed.Experiments are carried out,and mirror-like aspheric part surface with a roughness of Ra?0.030 μm as well as constant material removal rates are obtained.Research results show that the MRT-based decoupling method can effectively resolve the problem of force-position-posture coupling,and provides a new way to achieve NC polishing of aspheric parts with high quality and efficiency and low cost.

Parametric Optimal Design of Robot End-Effector Tool for Robot-Assisted Automatic Polishing System

In this paper the multi-objective optimization design of a preliminarily designed end-effector tool for robot-assisted automatic polishing system is presented. ADAMS and iSIGHT are integrated for the multi-objective optimization design, the overall procedure of which is shown in this paper. Design of Experiment is arranged before optimization. The global optimization methods provided by iSIGHT software- Exterior Penalty and Multi-Island Genetic are utilized to perform optimizing process. Simulation executed in ADAMS with model updating with optimized structural design parameters verifies the significance of the multi-objective optimization in improving the performance of preliminarily designed end-effector tool.

Automatic Polishing Technology on Free Surface by Grinding Center

Die and mold are constructed with various free surfaces. In the machining of die and mold, it takes a long time to finish the curved surface. In this study high accurate polishing technique by GC (grinding center) with elastic ball type wheel is developed. In polishing process it is very important to remove cusp height without decreasing machined form accuracy. It is available to use GC in free surface grinding and finishing of die and mold with elastic ball type wheel. In polishing process only cusp height is removed in order to keep form accuracy that is produced in cutting process with ball end mill. In order to know the polishing characteristics of elastic ball type wheel, basic experiments were conducted. The polishing parameters Sp. were obtained experimentally by changing the values of polishing process. Using polishing parameter, removal amount can be obtained and polished surface is possible to estimate.

Study on Compliant Control by Cutter Radius Compensating for Rotating Curved Surfaces Polishing on NC Lathes

. Lots of new automatic polishing methods and equipments have been developed to solve the problem of low efficiency and quality in the traditional handwork curved surfaces polishing. However, these methods and equipments are complex and difficult to be applied in the industrial production. This paper proposes a new technology of rotate surface compliant polishing based on NC lathe cutter radius compensation. An efficient and compact rotate surfaces compliant polishing system is developed, which consists of a NC lathe, flexible polishing tool, workpiece, fixture and also the automatic programming software MASTERCAM. The polishing tool-path and NC code can be created in MASTERCAM. The value of the cutter radius compensation can also be set in NC code, so that the rotated surfaces can be polished by a traditional NC lathe. Experiment of polishing the aluminum sphere workpiece is taken, and the satisfying surface quality is achieved.

Large-area electron beam irradiation for surface polishing of cast titanium

Cast titanium is a known hard-to-polish material, and its final polishing step is a perpetual challenge. The best way to tackle this challenge lies in automatic and non-mechanical polishing methods. Against this background, the suitability of large-area electron beam (EB) irradiation was examined in this study. In parallel, the optimum condition for efficient surface polishing was investigated. Cast titanium specimens were prepared, whereby their surface glossiness, surface roughness, and corrosion resistance were measured before and after EB irradiation. After EB irradiation, favorable results were observed: the cast titanium surface became smooth, the glossiness increased, and corrosion resistance was enhanced. These results were attributed to the low heat conductivity of titanium. With mechanical polishing, this property results in temperature rise and burnout reaction of the titanium surface with oxygen and the abrasives. However, during EB irradiation, the low heat conductivity of titanium was an advantage in raising the surface temperature to the melting point, such that a smooth surface was yielded after solidification. Based on the results obtained, automatic polishing by EB seemed to be a suitable polishing method for metal frameworks of removable dentures, and an efficient one too by saving time and effort.

Automatic polishing process of plastic injection molds on a 5-axis milling center

The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute 5-axis cutter locations on free-form cavities in order to imitate the skills of the workers. These are based on both filling curves and trochoidal curves. The polishing force is ensured by the compliance of the passive tool itself and set-up by calibration between displacement and force based on a force sensor. The compliance of the tool helps to avoid kinematical error effects on the part during 5-axis tool movements. The effectiveness of the method in terms of the surface roughness quality and the simplicity of implementation is shown through experiments on a 5-axis machining center with a rotary and tilt table.

Recent Advances in Polishing of Advanced Materials

This article discusses the recent advances in polishing of advanced materials. Ninety-five journal articles published in 2005–2007 are briefly introduced. The topics are advances in chemical mechanical polishing (CMP), fluids for polishing, modeling of polishing, polishing of brittle materials, robotic polishing, polishing with vibrations or beams, and friction in polishing processes. CMP is perhaps the hottest research topic in the articles reviewed. Many “noncontact” processes are developed using magnetic fluids, electrorheological fluids, and abrasive flow for polishing of complicated geometries or difficult-to-approach regions. Modeling of polishing processes helps to understand the polishing mechanisms and is thus increasingly performed worldwide. More research on simulations of polishing processes can be expected in the near future. Polishing of brittle materials is also highly demanded. Automatic polishing of curved surfaces using robots and CNC machines, and polishing with vibrations and beams are promising. Investigations of friction in polishing processes help to understand the polishing mechanisms or control the polishing processes.

Fractal Tool-Path Planning for Free-Form Surface Polishing System

This paper presents a reasonable method for generating the tool-path of free-form surface polishing using the fractal curves. Free-form surface polishing processes as a finishing process are used to reduce the roughness of surfaces and smooth the surface form by eliminating the surface waviness left by tool marks, EDM spark erosion and so on. In the interest of realizing this aim without introducing undesirable surface waviness and time efficiency, a tool-path should provide even coverage of free-form surface during polishing. A fractal curve is suitable to cover the free-form surface uniformly at any complexity due to its plane-filling and self-similar characteristics. A method of generating the fractal path for free-form surface polishing is presented, and also an automatic polishing system is installed to confirm the path planning method’s validity.

Study on Building and Simulation of the Polishing Path of Mold Based on MasterCAM

In order to improve the surface quality and machining efficiency for mold polishing. Digital automatic Polishing is a good method, MasterCAM is the software that often is used for CAM machining, path layout and building method are emphasized according to the MasterCam’s curved surface processing path setting method, and aimed at the different curved surface use different polishing path building method, at last, the rationality of the polishing path building was validated.

New polishing technology of free form surface by GC

Abstract Polishing is an important finishing process in die and mold manufacturing. It is very popular to do hand polishing for free form surface although it takes long time and a lot of labor. From this point of view, many trials have been conducted in order to decrease polishing process or to develop the automatic polishing technology, which keep the form accuracy generated in cutting process. Recently grinding center (GC) which has the same ability of cutting as a MC (machining center) has been developed. In this paper a new polishing technology on free form surface with GC is presented. This new polishing technology applies the same CL used in cutting process to remove only cusp height effectively keeping the form accuracy generated in cutting process.