Papers by Keyword: CAM

Abstract: With the rapid development of smart manufacturing, traditional processing is gradually moving towards automation, and the mold industry is no exception. Facing the ever-changing and complex product demands, the requirements for efficiency and precision are also increasing. However, currently most of the parts process planning rely on experienced personnel. They will decide the machining sequence and schedule according to the manufacturing method for the parts, and then use Computer-aided Manufacturing (CAM) software to simulate the processing time. Manual operation not only requires a lot of human-resource costs but also increase the lead time required for manufacturing, and even because of those human errors, resulting in delays for delivery. On the other hand, the trend of processing automation makes the accuracy of processing time estimation more important. Therefore, this study develops a navigating system to shorten the processing lead time by simplifying the operation process and combine regression analysis to improve the accuracy of machining-time estimation. This study uses ASP.NET MVC Framework as the framework and applied Computer-aided Design (CAD) software, Siemens NX (also known as NX Unigraphics, or UG for short), to create a machining navigating system on its secondary development module for Wire Electrical Discharge Machining (WEDM), Electrical Discharge Machining (EDM). Moreover, it integrates the existing CNC milling machine machining navigating process. This study identifies the features of WEDM and EDM through automatic recognition, and then navigate the user to perform Numerical Control (NC) programming with automatic settings and simple parameter input, and finally generate NC Codes automatically. For the EDM, the system will automatically decide the processing range and generate electrode heads after the feature recognition is confirmed. The processing parameters will be stored in the Microsoft SQL Server Express database and sent to the linear regression analysis model. The actual machining time is used as the training label to optimize the parameters in order to improve the accuracy of the estimated working hours. The navigating system in this study can effectively shorten the processing simulation operation time by 84%, and at the same time a large amount of training data for regression analysis training can be generated. The maximum and average errors of machining time is reduced from 45%/32% to 23%/12%, which improves production efficiency and the accuracy of scheduling.

Abstract: Currently, there is no function in commercial CAM systems to generate optimal quality machining for curved surfaces. In computer-aided manufacturing (CAM) systems, the toolpath (cutter location data) is derived as an approximately straight-line segment based on a plane approximation surface instead of a free-form surface from the designed shape. Due to this approximation, machining accuracy and quality are decreased, especially in the region with characteristic lines like in an outer automobile covering part. This paper presents an algorithm procedure for toolpath generation to process complex parts with characteristic curves with high-quality and high-accuracy machining by dividing the surface into different regions, the region where machining accuracy is not required as a plane approximation surface and the remaining region where accuracy is required as free-form surfaces. The proposed method was confirmed by machining experiments that actual machining realized high machining quality and accuracy compared to the conventional CAM system.

Abstract: Brittle materials such as ceramics, glass or single-crystal silicon are extensively used for industrial applications and recently become an object of actual research due to the development of new products and technologies. In cases, where special attention is paid to the surface layer, mechanical processing with a diamond tool is of interest as one of the most efficient technology to manufacture products from brittle materials. In this paper, simulation method is presented, which allows to estimate an effect of cutting force on the size of defects zone formed in a hard brittle plate during machining. In the proposed model, there is a distinguished surface layer, which can have its own unique properties that differ from the properties of the brittle plate. In this work, the ANSYS finite element program is used to simulate the technological processes and solve the problem of stress distribution in a quasi-static formulation.

Abstract: Contour turning is a specific process of the machining on CNC lathes. In the finishing operation, to create the part profile, the turning tool must be moved in a trajectory of a complex flat curve (a toolpath) based on the part profile . The variation of feedrate vector on the toolpath according to the part profile in the machining process will results in changing dynamic geometric parameters of the cutting tool, which affects cutting conditions and machined part quality. This article presents the results of theoretical studies on the influence of part geometry on rake angle, clearance angle, approach angle and end cutting-edge angle of the turning tool. Based on the theoretical development, the authors also set up mathematical expressions that allow to define gouge-free cutting condition and the limit of feedtate for contour turning. An empirical model to define the influence of part geometry on the roughness of the part when countour turning on CNC lathe is also presented in this report.

Abstract: A systematic and detailed approach in design and manufacturing of blow molds for bottles made of PET and PP plastic material with CAD/CAM software tools is presented, as many production errors and product deficiencies stem from inaccurate and imprecise tooling. Apart from high mold accuracy, proper planning also includes the minimization of mold machining costs, which mainly derives from CNC machining time and cutting tool wear. Blow mold design and manufacturing revolves around two major axes: (a) mold material and (b) machining parameter values. The former is critical in terms of production rates and mold life-cycle and the latter has a great impact on mold manufacturing cost, as well as on quality of the produced plastic bottles. Proper choice of machining parameters has a significant impact on thermal conductivity, durability, hardness, stiffness and roughness of the mold. The proposed methodology was implemented on three different test cases (beverage plastic bottles molds) and it was concluded that even the same machining parameter values offer the same mold quality.

Abstract: A prosthetic replaces any missing human body part visibly and also aims to resume the normal functionality of the part. Reverse engineering extracts information from a present model or available design and develops a new model using advanced CAD tools. Nowadays the reverse engineered part can be combined with rapid prototyping by various software and integration of CAD-CAM platforms. In this paper, a new method to reverse engineer the residual limb information for lower limb amputees, in order to use it for analyzing and developing a prosthetic socket by scanning and developing a CAD model is proposed. Along this are discussed, the advantages and challenges. This work falls in the emerging field of interdisciplinary engineering, combining medical and advanced mechanical engineering on a humanitarian platform

Abstract: An apparatus is developed in this paper, which surveys the motion law of the CAM follower. The apparatus is comprised of the frame body, motors, transmission system, execution system, control system and data acquisition system. The displacement curve, speed curve and acceleration curve of CAM are drawn by analyzing the signal from the dial indicators. This apparatus can provide technical data for the mechanical principle course as well as scientific research work.

Abstract: This paper presents research on the influence of CAM strategies for wear and durability of milling tools. We used two machining principles in this process. In the first instance was constant point of contact with the tool and machining surface. The second method was changing point of the cutting edge in the milling process. Material of tool was hard alloy and high speed steel for machining steel 40CrMnMo7 and C45. The shape of cutting tool was a “Ball Nose” end mill. A DMU 85 monoBLOCK 5-axis CNC milling machine was used. The cutting tool wear was measured in Zoller Genius 3, universal measuring machine and digital microscope, Dino lite 2. The results show differences of cutting tool wear depending on the milling strategy and material of tool.

Abstract: The existing manufacturing technology of small mechanisms elements (gears, gear racks, displacers, bushings, precise mechanical parts, implants) is based on standard material removal techniques (turning, milling etc.). The problem is a variety of a polyamide materials chemical composition. Each additive has a significant influence to the material machinability in technological process. In a result it changes also resistance for melting of material in heat influence area. The method is based on automatically adaptation of parameters with author GRIP NC software and repeatable check of outer layer surface quality in various conditions and cutting strategies. Siemens NX Manufacturing module was used as a tool for operation simulation, parameters correction and G-code post processing tool. Fast G-code Generations gives possibility not only of parameters correction (that can be easily made in G-code itself) but also to optimize trajectory. Iterative comparison of surface roughness and chip flow monitoring were the main criteria that decided of cutting speed modification. On the output of the proposed method the proper cutting parameters table was prepared as well as a set of manufacturing recommendations. The case study is oriented to three polyamide modified materials: ERTHALON 6 PLA PA 6G, ERTALON LFX PA 6G (oil additive) NYLATRON GSM IPA 6 (MoS2 additive). Each material has a different set of fitted cutting parameters. Achieved results could be the guidance and provide proper outer surface roughness for (rough and finish) cutting operations like: axial and radial turning, threading and cutting.

Abstract: In industry, the special kind of trajectory is often designed to fit the desired motion required. In literature, four-bar mechanism is popularly applied and well studied in the trajectory generation. Different types of trajectories are generated by the choose of the ratio of links. The five-bar mechanism is another popular one to generate the desired trajectory and it is more flexible due to it has two degrees of freedom. The geared five-bar mechanism is then commonly used by reducing the degree of freedom of the mechanism into one by implied one pair of gear. In this study, the trajectories generated by a novel cam driven five-bar mechanism proposed by the authors are investigated. It could supply more choices in the application of trajectory generation.