Implementing Rapid Prototyping Using CNC Machining (CNC-RP) Through a CAD/CAM Interface

This paper presents the methodology and implementation of a rapid machining system using a CAD/CAM interface. Rapid Prototyping using CNC Machining (CNC-RP) is a method that has been developed which enables automatic generation of process plans for a machined component. The challenge with CNC-RP is not the technical problems of material removal, but with all of the required setup, fixture and toolpath planning, which has previously required a skilled machinist. Through the use of advanced geometric algorithms, we have implemented an interface with a CAD/CAM system that allows true automatic NC code generation directly from a CAD model with no human interaction; a capability necessary for a practical rapid prototyping system.Mechanical Engineerin

Fabrication of Nonplanar Surfaces Via 5-Axis 3D Printing

The advancements in manufacturing have always played a vital role in human life. One of the most recent and growing manufacturing methods is additive manufacturing (AM). AM has been in focus for its ability to manufacture intricate parts with internal features which are not possible with traditional manufacturing processes. Making parts lighter and stronger has been the goal for most AM processes. The advancements in AM have made it possible to produce parts with high strength internal structures. The overall strength of the manufactured plastic parts depends on several variables. The part’s strength is determined by the material, the build direction, the infill settings, and the printing parameters. Optimization of each of these variables is critical for obtaining the desired result for the intended application of the printed part. One of the major drawbacks of these parts is the weak interlayer bonding within parts which are susceptible to failure under high loads. Similarly, the stair stepping effect compromises the surface finish of a part. This is prominently seen when the angle of inclination is less than 30 degrees. Previous research shows that the mixture of non-planar and planar layers in a 3DP part can improve its surface finish. Non-Planar 3D printing done using a 3-axis machine is limited by the angle of the nozzle with respect to the previously printed layers. This study will focus on incorporating 5-axis 3D printer toolpath motions to print nonplanar surfaces. It will also shed some light on the enhanced mechanical properties of the parts which have non-planar layers as compared to conventionally 3D printed parts

An eXtended Manufacturing Integrated System for feature based manufacturing with STEP-NC

International audienceCNC feature-based programming with STEP-NC standard extends the collaborative model of manufacturing data exchange all along the numerical data chain. This paper considers the mutations related to this approach from the manufacturing system level to the industrial enterprise as a whole. The eXtended Manufacturing Integrated System concept is introduced to fill in the gap of the current manufacturing data exchange bottleneck. It is composed of eXtended CAD and eXtended CNC systems to link the CAD model to the real machined part through the Manufacturing Information Pipeline. The contributions associated with these concepts are demonstrated through a validation platform implemented on industrial CNC manufacturing equipments

Development of working procedures of a 5 Axis CNC milling machine

Dissertação de mestrado em Mechanical EngineeringThe work developed and presented on this dissertation tends to the installation and configurations of a 5-axis CNC machine with the creation of working procedures intended to build a stable workflow that can be employed by any individual expected to use the machine. Being a large field within mechanical engineering as well as being involved in a large selection of different industrial sectors, the concept of 5-axis machining will be explored to develop knowledge in terms of CAM programming and manipulation/optimization of toolpaths. The importance/functioning of the transmission of information both from post-processor to the controller and from the controller to the actual machine is also a critical point in this work as they are directly related to the quality of the parts produced. To accomplish this, the theoretical knowledge foundations regarding CNC machining work were researched, studied, and explained. Furthermore, the machine model in question (HY-6040 5-axis CNC Router) was meticulously analysed regarding to the machines structure, post-processor, and controller. Upon assembling all this information, and through the production of some test parts, a permanent manufacture workflow for different machining approaches was established and described.O trabalho desenvolvido e apresentado nesta dissertação tende à instalação e configuração de uma máquina CNC de 5-eixos, com a criação de procedimentos de trabalho destinados a criar um fluxo de trabalho estável que possa ser empregue por qualquer individuo que pretenda utilizar a máquina. Sendo um grande campo dentro da engenharia mecânica e estando também envolvido numa grande seleção de diferentes setores industriais, o conceito de maquinagem em 5-eixos será explorado com a finalidade de desenvolver conhecimentos a nível de programação CAM e manipulação/otimização de trajetórias de corte. A importância/funcionamento da transmissão de informação quer do pôs-processador para o controlador, quer do controlador para a máquina constituem também um ponto critico neste trabalho já que estão diretamente relacionados com a qualidade das peças produzidas. Para a realização de tal, foram pesquisados, estudados e explicados os fundamentos do conhecimento teórico relativamente ao trabalho de maquinagem CNC. Para além disso, o modelo da máquina em questão (HY-6040 5-axis CNC Router) foi meticulosamente analisado quanto à estrutura da máquina, pós-processador e controlador. Após reunir toda esta informação, e través da produção de peças teste, foi estabelecido um fluxo de trabalho de manufatura (CAD/CAM/Maquinagem) para diferentes abordagens de maquinagem

Real-Time Jerk Limited Feedrate Profiling and Interpolation for Linear Motor Multiaxis Machines Using NURBS Toolpaths

In this article, a NURBS toolpath feedrate profile generation algorithm for a biaxial linear motor control system is presented. High achievable velocities and accelerations of linear motor machines present new computational challenges in implementing feedrate generation and toolpath interpolation algorithms in real-time controllers. The proposed algorithm is capable of online generation of the feedrate profile with axial acceleration and jerk constraints. Each stage of the feedrate profiling algorithm is described with attention being given to both performance and implementation aspects. Furthermore, an alternative to the commonly used Taylor series interpolation method is also tested to ensure minimal interpolation errors. The feedrate profiling and interpolation algorithms’ implementation in a PC-based controller with real-time Linux kernel is described. Experimental results are presented that confirm that the algorithm is capable of limiting acceleration and jerk in the machine’s axes and it is low computation time enables real-time on-line operation in a PC-based CNC controller

Computer numerical control machine tool information reusability within virtual machining systems

Virtual Machining (VM) allows simulation of the machining process by realistically representing kinematic, static and dynamic behaviour of the intended machine tools. Using this method, manufacturing related issues can be brought to light and corrected before the product is physically manufactured. Machining systems utilised in the manufacturing processes are represented in the VM environment and there is a plethora of commercial VM software used in the industry. Each software system has a different focus and approach towards virtual machining; more than one system may be needed to complete machining verification. Thus, the significant increase in the use of virtual machining systems in industry has increased the need for information reusability. Substantial time and money has been put into the research of virtual machining systems. However, very little of this research has been deployed within industrial best practice and its acceptance by the end user remains unclear. This paper reviews current research trends in the domain of VM and also discusses how much of this research has been taken on board by software venders in order to facilitate machine tool information reusability. The authors present a use cases which utilises the novel concept of Machining Capability Profile (MCP) and the emerging STEP-NC compliant process planning framework for resource allocation. The use cases clearly demonstrate the benefits of using a neutral file format for representing MCPs, as opposed to remodelling and or reconfiguring of this information multiple times for different scenarios. The paper has shown through the use cases that MCPs are critical for representing recourse information from a kinematic, static and dynamic perspective that commercial software vendors can subsequently use. The impact of this on mainstream manufacturing industry is potentially significant as it will enable a true realisation of interoperability