APPROXIMATION ALGORITHM FOR MULTIPLE-TOOL MILLING

2001 ◽  
Vol 11 (03) ◽  
pp. 339-372 ◽  
Author(s):  
SUNIL ARYA ◽  
SIU-WING CHENG ◽  
DAVID M. MOUNT
Keyword(s):  
Approximation Algorithm ◽  
Computer Aided Design ◽  
Minimum Cost ◽  
Cnc Milling ◽  
Automated Generation ◽  
Polynomial Time Approximation Algorithm ◽  
Milling Tool ◽  
Milling Machines ◽  
Aided Design ◽  
Milling Tools

Milling is the mechanical process of removing material from a piece of stock through the use of a rapidly spinning circular milling tool in order to form some desired geometric shape. An important problem in computer-aided design and manufacturing is the automated generation of efficient milling plans for computerized numerically controlled (CNC) milling machines. Among the most common milling problems is simple 2-dimensional pocket milling: cut a given 2-dimensional region down to some constant depth using a given set of milling tools. Most of the research in this area has focused on generating such milling plans assuming that the machine has a tool of a single size. Since modern CNC milling machines typically have access to a number of milling tools of various sizes and the ability to change tools automatically, this raises the important optimization problem of generating efficient milling plans that take advantage of this capability to reduce the total milling time. We consider the following multiple-tool milling problem: Given a region in the plane and a set of tools of different sizes, determine how to mill the desired region with minimum cost. The problem is known to be NP-hard even when restricted to the case of a single tool. In this paper, we present a polynomial-time approximation algorithm for the multiple-tool milling problem. The running time and approximation ratio of our algorithm depend on the simple cover complexity (introduced by Mitchell, Mount, and Suri) of the milling region.

Representing Relationships in Hierarchical Assemblies

1998 ◽  
Author(s):  
Jeff Heisserman ◽  
Raju Mattikalli
Keyword(s):  
Automated Reasoning ◽  
Computer Aided Design ◽  
Design System ◽  
Design Tools ◽  
Cad Tools ◽  
Automated Generation ◽  
Aircraft Systems ◽  
Computer Aided ◽  
Aided Design ◽  
Prototype Design

Abstract Computer aided design tools are gaining popularity in industry due to their ability to model the geometric aspects of products. This has shown substantial benefit for reducing the need and expense of building physical prototypes and allowing parts and tooling to be manufactured directly from these models. However, the current capabilities in existing CAD tools for modeling assemblies are quite limited. In this paper we introduce a representation for describing interfaces between parts within hierarchical assemblies for capturing functional and physical mating relations. This representation is designed to support automated reasoning and automated generation and modification of assemblies. It is also designed for use with very large assemblies, compactly representing the interfaces of parts and assemblies that are reused within larger assemblies. We describe how this representation is used in our prototype design system, Genesis, for designing aircraft systems.

Determination of the Milling Conditions of a Pump Casing Cover Using a Parametric Designed Fixture Device

2015 ◽  
Vol 809-810 ◽  
pp. 890-895
Author(s):  
Ionuţ Ghionea ◽  
Adrian Ghionea ◽  
Saša Ćuković ◽  
Nicolae Ionescu
Keyword(s):  
Working Conditions ◽  
Computer Aided Design ◽  
Fem Analysis ◽  
Milling Process ◽  
Milling Tool ◽  
Cutting Force Components ◽  
Force Components ◽  
Aided Design ◽  
Tool Diameter

This paper presents an applicative methodology of parametric computer aided design using the CATIA v5 software to model and assembly a modular fixture device. The device is then used in the orientation and clamping a part of type casing cover which has a face machined by milling. Having a constructive solution of the fixture device, the next step is to simulate a milling process through a FEM analysis to identify the working conditions: milling tool diameter, number of teeth, cutting forces, required power of the machine tool etc. Some parameters were chosen according to various tools manufacturers catalogues and the cutting force components were determined experimentally in laboratory conditions. The analysis results show that in the FEM simulated milling process, in all the fixture device parts, some tensions cause displacements that have an influence over the casing cover surface roughness.

scholarly journals On Vibration Joint Time-Frequency Investigations of CNC Milling Machines for Tool Trajectory Task Conformity Estimation

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Silviu Nastac
Keyword(s):  
Spectral Characteristics ◽  
Experimental Tests ◽  
Vibration Monitoring ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Shape Accuracy ◽  
Time Frequency ◽  
Milling Tool ◽  
Milling Machines ◽  
Acceleration Signals

This study deals with estimation of milling shape accuracy and trajectory conformity for small CNC 3D milling machines, based on vibration monitoring during the regular working cycles. The author made a large number of experimental tests, acquiring the acceleration signals, both on the milling tool-holder and on the bed frame. In order to evaluate the appropriate spectral characteristics of different machine parts and their weights on equipment dynamics, it was analyzed both the complete and the partial working cycle (such as forward tool motion, with or without effective milling, with or without tool driving, exclusively the milling cutter transitory/stabilized regime) for different basic milling shapes. The acceleration signals were jointly time-frequency investigated in order to evaluate specific spectral indicators related to the real motion characteristic of milling tool. It was used short time fast Fourier transform (STFFT) and Hough transform (HT) algorithms, along with stochastic evaluation of signal parameters, within time and frequency domains. The results reveal an accurate correlation between the specific transitory dynamics of the machine and the imposed milling shape. Main implications of the results within this analysis involve the noninvasive and facile investigation for milling errors of the CNC machine, conformity of tool head trajectory, identification of potential failure source, or damaged machine part.

scholarly journals Computer Engineering Complete Dentures Workflow: Systematic Techniques Review

2021 ◽  
pp. 207-220
Author(s):  
Mohammed M. Al Moaleem ◽  
Omaima A. Al-layl ◽  
Manar A. Alhomood ◽  
Walaa A. Ageeli ◽  
Alzhouor A. Qsadi ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Computer Engineering ◽  
Alphabetical Order ◽  
Dental Practitioners ◽  
Computer Aided ◽  
Milling Machines ◽  
Cad Cam ◽  
Subtractive Manufacturing ◽  
Aided Design ◽  
Digital Denture

Background: The progress in the use of computer-aided design/computer aided manufacturing (CAD/CAM) to fabricat removable prosthodontic prostheses in dental clinics has been exponential. Commercially existing CAD/CAM denture techniques grow every year with increasing benefits to dentists and patients. Study Design: Systematic review. Aims: This review assessed and evaluated the different clinical production protocols of presently accessible CAD/CAM denture systems that offer decision support for dental practitioners. Methodology: Data   for the current object were collected by surveys from different companies manufacturing the Computer Engineering Complete Denture (CECDs). All related subjects published at the last 10 years were collected and included in this review. Techniques were arranged in alphabetical order, as follows. AvaDent Digital Dentures (Global Dental Science), Baltic Denture Creator System (Merz Dental GmbH), and Ceramill Full Denture System (Amann Girrbach AG) can manufacture denture fabrication in three visits, including a try-in step. DENTCA Digital Dentures (Whole You Nexteeth, Inc) can also perform this in three visits. The Wieland Digital Denture (Ivoclar Vivadent, Inc) can manufacture in four dental appointments. Recently developed VITA VIONIC Digital System (VITA Zahnfabrik, Bad Säckingen, Germany) can perform two-step CECD manufacturing. Results: Most of the systems involved subtractive manufacturing for the fabrication of their dentures and only closed systems. However, Baltic Denture System and VITA VIONIC material types are an open structure that allow users to choose among different handling protocols. It can be shared with several unclosed digital scanner, CAD software options, and milling machines. Conclusions: The six existing CECD fabrication systems offer many advantages. The decision on which technique to use may be contingent on the dentist’s prosthodontic expertise, patient output amount, and requirements concerning denture individualization.

scholarly journals Smart surgical template models for customized knee joint replacements

2021 ◽  
Vol 7 (2) ◽  
pp. 129-132
Author(s):  
Philipp Sembdner ◽  
Bernhard Bust ◽  
Lars Dornheim ◽  
Stefan Holtzhausen ◽  
Ralph Stelzer
Keyword(s):  
Computer Aided Design ◽  
Methodological Approach ◽  
Selective Laser Sintering ◽  
Patient Specific ◽  
Joint Replacements ◽  
Automated Generation ◽  
Planning And Design ◽  
Patient Specific Instruments ◽  
Aided Design ◽  
Medical Planning

Abstract The paper introduces a method for the automated generation of patient-specific instruments (PSI), here in particular templates, for the implantation of customized implants. The basis is the derivation of data from the morphology of the bony situation and the medical planning. A developed methodological approach based on an Active Shape Model (ASM) is used for the morphological measurement. Determined geometric dimensions are placed on this ASM and automatically adjusted in each case. In addition, specially developed software tools for the planning and design of medical devices will be presented. This includes, among other things, the intuitive control of template parameters by the user when manual adjustments are necessary. The determined data is bundled and applied to previously methodically thought-out and categorized master CAD (Computer Aided Design) models of surgical templates. These master models are fully configurable and designed to be adjusted within defined ranges of values. The templates are printed from the biocompatible material PA12 using selective laser sintering (SLS).

Embedded Networks Design and Simulation

2020 ◽  
pp. 77-118
Author(s):  
Valentin Olenev ◽  
Yuriy Sheynin ◽  
Irina Lavrovskaya ◽  
Ilya Korobkov ◽  
Lev Kurbanov ◽  
...  
Keyword(s):  
Network Design ◽  
Computer Aided Design ◽  
Local Area ◽  
Design System ◽  
Embedded Networks ◽  
Automated Generation ◽  
Simulation Tools ◽  
Cad System ◽  
Aided Design ◽  
Structure Configuration

This chapter presents an approach for the design and simulation of embedded networks for spacecraft. The chapter provides an analysis of existing simulation tools for the on-board and local area networks. The authors overview the main abilities of the existing software and then propose the computer-aided design system for SpaceWire onboard networks design and simulation. This CAD system supports the full on-board network design and simulation flow, which begins from the network topology automated generation and finishes with getting the network structure, configuration and parameters setting, simulation results, and statistics – SpaceWire Automated Network Design and Simulation (SANDS). The authors describe formal theories, algorithms, methods, and approaches, which are used to solve general issues that appear in developing of onboard networks. The chapter covers topics of fault-tolerance in onboard networks, discusses routing problems, and approaches to organize deadlock-free routing. The authors propose schedule creation algorithms for STP ISS protocol and consider network simulation issues.

scholarly journals Where Does CAM Stand?

2007 ◽  
Vol 129 (01) ◽  
pp. 30-32
Author(s):  
Jean Thilmany
Keyword(s):  
Computer Aided Design ◽  
Manufacturing Industry ◽  
Human In The Loop ◽  
Computer Aided ◽  
Milling Machines ◽  
Mold Making ◽  
Molded Parts ◽  
Cad Models ◽  
Manufacturing Software ◽  
Aided Design

This article describes various engineering ways to use computers in manufacturing industry. Streamlining computer-aided design (CAD) and computer-aided manufacturing (CAM) handoff has long been the dream of engineering organizations that face handoff issues every day. The company, Protomold Co. Inc., ties CAD directly with CAM, to do away with requiring a human in the loop. It makes plastic injection-molded parts from customers’ CAD models. A Minnesota company has nearly automated its mold making. Software designs the mold automatically and automatically commands milling machines. The article also highlights that CAM systems of the future should include easy workarounds that any company could use to customize the software. Like other computer-aided engineering applications, manufacturing software is being pushed forward, although innovation and research is mainly the purview of academics. Researchers are focusing on considering rapid prototyping for making CAD and CAM work together in future.

Multidisziplinäre Entwicklung eines robotergeführten Schwingungskompensators/Multidisciplinary Development of a Robot-guided Vibration Compensator

Konstruktion ◽  
2015 ◽  
Vol 67 (07-08) ◽  
pp. 86-90
Author(s):  
P. Kostka ◽  
R. Höhne ◽  
K. Holeczek ◽  
M. Krahl ◽  
W. Hufenbach
Keyword(s):  
Computer Aided Design ◽  
Milling Process ◽  
Industrial Robots ◽  
Large Variability ◽  
Reinforced Plastic ◽  
Finite Elemente ◽  
Milling Machines ◽  
Comprehensive Development ◽  
Efficient Alternative ◽  
Aided Design

Die gängigen Systeme zur spanenden Bearbeitung von groß-volumigen Bauteilen aus Faserkunststoffverbunden (FKV) basieren auf mehrachsigen Portalfräsanlagen. Eine kosten- und energieeffiziente Alternative bietet der Einsatz von In- dustrierobotern. Aufgrund der geringen Steifigkeit gängiger Roboter in Kombination mit den hochvariablen Schnittkräften bei der Bearbeitung von inhomogenen FKV, kann eine für Industriestandards hinreichende Bearbeitungsqualität bisher jedoch nicht erreicht werden. In diesem Artikel wird die Entwicklung eines adaptiven, modularen Schwingungskompensators zur Reduktion prozessbedingter Schwingungen vorgestellt. Dazu wurde eine iterative Simulationsprozedur durch Kopplung von rechnergestützem Design-, Finite-Elemente- und Mehr-körper-Modell angewendet und experimentell validiert.   The common systems for the machining of large-volume fibre-reinforced plastic (FRP) components are based on multiaxis portal milling machines. Cost and energy efficient alternative is the use of industrial robots. Due to the lower stiffness of common industrial robots combined with the large variability of cutting forces during processing of inhomogeneous FRPs, a satisfactory machining quality could not been achieved. This paper presents a comprehensive development of a modular self-adapting vibration compensator used for the reduction of milling process-born vibrations. Herein, an iterative simulation procedure using coupled Computer-Aided Design, Finite-Element and multibody models was applied and experimentally validated.

Manufacture of Custom Contoured Seat Cushions Using Computer-Aided Design Computer-Aided Manufacturing (CAD/CAM) Technique

2011 ◽  
Vol 201-203 ◽  
pp. 342-346
Author(s):  
Singare Sekou
Keyword(s):  
Pressure Ulcer ◽  
Computer Aided Design ◽  
Depth Of Cut ◽  
Surface Model ◽  
Cad Model ◽  
Cnc Milling ◽  
3D Surface ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

In the rehabilitation engineering area, the pressure ulcer prevention is an important and healthy problem, especially for people with the spinal cord injured (SCI). This paper aim to develop a computer aided design and computer aided manufacture (CAD/CAM) method to manufacture custom cushions to prevent pressure ulcer. A patient’s buttock was digitized using 3D laser scanner, and the captured buttock data was processed in reverse engineering environment to generate the 3D surface model of the buttock. The 3D surface model of the buttock is imported into Unigraphics software to create the solid model; then, a flat rectangle that represents the cushion was generated under the buttock to create the buttock-cushion system. Based on the load-deformation relation of cushion materials acquired by the test, the depth of cut of the cushion was established and a CAD model of cushion shape was created through a Boolean subtraction. The CAD model of the contour is post-processed into code that the numerically controlled milling machine (CNC milling) can use to machine the cushion.

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