Computing the Global Visibility Map Using Slice Geometry for Setup Planning

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Guangyu Hou ◽  
Matthew C. Frank
Keyword(s):  
High Performance ◽  
Cnc Machining ◽  
Numerical Control ◽  
Cnc Milling ◽  
Setup Planning ◽  
Visibility Map ◽  
Axis Of Rotation ◽  
Milling Machines ◽  
Hard Problems ◽  
Rotation Map

This paper introduces a new method that uses slice geometry to compute the global visibility map (GVM). Global visibility mapping is a fundamentally important process that extracts geometric information about an object, which can be used to solve hard problems, for example, setup and process planning in computer numerical control (CNC) machining. In this work, we present a method for creating the GVM from slice data of polyhedron models, and then show how it can help determine around which axis of rotation a part can be machined. There have been various methods of calculating the GVM to date, tracing back to the well-known seminal methods that use Gaussian mapping. Compared to the considerable amount of work in this field, the proposed method has an advantage of starting from feature-free models like stereolithography (STL) files and has adjustable resolution. Moreover, since it is built upon slicing the model, the method is embarrassingly parallelizable in nature, thus suitable for high-performance computing. Using the GVM obtained by this method, we generate an axis of rotation map to facilitate the setup planning for four-axis CNC milling machines as one implementation example.

One Touch Workpiece Verification System for CNC Machining Using a Low-Cost Computer Vision Approach

2016 ◽  
Author(s):  
Maxwell K. Micali ◽  
Hayley M. Cashdollar ◽  
Zachary T. Gima ◽  
Mitchell T. Westwood
Keyword(s):  
Computer Vision ◽  
Low Cost ◽  
Cnc Machining ◽  
Potential Operator ◽  
Cnc Milling ◽  
Machining Processes ◽  
Loop Control ◽  
Operator Error ◽  
Verification System ◽  
Milling Machines

While CNC programmers have powerful tools to develop optimized toolpaths and machining plans, these efforts can be wholly undermined by something as simple as human operator error during fixturing. This project addresses that potential operator error with a computer vision approach to provide coarse, closed-loop control between fixturing and machining processes. Prior to starting the machining cycle, a sensor suite detects the geometry that is currently fixtured using computer vision algorithms and compare this geometry to a CAD reference. If the detected and reference geometries are not similar, the machining cycle will not start, and an alarm will be raised. The outcome of this project is the proof of concept of a low-cost, machine/controller agnostic solution that is applied to CNC milling machines. The Workpiece Verification System (WVS) prototype implemented in this work cost a total of $100 to build, and all of the processing is performed on the self-contained platform. This solution has additional applications beyond milling that the authors are exploring.

scholarly journals An Overview of process CNC Machining

2020 ◽  
Vol 6 (2) ◽  
pp. 029-033
Author(s):  
Herick Henci Agrisa
Keyword(s):  
Computer Aided Design ◽  
The United States ◽  
Cnc Machining ◽  
Numerical Control ◽  
Numerical Code ◽  
Massachusetts Institute Of Technology ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cnc Machines ◽  
Computer Aided

This paper discusses the pre and process of running a computer numerical control machine (CNC) using computer-aided design (CAD) software commonly used to design products to be produced and computer-aided manufacture (CAM) software used to control machines during the manufacturing process. Some types of CNC machines in general, namely CNC lathe machine and CNC milling machine. The history of the development of the CNC Machine was begun in 1952 by John Pearseon of the Massachusetts Institute of Technology on behalf of the United States Air Force, which aims to make complicated special workpieces. In addition, this paper also discusses the basic numerical code types used in CNC machines.

scholarly journals Reducing the Risks during the Purchase of Five-Axis CNC Machining Centers Using AHP Method and Fuzzy Systems

2019 ◽  
Vol 11 (2) ◽  
pp. 315 ◽  
Author(s):  
Lucian-Ionel Cioca ◽  
Radu-Eugen Breaz ◽  
Sever-Gabriel Racz
Keyword(s):  
Fuzzy Systems ◽  
Setup Time ◽  
Traverse Speed ◽  
Cnc Machining ◽  
Numerical Control ◽  
Cnc Milling ◽  
Analytic Hierarchy ◽  
Numerical Control Machining ◽  
Five Axis ◽  
Hierarchy Process

Nowadays, companies are in the process of renewing their manufacturing lines by equipping them with modern five-axis CNC (computer numerical control) machining centers. The decision to select between different five-axis CNC machining centers, with similar technological capabilities is a difficult process, so the main goal of this work was to develop a method for assisting it. The proposed approach relies on seven technical criteria, four quantitative ones (traverse speed, thrust, spindle power, and spindle speed) which can be expressed by crisp numerical values, while the other three (flexibility, operation easiness, and setup time) are qualitative ones. The analytic hierarchy process (AHP) was used for ordering four variants of five-axis CNC milling machining centers. The qualitative criteria were processed using fuzzy systems to be expressed by crisp numerical values, suitable for AHP. Finally, the four variants of five-axis CNC milling machining centers were hierarchized and the best one was chosen. A sensitivity analysis was also unfolded to certify the robustness of the AHP.

scholarly journals Wear Resistance, Color Stability and Displacement Resistance of Milled PEEK Crowns Compared to Zirconia Crowns under Stimulated Chewing and High-Performance Aging

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3761
Author(s):  
Simone Shah Abhay ◽  
Dhanraj Ganapathy ◽  
Deepak Nallaswamy Veeraiyan ◽  
Padma Ariga ◽  
Artak Heboyan ◽  
...  
Keyword(s):  
Wear Resistance ◽  
High Performance ◽  
Color Stability ◽  
P Value ◽  
Cnc Milling ◽  
Promising Alternative ◽  
Stl File ◽  
Milling Machines ◽  
Zirconia Crowns ◽  
Five Axis

Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon–Mann–Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value < 0.05). Zirconia had twice the wear resistance of PEEK (p value < 0.05). Zirconia was more color stable than PEEK (p value < 0.05). PEEK had more displacement resistance than zirconia (p value < 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown.

Design and Implementation of an Interpolation Processor for CNC Machining

2013 ◽  
Vol 819 ◽  
pp. 322-327
Author(s):  
Jing Chuan Dong ◽  
Tai Yong Wang ◽  
Bo Li ◽  
Xian Wang ◽  
Zhe Liu
Keyword(s):  
Real Time ◽  
High Speed ◽  
High Performance ◽  
Low Cost ◽  
Parallel Architecture ◽  
Cnc Machining ◽  
Numerical Control ◽  
Experimental Result ◽  
Interpolation Algorithm ◽  
Asynchronous Instruction

As the demand for high speed and high precision machining increases, the fast and accurate real-time interpolation is necessary in modern computerized numerical control (CNC) systems. However, the complexity of the interpolation algorithm is an obstacle for the embedded processor to achieve high performance control. In this paper, a novel interpolation processor is designed to accelerate the real-time interpolation algorithm. The processor features an advanced parallel architecture, including a 3-stage instruction pipeline, very long instruction word (VLIW) support, and asynchronous instruction execution mechanism. The architecture is aimed for accelerating the computing-intensive tasks in CNC systems. A prototype platform was built using a low-cost field programmable gate array (FPGA) chip to implementation the processor. Experimental result has verified the design and showed the good computing performance of the proposed architecture.

scholarly journals IMPROVEMENT OF THE COLLECTOR OUTPUT DEVICE OF THE DISK SEPARATORS

2019 ◽  
Vol 19 (2) ◽  
pp. 48-50
Author(s):  
L. S. SOLDATENKO ◽  
I. OSTROVKYI
Keyword(s):  
High Performance ◽  
Small Scale ◽  
Input Device ◽  
Wild Oat ◽  
Cnc Milling ◽  
Technical Literature ◽  
Wheat Grains ◽  
Milling Machines ◽  
Oat Seeds ◽  
Working Bodies

Disk separators operate on the basis of selective removal of a short fraction grain from a mixture with longer ones, for example, darnel grains and similar impurities from a mixture of wheat grains; or wheat grains from a mixture of wild oat seeds and other longer waste particles. For this purpose, the working bodies of separators— cylinders or disks — are equipped with special cavities, so called “cells”, which location, shape and size correspond to the technological operation. In the flow lines of the grain cleaning workshops of high performance flour mills, predominantly, disk separators, which construction and productivity are well-known from the scientific and technical literature, are used. In recent decades, the improved, so-called small-scale disk separators for wild oat, for example, A9-УТО-6 and some others, have been created and become widely used. Their specialties include, in particular, the lack of interdisciplinary trays in the pre-configured prefabricated input device (i.e., they are characterized by the use of unblocked WUAs). Further improvement of an unblocked WUA is possible on the basis of “The grain mixture cleaning method", which involves the location of cells on the surface of the discs, which ensures that the short particles fall out of them with a compact beam at the same angle, regardless of the distance of the cell relative to the axis of rotation. Therefore, the casting model of the disc should receive a more complex construction, which, unlike the present, mainly manual technology, is expedient to use with modern CNC milling machines.

scholarly journals Application of precedence constrained travelling salesman problem model for tool path optimization in CNC milling machines

2019 ◽  
Vol 9 (3) ◽  
pp. 59-68
Author(s):  
Ilker Kucukoglu ◽  
Tulin Gunduz ◽  
Fatma Balkancioglu ◽  
Emine Chousein Topal ◽  
Oznur Sayim
Keyword(s):  
Optimization Problem ◽  
Tool Path ◽  
Travelling Salesman Problem ◽  
Numerical Control ◽  
Path Optimization ◽  
Cnc Milling ◽  
Travelling Salesman ◽  
Tool Path Optimization ◽  
Milling Machines ◽  
Internal Operations

In this study, a tool path optimization problem in Computer Numerical Control (CNC) milling machines is considered to increase the operational efficiency rates of a company. In this context, tool path optimization problem of the company is formulated based on the precedence constrained travelling salesman problem (PCTSP), where the general form of the TSP model is extended by taking the precedence of the tool operations into account. The objective of the model is to minimize total idle and unnecessary times of the tools for internal operations. To solve the considered problem, a recent optimization algorithm, called Satin Bowerbird Optimizer (SBO), is used. Since the SBO is first introduced for the global optimization problems, the original version of the SBO is modified for the PCTSP with discretization and local search procedures. In computational studies, first, the performance of the proposed algorithm is tested on a well-known PCTSP benchmark problems by comparing the proposed algorithm against two recently proposed meta-heuristic approaches. Results of the comparisons show that the proposed algorithm outperforms the other two competitive algorithms by finding better results. Then, the proposed algorithm is carried out to optimize the hole drilling processes of three different products produced by the company. For this case, with up to 4.05% improvement on the operational times was provided for the real-life problem of the company. As a consequence, it should be noted that the proposed solution approach for the tool path optimization is capable of providing considerable time reductions on the CNC internal operations for the company.

Use of laser technologies for restoration, documentation and replication of sculptural monuments in Saint Petersburg

2020 ◽  
Vol 62 (3) ◽  
pp. 129-133
Author(s):  
V A Parfenov
Keyword(s):  
Laser Scanning ◽  
Computer Modelling ◽  
Numerical Control ◽  
Cnc Milling ◽  
Heritage Preservation ◽  
Saint Petersburg ◽  
Combined Use ◽  
Milling Machines ◽  
New Perspective ◽  
Cultural Heritage Preservation

This paper presents a brief overview of the most important case studies concerned with the use of laser techniques for documentation, replication and reconstruction of outdoor sculptural monuments in Saint Petersburg, Russia. These studies have been conducted by a research group of scientists, students and PhD students from Saint Petersburg Electrotechnical University (LETI), in cooperation with specialists from museums and private restoration companies. It is shown that the combined use of 3D laser scanning, computer modelling, computer numerical control (CNC) milling machines and additive technologies opens up a new perspective in cultural heritage preservation.

Technological Assurance of High-Efficiency Machining of Internal Rope Threads on Computer Numerical Control Milling Machines

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Anna Neshta ◽  
Dmytro Kryvoruchko ◽  
Michal Hatala ◽  
Vitalii Ivanov ◽  
Frantisek Botko ◽  
...  
Keyword(s):  
High Efficiency ◽  
Dimensional Accuracy ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Maximum Efficiency ◽  
Internal Thread ◽  
Cnc Milling ◽  
High Efficient ◽  
Milling Machines ◽  
Machined Parts

The analysis of various methods of machining of rope internal thread ISO 10208, DIN 20317 has been carried out and the criteria of high-efficiency machining have been formulated. The concept of the method has been developed, which supposes the designing of the construction of noncore tool and the calculation of the parameters of mechanical trajectory with the purpose of ensuring the machining per one pass on the computer numerical control (CNC) milling machine. The compensation procedure of dimensional wear of insert has been developed. While machining the production batch of the parts in an experimental way, the optimum cutting conditions have been determined which allow ensuring the maximum efficiency on reaching the required roughness and the dimensional accuracy of the profile of rope thread. The performed statistical analysis of the machined parts allowed to establish that dispersions of the actual values of profiles' roughness follow Gauss' law. In an experimental way, it has been proved that the application of the proposed method increased the efficiency of machining of the internal rope thread by 2.5 times. On the basis of comparison of engineering-and-economical performance, the efficient fields of application of high-efficient method of machining of the rope threads have been determined.

An Accurate and Efficient Approach to Three-Dimensional Geometric Modeling of Undeformed Chips for the Geometric and the Physical Simulations of Three-Axis Milling of Complex Parts

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Zhiyong Chang ◽  
Zezhong C. Chen
Keyword(s):  
Geometric Modeling ◽  
High Performance ◽  
Physical Simulation ◽  
Three Dimensional ◽  
Numerical Control ◽  
Machining Process ◽  
Machining Parameters ◽  
Cnc Milling ◽  
Physical Simulations ◽  
Complex Parts

To pursue high-performance computer numerical control (CNC) milling of complex parts, it is crucial to simulate their machining process geometrically and physically with high fidelity beforehand. The geometric simulation is to construct three-dimensional (3D) models of the finished parts and to compute geometric deviation between the models and the part designs, in order to verify the planned tool paths. The physical simulation is to build undeformed chips geometric models and in-process workpiece models and to compute instantaneous cutting forces, in order to optimize the machining parameters. Therefore, it is essential to accurately and efficiently model undeformed chips geometry in machining complex geometric parts. Unfortunately, this work is quite challenging, and no well-established method for this work is available. To address this problem, our work proposes an accurate and effective approach to 3D geometric modeling of undeformed chips geometry in three-axis milling of complex parts. The outstanding feature of this approach is that undeformed chip models and in-process workpiece models can be effectively constructed. This approach lays a theoretical foundation for the geometric and the physical simulations of three-axis milling. It advances the technique of machining simulation and promotes high-performance machining of complex parts.

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