scholarly journals A “Double Accuracy Theory” and Experimental Research on Precision Grinding

2020 ◽  
Vol 10 (6) ◽  
pp. 2030
Author(s):  
Lai Hu ◽  
Yipeng Li ◽  
Jun Zha ◽  
Yaolong Chen
Keyword(s):  
High Speed ◽  
Coordinate Measuring Machine ◽  
Precision Grinding ◽  
Machined Parts ◽  
Accuracy Theory ◽  
Machine Theory ◽  
Ultra Precision ◽  
Measuring Machine ◽  
Grinding Machine ◽  
Multi Body

In the global machining industry, ultra-precision/ultra-high-speed machining has become a challenge, and its requirements are getting higher and higher. The challenge of precision grinding lies in the difficulty in ensuring the various dimensions and geometric accuracy of the final machined parts. This paper mainly uses the theory of a multi-body system to propose a “double accuracy” theory of manufacturing and measurement. Firstly, the grinding theory with an accuracy of 0.1 μm and the precision three-coordinate measuring machine theory with an accuracy of 0.3 μm are deduced. Secondly, the two theories are analyzed. Aiming to better explain the practicability of the “double accuracy” theory, a batch of motorized spindle parts is processed by a grinding machine. Then the precision three-coordinate measuring machine is used to measure the shape and position tolerances such as the roundness, the squareness, the flatness, and the coaxiality. The results show that the reached roundness of part A and B is 5 μm and 0.5 μm, the squareness is 3 μm and 4.5 μm, and the coaxiality tolerance is 1.2 μm, respectively.

scholarly journals ROBUST ENGINEERING CASE STUDY FOR SIMULTANEOUS PARAMETER OPTIMIZATION OF A DEEP DRILLING PROCESS

2017 ◽  
Vol 45 (1) ◽  
pp. 27
Author(s):  
Laurentiu A Mihail
Keyword(s):  
High Speed ◽  
Coordinate Measuring Machine ◽  
Drilling Process ◽  
Deep Drilling ◽  
Flexible System ◽  
Machined Parts ◽  
Measuring Machine ◽  
Peck Drilling

The paper reflects de overall results of an experiment developed for optimising a deep peck drilling process, using an extra-long flute drill. The problem stated was the dimensional, geometrical and orientation accuracy of the holes machined by the previously mentioned machining method. The target was to improve the quality of the machined parts and to reach the maximum productivity in the same time. The optimisation method used was the Taguchi Method, with a L423 fractionated factorial array. Another important issue was to optimise several quality characteristics, simultaneously. After machining the test part on a high-speed machining flexible system, the parts were measured on a coordinate measuring machine. Finally, the data was computed assisted by an advanced quality software. The simultaneous optimisation was achieved by validated method, through several iterations based on advanced process and design of experiments knowledge. Finally, the conclusions were compared with another results, from the same research program, validating it.

Evaluation of Parts Produced by a Novel Additive Manufacturing Process

2013 ◽  
Vol 315 ◽  
pp. 63-67 ◽  
Author(s):  
Muhammad Fahad ◽  
Neil Hopkinson
Keyword(s):  
Additive Manufacturing ◽  
Rapid Prototyping ◽  
Manufacturing Process ◽  
High Speed ◽  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
Layer By Layer ◽  
Nylon 12 ◽  
Measuring Machine ◽  
End Use

Rapid prototyping refers to building three dimensional parts in a tool-less, layer by layer manner using the CAD geometry of the part. Additive Manufacturing (AM) is the name given to the application of rapid prototyping technologies to produce functional, end use items. Since AM is relatively new area of manufacturing processes, various processes are being developed and analyzed for their performance (mainly speed and accuracy). This paper deals with the design of a new benchmark part to analyze the flatness of parts produced on High Speed Sintering (HSS) which is a novel Additive Manufacturing process and is currently being developed at Loughborough University. The designed benchmark part comprised of various features such as cubes, holes, cylinders, spheres and cones on a flat base and the build material used for these parts was nylon 12 powder. Flatness and curvature of the base of these parts were measured using a coordinate measuring machine (CMM) and the results are discussed in relation to the operating parameters of the process.The result show changes in the flatness of part with the depth of part in the bed which is attributed to the thermal gradient within the build envelope during build.

A Technique for Enhancing Machine Tool Accuracy by Transferring the Metrology Reference From the Machine Tool to the Workpiece

2006 ◽  
Vol 129 (3) ◽  
pp. 636-643 ◽  
Author(s):  
Bethany A. Woody ◽  
K. Scott Smith ◽  
Robert J. Hocken ◽  
Jimmie A. Miller
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
High Speed ◽  
Large Scale ◽  
Thermal Environment ◽  
Coordinate Measuring Machine ◽  
Shop Floor ◽  
Finished Part ◽  
Measuring Machine ◽  
Monolithic Components

High-speed machining (HSM) has had a large impact on the design and fabrication of aerospace parts and HSM techniques have been used to improve the quality of conventionally machined parts as well. Initially, the trend toward HSM of monolithic parts was focused on small parts, where existing machine tools have sufficient precision to machine the required features. But, as the technology continues to progress, the scale of monolithic parts has continued to grow. However, the growth of such parts has become limited by the inability of existing machines to achieve the tolerances required for assembly due to the long-range accuracy and the thermal environment of most machine tools. Increasing part size without decreasing the tolerances using existing technology requires very large and very accurate machines in a tightly controlled thermal environment. As a result, new techniques are needed to precisely and accurately manufacture large scale monolithic components. Previous work has established the fiducial calibration system (FCS), a technique, which, for the first time provides a method that allows for the accuracy of a coordinate measuring machine (CMM) to be transferred to the shop floor. This paper addresses the range of applicability of the FCS, and provides a method to answer two fundamental questions. First, given a set of machines and fiducials, how much improvement in precision of the finished part can be expected? And second, given a desired precision of the finished part, what machines and fiducials are required? The achievable improvement in precision using the FCS depends on a number of factors including, but not limited to: the type of fiducial, the probing system on the machine and CMM, the time required to make a measurement, and the frequency of measurement. In this paper, the sensitivity of the method to such items is evaluated through an uncertainty analysis, and examples are given indicating how this analysis can be used in a variety of cases.

Structural Analysis of a Grinding Machine with Linear Motion Guide Applied

2013 ◽  
Vol 336-338 ◽  
pp. 1014-1019
Author(s):  
Seon Yeol Oh ◽  
Han Seok Bang ◽  
B. Y. Choi ◽  
Woo Chun Choi ◽  
S. J. Cho
Keyword(s):  
Finite Element ◽  
Structural Analysis ◽  
Structural Design ◽  
Element Model ◽  
Linear Motion ◽  
Precision Grinding ◽  
Base Side ◽  
Ultra Precision ◽  
Linear Motion Guide ◽  
Grinding Machine

A finite element model of an ultra-precision grinding machine that can have high precision and high stiffness is constructed and structural analysis is done with equivalent stiffnesses of linear motion guides by after structural design and the deformation of the grinding machine is obtained. In order to reduce the deformation of the grinding machine that causes bad influence, structural complement is conducted by adding ribs at the lower part of the column. Also, the straightness of the grinding machine is improved by lifting that the base side of the column.

Ultra Precision Grinding of Wafer Scale

2012 ◽  
Vol 516 ◽  
pp. 257-262
Author(s):  
Martin Hünten ◽  
Fritz Klocke ◽  
Olaf Dambon ◽  
Benjamin Bulla
Keyword(s):  
Tungsten Carbide ◽  
Surface Topography ◽  
Precision Grinding ◽  
Wafer Scale ◽  
Advantages And Disadvantages ◽  
Grinding Processes ◽  
Ultra Precision ◽  
Grinding Tool ◽  
Glass Optics ◽  
Grinding Machine

Manufacturing moulds for the wafer-scale replication of precision glass optics sets new demands in terms of grinding tool lifetime and the processes to be applied. This paper will present different approaches to grinding processes and kinematics to machine wafer-scale tungsten carbide moulds with diameters of up to 100 mm and more than 100 single aspheric cavities, each featuring form accuracies in the micron range. The development of these processes will be described and advantages and disadvantages of the approaches derived from practical tests performed on an ultra precision grinding machine (Moore Nanotech 350FG) will be discussed. Finally, a comparison between the developed processes is made where achieved form accuracies and surface topography are analyzed.

VERNE - a five-axis parallel kinematics milling machine

2005 ◽  
Vol 219 (3) ◽  
pp. 327-336 ◽  
Author(s):  
M Terrier ◽  
M Giménez ◽  
J-Y Hascoët
Keyword(s):  
High Speed ◽  
Experimental Approach ◽  
Coordinate Measuring Machine ◽  
Direct Consequence ◽  
Numerical Control ◽  
Parallel Kinematics ◽  
High Speed Milling ◽  
Axis Parallel ◽  
Measuring Machine ◽  
Five Axis

Ten years ago a new kind of machine tool was presented in Chicago, based on parallel kinematics architectures. Since then, many of these parallel kinematics machines (PKMs) have been developed around the world. Their main interest lies in their high dynamic characteristics, which could help in going faster in high-speed milling. In order to develop high-speed milling on PKM tools and to highlight their potentialities, the French laboratory IRCCyN is now equipped with the VERNE. This PKM tool has been developed by the Spanish company Fatronik. However, the high-speed milling production process is a complex task, in which a great number of parameters influence the final precision of the part and the productivity of the machine. For example, the NC (numerical control) and computer-aided manufacturing (CAM) parameters (feed forward, milling strategies, etc.), the piece geometry, the machine structure, the tool, etc., have a direct consequence on the final part. Hence, a method has been developed in order to check the capability of the machine (either serial or parallel) in milling, which relies on two approaches. The first one is an experimental approach (either using a coordinate measuring machine or acquiring the output axis encoders), while the second one is a simulated approach. After introducing the kinematics of the VERNE, the experimental approach performed so far will be presented.

Slicing: A Procedure for Tolerance Evaluation of Manufactured Parts Using CMM Measurement Data

1995 ◽  
Author(s):  
Yu Wang ◽  
Shilendra Gupta ◽  
Srinavas Rao
Keyword(s):  
Computational Complexity ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Significant Loss ◽  
Processing Procedure ◽  
Machined Parts ◽  
Measuring Machine ◽  
Part Model

Abstract This paper presents a sampling and processing procedure for tolerance evaluation of machined parts. In this method, deviations of the measured points from their ideal feature surface are evaluated in the plane where the data is measured by a Coordinate Measuring Machine (CMM). This procedure is called slicing. It is shown that the use of the structure inherent in measurement data has a potential in reducing computational complexity for evaluation of certain types of form tolerances without significant loss of accuracy. An application of the proposed method to the development of manufactured part model for automotive spaceframe structures is also discussed.

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