scholarly journals Influence of measuring force on CMM accuracy

2018 ◽  
Vol 208 ◽  
pp. 03004
Author(s):  
Bin Wang
Keyword(s):  
Cross Sections ◽  
Measurement Accuracy ◽  
Coordinate Measuring Machine ◽  
Point Of View ◽  
Signal Acquisition ◽  
Force Model ◽  
Thin Part ◽  
Measuring Machine ◽  
The Relationship ◽  
Measuring Force

The measuring accuracy of CMM (Coordinate Measuring Machine) is influenced by many factors, such as temperature, humidity, measuring force and method of signal acquisition. For thin parts, the influence of measuring force is especially obvious. In this paper, the relationship between measuring force and measurement accuracy is studied for a thin part with a U-shaped cross-section. By analyzing the structure of the probe and establishing the force model, the influencing factors of the accuracy of CMM are obtained, and the influence of the contact deformation and the bending deformation on the measurement accuracy is analyzed from the point of view of material mechanics. At the same time, the measurement accuracy of different measuring cross-sections is analyzed. Through the research of this paper, the relationship between measuring force and CMM is established, and an effective method to improve the accuracy of CMM is also found.

Experimental Investigations for Rapid Moulding Solution of Plastics Using Polyjet Printing

2011 ◽  
Vol 701 ◽  
pp. 15-20 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Support Material ◽  
Economic Point ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate the rapid moulding (RM) solutions for plastic components using polyjet printing (PP) technique. Starting from the identification of component/benchmark, prototypes with three different type of plastic material were produced, at different orientation and support material. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the plastic components produced. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. This process ensures rapid production of pre-series technological prototypes and proof of concept at less production cost and time.

Studies on Design Optimization of Coronary Stents

2008 ◽  
Vol 2 (1) ◽  
Author(s):  
K. Srinivas ◽  
T. Nakayama ◽  
M. Ohta ◽  
S. Obayashi ◽  
T. Yamaguchi
Keyword(s):  
Design Optimization ◽  
Cross Sections ◽  
Latin Hypercube Sampling ◽  
Coronary Stents ◽  
Point Of View ◽  
Two Dimensional ◽  
Reattachment Length ◽  
Design Variables ◽  
Two Dimensional Flow ◽  
The Relationship

The stent design itself seems to be one of the factors responsible for restenosis. As a remedy, the present work attempts to perform a design optimization of coronary stents from a hemodynamic point of view. For the purpose, we have applied the principles of modern exploration of design space restricting ourselves to two-dimensional considerations. Width, thickness, and spacing of the struts of the stent formed the design variables. The objectives chosen for optimization were the vorticity generated, length of recirculation zone, and the reattachment distance in between the struts. Both semicircular and rectangular cross sections of stents were included. Starting with the range of design variables, sample stent cases were generated using Latin hypercube sampling. Objective functions were calculated for each of these by computing the two-dimensional flow using software FLUENT under the assumption of a steady, Newtonian flow considering a model stent with three struts. This was followed by Kriging to construct a response surface, which gives the relationship between the objectives and the design variables. The procedure gave nondominated fronts, which consist of optimized designs. Stents with minimum vorticity, with minimum recirculation distance, and the ones with maximum reattachment length in between struts were generated. The procedure is capable of producing the optimum set of design variables to achieve the prescribed objectives.

Experimental Investigations for Statistically Controlled Rapid Moulding Solution of Plastics Using Polyjet Printing

2010 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh ◽  
Manohar Singh Saini
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Economic Point ◽  
The Past ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate statistically controlled rapid moulding (RM) solutions for plastic components using polyjet printing (PP). Starting from the identification of component/benchmark, prototypes with three different type of plastic material were prepared, at different orientations. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the components prepared. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. Final components prepared are acceptable as per ISO standard UNI EN 20286-I (1995). This process ensures rapid production of statistically controlled pre-series technological prototypes and proof of concept at less production cost and time.

Modeling and Simulation of the Engraving Process in Different Life Stages of Small Caliber Guns

2022 ◽  
Author(s):  
Mohamed Dhouibi ◽  
Hamza Ousji ◽  
Oussama Atoui ◽  
Rachid Nasri ◽  
Marc Pirlot
Keyword(s):  
Doppler Radar ◽  
Experimental Studies ◽  
Coordinate Measuring Machine ◽  
Life Stages ◽  
Resistance Evolution ◽  
Chamber Volume ◽  
Gun Barrel ◽  
Measuring Machine ◽  
Bullet Velocity ◽  
The Relationship

Abstract Effects of erosion phenomenon on the performance of a given gun barrel have been analyzed throughout numerical and experimental studies. Mainly, qualitative observations were performed. Theoretical relations between the evolution of the inner barrel profile and the provided interior ballistics are limited. This paper focuses on the development of a numerical model to predict the engraving resistance evolution in terms of the inner barrel profile in the different weapon's life stages. Four test barrels "12.7x99mm NATO" with different chamber volumes were considered. First, a Coordinate Measuring Machine (CMM) with a contact scanning probe was used to measure the inner dimension of the guns. Second, piezoelectric sensors with a special doppler radar were considered to measure the (i) pressure and (ii) the bullet velocity in the test weapons. Finally, based on the obtained experimental results, a Finite Element (FE) analysis using the commercial software LS-DYNA was developed and validated. The obtained numerical results were used as insights to quantify the relationship between the engraving resistance and the chamber volume of small caliber guns.

Articulated Arm Length Calibration for Cantilever Coordinate Measuring Machine

2013 ◽  
Vol 333-335 ◽  
pp. 77-80 ◽  
Author(s):  
Hong Lei Ran ◽  
Shu Gui Liu ◽  
Hai Tao Zhang
Keyword(s):  
Measurement Accuracy ◽  
Small Volume ◽  
Low Cost ◽  
Coordinate Measuring Machine ◽  
Calibration Method ◽  
Measurement Range ◽  
Precision Error ◽  
Large Measurement ◽  
Measuring Machine ◽  
Error Calibration

Cantilever CMM(short for coordinate measuring machine) is non-orthogonal type one with large measurement range, small volume, light weight, low cost, but lower precision. Error calibration and compensation is an important way to improve the measurement accuracy. This paper presents a new calibration method for the length of articulated arm just using the square. Facility requirement is relatively low and it is easy to operate. Comparing with that measured by laser interferometer, this method has a relatively high accuracy, having a certain value in practical measurement.

Analysis of post-processing influence on the geometrical and dimensional accuracy of selective laser melting parts

2020 ◽  
Vol 26 (10) ◽  
pp. 1713-1722
Author(s):  
Eduardo Cuesta ◽  
Braulio J. Alvarez ◽  
Pablo Zapico ◽  
Sara Giganto
Keyword(s):  
Heat Treatment ◽  
Selective Laser Melting ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Laser Melting ◽  
Sand Blasting ◽  
Content Type ◽  
Stress Relieving ◽  
Measuring Machine

Purpose This study aims to analyze the effect of the different common post-processes on the geometrical and dimensional accuracy of selective laser melting (SLM) parts. Design/methodology/approach An artefact has been designed including cubic features formed by planar surfaces orientated according to the machine axes, covering all the X-Y area of the working space. The artefact has been analyzed both geometrically (flatness, parallelism) and dimensionally (sizes, distances) from coordinate measuring machine measurement results at three stages, namely, as-built, after sand-blasting and after stress-relieving heat treatment. Findings Results from the SLM machine used in this study lead to smaller parts than the nominal ones. This effect depends on the direction of the evaluated dimension of the parts, i.e. X, Y or Z direction and is differently affected by the sandblasting post-process (average erosion ratio of 68, 54 and 9 µm, respectively), being practically unaltered by the HT applied after. Originality/value This paper shows the influence, from a geometric and dimensional point of view, of two of the most common post-processes used after producing SLM parts, such as sand-blasting and stress-relieving heat treatment, that have not been considered in previous research.

scholarly journals Analysis of Motion Errors of Linear Guide Pair Based on Parallel Mechanism

Machines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 33
Author(s):  
Peng-Hao Hu ◽  
Ying-Jun Lei ◽  
Yang-Kai Ou
Keyword(s):  
Parallel Mechanism ◽  
Coordinate Measuring Machine ◽  
Guide Rail ◽  
Motion Error ◽  
Linear Guide ◽  
Measuring Machine ◽  
Moving Platform ◽  
Straightness Error ◽  
The Relationship ◽  
Analysis Of Motion

This paper systematically summarized the technical state of art and research results on the motion error of a linear guideway, corrected some misconceptions, and further clarified the relationship between the straightness error of the guide rail itself and the motion error of the linear stage. Moreover, a new method based on parallel mechanism is provided to study the motion errors of the linear guide pair. The basic idea is to abstract the structural relationship between the stage and the guide rail into a 4-bar parallel mechanism. Thus, the stage can be considered as a moving platform in the parallel mechanism. Its motion error analysis is also transferred to moving platform position analysis in the parallel mechanism. The straightness motion error and angular motion error of the stage can be analyzed simultaneously by using the theory of parallel mechanism. Some experiments were conducted on the linear guideway of a self-developed parallel coordinate measuring machine. The experimental data and analysis verify the feasibility and correctness of this method.

Impact of warm-up period on optical coordinate measuring machine measurement accuracy

Measurement ◽  
2021 ◽  
Vol 172 ◽  
pp. 108913
Author(s):  
Wiktor Harmatys ◽  
Adam Gąska ◽  
Piotr Gąska ◽  
Maciej Gruza ◽  
Jerzy Sładek
Keyword(s):  
Measurement Accuracy ◽  
Coordinate Measuring Machine ◽  
Warm Up ◽  
Measuring Machine

scholarly journals Analysis and Compensation of Equivalent Diameter Error of Articulated Arm Coordinate Measuring Machine

2018 ◽  
Vol 51 (1-2) ◽  
pp. 16-26 ◽  
Author(s):  
Zai Luo ◽  
Hui Liu ◽  
Dong Li ◽  
Kun Tian
Keyword(s):  
Coordinate Measuring Machine ◽  
Maximum Error ◽  
Error Reduction ◽  
Experimental Result ◽  
Average Error ◽  
Equivalent Diameter ◽  
Error Source ◽  
Measuring Device ◽  
Measuring Machine ◽  
Measuring Force

As a key part of the articulated arm coordinate measuring machine, the probe can determine the measurement accuracy. Therefore, the error source and influencing factors of the equivalent diameter of the probe are studied. First, the influence of the primary factor of the measuring force on the equivalent diameter of the probe is studied by analyzing the influence degree of its error source. Second, a mathematical model of the relationship between the equivalent diameter and the measuring force of the articulated arm coordinate measuring machine is built to compensate for the equivalent diameter error caused by the measuring force by the simulated annealing method. To illustrate the application advantage of our proposed study, a simple force-measuring device is designed based on this model. The experimental result shows that the maximum error reduction is approximately 43 µm, while the average error reduction ranges from 33 to 4.0 µm, which represents an 87.7% improvement. Overall, our proposed method can effectively compensate for the equivalent diameter error caused by the measuring force. This method can improve the accuracy of the articulated arm coordinate measuring machines on both calibration and measurement.

A Novel Method of Establishing “Datum Reference” for the Coaxiality Measurements Using the Multi-Section and Multi-Probe Gauges

2011 ◽  
Vol 317-319 ◽  
pp. 1759-1768 ◽  
Author(s):  
Lian Hu Xu ◽  
Yi Bao Yuan ◽  
Wei Ying Piao
Keyword(s):  
Mathematical Method ◽  
Measurement Accuracy ◽  
Coordinate Measuring Machine ◽  
Measurement Results ◽  
Manufacturing Errors ◽  
High Measurement ◽  
Measurement Principle ◽  
Manufacturing Accuracy ◽  
Measuring Machine ◽  
Measurement Efficiency

The electronic or pneumatic multi-section and multi-probe gauges are widely used for diameter and coaxiality measurements due to their high measurement efficiency in workshops. However, their measurement accuracy is determined mainly by the manufacturing errors of the assembly coaxiality master, therefore, how to establish coaxiality measurement datum reference is the key technology. The physical coaxiality masters are expected to be the impossible "zero error datum reference". The higher manufacturing accuracy of the masters, the more expensive for their manufacturing costs. A novel mathematical method on the basis of error separation principle was proposed in order to separate the manufacturing errors of the master. The basic principle is that the eccentric error of the coaxiality master can be expressed as the first harmonic function and the ideal zero-error datum reference could be established by the mathematical method of two sampling operations in phase difference of 180° in coaxiality master for gauge initialization. This method can be called as "mathematical datum reference" for coaxiality measurement. Experimental results indicate that the coaxiality measurement results of the multi-section and multi-probe gauge by the novel mathematical method coincide with those of the three-coordinate measuring machine and the maximum difference of both is about 0.0014 mm. The new coaxiality measurement principle can separate the datum error of the coaxiality master theoretically and can improve the coaxiality measurement accuracy greatly with the common accuracy coaxiality master.

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