Artigos Técnicos

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Volumetric Error Identification for CNC Machine Tool Based on Multi-body System and Vector Diagonal Measurement

To reduce the influence of the geometric error on machining precision of CNC machine, a new method based on multi-body system theory and the laser sequential step diagonal vector measurement method to distinguish the geometric errors of CNC machine tool was presented. Firstly geometric errors modelling of CNC machine tool based on multi-body system theory was established. Then laser sequential step diagonal vector measurement method was introduced. Finally comparison experiments of the directly traditional method and the laser vector diagonal measurement method were done, besides, error compensation experiment of CNC machine tool was done. The results show that the new method combined multi-body system theory and laser sequential step diagonal vector measurement method is feasible to distinguish the geometric errors and after compensation machine accuracy is improved by 63%.

Geometric and force errors compensation in a 3-axis CNC milling machine

This paper proposes a new off line error compensation model by taking into accounting of geometric and cutting force induced errors in a 3-axis CNC milling machine. Geometric error of a 3-axis milling machine composes of 21 components, which can be measured by laser interferometer within the working volume. Geometric error estimation determined by back-propagation neural network is proposed and used separately in the geometric error compensation model. Likewise, cutting force induced error estimation by back-propagation neural network determined based on a flat end mill behavior observation is proposed and used separately in the cutting force induced error compensation model. Various experiments over a wide range of cutting conditions are carried out to investigate cutting force and machine error relation. Finally, the combination of geometric and cutting force induced errors is modeled by the combined back-propagation neural network. This unique model is used to compensate both geometric and cutting force induced errors simultaneously by a single model. Experimental tests have been carried out in order to validate the performance of geometric and cutting force induced errors compensation model.

Simplifying Volumetric Error Correction

Characterizing the errors in the entire working volume of a CNC machine tool can improve how well parts made on it comply to their design drawings. Characterizing the errors of a CMM can reduce its uncertainty of measurement, improving its measurement accuracy. Entry of the errormap data as correction factors essentially linearizes stage motion. Although full working volume characterization is a worthy goal, the process for errormapping these systems has been lengthy and tedious, requiring setup and analysis by skilled technicians.Taking a machine tool out of production for 1 ½ – 2 days to perform volumetric calibration is not very attractive to any shop.

Real Time Compensation of Machining Errors for Machine Tools NC based on Systematic Dispersion

Manufacturing tolerancing is intended to determine the intermediate geometrical and dimensional states of the part during its manufacturing process. These manufacturing dimensions also serve to satisfy not only the functional requirements given in the definition drawing, but also the manufacturing constraints, for example geometrical defects of the machine, vibration and the wear of the cutting tool. In this paper, an experimental study on the influence of the wear of the cutting tool (systematic dispersions) is explored. This study was carried out on three stages .The first stage allows machining without elimination of dispersions (random, systematic) so the tolerances of manufacture according to total dispersions. In the second stage, the results of the first stage are filtered in such way to obtain the tolerances according to random dispersions. Finally, from the two previous stages, the systematic dispersions are generated. The objective of this study is to model by the least squares method the error of manufacture based on systematic dispersion. Finally, an approach of optimization of the manufacturing tolerances was developed for machining on a CNC machine tool.

AFM Technology GmbH - Accuracy for Machines

CIRP Annals - Mannufacturing Technology

Laser Tracker Calibration - Testing the Angle Measurement System

Physics experiments at the SLAC National Accelerator Laboratory (SLAC) usually require high accuracy positioning, e. g. 100 µm over a distance of 150 m or 25 µm in a 10 x 10 x 3 meter volume. Laser tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. The accu-racy of these measurements is related to the manufacturing tolerances of various individual components, the resolutions of measurement systems, the overall precision of the assembly, and how well imperfections can be modeled.

Técnicas de Calibração de Robôs

This work presents a comparison of four different methodologies for identifying the calibration parameters of a Motoman P-8 robot located at Sandia National Laboratories. This robot is a 6-dof, all revolute robot with one of the most popular configurations. The robot was modeled using a modified Denavit and Hartenberg technique that utilized Hayati’s notation to represent transformations between nearly parallel joint axes. The four identification techniques considered were the Steepest Gradient method, the Monte Carlo method, the Guided Evolutionary Simulated Annealing method, and the Circle-Point method. These four techniques were evaluated against four different data sets.

Requisito de Inspeção de Válvulas de Bloqueio

Este documento estabelece os requisitos de inspeção a serem observados pelo fornecedor em atendimento aos PCS’s e demais documentações técnicas contratuais.

Failure Mode & Effects Analysis

Handbook Supplement for Machinery - Ford Production System

Potential Failure Mode and Effects Analysis

OEE

Utilização do Indicador de Eficácia Global de Equipamentos (OEE) na Gestão de Melhoria Contínua do Sistema de Manufatura - Um Estudo de Caso

Calculo para Frequência de calibração