Saint-Gobain High Force Grinder Fixture System

Currently, the Saint-Gobain China Grinding and Technology Center in Shanghai uses a low force grinder with an accompanying fixture system to test abrasive belts. A similar system capable of higher force grinding is desired and our team was given the task of designing the high force grinder fixture. To do this, we fully constructed original designs using SolidWorks for some parts, and for others, researched industrially available components. We analyzed each element, compared with several options, and assembled a final design based on our analyses. We compiled our work and supplied Saint-Gobain with a final concept for the high force grinder fixture

Saint-Gobain High-Force Grinder Fixture System

Currently, the Saint-Gobain China Grinding and Technology Center in Shanghai uses a low force grinder with an accompanying fixture system to test abrasive belts. A similar system capable of higher force grinding is desired and our team was given the task of designing the high force grinder fixture. To do this, we fully constructed original designs using SolidWorks for some parts, and for others, researched industrially available components. We analyzed each element, compared with several options, and assembled a final design based on our analyses. We compiled our work and supplied Saint-Gobain with a final concept for the high force grinder fixture

Desenvolvimento e validação de um método dinâmico, baseado em emissão acústica, para a caracterização em processo de rebolos convencionais

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2015A tecnologia de emissão acústica (EA) é utilizada no desenvolvimento de um método dinâmico para caracterização em processo (DICM) da topografia de rebolos convencionais. Experimentos planejados são conduzidos em uma bancada de ensaios desenvolvida, contendo um software de aquisição de sinais de EA. A bancada de ensaios e o software de aquisição possibilitam o reconhecimento de interferências entre rebolo (vs= 30 m/s) e uma ponta de diamante, na faixa de deformação elástica das ferramentas. Os sinais de EARAW adquiridos de forma on-line e originados destas interferências são utilizados como dados de entrada para técnicas de processamento de sinal e para uma Rede Neural (RN). Ambas as análises são efetuadas fora do processo de retificação, representando um método dinâmico de caracterização pós-processo (DPCM) da topografia de rebolos. Os resultados do DPCM são validados através de medições específicas nas peças retificadas (p. ex., rugosidade, microscopia, camada termicamente afetada, desvio de forma) e em réplicas extraídas da topografia do rebolo. Com base nas técnicas de processamento de sinais validadas e propostas no DPCM,implementa-se o DICM. Para este método, desenvolve-se uma bancada experimental baseada na aquisição de sinais de múltiplos transdutores,na qual sinais de EA e de força são medidos. A bancada experimental eseu software de aquisição permitem a caracterização em processo da topografia de rebolos convencionais através da extração de informações quantitativas dos sinais on-line de EARAW adquiridos durante asinterferências entre rebolo (vs= 30 m/s) e ponta de diamante na faixa de 1 µm. A informação quantificada associada com a topografia do rebolo é baseada na análise em processo dos sinais de EARAW nos domínios dotempo e frequência. Os resultados de ambas as análises são obtidos de forma instantânea em processo sem reduzir a velocidade de corte do rebolo, e sem alterar o setup do processo de retificação. Visando-se otimizar o DICM, os principais fatores que apresentam influência sobre a resposta no domínio do tempo são analisados através de uma Análise Fatorial Fracionada. O DICM é validado correlacionando-se a informação quantitativa obtida da topografia, com as análises pós-processo de sinais de força de retificação e com medições da rugosidade efetiva do rebolo (parâmetro Rts). Abstract : A Dynamic In-process Characterization Method (DICM) based on acoustic emission (AE) is developed and validated, aiming at the in-process appraisal of the topography of conventional grinding wheels. For implementing the method, planned experiments are carried out by firstly developing an AE-based experimental rig with its particular software application. This enables to recognize shallow interferences amid the grinding wheel (vs= 30 m/s) and a diamond tip, in the elasticdeformation range of the tools. The on-line acquired AERAW signalsderived from such interferences are used as input data for signal processing techniques and a Neural Network (NN). Both analyses areimplemented out of the grinding process and therefore consist in aDynamic Post-process Characterization Method (DPCM). The DPCM´sresults are validated by measuring both the ground workpieces (i.e. roughness, microscopy, thermally affected layer and form deviation) and the replicas extracted from the grinding wheel´s topography. Based on the validated signal processing techniques proposed by the DPCM, the DICM is implemented. This is achieved by employing a transducer-fused experimental rig in which both AE and force signals are measured. The experimental rig and its developed software application enable in-process characterization of the topography of the conventional grinding wheel by extracting quantitative information from the AERAW signalswhich are on-line acquired during the interferences between the grinding wheel (vs= 30 m/s) and a diamond tip in a range of 1 µm. The quantified information associated with the grinding wheel´s topography is based on both a time domain and a frequency domain in-process analysis. Theresulting outputs from these analyses are obtained instantaneously in-process by neither interrupting the grinding process nor decelerating the grinding wheel´s cutting speed. In order to define an optimizedexperimental condition to assess the grinding wheel´s topography, the main factors which present direct influence on the time domain output were analyzed by using a Fractional Factorial Analysis. The DICM is validated by correlating the obtained quantified information from thegrinding wheel´s topography with both the post-process evaluation of the grinding cutting force and the post-process measurements of the effective roughness of the grinding wheel (parameter Rts)

Advances and Trends in Non-conventional, Abrasive and Precision Machining

The work included in this book pertains to advanced abrasive and nonconventional machining processes. These processes are at the forefront of modern technology, with significant practical significance. Their importance is also made clear by the case studies that are included in the research that is presented in the book, pertaining to important materials and high-end applications. However, the particularities of these manufacturing processes need to be further investigated and the processes themselves need to be optimized. This is conducted in the presented works with significant experimental and modeling work, incorporating modern tools of analysis and measurements

Controller Design for Active Vibration Damping with Inertial Actuators

In the machining industry, there is a constant need to improve productivity while maintaining required dimensional tolerances and surface quality. The self-excited vibration called chatter is one of the main factors limiting machining productivity. Chatter produces unstable cutting conditions during machining and unstable forces will damage and shorten the life of the machine tool. It can also damage the cutting tool, machining components as well as produce a poor surface finish on the workpiece. Researchers have developed various chatter suppression techniques such as changing process parameters, spindle speeds, and using passive dampers. However, many of these methods are not very robust to changing dynamics in the machine tool due to changing machine positioning, cutting setups, etc. Active vibration damping with a force actuator is a robust method of adding damping by due to its bandwidth and variable controller gains. However, the commissioning of the controller design for the actuators is not trivial and requires significant manual tuning to reach optimal productivity. The research presented in this thesis aims to simplify and automate the controller design process for force actuators. A frequency domain, sensitivity based automatic controller tuning method for force actuators has been developed. This method uses the measured actuator dynamics and open-loop system dynamics to develop a prediction tool for closed-loop responses without needing to have the complete system model (model free). By monitoring the predicted closed-loop response of various virtually designed controllers, an optimal controller is found amongst the candidate parameter values. The stability of the system and actuator is monitored during the search to ensure that the system is stable throughout its bandwidth that the actuator does not become saturated. The controller is then experimentally tested to ensure that the predicted output is the same as the real output. In cases where the system has several vibration modes that are in counter-phase and close in frequency, the model-free approach does not perform well. A more complex model-based control law has also been developed and implemented. The method automatically identifies a transfer function model for the measured open-loop system dynamics and synthesizes mixed-sensitivity optimization based controller to damp out the modes in counter-phase. In order to verify that the model-based controllers can reduce vibration modes in counter-phase, a small-scale experimental setup was developed to mimic machine tools with vibration modes in counter-phase. A flexure was designed and fabricated. A shaker from Modal Shop is used as an active damping actuator to reduce the flexure’s vibration modes. It was concluded that while the model-based controller synthesis techniques were able to damp the vibration modes in counter phase, the flexure was too simplistic and the model-free controller was able to achieve similar results

Hybrid Bulk Metal Components

In recent years, the requirements for technical components have steadily been increasing. This development is intensified by the desire for products with a lower weight, smaller size, and extended functionality, but also with a higher resistance against specific stresses. Mono-material components, which are produced by established processes, feature limited properties according to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be reached by combining different materials in a hybrid metal component. In this way, components with tailored properties can be manufactured that meet the locally varying requirements. Through the local use of different materials within a component, for example, the weight or the use of expensive alloying elements can be reduced. The aim of this Special Issue is to cover the recent progress and new developments regarding all aspects of hybrid bulk metal components. This includes fundamental questions regarding the joining, forming, finishing, simulation, and testing of hybrid metal parts