Investigation of feeding devices and development of design considerations for a new feeder for micro-sheet forming

Recent review in micro-forming research and technological development suggested that the trend of the development is more focused on the manufacturing processes, machines and tooling, and efforts on the methods and systems for integrated precision material handling are insufficient. Most of the developed micro-forming machines were based on standalone concepts which do not support efficient integration to make them fully automated and integrated. At present, material feeding in micro-forming is not of sufficient precision and reliability for high throughput manufacturing applications. Precise feeding is necessary to ensure that micro-parts can be produced with sufficient accuracy, especially in multi-stage forming, while high-speed feeding is a must to meet the production-rate requirements. Therefore, design of a new high-precision and high-speed feeder for micro-forming is proposed. Several possible approaches are examined with a view to establishing feasible concepts. Based on the investigation, several concepts for thin sheet-metal feeding for micro-forming are generated, they being argued and assessed with applicable loads and forces analysis. These form a basis of designing a new feeder

Temporary fixing systems for applications in Microrobotics.

International audienceThis paper focuses on temporary fixing systems for microrobotics. Several solutions from the art are presented and compared : solutions based on mechanical bending, electromagnetic elements, electrostatic forces, glues, polymers or Van der Waals forces. From this analysis, we designed and developed a new system based on thermal glue (that permits to exchange the tip part of a microgripper) for microassembly stations. This system brings a high flexibility and compactness for microrobotic applications

Data representation for the control of full-automated microfactories.

International audienceThe increase greater than ever in the developments of microproducts leads us to consider the design of an automatic, flexible, reconfigurable and upgradeable microfactory. Thus defined, the microfactory has the ability to implement an infrastructure of automated manufacture in small or average batches, and will be able to prove the feasibility of automated production in greater quantity. Two main difficulties have been identified. First, the operator in charge of the production setting has accessibility problem in the microworld. Second, the permanent adaptation of the production system to the variations of the intrinsic parameters of the microworld. Consequently, such a concept of microfactory must assist the operator by the capitalization of last experiments and the restitution of acquired know-how. Taking into account the importance and diversity of information, our approach consists in defining all this technical information system. Our method went on a modeling of the microfactory under UML, using the “use-cases” and “classes” diagrams. The technical information system resulting from our work is the spinal cord of the microfactory, it will constitute the base of the piloting structure

Microforce sensor for microbiological applications based on a floating-magnetic principle.

International audienceIn this paper, we present the design of a new magentic nano and microforce sensor for microbiological applications. The sensing part of the sensor presents a naturally stable six degrees of freedom equilibrium state using the combination of upthrust buoyancy and magnetic force. The sensor allows force measurement without deformation of the sensing element using a feedback control loop and is able to measure the components, in the horizontal plan, of the external force applied. The measurement range varies between around ± 100 µN with a resolution of 20 nN and a linear output. The mechanical stiffness of the passive system is about 0.018 N.m−1(same order of magnitude than an AFM micro-cantilever). A complete static study and experimental validation of the used principle are presented in this paper

Analysis of the trade-off between resolution and bandwidth for a nanoforce sensor based on diamagnetic levitation.

International audienceNanoforce sensors based on passive diamagnetic levitation with a macroscopic seismic mass are a possible alternative to classical Atomic Force Microscopes when theforce bandwidth to be measured is limited to a few Hertz.When an external unknown force is applied to the levitating seismic mass, this one acts as a transducer that converts this unknown input into a displacement that is the measured output signal. Because the inertia effect due to the mass of such macroscopic transducers cannot be neglected for timevarying force measurement, it is necessary to deconvolve the displacement to correctly estimate the unknown input force.A deconvolution approach based on a Kalman filter and controlled by a scalar parameter has been recently proposed.The adjustement of this parameter leads to a trade-off that is analysed in this paper in term of resolution and bandwidth of the estimated force. Associated tools to help the end-user to set this parameter are also described

Nanoforce estimation with Kalman filtering applied to a force sensor based on diamagnetic levitation.

International audienceNano force sensors based on passive diamagnetic levitation with a macroscopic seismic mass are a possible alternative to classical Atomic Force Microscopes when the force bandwidth to be measured is limited to a few Hertz. When an external unknown force is applied to the levitating seismic mass, this one acts as a transducer that converts this unknown input into a displacement that is the measured output signal. Because the little damped and long transient response of this kind of macroscopic transducer can not be neglected, it is then necessary to deconvolve the output to correctly estimate the unknown input force. The deconvolution approach proposed in this article is based on a Kalman filter that use an uncertain a priori model to represent the unknown nanoforce to be estimated. The main advantage of this approach is that the end-user can directly control the unavoidable trade-off that exists between the wished resolution on the estimatedforce and the response time of the estimation

Manipulation aux échelles microscopiques.

National audienceLa manipulation robotique aux échelles microscopiques représente un enjeu majeur pour le développement des techniques biologiques et pour l'avènement de produits hautement miniaturisés réalisés par micro-assemblage. La miniaturisation d'un système de manipulation est confrontée à plusieurs ruptures de type physique ou technique, comme par exemple la prédominance des forces d'adhésion sur le comportement des micro-objets ou le changement des techniques de fabrication influençant fortement les méthodes de conception des microrobots. L'objet de l'étude de la manipulation aux échelles microscopiques porte sur la recherche de méthodes robotiques adaptées à ce nouveau paradigme : le micromonde. La compréhension et la modélisation de ce micromonde sont un corollaire essentiel à l'étude de stratégies robotiques adaptées. Basées sur cette modélisation, de nouvelles stratégies de manipulation sont étudiées en prenant en compte les comportements particuliers des micro-objets tel que les collages sur les organes terminaux. La mise en oeuvre de ces stratégies de manipulation nécessite une structure robotique complète incluant des systèmes de perception et de contrôle de l'environnement. La commande de l'ensemble soit par téléopération avec retour haptique soit en cycle automatique est enfin également un enjeu scientifique

A review on micro-manufacturing, microforming and their key issues

Micro-manufacturing has received good attention globally in terms of its manufacturing methods/processes. One of the most popular micro-manufacturing processes is micro-forming. Many efforts have been focused on micro-forming, mainly on the micro-stamping process due to the process itself contributing numerous products, especially in its conventional macro-process. Most every-day products are made by this process. Although there were efforts made to realize micro-forming for industrial application, the technology itself was seen as being insufficiently mature. Much development work needed to be done, specifically to develop a fully-automated high-volume production micro-forming machine, which is reliable and at all times ready for operation in terms of it processes, tooling, and material-handling to ensure the successful production of micro-products. The paper addresses key issues encountered by researchers worldwide on both micro-manufacturing, specifically micro-forming

Flexible micro-assembly system equiped with an automated tool changer.

International audienceThis paper deals with the design, fabrication and experimental validation of several modules of a micro-assembly system. On one hand, a microgripper is integrated in a four degrees of freedom system. On the other hand, a tool changer is designed. It enables to exchange automatically the tip part of the microgripper and then dedicated tools can be used to achieve specific tasks. The principle of this tool changer relies on a thermal glue whose phase (liquid or solid) is controlled by heat generators. This system is based on the modeling of thermal phenomena in the tools during a cycle of tool exchange. A compliant system is added to limit micromanipulation forces applied during assembly tasks like insertions. Finally, the successful assembly of several microcomponents is detailed, highlighting the capabilities and benefits of the whole system

Modeling and experimentation of a passive low frequency nanoforce sensor based on diamagnetic levitation.

International audienceThis paper is focused on the study of a new low frequency micro and nanoforce sensor based on diamagnetic levitation. The force sensitive part is a tencentimeter long macroscopic capillary tube used as a levitating seismic mass. This tube presents a naturally stable equilibrium state with six degrees of freedom thanks to the combination of diamagnetic repulsive and magnetic attractive forces. It is only used as a one-direction force sensing device along its longitudinal axis. This force sensor is passive. The force measurement is based on the displacement of the capillary tube and in steady-state this displacement is proportional to the force. This sensor is characterized by an under-damped second-order linear force-displacement dynamic which remains linear on several hundred micrometers and can thus measure a wide range of microforces. Because of the magnetic springs con guration used, the capillary tube presents a horizontal mechanical sti ness that can be adjusted between 0.01 and 0.03 N/m (similar to the sti ness of a thin AFM cantilever). The measurement range typically varies between 50 N. Bandwidth is 4 Hz. The resolution depends on the sensor used to measure the capillary tube displacement and on noises induced by environmental conditions (ground and air vibrations). The resolution typically reached with a STIL confocal chromatic sensor is 5 nN inside a test chamber located on a anti-vibration table. This study is illustrated by a pull-off force measurement