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Towards the first generation micro bulk forming system
Abstract
The industrial demand for micro mechanical components has surged in the later years with the constant introduction of more integrated products. The micro bulk forming process holds a promising pledge of delivering high quality micro mechanical components at low cost and high production rates. This work describes a number of prototype system units, which collectively form a desktop sized micro forming production system. The system includes a billet preparation module, an integrated transfer system, a temperature controlled forming tool, including process simulation, and a dedicated micro forming press. The system is demonstrated on an advanced micro forming case where a dental component is formed in medical grade Titanium.
... For bio-fabrication, investigations are conducted to produce natural (e.g., bones and tissues) and artificial (e.g., platinum group materials) biomaterials that can be used for Fig. 1. Biomanufacturing defined from two perspectives: 1) mechanical: biomechatronics [1] and bio-fabrication [4][5]; 2) biomedical: gene and cell therapies (image from Penn Medicine). arthroscopy, oncology, and dental treatment [2]. ...
... arthroscopy, oncology, and dental treatment [2]. For example, dental implants are forged with elevated temperatures [4]. Pressures are monitored to ensure the quality and reliability of the produced implant. ...
Technical advances in 3D metrology bring the increasing availability of imaging data, which are critical to quality inspection and process improvement. Dealing with 3D imaging data has become a general problem facing both traditional and next-generation innovation practices in biotechnology. Traditional methodologies in statistical quality control focus on key characteristics of the product, and are limited in the ability to model spatiotemporal patterns in imaging streams. This paper presents a dynamic network methodology for monitoring and control of high-dimensional imaging streams. The developed methodology is implemented and evaluated for process monitoring of living cells during the synthesis of bio-products.
... Using sticking forces to hold and transfer the microspecimens, Arentoft et al. [14] developed an integrated twostep system for microforming. The process has the capability of production of micro-parts with reasonable production rate, using billets as the feed for the process. ...
... It suggests that there is a copper-copper contact inside the die (due to galling) during pin forming which makes the friction condition severe. This challenge has been reported before [14,26] which needs more investigations to be understood. ...
Although there is considerable published literature on micro-metal forming processes, there is still a lack of research towards implementing these processes commercially. Some of the challenges are handling of micro-parts and process intermittency. This work demonstrates the feasibility of producing symmetric micro-parts using a progressive forming set-up. Such a progressive forming process alleviates the challenges in handling and removal of micro-parts. Micro-pins with diameters of 0.3, 0.5, and 0.8 mm were successfully manufactured without defects. Experimental observations together with process simulation results showed that this process has three main stages: (1) indentation at the very beginning, (2) upsetting, and (3) extrusion predominantly occurring at the very end stage of the stroke. The bulk of the pin forming occurs at the end stroke of the process (extrusion stage). The effects of punch/pin diameter ratio on the pin aspect ratio and the maximum forming load were also investigated. In addition, the finite element results also revealed that a hybrid friction model was required to be implemented for better fit with experimental results as compared to the shear and Coulomb friction models.
... Pengembangan mesin micro-press yang pernah dilakukan oleh peneliti lain diantaranya adalah Groche, et al. [15] membuat prototipe mesin micro-forming dengan kapasitas maksimum 20 kN dan kecepatan maksimum 1200 spm (stroke/minutes). Selain itu, Flexible µ-Forming berkapasitas 5,3 kN pernah dikembangkan oleh Y. Qin, et al. [16] yang dilengkapi dengan alat ukur gaya proses beresolusi sebesar 0,1 N. Presz et al. [17] mengembangkan mesin micro-forming dengan kapasitas 5 kN dengan penggerak piezoelectric, sementara Arentoft, et al. [18] menggunakan aktuator servo motor untuk mesin micro-forming nya berkapasitas 50 kN. Sedangkan, Jie Xu, et al. [1] mengembangkan mesin micro-forming dengan kapasitas 8,8 kN dengan kecepatan stroke maksimum 1,1 m/s, dan mampu beroperasi pada kecepatan minimum sebesar 5 µm/s dengan resolusi posisi 0,12 µm. ...
The increasing application of micro electro mechanical systems technology on daily life devices increases the need for micro components. Furthermore, it must be supported by reliable fabrication technology to produce micro-sized products. One of these technologies is micro-sheet metal forming, which is a forming technology from sheet metal with 10-300µm thickness. The development of this technology requires a special press machine that is used in the scope of micro-scale work, named micro-press. Micro-press is still rare due to it was used for individual experiment purposes. Thus, it is necessary to develop the micro-press to support research and manufacturing of micro-part. In this study, the design of a micro-press is intended to accommodate the miniaturization problems and to be easy in fabrication and re-fabrication. Then, the micro-press will contribute to fulfill the micro-parts need. By using the VDI 2222 design method, the design of a 5kN micro-press machine with a servo motor drive is obtained, and validation of construction strength was carried out with the help of the appropriate CAE software. The results of the design validation show that the construction of the micro-press machine is quite strong. The selected component has a strength specification that is greater than required, and the maximum stress that occurs in the frame, which is 80.096 N/mm2, is still very lower than the allowable stress on the SPHC material. The magnitude of the resultant displacement shows a fairly small value, i.e. 0.178 mm.
... For this reason, scientists are working on solutions to improve the handling of the micro parts during multi-stage forming. Arentoft et al. have developed an inline part-transfer system in a multi-stage bulk micro forming process, which enables a production rate of 50 parts per minute [9]. Hirota [10] has investigated the direct extrusion of metallic micro parts from sheet metal in order to simplify the handling considerably. ...
Product miniaturisation and functional integration are currently global trends to save weight, space, materials and costs. This leads to an increasing demand for metallic micro components. Thus, the development of appropriate production technologies is in the focus of current research activities. Due to its efficiency, accuracy and short cycle times, microforming at room temperature offers the potential to meet the steadily increasing demand. During microforming, size effects occur which negatively affect the part quality, process stability, tool life and handling. Within this contribution, a multi-stage bulk microforming process from sheet metal is investigated for the materials Cu-OFE and AA6014 with regard to the basic feasibility and the occurrence of size effects. The results reveal that the process chain is basically suitable to produce metallic micro parts with a high repeatability. Size effects are identified during the process. Since several studies postulate that size effects can be minimised by scaling down the metallic grain structure, the grain size of the aluminium material AA6014-W is scaled down to less than one micrometre by using an accumulative roll bonding process (ARB). Subsequently, the effects of the ultrafine grain (UFG) structure on the forming process are analysed. It could be shown that a strengthened material state increases the material utilization. Furthermore, too soft materials can cause damage on the part during ejection. The occurring size effects cannot be eliminated by reducing the grain size.
... Although these terminologies are widely used, their denominations may misleadingly induce to think of a distinction between the two categories purely based on the initial geometry of the material. However, bulk forming can also be done with sheet metals [1] and some micro-processes are also part of this category [2]. The differentiation is instead based on the kind of plastic deformation occurring during the process. ...
The family of bulk forming technologies comprises processes characterised by a complex three-dimensional stress and strain state. Besides shape and material properties, also residual stresses are modified during a bulk metal forming process. The state of residual stresses affects important properties, like fatigue behaviour and corrosion resistance. An adjustment of the residual stresses is possible through subsequent process steps such as heat treatments or mechanical surface modification technologies, like shot peening and deep rolling. However, these additional manufacturing steps involve supplementary costs, longer manufacturing times and harmful effects on the product quality. Therefore, an optimized strategy consists in a targeted introduction of residual stresses during the forming processes. To enable this approach, a fundamental understanding of the underlying mechanisms of residual stress generation in dependence of the forming parameters is necessary. The current state of the art is reviewed in this paper. Strategies for the manipulation of the residual stresses in different bulk forming processes are classified according to the underlying principles of process modification.
... Main prime mover is linear motor with maximum slide speed: 110 m/s 2 . Flexible -Forming with capacity of 5.3 kN was developed by Y. Qin et al. [4] with load-measurement resolution of sebesar 0.1 N. Presz et al. [5] and Arentoft et al. [6] developed micro-forming machine with capacity of 5 kN and 50 kN using different actuator. Prescz used piezoelectric, while Arentoft used servo motor. ...
The need of micro part become increasingly popular which make increase of the need of prodution technology with high accuracy, productivity, efficiency, and reliability.Metal forming technology offers the solution to answer the challenge. High produtivity, zero material losses, good mechanical properties of product, and tight tolerance is able to achieve by micro forming technology. This thing make metal-forming fit for mass production based on near net shape technology concept it offered.Miniaturized effect phenomena which was not simple on micro-scale manufacturing process, demand high accuracy level from all aspect of micro-manufacturing process, which are material, tool, machinery and process. Therefore, characteristic of micro-forming machine become important in defining reliability of micro-forming system. Micro-forming machine under investigation was 5 kN m-Forming Machine developed in Manufacturing Laboratory, Department of Mechanical Engineering, Universitas Indonesia. Modification to the machine made changes on machine characteristic. Therefore, it need characterization of the machine by measuring its geometric measurement and linear movement. The research revealed that deviation caused by imperfection of geometry of assembled machine component shown good results. Testing of linear movement of machine in one cycle show the range of deviation was 0.024 mm with smallest deviation was -0.0135 mm while the biggest one was 0.0105 mm. The value of deviation was below etimated value which estimated from mathematical analisys of backlash. The results of machine linear movement also gave reccomendation of effective path of 5 kN m-Forming Machine, which is on path along 30 mm to 40 mm, from point A which had been decided before.
... These challenges led to the development of new micro manufacturing and assembly concepts with adopted and integrated machine designs [6,7]. A complete micro bulk forming system was presented and analyzed by Arentoft et al. [8]. They considered not only the forming system itself but also all process steps, including handling. ...
For simplified processing and the enhancement of output rate in multi-stage production, micro parts are handled as linked parts. This contribution discusses handling specific challenges in production based on an exemplary process chain. The examined linked parts consist of spherical elements linked by wire material. Hence, the diameter varies between the wire and part. Nevertheless, the linked parts must be handled accurately. The feed system is an important component too, but special focus is given to the guides in this present study. They must adapt to the diameters of both the parts and the linking wires. Two alternative variants of adaptive guides are presented and investigated under the aspects of precise radial guiding, vibration isolation, damping behavior and friction force.
... They revealed that the moderate temperature could significantly improve the homogeneity of material flow and reduce the scatter of process performance without losing the benefits of cold meso/micro-forming. In addition, Arentoft et al. [18][19][20] developed a microforming system with the controlled temperature up to 450°C, and conducted warm microforming of magnesium and aluminum alloys for fabrication of microparts for biomedical applications. Kim et al. [21] evaluated the microformability of ultrafine-grained magnesium alloy. ...
With the increasing demand for meso/micro-scaled medical products made of biocompatible materials, thermal-aided mesoforming is proposed to improve material formability and homogenize flow behavior of materials that are difficult to deform at room temperature. However, the unique material deformation behavior and the interactive effects of material microstructure and deformation temperature on forming quality of the fabricated micropart remain unknown. This study thus aims at addressing this issue in thermal mesoforming in terms of deformation load, material flow, microstructural evolution, dimensional accuracy, and defect formation. Accordingly, the fabrication of a titanium dental abutment by one-stroke mesoforming at elevated temperature is conducted and explored. The characteristic and quality of the mesoformed part are extensively examined. The surface grains on the square extrudate undergo severe deformation and generate an equiaxed structure, reflecting that mesoforming at elevated temperature facilitates the homogenization of material flow without coarsening grain size. In addition, the dimensional accuracy, surface quality and the sizes of burr and flash are associated with the initial grain size of pure titanium, and the surface finish is improved by using fine-grained titanium. The fine-grained material is thus desirable for achieving the optimal surface quality in the thermal-aided mesoformed parts.
... To realize the batch production of microparts using microforming, the difficulty in handling, transporting, stripping and positioning of billet, preform, semi-finished or final part must be overcome [12,13]. One way of handling and positioning microparts is using robot and advanced gripper system, which is proven to be complicated, tailor-made, less efficient and costly [14]. To address the handling, transportation and ejection issues in microforming, Hirota [15] put forward a new method to fabricate micro billet via extruding the sheet metal in thickness direction, and studied the effect of constraint condition on the height of the extruded billet. ...
With the increasing demand for the quality and quantity of miniaturized parts, fabrication of microparts directly using sheet metals is proven to be promising and efficient for mass production. In this process, however, there are many unknowns in terms of size effect and its affected fracture and deformation behavior. This study is thus aimed at investigating the micromechanical damage and deformation behavior in progressive microforming and establishing a systematic knowledge to support the microformed part design, process configuration and tooling design. In detail, a micro cylindrical part is fabricated via shearing process and a multi-level flanged part is produced via progressive micro extrusion and blanking. To explore the effect of material microstructure on the deformation behavior, ductile fracture and the product quality of microformed part, the original sheet metals are annealed under different temperatures. To realize the microforming process, a progressive microforming system is developed and its characteristics are investigated. The effect of grain size on dimensional accuracy, microstructure evolution and fracture behavior in microforming is also studied. The ductile fracture and its induced defects are identified and the damage accumulation is predicted. In the end, the validity and applicability of different fracture criteria in microforming is discussed.
... Previous study indicated a micro forming press included a cropping tool for billet preparation, and a micro forming press with an integrated transfer system [5]. The gripping principle of transport device was fabricated on the basis of surface tension force. ...
Multi-step micro bulk forming is characterized by complex processes and high precision requirements. Several process parameters influence on accuracy of micro forged parts where small tolerances in the order of few μm are in demand. The paper introduces a high performance transfer press for micro cold bulk forming. A methodology for selection of linear motors on the bases of the process parameters was obtained. In order to examine the effectiveness of the machine, specific geometry was investigated for production. Kinematic parameters were found for a production rate of 200 strokes per minute. A forged part with three different diameters in height was produced in a two-stage forming process using the introduced transfer press.
... Eriksson et al. [12] discussed the main hypothesis related to the use of industrial robots as a key module in manipulation of micro-mechanical components. Arentoft et al. [13] developed a twostep microforming system integrated with an inline transfer system, which was capable of accurately feeding and transferring billets and deformed parts. Furthermore, Mahshid et al. [14] analyzed the positioning precision of actuator and gripper in a handling system for multi-step micro bulk forming using laser interferometry. ...
With the significantly increasing demand on a large scale of miniaturized parts, the fabrication of micro-parts by directly using sheet metal is proven to be a promising and efficient micro-manufacturing process. In this process chain, shearing is used to pre-pierce hole or blank cylindrical part. In this research, the material deformation behavior and the fracture effect in shearing are extensively studied and it is revealed that they have a significant effect on the subsequent operations and the quality of the fabricated parts. In addition, the influence of forming conditions on deformation behavior, fractured surface quality and dimensional accuracy in shearing operation are systematically investigated. The interactive effects of multi-factors including grain size, lubricated condition and shear velocity on the quality of both the blanked part and the pierced hole are discussed. It is revealed that the forming quality deteriorates with the increase of grain size and shear velocity. High viscosity lubricant leads to low deformation load and small work hardening as well as good surface finish. The rag at the pierced hole edge and the surface breakages on the blanked part exist under high shear velocity, and the shear velocity should be controlled within a certain limit to balance the productivity and surface quality. Furthermore, the ultimate shear strength, billet diameter and burr height have the extreme values when the initial grain size equals to the punch-die clearance. Therefore, the deformation behavior and the product quality in micro shearing process is affected by the interactive effect of material state, die dimension, lubricated condition and shear velocity.
With the rapid development of micro-electromechanical systems (MEMS), micro/nanoscale fabrication of 3D metallic structures with complex structures and multifunctions is becoming more and more important due to the recent trend of product miniaturization. As a promising micromanufacturing approach based on plastic deformation, micro/nanoforming shows the attractive advantages of high productivity, low cost, near-net-shape, and excellent mechanical properties, compared with other non-silicon-based micromanufacturing technologies. However, micro/nanoforming is far less established due to the so-called size effects in terms of materials models, process laws, tooling design, etc. The understanding of basic issues on micro/nanoforming is not yet mature, and it is currently a topic of rigorous investigation. Here, a systematic review on the micro/nanoforming processes of 3D structures with multifunctional properties is presented, wherein also a critical examination of the interplay between relevant length scales and size effects affecting the structural integrity of micro/mesoscale metallic systems is also provided. Finally, the challenges of micro/nanoscale fabrication are proposed, including the development trends of new micro/nanoforming processes, multiple field coupling effects, and theoretical modeling at the trans-scale.
This contribution deals with interactions between feed system and process in the production of preforms as linked parts, which is the first step of a multi-stage process chain for cold forming of micro parts. Due to the interconnection of the parts, the feed system is not only used for part transport, but also for the positioning during the generation of the preforms by laser rod melting. Thereby, the influence of the feed system on the production is more significant. Absorbed laser energy melts a wire, so that a melt pool is formed. While the wire is fixed on one side, the other side is fed into the melt pool whose volume increases. The production can be divided in the steps of preheating, active melting, solidification and transportation. The positioning takes place in parallel to the melting. Until now, the increase of the output rate was based especially on the consideration of the melting process and higher feed velocities. In this contribution, the interactions between feed and process are analyzed with the goal of further increasing the output rate. For that reason, the positioning behavior and its influence on the geometry of the produced preforms are analyzed. Finally, a method is presented, which unites the steps of transportation, preheating and melting. It is shown, that by a favorable coordination of the individual process steps, a further increase of the output rate is achievable without significantly worsening part quality.
Product miniaturization is an emerging trend for facilitating product usage, enabling unique product functions to be implemented in micro-scaled geometries and features, and further reducing product weight and volume. Recently, a demand for microparts increased significantly in many industry clusters. Development of the advanced micromanufacturing technologies for fabrication of such microparts has thus become a critical issue. Microforming, which offers attractive characteristics including high productivity, low cost and good quality of the formed parts, provides a promising approach to fabricating metallic microparts. In the last two decades, a lot of effort has been made to the researches on size effect related deformation behaviors in microforming process and the development of the process. Having a panorama of these researches is necessary to support micropart design and development via microforming, and further advance this micromanufacturing process. In this paper, an intensive review on the latest development of microforming technologies is presented. First of all, the paper is focused on the review of the size effect-affected deformation behaviors and the mechanisms of the changes of flow stress, flow behavior, fracture behavior, elastic recovery, tooling–workpiece interfacial friction and the surface finish of the formed parts. The state-of-the-art microforming processes, including micro deep drawing, microembossing, micropunching, microcoining, microextrusion, microheading, and micro progressive forming are then presented. Finally, some research issues from the implementation of mass production perspective are also discussed.
Conventional single stage cold upsetting processes are limited to upset ratios 2 in micro range due to size effects. To still benefit from the advantages of upsetting, an alternative process chain called "laser rod end melting" is presented in this work. Prior to cold forming, the wrought material is locally melted by a laser beam whilst the surface tension causes the melt to form spherically, called "preform" . Experimental investigations show that the master forming stage allows geometrical tolerance IT9 in diameter of preform. An analytical, non-adiabatic model is set up describing very well the master forming stage in terms of pulse energy, deflection velocity and preform diameter. The dendritic grain structure of preforms does not show any deficits when forming is carried out in cone-shaped dies and it is possible to replicate surface structures as small as 0,001 mm. Hence, this work shows that the laser rod end melting process is well suitable to significantly shorten multi-stage cold forming operations.
This keynote paper addresses the manufacturing of high-precision components with micro-scale features, and the associated process chain considerations. Three workpiece classifications as well as a micro-production process chain (MPPC) model are defined. A review of capabilities and advances in micro-manufacturing technologies, metrology, and equipment demonstrates increased versatility across varied applications, while also highlighting limitations. Challenges in the development of process chains are presented using results of the MPPC program of the Collaborative Working Group on Micro-Production Engineering. Finally, a guide for machining high-precision components with micro-scale features in process chains is given with respect to machine tools, tools, technology and environmental conditions.
With the global trend of product miniaturization, the market demands for microparts are increasing tremendously and state-of-the-art micromanufacturing processes for fabrication of microparts thus become critical. Microforming, as one of the micromanufacuring processes, provides a promising approach to fabricating metallic microparts, such as connector pin, miniature screw, microgear, microshaft, chip leadframe, and IC-socket.
The study assumes constant shear friction to carry out 6-stage the finite element forming simulations, the 5-stage forging forming and 1-stage piercing forming are simulated to obtain the dimensions of dies by Deform 3D FEM analysis software. The effective stress, the effective strain, the velocity field and the forging force in each stage can be obtained. In each stage, the realistic multi-stage forging has been performed to compare the product dimensions with the stimulation results to verify the acceptance of FEM analysis model. The similarity reaches over 95%. With a view to realizing the stress distribution of dies, especially explore the circumferential stress, the radial stress, and the effective stress of inner mold, the outer mold, and the stress ring occurred by single fit interference and the stress ring fit interference. Furthermore, checking whether the effective stress of die occurred exceeds the allowable yield strength of die material to avoid the die failure. The research results proposed have of great important influence to the fastener industries. © 2014, Chinese Mechanical Engineering Society. All right reserved.
A micropress system developed by the National Institute of Advanced Industrial Science and Technology (AIST), which uses microdies and strip materials, can machine submillimeter order profiles at 60 shots per minute using a series of in-line press machines. Although this system is an effective machining device for microfabrication, it is disadvantageous in terms of material consumption. In the strip material feeding system, much of the material becomes scrap, which is eventually thrown away after machining. Transfer press processing, a technique involvingmachining precut material to the product size and transferring it between press machines, is an effective method for reducing material waste. Transfer press machining has already been realized at a large scale. However, there have been few attempts to apply the transfer press to micropress machining. In this study, we developed a new microtransfer hand system for the microtransfer press. The developed transfer system can move the material in reverse or half-rotate it for value-added press machining. A test bench was developed for a transfer experiments to check the microtransfer and reverse settings. In the transfer experiments, this system achievedmicrotransfer with a success rate ofmore than 99%. A time-budget schedule was considered to improve the transfer time rate. The relationship between the grasping force of the transfer fingers and the success rate was examined as the first step in analyzing the stability and rapid transfer of work piece.
A wide range of industrial applications, current and anticipated, drive the process of miniaturization of thermal and chemical devices. In certain cases, metal-based microsystems enjoy advantages of performance, cost, or both, over silicon-based counterparts. The critical bottleneck restricting the use of metal-based microsystems in actual applications has often been the lack of effective and economical manufacturing methods for metal-based microparts. In this paper, our recent efforts in fabrication of metal-based high aspect ratio microscale structures through various replication strategies, such as compression molding and roll molding, are summarized. The need for engineering surfaces of microscale replication tools through conformal coating deposition is illustrated. Two attempts to experimentally measure shear strength of coating/substrate interfaces are described. An estimate of the limiting shear strength of coating/substrate interfaces is achieved through examination of transverse coating cracks induced by substrate tensile loading. Experimental data obtained from two series of TiN/Cr/steel and TiN/Ti/steel specimens are presented. Issues associated with this approach are discussed. Direct failure of coating/substrate interfaces has been induced through compression loading of micro pillars containing inclined coating/substrate interfaces. Preliminary experimental results obtained from TiN/Ti/Si micro pillars are presented.
Many fasteners used in electromechanical systems are micro metal parts which should be manufactured with high accuracy and reliability and in large quantities. Micro forming is promising to fulfill these demands. This research focuses on investigating a gripping unit in a multi stage former, as the positioning unit was discussed earlier. The parameters which play important roles in the gripping unit will be discussed and the precision and reproducibility evaluated to show the performance of the unit. This includes two different tests. The first test will show how accurately the unit can locate the parts and the second one is intended to depict how the unit transfers the parts with different diameters with respect to the front profile of the fingers. The experiments showed that the manipulator can handle the parts with 7 µm accuracy, 2 µm reproducibility and 9µm uncertainty for a 20mm distance between two adjacent stations.
The “micro-world” is a very interesting case of study both for production and research reasons. The use of micro-products and components has had a heavy increase in the last two decades. The manipulation of micro-elements has then become an important need to be satisfied in order to complete production cycles or allow the handling of these components. This paper focuses on a particular case study belonging to the bio-mechanical field. The key point, trigger of the research, has been the need to define a system capable of handling a specific bio-component during a part of its production cycle. In the particular application, the manipulation device has to follow strict requirements of precision, accuracy, and delicacy, because of the dimensions and deformability of the bio-component. The research then has started with an exhaustive analysis of the state of the art, followed by the design and the practical realization of a manipulator matching the specific implementation but whose characteristics could be employed also for other applications. Thanks to the modularity of the design, the device can be easily adapted to any circular micro-element requiring precision and no damaging effects during its manufacturing, motion, or positioning phase.
Multi-step micro bulk forming is characterized by complex processes and high precision requirements. In particular the demands regarding handling accuracy between different forming steps are of the order of a few μm. The paper introduces a methodology for the analysis and characterization of this transfer system on component level and system level. Laser interferometry is used in combination with analytical models to predict the positioning ability of the actuator in a static as well as dynamic mode. In combination with an analysis of the grippers, a full description of the transfer precision inside the forming press is obtained.
Biomedical markets are large and rapidly growing owing to increasing demand for better healthcare services. The development of innovative biomedical systems can produce major breakthroughs in the healthcare industry, and advanced manufacturing technologies can propel such innovations. This paper summarises the field of biomanufacturing: namely, biospecific design constraints, biomechatronics, biofabrication, biodesign, and assembly. This paper presents state-of-the-art research, current problems, and future goals while providing fundamental knowledge required for entry into the biomedical industry. Biomanufacturing provides excellent opportunities for multi-disciplinary collaborations, both in academia and industry, and can lead to further advances in many engineering fields.
Product miniaturization is an emerging trend for facilitating product usage, enabling unique product functions to be implemented in micro-scaled geometries and features, and further reducing product weight and volume. Recently, a demand for microparts increased significantly in many industry clusters. Development of the advanced micromanufacturing technologies for fabrication of such microparts has thus become a critical issue. Microforming, which offers attractive characteristics including high productivity, low cost and good quality of the formed parts, provides a promising approach to fabricating metallic microparts. In the last two decades, a lot of effort has been made to the researches on size effect related deformation behaviors in microforming process and the development of the process. Having a panorama of these researches is necessary to support micropart design and development via microforming, and further advance this micromanufacturing process. In this paper, an intensive review on the latest development of microforming technologies is presented. First of all, the paper is focused on the review of the size effect-affected deformation behaviors and the mechanisms of the changes of flow stress, flow behavior, fracture behavior, elastic recovery, tooling–workpiece interfacial friction and the surface finish of the formed parts. The state-of-the-art microforming processes, including micro deep drawing, microembossing, micropunching, microcoining, microextrusion, microheading, and micro progressive forming are then presented. Finally, some research issues from the implementation of mass production perspective are also discussed.
Machine material handling is complicated in micromanufacturing since standards are not applied and existing handling systems are not flexible. Usually, machine handling systems are highly dependent of microcomponent properties. If the microcomponent is changed, the handling system is also changed. The aim of this paper is to propose a packaging station based on a standard carrier to provide a product-independent inter-machine handling system. Microcomponents are arranged into standard carriers for unifying transport systems. This packaging station was designed to accomplish micro-bulk-forming requirements, but its modular design and its low microcomponent dependencies permit to easily adapt the station to new applications.
In our prior study, a progressive forming system to fabricate meso-scaled bulk cylindrical and flanged parts by using sheet metals has been developed. In this forming system, the cylindrical part is formed via blanking, while the flanged part is formed via the progressive punching, extrusion and blanking. In forming of the flanged part, the preform is attached to the metal strip and positioned based on the geometry of preform. The formed part is finally trimmed out by shearing in the last operation. In such a way, the transporting, positioning and ejecting of preform/part are facilitated. In this paper, the research is aimed at further studying the feasibility of forming microscaled parts by using the previously developed forming system and examining its characteristics based on the material flow behavior, microstructure evolution, the quality and property of the final formed parts. It is revealed that the length of blanked cylinder decreases with the increase of grain size. When the grain size is large compared to the workpiece thickness, an inclined fracture surface is formed on the blanked cylinder and the rollover surface on the flanged part becomes rough. A rough fracture surface with microvoids is formed after shearing operation. The number of microvoids on the fracture surface decreases with the increase of grain size. The developed process is proved to be promising and efficient for mass production of bulk microparts directly using sheet metal.
Titanium is a popular material for medico components, primarily due to its excellent properties as regards strength, resistance
to corrosion and biocompatibility. The disadvantages are mainly the low formability at room temperature and the material cost.
As an alternative to conventional machining, the component can be plastically formed by a number of warm forming operations.
Commercial pure titanium, grade 1, 2 and 4, is tested in 4 dimensions to investigate the size effect as function of temperature
and strain rate. From these tests, a heat treatment procedure is derived and reliable data for a numerical model is acquired.
The concept is validated by forming a dental implant. Due to the high aspect ratio of the tool inserts, a segmented die design
is proposed. A two-step process design with pre-stressed die inserts is realized; following from the high yield strength of
the titanium material that causes internal pressures above 2500MPa under forging. The design phase is supported by numerical
modeling.
Microforming is a well suited technology to manufacture very small metallic parts, in particular for mass production, as they are required in many industrial products resulting from microtechnology. Compared to other manufacturing technologies microforming features specific economical and ecological advantages. Nevertheless, there are only some singular applications known until today. This paper tries to find out the reason why, analyzing systematically the problems emerging in transferring the know-how on forming from the macro- to the microworld. Reviewing the state of the art in basic and applied research reveals that scaling effects do appear not only within the process but must be taken into account in all the other areas of the whole forming system as well, demanding finally new solutions especially for tool manufacturing and machine concepts. Recent progress, innovative ideas and new developments on these sectors represent a promising basis to exploit the inherent potential of microforming in the future.
Manufacturing techniques for production of small precise metallic parts has gained interest during recent years, an interest led by an industrial demand for components for integrated products like mobile phones, personal digital assistants (PDAs), mp3-players and in the future for spare parts for the human body. Micro components have also found several applications within the medical, audiological and dental industry, applications that impose increased demands for biocompatible and corrosion-resistant materials and cleanness. So far these micro components have mainly been manufactured by traditional machining techniques or chemical etching. However, these traditional machining and etching techniques are generally not well suited for mass production of advanced micro components, due to handling problems, waste of expensive material and long machining times. This calls for development of a novel production system that can meet the demands for high productivity, high reliability, low cost, while being environmental acceptable. Bulk metal forming meets these demands to a great extent, but the technology cannot directly be transferred to the micro scale. A flexible machine system for bulk micro forming has been developed and used to form a number of industrial micro parts in aluminium and silver, with ongoing work on forming of titanium. Manufacture of billets by cropping has been examined using a simple test rig and an automatic cropping device has been designed, manufactured and tested.
This paper reviews the new concept "microfactory" and related developments. Machined parts are becoming progressively smaller so production machinery that remains a conventional size is often inappropriate for such products. The term "microfactory" represents an entirely new approach to design and manufacture that minimizes production systems to match the size of the parts they produce. It leads. to conservation of space and energy, and. the reduction of investment and operational costs, as well as the reduction of emissions and the load on operators. Furthermore, it provides a system with dynamic reconfigurability, aiming at a light and agile manufacturing system optimized for current manufacturing needs in a borderless and highly competitive market. In Japan, research institutes, research consortia, and the private sector have carried out targeted research and development aimed at this concept for over a decade. Some systems are past the research stage and in daily use. Outside Japan, the philosophy and advantages of microfactory have reached an appreciative audience in the U.S., Europe, and Asia; Microfactory is at the cutting edge of competitive manufacturing in the 21st century, ushering in a multidimensional paradigm shift. Here we also briefly examine some future tasks.
A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5μm layers with a sponge-like structure. The pores will act as lubricant reservoirs during severe forming processes. The deposited microporous layer is evaluated by friction tests in the form of ring compression tests and double cup extrusion tests. Furthermore the anti-seizure properties are investigated by single cup extrusion at high reduction and excessive stroke comparing with conventionally lubrication using phosphate coating and soap.
In manufacturing of metallic components, the size of the part plays an important role for the process behaviour. This is due to so called size effects, which lead to changes in the process behaviour even if the relationship between the main geometrical features is kept constant. The aim of this paper is to give a systematic review on such effects and their potential use or remedy. First, the typology of size effects will be explained, followed by a description of size effects on strength and tribology. The last three sections describe size effects on formability, forming processes and cutting processes.
Simulated load–stroke curve for the first forming operation with different values of friction factor
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[ ( ) T D $ F I G ] Fig. 8. Simulated load–stroke curve for the first forming operation with different values of friction factor.
Photographs of the formed specimens after the first (left) and second (right) operation. Both specimens are Aluminium EN 6061 material
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- M Arentoft
T D $ F I G ] Fig. 10. Photographs of the formed specimens after the first (left) and second (right) operation. Both specimens are Aluminium EN 6061 material. M. Arentoft et al. / CIRP Annals -Manufacturing Technology 60 (2011) 335–338