Progressive microforming process: towards the mass production of micro-parts using sheet metal

Ghassemali, Ehsan; Tan, Ming Jen; Jarfors, Anders E. W.; Lim, Samuel Chao Voon

doi:10.1007/s00170-012-4352-4

Cited by 61 publications

(40 citation statements)

References 20 publications

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“…A similar galling effect was observed by Ghasemali et al [71] during extrusion of copper micro-pins. Hu et al [72] studied the wear behavior in micro deep drawing tools.…”

Section: Critical Issues Particular To Microformingsupporting

confidence: 84%

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

et al. 2016

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Abstract:The current paper aims to review tooling life span, failure modes and models in cold microforming processes. As there is nearly no information available on tool-life for microforming the starting point was conventional cold forming. In cold forming common failures are (1) over stressing of the tool; (2) abrasive wear; (3) galling or adhesive wear, and (4) fatigue failure. The large variation in tool life observed in production and how to predict this was reviewed as this is important to the viability of microforming based on that the tooling cost takes a higher portion of the part cost. Anisotropic properties of the tool materials affect tool life span and depend on both the as-received and in-service conditions. It was concluded that preconditioning of the tool surface, and coating are important to control wear and fatigue. Properly managed, the detrimental effects from surface particles can be reduced. Under high stress low-cycle fatigue conditions, fatigue failure form internal microstructures and inclusions are common. To improve abrasive wear resistance larger carbides are commonly the solution which will have a negative impact on tooling life as these tend to be the root cause of fatigue failures. This has significant impact on cold microforming.

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“…A similar galling effect was observed by Ghasemali et al [71] during extrusion of copper micro-pins. Hu et al [72] studied the wear behavior in micro deep drawing tools.…”

Section: Critical Issues Particular To Microformingsupporting

confidence: 84%

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

et al. 2016

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“…It can be seen that the characteristic of micro-shearing process customized for progressive microforming is to produce micro-scaled holes by using the sheet metals with different thicknesses. Figure 2 schematically illustrates the characteristics of the progressive microforming process developed by Ghassemali et al [6][7][8][9] for the fabrication of a solid micro-part with a pin at its center. From the figure, it can be seen that the process set-up consists of two stages including pin forming by forward extrusion and blanking.…”

Section: Characteristic Of Progressive Microformingmentioning

confidence: 99%

“…Then the sheet metal with the attached extruded pin is ejected by springs and can be transformed to the next stage [7]. Figure 3 shows the progressive microforming system developed by the authors' group to fabricate multi-step flanged parts.…”

Section: Characteristic Of Progressive Microformingmentioning

confidence: 99%

“…Fu and Chan [4,5] further examined the feasibility of this process to fabricate the meso-and micro-scaled parts by directly using sheet metal, and identified its characteristics via scaling down the part size and using the materials with different grain sizes. Ghassemali et al [6][7][8][9] further developed this process to manufacture the micro-pins by directly using copper strip, which consists of two simple steps, including extrusion and blanking. To ensure the precise positioning, the guide holes are performed on the edge of sheet metal, and the guide pins are utilized throughout the subsequent forming stages.…”

Section: Introductionmentioning

confidence: 99%

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Review on progressive microforming of bulk metal parts directly using sheet metals (Keynote Paper)

Meng

2015

MATEC Web of Conferences

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Abstract. Due to the ubiquitous trend of product miniaturization, energy saving and weight reduction, micro/meso-scale parts have been widely used in many industrial clusters. Micromanufacturing processes for production of such micro/meso-scale parts are thus critically needed. Microforming, as one of these micro manufacturing processes, is a promising process and thus got many explorations and researches. Compared with the research on size effect affected deformation behaviours, less attention has been paid to the process development for mass production of micro-parts. The product quality and fabrication productivity of micro-parts depend on the involved process chain. To address the difficulty in handling and transporting of the micro-sized workpiece, development of a progressive microforming process for directly fabricating bulk micro-parts using sheet metals seems quite promising as it avoids or facilitates billet handling, transportation, positioning, and ejection in the process chain. In this paper, an intensive review on the latest development of progressive microforming technologies is presented. First of all, the paper summarizes the characteristic of progressive microforming directly using sheet metal. The size effect-affected deformation behaviour and the dimensional accuracy, deformation load, ductile fracture, and the surface finish of the microformed parts by progressive microforming using sheet metals are then presented. Finally, some research issues from the implementation of mass production perspective are also discussed.

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“…Yi et al [3] used the micro-punching technology to punch a 15 µm micro-hole on the brass foils with a two-way image acquisition system and punching tools were fabricated by micro electrical discharge machining (micro-EDM). Ghassemali et al [4] researched the feasibility of producing micro-pins with diameters of 0.3 mm, 0.5 mm and 0.8 mm successfully and effects of punch/pin diameter ratio on the pin aspect ratio using a progressive forming set-up. The maximum forming loads were also investigated.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation Research on Micro-Gears Fabrication by Laser Shock Punching Process

Liu

Shen

et al. 2015

Micromachines

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Abstract:The aim of this paper is to fabricate micro-gears via laser shock punching with Spitlight 2000 Nd-YAG Laser, and to discuss effects of process parameters namely laser energy, soft punch properties and blank-holder on the quality of micro-gears deeply. Results show that dimensional accuracy is the best shocked at 1690 mJ. Tensile fracture instead of shear fracture is the main fracture mode under low laser energy. The soft punch might cause damage to punching quality when too high energy is employed. Appropriate thickness and hardness of soft punch is necessary. Silica gel with 200 µm in thickness is beneficial to not only homogenize energy but also propagate the shock wave. Polyurethane films need more energy than silica gel with the same thickness. In addition, blank-holders with different weight levels are used. A heavier blank-holder is more beneficial to improve the cutting quality. Furthermore, the simulation is conducted to reveal typical stages and the different deformation behavior under high and low pulse energy. The simulation results show that the fracture mode changes under lower energy.

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Progressive microforming process: towards the mass production of micro-parts using sheet metal

Cited by 61 publications

References 20 publications

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

Tool Wear and Life Span Variations in Cold Forming Operations and Their Implications in Microforming

Review on progressive microforming of bulk metal parts directly using sheet metals (Keynote Paper)

Experimental and Numerical Simulation Research on Micro-Gears Fabrication by Laser Shock Punching Process

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