| 1. |
- Buckholtz, Ben, et al.
(författare)
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Cloud Manufacturing : Current Trends and Future Implementations
- 2015
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Ingår i: Journal of manufacturing science and engineering. - : ASME International. - 1087-1357 .- 1528-8935. ; 137:4
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Tidskriftsartikel (refereegranskat)abstract
- Manufacturing technology changes with the needs of consumers. The globalization of the world economy has helped to create the concept of cloud manufacturing (CM). The purpose of this paper is to provide both an overview and an update on the status of CM and define the key technologies that are being developed to make CM a dependable configuration in today's manufacturing industry. Topics covered include: cloud computing (CC), the role of small and medium enterprises (SMEs), pay-as-you-go, resource virtualization, interoperability, security, equipment control, and the future outlook of the development of CM.
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| 2. |
- Camuz, Soner, 1988, et al.
(författare)
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Reliability based design optimization of surface-to-surface contact for cutting tool interface designs
- 2019
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Ingår i: Journal of manufacturing science and engineering. - ASME : ASME International. - 1087-1357 .- 1528-8935.
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Tidskriftsartikel (refereegranskat)abstract
- In recent year, cutting tool manufacturers are moving towards improving the robustness of the positioning of an insert in the tool body interface. Increasing the robustness of the interface involves designs with both chamfered and serrated surfaces. These designs have a tendency to over-determine the positioning and cause instabilities in the interface. Cutting forces generated from the machining process will also plastically deform the interface, consequently, altering the positioning of the insert. Current methodologies within positioning and variation simulation use point-based contacts and assume linear material behaviour. In this article, a first order reliability-based design optimization framework that allows robust positioning of surface-to-surface-based contacts is presented. Results show that the contact variation over the interface can be limited to pre-defined contact zones, consequently allowing successful positioning of inserts in early design phases of cutting tool designs.
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| 3. |
- Dahlström, Stefan, 1972, et al.
(författare)
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Variation simulation of sheet metal assemblies using the method of influence coefficients with contact modeling
- 2007
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Ingår i: Journal of Manufacturing Science and Engineering, Transactions of the ASME. - : ASME International. - 1087-1357 .- 1528-8935. ; 129:3, s. 615-622
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Tidskriftsartikel (refereegranskat)abstract
- Sheet metal assembly is a common assembly process for several products such as automobiles and airplanes. Since all manufacturing processes are affected by variation, and products need to have a high geometric quality, geometry-related production problems must be analyzed during early design phases. This paper discusses two methods of performing this analysis. One way of performing the simulations relatively fast is to establish linear relationships between part deviation and assembly springback deviation by using the method of influence coefficient (MIC). However, this method does not consider contact between the parts. This means that the parts are allowed to penetrate each other which can affect the accuracy of the simulation result. This paper presents a simple contact modeling technique that can be implemented in to MIC to avoid penetrations. The contact modeling consists of a contact detection and a contact equilibrium search algorithm. When implemented, MIC still only requires two finite element analysis (FEA) calculations. This paper describes the steps in the contact algorithm and how it can be used in MIC and finally the proposed contact modeling is verified by comparing the simulation result with commercial FEA software ABAQUS contact algorithm.
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| 4. |
- Eggertsen, Per-Anders, 1981, et al.
(författare)
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A Phenomenological Model for the Hysteresis Behavior of Metal Sheets Subjected to Unloading/Reloading Cycles
- 2011
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Ingår i: Journal of Manufacturing Science and Engineering, Transactions of the ASME. - : ASME International. - 1087-1357 .- 1528-8935. ; 133:6
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Tidskriftsartikel (refereegranskat)abstract
- The springback phenomenon is defined as elastic recovery of the stresses produced during the forming of a material. An accurate prediction of the springback puts high demands on the material modeling during the forming simulation, as well as during the unloading simulation. In classic plasticity theory, the unloading of a material after plastic deformation is assumed to be linearly elastic with the stiffness equal to Young's modulus. However, several experimental investigations have revealed that this is an incorrect assumption. The unloading and reloading stress-strain curves are in fact not even linear, but slightly curved, and the secant modulus of this nonlinear curve deviates from the initial Young's modulus. More precisely, the secant modulus is degraded with increased plastic straining of the material. The main purpose of the present work has been to formulate a constitutive model that can accurately predict the unloading of a material. The new model is based on the classic elastic-plastic framework, and works together with any yield criterion and hardening evolution law. To determine the parameters of the new model, two different tests have been performed: unloading/reloading tests of uniaxially stretched specimens, and vibrometric tests of prestrained sheet strips. The performance of the model has been evaluated in simulations of the springback of simple U-bends and a drawbead example. Four different steel grades have been studied in the present investigation.
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| 5. |
- Eynian, Mahdi, 1980-, et al.
(författare)
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Analytical Chatter Stability of Milling With Rotating Cutter Dynamics at Process Damping Speeds
- 2010
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Ingår i: Journal of manufacturing science and engineering. - USA : ASME. - 1087-1357 .- 1528-8935. ; 132:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a chatter stability prediction method for milling flexible workpiece with end mills having asymmetric structural dynamics. The dynamic chip thickness regenerated by the vibrations of the rotating cutter and the fixed workpiece is transformed into the principle modal directions of the rotating tool. The process damping is modeled as a linear function of vibration velocity. The dynamics of the milling system is modeled by a time delay matrix differential equation with time varying directional factors and speed dependent elements. The periodic directional factors are averaged over a spindle period, and the stability of the resulting time invariant but speed dependent characteristic equation of the system is investigated using the Nyquist stability criterion. The stability model is verified with time domain numerical simulations and milling experiments.
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| 6. |
- Eynian, Mahdi, 1980-, et al.
(författare)
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Chatter Stability of General Turning Operations With Process Damping
- 2009
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Ingår i: Journal of manufacturing science and engineering. - : The American Society of Mechanical Engineers. - 1087-1357 .- 1528-8935. ; 131:4
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Tidskriftsartikel (refereegranskat)abstract
- The accurate prediction of chatter stability in general turning operations requires the inclusion of tool geometry and cutting conditions. This paper presents regenerative chip and regenerative chip area/cutting edge contact length based dynamic cutting force models, which consider cutting conditions and turning tool geometry. The cutting process is modeled as it takes place along the equivalent chord length between the two end points of the cutting edge. The regenerative chip model is simple, and the stability can be solved directly. However, the three-dimensional model considers the effect of tool vibrations at the present and previous spindle revolutions on the chip area, chord length, and force directions and is solved using Nyquist stability criterion. The penetration of worn tool flank into the finish surface is considered as a source of process damping. The effects of the nose radius, approach angle of the tool, and feedrate are investigated. The proposed stability model is compared favorably against the experimental results.
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| 7. |
- Fan, Wei, et al.
(författare)
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A Data-Driven Machining Error Analysis Method for Finish Machining of Assembly Interfaces of Large-Scale Components
- 2021
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Ingår i: Journal of manufacturing science and engineering. - : ASME International. - 1087-1357 .- 1528-8935. ; 143:4
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Tidskriftsartikel (refereegranskat)abstract
- To guarantee the final assembly quality of the large-scale components, the assembly interfaces of large components need to be finish-machined on site. Such assembly interfaces are often in low-stiffness structure and made of difficult-to-cut materials, which makes it hard to fulfill machining tolerance. To solve this issue, a data-driven adaptive machining error analysis and compensation method is proposed based on on-machine measurement. Within this context, an initial definite plane is fitted via an improved robust iterating least-squares plane-fitting method based on the spatial statistical analysis result of machining errors of the key measurement points. Then, the parameters of the definite plane are solved by a simulated annealing-particle swarm optimization (SA-PSO) algorithm to determine the optimal definite plane; it effectively decomposes the machining error into systematic error and process error. To reduce these errors, compensation methods, tool-path adjustment method, and an optimized group of cutting parameters are proposed. The proposed method is validated by a set of cutting tests of an assembly interface of a large-scale aircraft vertical tail. The results indicate that the machining errors are successfully separated, and each type of error has been reduced by the proposed method. A 0.017 mm machining accuracy of the wall-thickness of the assembly interface has been achieved, well fulfilling the requirement of 0.05 mm tolerance.
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| 8. |
- Fan, Wei, et al.
(författare)
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Eddy Current-Based Vibration Suppression for Finish Machining of Assembly Interfaces of Large Aircraft Vertical Tail
- 2019
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Ingår i: Journal of manufacturing science and engineering. - : ASME. - 1087-1357 .- 1528-8935. ; 141:7
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Tidskriftsartikel (refereegranskat)abstract
- Assembly interface of aircraft vertical tail is a large thin-wall structure and made from titanium alloys, which causes easily machining vibration, deformation and undercutting in finish machining due to its low stiffness, low thermal conductivity, and high chemical activity. To address these problems, a novel eddy current damper for assembly interfaces machining (ECD-AIM) is proposed to suppress multimodal vibration in the machining of the assembly interfaces. Within the context, the mathematical model of damping performance of the damper is established based on the principle of electromagnetic induction, based on which a novel design of the damper is proposed, and optimized by considering the relationship between damping performance and the key components of the damper. Then, the dynamics model of the suppression system of the assembly interface machining is established, where the relationship between vibration velocity and damping performance of the damper is obtained by using numerical analysis and finite element simulation. Finally, the damping performance of the damper is validated in terms of the three configurations (no applied ECD-AIM, a single ECD-AIM, and dual ECD-AIMs) via a set of dynamic tests (impact tests and harmonic tests) and cutting tests. The test results demonstrate that the configuration of dual ECD-AIMs can guarantee stability and reliability of assembly interface machining. The proposed damper can provide a feasible solution for vibration suppression in a limited workspace.
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| 9. |
- Hu, Cheng, et al.
(författare)
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On the steady-state workpiece flow mechanism and force prediction considering piled-up effect and dead metal zone formation
- 2021
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Ingår i: Journal of Manufacturing Science and Engineering. - : ASME International. - 1087-1357 .- 1528-8935. ; 143:4
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Tidskriftsartikel (refereegranskat)abstract
- The manufacturing of miniaturized components is indispensable in modern industries, where the uncut chip thickness (UCT) inevitably falls into a comparable magnitude with the tool edge radius. Under such circumstances, the ploughing phenomenon between workpiece and tool becomes predominant, followed by the notable formation of dead metal zone (DMZ) and piled-up chip. Although extensive models have been developed, the critical material flow status in such microscale is still confusing and controversial. In this study, a novel material separation model is proposed for the demonstration of workpiece flow mechanism around the tool edge radius. First, four critical positions of workpiece material separation are determined, including three points characterizing the DMZ pattern and one inside considered as stagnation point. The normal and shear stresses as well as friction factors along the entire contact region are clarified based on slip-line theory. It is found that the friction coefficient varies symmetrically about the stagnation point inside DMZ and remains constant for the rest. Then, an analytical force prediction model is developed with Johnson-Cook constitutive model, involving calibrated functions of chip-tool contact length and cutting temperature. The assumed tribology condition and morphologies of material separation including DMZ are clearly observed and verified through various finite element (FE) simulations. Finally, comparisons of cutting forces from cutting experiments and predicted results are adopted for the validation of the predictive model.
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| 10. |
- Jensen, MR, et al.
(författare)
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Aspects of Finite Element simulation of axi-symmetric hydromechanical deep drawing
- 2001
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Ingår i: Journal of manufacturing science and engineering. - 1087-1357 .- 1528-8935. ; 123:3, s. 411-415
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Tidskriftsartikel (refereegranskat)abstract
- A new approach for the Finite Element modelling of the hydromechanical deep drawing process is evaluated. In the model a Finite Difference approximation of Reynold's equation is solved for the fluid flow between the blank and the draw die in the flange region. The approach is implemented as a contact algorithm in an explicit Finite Element code, Exhale2D. The developed model is verified against experiments and good agreement is obtained. It is concluded that the developed model is a promising approach for simulating the hydromechanical deep drawing process using the Finite Element Method.
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