Modeling of large area hot embossing

Worgull, Matthias; Kabanemi, Kalonji K.; Marcotte, Jean-Philippe; Hétu, J.‐F.; Heckele, M.

doi:10.1007/s00542-007-0493-z

Cited by 23 publications

(23 citation statements)

References 12 publications

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“…Due to the large embossing area, the parts were replicated with forces of up to 800 kN to minimize shrinkage and guarantee the filling of all cavities (Worgull et al 2008).…”

Section: Interstage Mold Inserts Replicated In Technical Thermoplasticsmentioning

confidence: 99%

Hot embossing of micro and sub-micro structured inserts for polymer replication

et al. 2010

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Today replication of microstructured parts is state of the art in laboratory and commercial use. Beside the process of injection molding hot embossing enables the accurate replication of polymer structures in a broad variety of thermoplastic polymers even in the nanometer range. Characteristic for the most replication processes dealing with thermoplastic polymers is the use of microstructured mold inserts based on metals. In this paper we describe an alternative to the established mold inserts--the use of so called interstage mold inserts. These interstage mold inserts are replicated in high performance polymers and technical thermoplastics and can be fabricated many times by a previous replication step from a master even in the submicro range. Aspects like suitable material combinations, demolding behaviour, long time stability, production rate, and the quality of structures will be discussed. Because of the high flexibility the process of hot embossing is used for the fabrication of the microstructured interstage mold inserts and their replications.

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“…Due to the large embossing area, the parts were replicated with forces of up to 800 kN to minimize shrinkage and guarantee the filling of all cavities (Worgull et al 2008).…”

Section: Interstage Mold Inserts Replicated In Technical Thermoplasticsmentioning

confidence: 99%

Hot embossing of micro and sub-micro structured inserts for polymer replication

et al. 2010

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“…Sacrificial features outside the functional area were proposed to protect the remaining features. Worgull et al [21] presented a contact and friction model to simulate friction during the demoulding phase. The existence of a static friction coefficient is assumed.…”

Section: Embossingmentioning

confidence: 99%

“…The existence of a static friction coefficient is assumed. Worgull et al [22] presented results regarding the modelling and simulation of large area replication based on an eight inch microstructured mould.…”

Section: Embossingmentioning

confidence: 99%

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Delaney¹,

Bissacco²,

Kennedy³

2010

Proceedings of the 7th International Conference on Multi-Material Micro Manufacture

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Demoulding components without damage to either the components or tool is critical to successful replication processes. During tooling development designers strive to optimize replication tools to minimize demoulding force and resultant stress on replicated parts. A critical element of this process is an accurate demoulding force prediction model. Various models have been proposed to predict demoulding forces, each showing limitations in its applicability. This paper reviews existing demoulding force models and parameters affecting demoulding force for micro polymer replication.

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“…A simulation model for de-embossing has been created using non-linear transient thermo-viscoelasticity equations. However, due to its complexity it needs finite element methods [9]. To advance the development of nanopatterning techniques, specifically NIL, a largely analytical model would help by allowing trends to be identified and the relative magnitude of the dependencies and effects of different variables to be assessed.…”

Section: Introductionmentioning

confidence: 99%

Optimization of micro and nanoimprint de-embossing by elastic fracture modelling

Balla

Spearing

2013

Microelectronic Engineering

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A semi-analytical model is presented for the de-embossing phase of the nanoimprint patterning process. The model is based on established principles of elastic fracture mechanics as developed for fibre-bridged cracking in composites. De-embossing is idealised as a steady-state fracture process, which enables the energy change to be considered by reference to a unit cell of a cylindrical polymer post, de-embossing from an axisymmetric stamp. The model provides predictions of the achievable limits for de-embossing as a function of key geometrical variables such as feature size, area ratio and aspect ratio and material properties such as interfacial adhesion, shear strength, polymer yield strength and the ratio of the elastic moduli of the polymer and the stamp. Process 'maps' have been created showing de-embossing limits. A strong dependence of the achievable aspect ratio on the pattern area ratio and the interfacial shear stress is seen. For polymer yield stresses similar to that of PMMA, the critical interfacial strain energy release rate has little effect on de-embossing. Large area and aspect ratios are predicted to be achievable by keeping the ratio of polymer and stamp Young's moduli between 0.015 and 2.5. The model provides key insights into the physical origins of previously observed limits on the achievable aspect ratios and area ratios achieved by imprint patterning. Keywords NIL, nanoimprint, de-embossing, analytical, modelling, process maps Notation R = unit cell radius, δ = displacement, z = distance, z = slip length, τ = shear stress, σ = applied stress, r = radius, f = area fraction, G iC = critical interfacial strain energy release rate, U = strain energy, A = area, E = Young's modulus, V sl = sliding frictional energy, AR = aspect ratio, R E = Young's moduli ratio. Subscripts 0-3 = longitudinal regions of the stamp model, a-c = model state, T = total, p = polymer, c = composite of stamp and polymer, s = stamp yp = polymer yield stress, ys = stamp yield stress, r = radial direction, z = longitudinal direction, rl = residual layer, st = stamp top.

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Modeling of large area hot embossing

Cited by 23 publications

References 12 publications

Hot embossing of micro and sub-micro structured inserts for polymer replication

Hot embossing of micro and sub-micro structured inserts for polymer replication

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Optimization of micro and nanoimprint de-embossing by elastic fracture modelling

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