Abstract
Hot embossing is one of the main processing techniques for polymer microfabrication, which helps the LIGA (UV-LIGA) technology to achieve low cost mass production. When hot embossing of high aspect ratio microstructures, the deformation of microstructures usually occurs due to the demolding forces between the sidewall of mold inserts and the thermoplastic (PMMA). The study of the demolding process plays a key role in commercial manufacturing of polymer replicas. In this paper, the demolding behavior was analyzed by Finite element method using ABAQUS/Standard. Simulation identified the friction force caused by interface adhesion and thermal stress due to shrinkage between the mold and the polymer as the main sources of the demolding forces. Simulation also showed that the friction force made a greater contribution to the deformation than thermal stress, which is explained in the accompanying theoretical analysis. To minimize the friction force the optimized experiment was performed using PTFE (Teflon) as anti-adhesive films and using Ni-PTFE compound material mold inserts. Both lowered the surface adhesion energy and friction coefficient. Typical defects like pull-up and damaged edges can be reduced.
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References
Heckele M, Bacher W, Muller KD (1998) Hot embossing—the molding technique for plastic microstructures. Microsyst Technol 4:122–124
Pollock HM, Maugis D, Barquins M (1978) The force of adhesion between solid surfaces in contact. Appl Phys Lett 33:798
Tian Y, Zhang P, Liu G, Tian X (2005) The lifetime comparison of Ni and Ni-PTFE moulding inserts with high aspect-ratio structure. Microsyst Technol 11(4–5):261–264
Worgull M, Heckele M (2004) New aspects of simulation in hot embossing. Microsyst Technol 10:432–437
Zhang P, Liu G, Tian Y, Tian X (2005) The properties of demoulding of Ni and Ni-PTFE mouding insert. Sens Actuators A118:338–341
Acknowledgment
This work is supported by National Natural Science Foundation of China (No.10375058).
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Guo, Y., Liu, G., Zhu, X. et al. Analysis of the demolding forces during hot embossing. Microsyst Technol 13, 411–415 (2007). https://doi.org/10.1007/s00542-006-0225-9
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DOI: https://doi.org/10.1007/s00542-006-0225-9