The Technique And Principle Of Polymer Isothermal Hot Embossing In Solid-like State

Polymer materials were widely used in all industries since they had been invented.They are especially popular in micro deformation because of low cost,ideal property and simple machinability which are favor for manufacturers.The trend has made polymer micro-nano machining most properous in manufacturing industry nowadays.Micro hot embossing is a simple thermal forming method both for technology and device,which has huge development prospect.But it also has some serious defects like long work cycle and low efficiency.In this paper,a new technique named Isothermal Hot Embossing in Solid-like State(IHESS)is proposed for solving the long work cycle problem.The new technique allow polymer to be embossed near the solid state in a low temperature.So the mold can keep isothermal status during the whole cycle because there is no demolding difficulty.Embossing efficiency is promoted tremendously after steps of mold cooling or heating has been removed.In this paper,a confirmation of polymer machinability in solid-like state was built on a mass of researches for polymer constitutive relationship.According to temperature condition of IHESS,behaviors of polymer in molding were listed.The mathematical expressions were derived with corresponding physical models.IHESS and traditional hot embossing could be described by the same constitutive model for a heat-force process.The difference between two methods is only a different proportion of several deformations.Two types of IHESS technique(pre-heating IHESS and no-pre-heating IHESS)and their technological process are studied in this paper.Some laws of technique factors and products quality are acquired by simulated analysis on microstructure forming.According to these laws,some samples of optical microstructures with splendid copy-rate and double-sided LGP with clear profile are produced by experiments.In this papar,the molding influence of microstructure's geometrical characteristics is also discussed via establishment of geometrical models and FEA.The filling features of PMMA in IHESS tech are summarized by researches on the relationships between molding and geometrical characteristics like depth,width-to-thickness ratio,shape and scale.With technique and device,several optimized schemes are proposed for the real operation of IHESS.According to optimized schemes,a new IHE-200A embossing device has been made by lab recently.Most new samples have the better quality in the repeat works of past experiments.