Injection Molding And Research On Key Technology Of Microfluidic Chip With Nano- And Micro- Structure

Plastic microfluidic chip is a typical product with nano- and micro- structures. Now, It's used widely in chemical test, biological test, medical test and so on. Plastic microfluidic chip is fabricated by micro injection molding mainly. Not only need to be overcome the macroscopic defects (such as shrinkage depression, warping deformation, burning, weld mark, silver lines and so on), but also the microscopic defects (such as nano- and micro- structure which is not complete copy, structural damage and so on) need to be solved. Therefore, the research on micro injection molding process of microfluidic chip with complex nano- and micro- structure is significant for micro injection molding technology and microfluidic chip technology.The rectangle microfluidic chip with micro pillars array which is used in one-time intelligent diagnosis of myocardial blood and the disc microfluidic chip with nano- and micro- periodic structure which is used in virus diagnosis were researched in this paper. The outer diameter and thickness of the disc microfluidic chip with nano- and micro- periodic structure were 62 mm and 0.6 mm separately. The center hole was constituted by two circles with 15 mm diameter and 3 mm diameter. Many micro grooves distributed on the microfluidic chip. There were nano- Periodic structure distributing on the micro groove with the width of 0.15 mm. The length, width and thickness of rectangle microfluidic chip with micro pillars array were 100 mm,16 mm and 1 mm respectively. There were more than 13000 micro pillars with the diameter of 50?m and height of 40?m and more than 1000 micro pillars with the diameter of 100?m and height of 120?m on the substrate of the rectangle microfluidic chip with micro pillars array. The capillary force which was used to provide power of the rectangle microfluidic chip was formed by the clearance between micro pillars array. The relationship between the injection molding process parameters and the injection molding quality of nano- and micro- structure and the effect of automatic die-cutting gate were explored in the paper.First, according to use machinery design software of Pro/e and AutoCAD, the micro injection mold was designed. The polymer melt fluidity of microfluidic chip was simulation analysis by Moldflow analysis software. And the action of automatic die-cutting gate in mold was simulation analysis by Deform analysis software.Second, for the microfluidic chip with micro pillars array, the relationship between micro injection molding process parameters and micro injection molding quality were researched. The height distribution of micro pillars array along and against flown direction and the micro injection molding quality of micro pillars array were explored, according to change the parameters value of mold temperature and injection speed.Third, for the microfluidic chip with nano- and micro- periodic structure, the relationship between micro injection molding process parameters and micro injection molding quality were researched. The copy quality of nano- periodic structure and the micro injection molding quality of micro channel were explored, according to change the parameters value of mold temperature and injection speed.Finally, Minitab software was used to design L25 orthogonal experiment. In the orthogonal experiment, punching depth and cutting-off degree were set as the target parameters to explore the relationship between different process parameters and the die-cutting effect. And the process parameters which influenced the die-cutting effect mostly were selected. Though the single factor experiment, the relationship between the punching depth and the process parameters which were determined by orthogonal experiment was explored. The quality of die-cutting gate was observed by universal tool-measuring microscope.