The Laboratory of MicroNano Manufacturing Technology (MNMT) of Tianjin University
The Laboratory of MicroNano Manufacturing Technology (MNMT) of Tianjin University was founded in 2005. It has been mainly engaged in fundamental research and application development of ultra-precision machining and metrology, optical freeform design and manufacturing, bio-medical implants design and manufacturing, focused ion beam fabrication, hard brittle materials machining, micro injection molding and glass molding. MNMT is recognized as one of the leading research organizations in micro/nano manufacturing worldwide.
MNMT focuses on research and development of the following areas in manufacturing:
Ultra-precision Machining Technology
MNMT has the capability to manufacture complex highly precise 3D surfaces with the most advanced ultra-precision CNC machine tools and natural single crystal diamond tools. The advantages of ultra-precision machining include superior accuracy and stability. Surfaces of 1nm in roughness are attainable. A wide range of materials can be ultra-precision machined, such as aluminum, copper, nickel, gold, germanium, ZnSe, ZnS, and PMMA. The extent of ultra-precision manufacturing includes all kinds of plane mirrors, spherical mirrors, concave/convex aspheric mirrors, off-axis aspheric mirrors, aspheric array of mirrors, Fresnel mirrors, micro-groove arrays, multi-faceted prisms, optical molds, and other key components of ultra-precision devices.
Optical Freeform Machining
Ultra-precision machining of freeform surfaces has become the key technology for developing the modern optical, biomedical, communications, and microelectronics fields. As constantly satisfying the surface roughness and dimensional accuracy of the micro-core critical parts, higher requirements for the complexity of surface morphology is also being put forward. MNMT has not only been able to realize mutual transformation of model space and machining space by establishing complex freeform surface model, but also realize the ultra-precision machining of free-form surface via cylindrical coordinate processing technology. MNMT successfully developed a wide range of typical optical surfaces, such as compound eyes, spiral mirrors, aspheric lens arrays, sinusoidal surfaces, and three-mirror freeform optical system.
Brittle Materials Machining
Applications of brittle materials cover a wide range of industries, such as optical, medical, semiconductor, mold manufacturing, etc. However, because of its high hardness and brittleness nature, the critical issue associated with machining brittle materials is a difficulty in achieving precision surfaces with complex shapes. Thus far, MNMT has successfully developed a series of molding methods to improve the capability of precisely machining brittle materials such as cemented carbides, glasses, ceramics, corundum, silicon/germanium with complex 3D profiles. The roughness of the machined surface can reach 0.2μm.
Micro/Nano Fabrication by Focused Ion Beam
Focused Ion Beam (FIB) is a new technique for nano-fabrication and analysis. It is capable of morphology observation, positioning, sample preparation, composition analysis, thin film deposition and etching. MNMT is engaged in developing FIB technology to achieve focused ion beam etching machining combined with on-line high-resolution scanning electron microscope (SEM) detection. Through the gas injection system for platinum deposition combined with micro-operation devices, preparation and structure optimization of micro/nano structures and devices can be realized. Our main research interests include high precision and complex micro/nano structures and devices, micro-cutting tools, carbon nano-tubes, and TEM sample preparation. Currently, MNMT has developed the process to fabricate the Siemens Star, nano-mask with less than a 100nm line width, bio-optical chips, and micro/nano diffractive optical elements.
Precision Micro-injection Molding
Along with the rapid development of optical, bio-medical and communication micro-devices as well as household products, there is a greater need for reliable mass manufacturing of precision components. Precision micro-injection molding provides a new kind of manufacturing method to fabricate micron scale components on the order of milligrams in scale. Apart from simplifying the forming process, precision micro-injection molding also improves the quality of the components, shortens the production cycle, and ultimately lowers cost. MNMT has been able to use a self-developed micro-mold to conduct micro-injection molding process research on high-precision and complex-shaped components of various polymer materials. The automatic adjustment of pressure waveform and metering time, the automatic detection of finished product as well as the protection of the mold can be carried out during the processing to ensure the stable molding quality of product in different processing environments.