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PurposeThe purpose of this paper is to improve the mechanical and thermal properties of photosensitive resin for rapid prototyping (RP) by modifying with nano‐TiO2.Design/methodology/approachThe silane coupling agent was selected to treat the surface of anatase nano‐TiO2 particles. The IR spectrum showed that the hydroxyl (−OH) group on the surface of nano‐TiO2 reacted with the coupling agent effectively. The effects of TiO2 content on the curing depth and viscosity of the photosensitive resin were studied by experiments. The mechanical properties including tensile strength, tensile modulus, flexural strength and hardness were tested according to ASTM standards. The thermal stability of modified photosensitive resin was tested by differential scanning calorimetry.FindingsThe comprehensive performance of the modified photosensitive resin was good when TiO2 content was at 0.25 per cent, the tensile strength was increased by 89 per cent from 25.26 to 47.82 MPa, the tensile modulus increased by 18 per cent from 2,001 to 2,362 MPa, the flexural strength and the hardness increased by 6 and 5 per cent, respectively. In addition, the plasticity and heat stability of modified photosensitive resin were also improved obviously.Originality/valueThe paper provides a low‐cost method to greatly improve the performance of photosensitive resin for RP. The modified photosensitive resin prepared according to the formulas in this paper has been successfully employed in RP equipment of Xi'an Jiaotong University, China.

The traditional slicing method of reverse engineering has been used in product measure from time immemorial. This method however has the disadvantage of low contrast of the cross-sectional pictures of an object. In order to overcome the said shortcoming, a new slicing method of reverse engineering, based on the principle of refraction and reflection of a prism, has been propounded. According to the reflectivity of the object, one of the illuminating methods—straight illuminating or inclined illuminating—is adopted. These methods can enable one to obtain the image of the cross-section of a bright object with a dark background or the opposite. Experiments have proved to show the advantages of this new slicing method for high contrast of the cross-sectional pictures. To eliminate geometrical distortions caused by the refraction and reflection of the prism, a mathematical transformation model can be set up to correct the image by using relevant software. Eventually, a RP model of a temporomandibular joint fabricated according to its slicing pictures is illustrated.

In order to build the complex built-in labyrinth design of an emitter which is a key element in water-saving devices, rapid prototyping and manufacturing (RPM rapid tooling (RT) for the emitter has been fabricated using a metal spraying process to carry out trial-production. Finally, with the fabrication ofa precision mould as the basis, emitter mould design and manufacturing have been completed. As a result, the integration of design/verification/manufacturing of a mould and its products is realised.

The resist filling behavior is crucial to the quality of the final imprinted pattern in micro/nanolithography. To obtain resist flow fields, a three-dimensional (3-D) defocusing digital particle image velocimetry (DDPIV) system was set up to realize the visualization of the resist filling process. Three-dimensional motion trajectories and velocity vectors of tracer particle sets were calculated to characterize this microscale flow phenomena. The results show that the particles’ maximum velocity is located in the region below the mold corner, and the region leans to the mold cavity. Meanwhile, the squeezed resist will first move along the mold moving direction, and then fills the mold cavity in an upward moving tendency when it passes through the mold corner. The feasibility of using the DDPIV system to investigate the resist filling behavior was confirmed. The results will help to understand the resist filling behavior and provide useful instruction for the selection of process parameters and mold structure optimization.

In microimprint lithography, the resist deformation directly influences the quality of the final imprinted patterns. The resist velocity field was investigated through numerical simulations and visualization experiments. A numerical model based on the computational fluid dynamics was built to predict the resist filling behavior. Meanwhile, a 3D defocusing digital particle image velocimetry (DDPIV) system was developed to achieve the microscale velocity field of resist. The spatial coordinates of the fluorescent tracer particles were derived from their defocused images, and then the three-dimensional particle field and velocity field inside the resist were obtained according to the particles' spatial coordinates and time interval recording the particle images. The investigation of the velocity field, including the horizontal and vertical velocity history, was performed to help describe the filling mode and flow behavior of the resist. The experimental results agreed well with the simulation prediction, which justified the use of the micro DDPIV system to investigate the resist filling behavior and verified the numerical model. The combined effect of the mold's local asymmetric geometries and resist's initial thickness on its own deformation was further analyzed by numerical simulation.