Fabrication of 3D submicron to micro textured surfaces using backside patterned texturing (BPT)

- Backside patterned texturing (BPT) is introduced for the fabrication of submicron to micro scale surface features using ultraprecision diamond machining.
- Unlike from conventional methods, BPT produces the controlled surface features without any external gadgets or synchronized tool-spindle motion.
- BPT methodology is presented and various types of freeform surface textures like arrays of bumps with mirror surface quality are formed.
- Surface textures having the height (tb) from hundreds of nanometer to few micrometers are successfully fabricated.
- The texture profile height (tb) is a function of workpiece thickness, machining parameters and backside pre-fabricated pattern.

This work presents a novel fabrication method for submicron to micro size textures on flat surfaces using the backside patterned texturing (BPT). The proposed method utilizes the pre-fabricated macro-features on the backside of work material, and thereafter the front side is face turned with a single point diamond tool to generate textured surfaces. Different from existing texturing methods, BPT produces textured surfaces from submicron to micro scale without any external gadgets such as vibration assisted machining or synchronized tool-spindle motion. The miniature feature arises on the diamond turned surface due to the induced residual stresses when the specimen is unleashed from the machine. To demonstrate the efficacy of the method, a series of machining experiments were conducted to fabricate various types of freeform surface textures like water-drop freeform, cylindrical freeform surfaces, etc. The fabrication methodology of different sizes of bumps with precisely controlled surface quality is illustrated. The texture profiles comprising the deformation height from hundreds of nanometer to few micrometers with mirror surface quality were successfully fabricated on the diamond machined surface. The experimental results suggest that the pre-fabricated pattern, workpiece thickness and machining condition play a critical role to determine the final shape and geometry of generated textures.