Papers by Keyword: Slow Tool Servo

Abstract: Embossing by patterned rollers is one of the most efficient machining approaches for manufacturing plastic films with patterned microstructures, and the precision roller with patterned microstructures is the key tooling component in the roll-to-roll process. Single-point diamond turning with a slow or fast tool servo is an enabling and efficient ultra-precision machining process to fabricate microstructures through a simple process to achieve optical surface finish directly. Most of the current studies on slow or fast tool servo machining processes either focus on face machining of patterned microstructures, or on tool servo machining of microstructures in the radial direction of precision rollers. Relatively little research work is found in relation to machining patterned microstructures on a precision roller by using the tool servo in the axial direction. This paper presents a pilot study on the development of a tool path generator for machining precision rollers with wavy patterned microstructures by using slow tool servo machining in the axial direction on a precision roller. The machining mechanism is firstly explained, based on which the tool path generator is developed for machining wavy patterned microstructures on a precision roller surface. Preliminary experimental work was conducted to study the generation of wavy patterned microstructures on a precision roller using a four-axis ultra-precision machine. The machined wavy microstructures on the roller surface are measured and analyzed to successfully validate the performance of the proposed tool path generator.

Abstract: This study describes the non-rotationally symmetric diamond turning (XZC turning) for producing large-size precision freeform mirror. This is a high speed machining method as compared with the traditional XYZ diamond milling or fly-cutting. Moreover, the application of this method is a key factor in the development of the ultra-precision light-weight freeform mirror for outer space use. This report introduces these cutting-edge approaches.

Abstract: In this paper, a five-axis ultra precision machine tool for fabrication of microstructured surfaces is presented. This machine consists of two rotary axes (C&B) and three linear axes (X&Y&Z). High precision aerostatic bearing and torque motor are adopted in C axis (main spindle) and B axis. X axis and Z axis use the hydrostatic guideway and are driven by linear motors. Y axis is driven by torque motor and precision ball screw. This machine is able to realize multiple processing methods, including ultra precision diamond turning, ultra precision milling, fly-cutting, fast tool servo and slow tool servo diamond turning.Furthermore, a large number of experiment researches are carried out. Some typical microstructure surfaces are manufactured, for sinusoidal grid surface, the surface roughness Ra is 11.9nm, which is machined by slow tool servo diamond turning. Micro pyramid array surface is fabricated by using fly-cutting, which performs well both in the profile accuracy and the repeatability. These experiment researches prove that this ultra precision machine is superior in accuracy and system reliability.

Abstract: To solve the difficulties in machining toric spectacle lens, the turning method with slow tool servo was discussed. First, the experimental setup was developed, which have X-axis, Z-axis and C-axis, and the movement of the three axes can be simultaneously controlled by numerical control system. Then, the mathematical model of toric was established, and its machining model was analyzed and simulated. Finally, the machining experiments were carried in the experimental setup. The experiments showed that the turning method based on slow tool servo can meet the requirements for machining the toric spectacle lens.

Abstract: Owing to the fast development in photonic, telecommunication, and opto-electronic industries, the demand for various micro-lens arrays is rapidly growing. The slow tool servo technique was applied on an ultra-precision diamond turning machine in the present research in conjunction with the tool path generating algorithm for aspheric micro-lens array fabrication. An aspheric lens array of 100% filling factor was successfully produced and the form accuracy and surface roughness were better than 0.15μm and 3nm for all the obtained lenses.

Abstract: Freeform optics fabrication has become one of the hottest topics in optics industry in recent years. Although it still remains a challenge, many have tried different ways of manufacturing it. Some have achieved degrees of success. By means of a Nanotech 350-FG five axis diamond turning machine, we too have successfully produced some prototype freeform optics and lens arrays with Slow Tool Servo and Milling method. The produced freeform optics are mainly for automobile LED headlamps and the lens arrays are for LED illumination. In order to produce the freeform optics, we developed our own DT Slow Tool Servo program which is capable of generating a DT program for diamond turning a universal/general 3D freeform surface. Slow Tool Servo technique and Diamond Milling technique were mainly employed to produce these freeform surfaces. The manufacturing process and machining parameter details will be given in the paper. The two main methods we used will be compared and discussed as well. In measuring the freeform surface, a 3D white light interferometer was used to scan and obtain the surface coordinates. The software made by ourselves enabled us to compare the measure results of the work piece with that of the design drawings. The deviation of our finished forms is within 5 um from that of the nominal. The surface quality Rq is about 10 nm. Measuring equipment and methodology will also be discussed in the paper.