Machining approach of freeform optics via fast tool servo diamond turning

2021 ◽  
Author(s):  
yanjun guo ◽  
xiaojing yang ◽  
tong yao ◽  
guangyuan du ◽  
xueying wang
Keyword(s):  
Diamond Turning ◽  
Fast Tool Servo ◽  
Freeform Optics

Design and Control of a Novel Fast Tool Servo Used in Diamond Turning of Freeform Optics

2016 ◽  
Vol 679 ◽  
pp. 73-78
Author(s):  
Fu Jing Tian ◽  
Zi Qiang Yin ◽  
Sheng Yi Li
Keyword(s):  
Low Cost ◽  
Model Identification ◽  
Voice Coil Motor ◽  
Diamond Turning ◽  
Free Form ◽  
Fast Tool Servo ◽  
Freeform Optics ◽  
Periodic Signals ◽  
And Control ◽  
Free Form Surfaces

Optical free-form surfaces are becoming more and more popular in the industry application, which can be fabricated by diamond turning based on fast tool servo (FTS). It is an efficient, precise and low-cost processing method. In order to use diamond turning to fabricate the freeform optics, this paper develops a novel long range fast tool servo which is actuated by voice coil motor. The total range can reach up to 30 mm. The important parts of the FTS have been simulated and analyzed. The transfer function model identification of the FTS has been accomplished. Since the desired tool trajectories are approximately periodic signals in freeform surfaces turning, and the adaptive feedforward cancellation (AFC) control can achieve perfect tracking and disturbance rejection of periodic signals, the AFC control is designed to be added on the IMC-PID controller.

Tri-axial Fast Tool Servo Using Hybrid Electromagnetic-Piezoelectric Actuation for Diamond Turning

2021 ◽  
pp. 1-1
Author(s):  
Zi-Hui Zhu ◽  
Li Chen ◽  
Yuhan Niu ◽  
Xiaonan Pu ◽  
Peng Huang ◽  
...  
Keyword(s):  
Diamond Turning ◽  
Piezoelectric Actuation ◽  
Fast Tool Servo

scholarly journals Measurement and Compensation of Tool Contour Error Using White Light Interferometry for Ultra-Precision Diamond Turning of Freeform Surfaces

2020 ◽  
Vol 14 (4) ◽  
pp. 654-664 ◽  
Author(s):  
Kodai Nagayama ◽  
◽  
Jiwang Yan
Keyword(s):  
White Light ◽  
High Efficiency ◽  
Diamond Tool ◽  
Microlens Array ◽  
Diamond Turning ◽  
Contour Error ◽  
Form Accuracy ◽  
Freeform Optics ◽  
Ultra Precision ◽  
Quick Measurement

In ultra-precision diamond turning of freeform optics, it is necessary to obtain submicron-level form accuracy with high efficiency. In this study, we proposed a new method for the quick measurement and compensation of tool contour errors to improve the form accuracy of the workpiece. In this method, the nanometer-scale contour error of a diamond tool is quickly and precisely measured using a white light interferometer and then compensated for, before machining. Results showed that the contour of a diamond tool was measured with an error less than 0.05 μm peak-to-valley (P-V) and the feasibility of error compensation was verified through cutting experiments to create a paraboloid mirror and a microlens array. The form error decreased to 0.2 μm P-V regardless of the contour error of the diamond tools when cutting the paraboloid mirror, and that of the microlens array was reduced to 0.15 μm P-V during a single machining step.

Diamond Turning Freeform Optics

2007 ◽  
Vol 364-366 ◽  
pp. 1-6
Author(s):  
W. Jiang ◽  
Bill Tse ◽  
Roy Louie ◽  
Frankie Chan
Keyword(s):  
Diamond Turning ◽  
Freeform Surface ◽  
Work Piece ◽  
Freeform Optics ◽  
Milling Method ◽  
Slow Tool Servo ◽  
Optics Industry ◽  
Optics Fabrication ◽  
Five Axis ◽  
Machining Parameter

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.

scholarly journals Multi-Physical Design and Resonant Controller Based Trajectory Tracking of the Electromagnetically Driven Fast Tool Servo

Actuators ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 28
Author(s):  
Imran Hussain ◽  
Wei Xia ◽  
Dongpo Zhao ◽  
Peng Huang ◽  
Zhiwei Zhu
Keyword(s):  
Natural Frequency ◽  
Trajectory Tracking ◽  
Voice Coil Motor ◽  
Diamond Turning ◽  
Analytical Models ◽  
Physical Parameters ◽  
Fast Tool Servo ◽  
Element Analysis ◽  
Loop Control ◽  
Resonant Controller

In this paper, a voice coil motor (VCM) actuated fast tool servo (FTS) system is developed for diamond turning. To guide motions of the VCM actuator, a crossed double parallelogram flexure mechanism is selected featuring totally symmetric structure with high lateral stiffness. To facilitate the determination of the multi-physical parameters, analytical models of both electromagnetic and mechanical systems are developed. The designed FTS with balanced stroke and natural frequency is then verified through the finite element analysis. Finally, the prototype of the VCM actuated FTS is fabricated and experimentally demonstrated to achieve a stroke of ±59.02 μm and a first natural frequency of 253 Hz. By constructing a closed-loop control using proportional–integral–derivative (PID) controller with the internal-model based resonant controller, the error for tracking a harmonic trajectory with ±10 μm amplitude and 120 Hz frequency is obtained to be ±0.2 μm, demonstrating the capability of the FTS for high accuracy trajectory tracking.

Ductile-Regime Machining for Fast Tool Servo Diamond Turning of Micro-Structured Surfaces on Brittle Materials

2012 ◽  
Vol 500 ◽  
pp. 333-338 ◽  
Author(s):  
De Ping Yu ◽  
Yoke San Wong ◽  
Geok Soon Hong
Keyword(s):  
Experimental Investigation ◽  
Brittle Material ◽  
Brittle Materials ◽  
Diamond Turning ◽  
Fast Tool Servo ◽  
Entire Surface ◽  
Structured Surfaces ◽  
Simulation Based ◽  
Ductile Regime Machining ◽  
Machining Characteristics

Micro-structured surfaces on brittle materials, e.g. ceramic and glass, are gaining increasing application in a range of areas. In this paper, fast tool servo (FTS) diamond turning has been applied to machine micro-structured surfaces on brittle materials and the machined surfaces has been observed to study its machining mechanism. A machining model is presented to enable ductile-regime machining of the brittle material. Based on the model, machining characteristics can be predicted for given cutting conditions. Experimental investigation on machining of a micro-structured surface verified that ductile-regime machining can be ensured on the entire surface through path planning simulation based on the machining model.

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