Along with modern science and technology development, Optical precise instrument, especially in space applied optical
precise instrument, all set the very high request in the surface quality and the processing precision aspect, and have
already achieved a nanometer precision to the surface roughness Ra request. Therefore this paper puts forward to use
self-reacting machining method, process for floating polish, as well as measure and analyze the shape, appearance,
roughness of work-piece surface. Through comparing proof with the work-piece surface condition that the grinding
processing method of tradition gets: in from meet processing condition take off , the plasticity region processing that can
be stabilized and realize brittleness optical material gets very good processing surface quality. Under the experiment
condition of this paper, can get Ra 2-3nm processes mirror surface in shorter time.
The dynamic interferometry is used to overcome the problem of the vibration and the air turbulence present in the testing
process of concave aspherical mirror, whose aperture is extra large, and optical path is extra long. Aiming to 4.5m
aperture concave mirror, two schemes have been designed: offner refractive and reflective compensators. The analytical
model of the theoretical error analysis under the dynamic interferometry condition has been built. According to the result
we can come to a conclusion that using the method of dynamic interferometry, the accuracy of measuring can be reached
within λ/80. The optical testing path of mirror with multiple segments has been designed in the end. Results of this paper
could provide references for the design, processing, assembling and testing technologies of large or extra large optical
system.
Due to the high precision and good surface quality that it can give, Electrical Discharge Machining (EDM) is potentially an important process for the fabrication of micro-tools and micro-components. However, a number of issues remain unsolved before micro-EDM becomes a reliable process with repeatable results. To deal with the difficulties in micro electrodes on-line fabrication and tool wear compensation, a micro-EDM machine vision system is developed with a Charge Coupled Device (CCD) camera, with an optical resolution of 1.61μm and an overall magnification of 113~729. Based on the Linux operating system, an image capturing program is developed with the V4L2 API, and an image processing program is exploited by using OpenCV. The contour of micro electrodes can be extracted by means of the Canny edge detector. Through the system calibration, the micro electrodes diameter can be measured on-line. Experiments have been carried out to prove its performance, and the reasons of measurement error are also analyzed.
In order to machine inclined micro-holes and operate in narrow space, a novel miniaturized EDM (Electro Discharge Machining) mechanism has been developed. Because of its merit of compact size (70×40×50mm), the mechanism can be fixed on robot. The prototype of miniaturized EDM system consists of electrode direct drive unit, EDM electrical parameters and servo controller, ultrasonic EDM generator, manual robot, in addition to miniaturized EDM mechanism. Differential Reciprocating Driving Method (DRDM) is presented, and the coaxial forced vibration of electrode can be achieved. Coaxial vibration is applied to promote the evacuation of debris, and it helps to achieve stable and efficient machining. The optimal design of ultrasonic motor has been implemented using Finite Element Method (FEM), and the reasonable structure has been achieved. Feeding resolution of electrode can reach 40nm in differential reciprocating style. The holes with figures of Φ85μm circle, Φ90μm inclined circle, Y and inclined Y have been machined.
This paper presents a new kind of electro-discharge machining (EDM) software computer numerical control (SoftCNC) system which is based on RTLinux platform and Finite State Machine (FSM) method. An EDM SoftCNC function model is given and the structure of SoftCNC based on the function model is proposed. The Binary FSM (Motion FSM and control FSM) model of the whole system is also proposed. To simplify complexities, the system FSM is decomposed to a set of FSMs. The motion decision-making FSM which is the dispatcher of motion tasks is designed. The auto task FSM and interpolate algorithm FSM are proposed. In control FSM, the control signal generator-decoder model is proposed, as well as the auto decision FSM is fabricated. Three abstract layers: function abstract layer, communication abstract layer and hardware abstract layer are designed to enhance enclosure and porting of SoftCNC. Run on MD21 machine, the performance implies that the system is stable, reliable and with low-latency.
Laser forming of sheet is a forming technology of sheet without a die that the sheet is deformed by internal thermal stress induced by partially irradiation of a laser beam. In this paper, the bending behavior of common stainless steel 1Cr18Ni9Ti sheet is studied after being irradiated by straight line with a Nd:YAG pulse laser beam. The aim of the investigation is to find out the relationship of the bending angles with the pulse parameters of the laser. The experimental results show that higher width of pulse is advantageous to increase the bending angles if the total outer power and the rate of the pulse are constant. The bending angle increases as the rate of the pulse increase and begins to decrease at a certain processing parameters. And the bending angle firstly increases with the pulse energy increasing and begins to decrease at a certain processing parameters, as there is a certain pulse energy parameter resulting in a maximum bending angle for a certain material and processing parameters. The pulse energy is the most important factor influences the bending angles of pulse laser forming in the pulse parameters. By qualitative analysis of experimental result, the conclusion obtained may provide basis for theoretical investigation and possible industrial application of laser bending process in the future.
KEYWORDS: Pulsed laser operation, Laser processing, Control systems, Process control, Metals, Quality systems, Head, Laser applications, Electronics, Control systems design
The needs to quantity and quality of cold-rolled steel sheets demanded its fine surface quality. Some efficient methods of surface measurement are introduced to construct a surface quality controlling system. Through theoretical analysis and large amount of experiments, the basic relationship between surface topography and process parameters can be established and the optimal parameters can be got to instruct to obtain more ideal surface of roller and steel sheet.
In order to adapt to the trend of surface quality assessment, the 3D topography measurement becomes more and more important. In metallurgy industry, the topography of roller affects that of cold-rolled steel sheet mainly, which makes it necessary to measure the topography of roller. On the base of traditional light section method and light scanning technique, the triangular light beam scanning method is designed and adopts linear structured light to scanning test surface and acquire height data through demodulating the surface 3D information carried from observation field. Applied with the TLBS surface topography measuring system, some 3D topography examples are given to verify the correctness and feasibility of it.
This paper presents a system to measure three-dimensional profile of a surface, based on the principle of scanning white light interferometry. It adopts a basic structure of Michelson interferometer and semiautomatic fast focus-adjusting mechanism. Through increasing the sampling frequency and applying the feature extracting algorithm, the precision and efficiency of measurement can be increased together.
This paper presents a system for three-dimensional topography measurement, of both smooth and rough surface, based on triangular beam scanning technique. This system utilizes a simple but efficient principle based on the general principle of light-section method and the idea of light scanning technique to acquire topography. Its ability of anti- interference is powerful and it can be used at locale of manufacturing.
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