With nuclear power microscope scanning measures radius of point of diamond cutting tool

The Measuring Images And The Analyzing Results Of Measuring Errors Are Given. The Method Also Has A Directive Significance To The Analysis Of The Influence Of Cutting Edge Radius On Surface Quality. Keywords: Diamond Tool Measurement Of Cutting Edge Radius Atomic Force Microscope (AFM) 　 applies natural diamond cutting tool to undertake to be not metal of iron a group of things with common features and metalloid material cutting is machined exceeding nicety is a kind of important superprecision method. Accordingly, control the geometrical appearance of diamond cutting tool, especially parameter of radius of cutting tool point appears to the influence of superfinishing surface quality particularly important. Measure on international at present inferior the current method of radius of micron class point is scanning electron microscope (SEM) measure law 〔 1 〕 . In recent years, rise ceaselessly as what machine precision, the radius of cutting tool point that machines place of surface exceeding essence of life to use often is less than 0. 1 μ M, it is rice of a few accept about commonly. When the point radius that uses 100nm of ＜ of SEM observation ρ , because resolution is insufficient, image brim is more ambiguous, come true hard accurate measure; And as a result of point surface plating the electric metal film that inaccuracy of a ply decides, make observation result is put in bigger error; In addition, SEM law does not apply to real time to measure. For accurate the point radius that measures accept rice level, 80 time evening, small to exceeding point measures foreign scholar the technology had a large number of research, offerred a few new measurement technique early or late, if imprint membrane method [2] , the law that cut bits [3] , improvement SEM standard [4] wait. But these methods all are indirect measurement, measure precision class of rice of very inaccessible accept. As nuclear power microscope (AFM) the applied escalate in industrial domain, 90 time, a few scholars put forward to use nuclear power microscopical the method that the principle measures radius of point of diamond cutting tool [5, 6] , measurement technique is diamond cutting tool perpendicular put the 2 dimension workbench below AFM bougie to go up, make edge is located in bougie lower part, bougie is perpendicular undertake scanning at point, the AFM that can gain point sweeps draw image. But document [5] , [6] in all did not give out the exact measured value of point radius, also did not undertake an analysis to measuring an error. For this, we use the experiment research that homebred AFM had this is measured, got sectional coordinate is worth point scanning image and a group of point. One, measure principle 　 1. AFM of 　 of AFM job principle uses an one aspect of the matter to secure, another end detects of the stretch small cantilever of bougie sample surface property and feature [7] . Should undertake scanning when very acerb bougie and distance of surface of the sample that be measured are very adjacent, right now, what concern with mutual distance is pinpoint will make with the interaction force between sample surface small cantilever generation bends be out of shape, stimulate illumination to shoot small cantilever the reverse side with a bundle (like the graph 1 is shown) , detect through positional detector the change that stimulates reflection to choose the place, the feature that can get bougie scanning fashion tastes the surface changes. Scanning mode has 3 kinds commonly, namely contact, blame contact and clap type, the AFM job that we use falls in osculatory mode, namely pinpoint contact scanning with sample, both atomic electron cloud overlaps and arise 10 - 8 ～ 10 - the coulomb repulsion force of 11N. Graph 　 of diagram of principle of job of 1 　 AFM 2. Measure main body of measurement unit of cutting tool point to be CSPM with AFM - 930 model nuclear power microscope, refer to a graph 2. Grain of head of knife of diamond cutting tool 5 stickup v/arc be on the throne at scanning earthenware pipe the sample stage of 3 upper part 4 go up, cutting tool is cleaned with alcohol beforehand and blow with clean air dry, edge of the cutting tool that be measured is perpendicular be opposite up bougie 6. Before measuring, control system does part of vertical step pitch for 0. The accurate electric machinery of 3 ° realizes the small feed of bougie, when bougie approachs the cutting tool that be measured, focusing on small cantilever stimulate beam of light to reflex smooth position detector 10 on, small cantilever deflection will by detector the intensity difference in 4 quadrant is worth, when intensity differs value happening to change, the specification already completed probe approach, the pace stops automatically into electric machinery. Of the alignment of cutting tool edge and bougie approach all can pass microscopical photograph like the system 11 observe on monitor. 1. Base 2. Small feed device 3. Scanning earthenware pipe 4. Sample stage 5. The cutting tool that be measured 6. Bougie and small cantilever 7. Laser 8. Before illuminator 9. Hind illuminator 10. Positional detector 11. Microscopical photograph like the system 12. Control a system 13. Advocate accuse the computer to pursue when 2 　 AFM measures fundamental of point of diamond cutting tool, scanning earthenware pipe 3 use sample scanning means to undertake scanning, the feedback system change according to detector voltage, pass to scanning earthenware pipe the 3 Z that add Z direction voltage to adjust the cutting tool that be measured ceaselessly to the position, in order to keep pinpoint the active force with cutting tool is constant, the Z below the record totes earthenware pipe to voltage and correspondence the X of 3 to reach Y to voltage (reflect X respectively to with Y to scanning position) the processing that handles an order through image, can get the sample that be measured -- the space of cutting tool point is three-dimensional form appearance. 2, measure data and analytic 　 1. Measure data to choose instrument parameter: ScanGain ＝ 30, VGain ＝ 1, IGain ＝ 5. The image classics data that scanning gets is changed, turn into the BMP graph file below WINDOWS, if pursue,3 are shown. Graph program of processing of graph of classics of this scanning image processes image of 3 point scanning, get following graphical parameter: Zmin ＝ - 810, zmax ＝ 919, times ＝ 13. 00. Some is sectional if the histogram that after the Z value that nods each handles a program via the graph, gets pursues 4 are shown. Graph sectional point measures 4 some image histogram 　 2. Measure data analysis to choose point radius ρ to regard assess as point sharp spent parameter. According to angle of geometry of cutting tool point (before horn 0 ° , hind horn 7 ° ) , XZ rectangular coordinates department is built on histogram foundation. Point is sectional appearance is be joined by curvilinear circular arc and two straight line segment and become, to circular arc paragraph measure data to undertake least square is handled, coordinate of attainable the centre of a circle and radius R are worth. The method that uses changeover of will round equation to be binary and linear equation (namely the curve changes straightforward way) [8] , get ρ ＝ 120nm via computation, 11nm of ＝ of E of its computation error. 3. The error analyses 　 (1) the image error that causes because of error of detector of position of smooth road sum of errors is very small, it is 1nm about commonly; (2) XOZ plane and Y to not verticality error most greatly 5nm; (3) computational error is 12nm; (4) the image distortion error that bougie radius causes is 2nm about; Measure total error to be above the root of sum of squares of 4 errors, it is 13nm about. 3, conclusion and traditional SEM measure law photograph to compare, AFM measures a way the operation is handy, data is reliable, can realize real time to measure, be a kind idealer outline of acute of point sharp edge measures a way. This method still needs to do following improvement: (1) as a result of point alignment compares difficulty, the enlarge system that needs to increase a long object distance comes those who realize bougie to aim at; (2) it is sample scanning means as a result of instrument itself demarcate, still cannot realize the measurement of large size sample, if change one's costume or dress the instrument,be bougie scanning means, the large size sample that can realize other type cutting tool scans; (3) point assess theory still needs to be perfected further. CNC Milling CNC Machining