Join grating feet and numerical control device (go up)

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One, the connection principle plan that the task introduces numerical control device and grating rule is shown 1 times like the graph, the basis pursues 1 have link, observe the weaveform of grating feet with digital oscillograph. Graph the connection of device of 1 numerical control and grating feet 2, the task is analysed from the graph 1 in the XS32 interface that can see grating feet and numerical control unit is linked together, detected signal feedback gives numerical control the system, the shift to the machine tool (rotational) undertake controlling. What is grating? How does grating work? What position detects device? How to detect the error of the positional measurement unit in numerical control system? We undertake explaining to these problems below. 3, relevant knowledge 1. Grating feet measures systematic grating feet to if the graph is shown 2 times,survey a system, it by illuminant 1, lens 2, rear sight grating 3, demonstrative grating 4, photosensitive component 5 handle circuit composition with signal. Signal handles circuit to have enlarge, plastics and function of Xiang Beipin of ancient bronze mirror again. Normally the circumstance falls, outside following workbench to move together except rear sight grating and workbench outfit, circuit of component of grating of illuminant, lens, directive, photosensitive and signal processing all is installed inside a housing, an alone component secures make it to go up in the machine tool. This component calls grating to read a head, its action is the electric pulse signal that Mo Er the signal of stripe changes into place to need. When moving together along with workbench when rear sight grating, after illuminant passes condenser, form through rear sight grating and demonstrative grating ignore bright ignore dark Mo Er stripe (smooth signal) ; Photosensitive component changes smooth signal into telegraphic date, photograph of the enlarge that handles circuit through signal next, plastics, ancient bronze mirror is outputted after times frequency or show. Change direction to measure, want to place two photosensitive component at least, both apart 1 ／ pitch of 4 Mo Er stripe, move when Mo Er stripe so when, can get two signal phasic differ π ／ the weaveform of 2; output signal sends warning to circuit, can judge mobile direction. Graph 2 grating feet measures one illuminant of systematic L; 2 one lens; Grating of 3 one staff guage; Grating of 4 one directive; Component of 5 one photosensitive the resolution to raise grating, still use the methodological fractionize of 4 times frequency normally. 4 times more alleged frequency fractionize, namely the every pulse signal with Mo Er original stripe, turn into in ／ of O, π 2, ／ of π , 3 π 2 when have pulse output, make precision raised 4 times thereby. If grating bar is apart from 0.

Olmm, criterion workbench every are mobile 0.

0025mm, the system can send a pulse, namely resolution is 0.

0025mm. This shows, the resolution that grating feet surveys a system depends on not only the bar of grating feet is apart from, and depend on photograph of ancient bronze mirror the diploid N of times frequency, namely: Resolution = bar is apart from / N 2. Grating is metric grating is the nice detecting element that is used at numerical control machine tool, it is a kind of uses morer measurement unit in closed circuit system, use as the measurement of displacement or corner, measure precision to be able to amount to a few micron. (The sort of 1) grating and precision are in of glass apparently make transparent as equal as opaque interval strain line, call transmission grating; Total reflection and the strain line with removed and equal diffuse reflection are made on lens face of the metal, call reflex bar, also can have strain line make it the directional grating of certain and diffractive angle. Metric grating cent is long grating (measure linear displacement) He Yuanguang bar (measure angular displacement) , and the different cent that avery kind of pledges according to its utility and material again is a variety of. 1) linear grating (grow grating namely) grating of ① glass transmission. It is the grating strain line that go up in the coating of material of vitreous surface sensitization or makes on metallic plated film, useful also quarter candle, corrode, Tu Hei craft is made. The geometrical dimension of grating basically is mixed according to the length of grating strain line installation circumstance is specific and affirmatory, if pursue,3 are shown. The characteristic of vitreous transmission grating is: Illuminant can be used perpendicular and incident, photoelectricity component can accept smooth signal directly, signal range is accordingly big, reading head structure is simple; The strain line number on every millimeter is much, general and commonly used black and white grating can accomplish every millimeter 100 lines, repass circuit fractionize, can accomplish the resolution of micron class. Graph metal of ② of 3 transmission grating reflexes grating. Be use on steel rule or the lens side that stainless steel takes take a picture to corrode craft to make or use diamond knife stripe of the direct depict grating that make. The characteristic of metallic reflex grating is: Coefficient accomplishs the linear expansion of rear sight grating very easily to agree with machine tool material; Install and adjust of rear sight grating more convenient; Installation area is lesser; Receive the grating of steel belt length that grow or makes whole root easily; Touch not easily broken. At present number of commonly used every millimeter strain line is 4, 10, 25, 40, 50. Round grating of 2) round grating is to be on the outer shroud end panel of vitreous disc, make it is black and white and removed stripe, be in according to diverse use demand circumferential the strain line number that attend is not same also. Round grating has 3 kinds of forms commonly. ① 60 into make, be like 10800, 21600, 32400, 64800 etc; ② is decimal, be like 1000, 2500, 5000 etc; ③ binary system, be like 512, 1024, 2048 etc. The structure of round grating is shown 4 times like the graph. Graph the precision of the precision grating testing system of metric grating of 3) of 4 round grating basically depends on grating feet is noumenal production precision, namely metric grating random the error between 2 o'clock, accumulate an error namely. Because used technology of Mo Er stripe, accordingly, photograph adjacent error is able to amend appropriately, but how old to accumulating an error to not have improvement. As a result of the development of laser technology, grating makes precision can rise, at present grating precision can reach micron level, repass fractionize circuit can be accomplished 0.

1 μ M, higher even resolution. The precision data of a few kinds of commonly used grating sees a table 1. Strain line of length of metric grating grating counts the precision that expresses all sorts of 1 grating 100050/mm7 of grating of reflex of high accuracy of M of μ of bar 122040/mm13 of reflex of metal of M of μ of 50025/mm7 of grating of reflex of metal of straight formula of M of μ of 1000LOO/mmlO of grating of transmission of glass of M of μ of 500100/mm5 of grating of precision glass transmission.

300250/mm1 of grating of diffraction of glass of 5 μ M.

Week of 27010800/ of Φ of round grating of glass of type of circumgyrate of 5 μ M 3 ″ (2) transmission is linear type and graph of grating of type of Mo Er stripe 5 grating position detects device grating position detects device by illuminant, long grating (rear sight grating) , short grating (demonstrative grating) wait for composition with photoelectricity component, if pursue,5 are shown. According to the working principle of grating cent is transmission straight formula and grating of type of Mo Er stripe two kinds. 1) transmission is linear the structure of straight formula grating is like type grating transmission the graph is shown 6 times, the change of change of light and shade that it is the generation when consumed report component moves two grating is the means that electric current changes. Long grating outfit is on component of machine tool shift, call rear sight grating; Short grating outfit secures a component to go up in the machine tool, call demonstrative grating. Rear sight grating and demonstrative grating all by narrow the strain line with opaque rectangle and comprise with the wide transparent interval such as its. When rear sight grating when opposite strain line is perpendicular and mobile, illuminant shoots photoelectricity component by field lens focusing again through rear sight grating and demonstrative grating, if the strain line of demonstrative grating and rear sight grating are transparent removed complete coincide, the luminous flux that photoelectricity component accepts is the smallest. If indicate the strain line of the strain line of grating and rear sight grating complete coincide, the luminous flux that photoelectricity component accepts is the biggest. Accordingly, in process of shift of rear sight grating, the luminous flux that photoelectricity component accepts ignore big ignore small, produced the electricity of approximate sine wave. Change of reoccupy electron circuitry is a number to be measured in order to show displacement. Move to discern direction, the strain line that indicates grating staggers 1/4 bar is apart from, undertake discerning to circuit through ancient bronze mirror. Because this kind of grating can pass through transparent interval only, luminous intensity is so weaker, pulse signal is not strong, often in grating line thicker circumstance is used. Graph 6 transmission are linear graph of type grating principle pursues what grating of type of stripe of Mo Er of type grating 2) uses 7 Mo Er stripe more generally is grating of type of Mo Er stripe, be be apart from bar identical rear sight grating and demonstrative grating to fold the clearance that put and keeps certain parallelly each other (0.

1 ㎜) , had turned demonstrative grating inside oneself plane next a very small angle θ , so the reticle across on two grating feet, below the illuminate of illuminant, black line overlaps inside the zonule near photograph node, transparent area greatens, the area that block light is the smallest, the effect that block light is the weakest, pervious to light accumulation makes this area appears bright belt. Contrary, be apart from photograph node to jump over remote region, the jackknife part of opaque black line jumps over two grating little, the space that black line occupies increases, block smooth area to increase consequently, the effect that block light increases, only less light passes through grating and make this area appears shady area. If the graph is shown 7 times, stripe of alternate with of this light and shade says for Mo Er stripe, its luminous intensity distributings approximate Yu Zhengxian is undee. If will indicate the shift of parallel of direction of length of grating of grating edge staff guage, can see Mo Er stripe also follows shift, but mobile direction and direction of demonstrative grating shift are perpendicular. When the directive grating moves when a reticle, mo Er stripe also as it happens has moved a stripe. 4, the task is carried out 1.

The join of grating feet and numerical control device (1) basis pursues 1 have numerical control system and grating foot link, right now signal of feedback of grating feet position just uses the real position of indication reference axis, did not use the closed-loop control that serves as the position. Microscope wiring, make sure wiring is correct. (2) sets the parameter of communication servo axis of numerical control system. (3) sets the parameter that exchanges servo unit, buy of made working v/arc be on the throne controls means to fall. CNC Milling CNC Machining