The blame contact of coating ply is online measure

2 those who be used at besmearing layer ply is not a contact to measure is compound measure a head to measure primary reason eddy to circulate feeling component and capacitance pass feeling component to comprise compound pass feeling the principle structure that measures a head. Corresponding circuit. When coating of the park that measure a head is expressed and the distance is D2, two sensor measure the space that give to be D2 and D1 respectively, and measures coating thickness is D2-d1 namely. This is ply of pair of the coating on metallic matrix that the article puts forward the fundamental that has is not osculatory metrical. The electric vortex flow of metallic matrix surface flows according to as opposite as electric current of the coil that measure a head way, it passes coil and mutual induction of photograph of annulus of electric vortex flow, make coil impedance produces change. The size of this change depends on the space size between coil and metallic matrix (will be in hind article is expatiatory) , such, the change that adopts impedance of the coil that measure a star can evaluate the size of D1. Use cricoid capacitance sensor to detect normally the clearance of film of qualitative coating of not electric material, because film won't resemble electrode in that way action. Here the circumstance falls, produced two kinds of capacitor between sensor and workpiece: One kind is the cricoid capacitance because of cricoid and electrostatic generation, its size depends on clearance D1; Another kind is the normal capacitor that produces by place of normal and electrostatic location, its size depends on clearance D2 and D1. If shed sensor to detect to D1 by electric eddy, the change that can give these two kinds of capacitance through measuring will obtain D3. The structure that measure a head is complex pass feeling the structure that measures a head. It has a coil to regard cylinder of park of detector of electric vortex flow as the center of the box, additionally two cricoid electrode regard cricoid capacitance as detector, surround coil is coaxial installation. Using cricoid structure is to rise measure sensitivity, because electrode area is increased,overcome those who cause at the same time the defect with the not compact structure that measure a head. Use manganese - zincic core structure is to increase the enlarge multiple of coil sensor (gain) . In addition, core construction can avert the interference of capacitance sensor. Steeliness crust ground connection can reduce exterior noise. The geometrical size that measures a head and electromagnetism parameter see a table 1. Express the 1 geometrical parameter that measures a head and diameter of electromagnetism parameter coil 0.

09(mm) circles the number that make a group (I, j) 8.

13(is encircled) outer lane radius (R1) 4.

215(mm) incentive frequency (multiple of Gc) 100(kHz) enlarge 5.

31 electrode R1, r2, r3, r4 3.

4, 4.

4, 4.

6, 5.

6(mm) ply (TeIe) 18(µm) incentive frequency 1.

5(MHz)3 is compound pass feeling the impedance that measures a head - the electromagnetism action between the coating film that the metallic matrix that eddy of clearance model report circulates the model of feeling component passes feeling component and span two kinds to be D1 and span are D1 concerns. Coil is many only group coil simplify. The impedance of each coil gets the influence of other coil and annular cable vortex flow, but, once coil geometry parameter is given hind, the photograph between coil is decided toward working relationship. Accordingly, electric vortex flow is the only factor that affects impedance change. Closely related it and distance D1. Electric eddy circulates the impedance model of feeling component can press type obtains: 1 Σ of Ze(d1)=Ze0-(j ω · Σ Mi, in type of 1/2 of ω of Eµ σ of √ of Rj)/Te= of × of J-k · Ik)/1NcNe(1)Ne=(5, ze0 is when sensor is far from workpiece initiative slant buy quantity, ω is the frequency of incentive electric current, mi, j-k is K annulus of electric vortex flow and (I, j) pass the coefficient of mutual inductance between feeling coil, lk is in K the electric vortex flow in coil annulus, I is incentive electric current, nc is what to circle coil (the pen number of I × J) , ne is number of annulus of electric vortex flow, te is to guide effectively magnetism deepness. Ik and Mi, j-k is by B Iot-Savart law place is decided, according to type (2) and type (3) pushs: 1 · of Ik={-j ω Mi of I · Σ , 1 · of J-k}/{RK+j ω (in type of Mk-k)}NeNe-1(2)(3) of LK+ Σ , rk and Lk are true resistor is mixed K of eddy current annulus feel oneself coefficient Mk-k is K with K the coefficient of mutual inductance between eddy current annulus, and µ0 is free space guide magnetism is led. Depend on as a result of coefficient of mutual inductance Zi, it and D1 concern into linear, the impedance that sends feeling coil follows distance D1 and change, because this can adopt the change of coil impedance,measure so that be apart from D1. The model that power source infects feeling cell the capacitance size between two electrode gets the influence of coating film and metallic matrix. Should be apart from when D2 is very big, produce cricoid capacitance Cr only, it is described by function of Er of shellfish a place of strategic importance. When D2 decrescent, what arise is normal capacitance, mix in 2 electrode namely the capacitance Cn between coating film, 1 with Cn, 4, and the capacitance Cn between coating film and metallic matrix, 2 with Cn, 3. As a result of normal capacitance Cn, I is series connection, and the brim is messy capacitance is paralell connection, total capacitance Ct can press friend type (4) gets: (In 4) type, ε 0 parting with ε is the interpose report coefficient with free space and coating qualitative material. Ain and Aout are the valid area area of electrode inside and outside respectively, by coulomb law derivation comes out, namely Ain=Ain0Rae, in Aout=Aout0Rea(5) type, ain0 and Aout0 are electrode of inside and outside respectively and indigestion, ri(i=1, 2, 3, 4) is the radius of electrode of inside and outside respectively, y1 and Y2 are the aleatoric dot of every electrode respectively. Finally, the impedance model of capacitance sensor but by type (6) obtains: ZC(d1, in D2)=ZC0+1/j ω 2Ct(6) type, ZC0 is when sensor is far from workpiece initiative slant buy quantity, ω 2 it is incentive voltage frequency. The electromagnetism parameter conductivity that expresses 2 sensor and test specimen (%IACS) guides magnetism is led relatively (coefficient of report of µr) opposite interpose (ε ) metallic matrix is brass 24.

391- aluminous 6061 42.

021- red copper 99.

Polyethylene of 101- coating material- - 3 emulation results are aimed at 3 kinds of base metal (brass, aluminous 6010 with red copper) with material of coating of a kind of polyethylene, come through emulating the bamboo that place of test and verify designs the impedance model that measures a head and actual measurement result closes level. The electromagnetism parameter of these material determines by academy of Korea standard science and affirm (KRISS) , rank expresses 2. Once gave the parameter that measure a head, criterion manganese - zincic magnetism yoke becomes a linear amplifier that sends feeling coil to have the job. Such, magnify diploid Ge can serve as emulated coefficient of proportionality. Gotten impedance state is emulated when different distance D1. Regard blame contact as metrical interval, when D1 increases and the conductivity of base metal is reduced, impedance changes decrescent. This is worn with respect to meaning be ignorant of, when the clearance of eddy current sensor and workpiece exceeds some to be apart from. It will cannot undertake well and truly metrical. This makes clear, to having the metallic matrix test specimen of ply 100µm coating, emulation result and test result are very consistent. Below ply of two kinds of different coating the change is apart from D1 when, the impedance change circumstance of two electrode. Here is put in D1 of an inflection point, namely the span of sensor and metallic matrix is when this bits capacitance impedance is the biggest. Type of no less than (4) place describes, should going up originally under time base of this inflection point is normal capacitance, and cricoid capacitor produced after exceeding this inflection point. The range under inflection point is very narrow, as a result is not a contact to measure coating at be in accurate control comes true hard when film is deep. When coating ply achieves 100µm, the consistency of emulation result and test result got very good test and verify. Accordingly, although clearance must exceed inflection point,measure. From two kinds of afore-mentioned emulation results attainable following conclusion: ① measures range effectively for 0.

5 ～ 0.

8mm; ② is measuring coating before film is deep, the steep inclined part that can use impedance curve will discern metallic matrix. Test facilities of 4 tests result and test specimen survey an experimental plant that surveys coating ply with what we develop. Metallic matrix can move in X axial; Measure a head to also can move in X axis direction, its resolution is 20nm. When blame contact measures morning result to measure, the pace is driven into electric machinery measure a head to move in X axis direction, mobile limits is 0.

5 ～ 1mm. To be in metallic matrix is aluminous the coating of on 3 kinds of 6061 different ply, measurement when the distance is D1 result: , measuring range 0.

5 ～ 0.

When 8mm, measure an error to be less than ± 1 µm; But increase when clearance D1 exceeded 0.

When 8mm, the error greatens; When the distance D1 is 0.

When 5mm, the correspondence measurement at ply of 3 kinds of coating, ply is 100 µm coating measure most the error is the biggest, its reason is to detect the impedance change of the capacitance sensor of thicker coating wants when thinner than detecting coating small. Go up in matrix of 3 kinds of different metals, when coating ply is 80µm, the measurement when distance D1 changes result. When measuring a head to approach sample, what can decide metallic matrix is phyletic. Measure an error because of what metallic matrix differs and cause by again automatic demarcate.

To matrix of 2 kinds of metals, be in when D1 limits 0.

5 ～ 0.

When 8mm less than, measure an error to be less than ± 1µm. Red copper has best conductivity, in bigger measurement inside limits (0.

5 ～ 1mm) , its measure an error far be less than ± 1µm. Test result makes clear: Measure the measurement between head and base metal space is less, measure a result to had been jumped over, be close to copy to expect a result really more. 5 conclusion consider to put forward ply of a kind of coating to be not the new method that the contact measures originally, developed a kind new-style and compound pass feeling measure a head. Advocate main research sums up as follows as a result: As a result of compound pass feeling when measuring a head to build a model, considered two kinds to pass feeling component to be mixed at metallic matrix relatively the electromagnetism of film of not electric coating is characteristic, because this emulates result and actual measurement result,have very good consistency. The emulation result that infects feeling cell to capacitance makes clear, should measure knit clearance to be in 0.

5 ～ 0.

Measure when 8mm less than effective. Use electric eddy to circulate the impedance of feeling component changes, define the sort of metallic matrix likely. Go up in matrix of 3 kinds of metals, when coating ply is 45 µm, 80µm and 100µm respectively, those who use article development is compound measure a head to undertake is not osculatory metrical, should measure range for 0.

5 ～ 0.

When 8mm, measure precision can achieve ± 1µm or smaller. CNC Milling CNC Machining