Integral leaf dish blade face CMM measures method program technology

Integral leaf dish be blade and hub make it a whole, have weight light, hold in esteem compares amount of big, spare parts to wait for a series of advantages less, the application in advanced aviation engine is accordingly wider and wider. Integral Xie Panfen is type and shut type two kinds, if pursue 1 with the graph 2 are shown. As a result of whole Xie Panjie form is complex, blade face is complex and free curved surface, twist is spent big, treatment precision demand is high, the passageway between photograph adjacent lamina is deep and narrow, sex opening open is poor, because this creates integral part of a historical period dish it is difficult to make relatively odd blade, also measure for its accordingly increased difficulty. Use 3 coordinate to measure machine (Coordinate Measuring Machine, CMM) is measured is to measure integral leaf at present dish the most effective method. Use measure machine to Xie Panxing the face undertakes metrical, want to undertake method plans above all, the stand or fall that method plans decides the efficiency that CMM measures and effectiveness. Document [1-12] measures method to planned to undertake study to CMM of free curved surface respectively. Although Xie Panxing face belongs to free curved surface, but the limitation as a result of the structure, its measure method to plan to have the characteristic of its oneself, the article to whole Xie Panxing face measured the relevant and crucial technology in method program to undertake study. Integral Xie Pance measures method to plan to be in integral leaf dish in measuring, to measuring blade those who measure sectional number and measurement point number is affirmatory and number, special important. Measure number to be able to increase too much detect cost, reduce measure efficiency; Measure number to be able to be reduced too less again right overall representative, increase measure an error. The 1 affirmatory whole leaf that measures blade number dish blade distributings by Zhou Xiangjun divide evenly, in machining a process, all lamina are through rotating by same treatment technology, same machine program workpiece coordinate fastens treatment to finish, blade has certain consistency, so integral leaf dish blade can adopt sampling means to detect. Because of integral leaf dish computation of size of the sample when blade samples randomly attributes proportion model do not repeat sample randomly, so the turned example into the capacity certainly affirmatory issue that blade counts. The affirmatory process that blade figures is the balance process of charge and precision substantially. The requirement of the end that should consider to detect already, detected property and precision, want to consider the maneuverability that operates actually again, the control that is not error of sampling. After having integrated balance, obtain a best sample size option. On the other hand, specific project, charge formed the general budget of the project to detect again blade number has an upper limit. Measure number to be able to break through budgetary tie greatly too, bring about overspend. Set funds amount to be C, charge function can express to be: C=C0+nC1, (1) among them, c0 is fixed charge, have nothing to do with sample size; C1 is average the measurement that each lamina unit needs charge, solve the measurement that go out from this blade counts N, can regard funds as a postulate of the tie. (1) fundamental. To estimation scale variable, decide sample size formula is: · of N1=Z2 · P (1P)/e2, (2) among them, n1 represents sample size; Z states the statistic below believe level is measured; The proportion that P represents the objective is overall expects to be worth; E expresses believe interval half wide, investigate an error namely. Undertake correction greatly to sample size according to sample gross: N2=n1.

(N/N+n1) , (3) among them, n is blade gross. Sampling because of example is not to use simple sample randomly, can use sampling design effect to undertake correction to sample size so: N=B · N2, (4) among them, b is parameter of design effect scale; N is counted to measure blade. Formulary (2) , (3) , (4) parameter takes a value to be able to consult watch 1. Nextpage (2) example application. Some model Xie Panxie of one class whole piece a total 48, because do not have concerned Yu Zhen beforehand solid scale P is available information, accordingly, assume variance takes the biggest case, assume namely P=0.

5; The actual condition according to sampling observation lamina is desirable E=0.

2; It is in believe level 90% , b is taken 0.

Below the circumstance of 65, the basis is formulary (2) , (3) , (4) the lamina that computation gets needing to measure counts N=8.

09 ≈ 8, the blade number that needs to measure namely is 8. 2 lamina measure the dependability that measures of sectional number to assure certainly, blade measures sectional number M to should not be less than 3. (1) according to be being detected the length of blade detects certainly sectional number. Can use formula of the following experience: M=c · L, (5) among them, m measures sectional number to answer; L is blade length; C is coefficient of proportionality (it is 1/10~1/20 commonly) . (2) according to blade theory sectional line number detects certainly sectional number. Take M1/5 of ≥ of M1/3 ≥ M commonly according to experience. Among them, m1 is number of academic and sectional line; M measures sectional number to answer. What measurement point of 3 sectional lines counts is affirmatory when undertaking metrical to free curved surface, use waiting for span to measure is the measurement technique that goes easily the simpliest, but measure span to make sure accuracy must narrow, this makes measure efficiency to be reduced significantly, increased the difficulty of the job such as follow-up error assess. Document [the computation that 13-14] gave out to measure check the number according to machining the craft ability of equipment is formulary, did not concern with the appearance of the spare parts that be measured. A kind of good method makes measure bit of density that distributing to change along with curved surface curvature namely, curvature is bigger, measure a place closer; Jump over conversely scanty, thereby better land report awaits the geometrical appearance news that measures curved surface. The characteristic according to blade face and the requirement that measure bit of distributinging density to change along with curved surface curvature, union measures a situation actually, sectional line measurement point counts the lamina of summary computational formula is as follows: D/3 of · of L of N=L/A+ ρ · , (6) in type, l is measure method length, the photograph adjacent that A leaves a hope for small curvature circumstance measures bit of interval, ρ is circular arc curvature, d issues the measurement point on the semicircle circular arc of the hope to count for big curvature circumstance. The extraction with D is worth A to have a consideration from respect of economy and equipment technology ability, take A=5~15mm commonly, d=5~15. Graph 3 it is a basis formulary (6) the amount of measurement point of circular arc of the semicircle below case of rate of calculative yeast for making hard liquor, take A=10mm, d=10, circular arc radius from R=0.

2mm arrives R=3.

5mm. Can see, r=3mm is the following, measurement point of semicircle circular arc is counted is 10, curvature is smaller, measurement point is more concentrated, measuring bit of several main factors is the curvature of circular arc; R=3mm above, because measure the addition of method length, measurement point number increases, the main influencing factor that measures check the number is to measure length. The position that 4 method plan to measure method to plan to define measurement point namely and measure order. Measure machine basis measurement point coordinate and touch measure direction to undertake metrical [15] . As a result of general measurement machine software system has function of revolving stage scanning, so Xie Pance measures the method with method the most commonly used program is to wait for radius method to plan. Wait for radius law, namely every sectional measurement on blade counts foothold to be in around the leaf dish on the circumgyrate cylinder face of axes line. Nextpage uses this method to be able to cause what cause because of the difference of length of blade leading edge and tailing edge length to measure method line to rupture, if pursue,4 are shown. The article puts forward flow path line to measure way, the air current when flow path line shows blade works sheds the similar line of classics lamina face, the biggest characteristic of its distinction and sectional line is the curve closes. (1) blade face measures method program principle. · measures method line to present even state and cover whole lamina range as far as possible. · measures method line to go up in, the distance between measurement point is decided by curvilinear curvature, in the leaf back face, leaf is basin shaped on the face, the amount photograph of measurement point wants than blade leading edge and tailing edge few and far between. (2) law of flow path line measures method program measure. · basis blade theory is sectional data undertakes to blade face parameter turns model; Edge of the lamina after · changes parameter face its law to slant outwards buy gives equidistant blade face slants buy side, the distance between equidistant face is the radius that measure a head; Curved surface of the hub inside · general slants outwards to direction along its law buy gives equidistant inside hub curved surface slants buy side, the distance between equidistant face is inside radius blend adds hub curved surface and lamina area the radius that measure a head; To closing type whole page dish, what still ask the hub outside taking is inward is equidistant slant buy side, between equidistant face be apart from curved surface of the hub outside be and lamina face radius blend adds the radius that measure a head; Curved surface of hub of · less than slants buy faces blade face to slant buy side undertakes cutting out; To shutting type Xie Panhai wants beyond hub slants buy faces blade face to undertake cutting out; The lamina that · crosses to cutting out face slants buy side undertakes parameter turns model afresh; The lamina that · new parameter changes face slants buy side expresses to be S0, edge lamina face slants the definition of sectional line direction of buy side is U parameter direction, edge lamina face slants the radial direction definition of buy side is V parameter direction, parameter U, V is worth limits standardization to be in the extraction inside S0 [0, 1] ; T1 of ｛ of parameter group Ti= waits in what edge V direction constructs on S0, t2, ... , tn ｝ ; · general Ti of each parameter line, respectively disperse is 4 curves: Line of line of line of foliaceous back flow path, foliaceous basin flow path, leading edge flow path and line of tailing edge flow path; · basis is formulary (6) become curvilinear disperse measurement point, beg the coordinate that takes measurement point and law arrow. (3) example. Graph 5 it is a basis (2) program method begs extraction Xie Pance opening type to measure way, graph 6 it is the Xie Pance that shut type measures way. The number of lamina of the sampling observation in integral Xie Pance putting forward to measure in last word article, affirmatory method that measures sectional number, measurement point number and flow path line measure method method. What narrated a method to rise to measure efficiency, assured to gauge effectiveness, for integral leaf dish on machine measure had done preparative work. CNC Milling