The AR of signal of vibration of the electrode in process of aluminium alloy spot welding builds model and research

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Summary: The feature of electrode vibration signal that the article studied process of resistor spot welding is medium, built the oscillatory equation of the electrode acceleration signal in spot welding process, the method that uses time domain analysis is vibratory to its can undertake study, from regression through what build AR(n) model calculated: The horny frequency of damp comparing, oscillatory mode and return to power chart function oneself, in addition computational result and actual frit nucleus quality inspection result undertakes contrasting analytic, get following verdict: The horny frequency of damp comparing, oscillatory mode and return to power chart function and frit karyoplasm quantity to have stronger dependency oneself, the feature that can regard quality of aluminium alloy spot welding as differentiate is measured and the different welder of divisional spot welding besides, the frit nucleus quality that considers to be spot welding of aluminium alloy resistor originally detects provide a kind of new measure. Keyword: Aluminium alloy spot welding; Electrode displacement; AR model; Spot welding of resistor of time alignment preface is plank connective important method, be applied in auto industry and aerospace industry widely. In process of resistor spot welding, voltaic classics electrode has shed frit nucleus division, make metallic heat expands, fuse and form frit nucleus, fused quantity of the metal (namely frit nucleus size) , corresponding concern is shown inside certain limits with electrode displacement, because this is OK,through detecting electrode position change comes those who mirror frit nucleus to fashion a process, heat expands electrode displacement law is solder quality of the nucleus that light fuse examines in real time relatively direct with effective method. Come for years, people has soldered to differring stuff of the metal below the standard if the displacement change rule of the material such as armor plate of carbolic steel, excel in steel, galvanization undertook study, also be worn away by pollution, electrode to plank surface at the same time and the contact is undesirable between weldment the electrode displacement that waits for a circumstance to fall undertook study [1, 2] , development gives a few control systems that regard monitoring as parameter with electrode displacement [3, 4] . These research basically are with electrode displacement, electrode speed serves as check to measure, decide one allows wave motion will make sure solder nods frit nucleus quality inside interval. As the car light the application that quantifies material, aluminium alloy is made be used in great quantities to replace data basically, but a few characteristic as a result of aluminium alloy are qualitative, if heat conduction, conductivity is good,be out of shape with easy hot bate, heat wait for a characteristic greatly, have with afore-mentioned material very big different, because this needs pair of existing heat,expand electrode displacement method undertakes data varies study to suit deep. The article had analysis and research to parameter of vibration of electrode of aluminium alloy spot welding, used time series model to collect a few new useful information, will announce with this the metabolic rule of frit nucleus. Specific means is the change and causes vibration that regards the acceleration signal of electrode as You Rong nucleus, answer angle to undertake study to its from oscillatory system, use time domain to analyse a law to build AR(n) to return to a model oneself, beg the mode parameter that sees oscillatory system, the dynamic character that analyses a system from whole by mode parameter again and mode parameter and frit karyoplasm measure the impact between, this research is quality of nucleus of frit of aluminium alloy spot welding to detect provide a kind of new measure. The time domain analysis of 1 oscillatory model and research [5, signal of vibration of 6] electrode displacement is according to proper time early or late order collects, existing between them inevitable causal, and order cannot be adjusted, the analytic method that can use time series will handle. In the analytic method of time alignment, AR(n) has derivation from model of recursive time series time of simple, operation is short wait for a characteristic, it is the model of a total maximum, of the input that output of its T hour is T hour and the output in the past add authority and, AR (N) disperse is from recursive system model: (1) the Xt in type is answered for the system of T hour, at is the incomplete difference of T hour, e (At) be equal to 0, Φ J is from population, semester of E amount to looks at a symbol. Type (2) diagnostic equation is: (2) type (3) it is equation of N second linear, mutual N. N there is solid root to also have compound radical in the root, an oscillatory mode in process of nucleus of frit of trends of every root correspondence. As corresponding as solid root oscillatory mode crosses damp, the oscillatory mode of compound radical correspondence owes damp, it can cause oscillatory system to break firm and change condition, because this article considers the case of compound radical only. By type (1) , (2) λ of attainable feature root, basis (3) , (4) ω of frequency of horn of type plan cipher out and damp compare ζ : (3) the λ in type, λ * is conjugate feature root, Δ is sampling interval (it is Δ ≤ 0.

5f, ) of F sampling frequency. (4) to AR (N) of systematic model return to function of power spectral density oneself, but by formula (5) get: (5) the rank number N of AR(n) model does not know commonly beforehand, need beforehand make choice of a greater value, in the basis in recurrence process final error criterion or judgement of information theory criterion is affirmatory. Check of signal of displacement of electrode of 2 aluminium alloy checks check 2.

Aluminium alloy of 1 test data board use 5052, its ply is 0.

8mm, its clipping becomes rectangle of 5mm × 3mm, the regulation of basis GBJ236 is right aluminium alloy board undertake solder pre-treatment. 2.

2 tests equipment: The experiment uses Panasonic YR-700CM2HGE of machine of communication spot welding, through adjusting voltaic value change solders craft parameter. 2.

4369 sensor of acceleration of testing system of signal of 3 electrode displacement is B&K company, 2635 what charge amplifier is B&K company; Data collects a part to be undertaken by oscillograph of Agilent 54622A memory A/D is changed counting occupying collection mixing, send the computer analytic processing displacement signal by communication interface. 3 AR(n) model is built, in the manufacturing practice of mode parameter computation and result analysis in spot welding, diameter of nucleus of commonly used frit or area regard the evaluation of quality as the standard, namely it is better that frit nucleus diameter or area jump over great quality. But the frit nucleus appearance of aluminium alloy spot welding often is irregular, with the diameter that measures solder place measurement technique will produce bigger error, use in this research so measure tear the method of examining frit nucleus area will reduce an error. The author chose from inside the displacement signal that collects: Area of nucleus of incomplete fusion, frit (be worth for fiducial normalization with primitive electrode end panel) have 5 groups of 36 ％ , 70 ％ , 92 ％ and overheat representative, reflective frit nucleus grows the data example of different situation, build AR(n) to return to systematic model oneself, computation I(i=1 of Φ of each model population, 2, Λ , n) , take the place of type (2) , beg λ of I of solution feature root, by type (3) , (4) beg an as corresponding as each feature root oscillatory mode parameter (oscillatory frequency ω and damp compare ζ ) , its see next tables as a result. Will enter type from population generation (5) , of computational AR(n) model return to function of power spectral density oneself) (ω S, paint corresponding chart picture, see a picture (B) , (D) , (F) , (H) and (J) place is shown, and graph (A) , 2(c) , 2(e) , 2(g) , 2(i) is curve of vibration of the electrode in spot welding process. Express oscillatory mode parameter to be able to see from the watch: Not area of form nucleus, frit nucleus is 36 ％ , 70 ％ , 92 ％ and overheat 5 kinds of circumstances, not form nucleus and overheat its the percentage that energy of the first the highest peak in a mountain range holds whole energy is lesser, all be 8.

48 ％ ; And the situation of form nucleus is different, the proportion that holds is larger, it is respectively: 12.

3 ％ , 19.

75 ％ , 31.

04 ％ , the energy when this specification forms frit nucleus relatively concentration, and progressively growth; Not 2 kinds of circumstances issue form nucleus and overheat, energy is relatively dispersive; Still can see from data, as the accretion of frit nucleus area, its energy of the first the highest peak in a mountain range is in increase by degrees stage by stage. Chart of AR(n) of signal of displacement of graph electrode vibration pursues (curve of A) incomplete fusion (curve of chart of B) incomplete fusion table (area of nucleus of C) frit 36 ％ curve (area of D) frit nucleus curve of chart of 36 ％ table (area of nucleus of E) frit 72 ％ curve (area of F) frit nucleus chart of 72 ％ table, not the damp that 2 kinds of circumstances issue form nucleus and overheat is bigger than numerical value, maximum is respectively 0.

4958, 0.

4502, and 3 kinds of circumstances that nucleus having frit forms, maximum is respectively: 0.

1394, 0.

1381, 0.

259, there is apparent difference between two groups of data. The boundless key link that damp comparing is degree of reflective vibration attenuation coefficient, what damp compares is different concern with electrode displacement and its motion speed, in the graph (A) , (On I) , its acceleration is close to 100m/s2, and in the graph (C) , (E) , (on G) , the value is its acceleration respectively: 47, 64 with 78 M/s2, can see: Damp comparing change and photograph of change of electrode vibration curve are consistent, namely acceleration is big, damp comparing is tall; Additionally test data makes clear: The change of nucleus of spot welding frit is concerned with damp comparing, as the accretion of frit nucleus, damp comparing increases, when Dan Weirong nucleus and overheat, damp comparing has dash forward add, its electrode displacement is ambitious at form nucleus circumstance. Look from oscillatory frequency: Not frit nucleus and overheat the frequency of the correspondence of energy of the first the highest peak in a mountain range of two kinds of circumstances is taller, it is respectively: 1380Hz, 1394Hz, and frit nucleus area is mixed for 36 ％ , 70 ％ 92 ％ , it is 1367Hz, 1338Hz and 1166Hz respectively, progressively and degressive, frit nucleus area increases inherent and oscillatory frequency to show downtrend. Go up from recursive power chart from its look, graph (B) , (J) parts by two energy peak value, the specification is in spot welding process energy is relatively dispersive, lesser conform to adds up to this and energy of the first the highest peak in a mountain range, and graph (D) , (F) , (H) , have a Chan Feng only, with peak of the first energy taller result photograph agrees, and can you see: from inside the graph? Widow Pai a surname says the energy of part of? low frequency is in cerebral Ju to increase stage by stage, this specification greatens as frit nucleus, power chart also is in broaden. 4 conclusion electrode is containing the information that vibration of spot welding machine and frit nucleus form in acceleration data, through building electrode vibration equation is opposite in this research its undertake mode is analysed, this is a kind of new trial, the result that test and verify experiments shows its result is favorable, it to identifying the formation of frit nucleus further the process has certain direct effect, because study the job just begins originally, still must undertake much work will seek the rule further; In addition the result of the experiment still makes clear: The mode parameter of electrode vibration, wait like damp comparing, oscillatory frequency and peak value of the first energy, the feature that can change as nucleus of the frit in process of aluminium alloy spot welding is measured, but the relation dispute of they and frit nucleus area is linear, when building function to concern, need is done nonlinear processing. CNC Milling CNC Machining