Machine tool of shallow analyse numerical control processes the account of loss of accuracy
- source:NEWRGY CNC Machining
First exterior hind machine tool of internal numerical control is market mechanism, hydraulic pressure, electric the machine tool that is an organic whole, the happening of its breakdown also meets friend by this 3 person comprehensive report comes out. Maintenance technician should be undertaken discharging checking by the one by one inside extroversion first, avoid optional ground open the envelop as far as possible, disassemble, can enlarge breakdown otherwise, make the machine tool loses precision, reduce performance. 2.
First machinery hind is electric generally speaking, mechanical failure detects more easily, and the diagnosis of breakdown of numerical control system criterion somes difficulty is greater. Before corrective maintenance, notice to remove mechanical trouble above all, often can achieve the result of get twice the result with half the effort. 3.
Below the dormant position that preexistence machine tool uses to cut off the power after Xian Jing, pass understanding, observation, test, analysis, think truly after nondestructive breakdown, just can give a machine tool electrify; Below operating conditions, have dynamic observation, examine and check, search breakdown. And to ruinous breakdown, after must eliminating risk first, square but electrify. 4.
First simple hind complex should appear a variety of breakdown interweave each other mask, when doing not know how to start temporarily, answer to solve easy problem first, the problem with bigger difficulty is solved after. After often asking the problem is solved simply, the question with big difficulty becomes possibly also easy. 3, of of of diagnostic method of breakdown of numerical control machine tool 1.
Direct way: (hope to hear ask cut) ask - the breakdown phenomenon of the machine tool, treatment state; Look - CRT calls the police information, call the police indicator light, the component such as capacitor is out of shape sootiness scorchs, protector is taken off buckle etc; Listen - unusual noise; Hear - flavour of electric component anxious paste and other peculiar smell; Feel - calorific, oscillatory, the contact is undesirable wait. 2.
Parameter examines a way: Parameter is to deposit normally in RAM, sometimes batteries voltage is insufficient, the system is illogical for a long time report or exterior interference can make parameter missing or confused, should according to breakdown feature, check and proofread concerned parameter. 3.
Keep apart a law: A few breakdown, distinguishing hard is numerical control part, still servo or mechanical part are caused, often use segregation method. 4.
Congener exchange law reserves with what be the same as a function board the pattern plate that replaces breakdown be havinged by suspicion, or the function identical pattern plate or unit are exchanged each other. 5.
Functional program checks law general G, m, s, t, full statement of the function writes a few small programs, these programs run when diagnostic breakdown, can judge a function be short of break. 4, unusual breakdown diagnoses treatment precision and handle of example 1.
Mechanical failure brings about treatment precision phenomenon of breakdown of unusual : Machining center of vertical of a SV-1000, use Frank system. In machining process of connecting rod mould, discover Z axis feed is unusual suddenly, cause at least the cutting margin of error of 1mm (Z direction is cut too) . Breakdown diagnoses: The understanding in investigation arrives, breakdown happens suddenly. The machine tool is moved in the dot, it is normal that each axes below data-in means operation are moved to move in the hand, and it is normal to wind reference point, do not have any calling the police to hint, the possibility of hard breakdown of electric control part eliminates. Answer to basically undertake checking to one by one of the following respects. The machine program that the examination is running when machine tool precision is unusual paragraph, especially compensation of cutting tool length, machining coordinate is (G54-G59) proofread and calculate. Means is moved to fall in the dot, move repeatedly Z axis, the course is inspected, touch, listen, to its athletic condition is diagnosed, discover Z to athletic noise unusual, nod quickly especially move, noise is more apparent. Judge from this, mechanical respect may be put in hidden trouble. Check precision of axis of machine tool Z. Shake with the hand pulse generator moves Z axis, (its fold is 1 × surely of 100 block, namely every change one pace, electric machinery feed 0.
1mm) , cooperate dial gauge to observe the athletic condition of Z axis. Serve as initial drop after one-way motion keeps normal to motion, pulse implement every change one pace, the actual distance D=d1=d2=d3= that axis of machine tool Z moves... =0.
1mm, explain electric accident travel is good, fixed position precision is good also. And return a machine tool on the change of virtual campaign displacement, can divide for 4 phase: (1) machine tool motion is apart from D1>d=0.
1mm (slope is more than 1) ; (2) show for D1=0.
1mm>d2>d3 (slope is less than 1) ; (3) machine tool orgnaization did not move actually, show most standard backlash; (4) distance of machine tool motion and pulse implement classics destiny value is equal (slope is equal to 1) , renew the normal campaign of the machine tool. No matter how undertake compensating to backlash, the trait that its show is: Besides (3) outside level compensation, other each paragraphs of change still occurs, especially (1) the treatment precision that level affects a machine tool badly. The discovery in compensation, clearance compensation is bigger, (1) the space with mobile phase is larger also. Analyse afore-mentioned examinations to think when to exist likelihood reason: It is electric machinery has unusual, 2 it is mechanical respect has trouble, 3 it is clearance of guide screw existence. To diagnose breakdown further, electric machinery and guide screw complete come away, undertake checking to electric machinery and mechanical part respectively. Checking a result is electric accident travel is normal; In the discovery in be being diagnosed to mechanical part, with the hand dish when moving guide screw, return motion initiative have very big vacant feeling. And below normal circumstance, can feel bearing is orderly and should move smoothly. Breakdown processing: Through disassembling the examination discovers this bearing is damaged really, and ball falls off. The machine tool after changing returns to normal. 2.
Control logistic misgivings to bring about treatment precision phenomenon of breakdown of unusual : The machining center that manufacturer of machine tool of a Shanghai produces, the system is Frank.
In machining a process, discover precision of axis of X of this machine tool is unusual, precision error is the smallest for 0.
008mm, most greatly 1.
Breakdown diagnoses: In the examination, the machine tool had set department of G54 workpiece coordinate according to the requirement. Data-in means operation is moved to fall in the hand, with G54 coordinate the department runs a paragraph of program namely " GOOG90G54X60.
OF150; M30; " , the mechanical coordinate value that indicates on the monitor after waiting for a machine tool to run an end is (X axis) " - 1025.
243 " , this are numeric below the record. Move means to fall in the hand next, the machine tool the dot uses other and aleatoric position, move data-in means to operate next moving in the hand again a moment ago block, after waiting for a machine tool to stop, numerical value of coordinate of the machine tool when discovering this shows for " - 1024.
891 " , the numerical value after be being carried out last time together differred quite 0.
According to same method, x rod the dot uses the position that moves to differ, carry out this block repeatedly, and the numerical value that indicates on monitor differs somewhat (not stable) . Undertake microscope to X axis with dial gauge, discover mechanical position is real the error shows with the number the error that come out agrees basically, think breakdown reason repeats fixed position error for X axis thereby too big. Undertake checking to the backlash of X axis and fixed position precision, compensate its error value afresh, any action are less than since the result. Because this suspects grating feet and systematic parameter,wait have a problem. But why to produce so big error, did not appear to call the police accordingly again however information checks discovery further, this axis is the axis of perpendicular direction, when X axis is loose main shaft box is down, caused an error. Breakdown processing: To the PLC of the machine tool control program did logic to revise, it is namely when X axis is loose, make X axis first can to load, loosen X axis again; And when X axis clamp, first X axis clamp hind, again make can take out. Breakdown of the machine tool after adjusting is able to solve. 3.
Problem of machine tool seat brings about treatment precision phenomenon of breakdown of unusual : The vertical CNC Milling that a Hangzhou produces, provide Beijing KND-10M system. In the dot is moved or machining a process, discover Z axis is unusual. Breakdown diagnoses: Check discovery, next shift on Z axis are inhomogenous and have noise, and put in certain clearance. When electric machinery is started, the noise that moves the motion on axial of the Z below means to exist to be not stabilized in the dot and get power inhomogenous, and sensory electric machinery shakes fiercer; And when moving downward, did not shake so apparently; When stopping, do not shake, behave more apparently in machining a process. The analysis thinks, breakdown reason has at 3 o'clock: It is guide screw backlash very big; 2 it is Z axis electric machinery the job is unusual; 3 it is damage of leather belt annulus comes get power not all. But those who a problem wants to notice is, when stopping, do not shake, fluctuation motion is inhomogenous, electric machinery job is so unusual this problem can eliminate. Because this is diagnosed to mechanical part first, unusual without discovery in diagnostic test process, it is in tolerancepublic errand. Use a platoon to eliminate rule, the rest of have strap problem only, detecting when leather belt, disclosure this leather belt just was changed before long, but in attentive detect when leather belt, discover leather belt inside appears the damage of different level, it is to get power apparently all be not reached, it is what reason cause discover in diagnose electric machinery is placed have a problem, the angle position asymmetry that holds clip namely is caused get power not all. Breakdown processing: As long as electric machinery reshipment, aim angle, measure good space (the bearing of electric machinery and Z axis) , leather belt both sides (length) want even. Such, next shift on Z axis are inhomogenous and noise is reached shake the phenomenon was eliminated, z axis treatment returns to normal. 4.
Systematic parameter was not optimized, electric machinery runs unusual to bring about treatment precision unusual system parameter basically includes unit of machine tool feed, slanted at 0 o'clock buy, backlash. For example system of Frank numerical control, its feed unit has metric and imperial two kinds. The process is repaired in the machine tool in to local treatment, often affect slanted at 0 o'clock the change of buy and clearance, after breakdown processing ends, should make timely adjustment and revise; On the other hand, because mechanical wear is serious or join a change that becomes loose to cause parameter actual measurement possibly also to be worth, need does corresponding modification ability to satisfy a machine tool to machine the requirement of precision to parameter. Breakdown phenomenon: The vertical CNC Milling that a Hangzhou produces, provide Beijing KND-10M system. In machining a process, discover X axis precision is unusual. Breakdown diagnoses: The examination discovers X axis is put in certain clearance, and the phenomenon with the not stable existence when electric machinery is started. With the feeling when the hand feels X axis electric machinery electric machinery is pulled move fiercer, when stopping, pull move not apparent, nod especially move means to fall more apparent. The analysis thinks, breakdown reason has at 2 o'clock: It is guide screw turns over clearance very big; 2 it is X axis electric machinery the job is unusual. Breakdown processing: Use the parameter function of KND-10M system, undertake debugging to electric machinery. Undertake compensating to the clearance of existence above all, readjust servo parameter and pulse restrain functional parameter, of X axis electric machinery shake eliminate, the machine tool machines precision to return to normal. CNC Milling CNC Machining