Odd a machine medium application is measured in force of cutting of numerical control lathe

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The article introduced to use AT89C51 sheet piece machine the new method that measures power of cutting of numerical control lathe, the key elaborated sheet piece machine implementation is successive and automatic the method of commutation of changeover of sampling, A/D, scale and data processing. The article gave out odd a machine measure the principle that controls a system, structure and the partial program that undertake data is collected. Of 1 problem in offerring the treatment in numerical control lathe, the measurement of cutting force is attached most importance to very should. The measurement that carries pair of cutting power is OK the circumstance getting power of each component, orgnaization or structure mixes analysis and lathe of research numerical control working status, test and verify designs the validity with computational result, the mechanism of the laden chart in deciding whole mechanic makes a process and certain physics phenomenon. Accordingly, he is academic to developing a design, make sure ground of on the safe side of numerical control machine tool moves and machine tool of implementation numerical control detects automatic treatment, automatically, automata and cutting force overload call the police the effect with wait to be had very main and applicable value. The block diagram of principle of design system hardware of circuit of interface of 2 systems hardware is shown 1 times like the graph. System with AT89C51 sheet piece machine to control core, periphery circuit is aimed at sheet piece the functional characteristic of machine and design, made full use of AT89C51 is odd a machine piece inside resourceful characteristic, simplified periphery circuit, raised dependability. In the system is being confronted below main function module and analysis of one by one of hardware dependability technology. Graph block diagram of principle of 1 system hardware 2.

1 cutting join forces and component of force are measured to facilitate and study for the purpose of of force of cutting of numerical control lathe, in be being produced to suit especially, be designed and use the need of numerical control machine tool, cutting tool and clamping apparatus, decompose Fr of total cutting force into the force of 3 mutual and perpendicular direction commonly, namely Fz, Fy, Fx will consider. 2.

The most commonly used 2 sensor in measuring force transducer to measure power instrument normally are resistor silk meet an emergency piece with piezocrystal. The anise annulus that we design measures power instrument is meet an emergency of silk of a kind of resistor piece the appearance measuring power of type. The anise annulus that its job principle is the appearance that measure power is stretch component, meet an emergency of stickup on the wall of inside and outside of annulus resistor piece, form 3 bridge to determine in order to regard as repeatedly X, Y, Z3 the sensor of directional cutting force, when turning of numerical control lathe, workpiece roll delivers turning force classics to go up at lathe tool, deliver anise annulus by lathe tool arbor again, of anise annulus be out of shape make clingy the resistor meet an emergency on its piece also be out of shape subsequently, resistance R produced change (R of R ± Δ ) . When meet an emergency piece when sufferring drawing, attenuate of resistor silk diameter, resistance increases (R+ Δ R) , when meet an emergency piece press press shrinks when be out of shape, resistor silk diameter coarsens, resistance decrescent (R- Δ R) , output signal of direct proportion report thereby. The experiment is informed, as a result of resistor meet an emergency piece resistor change is very little, must magnify signal so 0, input of the ability after 5V is odd control system undertakes a machine be handled accordingly. Resistor meet an emergency piece compositive bridge is shown 2 times like the graph. A) graph is wait for circuit of brachial complete bridge, b) graph is horizontal half bridge circuit. Graph 2 resistor meet an emergency piece compositive bridge pursues 2 in for A) resistor meet an emergency piece the resistor that comprises bridge R1, R2, R3, R4 is arm of 4 bridge bridge respectively. When the bridge with try certain when end of A, C presses U criterion the output voltage U that B, D carries gets by next type: (1) by type (1) knowable, when R1R3=R2R4, bridge outputs voltage Δ U=0, namely bridge is in a balance, the adjustment that the bridge that this must undertake before undertaking cutting force is measured namely balances works. Below the action of cutting force, meet an emergency piece resistor happening changes, destroyed the equilibrium of bridge. If R1, R2, R3, R4 produces the resistor of R4 of R3 of R2 of Δ R1, Δ , Δ , Δ respectively,change, criterion by type (1) the output voltage of bridge is: (2) by type (2) a value that can see bridge is qualitative, when bridge photograph adjacent two arms have a sign when identical resistor changes, bridge outputs the result that voltage changes to be decreased for two bridges resistor. Accordingly, when the appearance that measure power receives the bridge, to make bridge has bigger output, should make two arms have bridge photograph neighbour the resistor with contrary symbol changes, and have the change with same symbol relative to two arms. This measures power instrument cloth originally namely piece the principle at receiving the bridge. The bridge with the commonly used appearance that measure power has wait for brachial complete bridge (bridge is comprised by 4 arms, r1=R2=R3=R4) reach half bridge (bridge adds composition of on two fixed resistor by two arms, r1=R2=R) , if pursue,2 are shown. By type (2) the output voltage of two kinds of bridge is: Complete bridge: R4) of Δ of R3- of Δ of R2+ of Δ of R1- of Δ U=U/4R(Δ (3) half bridge: R2) of Δ of R1- of Δ U=U/4R(Δ (4) quite (3) and (4) knowable, when R of Δ of R4=- of Δ of R2= of Δ of R; of Δ of R3=+ of Δ of Δ R1= , double what the output of complete bridge is half bridge, also namely double what the sensitivity of complete bridge is half bridge. Accordingly, measure the sensitivity of power instrument to rise, namely bridge has bigger output, we used those who wait for brachial complete bridge to measure circuit when the design measures power instrument. 2.

The signal that 3 span amplifier outputs sensor is µv commonly, Mv class, the unified n that enlarge can receive to modulus converter 0, 5V. 2.

4 multichannel switch is linked together the each telegraphic date after be being alternated by sensor in process of cutting of numerical control lathe and A/D, so that undertake A/D is changed, can save facility already so, unapt make compete each other between each parameter that be measured. The passageway date that multichannel switch closes every time by programme controll. 2.

The cutting power that because spot place is measured,5 sampling retain circuit is successive change, and odd piece machine sampling is spiccato however, to make parameter not by original numerical value still can be maintained when sampling, so need increases one sampling to maintain circuit, we used LF398 of chip of circuit of large scale integration. 2.

6A/D converter turns the imitate voltage that measures force transducer output into digital amount, what we choose is ADC0809 8 A/D converter, his changeover method is trial and error. Wave of behead of a tall impedance is contained to stabilize comparator in the interior of A/D converter, one contains the 256R voltage divider of imitate switch array, and a register that approachs line by line. 8 imitate switch can be locked up by the address implement control with encoder, can visit an unilateral imitate signal arbitrarily in 8 access. 2.

Although converter of A/D of force of 7 indication cutting is worth the imitate voltage that measures force transducer output changeover to be measured for the number, but the value that it is not force of cutting of lathe of effective numerical control, the value that should get real cutting power still needs to undertake the following two paces work: Static demarcate and scale alternate. Static demarcate: Build through the experiment namely measure force transducer to export the relation curve between voltage and cutting force and mathematical model. Scale commutation: The 00H after changing A/D converter namely, FFH number amount changes the value that is real cutting power again. Two paces job undertakes above the ability after ending is in odd a value that the cutting strength with numerical control real lathe shows on machine LED. So that numerical control lathe operates personnel,undertake monitor and administrative manufacturing waiting. The main program block diagram of system of design of 3 systems software sees a picture 3, systematic software includes: Dynamic indication process, A/D sampling program, scale commutation program and interrupt service program to wait. Suspending service program basically is the markers that uses timer to interrupt generation, to LED number the canal undertakes dynamic refresh shows. 3.

1This program cent main program mixes A/D sampling program suspend service program two parts. The main program is used to interrupting initialization, start the pulse, address that sends imitate quantity inside story, trends to show to ADC0809 hair, monitoring calls the police etc. Interrupt service program to measure and judge sampling to finish with the number after receive A/D to change deny. Graph block diagram of 3 systems main program pursues part of block diagram of subprogram of 4 scale commutation consults the program is as follows: Main program: ORG 0A00H MOV R1, #30H; Data-in area is initiative address MOV R4, #03H; Imitate measures total a movement in martial arts to send R4 MOV R2, #00H;IN0 address sends R2 SETB EA SETB EX0 SETB IT0 MOV R0, #0F0H MOV A, r2 MOVX @R0, a SJMP $ ; waits to interrupt suspend service program: ORG 0003H AJMP CINT1 ORG 0100H CINT1: MOV R0, #0F0H MOVX A, @R0 MOV @R1, a INC R1 INC R2 MOV A, r2 MOVX @R0, a DJNZ R4, LOOP; If did not collect 3, turn LOOP CLR EX0; If collect 3, close INT0 to interrupt LOOP: RETI END 3.

2 scale alternate subprogram block diagram is informed by experimental result, the value of the digital volume that this system changes by A/D and force of cutting of numerical control lathe shows linear concern. Accordingly, the mathematical formula that scale alternates is: The number of correspondence of place of floor level of appearance of ─ of ─ of N0 of real measured value measures the ─ of ─ of upper limit Ax that ─ of ─ of Ax=A0+(Am-A0)(Nx-No)/(Nm-No) A0 measures the ─ of ─ of floor level Am of appearance to measure meter the number of correspondence of place of upper limit of appearance of ─ of Nm ─ estimates measured value of ─ of Nx ─ , general the start A0 the parameter that be measured (input signal is 0) the A/D changeover value of place correspondence is 0, namely N0=0, such formula turn into: Block diagram of subprogram of commutation of scale of Ax= Nx/Nm(Am-A0)+A0 this system is shown 4 times like the graph. 4 last word application are odd a machine measure power of cutting of numerical control lathe, in realizing manufacturing process, successive and automatic sampling, real time shows, overload calls the police, so that operate personnel to undertake monitoring and management are produced, because cutting dosage passes,prevented effectively big and the phenomenon of lathe of damage numerical control happens. This system also but classics the application in the other sphere that after improving, transplants to need to be restricted to carry. CNC Milling CNC Machining