CN102806513A - Polishing method with constant grinding amount - Google Patents

Abstract

The invention discloses a polishing method with a constant grinding amount. The method comprises the following steps: (1) generating process codes which can be identified by a motion controller according to the pattern profile of a work piece to be polished, setting a grinding amount for polishing, which is expressed in the form of drive current I0 on a servo-amplifier, and enabling the motion controller to perform polishing treatment on the work piece according to the identifiable process codes; (2) during the polishing process, enabling the motion controller to read a drive current signal of the servo-amplifier and to re-correct the process path. According to the invention, the drive current of the servo-amplifier is used as the feedback input for real-time correction of the process path, so as to compensate the wear damage of the grinding wheel and ensure constant grinding amount during polishing. The polishing method with constant grinding amount has the advantages of simple principle and convenience for implementation, and has broad application prospects in polishing of fragile materials such as glass ceramics and the like.

Description

A kind of finishing method of permanent stock removal

Technical field

The present invention relates to the deep working method field of hard brittle materials such as glass, pottery, stone material, especially relate to the finishing method of realizing permanent stock removal in a kind of polishing process.

Background technology

For hard brittle materials such as glass, pottery, stone materials, the mode of wheel grinding is adopted in its deep processing more.And emery wheel carries out the subject matter of grinding is the emery wheel easy abrasion; Along with the increase of wear extent causes constantly dwindling of emery wheel operating radius; If can not effectively compensate to abrasion of grinding wheel; Will certainly cause the active force of emery wheel and material to change, thereby cause the inhomogeneous of stock removal, influence machining accuracy.The method of common abrasion of grinding wheel compensation is mainly the monitoring grinding wheel radius, in wheel grinding processing, constantly measures grinding wheel radius, imports digital control system then and adopts the mode of cutter radius compensation to compensate.In addition, the emery wheel size after in form grinder, usually adopting emery wheel regularly the mode of finishing obtaining to repair, it is identical that its essence and work in-process are constantly measured the mode that grinding wheel radius compensates.

Publication number is that the Chinese invention patent application of CN 101733705A discloses a kind of abrasion of grinding wheel detection and compensation method automatically; Emery wheel after adopting dresser to grinding is revised circulation automatically; Adopt the grinding wheel diameter detector that the grinding wheel diameter data that the grinding wheel diameter in the processing carries out online detection, the acquisition of detection back are sent to digital control system; Digital control system is compared the grinding wheel diameter data with original grinding wheel diameter data; Obtain abrasion of grinding wheel amount and emery wheel correction, thereby the depth of cut of digital control system control lathe realizes the automatic compensation of emery wheel.

Publication number is that the Chinese invention patent application of CN 101434054A discloses a kind of processing method that realizes error compensation of abrasion wheel; May further comprise the steps: confirm that 1) cup type grinding wheel trimming device as the machining tool that emery wheel is carried out correction of the flank shape, carries out online finishing with cup type grinding wheel trimming device to the diamond arc diamond wheel; 2) the crushing system is designed; 3) utilize the crushing system that emery wheel is carried out on-line measurement; 4) handle the data of measuring gained with the method for the filtering of radius constraint initial data, radius least square fitting, draw compensation control point; 5) programming and generation NC program, the processing compensation of grinding wheel error is accomplished in the operation of control process equipment.

Above-mentioned two patent applications all adopt the method for measuring grinding wheel radius to carry out the compensation of abrasion of grinding wheel; The compensation that the method for work in-process measurement grinding wheel radius is carried out abrasion of grinding wheel has bigger limitation; Be suitable for wear extent and change grinding process slowly; Simultaneously repeatedly the measurement grinding wheel radius or regularly the method for trimming wheel size can cause process to be interrupted, working (machining) efficiency reduces.When carrying out glass polishing as the glass processing medium plain emery wheel, emery wheel adopts the resin wheel, and the wear extent of resin wheel is very big, and 0.1mm even more can wear and tear on 1 meter processing length.And in process, require the polished amount of each position identical in order to reach desirable polishing effect; Process also can't be interrupted; Thereby press for a kind of automatic compensation that can realize the wearing and tearing of polishing process medium plain emery wheel, thereby realize the permanent stock removal of polishing process.

Summary of the invention

The invention provides a kind of finishing method of permanent stock removal,, machining locus is revised in real time, thereby the compensation abrasion of grinding wheel is realized the polishing of permanent stock removal through the drive current of servo amplifier is imported as feedback.

A kind of finishing method of permanent stock removal may further comprise the steps:

The graph outline that 1) will polish according to workpiece generates the discernible machining code of motion controller, sets polishing stock removal size, with the drive current I on the servo amplifier ₀Expression, motion controller begins polishing processing according to the discernible machining code of motion controller to workpiece;

2) in the polishing processing, motion controller reads the driving current signal of servo amplifier, and machining locus is revised again;

Specifically comprise: motion controller is at servo period T _iRead the drive current I of servo amplifier _i, the position of establishing current emery wheel center is P _i(X _i, Y _i), the moving target point position at next emery wheel center is P _I+1(X _I+1, Y _I+1):

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), wherein, $\mathrm{\&Delta;}{X}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{Y_{i+1}-Y_i}{L_i}\right),$ $\mathrm{\&Delta;}{Y}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{X_{i+1}-X_i}{L_i}\right),$ $\mathrm{\&Delta;}{R}_i=K_1{E}_i+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="HDA00002011300400011.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k+K_3(E_i-E_{i-1}),$ Δ R _iBe abrasion of grinding wheel amount, K ₁, K ₂And K ₃Be pressure compensation adjustment factor, P _iPoint servo amplifier current error E _i=I ₀-I _i, P _iP before the point _I-1Point servo amplifier current error E _I-1=I ₀-I _I-1, wherein, I _I-1Be P _I-1The drive current I of the servo amplifier that point reads _I-1,

For running to P _iThe error sum of point, P _iP _I+1The straight path segment length $L_i=\sqrt{{(X_i-X_{i+1})}^2+{(Y_i-Y_{i+1})}^2}.$

In the step 1), the motion of polishing cutter (being emery wheel) in the workpiece processing plane realizes moving of X, Y direction by motion controller control polishing machining tool, thus the amount of feeding of control polishing cutter.

The discernible machining code of motion controller adopts as NC (Numerical Control, digital control, abbreviation numerical control) code, is also referred to as G code usually.

Because the drive current on the servo amplifier and the load of spindle motor have direct relation, thereby the polishing stock removal can will polish stock removal and be designated as I through the next directly sign of the drive current on the servo amplifier ₀

The polishing stock removal requires to confirm final polishing stock removal based on glass processing thickness, the speed of mainshaft, grinding wheel characteristics, quality of finish, can artificially set.

The main shaft that processing is used is servo principal axis, and by the servo amplifier drives spindle motor, the spindle motor rotation drives emery wheel rotation synchronously workpiece is polished, and servo amplifier is controlled by motion controller.

Step 2) in,

For from machining starting point P ₁Run to P _iThe error sum of point is promptly at servo period T ₁Read the drive current I of servo amplifier ₁, at servo period T ₂Read the drive current I of servo amplifier ₂At servo period T _iRead the drive current I of servo amplifier _i, $\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k=(I_0-I_1)+(I_0-I_2)......+(I_0-I_i).$

Pressure compensation adjustment factor K ₁, K ₂, K ₃Generally according to machining tool and practical operation adjustment, general K ₁=0.01 ~ 0.1, K ₂=0.02 ~ 0.2, K ₃=0.04 ~ 0.4, as when gantry machine tool is processed the non-conventional glass workpiece, can specifically select K ₁=0.05, K ₂=0.1, K ₃=0.2.

Compared with prior art, the present invention has following advantage:

The finishing method of the permanent stock removal of the present invention adopts this drive current to characterize the size of stock removal in the polishing process through the drive current in the servo amplifier is monitored.In servo period with current drive current and target current (the drive current I that promptly sets ₀) compare, calculate the wear extent of emery wheel, can obtain the coordinate amount of bias of next section tracing point according to the wear extent of emery wheel, make emery wheel and workpiece keep constant stock removal, thereby realize permanent stock removal polishing.The finishing method of the permanent stock removal of the present invention has advantages such as principle is simple, realization is convenient, in the polishing of fragile materials such as glass ceramics, has a wide range of applications.

Description of drawings

Fig. 1 is the schematic diagram of the finishing method of the permanent stock removal of the present invention;

Fig. 2 is the drive current distribution map of the servo amplifier in the 13min after the finishing method of the permanent stock removal of employing the present invention among the embodiment 1 begins grinding.

The specific embodiment

As shown in Figure 1, be the schematic diagram of the finishing method of the permanent stock removal of the present invention.Emery wheel 2 is in the process of polishing along workpiece 1 peripheral profile, because the quick wearing and tearing of emery wheel 2 can cause the stock removal of emery wheel 2 to reduce gradually.In order to guarantee the constant of emery wheel 2 stock removals, need in servo period, revise the track of emery wheel 2, compensation emery wheel 2 wear extenies can realize the polishing process of permanent stock removal.Shown in Fig. 1 (a), the graph outline that will polish according to workpiece 1 generates the discernible machining code of motion controller, like NC code (the discernible code of motion controller a kind of).The motion of emery wheel 2 in workpiece 1 processing plane realizes moving of X, Y direction, the amount of feeding of control emery wheel by motion controller control polishing machining tool.The main shaft that processing is used in the lathe is servo principal axis, and by the servo amplifier drives spindle motor, spindle motor drives emery wheel 2 rotations through main shaft workpiece 1 is polished.Servo amplifier is controlled by motion controller.Require to confirm final polishing stock removal according to glass processing thickness, the speed of mainshaft, grinding wheel characteristics, quality of finish, set polishing stock removal size, with the drive current I on the servo amplifier ₀Expression, because the drive current on the servo amplifier and the load of spindle motor have direct relation, thereby the polishing stock removal can will polish stock removal and be designated as I through the next directly sign of the drive current on the servo amplifier ₀Shown in Fig. 1 (b), be the original motion track (before promptly revising) 23 of emery wheel 2, if the original motion track is not revised, then the position at emery wheel 2 centers 21 will be from P _i(X _i, Y _i) to move to the impact point position along original motion track 23 be P _I+1(X _I+1, Y _I+1), arrow 22 is the normal of emery wheel 2.Shown in Fig. 1 (c), for movement locus 24 after the compensation of emery wheel 2 (promptly revising the back), with impact point position P _I+1(X _I+1, Y _I+1) be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), detailed process is following:

Motion controller is at servo period T _iRead the drive current I of servo amplifier _i, can read the driving current signal of servo amplifier through AD conversion (analog quantity becomes the digital quantity conversion) module, servo period is the position that motion controller reads emery wheel 2 centers 21, thus the cycle that next step movement position is proofreaied and correct;

If the position at current emery wheel center is P _i(X _i, Y _i), the moving target point position at next emery wheel center is P _I+1(X _I+1, Y _I+1);

P _iPoint servo amplifier current error: E _i=I ₀-I _i, P _iP before the point _I-1Point servo amplifier current error: E _I-1=I ₀-I _I-1, wherein, I _I-1Be P _I-1The drive current I of the servo amplifier that point reads _I-1,

For running to P _iThe error sum of point is promptly at servo period T ₁Read the drive current I of servo amplifier ₁, at servo period T ₂Read the drive current I of servo amplifier ₂At servo period T _iRead the drive current I of servo amplifier _i, $\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k=(I_0-I_1)+(I_0-I_2)......+(I_0-I_i);$

P _iP _I+1The straight path segment length: $L_i=\sqrt{{(X_i-X_{i+1})}^2+{(Y_i-Y_{i+1})}^2};$

Unit vector be: $(\frac{X_{i+1}-X_i}{L_i},\frac{Y_{i+1}-Y_i}{L_i});$

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), wherein, $\mathrm{\&Delta;}{X}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{Y_{i+1}-Y_i}{L_i}\right),$ $\mathrm{\&Delta;}{Y}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{X_{i+1}-X_i}{L_i}\right),$ $\mathrm{\&Delta;}{R}_i=K_1{E}_i+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="HDA00002011300400011.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k+K_3(E_i-E_{i-1}),$ Δ R _iBe abrasion of grinding wheel amount, K ₁, K ₂, K ₃Be the pressure compensation adjustment factor.

Pressure compensation adjustment factor K ₁, K ₂, K ₃Generally according to machining tool and practical operation adjustment, general K ₁=0.01 ~ 0.1, K ₂=0.02 ~ 0.2, K ₃=0.04 ~ 0.4.

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i) afterwards; Motion and the control servo amplifier of motion controller control emery wheel 2 in workpiece 1 processing plane; By the servo amplifier drives spindle motor, spindle motor drives emery wheel 2 rotations through main shaft workpiece 1 is polished, and makes the center 21 of emery wheel 2 move to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), thereby machining locus is revised in real time, thus 2 wearing and tearing of compensation emery wheel realize the polishing of permanent stock removal.

Embodiment 1

Periphery to the special-shaped glass workpiece carries out permanent stock removal polishing; The structure of lathe is a planer-type; The special-shaped glass workpiece is fixed on the work top of lathe, and main shaft is installed on the Z axle, and the integral installation of Z axle is on crossbeam X axle; And crossbeam X axle is located on the Y axle through guide rail bracket, and crossbeam X axle can move on the Y axle along guide rail.The Z axle is used to regulate the grinding height, and motion controller control X axle and Y axle diaxon move around special-shaped glass, polish.Servo amplifier drives main axis rotation through spindle motor, and the drive current of servo amplifier inserts in the motion controller through 10 tunnel AD modular converter.Under Light Condition, the drive current of servo amplifier is 5A, and the drive current of servo amplifier is 8A under the normal process state.Motion controller adopts the mode of built-in industrial control machine+motion control card to carry out the motion control of lathe.

(a) graph outline that will polish based on the special-shaped glass workpiece; Generate the discernible NC code of motion controller; It is that the Circular glass of 500mm polishes processing to its periphery that the special-shaped glass workpiece is selected diameter for use, adopts general NC code to generate software CAXA software and obtains the required NC code of processing;

(b) require to confirm final polishing stock removal according to special-shaped glass workpiece processing thickness, the speed of mainshaft, grinding wheel characteristics, quality of finish, set polishing stock removal size, with the drive current I on the servo amplifier ₀Expression.Through comparing the polishing effect of special-shaped glass workpiece under the different driving electric current, finally selecting drive current for use is I in the present embodiment ₀=8A;

(c) motion controller begins polishing processing according to the NC code;

(d) in the polishing process, motion controller reads the driving current signal of servo amplifier, and machining locus is revised again, and detailed process is following:

Motion controller is at servo period T _iRead the drive current I of servo amplifier _i, can read the driving current signal of servo amplifier through AD conversion (analog quantity becomes the digital quantity conversion) module,

If the position at current emery wheel center is P _i(X _i, Y _i), the moving target point position at next emery wheel center is P _I+1(X _I+1, Y _I+1);

P _iPoint servo amplifier current error: E _i=I ₀-I _i, P _iP before the point _I-1Point servo amplifier current error: E _I-1=I ₀-I _I-1, wherein, I _I-1Be P _I-1The electric current I of the servo amplifier that point reads _I-1,

For running to P _iThe error sum of point;

P _iP _I+1The straight path segment length: $L_i=\sqrt{{(X_i-X_{i+1})}^2+{(Y_i-Y_{i+1})}^2};$

Unit vector be: $(\frac{X_{i+1}-X_i}{L_i},\frac{Y_{i+1}-Y_i}{L_i});$

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), wherein, $\mathrm{\&Delta;}{X}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{Y_{i+1}-Y_i}{L_i}\right),$ $\mathrm{\&Delta;}{Y}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{X_{i+1}-X_i}{L_i}\right),$ $\mathrm{\&Delta;}{R}_i=K_1{E}_i+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="HDA00002011300400011.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k+K_3(E_i-E_{i-1}),$ Δ R _iBe abrasion of grinding wheel amount, K ₁, K ₂, K ₃Be the pressure compensation adjustment factor.Pressure compensation adjustment factor K ₁=0.05, K ₂=0.1, K ₃=0.2.

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i) afterwards, motion and the control servo amplifier of motion controller control emery wheel in processing plane, by the servo amplifier drives spindle motor, spindle motor drives the emery wheel rotation through main shaft workpiece is polished, and makes the center of emery wheel move to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), thereby machining locus is revised in real time, thus the compensation abrasion of grinding wheel is realized the polishing of permanent stock removal.In order to detect permanent stock removal polishing effect, having write down diameter is the drive current size of the servo amplifier of Circular glass when polishing of 500mm.Fig. 2 distributes for the drive current that formally begins the servo amplifier in the 13min after the grinding.Because the drive current on the servo amplifier and the load of spindle motor have direct relation, thereby the polishing stock removal can directly characterize by the drive current on the servo amplifier.As shown in Figure 2, the drive current of servo amplifier distributes more even, has kept constant stock removal, thereby realizes permanent stock removal polishing.

Claims (2)

1. the finishing method of a permanent stock removal may further comprise the steps:

The graph outline that 1) will polish according to workpiece generates the discernible machining code of motion controller, sets polishing stock removal size, with the drive current I on the servo amplifier ₀Expression, motion controller begins polishing processing according to the discernible machining code of motion controller to workpiece;

2) in the polishing processing, motion controller reads the driving current signal of servo amplifier, and machining locus is revised again;

Specifically comprise: motion controller is at servo period T _iRead the drive current I of servo amplifier _i, the position of establishing current emery wheel center is P _i(X _i, Y _i), the moving target point position at next emery wheel center is P _I+1(X _I+1, Y _I+1);

With P _I+1(X _I+1, Y _I+1) dynamically be modified to P ' _I+1(X _I+1+ Δ X _i, Y _I+1+ Δ Y _i), wherein, $\mathrm{\&Delta;}{X}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{Y_{i+1}-Y_i}{L_i}\right),$ $\mathrm{\&Delta;}{Y}_i=-\mathrm{\&Delta;}{R}_i\left(\frac{X_{i+1}-X_i}{L_i}\right);$ $\mathrm{\&Delta;}{R}_i=K_1{E}_i+K_2\underset{k=1}{\overset{k=i}{\mathrm{\&Sigma;}}}{E}_k+K_3(E_i-E_{i-1}),$ Δ R _iBe abrasion of grinding wheel amount, K ₁, K ₂And K ₃Be pressure compensation adjustment factor, P _iPoint servo amplifier current error E _i=I ₀-I _i, P _iP before the point _I-1Point servo amplifier current error E _I-1=I ₀-I _I-1, I _I-1Be P _I-1The drive current I of the servo amplifier that point reads _I-1,

For running to P _iThe error sum of point, P _iP _I+1The straight path segment length $L_i=\sqrt{{(X_i-X_{i+1})}^2+{(Y_i-Y_{i+1})}^2}.$

2. the finishing method of permanent stock removal according to claim 1 is characterized in that, K ₁=0.01 ~ 0.1, K ₂=0.02 ~ 0.2, K ₃=0.04 ~ 0.4.

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