DE2442679C3 - Device for setting the relative position between tool and workpiece on processing machines - Google Patents

Description

_- The invention relates to a device of the im Generic term of claim 1 described genus /

In numerous machine tools for workpieces, there are particularly high requirements the speed as well as the accuracy of the Adjustment between workpiece and tool * The manufacturing processes are a clear example of this

for electronic circuit elements, where the dimensions of the progressive miniaturization of the individual components as well as the distances between the components and the conductors are getting smaller and smaller and with which accordingly on a single element an ever larger one Number of components is housed. Prerequisite for an economical production of the same Elements is therefore that the positioning of the workpiece in relation to the tool with the highest Precision and great speed can be performed.

By the US-PS 32 67 250 a device for controlling the relative position between a tool is and a workpiece in which, e.g. individual components of a microminiaturized element to meet the above requirements first the workpiece using an adjustable workpiece carrier, ζ. B. a table on a certain position is preset (coarse setting) in which a machining process is carried out shall be. Once the workpiece table has reached this position, preferably the deflection area of an electron beam device, the electron beam is then adjusted to the area of the element to be processed (fine adjustment).

Based on this prior art, the invention is based on the object of providing a device for Setting the relative position between the tool and the workpiece to create the setting with high Speed and with respect to a predetermined position, such as a reference point, with the highest achievable accuracy is feasible. This task is the introductory part of a facility mentioned training according to the invention by the in the characterizing part of claim 1 specified features solved.

Here, the invention makes itself, as in the prior art Technology, the respective mass ratios and adjustment options of workpiece and tool by initially making a coarse setting with that gill is carried out, which the has greater mass, while the other element, with the smaller one, is subsequently used for fine adjustment Mass, is changed, which accordingly also enables a more precise setting.

According to the invention, the relative position between the tool and the workpiece is already set the target position of the workpiece is specified in the coarse setting and by comparing the actual position with the Nominal position determines an error signal which is evaluated to control the actuator for the coarse setting will. After a predetermined limit value has been reached for the error signal, this takes place the fine setting of the tool or the Workpiece, depending on which carrier has the lower mass. This gives you the option of using Adaptation to the particularities of the workpiece, the machining process to be carried out and the Mutual masses and designs of the drives vary in the error signal tolerance range choose, depending on which border area is the most favorable for the two-stage housing The facility is therefore extremely flexible, which means that it can be used for a wide variety of workpieces And machining operations benefit.

An advantageous embodiment of the device according to the invention is that each motor of the A stop logic circuit is assigned to the workpiece carrier actuator, which is in operative connection with a stop switch which, when a stop condition occurs, feeds the error signal to the motor control loop interrupts

The standstill detector is preferably connected to the actual position value transmitter and determines the speed the change in position and, if the change in position is sufficiently slow, switches a fine gate switch from Coarse to fine adjustment.

If an electron beam that can be adjusted in position by means of electrical deflection devices is used as a tool, so, according to a preferred embodiment of the invention, the electrical deflection devices can be influenced by the residual error signals when the standstill detector responds.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing. explained.

It shows

Fig. 1 is a block diagram of a device for setting the relative position between the tool and Workpiece.

F i g. 2 the assembly of the F i g. 2A, 2B and 2C,

Fig. 2A. Figures 2B and 2C are a detailed block diagram the device according to FIG. 1,

F i g. 3 is a partial side view of a work table drive in the X and / direction, jo

F i g. 4 the partial view of a tool carrier,

F i g. 5-15 circuit details from FIG. 2.

The F i g. 1 shows a first element or tool 10, which is arranged opposite a second element or workpiece, which is on a workpiece carrier. hereinafter referred to as coordinate table 11, is located. The coordinate table 11 is driven by motors 12 and 13, which according to a ν m of a control unit 100 to control it position address outputted. The X coordinate of the address of the machining position on the workpiece W is fed to the yY servo circuit 20 via the line 101 and the / coordinate is fed to the V servo circuit 103 via the line 102. The information about the actual position value comes back to the se.vocircuits via 4, feedback lines 204 and 1034. A speed feedback takes place via lines 124 and 134.

The servo circuits 20 and 103 are set so that the motors 12 and 13 are stopped as soon as the workpiece W is within a predetermined tolerance range, ie when the follow-up error, the difference between the target value and the actual value, has become sufficiently small.

The rather small error that remains after that will be - ,, fed to the tool controls 75 and 104, which cann adjust the tool 10 so that it with respect to the workpiece is just right.

Since the elements of the two coordinate directions necessary for positioning correspond completely to one another, it is sufficient to describe only the elements of a coordinate.

Part of the coordinate table 11 is shown in FIG shown, the table consists of an upper platform 114 and a lower platform 115, the Platform 115 is permanently mounted on a drive 14. This drive includes a motor 12 which rotates shaft 125 and thereby movement in that direction 144 'causes. The platform 114 is similar Manner connected to the motor 13, which in turn is mounted on the platform 115 and the platform 114 in with respect to the platform 115 in the direction 115 'perpendicular to the plane of the drawing. Of the drive described can be formed by any type of cross table, which is through the Purpose of use given requirements for stiffness, play, inertia, resonance etc. are met

The tool 10 of FIG. 1 initially consists of the one shown in FIG. 4, which in the present example has a drill chuck 18 with a clamped drill 184, which is to be precisely adjusted with respect to the workpiece W arranged on the coordinate table 11. The micro-positioning table 15 consists of a frame 154 which can be moved by known means, both vertically, so that the drill bit on the workpiece W engages, and horizontally, and this both with a can be done ¹ manually or automatically in T ig 4 is the chuck 18 mounted on a plate 2 which is suspended in the frame 154 by leaf springs 1. The leaf springs transmit a high force in the direction of the Z-axis and far lower but equal forces in the direction of the X- and Y-axes. The plate 2 can be moved by drive elements 4 and 5 in the frame proportionally to the force exerted by them.

The .Y servo circuit 20 first compares the desired position of the workpiece W with the actual one and moves the coordinate table 11 until the workpiece reaches the desired position, hereinafter referred to as "position", with a certain tolerance, and then enters the remaining error ( Residual error) to the A "tool control 75. As a result, the tool is precisely positioned with respect to the workpiece.

F i g. In box 21, FIG. 2C shows the table drive with the motor 12. The tachometer 22 belongs to the motor 12, the can form a unit with this and via the Leiturg 124 a speed signal to the Speedometer amplifier 224 outputs. The amplified speedometer signal is sent to motor driver 23 via line 125 returned. The motor amplifier 24, which is controlled by the motor driver 23, guides the motor 12 The power required for operation is supplied via line 244 and thus closes the servo control circuit. The drive 21 can also be referred to as a servo drive with tachometer damping.

Ah tacho amplifier is used by an operational amplifier which is adapted in such a way that it eliminates the disturbances that for example generated by collector brushes, suppressed and a voltage signal that the motor speed is proportional, gives off. The signal is supplied to the motor driver 23 so that this rr depending on the signal present on the line 234 increases or decreases its output signal.

The position signal on line 234 can, if necessary, be interrupted by a f.op switch 25 and thus the motor can be stopped. The stop switch 25 is an ordinary on / off switch.
= Connect with the stop switch 25 :! is a bandstop filter 26 to which the position signal is fed via line 264, which signal passes through the bandstop filter 26 and the stop switch 25. The band stop filter 26 suppresses the natural resonance of the ΛΎ drive. If, for example, the table has a resonance at 50 Hz, the band plug filter 26 is set for an amplitude minimum at this frequency.

The position signal can be fed to the -Y-Sefvökreis 20 per se in analog or digital form. The high precision of the digital representation should be preferred here. Therefore it is necessary to convert the signal for the motor from digital to analog part. This is done in the digital / analog converter 27, FIG. 2B. The converter receives a digital signal in binary coded bezimaldarsiellung, which is the difference; represents between the desired and the actual position of the tool carrier. It converts the signal into analog form and forwards it to the function generator 28 on line 21B. The function generator, which generates a square root function, differentiates the position difference signal, which indicates the distance over which the servo controller is to move the table. The function generator 28 thus receives an iranaccnannilno CÜS dsf ΕΠίΓαΓΓϊΙ ^ Π ' ¹ ' ZWiSChsfi dwf the target position and the actual position of the table at any time. The first derivative of a position with respect to time is the speed. Since it is advantageous to maintain a constant acceleration when starting and braking the table, the square root function is used in the function generator 28 so that the speed is controlled as a function of the distance and not as a function of time.

The square root function generator behaves satisfactorily in the present exemplary embodiment, because the drive's inherent time constant helps with sudden changes at start, middle and To dampen the end of a step. (This drive impulse function has been described in the literature on drive cams discussed in detail, see Cams Design, Dynamics, and Accuracy by H. A. Rothbart, John Wiley & Sons Inc., New York, 1956, Chapter 2. The text deals with the parabolic function of the Square root and with the more suitable cycloid.)

The output of the function generator 28 leads to a control amplifier 29 which the to the bandstop filter 26 and thus the signal supplied to the motor driver 23 is limited. The control amplifier 29 is on the desired gain set, for example by the control unit 100 via the line 29/4, if the Coordinate table 11 approaches the desired position. Three conditions exist under which a stop signal is supplied to the stop switch 25 so that the motor driver 23 does not continue to drive the motor 12:

1. The position stop that occurs when the coordinate table 11 has reached the desired position,

2. the positive E *, counter switch and

3. the negative limit switch.

F i g. Figure 2C shows stop logic circuit 30, the four Has inputs: the input 30/4 from the stop-hold circuit 35, which indicates that the coordinate table 11 the has reached the desired location; a second input 30B, which indicates that the coordinate table 11 is in the has moved positive direction to the end of the web, and a third input 3OC for the negative end of the web. A fourth input 30/3 causes a with the stop logic Polarity reversal in order to move out of the end positions. The output of the stop logic 30 leads over the line 25/4 to stop switch 25.

The stop logic 30 thus acts as an interface between the various sources for stop signals and the stop switch 25, which keeps any signal away from the motor driver 23 and thus stops the motor 12. In Fig. 5 shows the switching network for the state of the slop switch 25 and thus of the motor 2 , which consists of the TTL modules G 1, G 2 and C 3. G i can be designed as a hexadecimal inverter that has 6 inputs and 6 outputs. It drives module G 2, which contains two double- input NAND gates, and in turn drives module G3, a four-input NAND gate. The outputs from module G I are always opposite to the inputs. The effect of the NAND logic G 2 and G3 is that there is only no output signal if all inputs carry a signal. A single or several signalfrcic inputs will therefore always generate an output signal.

The three ways in which the stop logic 30 denies

is stop switch 25 can affect, can be as follows to be discribed.

1. When the position is stopped, when the coordinate table 11 is in the target position or in its immediate vicinity, a high signal appears at the input 30/4 of the stop logic 30, which originates from the stop switch 35. The high goes to the inverter G 1-4, which causes a signal low at one of the inputs of the NAND circuit G3 , although G3 has three other inputs. the low at one input will cause a high at output 25/4 regardless of the signal status of the other inputs.

2. If the positive end stop, which occurs when the coordinate table 11 for whatever reason reaches the end of its path and actuates a limit switch located there and not shown in the drawing, causes the motor to stop. If the coordinate table 11 does not hit the limit switch, the input 30ß is high because a positive voltage is fed through the resistor R 1. If the positive end of the table track is reached, then a low signal is applied to the inverter G 1 B, whereby a high signal is applied to one of the inputs of G2A . Because the motor is necessarily rotating in a positive direction

imttt., Ot uci £ ~ ciuticiictiigaiig jvu ι itui.ii, wuuufk.u the second input of the NAND circuit G2A is excited. The output of this NAND circuit is therefore low, which in turn produces a high at output 25/4 of NAND circuit G3.

3. The negative end stop is effected when the coordinate table 11 has reached the negative end of its path and arranged therein, switches, not shown in the drawing operates This occurs at the input 3oC and thus at the input of G 1 B a logic low signal on, which produces a high at the input of NAND circuit G2S. Since the motor 12 previously necessarily turned in the negative direction, the sign signal at the input 30CL is a logic low, which at the inverter therefore GlCanliegt At the upper input of the NAND circuit G2B is a high, so the output of G2B by G3 is low, and thus a high output signal arises on line 25/4

It is now clear that each limit switch interrupts the movement as soon as the coordinate table 11 moves too far moved in its direction The limit switch only interrupts the movement in its direction and does not hinder backward movement. It is also clear that all three stop conditions have a high output of the

Generate NAND circuit C3 . This high output influences the stop switch 25 via line 25Λ, which stops the motor 12.

So that the digital / analog converter 27 is fed to an input 27 A in the form of a binary-coded decimal signal di »difference between the target position and the actual position of the work table or workpiece, a comparison device 31, hereinafter referred to as an error generator 31 designated, provided. The error generator 31 in FIG. 2B contains an input 31, 4 to which the BCD address of the desired position of the workpiece with respect to a reference signal is fed. The second input 31 B carries a BCD signal, which receives the actual position of the workpiece displayed at any time by an actual position value transmitter 40. The digital error generator 31 is known per se, but will be explained below with reference to FIGS. 6 to 9.

The digital error generator 31 is basically a BCD subtractor. To subtract two numbers from each other, the subtrahent is complemented to 9, that is, each digit is subtracted from 9 and then added to the minuend. If the sum results in a carry, this is added to the last significant digit of the sum. This process is also known as "carry back". The sum is then equal to the difference in the original subtraction. If the sum has no carry over, it is itself complemented to nine. This means that the difference is negative. The digital value of the coordinate table position, denoted by B in the drawing, for example 31 B, is derived from the value of the nominal position, denoted as A in the drawing, such as 31/4. referred to, deducted according to the nine's complement method. The difference is represented in the D / A converter 27 as an analog signal and fed to the motor driver 23.

The subtraction could of course also be done using the tens's complement method for every digit of 9 would be deducted and added to the result 1. This would add the carry over to Sum üucifiüaaig, ca would, however, be additional logic required to add the 1 to the complemented number when using the nine's complement method is not required. As with the nine's complement method the result would also be negative here, if no carryover occurs. A carryover occurs so it can be neglected. The Neuner ICompIement Method however, it is advantageous because the tens's complement method adds additional circuits requires, and should therefore be based on the F i g. 6 to 9 are described.

6 shows a block diagram of the error generator 31. The inputs A receive the address of the desired table position of the setpoint value. The inputs Ser contain the address of the actual position, the actual value. Each pair of inputs leads to a BCD adding circuit 32A to 32Λ /. Each adder circuit has an output on a nine's complement circuit 33Λ to 33ΛΓ. The difference, the output of the nine's complement circuits, is the binary-coded decimal number which corresponds to the difference between the target value and the actual value address, ie the error. For the sake of easier understanding, FIG. 6 denotes the digit with the lowest value with LSD (! East significant digit) and the digit with the highest value with MSD (most significant digit). Each BCD adding circuit 32Λ to 32N has a carry input (CI) and a carry output (CO); this one The carry output CO of the last stage 32 / V, which processes the digit with the highest value (MSD), is coupled to the inverter 34, its output to the inputs G of the nine complement circuits 33/4 through 33N goes.

In addition, the ¹ I carry, the highest digit, leads

'. Value also to the carry input Cl of the lowest value digit 32/4. In addition, the same signal is sent to its own output as a sign indicator. Each ß-input of an adder circuit is passed through its own nine-complement circuit 3151 to 3 IBN before it reaches the adder circuit as signal B ' . The 5 minuend signal is fed to input A and the subtrahend signal to input ßaus, the latter being complemented to nine and then added to the minuend. If there is no carry over, the sum A + B 'is complemented. If, on the other hand, a carry occurs, the sum is increased by 1, but not complemented. This operation is carried out in the nine-complement circuits 33/4 to 33 yV.

The nine-complement circuits contain an inverter 31C, an exclusive OR circuit 31D and a NOR circuit 31. The inverter 31C receives the lowest value digit of the digit group 2 ° to 2 ³ . The digit of the next higher value 2 'is, on the one hand, coupled directly to the output and, on the other hand, together with the digit of the value 2 ^2, to the exclusive-OR circuit 31D. The NOR circuit 31 £ has three inputs from positions 2 \ 2 ² and 2 ³ . These gate circuits are of a known type and generate output signals which can actuate further adder circuits. The following table provides a better understanding of the nine-complement circuits:

Decimal Complete BCD 2 ' 2 ' 2 " Complete 2- ' 2 ' 1 40 number number 0 0 0 2 ' 0 0 1 9 2 ' 0 0 1 1 0 0 0 0 8th 0 0 I. 0 1 1 I. 1 45 ' 7th 0 0 1 1 0 1 1 0 ^4J 2 6th 0 1 0 0 0 1 0 1 3 5 0 1 0 1 0 1 0 0 4th 4th 0 I. 1 0 0 0 1 1 5 3 0 1 I. 1 0 0 I. 0 50 6 2 0 0 0 0 0 0 0 1 50 ₇ 1 0 0 0 1 0 0 0 0 8th 0 1 0 9 1

2 ° is always inverted for complementation.
2 ¹ inverted as never before for complementation.

2 ² is only inverted when 2 ^{1 is} high.

2 ³ is inverted when 2 ¹ and 2 ^{2 are} low.

A nine-complement circuit 33A is shown in detail in FIG 33 C is set If the G input and the AND circuits are set to zero, the number at the input is complemented to nine.

In FIG. 8, the complemented positions are designated by C2 " and the non-complemented positions by C2". The exclusive-OR circuit 33 £> has essentially the same function as the AND circuits 335 and 33'Cünd an inverter, ° -bit to complement. The 2 'bit only needs one line because it is not inverted. The BGD adding circuits 32/4 to 32jV can, as shown in FIG. 9 shows, can be made from conventional components. Two known BGD adders ■ can be put together as shown in the drawing. The inputs to the first adder 36/4 are formed by the BCD decimal numbers of the nominal position and the actual position, the latter being complemented to nine. The AND circuits and the OR circuit are connected to the first adder in such a way that a correct carry occurs for the next following digit.

The position indicator supplies the error generator 31 with signals indicating the position of the coordinate table 11 during any time. It contains a position register for this purpose 41, Fig. 2B, which is a signal of the actual address of the coordinate table 11 in BCD coding to the Line 41Λ transmits. The line branches into 41/41 and 41/4 2. Branch 414 1 supplies the 5 input for the error generator 31, which with respect to FIG. 6 to 9 has been described. Branch 41/4 2 becomes only used if the control system is arranged accordingly. Various tax systems are still supposed to to be discribed. The position register 41 has a second output to an actual value display, which the indicates the actual address of the table so that the operator can operate the machine manually can intervene at any time. The position register 41 receives its signal from an electronic one Reading head 43, which interacts optically with the movable scale 44 and continuously shows the exact position of the Coordinate table 11 fixed with respect to a fixed reference point.

Numerically controlled position systems require an analog / digital conversion of the position values, since the digital form is more suitable for data processing and has a higher aiiflr.; siing provides al «hip analngp In addition, digital signals can be easily displayed and read by the operator.

Various digital position indicators can be used. A well-known indicator, the angular positions Translated into digital numbers, uses a rotating shaft with reading brushes, which are located on a ! move disk-shaped coded stator. For a more accurate reading, however, a position indicator is used preferred with optical diffraction gratings. When two ■ pitter in the required relationship to each other are arranged, interference patterns arise with the light wavelength and the optical constant the grid are related and are suitable for reading out the mutual position.

The error generator continuously generates a flow of information to the digital / analog converter 27 and thus to the motor 12. The information consists of a signal that consists of the difference between the actual position of the coordinate table 11 and the target position depends if this error signal is sufficiently small or is equal to zero, the stop switch 25 is to be actuated by the stop logic and thereby the flow of information to the Motor 12 interrupted and motor 12 stopped « will. In order to achieve this, the error signal from the error generator 31 also goes over the line 382? to the Stop generator 38. In its simplest form, the stop generator 38 is a comparator circuit that does the Compares the error signal with a predetermined value and, if it falls below the same value, a signal above Line 38/4 transmitted to the stop hold circuit, which in turn via lines 355 and 30/4 the Stop logic 30, which is shown in FIG. 5 is shown, controls and thus actuates the stop switch 25.

It will be understood that other methods of stopping the engine 12, such as the use of a Sign change in the error signal could be used to shut down the motor 12. Even could be obtained from the tacho amplifier 22/4 of the differential quotient of the tachometer signal, the becomes smaller, the closer the actual position approaches the target position, and its direction changes when this is exceeded in order to shut down the motor 12.

In order to hold the stop logic 30 in the required conditions, a stop switch 35 is provided provided, the stop logic 30 has a continuous one Provides a stop signal even if the triggering stop condition no longer lasts Stop switch 35 are fed a start signal via line 35Λ so that the motor 12 can start again can. These precautions are necessary because the engine 12 may stall should be, although the triggering stop condition no longer exists. For example, if the comparison signal is very small in the stop generator 38, the coordinate table 11 can still move through before the stop move the target position through it. Without the stop switch 35, the stop signal would then stop, and so would the motor 12 would drive the coordinate table 11 backwards again and thus cause the control to oscillate. that is just to be avoided. The stop switch 35 is designed so that it not only, as described, works automatically but can be activated manually by an operator at any time, if necessary

Fig. 10 shows the detailed circuit of the stop switch 35. A start signal at the input 35/4, which comes from the automatic / manual switch 50 and thus from the control unit 100, sets the flip-F.jp 35 £ Apr Hoc Start-S * O "- Si "r; 2! 355 ar.hsbt that is on the. Input 3OA of the stop logic 30 (see Fig. 10, 2B and 2C) is performed. The start signal 35Λ also resets the flip-flop 35F, the output 35D of which goes back to the NAND circuit 35G and the AND circuit 35 // which both control the flip-flop 35E. A reset output 35C, which is the inverse of the signal 35D, goes back to the automatic / manual switch 50 in order to display the state of the stop circuit 35 and thus of the motor 12.

As mentioned, the stop switch 25 is actuated via the stop logic 30 when the coordinate table 11 has reached the target position, but before the tool can start machining, it must be ensured that the coordinate table 11 has come to a complete standstill. Detector 45, which interacts directly with the X and Y tool control circuits 75 and 104 as well as the position register 41 The standstill detector 45 is shown in detail in Fig. 12. The input signal on line 45Λ from the position register carries the digits with the lowest value (LSD) to. The LSD input goes to two rows of inverters, the first row contains the inserters 46Λ and 465, the second row contains the inverters 47 / 4,475,47C and 47 £>. Between 46/4 and 465 the capacitor 46C is opposite ground, the capacitor is between inverters 475 and 47C in the second row

Il

47 E opposite earth. Both rows lead to the input 1 de, r AND circuit 48 and the NOR circuit 49. Both rows also lead via K.reu & to input 2 of the AND circuit and the NOR circuit. The outputs 48/4 and 49/4 lead to an OR circuit 50 ', the output 455 of which indicates that the coordinate table 11 has come to a complete stop. For the following explanation, the input signal from the line 45/1 is denoted by M, the output of the inverter 46 £> is denoted by N and that of the inverter 47 D is denoted by P. Both M and P go to the inputs of the AND and NOR circuits.

The circuit of FIG. 12 determines when the last bit of the position register has stopped changing for a certain time Δ. As can be seen, N • follows M when it goes from low to high. However, there is a delay Δ, due to capacitor 46Caui, as M goes high to low. Conversely, P follows M when M goes high to low, but has a delay A ₁ when M goes low to iHigh. As long as M changes its state faster than the time Δ, M cannot become equal to P. But if M changes slower than Δ, M equals P. Accordingly, the output on line 455 goes high as soon as the input holds one of its states for longer than Δ. By changing the capacitors 46C and 47 £, this time can be adjusted. If the lowest value digit in the position register 41 changes due to the damping of the drive, that is to say slowly enough, the standstill detector 45, that is, a standstill signal on line 455, is output.

The automatic / manual switch 50 mainly consists of a number of switches which are operated either by the operator or by the control unit 100 described below. A portion of the auto / manual shift 50 is shown in FIG. 11 shown in detail. It has a signal input 50A which originates either from the automatic part of the control unit 100 or from the manually operated control and actuates the NAND switch 51 for automatic operation or the NAND switch 32 for manual operation. The SchaUci 5tunü 52 can consist, for example, of a flip-flop or a relay, the output of which actuates a number of switches in order to pass information from the automatic input Ai to A 4 or from the manual input Mi to MA of the control. If the switches 51 and 52 are actuated by a high signal, a high signal on the line 50, 4 causes the switch S1 to be actuated, but a low signal, because of the inverter 54, causes the switch 52 to be actuated. Switch 51 «e holds the signals Ai, Λ2, A3, Λ4 on the NAND gates 53Λ, B, C and N, while the signals M 1, M2, M3 and M4 are switched off. A logic low at inverter 54, on the other hand, connects signals M 1 to M 4 with blocks 53 and switches off signals A 1 to A 4. The circuits 53Λ to 53iV thus receive either the input signals of the automatic control or those of the manual control.

In Fig. 11, the outputs of the NAND circuits 53Λ to N are denoted by the same numbers as the lines in F i g. 2 denote. The NAND circuit 53Λ is thus connected to the control amplifier 29 via the line 29A and, if necessary, regulates it to a low motor speed. The NAND circuit 532? supplies its output signal 54, which branches to lines 54 and 35Λ, to fine gate circuit 76 and for triggering stop switch 35. NAND circuit 53C resets position register 41 via line 55. The lines M 1 or A 1 go to a number of Von NAND circuits 53 / V, the outputs of which supply the setpoint position signals for the coordinate table 11 via the lines 31.

There are, of course, several ways in which the circuits of FIG. 11, for example, an input register can have a number of NAND circuits similar to the circuits 53Λ to N , which can receive input information such as the output 4551 of the standstill detector 45. The output of the position register 41 or the stop switch 35 is also attached for certain purposes. The output of the NAND circuits processing this information would then have to be divided up in a manner similar to that of switches 51 and 52, so that they would be distributed depending on the operating mode. Other outputs can, for example, operate the displays 57 of the target address and the display 58 of the actual address of the tool table.

When the stop switch 35 has shut down the motor 12 and the standstill detector 45 has given a corresponding display signal to the tool 10 via the line 4552, the tool 10 can be deflected to eliminate the remaining error between the target position and the actual position compensate for the workpiece in relation to the tool. The fine gate circuit 76, which enables the fine control and the tool control 75 of FIG. 1 belongs. The lowest value digits of the error signal are fed to the digital converter 80, which controls the tool driver 90, which initiates the movement of the tool 10. Fig. 13 shows the details of the arrangement. The fine gate circuit 76 contains two AND circuits 77 and 78 and a gate circuit 79. The AND circuit 77 receives the first control signal via line 54Λ from the output of the manual / automatic switch 50. The second input of the AND circuit comes via line 3551 from the stop switch 35, the signal is high, if the remaining position error within the Lagetoieranz the third input of the AND circuit comes via line 4552 om stop detector 45. the output 77A of the AND circuit reaches 77 as a first input to AND circuit 78th The second input of the AND circuit 78 comes from the fine adjustment circuit 97, which has the AND circuit 98 and the inverter 99. The input of the inverter 99 leads on line 99Λ

so signal when the target address 5 'is equal to the actual address A '. But if there is a difference between these addresses, then the output 995 of the inverter 99 is high, so that together with the high signal on line 77Λ 1, the AND circuit 78 is opened and a high signal on line 78Λ generates the AND -Circuits 79 opens. The output signal A 'of the error generator 31 arrives at the AND circuits 79 via the lines 31C. This signal is fed to the digital converter 80 via the line 81. Line 81 has four wires per digital digit, each with one bit for the values 2 ° to 2 ³ to lead. The place of the lowest value, which is labeled LSD, corresponds to the units value in the decimal system. The BCD signals are fed to the converter 82, the output of which goes in purely binary form to the multiplier 83, which determines the correct number of steps for the stepper motor by multiplication. The converter 82 is essentially an adder circuit. The multiplier

83 can be used as a 4-bit x 4-bit parallel binary multiplier be formed. The output of the multiplier 83 leads to driver 90, which is also shown in FIG. 13 is shown It contains a comparator 91 to which the output of the pulse counter 92 is also fed. A pulse generator 93 supplies the Irr pulse for counter 92 via line 93fi. The counter 92 adds or subtracts the received Pulses from the stored number, depending on whether the target address is larger or smaller than the actual address 5 'is as indicated at 91/4 and 91B The outputs of the comparator 91 v / earth is supplied to the motor driver 94, which as a stepper motor as the case may be trained drive element 5 drives forward or backward

The comparator 91 has a third output via line 91C which is connected to both the fine adjustment circuit 97, i.e. the inverter 99, as well as via branch 995 to automatic / manual switching. As already noted, the comparator delivers a high signal on this line if the target address is the same as the actual address

The control unit 100 Fig. 1 includes an automatic Control and a manual control for influencing the movement of the coordinate table 11 and the Tool 10. The automatic control can be by perforated tape, magnetic tape, punch cards or others Means take place, the signals of which the automatic / manual circuit 50 the necessary information in digital Feed remotely. The hand control can be a typewriter keyboard, a telephone dial or similar transmitter to pass on the information contain.

Of course, other control devices can also be used. For example, Fig. 15 shows a process control computer 120, which via its output lines 121 the desired address information to circuit 50. The circuit 50 in turn gives the actual address as well as various Status signals are returned to the process control computer 120 via lines 122 and 123. the Status signals relate, for example, to the control status of the amplifier 29, which is controlled by the line 29/4 is affected, the state of the fine gate circuit 76 and other parts of the system, such as polarity change conditions, the actuation of a limit switch, etc.

The process control computer 120 can be controlled by a τ data processing system 124. This the latter can have an output 125 to an interface unit 126 in order to be able to use the lines 127 to pass information on to the digital converter 80, for example. This allows editing through

be controlled in the tool after this precise machining position with respect to the workpiece Win was brought. An indication which causes this process can be provided by the fine adjustment circuit 97 are given. The described automatic

π control can be bridged by the manual control which is carried out via the manual input 128, which carries out the same operations via the lines 128Λ and 128ZJ can cause such as the computer 120. An input for manual input is via the keyboard 129, which The interface unit 126 is also influenced via the line 129/4 in order to control the tool.

The tool itself and the tool control can have different shapes. In the present example, the digital / analog converter 80, designated as BOA in FIG. 14, controls the tool. The tool consists of an electron beam 133, which is controlled via deflection plates 131 and 132 by the electrostatic deflection device 90/4 in such a way that it strikes the exact position of the workpiece W,

3n and carry out the desired processing there The type of execution can be compared with that of Fi g. 15 work together. The data processing system 124 initially ensures the precise setting of the electron beam in relation to the workpiece. This can then, for example, an integrated circuit in a corresponding Draw in the prepared silicon semiconductor chip. The fine adjustment circuit 974 of FIG. 14 can be the same as circuit 97 of FIG. she will effective if the difference between the target address and

w The actual address is zero or a sufficiently small value. The electrostatic deflector is an ordinary operational amplifier.

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Claims (4)

Patent claims: 1. Device for adjusting the relative position between tool and workpiece on processing machines with a first adjusting drive for coarse adjustment, which is in drive connection with a workpiece carrier, and with a second adjusting drive acting in two coordinates for fine adjustment, which is in Wtrk connection with the tool, wherein the positions of the workpiece carrier to be approached can be specified by a control unit, characterized in that the control unit (100) can output signals corresponding to the target position of the workpiece carrier (11) in relation to a machine-fixed reference point in two coordinates (X, Y) , which with the actual position of the workpiece carrier (11) in relation to the reference point 'corresponding signals of an actual position value transmitter (40) in a comparison device (31), whose output signals as error signals, the motors (12, 13) of the actuator for the workpiece carrier ( 11) control that when reaching preset limit values n for the error signals the workpiece carrier (11) can be stopped and the standstill of the workpiece carrier (11) can be detected by a standstill detector (45) and that when the standstill detector (45) responds, the drive elements (4, 5; 131, 132) of the tool actuating drive can be controlled by the plague error signals of the comparison device (31), whereby the tool (18Λ; 133) can be brought from a predetermined starting position into the exact position relative to the workpiece f H ^ in the sense of reducing the residual error signals until they are eliminated. 2. Apparatus according to claim 1, characterized in that each motor (12, 13) of the workpiece holder actuator a stop logic circuit (30) is assigned. with a stop switch (25) in There is an operative connection, the supply of the error signal to the occurrence of a stop condition Motor control circuit (21) interrupted. 3. Apparatus according to claim 1 or 2, characterized in that the standstill detector (45) with the actual position value encoder (40) is connected. the speed of the change in position is determined and if the position change is slow enough, a femtor switch (76) from coarse to fine adjustment switches. 4. Device according to one of claims I to 3 with one by electrical deflection devices position-adjustable electron beam as a tool, characterized in that the electrical deflection devices (9OA. 131, 132) when responding of the stillland detector (45) can be influenced by the residual error signals.