JPS6317568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to optimal control of machining parameters of an electro-machining device.

The electric machining device supplies machining liquid to the machining gap between the electrode and the workpiece, applies a machining pulse, and performs pulse discharge to perform machining. Generally, the apparatus is capable of adjusting machining parameters, and the control device can be operated to adjust the machining gap, control the machining pulse, control the machining fluid, clean the machining gap, etc. This adjustment control should detect the discharge state of the machining gap and adjust it based on this, but the machining gap is constantly changing, and it is extremely difficult to adjust it to the best condition accordingly. This is clear from long experience.

The present invention has been made to solve this problem, and provides an apparatus that can always perform pre-programmed machining in the shortest possible time.

The present invention is characterized in that it is equipped with a memory that can store control information in advance and is provided with a microprocessor for arithmetic processing, thereby directly controlling machining parameters.

The following description will be given with reference to one embodiment of the drawings. FIG. 1 is a block diagram of a control device, in which the CPU is a central processing unit and includes a storage device M such as ROM and RAM. Command words and data control information are stored in M. Command words related to control of machining parameters such as machining gap, machining pulse, machining fluid supply, etc. are stored sequentially for consecutive addresses. For example, as shown in Fig. 2, the command words C11, C21,
C31... are stored one by one, and then the command words are similarly stored as C21, C22, C23....
At the time of reading, the data are read in the order of the addresses. Of course, the instruction words may be read out in any order. Further, data as shown in FIG. 3 is stored in M.

Next, in order to execute an instruction, the program counter is set to an address, and each time the counter increases by one, the CPU senses this and performs a read operation.
When the execution of one instruction is completed, the contents of the program counter are incremented by one, and then the contents of the address are taken out as an instruction word and the corresponding arithmetic processing is executed. Control of machining gap will now be explained. The structure of the stored data in M is shown in FIG. For example, as shown in the figure, B ₁ = 2, B ₂ = 10, B ₃ = 20,
B ₄ = 50, B ₅ = 100, B ₆ = 200, B ₇ = 500, B ₈ =
1000 pieces of data are encoded and stored. Data is read in 8 bits in parallel and transferred to the arithmetic registers on 8 lines on the data bus. Required data from these data are selected through arithmetic processing.

The detection data detected by the monitoring device is, for example, a signal detected by comparing the discharge state of the machining gap such as voltage, current, or impedance with a reference value, and the signal is shaped by a waveform shaping circuit and converted into a numerical value through an interface. It is input as information and stored in the accumulator. Operations are performed on the contents of this accumulator and the contents of the register. The calculation output is output through the interface, and PIA ₁ is used to raise and lower the machining gap control.
Command DOWN, and PIA ₂ issues a drive command.

FIG. 4 is a flowchart of the machining gap control, in which the process progresses between each block according to the arrows, and the required processing is performed in each block. Start with block 1, flag bit in block 2
Clears FLG and receives commands during machining in the machining gap. Next, proceed from block 2 and the arrow will
This leads to block 3 which asks whether FLG=O or not. If machining is being performed in the machining gap, a negative N is output; otherwise, a positive Y is output. If N, proceed to block 4 according to the arrow, and transfer detection data (DATA) from a monitoring device (not shown) that detects the discharge state of the machining gap to accumulator A.
, and reach block 5.

Block 5 checks whether the detected data stored in the accumulator A is equal to the stored data _B1 .
Ask whether A=B ₁ , that is, B ₁ is the minimum value of the stored data transferred from the memory M as explained in FIG. 3, B ₁ = 2, and other stored data are stage Therefore, B ₂ = 10, B ₃ = 20, B ₄ = 50, B ₅
= 100, B ₆ = 200, B ₇ = 500, and B ₈ = 1000. Then, if the comparison is made and A=B ₁ , the process proceeds from output Y to block 6 and data B ₁ =
2, and also when B ₁ < A < B ₂ , B ₁ =
Memorize 2. If the comparison result is a negative output N, other data is selected in block 7, and B ₂
If A<B ₃ , store B ₂ =10. Further, if the comparison result is N, the next data is selected, and after performing selection processing of the stored data according to the detected data, the arrow reaches block 8, which asks about the polarity of the detected data input into the accumulator A. If A<O, output Y reaches block 10 and PIA ₁ becomes “1”.
is output and the drive direction is UP, that is, a signal in the direction of widening the gap is output. Also, when A>O, N reaches block 9 and outputs "O" to PIA ₁ to indicate the driving direction.
DOWN and command to narrow the gap. Further, the path reaches block 11 and inquires whether the detected data stored in register B is O or not, B=O, and if it is negative, it reaches block 12 and generates one signal at PIA ₂ . The output is block 13 and register B is subtracted B-
1 → B, loop A ₁ is reversed and block 11
In the case of negative N, block 12 outputs one next signal pulse to PIA ₂ .

PIA ₂ signal pulse loops until B=O
The process continues by repeating _A1 , and when B=O, the loop _A1 stops, and the loop _A2 is reversed to stop the arithmetic processing. The number of pulses of the signal generated in PIA ₂ by this calculation process is the number of pulses corresponding to B ₁ = 2 or B ₂ = 10 of the memory data selected according to the detected data in blocks 6 and 7, and other values. That is, the stored data is selected in response to the input, and a signal having a manipulated variable (weight) corresponding to the selected value is generated by arithmetic processing.
In response to this command signal, the gap control drive control device sends a pulsed or analog control signal to the pulse motor,
In addition to controlling DC motors and hydraulic cylinders, the machining gap can be quickly and optimally controlled. Of course, the selection calculation process of the stored data is further weighted,
Furthermore, it can be arbitrarily decided to carry out the process in multiple stages. The Y output of block 11 goes back up loop A ₂ and goes to block 3.
is reached, and the detection data is again taken from the monitoring device. In this way, the information is collected while constantly monitoring changes in the state of the machining gap, weighted processing is performed by the microprocessor, and this output signal drives the control device to control the machining gap. Control is performed with increased responsiveness, ensuring optimal and stable control at all times. In addition, the above explained the servo control of the machining gap.Reciprocating control is generally performed in which when machining debris accumulates in the machining gap, the gap is widened and cleaning is performed using a pump action. This reciprocating control can be performed in combination with the servo control while monitoring.

Furthermore, the machining parameters such as the machining pulse and machining fluid supply described above can be controlled in the same manner.

Machining pulses are generally generated by turning on and off a power supply connected to the machining gap using a switch. For example, as shown in Fig. 5, the generated pulses are controlled by interrupting a pulse train having a short machining unit pulse width τon and interval τoff by a pulse-free interval τp off, so that a pulse train with a duration time width τp on and an interruption interval are controlled. τp
Generates a pulse train that repeats off and performs machining in addition to the machining gap.

Such a pulse train is generated by controlling the switch using a gate pulse, but it is necessary to control the gate circuit according to the discharge state. That is, τp on
to control the machining speed and change the machining conditions from rough machining to finishing machining. In addition, τp off eliminates arcs and short circuits by interrupting the discharge, and generated machining debris is removed during this interruption to clean the gap, so it is necessary to sequentially control these according to the condition of the gap. , and sometimes it is also necessary to control Ip, τon, τoff, etc. It is also necessary to change and control these processing materials, processing shapes, etc. τp on is repeatedly increased within a predetermined range within which normal machining is obtained, and if an abnormality is observed, it is gradually decreased, and a correction program is provided so that it always approaches the maximum value for the target machining. , τp
off performs the opposite operation to the above and determines the best value.
In this program control, instead of advancing or retracting the interval one by one, by analyzing the input information, it is possible to carry out weighted control such that the interval advances or retracts in two or three jumps in some cases. Allows for better control.

All such control information is stored in the memory M, and the CPU sequentially retrieves it, analyzes and processes the contents based on the detection data input from the monitoring device, and adjusts the amount of operation to bring it closer to the optimal state. The gate circuit is controlled by sequentially sending out signals having the following values. Of course, parameter control is not limited to independent control of the gate circuit; for example, cleaning control is performed in which machining debris accumulated in the gap due to pulse train discharge is removed during that period by interruption control, but even with this cleaning, If it is not sufficient, it is necessary to widen the gap using reciprocating control for cleaning, and it is also effective to increase the pressure of the machining fluid jetted during cleaning.This combination of machining parameters can be controlled by the CPU. The calculation process can be performed optimally.

As described above, the present invention stores control information regarding at least one of machining gap servo control, reciprocating control, machining pulse parameter control, or machining fluid supply control in a storage device, and Therefore, the data stored in the storage device is selected in response to the detected data from the monitoring device, and arithmetic processing is performed to generate a signal having an operation amount corresponding to the selected value, and the signal generated by this calculation device is used. Servo control of the machining gap, reciprocating control,
Since at least one of machining pulse parameter control or machining fluid supply control is controlled, optimal control with increased responsiveness can be performed, and control can always be performed in the best condition to meet the objectives. Machining can be performed accurately and in the shortest possible time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention; FIG. 2 is an explanatory diagram illustrating the address arrangement and instruction words in the memory; FIG. 3 is an explanatory diagram of the structure of data stored in the memory; The figure is a flowchart of one embodiment of the CPU, and FIG. 5 is an explanatory diagram of one embodiment of the processing pulse waveform.

Claims (1)

[Claims] 1. In an electric machining device that supplies a machining liquid to a machining gap between an electrode and a workpiece and applies a machining pulse to perform machining by pulsed discharge, a monitoring device that detects the state of the pulsed discharge; a storage device that stores control information regarding at least one of servo control, reciprocating control, machining pulse parameter control, or machining fluid supply control;
an arithmetic processing device that selects data stored in the storage device in response to detected data from the monitoring device and executes arithmetic processing to generate a signal having an operation amount corresponding to the selected value; and a control device that controls at least one of servo control of the machining gap, reciprocating control, parameter control of machining pulses, or control of machining fluid supply based on the generated signal. Processing equipment.