JPS62193728A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To enable the uniform and high accurate finishing to be performed, by measuring a time, required for machining in the preceding stage before machining in the final stage, and calculating, on the basis of this measured time, a necessary time for the machining in the final stage so as to perform the machining in the final stage, when multi machining is performed. CONSTITUTION:When multi n-stage machining is performed, a machine, when a machining condition switching unit 14 is switched to an n-1 stage by an output from a position detector 12, connects a switch 17 with an n-1 terminal to apply voltage of a power source 18 to a machining time measuring device 19, and if the machining reaches a desired depth, the machine, which outputs a signal from the detector 12 to the switching unit 14 to connect the switch 17 with an (n) terminal, finishes measuring a machining time. And the machine, in which a machining time in the final stage (n) calculated by an experimental result formula in an arithmetic unit 20 is fed to a machining time setter 21, starts a timer 22. And the machine, which actuates a switch 23 to set a machining condition in the n-th stage while actuates a machining finish decision device 24 and servo unit 10 if time elapses, finishes the machining.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electric discharge machining equipment @ζζ, and particularly to automatic setting Cζ of the machining time of the final stage machining in multi-stage machining.

[Conventional technology]

Conventionally, one example of this Kaede device was the one shown in Figure 2. In Fig. 2 6ζ, electric m(1) and Loe object(2)'
! = Machining the workpiece (2) by facing each other in the machining liquid (4) in the machining tank (3) and applying pulse current supplied from the pulse current supply device (5) to the machining gap. do. The electrode (1) is connected to the sliver (6) and the pole screw (7).
) is connected to the servo motor (8), and the (g1 rolling motion of the thermo-tp (81) is converted into the vertical motion of the electrode (1).

At this time, the overlap between the electrode (1) and the workpiece (2) is measured by the voltage measuring device (9), and depending on the magnitude of the voltage, the servo motor (8) from the servo device (α0)
), a signal is output to the electrode (1) and the workpiece (2
) The position of the pole (1) is read from the linear encoder 0 and input to the position detection device *aS. The position detection device @ compares in advance the desired value of the electrode feed depth for each cutting edge condition set in the machining position storage device (13) with the T position read from the linear encoder α pull, When the electrode (1) reaches the desired depth, a signal is output to the processing condition switching device α.
Reference numeral 41 denotes a machining condition setting device α9 composed of a resistor and the like in the machining current supply device (5), which is taken from a switch and a rich αQ that sequentially change the machining conditions set in the machining order. The sui-rich OQ has a t1 position detection device (2) in which the electrode (1) is set for each processing condition and reaches the desired depth.
) The signal C output from 1.

In normal electrical discharge machining, if the special number ζ, which is used to finish the surface to a desired surface roughness, is machined under the same finishing conditions from the beginning, it will take a very long time to process it because the electric energy is small.

First, the electrical energy is large and the machined surface i.
Most of the part to be machined is removed under rough machining conditions with roughness and high machining speed. Next, it is common to gradually reduce the energy Cζ and deepen the machining depth little by little, thereby making the surface i) finer. Take a look at this situation
As shown in the figure. In the same figure (a), the first stage (:(j) of machining is shown where the desired machining depth dj is cut, and the electrode feed depth d is machining under the first condition.
Rough machining is performed with large electrical energy up to 1. After that, as shown in the same figure (b), Cζ second. The processing is sequentially switched to the eighth processing condition, and processing is performed up to the electrode feed depths dz and dj, respectively. In this way, the electrical energy is gradually reduced, and the switch is made to the final nth condition as shown in (0) in the same figure, and the electrode (1) is cut to dn, which is the specific clearance gn under this condition from the desired machining depth d. If you send the desired surface roughness,
It can be finished to the desired depth. At this time, the number of processing steps n
It has been confirmed that the machining time is reduced as the number increases, but it is usually only a few steps due to the complexity of changing machining conditions.

In this example, n stages of machining conditions are set in advance in the machining condition setting device α9, and the electrode feed depth for each condition is set in the position memory device! (6), and when the electrode (1) reaches a desired depth under a certain machining condition, it switches to the next machining condition and performs the operation of machining to the desired depth under that condition for n stages. 4) When reaches the desired depth, the position detection device! (2) acts on the servo device Q (I and operates to raise the main shaft,
Processing is finished.

[Problem to be solved by the invention 3 In the case of the above-mentioned machining, each condition step is
・The machining time for each process increases, and the final n-th process usually takes the longest time. However, the smaller the surface roughness of the finishing process, the more remarkable this tendency becomes. In the case of electrical discharge machining, this means switching the machining conditions
When this occurs, the new condition has less energy than the previous condition, and the electrode (1) must be lowered to continue machining at the moment when no discharge occurs.6. However, the electrode (
1) Even if the metal is lowered to a certain level, the state of no discharge continues, and if it is lowered further, the discharge will start, but when the discharge starts, machining powder will be generated, which will fill the space between the machining holes. The apparent machining gap due to machining powder becomes narrower, causing so-called secondary radiation 1rk. There is a property that the amount of processing increases in the T part.

Therefore, in finishing machining, etc., when a small amount of cutting is required, if the amount of feed is small, the process will end without any discharge, and if the amount of feed is slightly large, the amount of machining will increase dramatically. In addition to the above, in the final machining, during the long machining time, thermal displacement occurs due to temperature changes, the electrode position drops, and the feed amount increases to more than the set value. If the electrode position rises and the feed amount decreases below the set value, the machining time becomes longer than necessary, and the machined surface may not be finished. In recent electrical discharge machining, there is an increasing number of molds that use the electrical discharge machined surface as it is without polishing the workpiece after electrical discharge machining, and in particular, variations in surface roughness are a problem that is consistent with machining time. In order to solve this problem, only the final n-stage knife machining machine should be machined to finish the surface roughness by machining only for a certain machining time without controlling the machining depth. I have been thinking about this. In this machining, only the surface roughness can be made finer without changing the machining shape or the machining depth, and the above-mentioned problem can be solved at the same time.

However, in reality, determining the machining time for final machining requires great skill and is difficult. This is because this is the size of the electrode.

This is because the machining depth and electrode shape vary greatly.

First of all, if you make a mistake in the settings, you may end up setting the time longer than necessary, causing stiffness and ending the process without finishing the roughness.

This invention has been made to solve the above problems, and provides an electrical discharge machining device that can automatically determine the machining time required for final machining for each machining based on the IyfI of the previous machining. The purpose is to

[First Means for Solving the Problems] The electric discharge machining apparatus according to the present invention Cζ includes a position detection device for detecting when the position of the electrode at each stage reaches a desired depth during multi-stage machining, and a A machining condition switching device that switches to the next stage machining condition based on the output, a machining time measuring device that measures the T-column machining time required for 10,000 loes, and a machining process that calculates the machining time measured by this machining time measuring device. It is a one-piece machine that includes a time calculation device, a machining time setting device that sets the numerical value calculated by the machining time calculation device as the machining time, and a timer that operates only for the time set by the machining time setting device. .

Ru.

[Effect]

In this invention, the machining time measuring device measures the time rIII required for the machining stage before the final stage machining, and based on the result, the machining time calculation device determines the machining time required for the final stage machining. The final stage machining is performed for the time determined by the time setting device and the timer, as well as by the arithmetic device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, the same reference numerals as in FIG. 2 indicate the same parts. During electric discharge machining Cζ tread n-stage machining, the output of the position detection bag @@ acts on the switch Qf9 in the machining condition switching device αa, and the blade conditions are switched in order, but this switch αQ
is also moving in sui-richaη, and is sequentially switched. However, the terminals of this switch α are not connected to any other terminals other than n-1 and n, and the terminals of the first to n-2
It doesn't do anything up to the stage.

When the machining conditions switch to the n-1st stage, there is a switch...
- The terminal is connected to the n-1 terminal, and the voltage of the DC power supply (to) is applied to the processing time measurement bag flIQI. This machining time measuring device (11) measures time only while the voltage of the DC Wll source (to) is being applied, that is, while machining is being performed under the (n-1)th condition, and the measurement result is is the time Tn-1 required for the n-1th stage machining.

The machining ζζ side electrode (1) of the n-1th stage is set to the desired depth dn-
1, the processing condition switching device α pull signal is output from the position detection device (12) as before, and the final nth
Switch to machining conditions. At the same time, Sui Richi αη
The terminal n-1 is also switched to terminal n, and the operation of the machining time measuring device α is completed. Measured y, = machining time T
n is given to the machining time calculation device and processed, and calculation formula C will be described here.

As mentioned above, in n-stage machining, the n-1st stage requires T
From this machining time Tn-1, the machining time Tn required for the final n-th stage machining is calculated, but from the experimental results, this machining time Tn is equal to the machining time Tn-1 of the n-1th stage.
It is known that a constant multiple of is sufficient. This constant varies somewhat depending on the surface roughness finish, but when processing a steel workpiece with a copper electrode, a value of about 0.5 to 2 is optimal.

In other words, the machining time for the final nth stage is Tn = TL-T
It is expressed by the formula n-1 ([=0.5 to 2).

When this calculation is completed, the calculation result Tn is given to the machining time setting device m (c), and the machining time for the nth machining is set. The timer operates only for the time set by the machining time setting device Q1), and after switch αη is switched to terminal n, the machining time is calculated and set. The operation will start later.

The above-mentioned timer @ works only during operation, and closes the timer. In other words, only when the timer (a) is running, the Sochi wire is closed, and ff1
It will be processed under n processing conditions. And the timer (
When the operation a) is completed, the machining completion determination device (c) determines that the timer operation has ended, and the servo circuit αQ
The machine moves to raise the spindle, and the machining ends. This completes the series of operations.

That is, in this invention, when performing n-stage machining, the machining time required for the n-1th stage machining is measured, and based on this, the machining time required for the n-th stage machining is calculated and the time is calculated. In this case, only the n-th stage of processing is performed.

Incidentally, in the above embodiment, machining C only in the vertical direction will be explained, but it can also be used for T-column electric discharge machining using oscillating machining.

Also, in the above example, the constant K in the calculation formula for machining time is 0.5 to 2, and as the material of the machining electrode and workpiece changes, this constant also changes. Needless to say.

〔Effect of the invention〕

As described above, according to the present invention, when performing multi-stage machining, the time required for machining one stage before the final machining is measured, the machining time required for the final machining is calculated based on this, and the machining time required for the final machining is calculated. The configuration is configured so that the final machining is performed only for the specified time.This makes it difficult to set the machining time for the final machining or automatically (
This electric discharge machining device can perform uniform and highly accurate machining because it does not require any skill and does not require redoing the machining time even if the size, shape, or machining depth of the electrode changes. There is an effect that can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electric discharge machining apparatus according to an embodiment of the present invention, No. 2N is a block diagram of a conventional electric discharge machining apparatus, and FIG. 8 is an explanatory diagram of multi-stage machining. In figure Cζ, (1) is an electrode,
(2) is the workpiece, (4) is the machining fluid, @ is the position detection device, α pull, 1t7JO working condition switching device, ao is the machining time measuring device, ■ is the machining time calculation device, 21J is the machining time setting device , (a) is a timer. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In electrical discharge machining equipment that performs machining by applying a pulse voltage between an electrode and a workpiece that face each other via machining fluid, a position detection device that detects the electrode position at each stage when performing multi-stage machining, and a position detection device that detects this position. There is a machining condition switching device that switches to the next stage machining conditions based on the output from the detection device, a machining time measuring device that measures the time required for the pre-stage machining of the final stage machining, and a machining time measuring device that changes the machining conditions of the next stage based on the output from the machining time measuring device. A machining time calculation device that calculates machining time, a machining time setting device that sets the calculation result of this machining time calculation device as the final stage machining time, and a timer that operates only for the machining time set by this machining time setting device. An electrical discharge machining device characterized by comprising: