JPH03136725A - Method of setting process condition of electric discharge machining device - Google Patents

Abstract

PURPOSE:To set a process condition without increasing the capacity of memory by selecting a finishing process condition corresponding to a roughing process condition and selected from a finishing process condition table so as to reduce a roughing process condition table and the finishing table condition. CONSTITUTION:A roughing process condition table on which rows of process conditions corresponding only to roughing processes are registered, and a finishing process condition table on which rows of process conditions corresponding to finishing processes are registered, are provided, and a condition necessary for a certain process is previously set. A predetermined roughing condition is selected from the rows of process conditions registered on the roughing process condition table in accordance with the thus set condition. Then, a finishing process condition corresponding to the roughing process condition and selected from the finishing process condition table is selected so as to reduce the roughing and finishing process condition tables.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a machining condition setting method for an electrical discharge machining apparatus that can efficiently switch between a plurality of machining conditions and perform machining.

[Prior Art] Generally, electric discharge machining is performed while transitioning from machining with a large roughness of the machined surface, called rough machining, to machining with a small roughness of the machined surface, called finishing machining.

The machining conditions from rough machining to finishing machining, ie, conditions such as the electric discharge pulse current value and pulse time, are changed in stages. The purpose of switching this condition is that the machining speed is high under rough machining conditions, and by removing most of the machined part in rough machining and machining the remaining surface in finishing machining, the overall machining time can be shortened. . Since the discharge gap is large in rough machining, it is naturally necessary to bring the electrode close to the machined surface of the workpiece in finish machining.

That is, it is necessary to move the electrode in the processing feed direction and to move the electrode in a direction perpendicular to that direction, that is, to perform a swinging motion.

FIG. 3 shows an embodiment of an electrical discharge machining apparatus for explaining the conventional method. In the figure, [1] is the electrode, (2) is the workpiece, and (3) is the power supply. This power supply is connected to the electrode (1) and the workpiece (2), and sets the discharge pulse. It is something. (4) is a feed control device, which controls X, Y, Z
It controls each direction feeding device (5), (6), and (7). (8) is a processing device, and memory (9)
It reads the data and issues a discharge pulse to the electrode (3) and a sending command to the setting command sending control device (4).

The internal table structure of the memory (9) is as shown in Fig. 4, and the conditions of each discharge pulse, that is, the current value,
Conditions such as pulse time, machining allowance value when transitioning from that condition to the following conditions, gap value when machining is finished under those conditions, electrode (1) and workpiece (2) according to the machining conditions
) Parameters necessary for electrical discharge machining, such as separation motion (not shown), are stored as data. (lO) is a data setting section and is a condition for starting machining.

Various conditions necessary for machining, such as machining completion conditions, machining depth, and electrode reduction amount, which is the finished dimension difference between electrode (1) and workpiece (2), are set as data.

Here, the above-mentioned machining allowance value, gap value, and electrode reduction amount will be explained using FIG. The machining allowance value is the dimension obtained by subtracting the apparent electrode dimension during the oscillating movement of the electrode (1) from the final machining dimension, and is used when machining while changing the machining conditions until the final machining dimension is -1. There is also a view that it is the remaining machining allowance for finishing machining. The gap value refers to the discharge gap on both sides, and is used when finishing machining to desired machining dimensions under the machining conditions. The amount of electrode reduction is the final processed size minus the electrode size.

Next, the operation will be explained. In the condition table in Figure 4,
Set the condition number to start machining as 100, and set the condition number to end machining as 1.
02, the machining depth is 50 mm, the reduction amount of electrode (1) is 600 um, and the tip of electrode (1) and workpiece (2)
When the related coordinates are set to zero when the surfaces of ) and command the power supply (3) to set machining conditions such as current value SOA and pulse time 160 μs, and in the Z direction, Z direction movement amount = final machining depth - machining allowance value / 2 = SO
m m -5001t m / 2 = 49.75
m m Z = 49.75 mm Electrode processing feed up to the position of
-sooμm = 100gm The oscillating motion of the 1f pole (1) sends a 100μm movement command to the feed control device (4), and in the Z direction, the feed device (5) moves in the Z direction, and in the ZY force direction, respectively. The electrode (1) and the workpiece (2) are caused to swing in that direction by the feeding devices (6) and (7). When the movement is completed, data related to machining condition number 101 is read from the memory (9) and machining conditions are set, and in the same way as above, in the Z direction, Z direction movement amount = final machining depth - machining allowance. Value/2= SO
m m -400μm/2 = 49.80 mm Z = -49,80 mm Machining feed to the position of m,
In addition, the XY force direction is the amount of movement in the XY direction, the amount of electrode reduction, machining allowance value = 600 g
m - 400 μm = 200 μm Machining is performed by performing a swinging motion of 200 μm. Similarly, when the movement is completed, the data of end condition number 102 is read out first to set the machining conditions, and in the Z direction, the Z direction movement amount = final machining depth 1 gap value / 2 = SOmm -
150Bm12 = 49.925mm Z = -49,925mm Machining feed up to the position of m,
Further, in the XY force direction, the XY direction movement amount type electrode reduction amount gap value = 600 μm - 150 um = 450 μm, that is, the machining is completed by performing a swinging movement of 450 μm.

Now, when performing deep machining in low consumption machining using the electrode (1) made of copper or graphite, for example, it is necessary to use machining conditions with a large pulse width to shorten the machining time. Machining conditions with a large pulse width can cause granular protrusions on the tip of the electrode, known as pitting, to remain on the tip of the graphite electrode as shown in Figure 6 (a), causing unstable machining, preventing machining from proceeding or causing arcs. There are some drawbacks. The occurrence of pitting is proportional to the machining depth, and this tendency becomes more pronounced as finishing machining progresses.

Therefore, general machining conditions include a machine that will not fail no matter who is machining it, a machine that does not cause pitting even when deep machining is performed as shown in Fig. 6 (b), and a machine that has a large amount of wear.
A processing condition sequence with a small pulse width as shown in the figure was registered. On the other hand, the processing conditions for copper electrodes with large pulse widths are as follows:
Due to drawbacks such as unstable machining, reduced machining speed, and increased machining time, the machining conditions were somewhat consuming.

When performing from rough machining to finishing machining using such a machining condition sequence, as the finishing machining progresses, the electrode (1)
The wear and roughness of the electrode (i) was noticeable, and it was not possible to process a large number of parts using the - electrode (i) at several locations, and there were cases where several electrodes (1) were replaced during the machining at the - location.

In order to eliminate this drawback, as shown in Fig. 2, the starting machining conditions are set in advance to the machining conditions that require a lot of wear and tear, i.e., have a small pulse width, as in the past, and the following are set as machining conditions that require a slightly longer pulse time, are less consumable, and have less pitching. A method is used in which a large number of machining conditions that do not occur are created and registered.

[Problems to be Solved by the Invention] Since the machining condition setting method of the conventional electric discharge machining device is performed as described above, for example, as shown in FIG. For example, if you want to start machining from the machining condition number 102, you can change the data in the number 102 part or create another machining condition column according to the starting surface roughness, for example in Fig. 7 (c).
) As shown in (9), it is necessary to prepare a large number of
There were issues that needed to be resolved, such as an increase in capacity, time-consuming data input, and complicated operations that led to incorrect selection of processing conditions.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for setting machining conditions for an electric discharge machining apparatus that allows machining conditions to be set with simple operations without increasing memory capacity.

[Means for solving problems]

The method for setting machining conditions for an electric discharge machining device according to the present invention is a method for setting machining conditions corresponding to rough machining and finishing machining in the process of performing finishing machining following rough machining. a rough machining condition table in which a machining condition column is registered and a finishing machining condition table in which a machining condition column corresponding only to finishing machining is registered, and a step of presetting conditions necessary for machining; a step of selecting a predetermined machining condition from a machining condition column registered in the rough machining condition table based on the conditions specified in the rough machining condition; and a step of selecting a finishing machining condition corresponding to the rough machining condition from the finishing machining condition table. It is what it is.

[Effect]

This invention includes a rough machining condition table in which a machining condition column corresponding only to rough machining is registered, and a finishing machining condition table in which a machining condition column corresponding only to finishing machining is registered. Conditions are set in advance, and based on the set conditions, predetermined rough machining conditions are selected from the machining condition column registered in the rough machining condition table, and for finishing machining conditions, the selected rough machining conditions are selected from the finishing machining condition table. Select finishing machining conditions that correspond to rough machining conditions to reduce rough and finishing machining condition tables.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a flowchart for explaining one embodiment of the present invention, and the hardware configuration is the same as that shown in Figure 3. In Figure 3, (1) to (8) and (
IO) has the same configuration as the conventional one, so its explanation will be omitted. The internal table structure of the memory (9) includes a machining start condition column corresponding to the machining depth as shown in FIG. 2(a), and a row of machining start conditions as shown in FIG.
), and corresponding to numbers 100 to 106, the conditions of the discharge pulse, that is, the electrical machining conditions such as current value and pulse time, and the following from those conditions are as follows. machining allowance value when transitioning to finishing, gap value when machining is finished under those conditions, separation movement between electrode (1) and workpiece (2) depending on machining conditions (not shown), etc. Parameters necessary for electrical discharge machining are stored as data.

Comparing the machining condition column data for the actual machining start and finishing machining using the same numbers above, the machining start condition column indicates that pitching does not occur even if machining is performed to a predetermined machining depth, or machining becomes unstable. A condition with a shorter pulse time than the finish machining condition sequence is set so that the process does not occur. The surface roughness corresponds to the machining condition number, and the machining start condition has approximately the same value as the finishing machining condition, or a machining condition with a larger surface roughness than the next finishing machining condition is set. That is, S'N-1>SN≧S'N S'N-1: Surface roughness of finishing machining conditions of number N-1 SN = Surface roughness of machining start conditions of number N S'N: Finishing machining of number N It is set to be related to the surface roughness of the conditions. As a result, when machining is performed in numerical order, the surface roughness is always reduced and efficient machining is possible.

Next, the operation will be explained using FIGS. 1 to 3.

Among the conditions in Figure 2, the condition number Ns for starting machining is 100.
, the condition number N for finishing machining is set to 102.

Machining depth is 50mm, reduction amount of electrode (1) is 500μm
The machining operation will be explained as follows. When the processing condition data described above is input to the data setting unit (10) and executed (step 20), the processing device (8) described above starts processing.

The current machining condition number N is the machining start condition Ns number 100.
is substituted (step 21), and it is determined whether the starting machining condition is Ns (step 22). Here, for the start condition Ns, select (a) in Fig. 2 as the machining start condition string that uses the machining depth from the data (step 23), and read out data related to machining condition 100 from the memory (9). Step 25), parameters such as current value SOA and pulse time of 150 μs are set for the power source (3) (Step 26). Next, it is determined whether the current machining condition N is the end condition Ne or not (step 27), and since it is not the end condition Ne, the machining allowance value data C11 is set (step 28). A command is generated (step 29) and sent to the feed control device (4). -49,76 mm in the Z direction by the feeding device (5)
The position movement is carried out by the feed device (6) in the
, by (7), a swinging motion such as a circular motion of 120 μm is performed between the electrode (1) and the workpiece (2) (
Step 32). When the movement is completed, it is determined whether the current machining condition N is the end condition Ne or not (Step 33), the end condition M is determined.
Since it is not e, add 1 to the current machining condition N data (
Step 34) Return to step 22.

Similarly, determine whether the starting machining conditions are Ns (Step 22)
, here, since N = 101 and not the starting condition N3, FIG.
) and set parameters such as a current value of 30 A and a pulse time of 140 μs for the electrode (3) (step 26). Next, it is determined whether the machining end condition is Ne or not (Step 27), and since it is not the end condition Ne, the machining allowance value CHS- is selected (Step 28), and -4 in the Z direction.
Position movement to 9,79mm, XY force direction is 180μm
A swing movement command is generated (step 29) and sent to the feed control device (4), and in the Z direction, the Z
The relative movement in the X and Y directions is performed by a feed device (6
), (7) to cause relative movement between the electrode (1) and the workpiece (2) (step 32). When the movement is completed, it is determined whether the end condition is Ne or not (step 33). Since the end condition is not Ne, 1 is added to the data of the current machining condition N (step 34), and the process returns to step 22. Similarly, it is determined whether the starting machining condition is Ns or not (step 22), but since it is not the starting condition Ns, the finishing machining condition column shown in FIG. Read step 24), '[source (3)
Parameters such as a current value of 20 A and a pulse time of 120 μs are set for the current value (step 26). Next, it is determined whether the machining end condition is Ne or not (Step 27), and since the end condition is Ne, the machining allowance value data G is selected (Step 30).
As before, a position movement command of -49,92 mm is generated in the Z direction, and a swing movement command of 440 μm is generated in the XY force direction (
Step 31) The relative movement in the Z direction is controlled by the feed control device (4), and the relative movement in the Z direction is controlled by the feed device (5).
In the force direction, relative movement is performed between the electrode (1) and the workpiece (2) by the feed devices (6) and [7], respectively (step 32). When the movement is completed, it is determined whether the current machining condition N meets the termination condition Ne (step 33), and since the termination condition Ne is met, the series of machining operations is terminated.

As described above, the machining condition table shown in FIG. 7 showing the conventional example is thickened (reduced).

Here, only two tables are shown as starting machining condition columns, but as in step 25 in Fig. 2, it is possible to prepare multiple optimal low-consumption machining conditions according to the machining depth, and to use the machining conditions between them. By making the relationship between the number and the surface roughness almost the same, it is possible to carry out machining with optimum low consumption, and to obtain the same effects as in the previous embodiment.

Further, in the embodiment, the machining cost and gap value data in the start machining condition row and the finish machining condition row are described as being the same values as in the machining feed direction and the direction perpendicular to the machining feed direction, but the data may be set separately for each.

In this embodiment, the registration of data related to machining has been explained in a state where it is stored in the memory (9) in advance. A plurality of data may be prepared, read out and displayed as appropriate depending on the machining depth, and machining data may be stored from the data setting section.

【Effect of the invention〕

As described above, according to the present invention, a rough machining condition table in which a machining condition column corresponding only to rough machining is registered, and a finishing machining condition table in which a machining condition column corresponding only to finishing machining is registered. In preparation, the conditions necessary for machining are set in advance, and based on the set conditions, a predetermined rough machining condition is selected from the machining condition column registered in the rough machining condition table above, and for finishing machining conditions, the above finishing machining conditions are selected. Finishing conditions corresponding to the roughing conditions selected above are selected from the table to reduce the number of roughing and finishing condition tables, so machining conditions can be set with simple operations without increasing memory capacity. The effect is that you get what you can do.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of a machining condition setting method for an electric discharge machining apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart for explaining a machining condition table for an electric discharge machining apparatus according to an embodiment of the present invention. 3 is a block diagram showing the configuration of a conventional electrical discharge machining device, FIG. 4 is a diagram showing an example of a general machining condition table of a conventional electrical discharge machining device, and FIG. 5 is a block diagram showing the configuration of a conventional electrical discharge machining device. A diagram for explaining the definition of conditions. FIG. 6 is a diagram showing a pitting phenomenon occurring in a graphite electrode, and FIG. 7 is a diagram showing a large number of machining condition tables prepared corresponding to each machining condition in a conventional electrical discharge machining apparatus. In the figure, (20) is the step for setting machining conditions, (24) is the step of selecting predetermined machining conditions from the finishing machining conditions table, and (25) is the step of selecting predetermined machining conditions from the rough machining conditions table. This step is to In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In the process of performing finishing machining following rough machining, in the machining condition setting method of the electric discharge machining device that sets machining conditions corresponding to the rough machining and finishing machining described above, a machining condition column that corresponds only to rough machining is registered. A stage of presetting the conditions necessary for machining, and a stage of setting the conditions necessary for machining in advance, and performing the rough machining based on the set conditions. Electrical discharge machining comprising the steps of selecting predetermined machining conditions from a machining condition column registered in a condition table, and selecting finishing machining conditions corresponding to the rough machining conditions from the finishing machining condition table. How to set the processing conditions of the equipment.