WO1992015423A1

WO1992015423A1 - Method of controlling piercing of a laser machining apparatus

Info

Publication number: WO1992015423A1
Application number: PCT/JP1992/000242
Authority: WO
Inventors: Yoshinori Nakata; Norio Karube; Etsuo Yamazaki
Original assignee: Fanuc Ltd
Priority date: 1991-03-07
Filing date: 1992-02-28
Publication date: 1992-09-17
Also published as: JPH05185261A

Abstract

A method of controlling piercing of a laser machining apparatus to obtain good machining condition at the time of starting laser beam irradiation and reduce the piercing time. A peak value (S), a frequency (P) and a duty ratio (Q) which are the output parameters of a laser beam are maintained at minimum values (Ss, Ps, Qs) until a time (ta) lapses from the start of the laser beam irradiation. These parameters linearly increase during the period from the time (ta) to a time (tb) and are then maintained at maximum values (Se, Pe, Qe) during the period from the time (tb) to a time (tc). Thus, the laser beam output is maintained small at the start of irradiation (time 0 to ta) to prevent violent sputtering and to smoothly start the piercing. After the piercing has proceeded to some extent where sputting no more takes place (time ta and on), the output is continuously increased to perform the piercing smoothly and in short periods of time.

Description

Description Piercing control method of laser beam machine Technical field

The present invention relates to a piercing control method for a laser beam machine that performs piercing by pulse-controlling the output of a laser beam, and more particularly to a piercing control method for a laser beam machine that shortens the piercing time. Background technology

Generally, when laser processing metal or the like, piercing is performed at the beginning of the processing. Figure 5 shows the output waveform of the laser beam during this piercing. Normally, the output of the laser beam is determined by three parameters: peak value S, frequency P, and duty ratio Q of the laser pulse. As can be seen from FIGS. 5 (a), 5 (b), and 5 (c), in the conventional piercing, during the irradiation time t, each parameter has a constant value Sa, Pa and It is held in Q a. As a result, the overall output of the laser beam is also constant.

By the way, when irradiating the work with a laser beam, if the output is increased from the beginning, the spatter will scatter violently, causing a kind of thermal runaway state, and the molten metal will blow up to the work surface and piercing cannot be performed. . For this reason, conventionally, low-power piercing was used so that the machining condition at the start of piercing was good o However, conventional piercing had a problem that the piercing time was long because the output was low from the start to the end of laser beam irradiation. Disclosure of the invention

The present invention has been made in view of such a point, and provides a piercing control method for a laser processing machine capable of maintaining a good processing state at the start of laser beam irradiation and shortening the piercing time. The purpose is to do.

In order to solve the above problems, the present invention provides a piercing control method for a laser beam machine that performs piercing by pulse-controlling the output of a laser beam, wherein at least one of a peak value, a frequency, and a duty ratio of the laser beam pulse is used. One of the parameters is used as a parameter, and the time from the start of irradiation of the laser beam to the end of irradiation is divided into first, second, and third predetermined times in order from the start of irradiation, and the parameter value is divided into the first and second predetermined times. The first predetermined time continues at the minimum value, the second predetermined time continuously increases from the minimum value to the maximum value, and the third predetermined time continues at the maximum value. A piercing control method for a laser processing machine is provided.

By reducing the parameter value at the first predetermined time, which is the initial stage of irradiation start, piercing progresses while preheating the work so that thermal runaway does not occur, and piercing proceeds to some extent to prevent thermal runaway. By continuously increasing the value of the parameter at the second predetermined time at the point where the time has passed, and continuing the maximum value at the third predetermined time, the processing speed is accelerated, and the processing speed is smooth and short. The piercing takes place. Brief explanation of drawings

FIGS. 1 (a), 1 (b) and 1 (c) show the time-dependent changes of the laser beam parameter values in the present invention, and FIG. 1 (a) shows the peak value S 1 (b) shows the frequency P and Fig. 1 (c) shows the time change of the duty ratio Q.

FIG. 2 is a block diagram of an NC laser device to which the piercing control method for a laser beam machine according to the present invention is applied.

FIG. 3 is a diagram showing the output characteristics of the laser beam of the present invention,

FIG. 4 is a diagram showing a part of a parameter table of the present invention,

5 (a), 5 (b), and 5 (c) show the time-dependent changes in the parameter values of the conventional laser beam, and FIG. 5 (a) shows the peak value S, and FIG. (b) shows the frequency P, and Fig. 5 (c) shows the time change of the duty ratio Q. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of an NC laser device to which the piercing control method for a laser beam machine according to the present invention is applied. The processor 1 reads out the machining program stored in the memory 3 based on the control program stored in R0M2, and controls the operation of the entire NC laser device. The IZO unit 4 converts a control signal from the processor 1 and sends it to the laser oscillator 5. The laser oscillator 5 emits a pulsed laser beam 6 according to the converted control signal. This laser beam 6 is reflected by a bending mirror 7 and sent to a laser beam machine 8.

The laser machine 8 has a table 10 on which the workpiece 9 is fixed, A head 11 for irradiating the work 9 with a laser beam is provided. The laser beam 6 introduced into the head 11 is squeezed by the nozzle 11 a and irradiated on the work 9. The laser processing machine 8 has servomotors 12 and 13 for controlling the movement of the table 10 in two directions of the X-axis and the Y-axis, and a servo for controlling the movement of the head 11 up and down. A motor 14 is provided. These servo motors 12, 13, and 14 are connected to servo umbrellas 15, 16, and 17, respectively, and their rotation is controlled according to an axis control signal from the processor 1. The instruction to the laser beam machine 8 is given via the CRTZMD I device 18.

Next, a piercing control method in the NC laser device having the above configuration will be described.

In the present embodiment, the peak value S, frequency P, and duty ratio CI of the laser pulse are used as parameters for determining the output of the laser beam 6. FIGS. 1 (a), 1 (b) and 1 (c) show the time-dependent changes of these parameter values, where FIG. 1 (a) shows the peak value S and FIG. 1 (b) ) Is the frequency P, and Fig. 1 (c) is the time variation of the duty ratio Q. The peak value S is kept at a minimum 楦 S s from the start of the laser beam irradiation to the time ta. From the time ta to the time tb, a value expressed by the following equation (1) is taken.

Beak value S = (S e— S s) x (t-t a) / (t b-t a

) + S s (1) where S e is the maximum value and t is the elapsed time from the start of irradiation. From time tb to tc, it is kept at the maximum value Se.

Like the peak value S, the frequency P and the duty ratio Q From the start of laser beam irradiation to the time ta, the minimum value is maintained at P s and Q s, respectively.From the time ta to the time tb, the values expressed by the following equations (2) and (3) are obtained. take. Then, during the period from time tb to tc, the maximum values P e and Q e are maintained.

Frequency P = (P e— P s) x (t-t a) / (t b-t a)

+ Ps (2) Duty ratio Q = (Qe-Qs) X (t-ta) / (tb-ta) + Qs (3) Peak value S, frequency P and duty ratio Q of each parameter As described above, the output W of the laser beam 6 also has the same characteristics as the parameters in FIG. 1 as shown in FIG.

In this way, by reducing the output of the laser beam 6 at the beginning of the irradiation start (time 0 to ta), the piercing is started by injecting power into the work so as not to cause thermal runaway. When the piercing has progressed to a certain extent and thermal runaway has become difficult to occur (after time ta), the output is continuously increased at the upper limit at which thermal runaway does not occur, so that piercing can be performed smoothly and in a short time. Is performed.

By the way, the peak value S, frequency P, and duty ratio Q of each parameter need to be set to more appropriate values depending on various conditions such as the material of the work. In this embodiment, each parameter value can be set and stored in advance according to conditions. FIG. 4 is a diagram showing a part of a parameter table input and set by the CR TZMD I device 18. This parameter table consists of a data number column 40, an initial value column 41, and a final value 欐 42. The data number 欐 40 is a column for assigning a number for each data. In the initial value field 4 1 The minimum value S s, P s and Q s of the peak value S, frequency P and duty ratio Q, and time ta are input and set. In the final value column 42, the peak value S, the frequency P, and the maximum value Se, Pe of the duty ratio Q, and the times tb and tc are input and set.

The setting of this data can be program-input by the instruction code as follows.

G 1 0 L 1. 1 A 2 0 B 5 0 C 15 D 1 0 0 0;

(Four)

G 1 0 L 1.2 E 1 0 0 0 F 1 0 0 0 G 9 0 H 5 0 0 0

1 1 0 0 0 0; (5) Here, G 10 is an instruction code for performing a data input instruction. L is an instruction code for designating a data number and an initial value or a final value.L I.1 is in the column of initial value of data auditor 1 and L 1.2 is the same as the last of data auditor 1. This is an instruction code to input the data that follows the value 欐. A is the peak value S s, B is the frequency P s, C is the duty ratio Qs, D is the time ta, E is the peak value S e, F is the frequency P e, G is the duty ratio Qe, H Means time tb, and I means time tc. Therefore, the data input of Data Board 1 is completed only after the two commands (4) and (5) are input. Data entry for other data auditors is performed in the same manner.

In this way, if the parameter table in Fig. 4 is created before machining the work, a better number of data can be obtained by inputting the data numbers that match the conditions such as the material of the work in advance in the program. Lashing processing becomes possible. Piercing processing in this embodiment The command format is expressed as follows.

G 2 4 L 3;

Here, G24 is an instruction code for performing piercing processing, and L is a designation code for a data number.

In the above description, an example in which all parameters are changed as shown in FIG. 1 is shown. However, this is not always the case. For example, the peak value S is fixed, and the frequency P and the duty ratio Q are changed. It can be changed. That is, the peak value S, the frequency P, and the duty ratio Q can be changed in any combination depending on the material, the plate thickness, and the like.

As described above, in the present invention, by reducing the value of the parameter overnight at the first predetermined time which is the initial stage of the irradiation start, the processing proceeds while preheating the workpiece so as not to cause thermal runaway, When the piercing has progressed to a certain extent and thermal runaway has become difficult to occur, the value of the parameter is continuously increased in the second predetermined time, and the maximum value is maintained in the third predetermined time. Is accelerated, and piercing is performed smoothly and in a short time.

Claims

The scope of the claims

1. A piercing control method for a laser beam machine that performs piercing by pulse-controlling the output of a laser beam.

At least one of the peak value, frequency and duty ratio of the laser beam pulse is used as a parameter,

The time from the start of irradiation of the laser beam to the end of irradiation is divided into first, second and third predetermined times in order from the start of irradiation,

The parameter value continues at the minimum value for the first predetermined time, and the dog value increases continuously from the minimum value to the maximum value for the second predetermined time;

The piercing control method for a laser beam machine, wherein the third predetermined time continues at the maximum value.

2. The piercing control method for a laser beam machine according to claim 1, wherein the first, second, and third predetermined times can be arbitrarily set.

3. It has a plurality of data of a combination of the parameter value and the first, second and third predetermined times, each of which is given a test sign, and an operator at the time of the piercing. 2. The piercing control method for a laser beam machine according to claim 1, wherein data of the designated examination is automatically set.

4. The piercing control method for a laser beam machine according to claim 3, wherein the data is input as a program with a command code for commanding a piercing process and a command code for executing a data input command.

5. The data used at the time of piercing is stored in the program in advance. The piercing control method according to claim 3 or 4, wherein a code of the data is designated.