JPS62246408A - Control method for deep hole drilling cycle - Google Patents

Abstract

PURPOSE:To eliminate a wasteful return operation and enable quick machining by making return control on the understanding that chips have accumulated, when the actual load value of a spindle has exceeded an initial load multiplied by a predetermined value. CONSTITUTION:A load detecting means 21 for a spindle Amp 20 detects an actual load working on a spindle 44 and outputs the load to an NC device 10. And the load comparator 14 of the NC device 10 reads out an initial load stored in a memory means 13 and compares an actual load with a value resulting from the initial load multiplied by a predetermined value. If the actual load has exceeded the initial load so multiplied, the comparator 14 detects the load on the understanding that chips from a drill 45 have accumulated, outputs a return signal 'OC' to a return operation control means 15 and makes a return operation for a Z-axis via a control means 11, a servo Amp 30 and a Z-axis feed motor 41, thereby eliminating a wasteful return operation and enabling quick machining.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a deep hole drill cycle control method in a numerically controlled machine tool, and in particular, a deep hole drill cycle in which the spindle load is detected and the return operation is performed. Regarding control method.

[Conventional technology]

To perform deep hole drilling with a numerically controlled machine tool, a method using G codes determined by JIS is used.

An example of this is shown in FIG. Figure 4 is JIS B6314
It is a figure which shows the processing example of the fixed cycle (Ga4) in. In the figure, 45 is a drill, the dotted line indicates rapid traverse of the drill, the solid line indicates movement by cutting feed, and q indicates the depth of cut per operation. As shown in the figure, the drill 45 performs positioning in the X and Y directions with rapid traverse, then descends in the Z-axis direction with rapid traverse above the hole drilling start point, performs a certain amount (q) of cutting, and once starts machining to remove chips. The machine moves up to the point, then descends in rapid traverse to the machining interruption point, and performs the next machining. Machining is completed by performing intermittent feeding many times in this way. Such a Canadian program conforms to International Standard 130 1056,
It is also specified in the American standard EIA R3-274 and is widely used.

FIG. 5 shows an example of a similar Canadian program. In the machining example shown in Figure 5, the drill does not return to the machining start point, and a certain amount (d)
This differs from the processing example shown in FIG. 4 in that only the curvature returns.

[Problem that the invention seeks to solve]

However, while such a system is widely used and useful, the programmer must always set the depth of cut with safety in mind. As a result, the drill has to perform lowering and raising operations more than necessary, and the machining time increases accordingly. Furthermore, the programmer must make the depth of cut (q) as thick as possible in order to shorten the machining time;
Determining the depth of cut requires a considerable amount of knowledge and experience, which places a burden on the programmer.The purpose of the present invention is to solve the above-mentioned problems and to eliminate the need for actually removing chips. To provide a deep hole drilling cycle control system configured to raise a drill only when the

[Means to solve the problem]

In order to solve the above problems, the present invention provides at least XY
A deep hole drill cycle control method comprising an axis control means for controlling a table and a Z-axis, and a spindle control means for controlling a spindle, comprising: a load detection means for detecting a load on the spindle during a drill cycle; initial load storage means for storing the initial load of the spindle detected by the detection means; load comparison means for comparing the stored initial load of the spindle multiplied by a constant value with the actual load of the spindle; When the load exceeds the initial load multiplied by a certain number, Z
A deep hole drill cycle control system is provided, comprising a return operation control means for controlling a shaft return process.

[Effect]

Since chips are removed smoothly near the machining start point, the initial load on the spindle is only the cutting load for actual machining.

On the other hand, the actual load is the machining load plus the load due to the accumulation of chips.

Therefore, when the initial load of the spindle and the actual load are compared, and the actual load value exceeds the value obtained by multiplying the initial load by a certain value, this indicates that chips have accumulated, so this is detected and the return control is performed. conduct. The reason for multiplying the initial load by a constant value is to eliminate the influence of load fluctuations and noise unrelated to chips.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention. In the figure, numeral 10 denotes a numerical control device (CNC), which includes axis control means 11, spindle control means 12, initial load storage means 13, load comparison means 14, and return operation control means 15. The axis control means 11 receives the axis command signals and outputs movement command signals for the XY table and the Z axis. The spindle control means 12 receives a spindle command signal inside the numerical control device IO and outputs a speed command signal for driving the spindle motor. The initial load storage means 13 stores the load (load current in this embodiment) in a state in which the first chips of hole drilling have been smoothly removed to the outside and only the cutting load for drilling is applied. The load comparison means 14 compares the initial load current of machining with the actual actual load current, and when the actual load current exceeds a value obtained by multiplying the initial load current value by a certain number, it sends a signal OC to the return operation control means 15. put out. The return operation control means 15 receives the signal OC from the load comparison means 14 and performs a Z-axis return operation.

20 is a spindle amplifier, and spindle control means 1
In response to a speed command signal from 2, a spindle motor 42, which will be described later, is driven. Further, a load comparison means 21 is built in, and the load comparison means 21 detects a load current of a spindle motor 42, which will be described later, and stores the initial load storage means 13 and the load comparison means 14.
Output to.

30 is a servo amplifier which drives the Z-axis feed motor 41 in response to commands from the axis control means 11. Machine XY
The X-axis feed motor that drives the table and the servo amplifier that drives the Y transport remoter are omitted.

Reference numeral 40 denotes a machine such as a machining center that performs drilling, including a Z-axis feed motor 41 that drives the Z-axis, a spindle motor 42 that drives the spindle, a Z-axis 43, a spindle 44, a drill 45 that performs drilling, and a It consists of a workpiece 46, an XY table 47 for XY positioning, and the like.

Next, the operation of this embodiment will be described based on a flow chart. FIG. 2 shows a flowchart of this embodiment. In the figure, steps are represented as Sl, S2, and S3.

In Sl, the drill first approaches the hole drilling start point in rapid traverse.

In S2, drilling is started. Rotation of the spindle 44 is actually started.

In S3, the drill is cut in, and the initial negative current is measured for a certain period of time, read, and stored in the initial load storage means 13.

In S4, it is determined whether the drill has reached the bottom of the hole. Y
If it is ES, the process advances to S9 and the drill returns to the drilling start point and the machining ends. If NO, proceed to the next step 85.

In S5, the actual load current (I3) and the initial load current (xr) multiplied by a constant number (α) are compared.

This constant number (α) generally has a value of about 1.1 to 1.2. Of course, this value varies depending on the material of the workpiece, processing conditions, etc. When the load current is smaller than this value (α·I,), the process returns to S4. The value of the load current is this value (α・If)
If it is larger, proceed to S6.

In S6, the load current (11) is larger than the value (α·If) obtained by multiplying the initial current (If) by a constant number (α), and the return operation control means 15 performs the return operation. The return operation can be a fixed amount or return to the starting point of hole machining, and can be switched by parameters etc. inside the numerical control device. When the return operation is completed, the process advances to 87.

In S7, the process rapidly returns to the machining interruption point, resumes drilling, and then returns to S4.

In this way, the value obtained by multiplying the initial current by a certain number is compared with the actual load current, and the return operation is performed only when the value of the actual load current exceeds this value, that is, when chips become clogged. There is no need for unnecessary return movements, and machining speed is increased.
Also, programming becomes easier.

Next, the hardware configuration of this embodiment will be described based on the drawings. FIG. 3 shows a block diagram of the hardware of the first embodiment. In the figure, ■ is the CPU that controls the whole
, 2 is a ROM that stores control programs, 3 is a RAM that stores various parameters and data, 4 is a CRT that displays data, 5 is a keyboard for inputting data, and 6 is an input unit such as a tape league. 7 is an interface for exchanging signals with the outside, and 51 is a machine operation panel for operating the machine.

Reference numeral 8 denotes an axis control circuit for controlling the axis, which includes an axis position control circuit and the like for each axis. A servo unit 30 drives the Z transport motor 41 in response to commands from the axis control circuit 8. Axis control circuits, servo amplifiers, and motors for the X and Y axes are omitted.

Reference numeral 9 denotes a spindle control circuit, which includes a DA converter and the like for converting a command value into a DA converter. Reference numeral 20 denotes a spindle amplifier, which drives the spindle motor 42 in response to commands from the spindle control circuit 9, has a built-in load comparison means 21, and detects the load current of the spindle motor 42.In the above embodiment, the load of the spindle is used as the load. Although current is used, the load can also be detected by other means, such as sound during machining, vibration, distortion of the main shaft, etc.

Furthermore, it is also possible to specify a larger depth of cut than in the past using a program, detect the load and perform a return operation within a certain range, and perform a return operation using the program when the cut exceeds a certain range.

〔Effect of the invention〕

As described above, in the present invention, the return operation is performed when the actual load on the spindle exceeds the value obtained by multiplying the initial load by a certain value, so there is no unnecessary return operation (machining is performed quickly, and the program It also becomes easier.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of an embodiment of the present invention, FIG. 2 is a flowchart diagram of the above embodiment, FIG. 3 is a block diagram of hardware of the above embodiment, and FIG. 4 is a block diagram of the hardware of the above embodiment. FIG. 5 is a diagram showing an example of fixed cycle (Ga4) machining according to JIS B6314 as a conventional example, and FIG. 5 is a diagram showing an example of deep hole machining cycle machining as a conventional example. 1-- CPU 2--ROM 3-- RAM 8--Axis control circuit 9--Spindle control circuit 10-- Numerical control device (CNC) 11...-1--Axis control means 12--Spindle control means 13...
--- Initial load storage means 14 --- Load comparison means 15 --- Return operation control means 20 --- Spindle amplifier 30 --- Servo amplifier 40 --- Machine 41 ·································································································································. Figure 3 Figure 4 Figure 5

Claims (5)

[Claims] (1) In a deep hole drill cycle control system comprising at least an axis control means for controlling an XY table and a Z axis, and a spindle control means for controlling a spindle, a load detection method for detecting the load on the spindle during a drill cycle means, initial load storage means for storing the initial load of the spindle detected by the load detection means, and load comparison means for comparing the stored initial load of the spindle multiplied by a constant value with the actual load of the spindle. A deep hole drill cycle control characterized by comprising: means for controlling a return operation to perform a return process of the Z axis when the actual load exceeds a value obtained by multiplying the initial load by a certain number. method. (2) The deep hole drilling cycle control method according to claim 1, characterized in that the initial load of the spindle and the actual load of the spindle are detected from the load current of a spindle motor. (3) The detection of the initial load on the spindle and the actual load on the spindle is configured to be detected as a digital signal by a servo unit.
Deep hole drilling cycle control method. (4) The deep hole drilling cycle control method according to claim 1, 2 or 3, wherein the return operation control means is configured to return the Z axis to the drilling start point. (5) The return operation control means is configured to return the Z-axis by a predetermined amount.
Deep hole drill cycle control method as described in Section 3 or Section 3.