JPS60127910A - Control method of cutting in drilling machine - Google Patents

Abstract

PURPOSE:To reduce vibration and noise in drilling and improve its surface roughness, by controlling a driving power source for feeding a drill in accordance with an arithmetic compared result of the present feed speed of the drill with its programmed feed speed when the drill is moved to be fed. CONSTITUTION:When a drilling machine performs its drilling work by turning a motor 7 through a feed thread 6 to feed downward a head 3 mounting a drill 1, a present feed speed of the drill 1 is detected in a present speed detecting part 12 by a pulse signal from a feed speed pulse detector 11. An arithmetic part 16, arithmetically comparing this present feed speed with the programmed mode of feed speed from the programmed feed speed memory unit 15, outputs a deviation signal to a correcting part 17. Then a correction signal obtained here is given to a control part 18, correcting a motor control signal due to a setter part 14, in this way, controlling the motor 7 so that the drill 1 may be moved by the programmed mode of feed speed in the selected feed speed for the drill 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting control method in a drilling machine.

Generally, various types of hole machining such as drilling with a drilling machine are performed by sending a rotating drill into the rigid material, but this affects the surface roughness of the drilled hole etc. Cutting motion and feeding motion are deeply involved in vibration and noise caused by this vibration.

In other words, conventionally, to improve surface roughness and reduce vibration and noise, it was thought that the rotational speed, thrust force, or feed rate of the drill should be optimized by taking into account the material of the workpiece and the material of the cutting edge of the drill. This is because the processing is performed under conditions that allow

However, even with conventional countermeasures, vibration problems still exist.
In particular, the current situation is that the problem of vibration during heavy cutting has not been resolved.

In view of the current state of hole drilling using a drill, the present invention reduces vibration and noise and improves surface roughness by controlling the feed motion of the drill within an appropriate range during drilling. In particular, we aim to improve vibration,
This was developed with the aim of providing a control method that can reduce the noise caused by heavy cutting, and the structure of this method is to control the feed rate of one drill in a drilling machine without rotating it. A movement pulse signal supplied from a movement pulse detector provided on a drill support member sent integrally with the drill is made to correspond to an appropriate time pulse, and a pulse signal expressed as movement amount/time or time/movement amount is used. While the current movement speed signal is detected, the movement drive source of the drill support part H is set to σ: the movement amount/time or time/ The drill is driven by a scheduled movement speed signal based on a pulse signal representing the amount of movement, and the current movement speed signal and the planned movement speed signal are compared and calculated, and the driving source described in - is controlled based on the calculation result. By doing so, the feed rate of the drill can be increased or decreased within an appropriate range.

Next, an example of implementation of the present invention will be explained with reference to the drawings.

1 is a drill attached to the lower part of the spindle 2 in the main shaft head of the drilling machine; 3 is the head; 4 is a motor provided at the upper part of the knot as a rotational drive source for the drill 1; 5
is a column that supports the head in a vertically movable manner; 6 is a feed screw provided on the column;
are screwed together.

7 is a motor that serves as a drive source for the feed screw; 8 is a table located below the spindle head that fixes the work piece w;
The table 8 is one of the members for positioning the workpiece W in the drilling machine. 9 is a saddle that supports the table 8 and guides its movement; 10 is a bed on which the saddle 9 is mounted; units 1 to 10 constitute the basic structure of an example of a vertical drilling machine.

In addition, in the drilling machine, the feed mechanism of drill 1 is used.

Now, in addition to the screw 6 to be recorded, a hydraulic cylinder or
There are rack and pinion mechanisms that are operated by branching the output of the rotational drive source of the spindle, and the present invention can be applied to any of these members in the same manner as in the embodiments described below when they perform feeding movements. Since it is possible, control of the feed screw 6 will be explained below.

On the other hand, with conventional drilling machines, when performing machining such as drilling, the rotation speed of the spindle 2 is selected from within the speed range set in advance in the machine, depending on the material of the workpiece and the drill to be used. Currently, drilling is performed by rotating the feed screw 6 at a constant speed and applying rotation to the feed screw 6 to realize constant speed drill feed.

However, in cutting operations such as drilling by simply constant-speed feed of the spindle head aligned with the constant-speed rotation of the drill, the cutting edges of the drill etc. are formed at equal pitches on the circumference of the body. There is a problem in that the generated vibration resonates at a constant frequency and is likely to be amplified, and the surface roughness decreases due to this amplified vibration. This difficulty is particularly noticeable in heavy cutting.

Therefore, in the present invention, in order to solve the difficulties that have arisen in cutting by constant speed rotation of a drill and constant speed drill feed, the feed speed of the drill during cutting is adjusted according to the material of the workpiece, etc.
The selected feed rate is increased or decreased at appropriate timing to change the frequency of vibrations that occur during cutting, primarily to prevent resonance phenomena. This point will be explained below.

In the figure, reference numeral 11 is provided in relation to the sliding surface of the spatula 3 and the column 5, and the unit movement amount of the spatula 3, for example, 1 inn.
A moving pulse detector that generates 100 pulse signals per distance is used, and a length measuring device that generates pulse signals per appropriate distance is used. Incidentally, an encoder or a device having an equivalent function may be used for the feed screw 6. Then, head 3
is directly connected to the feed screw 6 via the nut portion 4J'3a, so detection of the rotation of the feed screw 6 here means detection of the amount of movement of the blade 3.

Reference numeral 12 changes the moving speed of the head 3 by making the pulse signal supplied from the pulse detector 11 correspond to a pulse signal representing an arbitrary time supplied from the clock pulse generator 13, for example, 100 pulses per second. a current speed detection unit that forms a signal representing amount/time or time/movement amount; 14;
is the variable range of the rotational output of the motor 7, the moving speed of the head 3 (+nm/rev, or mm/mi
For example, if the rotation speed of the drill l is ], 20 rpm, m
, when the feed rate is selected to be 0.25 nwn/rev, the following settings can be made.

On the other hand, the setting unit 14 generates a signal for arbitrarily increasing or decreasing the feed movement mode of the drill 1 at the selected cutting feed speed, for example, around 10% of that speed.

That is, when the selected feed rate is O, 25 mn/rev, 1 - lil 1, i.e. head 3, moves 0.50 n in 1 second.
wn movement, and the movement mode is constant, but in the present invention, for example, during feeding of the drill at the selected feed speed, 0.50 + book in 1 millisecond, or 0.50 book in 0.9 seconds. In order to arbitrarily change the movement mode, such as moving the image, 50, which represents the amount of movement of 0.50+nm, is used.
These pulses are set by a signal corresponding to 110 pulses representing 1.1 seconds or a signal corresponding to 90 pulses representing 0.9 seconds. Note that the signal representing the selected feed rate here is formed by associating 50 movement amount pulses with 100 time pulses.

In order to determine where the scheduled movement mode signal, which can be arbitrarily set as described above, is supplied to the setting section 14 according to the movement of the drill 1, the setting section 14 is provided with the pulse detector 11 and/or the time signal. A pulse signal from a pulse generator 13 is supplied, and the scheduled movement mode signal formed by this setting section 14 is stored in a scheduled speed storage section 15, for example, as an appropriate unit movement amount of the drill 1 or It is stored in correspondence with an appropriate unit movement time.

Reference numeral 16 denotes a calculation unit that successively compares the speed signals supplied from the current speed detection unit 12 and the scheduled speed storage unit 15 for each unit movement amount or unit movement time, and counts the deviation between the two;
Reference numeral 7 denotes a correction section that forms the deviation of the arithmetic section 16 into a correction signal for the fine control section 18. At the time of starting, the signal supplied from the scheduled speed storage section 15 is supplied as is to the control section 18.

In this way, the drill 1 initially starts moving at a preselected feed speed, but at the same time as the head 3 starts moving, a pulse signal supplied from the movement pulse detector 11 is sent to the current speed detection section 12, and the The above pulse signal per unit movement amount or unit movement time of the head 3 is multiplied by J1 and made to correspond to the pulse signal from the time pulse generator 8, so that the current movement speed of the drill l is determined. Detected. This current moving speed is compared and calculated with the scheduled movement mode in the calculating section 16, and a deviation signal based on the calculation result is supplied to the correcting section 17. Since the correction section 17 supplies the correction signal formed therein to the control section 18, the control signal of the motor 7 is corrected in the control section 18, and as a result,
This is because the rotation of the motor 7 is controlled so that the drill 1 moves in a scheduled movement mode at the selected feed rate.

Therefore, if the rotation of the 1,000-tuff is controlled at the selected feed rate of the drill 1, and the feed of the drill 1 is made to move at an inconstant velocity by increasing or decreasing the speed, the relative speed of the cutting edge of the drill to the rigid material will be Since the vibration is minutely increased or decreased during cutting, the vibrations generated during cutting do not have a constant period, and do not cause resonance phenomena.

In addition, in the present invention, the variable speed feed of the drill 1 is generally selected in advance according to the material of the stiffened material etc. so as not to adversely affect the surface roughness. Although it is given in the range of about ±10 to 15% of the speed, the above range may be made larger than the range of the above embodiment, or conversely may be made smaller depending on the cutting conditions such as the material of the workpiece.

In addition, the timing of changing the feed rate, such as the speed increase/decrease cycle, can of course be set arbitrarily in the setting section according to the cutting conditions such as the material of the rigid material, and can also be arbitrarily changed or newly set during machining. It is also possible to set Furthermore, it is also optional to change the feed rate either on the increasing side or on the decreasing side.

As mentioned above, since the present invention causes the member that supports the feed of the drill during cutting to move at an inconstant speed, the cycle of cutting resistance is reduced in conventional drilling machine operations such as drilling using a conventional constant-speed rotating drill and its constant-speed feed. It reduces forced vibration caused by physical fluctuations or self-excited vibration excited by this forced vibration, or realizes cutting that does not cause such vibration, and also reduces or generates noise caused by vibration as described in 1. It has the advantage of making it possible to perform cutting without causing vibrations, and furthermore, it is possible to carry out heavy cutting, which conventionally had many problems due to vibration. l In carrying out the present invention, when the drill moves at non-uniform speed,
It is also possible to change the rotational speed of the drill so that the relative speed to the rigid material each time the drill is run is non-uniform.

In addition, in the embodiment described in Section 2, the control device for the motor that is the feeding drive source for the spatula 1 and 3, which are an example of the member that feeds the drill, was constructed using a closed-loop system, but the method of the present invention uses an oven-loop system. Of course, it can also be controlled by a control device. Furthermore, the method of the present invention can be applied to any drilling machine, regardless of its mechanical type, control method, type of drive source, etc.

Since the present invention is as described above, it is extremely useful as a control method for a drilling machine.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a control block diagram showing an example of implementing the method of the present invention. DESCRIPTION OF SYMBOLS 1...Drill, 2...Spindle, 3...Head, 4...Motor of spindle 2, 5...Column, 6
...Feed screw, 7...Feed motor, 8...Table, 9...Saddle, 10...Bed, 11...Movement pulse detector, I2...Current speed detection section, 13・・・
- Clock pulse generator, 14... Setting section, 15... Planned movement speed storage section, 16... Calculating section, 17... Correction section, 18... Control section, W... Stiffened material Agent Ko Izumi
Good country

Claims (1)

[Claims] The feed rate of the drill in the drilling machine is determined by matching the movement pulse signal supplied from the movement pulse detector provided on the drill support member, which feeds the drill integrally with the drill without rotating, to an appropriate time pulse to determine the movement amount/distance. While detection is performed using a current moving speed signal based on a pulse signal expressed by time or time/travel amount, the drive source for moving the drill support member is set arbitrarily, including an increase or decrease in the moving speed of the drill. When the drill is fed, the current moving speed signal and the scheduled moving speed signal are compared and calculated based on the calculation result. A cutting control method for a drilling machine, characterized in that the feed rate of the drill is increased or decreased within an appropriate range by controlling the drive source.