JP2763147B2 - Pre-slip prevention control device for cutting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a control device for preventing slippage of a cutting machine.

(Prior Art) In a cutting machine such as a V-cut machine, pressing and fixing means for pressing and fixing the work to the processing table so that the work does not slip on the processing table due to the cutting force of the cutting tool. Is used.

However, this type of pressing and fixing means is provided with a pad member having a relatively large frictional force for fixing the work with a frictional force, for example, at the tip of a cylinder-driven fixing tool, and is arranged at a constant interval with respect to the processing table. Since it is usually constituted by a plurality of provided work fixing tools, when the work width is small, there is a problem that the pressing and fixing force is too small and the work slips.

When a work slip occurs, not only the work and the cutting tool are damaged, but also the machine itself,
It is also dangerous.

In order not to cause this kind of work slip, when the cylinder pressure is increased and the pad friction force is extremely increased, the problem of work slip is reduced, but the mechanical configuration becomes complicated and the fixing force is reduced. In the case of a work that is too large and is relatively thin, another abnormal situation may occur such that the work is distorted or bent by the cutting force.

Therefore, as a conventional countermeasure, an overload detecting device is provided for a motor for driving the cutting tool to prevent the cutting tool from being overloaded, and the number and arrangement of the work fixtures are set so that the pressing force is appropriate. Consideration may be given to optimizing

(Problems to be Solved by the Invention) However, the measures for preventing the work slip in the conventional cutting machine as described above are provisional, and the work slip cannot be reliably prevented.

For example, even if overload of the motor that drives the cutting tool is detected, work slippage can occur irrespective of the overload of the motor, and cannot be a fundamental solution.

Further, no matter how the number and arrangement of the work fixtures are optimized, it is not possible to completely fix the work to all the works having different materials, shapes and thicknesses.

Therefore, the present invention is to solve the problem of work slippage in a cutting machine and to provide a slippage prevention control device for a cutting machine capable of performing cutting work safely and with high efficiency without causing work slippage. Aim.

[Means for Solving the Problems] According to the present invention for solving the above problems, there is provided a work fixing means for pressing and fixing a work on a processing table, and a work fixed by the means for fixing the work surface to the work surface. In a slip prevention prevention control device of a cutting machine having a cutting means for performing cutting while applying a cutting force in a direction along, a processing condition setting unit for setting a processing condition of the work, and a setting unit for setting the processing condition. A fixing force calculation unit that calculates a fixing force of the work fixing unit based on a processing condition, a cutting force calculation unit that calculates a cutting force by a load amount of the processing unit, and a fixing force calculated by each of the calculation units. A comparison unit is provided which compares the cutting forces and outputs a signal for preventing slippage when the ratio of the cutting force to the fixed force becomes a certain value or more.

(Operation) In the slip prevention control apparatus for a cutting machine according to the present invention, the work fixing force of the work fixing means is compared with the cutting force of the cutting tool, and the ratio of the cutting force to the fixing force is equal to or more than a certain value. Outputs a signal to prevent slippage in advance. In general, it is sufficient for this signal to be signaled to the operator as a signal of caution for slippage. This is because an emergency stop may damage the work and the cutting tool. The emergency stop may be performed by a higher-order signal by performing the comparison in two stages.

(Example) Hereinafter, an example of the present invention will be described in detail using an example of a V-cut processing machine.

Referring to FIG. 2 and FIG. 3, a V-cut processing machine 1
Is provided with a box-shaped lower frame 3 which extends relatively long in the left-right direction (X-axis direction), and left and right side plates 5 are erected on both right and left sides of the lower frame 3. The upper portions of the left and right side plates 5 are integrally connected by an upper frame 7.

A processing table 9 is mounted on the lower frame 3 to support a plate-shaped work W to be processed.
11 are located. NC unit 13 located to the right of the machine
Is provided with a stop button 15.

Further, a plurality of brackets 17 are attached to the rear side of the lower frame 3 at appropriate intervals. A guide rail 19 extending to a position close to the processing table 9 is attached to an upper portion of each bracket 17, and the work W is gripped on the guide rail 19 and positioned in the front-rear direction (Y-axis direction). Y-axis positioning device is provided.

That is, a gear box 21 is disposed above the two brackets in the middle part of the bracket 17, and a ball screw 25 is provided between the gear box 21 and each of the bearings 23 on the front side corresponding to the gear box 21. Each is rotatably supported. Both ball screws 25 on both gear boxes 21
An appropriate coupling mechanism is incorporated so as to interlock and rotate. A pulley 27 is fixed to the rear end of the ball screw 25. The pulley 27 is rotatably connected to a servomotor My fixed to the bracket 17 via a timing belt 29.

Furthermore, a carriage 33 having a plurality of moving clamp devices 31 is supported on the guide rail 19 so as to be movable in the front-rear direction.
A nut member 35 to be screwed with 25 is attached.

Accordingly, the carriage 33 can be moved in the Y-axis direction by driving the servo motor My and rotating the ball screw 25 in an appropriate direction. In other words, the workpiece W gripped by the moving clamp device 31 can be positioned at an arbitrary position on the Y axis.

In order to machine a V-shaped groove on the upper surface of the work W positioned by the Y-axis positioning device, a slider 39 provided with a cutting tool 37 is moved vertically (in the Z-axis direction) above the machining table 9. ) Is provided with a Z-axis and X-axis positioning device that can be adjusted in position and movable in the left-right direction.

More specifically, a guide rail 41 extending in the left-right direction is attached to the upper frame 7, and a cutting head 43 that moves in the X-axis direction while the slider 39 is supported on the guide rail 41 so as to be vertically movable. Is supported. A ball screw 45 parallel to the guide rail 41 is provided between the left and right side plates 5 to move the cutting head 43 in the X-axis direction. This ball screw 45
It is connected to a servo motor Mx (not shown) via an appropriate speed reduction mechanism, and is screwed to a nut member (not shown) provided inside the cutting head 43. Therefore, the cutting head is driven by driving the servo motor Mx.
43 can be moved to any X-axis position at any speed.

In addition, a servomotor fixed to the slider 39 at an upper end thereof through an appropriate gear is provided above the slider 39.
A ball screw 49 connected to Mz and having an intermediate portion screwed to a bearing member 47 fixed to the cutting head 43 is rotatably supported. Therefore, by driving the servo motor Mz, the slider 39 provided with the cutting tool 37 at the lower end can be moved up and down to an arbitrary height at an arbitrary speed.

The cutting tool 37 has five cutting tools in this embodiment.
51 and a tool holder 53 for integrally connecting these tools 51
It is composed of The tip of the cutting tool 51 is formed in a V-shape when viewed from the X-axis direction. Each of the cutting tools 51 is attached to a cutting tool holder 53 so as to be detachable and position-adjustable. In this embodiment, when a V-shaped groove is formed on the upper surface of the work W, the groove is protruded downward toward the gazette so that the subsequent cutting bit is cut deeper than the preceding cutting bit. Therefore, when a groove is formed in the work W, the resistance acting on each cutting tool 51 becomes small. In addition, the processing from rough cutting to fine cutting can be performed by one-stroke operation of the slider 39.

After positioning the work W by the Y-axis positioning device,
In order to firmly fix the work W to the processing table 9, a fixing clamp device 55 is provided below the upper frame 7, as shown in detail in FIG. Further, the fixed clamp device 55 is provided with a plate thickness detector (not shown) for detecting this operation and detecting the thickness t of the work W while the work W is held down.

Accordingly, in FIG. 4, the fixed clamp device 55 is operated by the hydraulic cylinder 55A, the arm 55B of the fixed clamp device 55 is rotated around the pin 55C, and the pad 55D provided at the tip thereof is placed on the upper surface of the work W. By pressing, the work W can be fixed at a predetermined pressing force on the upper surface side of the processing table 9. Further, the plate thickness t can be detected in a state where the work W is pressed.

To prevent the ball screw 45 from bending by its own weight,
Usually, while supporting the ball screw 45 from below,
When passing slider 39, move back
A plurality of screw support devices 57 for avoiding interference with 39 are provided at appropriate intervals in the left-right direction.

With the above configuration, the positioning is performed by the Y-axis positioning device,
After adjusting the height position of the slider 39 with respect to the work W fixed by the fixed clamp device 55, the cutting head 43 is moved in the X-axis direction while appropriately controlling the height of the slider 39, so that the cutting tool 51 can be used. The V-shaped groove processing is performed on the work W.

FIG. 1 shows a block diagram of a slip prevention control device applied to the V-cut processing machine 1.

As shown in the figure, the control device of this example includes a processing condition setting unit 59.
In addition to the processing control unit 61 that performs normal processing control based on the processing conditions set in, a fixed force calculation unit 63, a cutting force calculation unit 65,
A comparison unit 67, a motor current detection unit 69, and a slip pre-processing unit 71 are provided.

FIG. 5 is a flowchart showing a work slip pre-processing method.

The fixing force calculation unit 63 is configured to operate the fixed clamp device 55 in accordance with the shape of the workpiece W,
Is calculated (step 501). Cutting force calculator 6
5 calculates the cutting force B from the current value i of the servo motor Mx detected by the motor current detector 69 (step 50).
2). The comparison unit 67 compares the fixing force A and the cutting force B in step 503, detects a state in which the work W is likely to slip, and outputs a signal C. The slip pre-processing unit 71 performs
Turn on LED lamps, output warning signals to CRT,
Alternatively, a buzzer sounds or an emergency stop is applied (step 504).

In FIG. 4, S is the cylinder sectional area, P is the hydraulic pressure,
If F is the cylinder pressure, F = S · P.

Therefore, assuming that the distance between the arm 55B and the pin 55C to each operating point is x, y, the pressing force Q per fixed clamp device is as follows: Q = xF / y = xSP / y (1)

Here, the friction coefficient above and below the pad 55D is μ ₁ , μ
_2, when the number of clamp device 55 and n, (thrust cutting direction) fixing force A is, A = n · (μ · + μ 2) Q , and the if the constant is _{k 1 A = k 1 · n} · P (2) (where k ₁ = (μ ₁ + μ ₂ ) x / y). That is, the fixing force A is proportional to the product of the hydraulic pressure P of the cylinder 55A and the operation number n.

On the other hand, assuming that the current value of the servo motor Mx is I, the lead L of the ball screw, the efficiency is η, and the generated torque is T, 2πηT = BL and T = k ₂ I (k ₂ is a torque constant). = 2πη · k ₂ I / L, B = k ₃ · I (3) (where k ₃ = 2πη · k ₂ / L).

Therefore, the fixing force A is known from the equation (2) based on the number n of the fixed clamps set according to the work length, and a value a · A obtained by appropriately multiplying this by a number a smaller than 1 is shown in the equation (3). By comparing with the cutting force B, the work W basically slips when A <B, and this can be known in advance.

FIG. 6 shows the relationship between the fixing force A and the cutting force B.

In the figure, a danger region is set between a workable range where the ratio of the fixing force A is large and a work slip region where the ratio of the cutting force is large, and the maximum current I ₀ is set at the boundary between the processing region and the danger region.
Is determined, processing within the processable range becomes possible.

More specifically, as shown in FIG. 7, currents I ₁ and I ₂ smaller than the current value I ₀ that defines the dangerous area are determined, and when the current I of the servo motor Mx becomes I ₁ , the occurrence of slippage occurs. The danger can be notified by LED lamp or buzzer.
Further, it is possible to apply an emergency stop for instance when the current I becomes I ₁ is larger than I _2.

The operator turns on the LED lamp and sounds a buzzer.
Current I becomes I _1, i.e., know that there is a risk of slippage, to observe the processing state of the work, generally or perform replacement of V-cut processing after the end of the byte 51 of the workpiece W, the cutting oil By performing the adjustment, the cutting force can be reduced in the next processing. At this time, the user can operate the stop button 15 to temporarily stop the cutting head 43 at the program block at the end of the V-cut.

Furthermore, in this example, still the current I is the emergency stop when a I _2, accident of course by slippage, also detect other abnormal conditions, it can prevent major accidents .

In the above embodiment, the fixing force A is based on only the pressing force of the fixed clamp device 55, but the fixing force of the movable clamp device 31 may be applied to this.

Further, although the torque generated due to the displacement of the fixing force A and the cutting force B in the Y-axis direction is not described, the fixing force A and the cutting force B are calculated using an arithmetic expression appropriately set according to the design conditions of the machine. Can be calculated.

Further, the data serving as the calculation reference can be stored in a database, and the calculation processing can be performed quickly according to the processing content of the work W.

This embodiment is not limited to the above embodiment,
The present invention can be implemented in an appropriate mode by making an appropriate design change.

[Effect of the Invention] As described in detail above, the present invention is a work slip advance prevention control device for a cutting machine as described in the claims, so that the slip can be easily reduced without providing a special sensor. It is possible to detect in advance and prevent a serious accident caused by slippage of the work.

Also, when detecting work slip by comparing the work fixing force and the cutting force, the comparison is performed in multiple stages, and only a warning is output with a lower signal, and an emergency stop is output with a higher signal. For example, the processing method can be changed so that a slip does not occur in the subsequent processing by an alarm, and safe and highly efficient processing can be performed without lowering the processing efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a work slip prevention control apparatus according to an embodiment of the present invention, FIG. 2 is a front view of a V-cut processing machine, FIG. 3 is a right side view thereof, and FIG. Is an enlarged explanatory view of the fixed clamping device, FIG. 5 is a flowchart of a work slip pre-processing method, FIG. 6 is an explanatory view showing a relationship between a fixing force and a cutting force, and FIG. 7 is an explanatory view of a current comparison method. 51 Byte 55 Fixed clamp device 59 Machining condition setting unit 63 Fixed force calculation unit 65 Cutting force calculation unit 67 Comparison unit 69 Motor current detection unit 71 Slip pre-processing unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B23Q 3/00 B23Q 17/00-17/09 B23Q 11/00 B23D 1/08

Claims (1)

(57) [Claims] A work fixing means for pressing and fixing a work on a work table, and a cutting means for cutting the work fixed by the means while applying a cutting force in a direction along the work surface. In the slip prevention prevention control device of the cutting machine, a processing condition setting unit that sets processing conditions of the work, and a fixing force calculation that calculates a fixing force of the work fixing unit based on the processing conditions set in the setting unit. And the cutting force calculation unit that calculates the cutting force by the load amount of the processing means, and compares the fixed force and the cutting force calculated by the two calculation units, and the ratio of the cutting force to the fixed force is equal to or greater than a certain value. A control device for preventing slippage of a cutting machine, comprising a comparison unit for outputting a signal for preventing slippage when the slippage occurs.