JPH0557609A - Dressing device for grinding machine - Google Patents

Abstract

PURPOSE:To automatically perform dressing of a grinding wheel in a grinding machine used for outer diameter grinding of a throw away chip and the like. CONSTITUTION:Grinding resistance of a grinding wheel 16 is monitored, the condition of a grinding face is judged by magnitude of the value, and according to the result of judgement, an alarm is raised or a dressing grinding wheel 20 is relatively approached to the grinding wheel 16 so as to automatically perform dressing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine used for grinding the outer circumference of a throw-away tip, and more particularly to a grinding machine which automatically dresses a grindstone.

[0002]

2. Description of the Related Art Conventionally, in manufacturing indexable inserts, a grinding machine is used to finish the outer periphery into a predetermined shape or to attach a blade to the outer periphery.

Further, in order to prevent deterioration of the ground surface of the grindstone due to the above grinding process, it is necessary to perform a dressing process on the ground surface periodically.

[0004]

By the way, the dressing time of the grindstone cannot always be uniformly determined, and due to insufficient dressing, the processing time is extended, the grindstone load is increased, or the dressing is excessive. This causes problems such as unnecessary interruption of grinding work and excessive wear of the grindstone. Further, since the timing is artificially determined, there is a problem that individual differences easily occur among workers. An object of the present invention is to perform proper dressing and perform efficient grinding work.

[0005]

In order to achieve such an object, in claim 1 of the present application, a grindstone, a driving means for driving the grindstone, a dressing means for dressing a grinding surface of the grindstone, and It is composed of a sensor for detecting the grinding resistance and a discriminating means for comparing the detection value of the sensor with a reference value and outputting the result.

Further, according to a second aspect of the present invention, a grindstone, a driving means for driving the grindstone, a dressing means for dressing the grind surface of the grindstone, and the dressing means are relatively close to the grind surface, or It is composed of a dressing operation means for separating from each other, a sensor for detecting a grinding resistance of the grindstone, and a control means for controlling the dressing operation means according to a detection value of the sensor.

[0007]

According to the above construction, it is possible to judge the quality of the grinding surface from the measurement result of the grinding resistance of the grindstone. Further, by utilizing this determination result, the operator is informed of the necessity of dressing or the dressing operation means is controlled, so that the grindstone can be always maintained in a good state.

[0008]

1 and 2 show an embodiment of the present invention.

Reference numeral 10 is a motor, and this motor 1
The rotation of 0 is caused by the grinding wheel 16 through the pulleys 12 and 14.
To be transmitted to. On the other hand, reference numeral 18 denotes a work such as a throw-away tip, which is a first work described later.
The feeding device can move in the direction of arrow a or b in the figure. A dressing grindstone 20 is provided near the grinding surface 18 of the grinding grindstone 16, and the dressing grindstone 20 is driven by a motor 22. Similarly to the work, the dressing grindstone 20 is also moved in the direction of arrow C or D in the figure (direction closer to or away from the grinding surface) by a second feeding device (not shown). Further, the motor 10 is adapted to receive power supply from a power supply 24.

The chuck 28 for supporting the work is supported by a feeding device 30. The feed device 30 is constituted by, for example, a feed screw mechanism. In the case of the embodiment, a female screw 34 which is screwed to a screw shaft 32 connected to the chuck 28 is driven by a motor 40 via gears 36 and 38. As a result, the chuck 28 moves up and down.

The load current of the motor 40 constituting the feeding device 30 is detected by the sensor 42. The detected current signal is supplied to the filter 44,
By this filter 44, only DC or extremely low frequency signals are transmitted to the controller 48. That is, steady vibration and sudden large current are cut off. Further, the load of the sensor 42 is large when the cutting resistance of the workpiece 18 is large and small when the cutting resistance is small. Therefore, in reality, the cutting resistance detector or mechanical strain caused by the cutting resistance is reduced. It suffices to perform the function as a detector for detecting. For example, a strain gauge (strain gauge) 48 is provided in the chuck 28 and a part of its supporting mechanism, and the output of the strain gauge 48 is indicated by a broken line 44 in the figure. The same function can be achieved by supplying it to the controller 46 via the. Further, the increase of cutting resistance is caused by the grindstone 16 and
Since the strain of the mechanical system supporting the shaft 34 is also increased, the cutting resistance may be detected using strain gauges provided on these.

Next, the contents of the control performed by the controller 34 will be described together with the operation of the dressing device.

Step 1 Starts when the grinding machine is activated.

Step 2 The dressing flag DFL set when the dressing is required is judged, and if DFL = 0, that is, if the dressing is not required, the process proceeds to step 3, and if necessary, the process proceeds to step 20.

Step 3 When the work 18 is fed to approach the grindstone 16, the motor 1
The load of 0 gradually increases. Further, 1 is substituted for the number of grinding times n of the workpiece 18, and zero is substituted for the abnormal vibration frequency j.

Step 4 Grinding resistance measured by the sensor 42 or the strain gauge 48 or the measured value δ concerning the strain of the mechanical system accompanying this.
Is supplied to the controller 46 after the vibration component is removed by passing through the filter 44. Therefore, even if a large grinding resistance or mechanical system distortion suddenly occurs due to a partial defect of the work or the grindstone, an unexpected external force, etc., this vibration is ignored by the controller 46.

Step 5 It is judged whether or not the measured value δ exceeds the reference value C. The reference value C is set as an absolute value or a relative value, for example, based on the measured value of the grinding resistance or strain at no load. Then, in the state where the grinding surface is deteriorated, the measured value becomes large when the feed of the work 18 is constant.

Step 6 The number j of times the measured value δ exceeds the reference value C is incremented.

Step 7 It is judged whether or not a predetermined amount has been fed, that is, whether or not the grinding of a certain surface is completed, and the condition is that the grinding is completed, and the process proceeds to the next step. On the other hand, if not completed, the process returns to step 4 to continue the grinding.

Step 8 The number of grinding times n is incremented.

Step 9 It is judged whether or not the number of grinding times n has reached the set value N. If not, the process returns to the step 4, and if it does, the process proceeds to the next step 10. The set value N referred to here is the number of portions to be polished in the throwaway tip, for example, N = 4 when the planar shape is a quadrangle, and N = when the planar shape is a triangle.
It is set to 3.

Step 10: Compare the over-vibration frequency j with the reference value J. If it exceeds the reference value J, proceed to step 11 to set the dressing flag DFL to 1, otherwise proceed to step 12 to proceed to the dressing flag DFL. Is set to 0, and in any case, the process proceeds to step 13 to end the control. The reference value J
Is set to a value equal to or less than the number of grinding times N, for example, J =
When set to 1, even when over-vibration occurs in machining on one side while machining one chip,
When it is determined that dressing should be performed quickly, and when the value is set to a value greater than 1, a sudden overload will not be determined as deterioration of the polishing surface.

Then, the grinding of one work is completed by the above steps. On the other hand, in step 2, when the dressing flag DFL is set to 1, the process proceeds to the next step.

Step 20 The dressing grindstone 20 is brought close to the grinding surface of the grindstone 16.

Step 21 The process proceeds to the next step on condition that the dressing grindstone 20 has been fed by a predetermined amount. The feeding of the dressing grindstone 20 is determined based on whether or not the dressing grindstone 20 has been fed by a preset distance, or whether the load on the dressing grindstone 20 has exceeded a predetermined value.

Step 22 When the predetermined amount is fed or when the predetermined dressing is completed, the feeding is stopped and the dressing flag DF
Set 0 to L.

By such processing, the surface condition of the grindstone 20 can be constantly monitored and dressing can be performed at an optimum time.

In the embodiment, the dressing grindstone is automatically moved closer to the grinding grindstone for dressing according to the judgment of the dressing timing by the controller. However, the judgment result is limited to the output of the dressing command, Needless to say, an alarm or the like may be activated to manually perform dressing.

Further, the location for detecting the grinding resistance and the strain associated therewith may be, for example, a housing of the bearing, a chuck for supporting the work, a feed mechanism, etc., other than the bearing portion of the above embodiment. Of course.

FIG. 3 shows another embodiment of the present invention. In this embodiment, a tool rest 50 that supports the workpiece 18
Is provided with a three-component force meter 52 that detects deformation of the tool rest 50 in three directions and converts it into an electric signal, and supplies a signal output from the three-component force meter 52 to the controller 34 via the filter 32. It was done. The three-component dynamometer 5
The reference numeral 2 is composed of, for example, strain gauges arranged in different detection directions, and converts the deformation of the tool rest 50 into an electric signal. Also in this embodiment, the dressing timing can be accurately determined based on the change in the electric signal of the strain, as in the case of the first embodiment.

In the above embodiment, the grinding resistance is detected via the load of the work feed mechanism. However, in the case of a system in which the work is fixed and the feed mechanism is provided on the grinding wheel side, It suffices to detect the grinding resistance through the load of the grinding wheel feed mechanism and operate the feed mechanism to bring the grinding wheel closer to the dressing wheel according to the judgment based on this grinding resistance.

[0032]

As is apparent from the above description, the present invention is
By detecting the grinding resistance of the grindstone and comparing it with a reference value, dressing can be performed automatically, so if the grinding surface deteriorates, it can be quickly judged and the grinding surface will always be ideal. It is possible to efficiently process the throw-away tip while maintaining the above condition. Further, since the judgment of the dressing time or the execution of the dressing is uniformly executed based on the set value, there is an effect that a stable quality can be realized regardless of the experience and skill of the operator.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an example.

FIG. 2 is a flowchart showing an operation of the controller shown in FIG.

FIG. 3 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 10 Motor 16 Grindstone 18 Workpiece 20 Dressing Grindstone 28 Detector 30 Feed Device 32 Screw Shaft 42 Sensor 44 Filter 46 Controller 48 Strain Gauge 50 Turret 52 52 Tripartite Force Meter

Claims (2)

[Claims] 1. A grindstone, a driving means for driving the grindstone, and a dressing means for dressing a grinding surface of the grindstone,
A dressing device for a grinding machine, comprising: a sensor that detects a grinding resistance of the grindstone; and a determination unit that compares a detection value of the sensor with a reference value and outputs the result. 2. A grindstone, a driving means for driving the grindstone, and a dressing means for dressing a grinding surface of the grindstone,
Dressing operating means for moving the dressing means relatively close to or away from the grinding surface, a sensor for detecting a grinding resistance of the grindstone, and a control means for controlling the dressing operating means by a detection value of the sensor. A dressing device for a grinding machine, which comprises: