AN APPARATUS FOR DRESSING A GRINDING WHEEL

Abstract

An apparatus for dressing a grinding wheel mounted thereon by creating structures on the surface of a, in particular cylindrical, grinding surface of the grinding wheel The apparatus includes a dressing tool holder arranged for accommodating a dressing tool in a dressing position, a controllable actuator for adjusting the position of the tool holder within the apparatus in at least one direction, a grinding wheel support for rotatably supporting a grinding wheel to be dressed The apparatus further includes a mechanism for monitoring an individual structure, created by the dressing tool on the surface of the grinding wheel, and a mechanism for monitoring a circumferential position and/or the rotary speed of the grinding wheel, and a mechanism for controlling the actuator, adapted to control the actuator as a function of the monitored structure and the monitored circumferential position and/or rotary speed.

Claims

1. An apparatus for dressing a grinding wheel mounted thereon by creating structures on the surface of a, in particular cylindrical, grinding surface of the grinding wheel, the apparatus comprising: a dressing tool holder arranged for accommodating a dressing tool in a dressing position, a controllable actuator for adjusting the position of the tool holder (6) within the apparatus in at least one direction, a grinding wheel support for rotatably supporting a grinding wheel to be dressed, the apparatus further includes: means for monitoring an individual structure, created by the dressing tool on the surface of the grinding wheel, and means for monitoring a circumferential position and/or a rotary speed of the grinding wheel, and means for controlling the actuator, adapted to control the actuator as a function of the monitored structure and the monitored circumferential position and/or rotary speed.

2. An apparatus according to claim 1, wherein the means for monitoring an individual structure are adapted to monitor the individual structure at the instant moment during creation of this respective structure.

3. An apparatus according to claim 1, wherein the means for monitoring the structure comprise an acoustic sensor for monitoring noise, which is generated during creating of the respective structure, the acoustic sensor is in particular attached to the dressing tool and/or the dressing tool holder.

4. An apparatus according to claim 1, further comprising: an analyzing unit, adapted to reconstruct a structure created on the surface of the grinding wheel, based on the information provided by the means for monitoring an individual structure and the means for monitoring a circumferential position and the means for monitoring the rotary speed or circumferential position of the grinding wheel.

5. An apparatus according claim 1, wherein the apparatus comprises further means adapted for comparing the monitored structure with a given predetermined structure and means adapted for adjusting at least a control pulse for controlling the actuator of the dressing tool and/or a motor for driving the grinding wheel based on the result of the comparison.

6. A method for controlling an apparatus for dressing a grinding wheel by creating structures onto a, in particular cylindrical, grinding surface of the grinding wheel, the apparatus comprising: a dressing tool holder arranged for accommodating a dressing tool in a dressing position, a controllable actuator for adjusting the position of the tool holder within the apparatus in at least one direction, a grinding wheel support for rotatably supporting a grinding wheel to be dressed, the method comprising the following steps: monitoring an individual structure created on the surface of the grinding wheel, monitoring the circumferential position and/or the rotary speed of the grinding wheel, and controlling the actuator of the dressing tool as a function of the monitored structure and the monitored circumferential position and/or rotary speed.

7. The method according to claim 6, wherein the step of comparing the monitored structure with a predetermined structure, wherein the step of controlling the actuator of the dressing tool is based on the result of this comparison.

8. The method according to claim 6, wherein the respective structure is monitored at the instant moment during creation of this respective structure.

9. The method according to claim 6, wherein the actual rotary speed or circumferential position of the grinding wheel is controlled on the basis of a predetermined rotary speed.

Description

EXAMPLE EMBODIMENT OF THE INVENTION

[0023] Further embodiments of the invention are subsequently disclosed with reference to the accompanied figure. The figure show a block diagram of an apparatus according to the invention.

[0024] The apparatus 1 comprises a grinding wheel support 14 for rotatably supporting a grinding wheel 2 to be dressed within the apparatus 1. A motor 20 drives the grinding wheel 2 into rotation. A magnetic circumferential position sensor 8 is provided to monitor the actual circumferential position 19 of grinding wheel 2. By differentiating the several monitored circumferential position values a rotary speed of the grinding wheel is obtained.

[0025] A dressing tool 4 comprise a diamond tip 5, which during the dressing process gets in contact with the surface 3 of the grinding wheel 2. The dressing tool 4 is supported by a dressing tool holder 6. The position of the dressing tool holder 6 can be manipulated by an actuator 7 in various directions. In particular by varying the position of the dressing tool holder 6 in x-direction, the depth of immersion of the diamond tip 5 into the surface 3 of the grinding wheel 2 is adjusted.

[0026] A control unit 10 provides control pulses 16 for the dressing tool actuator 7. The control unit 10 is provided with data concerning the predetermined surface 3.sub.P, which has to be created on the grinding wheel 2. Several predetermined structures 11 are provided within these data. Synchronization with the actual circumferential position of the grinding wheel 2 is provided by the circumferential position signal 19 of the grinding wheel 2.

[0027] An acoustic sensor 13 is provided for recording noise 18 occurring during immersion of the diamond tip 5 into the surface 3. Based on the immersion depth, the force, which is applied on the tip 5, the duration of the immersion and the area of the immersion, noises of different spectra 18 are generated. So when different structures are created on the surface noises of different frequencies and volumes, subsequently summarized under the term noise spectra 18, occur. A library of different noise spectra 18 is deposited in a database 15, along with details of structures 12 assigned thereto. By comparing the recorded noise spectra 18 with a noise spectra 18 deposited in the database 15 under consideration of the rotary speed signal 19 of the grinding wheel 2, a structure 12 can be determined, which is similar to the structure which was created during the recording of the respective noise 18. This determination is performed by an analysing unit 9, which has access to the data base 15. As a result the analysing unit 9 establishes an observed surface image 3.sub.O comprising the structures 12 as monitored.

[0028] Due to wear of the dressing tool 4 or wear of bearing of the grinding wheel support 14 it may occur, that the accuracy of the dressing process is reduced in the course of time. As an example FIG. 1 shows in the observed surface 3.sub.O a structure 12, which deviates from the predetermined structures 11. This indicates an undue wearout of the dressing tool 4. This wearout can be compensated by a respective change in the controlling of the actuator 7. For example the loss of diamond particles at the tip 5 can be compensated by an increased feed rate of the actuator 7 in x-direction. The apparatus and method according to the present invention provides the possibility of adapting the feed rate within a control circuit in real-time.

LIST OF REFERENCE SIGNS

[0029] 1 apparatus

[0030] 2 grinding wheel

[0031] 3 surface of grinding wheel

[0032] 4 dressing tool

[0033] 5 diamond tip

[0034] 6 dressing tool holder

[0035] 7 dressing tool actuator

[0036] 8 circumferential position sensor

[0037] 9 analysing unit

[0038] 10 control unit

[0039] 11 predetermined structure

[0040] 12 monitored structure

[0041] 13 acoustic sensor

[0042] 14 grinding wheel support

[0043] 15 database

[0044] 16 control pulse for dressing tool actuator

[0045] 17 control pulse for motor

[0046] 18 noise spectrum

[0047] 19 circumferential position and/or rotary speed

[0048] 20 motor