EP0738197B1 - Grinding method and apparatus - Google Patents

Grinding method and apparatus Download PDF

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Publication number
EP0738197B1
EP0738197B1 EP94904232A EP94904232A EP0738197B1 EP 0738197 B1 EP0738197 B1 EP 0738197B1 EP 94904232 A EP94904232 A EP 94904232A EP 94904232 A EP94904232 A EP 94904232A EP 0738197 B1 EP0738197 B1 EP 0738197B1
Authority
EP
European Patent Office
Prior art keywords
workpiece
grinding wheel
grinding
speed
feed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94904232A
Other languages
German (de)
French (fr)
Other versions
EP0738197A1 (en
Inventor
Geoffrey Ian Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Intermec Europe Ltd
Original Assignee
Unova UK Ltd
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Filing date
Publication date
Application filed by Unova UK Ltd filed Critical Unova UK Ltd
Publication of EP0738197A1 publication Critical patent/EP0738197A1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/02—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/007—Weight compensation; Temperature compensation; Vibration damping

Definitions

  • This invention relates to a method of grinding a workpiece having a cylindrical surface and to apparatus for carrying out said method.
  • chatter-marks can be reduced by absolute truing of the grinding wheel, but this is time consuming and expensive, especially when the grinding surface is a super-abrasive such as diamond or CBN.
  • the wheel and workpiece rotational speeds are controlled to minimise the growth of charter and to optimise the grinding process. This is achieved by measuring the precession of lobes about the grinding wheel and workpiece and determining an exponential charter growth index using the measured lobe precessions.
  • the index is stated to be a measure of the rate of growth of charter and is also a measure of the stability of the grinding process concerned.
  • a control unit is used to generate control signals for the motors which rotate the grinding wheel and workpiece respectively.
  • a method of grinding a cylindrical workpiece surface in which the speed of rotation of the grinding wheel and/or the speed of rotation of the workpiece is changed in a relatively slow manner one or more times during the final stage of grinding, such rotational speed change extending into the final dwell period in which sizing occurs, thereby to reduce chatter-marks on the workpiece, the speed change effected not being dependent on vibration sensing of the grinding wheel or the workpiece.
  • the method and apparatus of the invention may be applied to internal as well as external grinding.
  • the rotational speed variation is preferably practised by rotational speed change which includes one or more changes in the rotational speed of the workpiece.
  • any change made will usually be decelerative.
  • the rotational speed of the grinding wheel is kept constant.
  • the one or more rotational speed changes may be initiated either after a predetermined number of rotations of the workpiece where the number of turns per grinding cycle is controlled and/or at a predetermined feed distance before the feed position for final sizing, as indicated in more detail below.
  • the speed variations effected may therefore be linear, reduce or increase at a rate relative to the above variables, or be of other controlled forms such as sinusoidal.
  • the speed change is normally initiated during the slow approach to size feed and always extends into the final dwell period in which sizing occurs.
  • Figure 1 is a typical feed diagram for the grinding wheel in a grinding process for grinding a cylindrical workpiece.
  • the grinding wheel feed includes a fine feed period 10 immediately prior to a stationary final dwell period 12 (size dwell) in which sizing occurs.
  • a change in the rotational speed of the workpiece is initiated in the fine feed period, and this speed change or one or more further speed changes is extended into at least part of the final dwell period 12.
  • the means 22 is preferably constituted by a servo-controller, which automatically initiates one or more changes in the workspeed at the aforesaid time and for the aforesaid period, for example dependently on the feed position, the number of turns of the workpiece in the grinding cycle, and/or component size.
  • the or each change effected is not sudden, but is a relatively slow change which may be linear, sinusoidal or of any other desired form.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding Of Cylindrical And Plane Surfaces (AREA)
  • Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

Description

Field of the invention
This invention relates to a method of grinding a workpiece having a cylindrical surface and to apparatus for carrying out said method.
Background to the invention
It is well known that, when a cylindrical workpiece is being ground, the grinding process produces vibrations which generate lobes on the workpiece surface. This phenomenon is commonly known as chattering, and the resulting distortions on the workpiece are known as chatter-marks.
To some extent chatter-marks can be reduced by absolute truing of the grinding wheel, but this is time consuming and expensive, especially when the grinding surface is a super-abrasive such as diamond or CBN.
In the method of optimising grinding described in US Patent 4604834, the wheel and workpiece rotational speeds are controlled to minimise the growth of charter and to optimise the grinding process. This is achieved by measuring the precession of lobes about the grinding wheel and workpiece and determining an exponential charter growth index using the measured lobe precessions. The index is stated to be a measure of the rate of growth of charter and is also a measure of the stability of the grinding process concerned. Using signal feedback processing and frequency multiplication techniques, from information derived from tachometers, a control unit is used to generate control signals for the motors which rotate the grinding wheel and workpiece respectively.
It is an object of the present invention to provide a method of and apparatus for reducing the tendency for generation of chatter-marks during grinding.
The invention
According to one aspect of the invention, there is provided a method of grinding a cylindrical workpiece surface in which the speed of rotation of the grinding wheel and/or the speed of rotation of the workpiece is changed in a relatively slow manner one or more times during the final stage of grinding, such rotational speed change extending into the final dwell period in which sizing occurs, thereby to reduce chatter-marks on the workpiece, the speed change effected not being dependent on vibration sensing of the grinding wheel or the workpiece.
According to another aspect of the invention, there is provided the apparatus defined in claim 2.
The method and apparatus of the invention may be applied to internal as well as external grinding.
The rotational speed variation is preferably practised by rotational speed change which includes one or more changes in the rotational speed of the workpiece.
If the speed variation includes change in the rotational speed of the grinding wheel, any change made will usually be decelerative. Preferably, however, the rotational speed of the grinding wheel is kept constant.
The one or more rotational speed changes may be initiated either after a predetermined number of rotations of the workpiece where the number of turns per grinding cycle is controlled and/or at a predetermined feed distance before the feed position for final sizing, as indicated in more detail below.
Thus, the possibilities for workspeed variation are limitless if its rotational speed is servo-controlled relative to time, grinding wheel feed position, component size and/or number of component turns.
The speed variations effected may therefore be linear, reduce or increase at a rate relative to the above variables, or be of other controlled forms such as sinusoidal. However, the speed change is normally initiated during the slow approach to size feed and always extends into the final dwell period in which sizing occurs.
Description of embodiment
The practical implementation of the method and apparatus of the invention is exemplified with reference to the accompanying drawings, in which:-
Figure 1
is a graph showing the feed of the grinding wheel in terms of workpiece distance v time; and
Figure 2
is a much simplified diagram of a grinding machine.
Figure 1 is a typical feed diagram for the grinding wheel in a grinding process for grinding a cylindrical workpiece.
The grinding wheel feed includes a fine feed period 10 immediately prior to a stationary final dwell period 12 (size dwell) in which sizing occurs.
In accordance with the invention, a change in the rotational speed of the workpiece is initiated in the fine feed period, and this speed change or one or more further speed changes is extended into at least part of the final dwell period 12.
In the simplified grinding machine shown in Figure 2, wherein the grinding wheel is referenced 14, the wheel feed indicated at 16, the workpiece at 18 and the workpiece support at 20, a means 22 is incorporated for changing the rotational speed of the workpiece 18, as aforesaid.
The means 22 is preferably constituted by a servo-controller, which automatically initiates one or more changes in the workspeed at the aforesaid time and for the aforesaid period, for example dependently on the feed position, the number of turns of the workpiece in the grinding cycle, and/or component size.
The or each change effected is not sudden, but is a relatively slow change which may be linear, sinusoidal or of any other desired form.

Claims (9)

  1. A method of grinding a cylindrical workpiece surface in which the speed of rotation of the grinding wheel and/or the speed of rotation of the workpiece is changed in a relatively slow manner one or more times during the final stage of grinding, such rotational speed change extending into the final dwell period in which sizing occurs, thereby to reduce chatter-marks on the workpiece, the speed change effected not being dependent on vibration sensing of the grinding wheel or the workpiece.
  2. Apparatus for grinding a cylindrical workpiece surface comprising a grinding machine having a grinding wheel, a grinding wheel feed, a grinding wheel feed controller, means for rotating the grinding wheel, a workpiece support, means for rotating the workpiece, and control means adapted to change automatically the speed of rotation of the grinding wheel and/or of the workpiece in a relatively slow manner, during the final stage of grinding and extending into the final dwell period in which sizing occurs to enable, the speed of rotation of the grinding wheel and/or the workpiece to be changed one or more times in order to reduce chatter-marks on the workpiece, the speed change effected not being dependent on vibration sensing of the grinding wheel or the workpiece.
  3. A method according to claim 1 or apparatus according to claim 2 in which the rotational speed change includes one or more changes in the rotational speed of the workpiece.
  4. A method or apparatus according to claim 1 or claim 2 in which the speed change is decelerative.
  5. A method or apparatus according to any one of claims 1 to 4 in which the speed of the grinding wheel is kept constant.
  6. A method or apparatus according to any one of claims 1 to 5 in which one or more rotational speed changes are initiated either after a predetermined number of rotations of the workpiece, where the number of turns per grinding cycle is controlled, and/or at a predetermined feed distance before the feed position for final sizing.
  7. A method or apparatus according to any one of claims 1 to 5 in which the rotational speed is servo-controlled relative to time, grinding wheel feed position, component size and/or number of component turns.
  8. A method or apparatus according to claim 6 or claim 7 in which the speed variations effected are linear or sinusoidal, and reduce or increase at a rate relative to the said variables.
  9. A method or apparatus according to any one preceding claim in which the speed change is initiated during the slow approach to size feed.
EP94904232A 1992-07-18 1994-01-13 Grinding method and apparatus Expired - Lifetime EP0738197B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9215349A GB2268895B (en) 1992-07-18 1992-07-18 Grinding method and apparatus
PCT/GB1994/000047 WO1995019241A1 (en) 1992-07-18 1994-01-13 Grinding method and apparatus

Publications (2)

Publication Number Publication Date
EP0738197A1 EP0738197A1 (en) 1996-10-23
EP0738197B1 true EP0738197B1 (en) 1999-10-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP94904232A Expired - Lifetime EP0738197B1 (en) 1992-07-18 1994-01-13 Grinding method and apparatus

Country Status (6)

Country Link
EP (1) EP0738197B1 (en)
AU (1) AU5837194A (en)
DE (1) DE69421094T2 (en)
ES (1) ES2138068T3 (en)
GB (1) GB2268895B (en)
WO (1) WO1995019241A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2291608B (en) * 1994-07-23 1996-11-06 Western Atlas Uk Ltd Grinding method and apparatus
DE60030790T2 (en) * 1999-10-27 2007-01-11 Cinetic Landis Grinding Ltd. Method for grinding a workpiece with which constant time gap volumes are achieved
CN108555697A (en) * 2017-11-02 2018-09-21 中国航发哈尔滨东安发动机有限公司 A kind of method for grinding of rotator tip
JP2023000307A (en) * 2021-06-17 2023-01-04 株式会社ディスコ Grinding apparatus

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH595187A5 (en) * 1975-12-20 1978-02-15 Studer Ag Fritz
DE3375464D1 (en) * 1982-12-16 1988-03-03 Centre Rech Tech Ind Fab Metal Method and device for adjusting any work piece by removing material by means of a griding wheel
US4604834A (en) * 1985-10-03 1986-08-12 General Electric Company Method and apparatus for optimizing grinding

Also Published As

Publication number Publication date
EP0738197A1 (en) 1996-10-23
AU5837194A (en) 1995-08-01
GB2268895B (en) 1995-06-28
GB9215349D0 (en) 1992-09-02
ES2138068T3 (en) 2000-01-01
DE69421094T2 (en) 2000-01-20
WO1995019241A1 (en) 1995-07-20
GB2268895A (en) 1994-01-26
DE69421094D1 (en) 1999-11-11

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