GB2116085A - Grinding machine and method of grinding a workpiece - Google Patents
Grinding machine and method of grinding a workpiece Download PDFInfo
- Publication number
- GB2116085A GB2116085A GB08305795A GB8305795A GB2116085A GB 2116085 A GB2116085 A GB 2116085A GB 08305795 A GB08305795 A GB 08305795A GB 8305795 A GB8305795 A GB 8305795A GB 2116085 A GB2116085 A GB 2116085A
- Authority
- GB
- United Kingdom
- Prior art keywords
- dressing
- wheel
- grinding
- workpiece
- grinding wheel
- 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.)
- Withdrawn
Links
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
- B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Grinding-Machine Dressing And Accessory Apparatuses (AREA)
Abstract
A grinding machine comprising a grinding wheel (6); means for rotating the grinding wheel (6); a dressing wheel (10); means (M3) for rotating the dressing wheel (10); means (M2,7) for maintaining the grinding wheel (6) and the dressing wheel (10) in a dressing position in which in operation the dressing wheel (10) dresses the grinding wheel (6); a dressing device (13) which may be a wheel or diamond tip; and means (M4,12) for maintaining the dressing wheel (10) and the dressing device (13) in a dressing position in which in operation the dressing device (13) dresses the dressing wheel (10). <IMAGE>
Description
SPECIFICATION
Grinding machine and method of grinding a work
piece
This invention concerns a grinding machine and a
method of grinding a workpiece.
When a workpiece is ground by means of a
grinding wheel in whose circumference there are
embedded grains of abrasive material, the abrasion
of these grains ultimately causes a deterioration in the cutting performance of the grinding wheel and it
is therefore usual for the surface of the grinding wheel to be periodially dressed by a diamond dresser. Such a diamond dresser can either by constituted by a single diamond tip dresser, or by a
rotary dresser which has a large number of diamonds or other abrasive grains buried in its surface.
In the case of a single diamond tip dresser, the dresser can be operated only when the grinding wheel has finished the grinding of the workpiece, and when the table on which the grinding wheel is mounted has been withdrawn from the workpiece.
Furthermore, after the dresser has effected dressing by being traversed over the circumference of the grinding wheel, it then has to be moved away from the grinding wheel. Moreover, the abrasive grains which are arranged irregularly at the periphery of the grinding wheel strike against the end of the single diamond tip dresser with the result that irregular vibration of the grinding wheel can be easily caused such that it is not possible to grind the workpiece to the desired degree of accuracy. It is therefore necessary to effect dressing of the grinding wheel by a large number of traverses of the single diamond tip dresser and this means that the dressing is a lengthy operation.Furthermore, as a result of the said irregular vibration during the dressing, cracks can be produced both in the said abrasive grains themselves and in the material which is used to cement these abrasive grains into the circumference of the grinding wheel. If this occurs, there can be abrasion of the grinding wheel at the beginning of the grinding operation and this can produce a change in the shape of the grinding wheel. Consequently it is desirable not to have to effect dressing in this way if one wishes to attain high precision.
If, on the other hand, the diamond dresser is constituted by a rotary dresser, dressing is effected by feeding the rotary dresser against the periphery of the grinding wheel. In this case dressing is effected more swiftly than by the use of a single diamond tip dresser. However, the cutting points of the abrasive grains in the grinding wheel become abraded by the rotary dresser so that the power required for grinding has to be increased and the quality of the grinding is therefore reduced.
A rotary dresser is often used in cases where the products do not need to be ground with high precision, but the actual actofgrinding tends to cause the abrasive grains in the grinding wheel to fall out and tends to destroy the material which cements these abrasive grains into the grinding wheel.
According, therefore, to the present invention, there is provided a grinding machine comprising a
grinding wheel; means for rotating the grinding
wheel; a dressing wheel; means for rotating the
dressing wheel; means for maintaining the grinding wheel and the dressing wheel in a dressing position
in which in operation the dressing wheel dresses the grinding wheel; a dressing device; and means for
maintaining the dressing wheel and the dressing device in a dressing position in which in operation the dressing device dresses the dressing wheel.
Preferably, the means for maintaining the grinding wheel and the dressing wheel in a dressing position are operable to effect relative movement between the grinding wheel and the dressing wheel into and out of this dressing position.
Preferably also the means for maintaining the dressing wheel and the dressing device in a dressing position are operable to effect relative movement between the dressing wheel and the dressing device into and out of the last-mentioned dressing position.
The construction is preferably such that the dressing device can dress the dressing wheel at the same time as the grinding wheel is grinding a workpiece.
The hardness of abrasive material in the dressing wheel may be substantially the same as that of abrasive material in the grinding wheel.
In one embodiment, the dressing device comprises a second dressing wheel which is arranged to be driven at a different circumferential speed than that of the first-mentioned dressing wheel. In this case, the hardness of abrasive material in the second dressing wheel may be substantially the same as that of abrasive material in the first-mentioned dressing wheel. Preferably, the maximum diameter of the second dressing wheel differs from that of the first-mentioned dressing wheel.
In another embodiment, the dressing device comprises a non-rotatable abrasive member such as a single non-rotatable diamond tip.
The grinding machine preferably comprises a workpiece support means, and means for effecting relative movement between the grinding wheel and the workpiece support means to enable a workpiece carried by the workpiece support means to be ground by the grinding wheel.
The invention also comprises a method of grinding a workpiece comprising employing a rotating grinding wheel to effect such grinding, dressing the grinding wheel by means of a dressing wheel, and dressing the dressing wheel by means of a dressing device. The method may comprise advancing the grinding wheel into contact with the workpiece, withdrawing the grinding wheel from the workpiece after it has ground the latter, advancing the dressing wheel into contact with the grinding wheel and dressing the latter, withdrawing the dressing wheel from the grinding wheel, advancing the dressing device into contact with the dressing wheel which has been so withdrawn, and employing the dressing device to dress the dressing wheel.
In the case of the present invention, therefore, the grinding wheel can be dressed in a shorter time than is possible by the use of a single diamond tip dresser and, if a second dressing wheel is employed whose abrasive material has substantially the same hardness as that of the first-mentioned dressing wheel, then less damage will be done to the grinding wheel by the dressing operation than would normally occur. The invention thus enables dressing of the grinding wheel to be effected in such a way as to maintain high precision grinding with the grinding wheel exercising good cutting power.
The invention is illustrated, merely by way of example, in the accompanying drawings, in which:
Figure 1 is a plan view of an internal grinding machine according to the present invention,
Figure 2 is a side view of part of the structure shown in Figure 1,
Figure 3 is a plan view of an external grinding machine according to the present invention, and
Figure 4 is a side view of the external grinding machine shown in Figure 3.
Terms such as "left" and "right" as used in the description below, are to be understood to refer to the directions as seen in the accompanying drawings.
In Figures 1 and 2 there is shown an internal grinding machine according to the present invention comprising a main table 1 on which there is slidably mounted a grinding wheel table 2. The grinding wheel table 2 is mounted for reciprocation by a piston and cylinder device (not shown) towards and away from a workpiece support or cutting table 3.
Rotatably mounted on the grinding wheel table 2 is a rotary grinding shaft 4 which supports a grinding wheel 6 and which is driven by a motor M1.
Rotatably mounted on the cutting table 3 is a shaft 5 having means for supporting a workpiece W, the shafts 4, 5 being co-axial. The grinding wheel 6 and the workpiece W are supported at the respective ends of the shafts 4, 5.
The grinding wheel table 2 can be advanced towards the left from a dressing position in which it is shown in Figure 1 to a grinding position (not shown) in which the grinding wheel 6 is disposed internally of the workpiece W. After the internal grinding of the workpiece W has been completed, the grinding wheel 6 can be moved back towards the right into the dressing position shown in Figure 1.
The cutting table 3 can be reciprocated by a servomotor and a feed screw (not shown) in a direction at right angles to the direction in which the grinding wheel 6 can be moved by its piston and cylinder device. Thus by appropriate movement of the grinding wheel 6 and of the workpiece W, the required internal grinding of the workpiece W may be effected.
A dressing wheel table 8 is also slidably mounted on the main table 1 and is movable towards and away from the grinding wheel table 2 and thus towards and away from the grinding wheel 6 by means of a motor M2 and a lead screw 7. The dressing wheel table 8 carries a shaft 9 on which there is mounted a dressing wheel 10, the dressing wheel 10 being rotatable by a motor M3 which is mounted on the dressing wheel table 8.
The motor M2 and the lead screw 7 can thus effect relative movement between the grinding wheel 6 and the dressing wheel 10 into and out of a dressing position in which in operation the dressing wheel 10 dresses the grinding wheel 6.
A U-shaped frame 11 is mounted on the spindle 9.
The U-shaped frame 11 supports a dressing device 13 which can be raised and lowered within the frame 11 by means comprising a motor M4 and a lead screw 12. The dressing device 13 comprises a rotary diamond dresser or second dressing wheel 16. Thus the motor M4 and the lead screw 12 are operable to effect relative movement between the dressing wheel 10 and the second dressing wheel 16 into and out of a dressing position shown in Figure 2 in which in operation the second dressing wheel 16 dresses the dressing wheel 10. Dressing of the dressing wheel 10 by the dressing device 13 can be effected when the latter is in its lowermost position in the frame 11.
The dressing device 13, which can be moved longitudinally of the frame 11, comprises a spindle frame 14 which is movable by the lead screw 12. The second dressing wheel 16 is mounted at the end of a spindle 15. The spindle 15 is rotatably mounted in the spindle frame 14 and may be driven by a motor M5 which is mounted on one portion of the spindle frame 14. Thus the second dressing wheel 16 can be moved up and down with respect to the dressing wheel 10.
In operation, the grinding wheel table 2 is moved by the piston and cylinder device towards the left so as to introduce the grinding wheel 6 into the interior of the workpiece W and the latter is moved, during rotation of the grinding wheel 6, in a direction at right angles to the axis of the grinding wheel 6 so that the internal grinding of the workpiece W is effected. The grinding wheel 6 is then withdrawn towards the right away from the workpiece W after it has ground the latter, and the dressing wheel table 8 is then advanced by its motor M2 and lead screw 7 so that the dressing wheel 10 is advanced into dressing contact with the grinding wheel 6 and dresses the latter.As clearly shown in Figures 1 and 2, the maximum diameter of the dressing wheel 10 is substantially greaterthanthat of the grinding wheel 6 so that if the shafts 4,9 are rotated at the same angular speed, there will be a difference in the circumferential speed of the dressing wheel 10 and grinding wheel 6 whereby the latter will be dressed.
After the grinding wheel 6 has been so dressed, the motor M2 and lead screw 7 are driven so as to withdraw the dressing wheel 10 from the grinding wheel 6. The second dressing wheel 16 is then moved downwardly by its motor M4 and lead screw 12 into contact with the dressing wheel 10 which has been so withdrawn from the grinding wheel 6, and the rotation of the second dressing wheel 16 by the motor M4 will then effect dressing of the dressing wheel 10. If desired, this dressing of the dressing wheel 10 by the second dressing wheel 16 may be effected simultaneously with the grinding of a further workpiece W by the grinding wheel 6.
Since the maximum diameter of the second dressing wheel 16 is substantially less than that of the dressing wheel 10, if the shafts 9, 15 are rotated by their respective motors at the same angular speed, there will be a difference in the circumferen tial speeds of the second dressing wheel 16 and of the dressing wheel 10 so as to effect the required dressing of the latter.
The dressing wheel 10 may have abrasive grains in its circumference which are cemented thereto by connecting material and the grinding wheel 6 and the second dressing wheel 16 may be similarly formed. The dressing wheel 10 is of course subjected to abrasion as a result of the dressing of the grinding wheel 6 but by reason of the fact that there is little difference in hardness between the abrasive material in the second dressing wheel 16 and in the dressing wheel 10, the dressing of the latter involves substantially little further abrasion. Moreover, if the hardness of the abrasive material in the dressing wheel 10 is substantiallythe same as that of the abrasive material in the grinding wheel 6, then abrasion of the grinding wheel 6 by the dressing wheel 10 will be similarly reduced.
The dressing wheel 10 may be made by a wide variety of methods and of a wide variety of materials. Thus there can be considerable variation in the quality and hardness of the abrasive grains employed, of their particle sizes, and of the material used for cementing the abrasive grains into the dressing wheel 10. By comparison with the use of the prior art single diamond tip dresser, the dressing of the grinding wheel 6 by the dressing wheel 10 reduces the time taken for dressing. Because, moreover, this dressing is done by means of abrasive grains whose hardness does not differ very much from those of the grinding wheel 6, little damage is done to the latter by the dressing and any initial abrasion which will occur between the grinding wheel 10 and the workpiece W is therefore reduced.The construction described above is thus very suitable for restoring the grinding wheel 6 to a fully efficient state after it has been used.
Moreover, there will be ample time to effect dressing of the dressing wheel 10 during the time that is taken for the grinding wheel 6 to effect grinding of a workpiece.
In Figures 3 and 4 there is shown a grinding machine for grinding the exterior of a workpiece W.
The grinding machine of Figures 3 and 4 comprises a grinding wheel table 22 which is mounted for sliding movement with respect to a base 22a by a feed machanism which comprises a drive motor M12 and a lead screw 21. The grinding wheel table 22 carries a grinding wheel spindle 23 at one end of which there is mounted a grinding wheel 24 for grinding the exterior surface of a workpiece W which is supported by a work spindle 20. The motor M12 may be driven so as to advance the grinding wheel 24 into grinding contact with the workpiece W and to withdraw itthereform at the end of the grinding operation. The grinding wheel spindle 23 is driven by a motor M15 mounted on the grinding wheel table 22.
A dressing wheel table 26 is slidably mounted on the grinding wheel table 22. The dressing wheel table 26 is movable towards and away from the grinding wheel 24 by a motor M13 and a lead screw 25. A dressing wheel 28 is mounted at one end of a dressing wheel spindle 27 which is driven by a motor M14, the dressing wheel spindle 27 being carried by the dressing wheel table 26.
A cutting table 30 is mounted for sliding movement towards and away from the dressing wheel 28, the cutting table 30 being so movable by a cutting feeding motor M 10. The cutting table 30 is supported by a frame 29 which is itself slidably mounted on the dressing wheel table 26 opposite to the dressing wheel 28. A non-rotatable dresser 31, which forms part of a dressing device 33, is provided with a single diamond tip or other abrasive member 32 which is mounted opposite to the dressing wheel 28 and can be moved backwards and forwards into and out of dressing contact with the latter. Traversing movement of the dresser 31 with respect to the dressing wheel 28 may be effected by operation of a motor
M11.
In operation, a workpiece W whose exterior is to be ground is mounted on the spindle 20 and the motor M12 is actuated so as to bring the grinding wheel 24 into grinding contact with the circumference of the workpiece W. The grinding wheel 24 is then rotated by the motor M15 until grinding has been completed. The motor M12 is then actuated so as to remove the grinding wheel 24 from the workpiece W and the grinding wheel 24 is then dressed by employing the motor M12 to bring the dressing wheel 28 into contact with the grinding wheel 24. Rotation of the grinding wheel 24 by its motor M15 and rotation of the dressing wheel 28 by its motor M14 may be arranged to produce similar angular speeds of the spindles 23,27 and will thus produce different circumferential speeds of the grinding wheel 24 and dressing wheel 28 by reason of their different diameters.The dressing wheel 28 will consequently effect dressing of the grinding wheel 24. The dressing wheel 28 is then moved towards the right by its motor M13 to a position in which it is no longer in contact with the grinding wheel 24 and the dresser 31 is then moved by its motor M10 so as to bring the diamond tip 32 into dressing contact with the circumference of the dressing wheel 28. The dressing wheel 28 is then dressed by traversing the diamond tip 32 over the circumference of the dressing wheel 28, such traversing being effected by means of the motor Mali. A number of such traverses are effected in order to dress the dressing wheel 28.
As in the construction of Figures 1 and 2, in the grinding machine of Figures 3 and 4, the time taken for dressing is substantially less than when a conventional single diamond dresser is used, while ensuring that the workpiece can be ground with high accuracy.
Claims (17)
1. A grinding machine comprising a grinding wheel; means for rotating the grinding wheel; a dressing wheel; means for rotating the dressing wheel; means for maintaining the grinding wheel and the dressing wheel in a dressing position in which in operation the dressing wheel dresses the grinding wheel; a dressing device; and means for maintaining the dressing wheel and the dressing device in a dressing position in which in operation the dressing device dresses the dressing wheel.
2. A grinding machine as claimed in claim 1 in which the means for maintaining the grinding wheel and the dressing wheel in a dressing position are operable to effect relative movement between the grinding wheel and the dressing wheel into and out of this dressing position.
3. A grinding machine as claimed in claim 1 or 2 in which the means for maintaining the dressing wheel and the dressing device in a dressing position are operable to effect relative movement between the dressing wheel and the dressing device into and out of the last-mentioned dressing position.
4. A grinding machine as claimed in any preceding claim in which the construction is such that the dressing device can dress the dressing wheel at the same time as the grinding wheel is grinding a workpiece.
5. A grinding machine as claimed in any preceding claim in which the hardness of abrasive material in the dressing wheel is substantially the same as that of abrasive material in the grinding wheel.
6. A grinding machine as claimed in any preceding claim in which the dressing device comprises a second dressing wheel which is arranged to be driven at a different circumferential speed than that of the first-mentioned dressing wheel.
7. A grinding machine as claimed in claim 6 in which the hardness of abrasive material in the second dressing wheel is substantially the same as that of abrasive material in the first-mentioned dressing wheel.
8. A grinding machine as claimed in claim 6 or 7 in which the maximum diameter of the second dressing wheel differs from that of the firstmentioned dressing wheel.
9. A grinding machine as claimed in any of claims 1 to 5 in which the dressing device comprises a non-rotatable abrasive member.
10. A grinding machine as claimed in claim 9 in which the dressing device comprises a single nonrotable diamond tip.
11. A grinding machine as claimed in any preceding claim comprising a workpiece support means, and means for effecting relative movement between the grinding wheel and the workpiece support means to enable a workpiece carried by the workpiece support means to be ground by the grinding wheel.
12. A grinding machine substantially as hereinbefore described with reference to and as shown in
Figure 1 and 2 or in Figures 3 and 4 of the accompanying drawings.
13. A method of grinding a workpiece comprising employing a rotating grinding wheel to effect such grinding, dressing the grinding wheel by means of a dressing wheel, and dressing the dressing wheel by means of a dressing device.
14. A method as claimed in claim 13 in which the dressing of the dressing wheel by the dressing device is effected simultaneously with the grinding of the workpiece by the grinding wheel.
15. A method as claimed in claim 13 or 14 comprising advancing the grinding wheel into contact with the workpiece, withdrawing the grinding wheel from the workpiece after it has ground the latter, advancing the dressing wheel into contact with the grinding wheel and dressing the latter, withdrawing the dressing wheel from the grinding wheel, advancing the dressing device into contact with the dressing wheel which has been so withdrawn, and employing the dressing device to dress the dressing wheel.
16. A method of grinding a workpiece substantially as hereinbefore described with reference to
Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.
17. A grinding machine having a dressing device which comprises in combination: a feed table which is movable with respect to the grinding member, a rotary dressing member which is rotatably driven and is mounted on said feed table and dresses said grinding member, a second feed table which is movable with respect to said dressing member; and a second dressing device which is for dressing said dressing member.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3494982A JPS58155170A (en) | 1982-03-05 | 1982-03-05 | Grinder equipped with dressing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8305795D0 GB8305795D0 (en) | 1983-04-07 |
| GB2116085A true GB2116085A (en) | 1983-09-21 |
Family
ID=12428411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08305795A Withdrawn GB2116085A (en) | 1982-03-05 | 1983-03-02 | Grinding machine and method of grinding a workpiece |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS58155170A (en) |
| DE (1) | DE3307599A1 (en) |
| GB (1) | GB2116085A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5441449A (en) * | 1994-06-16 | 1995-08-15 | Hart; Glen B. | Integratable grinding wheel dresser |
| US6024632A (en) * | 1996-09-26 | 2000-02-15 | Aisin Seiki Kabushiki Kaisha | Grinding method using grit stuck to a tool having low hardness |
| CN101326032B (en) * | 2005-12-14 | 2011-11-16 | Osg株式会社 | Cervix grinding apparatus and grinding device used by the cervix grinding apparatus and cervix grinding method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62199360A (en) * | 1986-02-21 | 1987-09-03 | Okuma Mach Works Ltd | Numerically controlled grinding machine having correcting tool for truing tool |
| JP4441823B2 (en) * | 2003-11-26 | 2010-03-31 | 株式会社東京精密 | Truing method and chamfering device for chamfering grindstone |
-
1982
- 1982-03-05 JP JP3494982A patent/JPS58155170A/en active Pending
-
1983
- 1983-03-02 GB GB08305795A patent/GB2116085A/en not_active Withdrawn
- 1983-03-03 DE DE19833307599 patent/DE3307599A1/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5441449A (en) * | 1994-06-16 | 1995-08-15 | Hart; Glen B. | Integratable grinding wheel dresser |
| US6024632A (en) * | 1996-09-26 | 2000-02-15 | Aisin Seiki Kabushiki Kaisha | Grinding method using grit stuck to a tool having low hardness |
| CN101326032B (en) * | 2005-12-14 | 2011-11-16 | Osg株式会社 | Cervix grinding apparatus and grinding device used by the cervix grinding apparatus and cervix grinding method |
| US8257144B2 (en) | 2005-12-14 | 2012-09-04 | Osg Corporation | Neck portion grinding apparatus and grinding device employed in the neck portion grinding apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3307599A1 (en) | 1983-09-22 |
| GB8305795D0 (en) | 1983-04-07 |
| JPS58155170A (en) | 1983-09-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |