CA1324492C - Composite grinding wheel - Google Patents
Composite grinding wheelInfo
- Publication number
- CA1324492C CA1324492C CA000531338A CA531338A CA1324492C CA 1324492 C CA1324492 C CA 1324492C CA 000531338 A CA000531338 A CA 000531338A CA 531338 A CA531338 A CA 531338A CA 1324492 C CA1324492 C CA 1324492C
- Authority
- CA
- Canada
- Prior art keywords
- core
- abrasive
- grinding wheel
- rim
- aluminum
- 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 - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/02—Wheels in one piece
- B24D7/04—Wheels in one piece with reinforcing means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
- B24D5/02—Wheels in one piece
- B24D5/04—Wheels in one piece with reinforcing means
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Polishing Bodies And Polishing Tools (AREA)
Abstract
ABSTRACT
A composite grinding wheel having an abrasive rim containing super abrasive grits, an active halide filler, and particulate silver, mounted on an aluminum powder filled polymer core is improved as to electrolytic degradation between the rim and the core by substituting copper or some other non-aluminum filler for the aluminum in the core immediately adjacent the grinding section of the wheel.
A composite grinding wheel having an abrasive rim containing super abrasive grits, an active halide filler, and particulate silver, mounted on an aluminum powder filled polymer core is improved as to electrolytic degradation between the rim and the core by substituting copper or some other non-aluminum filler for the aluminum in the core immediately adjacent the grinding section of the wheel.
Description
132~92 COMROSIlE GRINDI~G hHE~L
RICHARD H. SIO~I
lB Avery Heights Drive Holàen, Massachusetts 01520 FIELD OF THE INVENTION
The in~ention relates to grinding wheels havins a non-abrasive core supporting an abrasive containing rim, in particular, a super abr~sive material in which the rim 5 abrasive section contains active filler material and silver powder.
B~CKGROU~D OF THE INVENTION
Diamond grit or CBN grit containing grinding whePls are customarily made with an abrasive rim section and 10 a supportin~ core. Because of the need for strength and thermal conductivity, the core is desireably an organic polymer filled with a metal powder. Aluminum is a particularly desireable filler metal for the core because of :
its relatively low density, high conducti~ity, and low co~t.
U.S. Patent 3,863,233 teaches that such cores may employ aluminum, copper, or a mixture of aluminum and copper as a filler. In addition, graphite has been employed to facilitate dressing away of the core material near the abr~sive rim in cup-type wheels. Such wheels may employ the ~0 graphite additive only in the portion of the core adjacent `
to the abrasive rim. ` `
With the advent of the use of cubic boron nitride abrasive grits, the use of active fillers in the abrasive rim section became commercially used to improve the grinding 25 of ferrous and other metals. Such fillers, which improve `
the grindability of the metal workpiece may also be used in cases where diamond is the abrasive, or where a blend of diamond and CBN is used. Secondary, non premiumJ abrasives may also be used. The diamond and CB~ are preferably metal 30 clad. Nickel is a common cladding. ~
~
`- - ` 1324~92 -For optimum performance in the grinding of tool steels, the incl~sion of s~lver pow~er in the abrasive section, tooether with the active fill~r has been found particu'arly advantageous. ~To reduce the power consumption 5 it is also desire3ble to include a dry film lubricant filler in the abrasive rim. Such fillers include ~eflon* graphite, hexagonal boron nitride, and molybàenum disulphiàe. British published Application 2136011-A corresponding to West German Application 3404851-A, published July 16, 1984, àiscloses 10 resin bonded ~rinding wheel rims containing CB~, active filler, dry film lubricant, and silver powder.
Although such wheels, when the rim is mounted on the core containing aluminum powder as a filler, have shown high efficiency in the grinding of difficult-to-grind tool 15 steels, they have suffered from ins~ability when stored in a humid atmcsphere, In such wheels the damage occurs at the interface between the abrasive rim and the aluminum bearing core, and in severe cases causes the rim to crumble apart.
DESCRIPTION O~ THE INVENTION
~0 Further investigation of the degradation effect in a humid atmosphere led to the discovery that the problem was caused by an electrolytic action between t~e aluminum in the core ~nd the silver in the rim, in the presence of electrolytes such as the halogen salts used as active 25 fillers. In accordance with the ~nown standard oxidation reduction potentials of silver salts and aluminum it is postulated that silver ions (Ag+) from the æurface of the si}ver particles migrate toward the core section due to the electrolytic effect of the couple between Ag+ and aluminum 30 metal. Since removal of the silver from the rim would reduce the grinding efficiency of the abrasive, and substitution of some other metal for aluminum would increase the cost, density, (resulting in balance problems) and/or thermal conductivity of the core, -he solution to the 35 problem was not apparent.
The effective solution, the subject of this invention, was found to be a substitution of copper for the - . . .
*Trademar~
- " .
13244~2 ~luminum in the core 2t those portions of the core immediately aàjacent the abrasive containins section, while retaining aluminum filler in the major portion of the core.
5 BRIEF DESCRIP~10~ OF THE DRAh'lN~
In the drawing, Figure 1 shows a straight wheel with a composite core 10 of aluminum filled resin, with a non-aluminum section 11 adjacent to the abrasive rim 12, an~
a mounting hole 13.
~igure 2 shows a cup-type wheel with an aluminum filled ~orë 20, a non-aluminum filled portion 21, an abrasive rim 22, and a mounting hole 23.
DETAILED DESCRIPTION O~ THE INVENTION
In the manufacture of cup-type wheels which were 15 tested for reaction to a humid environment, reported below, first the core was formed in a mold oriented such that the portion cup shaped core which will be ad3acent to the CBN
section is in the bottom. Sufficient copper filled resin powder to build the section 21 in Figure 2 is placed in the 20 mold, hand packed, and leveled, The aluminum powder containing resin is then placed on top, packed and leveled, The entire assembly is then pressed and the core removed ` `
from the mold. The lower portion of the core is then shaped on a lathe to provide a recess into which the drive rim 25 section fits in a subsequent molding operation, Various methods of constructing a composite wheel of this type, and various core compositions containing aluminum powder are discussed in U.S. Patent 3,868,233.
Typical molding conditions are 5 tons per sgure inch pressure, a temperature of 160C, and a molding time of 20 minutes. The final cure can be carried out in an air atmosphere oven for 24 hours at 175C. As is known in the art, the time and temperature of cure is varied to control 35 the grade of harndess of the wheel depending upon the specific application.
'A, .
24~2 A~rasi~e rimC were fa~ricateà containing CB~
(cubic boron nitride~ a~rasive grits, nickel clad, 25% ~y volume (based on the CB~ volume), and mounted on cores of different composition. A sui~able formulation for the bond and fillers for the rim is as follows:
Material Volume KAlF4 active filler (powder) 25 Silver powder 20 MoS2 po~der ~dry film lubricant) 10 Phenolic resin (novolac powder containing 2 vol ~ Cao based on total bond volume) 45 The mix for the ri~ sections was prepared by wetting the CBN abrasive grit material with furfural and 15 blending it with the mixture of bond and fillers. The mix was cold pressed to a shape in the recess in the cup, and the whole assembly cured by beat.
Nheels, for test purposes, were made having unitary aluminum filled cores, and some having composite 20 cores, as in Figures 1 and 2. Wheels havinq composi~e cores, in which the section adjacent the rim contained copper or no metallic filler survived a period of 8 days exposure to hot humid air (85 to 90S relative humidity at 120C), while the wheel with all-a}uminum filled cores, 25 suffered catastrophic degradation of the rim sections.
Other metals than copper, having a lower EMF
difference than that between aluminum and silver may be used, such as nickel, iron, or cobalt. Copper is preferred :-as less active and of higher thermal conductivity. The core 30 material may also contain graphite and other fillers. A
suitable core composition is taught in U.S. Patent 3,868,233.
.. ...
RICHARD H. SIO~I
lB Avery Heights Drive Holàen, Massachusetts 01520 FIELD OF THE INVENTION
The in~ention relates to grinding wheels havins a non-abrasive core supporting an abrasive containing rim, in particular, a super abr~sive material in which the rim 5 abrasive section contains active filler material and silver powder.
B~CKGROU~D OF THE INVENTION
Diamond grit or CBN grit containing grinding whePls are customarily made with an abrasive rim section and 10 a supportin~ core. Because of the need for strength and thermal conductivity, the core is desireably an organic polymer filled with a metal powder. Aluminum is a particularly desireable filler metal for the core because of :
its relatively low density, high conducti~ity, and low co~t.
U.S. Patent 3,863,233 teaches that such cores may employ aluminum, copper, or a mixture of aluminum and copper as a filler. In addition, graphite has been employed to facilitate dressing away of the core material near the abr~sive rim in cup-type wheels. Such wheels may employ the ~0 graphite additive only in the portion of the core adjacent `
to the abrasive rim. ` `
With the advent of the use of cubic boron nitride abrasive grits, the use of active fillers in the abrasive rim section became commercially used to improve the grinding 25 of ferrous and other metals. Such fillers, which improve `
the grindability of the metal workpiece may also be used in cases where diamond is the abrasive, or where a blend of diamond and CBN is used. Secondary, non premiumJ abrasives may also be used. The diamond and CB~ are preferably metal 30 clad. Nickel is a common cladding. ~
~
`- - ` 1324~92 -For optimum performance in the grinding of tool steels, the incl~sion of s~lver pow~er in the abrasive section, tooether with the active fill~r has been found particu'arly advantageous. ~To reduce the power consumption 5 it is also desire3ble to include a dry film lubricant filler in the abrasive rim. Such fillers include ~eflon* graphite, hexagonal boron nitride, and molybàenum disulphiàe. British published Application 2136011-A corresponding to West German Application 3404851-A, published July 16, 1984, àiscloses 10 resin bonded ~rinding wheel rims containing CB~, active filler, dry film lubricant, and silver powder.
Although such wheels, when the rim is mounted on the core containing aluminum powder as a filler, have shown high efficiency in the grinding of difficult-to-grind tool 15 steels, they have suffered from ins~ability when stored in a humid atmcsphere, In such wheels the damage occurs at the interface between the abrasive rim and the aluminum bearing core, and in severe cases causes the rim to crumble apart.
DESCRIPTION O~ THE INVENTION
~0 Further investigation of the degradation effect in a humid atmosphere led to the discovery that the problem was caused by an electrolytic action between t~e aluminum in the core ~nd the silver in the rim, in the presence of electrolytes such as the halogen salts used as active 25 fillers. In accordance with the ~nown standard oxidation reduction potentials of silver salts and aluminum it is postulated that silver ions (Ag+) from the æurface of the si}ver particles migrate toward the core section due to the electrolytic effect of the couple between Ag+ and aluminum 30 metal. Since removal of the silver from the rim would reduce the grinding efficiency of the abrasive, and substitution of some other metal for aluminum would increase the cost, density, (resulting in balance problems) and/or thermal conductivity of the core, -he solution to the 35 problem was not apparent.
The effective solution, the subject of this invention, was found to be a substitution of copper for the - . . .
*Trademar~
- " .
13244~2 ~luminum in the core 2t those portions of the core immediately aàjacent the abrasive containins section, while retaining aluminum filler in the major portion of the core.
5 BRIEF DESCRIP~10~ OF THE DRAh'lN~
In the drawing, Figure 1 shows a straight wheel with a composite core 10 of aluminum filled resin, with a non-aluminum section 11 adjacent to the abrasive rim 12, an~
a mounting hole 13.
~igure 2 shows a cup-type wheel with an aluminum filled ~orë 20, a non-aluminum filled portion 21, an abrasive rim 22, and a mounting hole 23.
DETAILED DESCRIPTION O~ THE INVENTION
In the manufacture of cup-type wheels which were 15 tested for reaction to a humid environment, reported below, first the core was formed in a mold oriented such that the portion cup shaped core which will be ad3acent to the CBN
section is in the bottom. Sufficient copper filled resin powder to build the section 21 in Figure 2 is placed in the 20 mold, hand packed, and leveled, The aluminum powder containing resin is then placed on top, packed and leveled, The entire assembly is then pressed and the core removed ` `
from the mold. The lower portion of the core is then shaped on a lathe to provide a recess into which the drive rim 25 section fits in a subsequent molding operation, Various methods of constructing a composite wheel of this type, and various core compositions containing aluminum powder are discussed in U.S. Patent 3,868,233.
Typical molding conditions are 5 tons per sgure inch pressure, a temperature of 160C, and a molding time of 20 minutes. The final cure can be carried out in an air atmosphere oven for 24 hours at 175C. As is known in the art, the time and temperature of cure is varied to control 35 the grade of harndess of the wheel depending upon the specific application.
'A, .
24~2 A~rasi~e rimC were fa~ricateà containing CB~
(cubic boron nitride~ a~rasive grits, nickel clad, 25% ~y volume (based on the CB~ volume), and mounted on cores of different composition. A sui~able formulation for the bond and fillers for the rim is as follows:
Material Volume KAlF4 active filler (powder) 25 Silver powder 20 MoS2 po~der ~dry film lubricant) 10 Phenolic resin (novolac powder containing 2 vol ~ Cao based on total bond volume) 45 The mix for the ri~ sections was prepared by wetting the CBN abrasive grit material with furfural and 15 blending it with the mixture of bond and fillers. The mix was cold pressed to a shape in the recess in the cup, and the whole assembly cured by beat.
Nheels, for test purposes, were made having unitary aluminum filled cores, and some having composite 20 cores, as in Figures 1 and 2. Wheels havinq composi~e cores, in which the section adjacent the rim contained copper or no metallic filler survived a period of 8 days exposure to hot humid air (85 to 90S relative humidity at 120C), while the wheel with all-a}uminum filled cores, 25 suffered catastrophic degradation of the rim sections.
Other metals than copper, having a lower EMF
difference than that between aluminum and silver may be used, such as nickel, iron, or cobalt. Copper is preferred :-as less active and of higher thermal conductivity. The core 30 material may also contain graphite and other fillers. A
suitable core composition is taught in U.S. Patent 3,868,233.
.. ...
Claims (9)
1. A grinding wheel having a core section and an abrasive-containing rim portion, the major portion of the core section being a resin polymer with an aluminum powder filler, a minor portion of the core adjacent the abrasive-containing rim portion being a resin polymer being free of aluminum powder filler, and the abrasive-containing portion including silver powder and an active filler, whereby significant electrolytic action between the aluminum-containing portion of the core and the abrasive-containing rim is blocked by a copper-containing core portion.
2. A grinding wheel as in claim 1 in which the active filler is a halide salt.
3. A grinding wheel as in claim 2 in which the abrasive is nickel clad and selected from the group consisting of cubic boron nitride and diamond.
4. A grinding wheel as in claim 3 in the form of a cup-wheel
5. A grinding wheel as in claim 1 in which the portion of the core adjacent the rim contains copper powder filler.
6. A grinding wheel having a core section and an abrasive-containing rim portion, the major portion of the core section being a resin polymer with an aluminum powder filler, a minor portion of the core adjacent the abrasive containing rim portion being a resin polymer containing copper powder filler in place of the aluminum powder filler, and he abrasive-containing rim portion including silver powder and an active filler, whereby significant electrolytic action between the aluminum-containing portion of the core and the abrasive-containing rim is blocked by the copper-containing core portion.
7. A grinding wheel according to claim 6, in which the active filer is a halide salt.
8. A grinding wheel according to either claim 6 or 7, in which the abrasive is cubic boron nitride or diamond and is clad with nickel.
9. A grinding wheel according to any one of the preceding claims 6-8, which is in the form of a cup-wheel.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US84733486A | 1986-04-02 | 1986-04-02 | |
| US847,334 | 1986-04-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324492C true CA1324492C (en) | 1993-11-23 |
Family
ID=25300367
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000531338A Expired - Fee Related CA1324492C (en) | 1986-04-02 | 1987-03-06 | Composite grinding wheel |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0239918B1 (en) |
| JP (1) | JPH0671706B2 (en) |
| BR (1) | BR8701479A (en) |
| CA (1) | CA1324492C (en) |
| DE (1) | DE3783791T2 (en) |
| ZA (1) | ZA871902B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5110321A (en) * | 1990-02-13 | 1992-05-05 | Minnesota Mining And Manufacturing Company | Abrasives containing ammonium fluoride-based grinding aid |
| US5219463A (en) * | 1990-02-13 | 1993-06-15 | Minnesota Mining And Manufacturing Company | Abrasives containing ammonium fluoride-based grinding aid |
| GB201701246D0 (en) | 2017-01-25 | 2017-03-08 | Fives Landis Ltd | Machine tools and methods of operation thereof |
| DE202017004776U1 (en) | 2017-09-13 | 2017-10-10 | Prime Supply Inc. | Improved grinding tool |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3283448A (en) * | 1964-08-14 | 1966-11-08 | Bay State Abrasive Products Co | Organic bonded abrasive article |
| US3592618A (en) * | 1969-03-10 | 1971-07-13 | Avco Corp | Abrasive article having a metal filler and an active filler |
| US3816997A (en) * | 1972-03-20 | 1974-06-18 | Itek Corp | Apparatus for simultaneously performing rough and fine grinding operations |
| US3984214A (en) * | 1973-03-05 | 1976-10-05 | Federal-Mogul Corporation | Metal-coated diamond abrasive article containing metal fillers |
| JPS55120980A (en) * | 1979-03-13 | 1980-09-17 | Toshiba Mach Co Ltd | Grinder for vertical-axis plane grinding |
| JPS5641390A (en) * | 1979-09-12 | 1981-04-18 | Masami Fujii | Anticorrosion method for earth electrode material of galvanized steel pipe |
| JPS5893456U (en) * | 1981-12-18 | 1983-06-24 | 株式会社東芝 | grinding wheel |
-
1987
- 1987-03-06 CA CA000531338A patent/CA1324492C/en not_active Expired - Fee Related
- 1987-03-16 ZA ZA871902A patent/ZA871902B/en unknown
- 1987-03-24 EP EP87104352A patent/EP0239918B1/en not_active Expired - Lifetime
- 1987-03-24 DE DE8787104352T patent/DE3783791T2/en not_active Expired - Fee Related
- 1987-04-01 BR BR8701479A patent/BR8701479A/en unknown
- 1987-04-01 JP JP62077630A patent/JPH0671706B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0239918B1 (en) | 1993-01-27 |
| EP0239918A3 (en) | 1990-03-07 |
| JPS62251079A (en) | 1987-10-31 |
| DE3783791D1 (en) | 1993-03-11 |
| JPH0671706B2 (en) | 1994-09-14 |
| ZA871902B (en) | 1987-11-25 |
| EP0239918A2 (en) | 1987-10-07 |
| BR8701479A (en) | 1988-01-19 |
| DE3783791T2 (en) | 1993-05-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |