US2921419A - Grinding and polishing of glass sheets - Google Patents
Grinding and polishing of glass sheets Download PDFInfo
- Publication number
- US2921419A US2921419A US588004A US58800456A US2921419A US 2921419 A US2921419 A US 2921419A US 588004 A US588004 A US 588004A US 58800456 A US58800456 A US 58800456A US 2921419 A US2921419 A US 2921419A
- Authority
- US
- United States
- Prior art keywords
- polishing
- grains
- glass
- grinding
- rubbing
- 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
Links
- 239000011521 glass Substances 0.000 title description 25
- 238000005498 polishing Methods 0.000 title description 17
- 238000000034 method Methods 0.000 description 12
- 229910010271 silicon carbide Inorganic materials 0.000 description 11
- 239000011230 binding agent Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 239000003082 abrasive agent Substances 0.000 description 6
- 229910001018 Cast iron Inorganic materials 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 238000009499 grossing Methods 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- YSMRWXYRXBRSND-UHFFFAOYSA-N TOTP Chemical compound CC1=CC=CC=C1OP(=O)(OC=1C(=CC=CC=1)C)OC1=CC=CC=C1C YSMRWXYRXBRSND-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000006061 abrasive grain Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 239000010431 corundum Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910001651 emery Inorganic materials 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
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
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/20—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground
- B24B7/22—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain
- B24B7/24—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain for grinding or polishing glass
- B24B7/241—Methods
Definitions
- the invention relates to the grinding and polishing of glass sheets. It is known that the operation of grinding and polishing glass sheets comprises a plurality of successive phases, which consist in abrading the surface of the glass by means of abrasives which become progressively finer and which are in suspension in a liquid. In the final phase, or the polishingproper, generally carried out by means of tools having an operative felt surface which is supplied with a suspension of red iron oxide, or polishing powder, the energy required is relatively high; with equal expenditure of energy, a thickness of glass very much smaller than that which is removed in the preceding phase, known as smoothing, is worn away in this phase of the working operation.
- the type of glass with which this invention is most useful is generally called flat glass in American industry.
- the condition of the surface after smoothing is thus of great importance: it must be such that the thickness of glass to be removed in the subsequent polishing phase is reduced to a minimum.
- the invention is concerned with the working phase preceding the polishing and consists in that while the glass surface is fed with the abrasives usual for this phase, a tool formed by hard grains distributed uniformly in a material serving as a binder is usd as the rubbing tool.
- the working phase preceding the polishing is usually carried out by interposing an abrasive in suspension in water between the glass surface and a tool of homogeneous and hard consistency, generally of cast iron.
- a large number of plastic materials and certain soft metals are capable of being used as binders for providing such a rubbing tool.
- the hard grains incorporated with the binder will have a hardness of the same order as or larger than that of the sand used for working glass, and a size in practice which is smaller than 15011.
- the ratio between the hard grains and the binder plays a very important part. The best results are obtained when the proportion is 8 to 17% by volume of hard grains with respect to the total volume of the rubbing tool. A smaller proportion or the complete absence of hard grains would give a much smaller wear on the glass surface, the consequence of which would be an excessive increase in the duration of the working phase preceding the polishing. A larger proportion would also give a very small degree of wear. With a rubbing tool formed for the major part or exclusively of the hard grain material, there would be caused the formation of the cracked sublayer, the existence of which necessitates an increase in the polishing work.
- the rubbing tool must have a hardness which is decidedly less than that of the cast iron hitherto generally used in the same working phases. In practice, its degree of hardness measured with the Shore A hardness meter at 25 C., after 30 seconds, should be between and 95.
- Example 66 g. of polyvinyl chloride, 34 g. of tricresyl phosphate, 40 g. of Carborundum grains are introduced into a mixer and these substances are thoroughly mixed. The agglomeration is then carried out on the cylinders of a rolling mill heated at C., sheets with a thickness of approximately 3 mm. being then drawn therefrom. A certain number of these sheets are assembled by compression at 70 kg. per cm. at C. in order to form a plate of the desired thickness, and the rubbing tools are cut in this plate. The proportion by volume of Carborundum grains in the plate is 13% and the degree of hardness thereof at 25 C., after 30 seconds, is 86 when measured by the Shore A hardness meter.
- the cast iron rubbing tools are replaced by rubbing tools prepared as in dicated above for working with the three last sludges, of which the coarsest grains have mean diameters smaller than 40, 32 and 251.4 respectively.
- the rubbing tools working with the 33 and 25 i sludges were formed by Carborundum grains of 50a.
- the polishing period has been reduced by half.
- the accompanying drawing shows the coeflicient of wear or abrasion obtained with the rubbing tools consisting of plasticised polyvinyl chloride and Carborundum according to the example indicated above, as a function of the percentage by weight of Carborundum in the rubbing tool, the abrasive employed being a sludge, of which the coarsest grains do not exceed 2511.. It will be seen that for each of these curves, there exists a very clear maximum for a content by weight of Carborundum between 20 and 35%, the coeflicient of wear rapidly becoming insignificant on either side of this maximum, in particular for a zero content of Carborundum, that is to say, for rubbing tools constituted exclusively of plasticised vinyl chloride without Carborundum.
- a method for surfacing glass sheets in order to produce polished glass sheets which includes the step of submitting the glass sheet to a grinding phase preceding the polishing phase and carried out by rubbing means comprising a binder and grains at least as hard as conventional free abrasives which are distributed uniformly in the binder, and introducing conventional free abrasives between the means and the glass. 2.
- a method for surfacing glass sheets in view of obtain'ing polished glass sheets which consists in submitting the glass sheet to a grinding phase preceding the polishing phase and carried out by rubbing means comprising a binder, and grains at least as hard as conventional free abrasives in a proportion of 8 to 17 percent of the total volume of the rubbing means, which are distributed uniformly in the binder, and introducing conventional free abrasives between the means and the glass.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Polishing Bodies And Polishing Tools (AREA)
- Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
Description
Jan. 19, 1960 R. TOUVAY GRINDING AND POLISHING OF GLASS SHEETS Filed May 29, 1956 IN V EN TOR. ROBERT TOUVAY WEIGHT OF CARBORUNDUM IN THE RUBBING TOOL Liam ma ATTORNEY S United States Patent GRINDING AND POLISHING OF GLASS SHEETS Robert Tonvay, Paris, France, assignor to Ste Anonyme dee Manufactures des Glaces et Produits Chimiques de sh-Gobain, Chauny et Cirey, Paris, France Application May 29, 1956, Serial No. "588,004 Claims priority, application France June 3,1955
8 Claims. (Cl. 51-283) The invention relates to the grinding and polishing of glass sheets. It is known that the operation of grinding and polishing glass sheets comprises a plurality of successive phases, which consist in abrading the surface of the glass by means of abrasives which become progressively finer and which are in suspension in a liquid. In the final phase, or the polishingproper, generally carried out by means of tools having an operative felt surface which is supplied with a suspension of red iron oxide, or polishing powder, the energy required is relatively high; with equal expenditure of energy, a thickness of glass very much smaller than that which is removed in the preceding phase, known as smoothing, is worn away in this phase of the working operation. The type of glass with which this invention is most useful is generally called flat glass in American industry.
The condition of the surface after smoothing is thus of great importance: it must be such that the thickness of glass to be removed in the subsequent polishing phase is reduced to a minimum.
The invention is concerned with the working phase preceding the polishing and consists in that while the glass surface is fed with the abrasives usual for this phase, a tool formed by hard grains distributed uniformly in a material serving as a binder is usd as the rubbing tool.
The applicant has observed that, under these conditions, the energy necessary for carrying out the polishing is reduced by considerable proportions.
This result can apparently be explained in the following manner:
The working phase preceding the polishing is usually carried out by interposing an abrasive in suspension in water between the glass surface and a tool of homogeneous and hard consistency, generally of cast iron.
It can be admitted that the movements of the grains carried along beneath the homogeneous and hard tool is a rolling movement. In the course of this movement, each grain digs a series of very small holes by indenting the glass surface, the depth of said holes being a function of the size of the grain. in addition, however, these indentations have the effect of producing a cracked sublayer, of approximately the same thickness, beneath the layer comprising the small holes. The result is that, during the polishing, after the polishers have abraded the external layer where the small holes are localised, they come in contact with the subjacent cracked layer, their action causes a flaking or chipping of this layer and the action must be continued until it disappears, the result of which is the necessity of wearing away a thickness of glass substantially double that which it would be necessary to abrade in order to cause the individual small holes to disappear.
in the process according to the invention, on the other hand, it can be assumed that the abrasive supplied to the glass surface is confined between the hard grains set in the material serving as binder and that, under these conditions, the abrasive is carried along by the tool without rolling. It then traces on the glass scratches of a depth substantially equal to that of the small holes which it causes in the ordinary process, but with this essential difference that as a result of this working method, without impact of the abrasive grains, no subjacent layer is formed.
This provides an explanation for the fact that in the process of the invention, since the polishing operation only has to remove the layer in which the scratches are formed, this operation is considerably reduced with respect to the prior processes.
A large number of plastic materials and certain soft metals are capable of being used as binders for providing such a rubbing tool.
The hard grains incorporated with the binder (Carborundum, emery, corundum, metallic grains, etc.) will have a hardness of the same order as or larger than that of the sand used for working glass, and a size in practice which is smaller than 15011.
The ratio between the hard grains and the binder plays a very important part. The best results are obtained when the proportion is 8 to 17% by volume of hard grains with respect to the total volume of the rubbing tool. A smaller proportion or the complete absence of hard grains would give a much smaller wear on the glass surface, the consequence of which would be an excessive increase in the duration of the working phase preceding the polishing. A larger proportion would also give a very small degree of wear. With a rubbing tool formed for the major part or exclusively of the hard grain material, there would be caused the formation of the cracked sublayer, the existence of which necessitates an increase in the polishing work.
The rubbing tool must have a hardness which is decidedly less than that of the cast iron hitherto generally used in the same working phases. In practice, its degree of hardness measured with the Shore A hardness meter at 25 C., after 30 seconds, should be between and 95.
Example 66 g. of polyvinyl chloride, 34 g. of tricresyl phosphate, 40 g. of Carborundum grains are introduced into a mixer and these substances are thoroughly mixed. The agglomeration is then carried out on the cylinders of a rolling mill heated at C., sheets with a thickness of approximately 3 mm. being then drawn therefrom. A certain number of these sheets are assembled by compression at 70 kg. per cm. at C. in order to form a plate of the desired thickness, and the rubbing tools are cut in this plate. The proportion by volume of Carborundum grains in the plate is 13% and the degree of hardness thereof at 25 C., after 30 seconds, is 86 when measured by the Shore A hardness meter.
:In a grinding apparatus comprising cast iron rubbing tools and using sand sludges as abrasive, the cast iron rubbing tools are replaced by rubbing tools prepared as in dicated above for working with the three last sludges, of which the coarsest grains have mean diameters smaller than 40, 32 and 251.4 respectively. The rubbing tools 7 working with sludges having a grain size of 40;/., were formed with Carborundum grains of a size of 10011.. The rubbing tools working with the 33 and 25 i sludges were formed by Carborundum grains of 50a.
The polishing period has been reduced by half.
The accompanying drawing shows the coeflicient of wear or abrasion obtained with the rubbing tools consisting of plasticised polyvinyl chloride and Carborundum according to the example indicated above, as a function of the percentage by weight of Carborundum in the rubbing tool, the abrasive employed being a sludge, of which the coarsest grains do not exceed 2511.. It will be seen that for each of these curves, there exists a very clear maximum for a content by weight of Carborundum between 20 and 35%, the coeflicient of wear rapidly becoming insignificant on either side of this maximum, in particular for a zero content of Carborundum, that is to say, for rubbing tools constituted exclusively of plasticised vinyl chloride without Carborundum.
What is claimed is:
1'. A method for surfacing glass sheets in order to produce polished glass sheets, which includes the step of submitting the glass sheet to a grinding phase preceding the polishing phase and carried out by rubbing means comprising a binder and grains at least as hard as conventional free abrasives which are distributed uniformly in the binder, and introducing conventional free abrasives between the means and the glass. 2. A method for surfacing glass sheets in view of obtain'ing polished glass sheets, which consists in submitting the glass sheet to a grinding phase preceding the polishing phase and carried out by rubbing means comprising a binder, and grains at least as hard as conventional free abrasives in a proportion of 8 to 17 percent of the total volume of the rubbing means, which are distributed uniformly in the binder, and introducing conventional free abrasives between the means and the glass.
3. The method of claim 2 in which the grains set in the softer material constitute about 8%17% of the total volume of the softer material and the set grains. 4. The method of claim 2 in which the set grains are not over about 150p. in size.
5. The method of claim '2 in which the material comprised of the set grains and softer material has a hardness after 30 sec. at 25' C. of 75-95 on the Shore A meter.
6. The method of claim 1 in which the size of grain in the free abrasive is on the order of 40; and the size of set grains is on the order of loop 7. The method of claim 2 in which the size of grain in the free abrasive is on the order of 33-25;. and that of the set grains is on the order of 50 1,.
References Cited in the file of this patent UNITED STATES PATENTS 387,555 Cummings Aug. 7, 1888 749,551 Goehring et al. Jan. 12, 1904 2,097,730 Mall e i.. Nov. 2, 1937 2,137,329 Boyer Nov. 22, 1938 2,268,869 Given Y Jan. 6, 1942 2,426,215 Hicks Aug. 26, 1947 2,597,182 Rickner -2 May 20, 1952 2,643,494 Erickson June 30, 1953 Harvey Aug. 28, 1956
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR2921419X | 1955-06-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2921419A true US2921419A (en) | 1960-01-19 |
Family
ID=9689966
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US588004A Expired - Lifetime US2921419A (en) | 1955-06-03 | 1956-05-29 | Grinding and polishing of glass sheets |
Country Status (1)
Country | Link |
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US (1) | US2921419A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3177628A (en) * | 1961-06-26 | 1965-04-13 | Engelhard Hanovia Inc | Grinding of materials with hard abrasives |
US3236009A (en) * | 1961-06-26 | 1966-02-22 | Engelhard Hanovia Inc | Apparatus for surfacing |
US3662501A (en) * | 1971-01-28 | 1972-05-16 | Ibm | Method for polishing magnetic oxide materials |
US3662500A (en) * | 1971-01-28 | 1972-05-16 | Ibm | Method for polishing magnetic oxide materials |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US387555A (en) * | 1888-08-07 | cumminas | ||
US749551A (en) * | 1904-01-12 | goehring | ||
US2097730A (en) * | 1935-04-12 | 1937-11-02 | Mall Arthur William | Terrazzo grinding apparatus |
US2137329A (en) * | 1937-05-11 | 1938-11-22 | Carborundum Co | Abrasive article and its manufacture |
US2268869A (en) * | 1941-06-28 | 1942-01-06 | Perfect Circle Co | Bearing member |
US2426215A (en) * | 1944-11-11 | 1947-08-26 | Eastman Kodak Co | Thermoplastic synthetic resin optical lap |
US2597182A (en) * | 1949-03-31 | 1952-05-20 | Libbey Owens Ford Glass Co | Surfacing glass sheets or plates |
US2643494A (en) * | 1952-08-25 | 1953-06-30 | Norton Co | Grinding wheel |
US2760313A (en) * | 1955-05-12 | 1956-08-28 | American Viscose Corp | Abrasive wheel |
-
1956
- 1956-05-29 US US588004A patent/US2921419A/en not_active Expired - Lifetime
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US387555A (en) * | 1888-08-07 | cumminas | ||
US749551A (en) * | 1904-01-12 | goehring | ||
US2097730A (en) * | 1935-04-12 | 1937-11-02 | Mall Arthur William | Terrazzo grinding apparatus |
US2137329A (en) * | 1937-05-11 | 1938-11-22 | Carborundum Co | Abrasive article and its manufacture |
US2268869A (en) * | 1941-06-28 | 1942-01-06 | Perfect Circle Co | Bearing member |
US2426215A (en) * | 1944-11-11 | 1947-08-26 | Eastman Kodak Co | Thermoplastic synthetic resin optical lap |
US2597182A (en) * | 1949-03-31 | 1952-05-20 | Libbey Owens Ford Glass Co | Surfacing glass sheets or plates |
US2643494A (en) * | 1952-08-25 | 1953-06-30 | Norton Co | Grinding wheel |
US2760313A (en) * | 1955-05-12 | 1956-08-28 | American Viscose Corp | Abrasive wheel |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3177628A (en) * | 1961-06-26 | 1965-04-13 | Engelhard Hanovia Inc | Grinding of materials with hard abrasives |
US3236009A (en) * | 1961-06-26 | 1966-02-22 | Engelhard Hanovia Inc | Apparatus for surfacing |
US3662501A (en) * | 1971-01-28 | 1972-05-16 | Ibm | Method for polishing magnetic oxide materials |
US3662500A (en) * | 1971-01-28 | 1972-05-16 | Ibm | Method for polishing magnetic oxide materials |
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