DE10147707A1 - Highly effective abrasive composition and containing highly effective abrasive article for grinding a front glass panel of a cathode ray tube - Google Patents

Abstract

Abrasive article having a mixture of diamond and cubic boron nitride (CBN) derived from a highly effective composition with a volume mixing ratio of 8.5: 1.5 to 9.5: 0.5, one for fastening the abrasive layer by forming a three-dimensional Junction with the same composite substrate element provides an excellent grinding effect when used to grind a front glass panel of a cathode ray tube.

Description

Scope of the invention

The present invention relates to a highly effective Abrasive composition for sanding the front field of a cathode ray tube which is a mixture from in a binding material in a certain ver ratio scattered diamond and cubic boron nitride includes particles, as well as a specially shaped high effective abrasive article in which this Zu composition is used.

Background of the Invention

A cathode ray tube (CRT) consists of one Forehead glass field and a funnel-shaped glass body, the separately by hot pressing a glass jacket getting produced. With a conventional manufacturer Development process for a forehead field is the hot press pouring process molten glass a progressive Subjected to grinding process with the abrasive material rialien such. B. garnet, pumice and polished red ver can be applied to a finished front glass panel with a smooth surface ready for a screen display to deliver.

Highly effective abrasives, such as B. diamond and cubic chemical boron nitride (CBN), are widely used Grinding cast glass or steel objects have been used because they have greater hardness and Fe have strength as z. B. abrasive materials such as Alumina and silicon carbide (see U.S. Patent No. 6,096,107 and 6,200,360), whereby a grinding process ren, where a highly effective abrasive material is used, no environmentally harmful waste water testifies to how this works with the conventional methods Mud is the case.

Such a highly effective abrasive material will combined with a binding material and sintered to a highly effective abrasive article whose performance characteristics are based on particle size, Hardness, quality and structure of the highly effective Abrasive particles are affected, as well as by the type of binding material used and the porosi activity of the resulting composite material.  

A grinding object for grinding a front field A cathode ray tube can come in various forms be trained, as in various documents fenbt is. Thus, e.g. B. the Korean open Patent Application Publication No. 95-25832 highly effective abrasive article for grinding the front glass panel of a cathode ray tube in the form a rubber block, in the button elements made of diamond particles are integrated. Although the use of the this object does not produce waste water if only slide used as abrasive material, the polished surface glazed.

Summary of the invention

Therefore, a main object of the invention is an improved one, for use in manufacture the front glass panel of a cathode ray tube To provide abrasive composition that a excellent grinding effectiveness without the above mentioned te environmental or scratch problem.

Another object of the invention is one with such a composition with improvement resistance and service life To provide abrasive article.

In accordance with one aspect of the present Invention is a highly effective abrasive together setting for grinding the front glass field of a Katho provided the highly effective grinding  has medium particles and a binding material, wherein the highly effective abrasive particles are a mixture from diamond particles and cubic boron nitride particles (CBN) with a volume mixing ratio of 8.5: 1.5 to 9.5: 0.5.

In accordance with another aspect of the previous lying invention is an abrasive article for Grinding the front glass field of a cathode ray tube re provided the one by sintering the inventions highly effective abrasive composition according to the invention highly formed abrasive layer, and a substrate element for attaching the highly effective Has abrasive layer, the abrasive layer has a cylindrical projection which from a section of its lower surface extends outside, the substrate element, which on a section on its upper surface a groove points, which is shaped so that it the cylindrical Takes advantage of a tight fit, firmly with the Abrasive layer is connected, and so a parting surface that forms from the remaining portion of the bottom surface of the abrasive layer to the surface the projection extends.

Brief description of the drawings

The above mentioned, and other items and Merk Male of the present invention will become apparent based on the following description of the same, if this in conjunction with the associated drawings is used, each of which represents the following  

Fig. 1 is a perspective view of an example of a highly effective abrasive article according to the present invention;

Figure 2 is a cross-sectional view along side AA 'of the highly effective abrasive article of Figure 1;

Figures 3 and 4 show two examples of means for securely attaching the abrasive layer to a sub stratelement in the highly effective abrasive article according to the invention.

Figure 5 shows a conventional means for attaching the abrasive layer to a substrate member. and

Fig. 6 shows the change in grinding efficiency depending on the sintering conditions of highly effective abrasive articles made using a metallic binder material.

Detailed description of the invention

The highly effective abrasive composition of the before lying invention is characterized in that a specific mix of diamond and borni tridparticles (CBN) as a highly effective abrasive measure material is used, d. H. in accordance with the The present invention is the mixing ratio of diamond particles and cubic boron nitride particles  (CBN) in the volume range from 8.5: 1.5 to 9.5: 0.5. If Diamond particles used in excessive quantities surface can be prepared with it Grinding object with progressive grinding process drive suffer from glazing effects, which causes the Grinding efficiency is reduced. Keep falling the highly effective grinding particles during Ge need slightly from the grinding surface if ku little boron nitride particles are used in amounts, that exceed the specified range, causing the grinding effect is also reduced.

The highly effective abrasive particles are coated with egg a binding material with a volume mixing ratio from 1.5: 8.5 to 2.5: 7.5 combined.

The binding material can be metallic, or a mixture be made of a metal oxide and a resin, its Function is the highly effective grinding with telparticles during a high pressure sintering process to disperse and hold on to a strong compacted composite with a high degree to yield physical integrity.

Representative examples of a metallic bindema material used in the present invention can include particles of Fe, Cu, Sn, where an oxide consisting of it in the range from 30 to Average particle size is 50 µm has. If a mixture of a metal oxide and egg If resin is used as the binding material, it can the resin is preferably a phenolic resin  deln with the metal oxide component in a Mi ratio of 9: 1 to 7: 3 is combined.

In accordance with the present invention the highly effective abrasives of the invention together subjected to a hot press molding process in order to the abrasive article according to the invention with the spec to provide the infected structure.

The hot molding process can be done by filling the highly effective abrasives of the invention together be carried out in a mold so that they hot under high temperature, high pressure conditions is pressed, the mold being a prefabricated Substrate element holds that for fastening the through Sintering of the composition according to the invention witnessed grinding layer is designed.

Depending on the component of the binder used, the hot press casting process can be carried out appropriately at a temperature in the range from 150 to 800 ° C. and a pressure of 0.1 to 0.5 t / cm ² in an electric vacuum oven. If e.g. B. a metal such as copper or tin is used as the binding material, the sintering casting process can be carried out at a high temperature of 650 to 750 ° C at a pressure of 0.1 to 0.25 t / cm ² , while at Inte gration of resin in the binding material, the sintering casting process can be carried out at a low temperature of 150 to 200 ° C at a pressure of 0.25 to 0.35 t / cm ² , although the conditions depending on the Tg (Glass Transition temperature) and the decomposition temperature of the resin used can be changed.

The mold and the mounting substrate can be made from Stainless steel, carbon steel or other conventional materials known in this area be put, the mold during the under Vacuum carried out hot press casting process is.

In the present invention, the substrate element preformed so that it has a groove so that the by sintering the composition according to the invention obtained grinding layer be firmly attached to it can. That means that with the invention Abrasive the abrasive layer a cylindrical that has a tight fit from its lower surface towards the inside the groove of the sintered element extends.

Around the abrasive layer even tighter on the substrate a specific construction can continue to be installed Lich feature such. B. a flange, circumferential groove or Screw groove on the interface between the grinding Layer and the substrate element may be provided.

The grinding object for grinding the front glass panel of a cathode ray tube according to the present Invention can be in the form of e.g. B. a round or right kigen Blockes trained for the selected te grinding process is suitable. For example, a round Block shape preferably for a polishing or lapping process  machine that works in a rotating mode, and a rectangular shape for an AGM (aspherical) - Grinding machine that works in an oscillation mode.

Depending on the grinding method and the Zu composition of the binding material can the particle size esse and the strength index of the highly effective grinding middle particles are controlled appropriately. If e.g. B. that Binding material contains a resin component, and a Rotary grinding tool is used, have the high effective abrasive particles preferably a average particle size from 75 to 90 µm, and a strength index of 50 to 60, while at Using the vibration method the average Particle size smaller, in the range of 30 to Is 38 µm.

When using a metallic binding material and of a rotary grinding process show the highly effective Abrasive particles preferably an average particle size from 75 to 90 µm, and an Fe strength index from 50 to 60 as in the case above, but if an orbital grinding process is selected the average particle size is the highly effective abrasive particles preferably in Range from 30 to 38 microns, and the strength index of Diamond and cubic boron nitride particles each in Range from 50 to 60, and from 40 to 50.

If the particle size is larger than the upper limit the surface of the polished glass field becomes too rough while reducing the grinding effect if  it is less than the lower limit. Farther applies that if the strength index is greater than that upper limit is, the abrasive particles are not enough to break out at a suitable rate Renew grinding surface, reducing the grinding surface tends to glaze during the useful life shortened if it is below the lower limit.

Several implementations of the abrasive article according to the present invention are shown in the accompanying drawings. Fig. 1 is a perspective view of an embodiment of the abrasive article according to the present invention, and Fig. 2 is a cross-sectional view along the AA 'side in Fig. 1.

As shown in FIGS. 1 and 2, the OF INVENTION dung modern highly effective abrasive abrasive article 100 from a highly effective abrasive grinding layer 110 and a substrate member 120 for attachment of the abrasive layer, wherein the lower portion of the abrasive layer 110 having a cylindrical projection whose cylindrical flange 141 is positioned at the lower end thereof, and which extends into and fits into the preformed substrate member 120 with a close fit.

The lower part of the substrate element 120 is equipped on its outer surface with a circular groove 130 , which is used to load the abrasive article onto a support such. B. a rubber block is provided. The circular flange 141 prevents the abrasive layer from detaching from the substrate member when the object is vibrated in the axial direction.

FIGS. 3 and 4 illustrate two further embodiments of he inventive abrasive article. As seen from Fig. 3 and 4 it can be seen, the means for BEFE stigung the highly effective abrasive abrasive layer on the substrate member, an additional structural feature, ie, a bottom at the Surface 160 of abrasive layer 110 positioned circumferential groove 142 , or a screw groove 143 provided on the outer surface of cylindrical projection 140 .

The following examples are for the purpose of ver illustrative, and are not intended to limit the scope of the inven limit dung.

example 1

To a binding material consisting of 75 percent by weight of a bronze-based powder (M325, a product of KENNAMETAL COMPANY, USA) and 25 percent by weight of a tin powder, highly effective abrasive particles made of diamond and boron nitride were added in various ratios, as shown in Table 1, whereby the amount of the highly effective abrasive particles based on the total weight of the resulting mixture was 25 percent by volume, and the resulting mixture was homogenized using a rotary drum to obtain various highly effective abrasive compositions.

A fastened substrate member 120 having a shape corresponding to Fig. 3, which was made of SS41, which has previously been produced using a numerically controlled machine, has been positioned in a mold, whereby the above-mentioned abrasive layer composition was introduced via the substrate member. The mold was sealed with a carbon stamp, positioned in an electric vacuum oven, and subjected to sintering at a pressure of 0.2 t / cm ² for 20 minutes at 700 ° C to provide a sintered, highly effective abrasive article to provide the form shown in Figs. 1 and 2.

Highly effective abrasive articles prepared in this manner were integrated into a round rubber block using conventional integration techniques, and the resulting grinder was loaded into a lapping or polishing grinder and used to grind 200 front glass panels of cathode ray tubes in a rotating mode at 0.15 kg / cm ^{2 used} for the duration of 30 seconds to evaluate their grinding effectiveness, which is represented by the amount of glass removed. The result is shown in Table 1.

Table 1

As can be seen from Table 1, the grinding falls effectiveness with progressive grinding processes decrease rapidly when the relative amount of cubic boron nitride is not in the range of 5-15%.

Example 2

The procedure of Example 1 was with the Aus repeated that during the establishment of the Mi  ratio of diamond to cubic Borni trid to 9.5: 0.5 the amount, the average par particle size and the strength index of the used highly effective abrasive particles has been changed, as shown in Table 2 for highly effective grinding to provide medium particles.

The highly effective abrasive grinder was loaded into a lapping or polishing machine and used to grind a 15 "cathode ray tube glass panel for 30 seconds at 5.5-7 Hz and 0.15 kg / cm ^2. The grinding efficiency and the roughness of the machined surface were measured. The device used to measure the roughness of the surface was Surftest301 ™ (pen model), Japan, Mitsutoyo Company.

Table 2

As can be seen from Table 2, the grinding Effectiveness unsatisfactory (see Business Run No. 2-1 to 2-3 and 2-7 to 2-11) if the amount of ver did not use abrasive particles in the range of 15-25% of the present invention, or the Fe strength index is less than 50, while for a Fe Stability index of over 60 or with a particle size If the ground surface becomes too rough over 90 µm (see Business Run Nos. 2-4 to 2-6 and 2-15 to 2-18). On the other hand, if the particle size is below 75 µm the grinding effectiveness becomes unsatisfactory low (see Business Run No. 23). Continue to point the others, in Wirtsch. Run numbers 2-12 to 2-14, 2-19 to 2-22 and 2-24 to 2-26 prepared items, where highly effective abrasive particles with a not within the scope of the present invention particle size and strength value poor grinding effectiveness.

Example 3

The procedure of Example 1 was with the Aus repeated that during the establishment of the Mi ratio of diamond to cubic Borni trid to 9.5: 0.5 the amount, the particle size and the Strength index of the highly effective abrasive particles was changed as shown in Table 2 to a number of highly effective abrasive particles  to provide, each in a rectangular Rubber block were integrated to make a sanding device manufacture.

The grinder thus obtained was loaded into an AGM (Orbital Aspherical Grinding Machine / Orbitale aspherical grinder) (which is operated in an oscillation mode), and for grinding a 29 "cathode ray tube glass field for 5.5 seconds at 5.5 -7 Hz and 0.15 kg / cm ^2. The grinding efficiency and the roughness of the machined surface were measured as in Example 2. The result is shown in Table 3.

Table 3

As in Table 2, the result shows in Tabel le 3 that a satisfactory grinding efficiency and surface smoothness can only be achieved if Particle size, strength index and the amount of Abrasive particles within the specified Fields of the present invention are.

Example 4

The procedure of Example 1 was repeated with the exception that during the definition of the mixing ratio of diamond to cubic boron nitride to 9.5: 0.5, the average particle size to 50 to 60 μm, and the strength index to 90 to 75 , Sintering temperature and pressure as shown in Fig. 6 were changed to provide abrasive articles with different sintering characteristics. The grinding efficiency of each of the thus prepared abrasive articles was measured and represented by a 10-based relative value set for the obtained abrasive article prepared by sintering at 700 ° C and 0.10 t / cm ² . The result is shown in FIG. 6.

Fig. 6 shows that an abrasive article prepared using a bronze-based metal as a bonding material is suitably sintered at a temperature of 650 to 750 ° C and a pressure of 0.10 to 0.25 t / cm ² .

Example 5

The procedure of Example 1 was repeated using a 9.5: 0.5 mixed powder of diamond and cubic boron nitride with a particle size of 50 to 60 µm and a strength index of 90 to 75, with the exception of using additional runs a phenolic resin composition containing 10 to 30% iron oxide as a binder, using a steel mold and sintering under conditions of 160 to 170 ° C and 0.25 to 0.35 t / cm ² to provide two types of abrasive articles which the in Fig. 2 have structure shown.

Table 4

The result in Table 4 shows that the grinding layer of the respective abrasive article much stronger attached to the substrate member than that a conventional abrasive article.

While the invention is in connection with the above specific remarks should have been described recognized that the various changes and Changes made by professionals in the field can be made to the invention,  without departing from the scope of the invention as he is defined by the appended claims.

Claims (12)

1. Highly effective abrasive composition for Grinding the front glass field of a cathode jet tube, the highly effective abrasive part kel and a binding material, the highly effective abrasive particles a mixture made of diamond particles and cubic boron nitride particles (CBN) with a volume mixing ratio from 8.5: 1.5 to 9.5: 0.5. 2. The composition of claim 1, characterized in that the highly effective abrasive particles average particle size from 75 to 90 µm, and a strength index of 50 to 60 sen.   3. Composition according to claim 1, characterized in that the highly effective abrasive particles average particle size from 30 to 38 µm, and a strength index of 50 to 60 sen. 4. Composition according to claim 1, characterized in that the diamond particles an average part kel size from 30 to 38 microns, and a Festig pity index from 50 to 60, and the cubic Borni tridparticle an average particle size from 30 to 38 µm, and a strength index of Have 40 to 50. 5. Composition according to claim 1, characterized in that the highly effective abrasive particles with one Binding material with a volume mixing ratio from 1.5: 8.5 to 2.5: 7.5 are combined. 6. The composition according to claim 1, characterized in that the binding material is metallic, or a mixture is made of a metal oxide and a resin. 7. The composition according to claim 6, characterized in that the resin content of the metal oxide resin mixture in the loading ranges from 70 to 90 percent by volume.   8. Abrasive article ( 100 ) for grinding the front glass panel of a cathode ray tube which has a highly effective abrasive abrasive layer formed by sintering the highly effective abrasive composition according to any one of claims 1 to 7, and a substrate member ( 120 ) for attaching the highly effective abrasive abrasive layer wherein the abrasive layer ( 110 ) has a cylindrical protrusion ( 140 ) extending outwardly from a portion of the lower surface ( 160 ) thereof, the substrate member ( 120 ) having a groove on a portion on the upper surface thereof has, which is shaped so that it receives the cylindrical projection ( 140 ) with a close fit, is fixedly connected to the abrasive layer ( 110 ), and thus forms a separating surface, which is from the remaining portion of the lower surface ( 160 ) Abrasive layer ( 110 ) extends to the surface of the protrusion ( 140 ). 9. Article according to claim 8, characterized in that an additional structural feature for fastening the abrasive layer ( 110 ) on the substrate element ( 120 ) is provided on the surface. 10. The article of claim 9, characterized in that the additional structural feature of a on a nem lower portion of the cylindrical projection ( 140 ) formed flange ( 141 ), a circumferential groove ( 142 ) which is posi tioned on the portion of the parting surface, where the lower surface ( 160 ) of the abrasive layer ( 110 ) meets the upper surface of the substrate element ( 120 ), a screw groove ( 143 ) provided on the outer circumference of the cylindrical projection ( 140 ), and a combination consisting thereof is selected. 11. A method of manufacturing an abrasive article ( 100 ) for grinding the front glass panel of a cathode ray tube which comprises the steps of loading a prefabricated substrate element ( 120 ) into a mold, introducing the highly effective abrasive composition according to any one of claims 1 to 8 over the substrate element ( 120 ), sealing the mold and hot pressing at a temperature in the range of 150 to 800 ° C at a pressure of 0.1 to 0.5 t / cm ² . 12. The method according to claim 11, characterized in that the abrasive article ( 100 ) by the sintering of the highly effective abrasive composition ge formed highly effective abrasive abrasive layer, and a substrate element ( 120 ) for fastening the highly effective abrasive abrasive layer, wherein the abrasive layer ( 110 ) has a cylindrical projection ( 140 ) extending outwardly from a portion of its lower surface ( 160 ), the substrate member ( 120 ) having a groove on a portion on the upper surface thereof which is shaped that it receives the cylindrical projection ( 140 ) with a close fit, is fixedly connected to the abrasive layer ( 110 ), and thus forms a separating surface which extends from the remaining portion of the lower surface ( 160 ) of the abrasive layer ( 110 ) to the surface of the projection ( 140 ) extends.