Patent Application
20180369988
The present disclosure is directed to polishing tools and methods of making and using the same. In particular, the disclosure is directed hard and high efficiency polishing tools to be used in conjunction with computer numerical control (CNC) machines.
Innovations in user interfaces incorporating touch technology have exploded over the last few years. Recent innovations in the field, e.g., One Glass Solution (OGS) touch technology, allow for thinner, lower cost touch panels in electronic devices while providing a brighter user interface. OGS touch technology works by reducing the number of glass layers. As such, the glass used for these touch interfaces is now very thin. Often, to create desired shape of the glass interface, the edge of the glass is ground down. During the grinding process, chips of about 20 μm to about 30 μm and subsurface damage may be caused around the edges of the glass. This damage should be removed to increase the edge strength of the glass. Traditional methods of removing glass chips and subsurface damage include acid etching and brush polishing. Acid etching, depending on the strength of the glass, may take about 20 minutes to about 40 minutes to polish an edge of a glass substrate. Additionally, acid etching processes may require expensive surface protection film and additional safety measures.
Brush polishing also presents challenges. For example, polishing tool variance makes it difficult to mass-produce consistent glass edges. Furthermore, brush polishing may take up to 3.5 hours to polish an edge of a glass substrate. The brush polishing process itself also has limitations. While brush polishing may be performed using CNC machines, the polishing tools experience fast and excessive wear as they polish an edge of a glass substrate. Traditional methods require compensating for this wear by moving the center of the polishing tool closer to the glass edge. Generally, compensation occurs after the polishing tool has traversed about 200 mm of a glass edge. Typical compensation values are anywhere from about 30 μm to about 100 μm. As such, there may be uneven processing of the glass edge and the glass may experience edge burning where the tool is forced back in contact with the glass edge. As a result, the glass edge may need to be polished at least 3 times before the chip and subsurface damage is removed.
Accordingly, a need exists for new polishing tools and methods that improve the edge quality of glass in less time than traditional tools while avoiding edge burn and uneven processing.
In one embodiment, a polishing tool includes a stem and a polishing material bonded to the stem. The polishing material includes, in volume concentration, about 18% to about 42% phenolic resin, about 18% to about 30% zinc oxide, about 1% to about 10% magnesium oxide, a cooling agent, and an abrasive.
In another embodiment, a method of creating a high efficiency polishing tool configured to be received by a CNC machine includes mixing a polishing material, the polishing material including, in volume concentration, about 18% to about 42% phenolic resin, about 18% to about 30% zinc oxide, about 1% to about 10% magnesium oxide, a cooling agent, and an abrasive. The method further includes feeding the polishing material into a mold, pre-pressing the polishing material within the mold, curing the polishing material, holing the polishing material, assembling a stem to the polishing material by passing the stem into the hole of the polishing material, and bonding the polishing material to the stem.
In yet another embodiment, a method of polishing an edge of a glass substrate using a CNC machine includes preparing the glass substrate in the CNC machine, the prepared glass substrate having a perimeter defined by an edge of the glass substrate, and attaching a polishing tool having a polishing material to the CNC machine. The polishing material includes, in volume concentration, about 18% to about 42% phenolic resin, about 18% to about 30% zinc oxide, about 1% to about 10% magnesium oxide, a cooling agent, and an abrasive. The method further includes aligning the polishing tool with the edge of the glass substrate; and polishing the edge of the glass substrate, wherein a stem of the polishing tool continuously moves closer to the edge of the glass substrate as the polishing tool traverses the perimeter of the glass substrate.
Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.
The embodiments set forth in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
Embodiments of the present disclosure are directed to polishing tools and methods of polishing glass substrates. Referring generally to the figures, embodiments of polishing tools and methods of polishing glass substrates provided herein allow for the reduction of chips and subsurface damage on an edge of a glass substrate. The reduction of chips and subsurface damage on an edge of a glass substrate increases the edge strength of the glass substrate and thus provides an overall better quality glass substrate to be used in various practical applications. Furthermore, the methods utilized herein may decrease instances where the glass substrate experiences edge burn during edge polishing processes. The various polishing tools and methods of polishing glass substrates are described in more detail herein with specific reference to the corresponding figures.
Some embodiments disclosed herein are directed to polishing tools having a stem and a polishing material. In these embodiments, the polishing tools are configured to be received by a CNC machine, wherein the CNC machine executes a polishing process to engage the polishing material of the polishing tool with an edge of a glass substrate to polish away chips and/or subsurface damage. In some embodiments, the polishing material may include, in volume concentration about 18% to about 42% phenolic resin, about 18% to about 30% zinc oxide; about 1% to about 10% magnesium oxide; a cooling agent; and an abrasive. Methods of making such polishing tools and using such polishing tools to polish a substrate of glass are also disclosed in embodiments.
A shoulder 225 extends from the stem 220. In embodiments, the shoulder 225 may be integrally formed with the stem 220 of the polishing tool 200. The shoulder 225 and the stem 220 may be formed through traditional machining techniques such as, but not limited to, milling. In other embodiments, the shoulder 225 may be constructed separately from the stem 220 and is separately bonded to the stem 220. The shoulder 225 and stem 220 are configured to be received by a spindle 105 of a CNC machine 100 (shown in
Adjacent to the shoulder 225 is a polishing material 210 that may be bonded to the stem 220. Referring to specifically to
The polishing material 210 is used to polish a glass substrate, specifically an edge of a glass substrate. The polishing material 210 is configured to remove both chips and subsurface damage that may weaken the edge strength or dull the appearance of the glass substrate while leaving a smooth edge. As such, characteristics of the polishing tool include being both hard enough the cut into an edge of a glass substrate, but flexible enough to engage the glass substrate in such a way as to produce a smoothly finished edge. Table 1 below tabulates the various constituents of an example composition of the polishing material, which will be described in greater detail below.
In some embodiments, the polishing material 210 includes a base composition and super additions in addition to the base composition. In embodiments, the base composition includes a binder. The binder may be the largest constituent of the base composition and act to bind any other constituents of the polishing tool. The binder may be present, in volume concentration, from about 18% to about 42% of the base composition. In other embodiments, the binder may be present, in volume concentration, from about 20% to about 40% the base composition. It is noted that if too high a concentration of binder is used, the polishing tool 200 will be unable to polish because the polishing material 200 will be unable to grind an edge of a glass substrate. If too small a percentage of binder is used, the binder will be unable to polish an edge of a glass substrate because the polishing tool 200 will be unable to maintain its shape so as to adequately interface with an edge of a glass substrate. As a non-limiting example, the binder may be a phenolic resin. Phenolic resins provide both bonding properties as well as flexibility to the polishing material 210.
The polishing material 210 includes a fluxing and glazing agent. The fluxing and glazing agent may be present, in volume concentration, from about 18% to about 30% of the base composition. In some embodiments the fluxing and glazing agent may be present, in volume concentration, from about 20% to about 28% of the base composition. The fluxing and glazing agent may be provided to the polishing material 210 as a powder. As a non-limiting example, the fluxing and glazing agent may be zinc oxide (ZnO).
The polishing material 210 further includes an anti-scorching agent. The anti-scorching agent may be present, in volume concentration, from about 1% to about 10% of the base composition. The anti-scorching agent may be provided to the polishing material 210 as a powder. The anti-scorching agent may be, without limitation, magnesium oxide (MgO).
The polishing material 210 further includes at least one polishing agent. The at least one polishing agent may be present, in volume concentration, from about 16% to about 28% of the base composition. A non-limiting polishing agent may be ferric oxide (Fe2O3) and may be present, in volume concentration, from about 16% to about 28% of the base composition. The ferric oxide may be provided to the polishing material 210 as a powder. In some embodiments, a second polishing agent is provided. In embodiments where there is a second polishing agent, the second polishing agent may be present, in volume concentration, about 13% to about 29% of the base composition. The second polishing agent may be silicon carbide (SiC) in one non-limiting example. It is noted that too much polishing agent may lead to too hard an interface with between a glass substrate and the polishing tool, such that a smooth finish may not be rendered. Similarly, too little polishing agent will prevent the polishing tool 200 from effectively polishing an edge of a glass substrate because the polishing qualities of the first and second polishing agents may be overcome and masked by the other constituents of the base composition of the polishing material 210.
The polishing material 210 further comprises a cooling agent that promotes cooling of the polishing material 210 after forming the polishing material 210, as described in greater detail below. Further, the cooling agent may inhibit or slow an increase in temperature of the polishing tool 200 while the polishing tool 200 polishes an edge 132 of the glass substrate 130. The cooling agent of the polishing material 210 may be present, in volume concentration, from about 6% to about 32% of the base composition. As a non-limiting example, the cooling agent is copper (Cu) powder.
The polishing material 210 further comprises a constituent adding flexibility to the polishing material 210. Increased flexibility allows the polishing tool 200 to more fully engage an edge 132 of a glass substrate 130. The constituent adding flexibility to the polishing material 210 may be present, in volume concentration, from about 10% to about 14% of the base composition. In some embodiments, the constituent adding flexibility to the polishing material 200 is a rubber material and is added to the base composition as a powder. Some examples of non-limiting rubber materials are vulcanized elastomeric material, ethylene propylene diene monomer (EPDM), butyl and other natural rubber compounds. It should be noted that adding too little rubber to the base composition may result in an inflexible polishing material 210 that wears too fast. Similarly, adding too much rubber may cause the polishing material 210 to be too flexible such that the polishing tool 200 does adequately engage an edge of a glass substrate when polishing.
The polishing material 210 further comprises an abrasive added as a super addition of the base composition. As used herein, a super addition is a material added to a composition beyond the base composition. For example, if a base composition comprises 100 grams a super addition of 10% would be 10 grams of the super addition material added to the 100 grams of the base composition. The abrasive may provide cutting and polishing capabilities. Some non-limiting examples of abrasives include carborundum, diamond, nickel-plated carborundum or nickel-plated diamond. Carborundum, also known as silicon carbide (SiC), may be naturally occurring or synthetic. Carborundum or diamond may be nickel-plated through a variety of methods, such as, without limitation, electroless nickel plating. Electroless nickel-plating is an auto-catalytic chemical process used to deposit a layer of nickel-phosphorus or nickel-boron alloy on a solid workpiece. The nickel-plating may increase the adhesive properties of the binder such that there is a stronger bond between the binder and the abrasive. A grit size of the abrasive may be from about 1 μm to about 5 μm. Grit size refers to the size of the individual particles of the abrasive material. Larger grit sizes remove more material from an edge of a glass substrate. In glass edge polishing, only about 20 μm to about 30 μm of glass is removed, as such a finer grit size may be required so as not to remove too much of the glass and to leave a smooth finish. The abrasive may be added to the polishing material 210 as a super addition, in volume concentration, from about 100% to about 200% of the base composition. In some embodiments, the abrasive is added to the polishing material 210 as a super addition, in volume concentration, from about 148% to about 152% of the base composition.
Methods of making polishing tools according to one or more embodiments described herein are provided.
As shown in block 310, the materials that make up the base composition and any super addition materials are mixed together. At least a portion of the mixed polishing material 210 may then be fed into a mold at block 320. The mold may be configured to give the polishing material 210 a desired shape and size. The portion of the polishing material 210 within the mold may then be pre-pressed at block 330. As an example and not a limitation, the pre-pressing step 330 may occur at a temperature from about 130° C. to about 140° C. for about 1 minute to about 6 minutes. In some embodiments, the pre-pressing step 330 may be completed in one step. In other embodiments, the feeding step 320 and the pre-pressing step 330 may be completed in multiple cycles, wherein a portion of the polishing material 210 is fed into the mold and is then pre-pressed, and then more of the polishing material 210 is fed into the mold and also pre-pressed. The cycles may go on until the mold has pressed an amount of polishing material 210 needed for a complete polishing tool 200. In some embodiments, the feeding and pre-pressing steps 320, 330 include 8 to 10 cycles.
After the feeding and pre-pressing steps 320, 330, the polishing material 210 may go through a curing process at block 340. As an example and not a limitation, the polishing material 210 is cured at a temperature of about 170° C. to about 190° C. for about 85 to about 95 minutes. Once the polishing material 210 has cured a desired amount, the polishing material 210 is removed from the mold.
Once the polishing material 210 has been removed from the mold, the polishing material 210 may go through a holing step at block 350. The holing step 350 forms a passage 215 through the approximate center of the polishing material 210 such that the polishing material 210 may be assembled to the stem 220 (as shown in
At block 360, a stem material is provided. As described above, the stem 220 may be made of steel or steel alloys such as stainless steel. As such, a billet of the chosen material may be provided and then shaped into a desired stem shape at block 370. The stem 220 may have a variety of shapes. In embodiments, the stem 220 may be may have a cylindrical shape. Extending from approximately a central portion of the stem 220 may be a shoulder 225. The shape of the stem 220 and its shoulder 225 may be mechanically formed using a variety of machining tools. One non-limiting machining tool may be a milling machine.
At block 380, the stem 220 may be assembled and bonded to the polishing material 210. As shown in
As noted herein above, the polishing tools described herein may be employed in improved methods of edge-polishing glass substrates. An example method of polishing an edge 132 of a glass substrate 130 using a CNC machine 100 and an embodiment of the above described polishing tool 200 is disclosed with reference to
The glass substrate 130 extends in both the longitudinal direction, x, and the lateral direction, y. The glass substrate 130 may comprise a perimeter defined by an edge 132 of the glass substrate 130. The glass substrate 130 may be strengthened or unstrengthened. Non-limiting examples of strengthened glass include ion-exchanged chemically strengthened glass or thermally tempered glass. Referring to
As described herein, compensation refers to moving the stem 220 of the polishing tool 200 closer to the edge 132 of the glass substrate 130 as the polishing material 210 of the polishing tool 200 wears away. The wear of the polishing material 210 may be substantially uniform as the polishing tool 200 traverses the edge 132 of the glass substrate 130. As such, a continuous compensation value may be set such that the stem 220 of the polishing tool 200 may continuously and gradually move closer toward the edge 132 of the glass substrate 130 instead of abruptly moving the stem 220 of the polishing tool 200 toward the edge 132 of the glass substrate 130. Compensation values may vary based on the strength of the glass. For chemically strengthened glass, the compensation value may be between about 0.15 μm/mm to about 0.28 μm/mm.
Still referring to
As such, the polishing tool 200 may be aligned with the edge 132 of the glass substrate 130. The polishing tool 200 may polish the edge 132 of the glass substrate 130 while traversing the predetermined polishing route 250, wherein the stem 220 of the polishing tool 200 continuously moves closer to the edge 132 of the glass substrate 130. The polishing tool 200 may traverse the polishing route 250 at a feed rate of about 1,400 mm/min to about 1,600 mm/min. The polishing tool 200 may remove the chip of glass, described herein, in less than three passes of the polishing tool 200 about the perimeter of the glass substrate 130. In some embodiments, the polishing tool 200 may remove the chip of glass in a single pass of the polishing tool 200 about the perimeter of the glass substrate 130.
It should now be understood that the embodiments described herein provide for polishing tools and the methods of polishing a glass substrate to reduce chips and subsurface damage present on a glass substrate that may otherwise decrease the edge strength of a glass substrate. Thus, the polishing tools and methods of polishing a glass substrate described herein may increase an edge strength of a glass substrate while avoiding unsightly edge burn by continuously compensating the polishing tool toward an edge of a glass substrate.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2015/097672 | 12/17/2015 | WO | 00 |
