US20160221148A1

US20160221148A1 - Glass sleeve internal polishing

Info

Publication number: US20160221148A1
Application number: US15/007,337
Authority: US
Inventors: Thierry Luc Alain Dannoux
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2015-01-30
Filing date: 2016-01-27
Publication date: 2016-08-04
Also published as: CN105834891A

Abstract

A magnetic polisher and a method of use magnetic polisher for polishing a glass sleeve are described. The magnetic polisher may comprise at least one rotatable driver and at least one rotatable polishing tool. The at least one rotatable driver may comprise driver magnetic material. The at least one rotatable polishing tool may comprise tool magnetic material and a first polishing surface. At least one of the driver magnetic material and the tool magnetic material may be a magnet. The driver and polishing tool may be configured to be magnetically coupled with a workpiece. The workpiece may have at least a first internal surface to be polished. The workpiece may be located between the first polishing surface and the driver. The rotation of the driver about an axis may cause rotation of the first polishing surface against the first internal surface.

Description

This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 62/109857 filed on Jan. 30, 2015 the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

The disclosure relates to systems and methods for polishing internal surfaces of a hollow structure, and more particularly to a system, such as a magnetic polisher, for polishing an internal surface of a glass sleeve, and methods for polishing a glass sleeve to produce a three-dimensional formed glass cover for a handheld smart phone or other consumer electronic device. The glass cover optionally may be sleeve-shaped.

SUMMARY

The present disclosure relates, in various embodiments, generally to a magnetic polisher for polishing internal surface of glass sleeve. The magnetic polisher may comprise at least one rotatable driver and at least one rotatable polishing tool. The at least one rotatable driver may comprise driver magnetic material. The at least one rotatable polishing tool may comprise tool magnetic material and a first polishing surface. At least one of the driver magnetic material and the tool magnetic material may be a magnet. The driver and polishing tool may be configured to be magnetically coupled with a workpiece. The workpiece may have at least a first internal surface to be polished. The workpiece may be located between the first polishing surface and the driver. The rotation of the driver about an axis may cause rotation of the first polishing surface against the first internal surface.
The present disclosure relates, in various embodiments, to a method for polishing a glass sleeve with a flattened portion. The method may be useful in manufacturing a sleeve-like structure. The method is carried out by providing a glass sleeve. The glass sleeve may have at least one substantially flat internal surface extending along a longitudinal axis and an internal opening extending along the longitudinal axis enclosing a space. A rotatable polishing tool may be introduced to polish the glass sleeve. The rotatable polishing tool may include a magnetic material and a first polishing surface which may be brought into the space within the glass sleeve. The first polishing surface may be brought into contact with the substantially flat internal surface. A rotatable driver may be introduced. The rotatable driver may include a magnetic material outside the glass sleeve. The tool magnetic material may be a magnet so that the driver may magnetically couple with the polishing tool. The driver may be rotated, causing the polishing tool to rotate.
Additional features and advantages of the present disclosure 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.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity or conciseness.

FIG. 1 is a schematic side view of a magnetic polisher in use according to an embodiment;

FIG. 2 is a schematic side view of a magnetic polisher in use according to another embodiment;

FIG. 3 is a top view of a rotatable polishing tool in use according to the embodiment of FIG. 2;

FIG. 4 is a perspective view of a polishing pad usable, for example, in the embodiments of any Figure;

FIG. 5 is a schematic side view of a magnetic polisher usable, for example, in the embodiments of any Figure;

FIG. 6 is a schematic side view of another type of magnetic polisher usable, for example, in the embodiments of FIGS. 1-4 and 7; and

FIG. 7 is a flow chart illustrating a method for polishing a glass sleeve according to one embodiment.

The following reference characters are used in this specification:


100	Magnetic polisher
102	Axis
110	Rotatable driver
120	Rotatable polishing tool
122	Polishing surface
130	workpiece
132	First internal surface
140	Driving motor
140	Variable spacer
150	Translation stage
160	Magnet for driver
170	Magnet for polishing tool
180	Polishing pad
210	Shaft
410	radial slots
500	Driving pad
510	Driver polishing surface
520	External surface
600	Internal spring
610	Second polishing surface
620	second internal surface
630	Second non-magnetic polishing pad
640	Polishing paper
700	Method for polishing a glass sleeve
710	First step of the method
720	Second step of the method
730	Third step of the method
740	Fourth step of the method
750	Fifth step of the method

The foregoing summary, as well as the following detailed description of certain inventive techniques, will be better understood when read in conjunction with the figures. It should be understood that the claims are not limited to the arrangements and instrumentalities shown in the figures. Furthermore, the appearance shown in the figures is one of many ornamental appearances that can be employed to achieve the stated functions of the apparatus.

DETAILED DESCRIPTION

The present disclosure can be understood more readily by reference to the following detailed description, drawings, examples, and claims, and the previous and following description. However, before the present compositions, articles, devices, and methods are disclosed and described, it is to be understood that this disclosure is not limited to the specific compositions, articles, devices, and methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
The following description of the disclosure is provided as an enabling teaching of the disclosure in its currently known embodiments. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the disclosure described herein, while still obtaining the beneficial results of the present disclosure. It will also be apparent that some of the desired benefits of the present disclosure can be obtained by selecting some of the features of the present disclosure without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present disclosure are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Thus, the following description is provided as illustrative of the principles of the present disclosure and not in limitation thereof.
Disclosed are materials, compounds, compositions, and components that can be used for, can be used in conjunction with, can be used in preparation for, or are embodiments of the disclosed method and compositions. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds may not be explicitly disclosed, each is specifically contemplated and described herein.
Reference will now be made in detail to the present preferred embodiment(s), examples of which are illustrated in the accompanying drawings. The use of a particular reference character in the respective views indicates the same or like parts.
As noted above, broadly, this disclosure teaches a magnetic polisher and a process to polish an internal surface of a glass sleeve by using a magnetic polisher. The present disclosure involves a process for grinding and polishing the internal surface of a glass sleeve which presents a narrow open frontal area (6-8×60-70 mm) and a deep cavity (120 -140 mm), preventing use of conventional finishing techniques. The glass surface quality, potentially affected by tube reforming processes, may need to be compatible with display applications, optical clarity, non-local deformations or local surface defects, such as pits, scratches, or dimples. These defects may typically have roughness higher than 0.2 nm, for example. The current disclosure may involve a magnetic coupling between one or more inner rotatable polishing tools put in rotation by an external rotating motor. It may also involve a stage or other translation mechanism in order to manage the polishing of a generally rectangular surface with a substantially round tool. The magnetic coupling may be insured by a North or South pole orientation of magnets.
The disclosure may present many advantages, such as internal surface finishing of non-accessible flat glass cavity, thin polishing tool being able to enter a fragile narrow glass cavity; magnetic coupling between the polishing tool and an external rotating motor, flexible and compliant polishing tool being able to follow a generally flat surface that could involve a very large radius of curvature (such as several meters). The advantages may further include combined translation motion in order to be able to generate a flat polished surface, use of different grain size grinding and polishing mediums that may be coated papers, fabric or polyurethane pads with free abrasive, possible double side polishing, internal and external at the same time, possible double internal side polishing, cost effective technique that may be applied to finished sleeve enclosure or long sleeve preforms before cutting and edge finishing, control of the grinding and polishing force by variation of the power/density of magnetic elements and/or of the magnetic gap in between the driving and the grinding parts.
As used herein, the term “sleeve” describes a three-dimensional, tubular glass article having a non-circular cross section and an aspect ratio greater than 1. The aspect ratio is the ratio of the largest and smallest diameters of the cross section of the tubing or sleeve. The aspect ratio has a minimum value of 1 by definition for a round or axisymmetric tube. The aspect ratio has a value larger than 1 for a flattened sleeve. Optionally in any embodiment, aspect ratios from about 1.5 to about 50, optionally from about 3 to about 39, optionally from about 5 to about 25, optionally from about 5 to about 15, optionally from about 7 to about 11, optionally from about 18 to about 28, are contemplated.
While most of the embodiments herein are used particularly in application to sleeve glass enclosures, it is contemplated that the same method could be applied more widely, for example with an additional step of cutting the tubes in half or severing optically flat portions to provide for a 3D shaped cover glass, touch screen, or other part.
As shown in the Figures, the magnetic polisher 100 may include at least one rotatable driver 110 and at least one rotatable polishing tool 120. The at least one rotatable driver 110 may include driver magnetic material, such as a magnet 160. The at least one rotatable polishing tool 120 may include tool magnetic material, such as a magnet 170, and a first polishing surface 122. In one embodiment, the at least one magnet 160 or 170 may include a permanent magnet, such as neodymium magnet, samarium-cobalt or an alloy of neodymium, neodymium-iron-boron (NIB) magnet, for example. The at least one of the driver magnetic material and the tool magnetic material may comprise a magnetic neodymium alloy, such as neodymium-iron-boron magnet. In another embodiment, the magnet 160 for driver magnetic material may be electromagnet.
Optionally in any embodiment, the rotatable driver 110 and the polishing tool 120 may be configured to be magnetically coupled with a workpiece 130, such as a glass sleeve. The rotatable driver 110 may be connected to a driving motor 140. The rotatable driver 110 may be operated at various speeds ranging from 200 to 800 rpm, for example. The workpiece 130 may have at least a first internal surface 132 to be polished. The workpiece 130 may be located between the first polishing surface 122 and the driver 110 so that rotation of the driver 110 about an axis 102 may cause rotation of the first polishing surface 122 against the first internal surface 132. The first polishing surface 122 may be defined by a non-magnetic polishing pad 180. The non-magnetic polishing pad 180 may be used in order to prevent any impact on the magnetic coupling between the polishing pad 180 and the rotatable driver 110. A magnetic polishing pad 180 may alternatively be used, if desired.
The magnetic polisher 100 may further include a variable spacer 140. The variable spacer 140 may be configured to adjust and maintain the axial distance between the rotatable driver 110 and the rotatable polishing tool 120, while the first internal surface 132 is located between the first polishing surface 122 and the driver 110 to provide the desired normal force between the first polishing surface 122 and the first internal surface 132. The variable spacer 140 may allow a fine tuning of the grinding or polishing force. The variable spacer may vary from 2 to 10 mm for 50 N to 5 N corresponding forces, for example. In another embodiment, the variable spacer may be less than 2 mm or more than 10 mm depending on the workpiece 130. There may be many advantages of using a variable spacer 140. For example, as one of the advantages, the rotatable driver 110 may be configured to remain out of contact with the workpiece 130, such as a glass sleeve, when the rotatable driver 110 and the polishing tool 120 are magnetically coupled and the first polishing surface 122 is rotating against the first internal surface 132.
The magnetic polisher 100 may further include a translation stage 150 upon which either the workpiece 130 or the rotatable driver 110 may be mounted. The translation stage may allow the workpiece 130 to be moved relative to the magnetic polisher 100 generally perpendicular to the rotation axis 102. As shown in FIG. 2, for example, the translation stage 150, such as a translation belt, may be connected to a shaft 210 of the motor so that one motor 140 may control several, such as four, rotatable drivers 110. The rotatable drivers 110 may in turn control several, such as four, polishing tools 120 to have individual tool 120 overlapping for uniform polishing (as shown in FIG. 3). In this way, the internal surface polishing may be operated on a long sample, such as exceeding one meter, on a multi-head polishing set-up. The translation belt may form a rotating system.
As shown in FIG. 3, in one embodiment, the workpiece 130, such as a glass sleeve, to be internally polished may sit on the translation stage 150, such as a translation belt, being also motorized in order to insure the polishing of the whole internal surface. The translating support may move on both directions covering the whole surface at a rate of 2 to 10 cycles per minute, for example. In another embodiment, the translation stage 150 may be used to translate the rotatable driver 110 relative to the workpiece 130.
The polishing pad 180 may be equipped with one or more magnets. For example, still in FIG. 3, the polishing pad 180 may be equipped with four magnets 170, for example. The four magnets 170 may be arranged spreading out as a cross. In another embodiment, in FIG. 4, the polishing pad 180 may have 6 magnets 170, which equally spread close to the periphery of a polymer disk. As an example, the polymer disk can have a diameter of about 60 mm. The magnet 170 may have 12 mm diameter and 3 mm high iron Neodymium magnet. The magnet 170 may fit into about 6 radial slots 410. The radial slots may allow some compliancy in addition to polymer intrinsic stiffness that may be adjusted from totally rigid (aluminum), mid stiff (polyvinyl carbonate, Delrin, polypropylene) to soft (polyurethane, silicone), for example. The polishing pad 180 may be 4 mm thick for a 6 mm thick radial slot, leaving enough room for grinding or polishing paper or polyurethane layer usually stuck to it.
As shown in FIG. 5, the rotatable driver 110 may comprise a driver polishing surface 510 configured to contact an external surface 520 of the workpiece 130 to be polished during rotation of the first polishing surface 122 against the first internal surface 132. In one embodiment, the driver polishing surface 510 may be defined by a non-magnetic polishing driving pad 500. The magnetic coupling may be insured by non-magnetic driving pad 500 involving the corresponding set of magnets 160. These magnets 160 may be advantageously thicker, in order to provide potentially higher coupling forces, or/and larger gap in between pads. In one embodiment, the driving magnets 160 may have about 12 mm diameter, about 6 mm high, for example. Magnets may be secured on polymer pads with bi-component structural adhesives non-sensitive to moisture. Optionally in all embodiments, all magnets on polishing and driving pads may be oriented top north by convention.
Still in FIG. 5, the polisher 100, while shown approximately as wide as the glass sleeve, may be substantially smaller than the glass sleeve. The polisher 100 may be moved about the internal or external surfaces of the sleeve in a random or ordered manner in order to deliver uniform surface finishing, for example.
The polishing tool may further include a second polishing surface 610 axially separated from the first polishing surface 122, as shown in FIG. 6. The second polishing surface 610 may be configured to contact a second internal surface 620 of the workpiece 130 to be polished during rotation of the first polishing surface 122 against the first internal surface 132. The second polishing surface 610 may be defined by a second non-magnetic polishing pad 630. The first and second non-magnetic polishing pad 180 and 620 may be covered by a polishing paper 640. A polishing tool 100 may further include an expander urging the first and second polishing pads apart, such as an internal spring 600, a compressive polymer layer or an expandable polymer that functions as a spring, a pneumatic or hydraulic cylinder and piston, an expandable pneumatic or hydraulic diaphragm or bladder, a telescoping lead screw in a threaded sleeve, a magnetic repulsion provided by magnets with facing north or facing south poles, or any other suitable expansion device, to maintain contact between the first and second polishing surfaces 122 and 620 and the first and second internal surfaces 132 and 620. The expander may help expand the double side polishing pads to polish both internal surfaces of the workpiece.
Optionally in any embodiment, a polishing pad, as shown in FIGS. 5 and 6, may have rounded edges that contact a part or all of the rounded area of the sleeve. Optionally, the rounded edges may mirror the shape of part or all of the rounded area of the sleeve. For example, the polishing pad may have permanently rounded edges. For another example, the rounded edges of the polishing pad may be composed of a sufficiently flexible material to conform to a part or all of the rounded area of the sleeve during polishing.
In another embodiment, a method 700 for polishing a glass sleeve may be carried out as follows, for example. Step 710 is providing a glass sleeve having at least one substantially flat internal surface extending along a longitudinal axis and an internal opening extending along the longitudinal axis, enclosing a space. Step 720 is introducing a rotatable polishing tool comprising a magnetic material, such as a magnetic alloy of neodymium, and a first polishing surface into the space. Step 730 is bringing the first polishing surface into contact with the substantially flat internal surface. Step 740 is introducing a rotatable driver comprising a magnetic material to the exterior of the glass sleeve, wherein at least one of the driver magnetic material and the tool magnetic material is a magnet, such as a neodymium magnet, such that the driver magnetically couples with the polishing tool. Step 750 is rotating the driver, causing the polishing tool to rotate. Optionally in any embodiment, the polishing tool further comprises a second polishing surface axially separated from the first polishing surface. The method further may comprise bringing the second polishing surface into contact with a second substantially flat internal surface of the glass sleeve. Optionally in any embodiment, the driver may further comprise a driver polishing surface. The method 700 may further comprise bringing the driver polishing surface into contact with an external surface of the glass sleeve.
The method 700 may be further carried out by biasing the first and second polishing surfaces axially apart against the first and second substantially flat internal surfaces and mounting at least one of the glass sleeve and the rotatable driver upon a translation stage. The translation stage allows at least one of the workpiece and the polishing tool to be moved generally perpendicular to the axis of rotation, relative to the other of the workpiece and the polishing tool.
In operation, a glass sleeve may be mounted inside a holder, such as a V-shaped holder, and the following grinding sequence can be used, for example.
Grinding paper (600 mesh) may be put on a grinding pad. The glass sleeve may be ground at about 200 rpm, 4×45 mm amplitude during a 2-minute run. The glass sleeve then may be rinsed with water.
Grinding paper (1200 mesh) may then be put on the grinding pad. The glass sleeve may be ground at 200 rpm, at 4×45 mm amplitude during a 4-minute run. The glass sleeve then may be rinsed with water.
Polishing paper having a 9-micron grid may then be put on a polishing pad. The glass sleeve may be polished at 200 rpm, at 4×45 mm amplitude during an 8-minute run. The glass sleeve may be rinsed with water after that.
Polishing paper having a 3-micron grid may be put on the polishing pad. The glass sleeve may be polished at 200 rpm, 4×45 mm amplitude during an 8-minute run. The glass sleeve may be rinsed with water after that.
A polyurethane layer may be put on a finishing pad. The glass sleeve may be polished at 200 rpm at 4×45 mm amplitude during an 8-minute run. The glass sleeve may be rinsed with water after that. After the grinding and polishing have been completed, the internal surface may present flattened topography.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

1. A magnetic polisher comprising:

a. at least one rotatable driver comprising driver magnetic material;

b. at least one rotatable polishing tool comprising tool magnetic material and a first polishing surface;

wherein at least one of the driver magnetic material and the tool magnetic material is a magnet, and the driver and polishing tool are configured to be magnetically coupled with a workpiece having at least a first internal surface to be polished located between the first polishing surface and the driver, such that rotation of the driver about an axis causes rotation of the first polishing surface against the first internal surface.

2. The magnetic polisher of claim 1, wherein at least one magnet comprises a permanent magnet.

3. The magnetic polisher of claim 1, at least one of the driver magnetic material and the tool magnetic material comprises a magnetic neodymium alloy.

4. The magnetic polisher of claim 1, wherein the first polishing surface is defined by a non-magnetic polishing pad.

5. The magnetic polisher of claim 1, wherein the polishing tool further comprises a second polishing surface axially separated from the first polishing surface, wherein the second polishing surface is configured to contact a second internal surface of the workpiece to be polished during rotation of the first polishing surface against the first internal surface.

6. The magnetic polisher of claim 5, wherein the second polishing surface is defined by a non-magnetic polishing pad.

7. The magnetic polisher of claim 5, wherein the polishing tool further comprises an internal spring to maintain contact between the first and second polishing surfaces and the first and second internal surfaces.

8. The magnetic polisher of claim 1, wherein the driver further comprises a driver polishing surface configured to contact an external surface of the workpiece to be polished during rotation of the first polishing surface against the first internal surface.

9. The magnetic polisher of claim 8, wherein the driver polishing surface is defined by a non-magnetic polishing pad.

10. The magnetic polisher of claim 1, further comprising a translation stage upon which either the workpiece or the driver is mounted, wherein the translation stage allows the workpiece to be moved relative to the magnetic polisher generally perpendicular to the rotation axis.

11. The magnetic polisher of claim 1, further comprising a variable spacer configured to adjust and maintain the axial distance between the rotatable driver and the rotatable polishing tool, while the first internal surface is located between the first polishing surface and the driver, to provide the desired normal force between the first polishing surface and the first internal surface.

12. The magnetic polisher of claim 1, in which the driver is configured to remain out of contact with the workpiece when the driver and polishing tool are magnetically coupled and the first polishing surface is rotating against the first internal surface.

13. A method for polishing a glass sleeve comprising:

a. providing a glass sleeve, the glass sleeve having at least one substantially flat internal surface extending along a longitudinal axis and an internal opening extending along the longitudinal axis enclosing a space;

b. introducing a rotatable polishing tool comprising a magnetic material and a first polishing surface into the space;

c. bringing the first polishing surface into contact with the substantially flat internal surface;

d. introducing a rotatable driver comprising a magnetic material to the exterior of the glass sleeve, wherein at least one of the driver magnetic material and the tool magnetic material is a magnet, such that the driver magnetically couples with the polishing tool; and

e. rotating the driver, causing the polishing tool to rotate.

14. The method for polishing of claim 13, wherein the magnet is a neodymium magnet.

15. The method for polishing of claim 13, wherein the magnetic material comprises a magnetic alloy of neodymium.

16. The method for polishing of claim 13, wherein the polishing tool further comprises a second polishing surface axially separated from the first polishing surface, the method further comprising bringing the second polishing surface into contact with a second substantially flat internal surface of the glass sleeve.

17. The method for polishing of claim 16, further comprising biasing the first and second polishing surfaces axially apart against the first and second substantially flat internal surfaces.

18. The method for polishing of claim 1, wherein the driver further comprises a driver polishing surface, the method further comprising bringing the driver polishing surface into contact with an external surface of the glass sleeve.

19. The method for polishing of claim 13, further comprising mounting at least one of the glass sleeve and the rotatable driver upon a translation stage, wherein the translation stage allows at least one of the workpiece and the polishing tool to be moved generally perpendicular to the axis of rotation, relative to the other of the workpiece and the polishing tool.