EP3356581A1

EP3356581A1 - Anodization involving a lubricant

Info

Publication number: EP3356581A1
Application number: EP16889590.2A
Authority: EP
Inventors: Cheng-Feng Liao; Kuan-Ting Wu; Weiming TSENG; Hsin-Chien Chu
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2016-02-03
Filing date: 2016-02-03
Publication date: 2018-08-08
Also published as: EP3356581A4; CN108291324A; WO2017135939A1; US20180327925A1

Abstract

One example provides a method. The method includes etching a portion of a substrate to create a plurality of cavities, the substrate including a metal-containing material. The method includes disposing a resin over the portion, including filling at least some of the plurality of cavities with the resin. The method includes anodizing the substrate, including the portion. The method includes disposing a hydrocarbon lubricant over the anodized substrate.

Description

ANODIZATION INVOLVING A LUBRICANT BACKGROUND

[0001] The housing/casing of electronic devices, particularly those of portable electronic devices, is frequently subject to environmental corrosion, and thus the structural components of the housing in some examples are processed to have properties to withstand such corrosion. At the same time, the aesthetic of these structural components may be important, particularly with respect to attracting users to use the electronic devices of which the housing is a part.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The drawings are provided to illustrate various examples of the subject matter described herein related to methods of anodization involving a lubricant and are not intended to limit the scope of the subject matter. The drawings are not necessarily to scale.

[0003] Fig. 1 shows a flowchart illustrating one example of a method described herein.

[0004] Fig. 2 shows a flowchart illustrating another example of a method described herein.

[0005] Fig. 3 shows a flowchart illustrating another example of a method described herein.

DETAILED DESCRIPTION

[0006] Anodization is a process often employed to process a metal-containing substrate to achieve certain desirable properties. In some examples, anodization is employed for processing a metal-containing substrate during manufacturing of the housing structural components of an electronic device. In at least some examples, some of these housing components contain a polymer layer (e.g., plastic layer) over at least a portion of the metal-containing substrate. For example, in at least one example, the metal-containing substrate may contain a slot antenna, which is covered with a polymer (e.g., resin). In one example, a slot antenna is employed because it may be cut out of any surface it is to be mounted on, and may have radiation patterns that are roughly omnidirectional (similar to a linear wire antenna). Slot antennas may be employed at frequencies between 300 MHz and 24 GHz - but other frequency ranges are also possible. However, upon completion of anodizing the substrate (with the metal portion and the polymer portion), it has been observed that anodization in at least some instances may result in discoloration of these polymer portion in the final product, adversely affecting the cosmetic

appearance of the final product.

[0007] In view of the aforementioned challenges related to the anodization of the structural components of an electronic device, the Inventors have

recognized and appreciated the advantages of an anodization process involving a lubricant. Following below are more detailed descriptions of various examples related to an anodization process, particularly one involving using a lubricant. In one example, the process involves applying a lubricant on the slot antenna plastic over a metal-containing substrate; thereafter the plastic portion (of the slot antenna) and the metal-containing portion are both anodized. The various examples described herein may be implemented in any of numerous ways.

[0008] Provided in one aspect is a method comprising: etching a portion of a substrate to create a plurality of cavities, the substrate comprising a metal- containing material; disposing a resin over the portion, including filling at least some of the plurality of cavities with the resin; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate.

[0009] Provided in another aspect is a method comprising: forming a substrate using computer controlled machining, the substrate comprising a metal-containing material; etching a portion of the substrate to create a plurality of cavities; disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate. [0010] Provided in another aspect is a method comprising: forming a substrate using computer controlled machining, the substrate comprising a metal-containing material; etching a portion of the substrate to create a plurality of cavities; disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin; processing the substrate, including the portion, using computer controlled machining; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate.

[0011] The indefinite articles "a" and "an," as used herein in this disclosure, including the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0012] The terms "substantially" and "about" used throughout this disclosure, including the claims, are used to describe and account for small fluctuations. For example, they may refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1 %, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1 %, such as less than or equal to ±0.05%.

[0013] Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. Such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of "1 weight % (wt%) to 5 wt%" should be interpreted to include not only the explicitly recited values of 1 wt% to 5 wt%, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values, such as 2, 3.5, and 4, and sub-ranges, such as from 1 -3, from 2-4, and from 3-5, etc. This same principle applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. [0014] Fig. 1 describes the processes involved in one example of a method described herein. The method may comprise etching a portion of a substrate to create a plurality of cavities, the substrate comprising a metal-containing material (S101 ).

[0015] The term "metal-containing material" here may refer to a material that contains an observable amount of metal. Depending on the application, any suitable material may be employed in the methods of manufacturing described herein. The "metal" in the metal-containing material (of the substrate) may comprise a pure metal, a metal alloy, an intermetallic, a metallic compound, or a metal-containing composite. Note that the substrate may comprise one single layer of the metal material or may comprise multiple layers of the same of different materials, at least some of which is the metal material. The metal may comprise at least one of aluminum, iron, magnesium, copper, titanium, and an alloy of any of the foregoing. In one example, an iron-containing metal material is steel, such as stainless steel. In one example, the metal material comprises magnesium or an alloy thereof. In one example, the metal material is a magnesium alloy. The metal material may comprise an alloy of any of the aforementioned metal elements or a combination of any of the aforementioned metal elements.

[0016] An "observable amount" herein may refer to between about 30 wt% and about 100 wt% - e.g., between about 40 wt% and about 90 wt% , between about 50 wt% and about 80 wt%, between about 60 wt% and about 70 wt%, etc. Other content values are also possible. A metal-containing material may comprise the metal uniformly or non-uniformly throughout the material.

[0017] The etching may involve any type of chemical etching. The type of etchant and etching condition need not be of any particular type and may vary depending on the materials involved and the desired results to be achieved.

[0018] The method as described in Fig. 1 may further comprise disposing a resin over the portion, including filling at least some of the plurality of cavities with the resin (S102). The disposing process may comprise molding, such as insert molding, of the resin over the aforementioned portion of the substrate. In one example, insert molding refers to a process of molding or forming plastic parts around other, non-plastic parts, or inserts. In one example, the insert molding involves nano-molding technology ("NMT").

[0019] In one example where NMT is used, after chemical etching, the metal- containing substrate is rinsed with water and then immersed in ammonia, hydrazine or a water-soluble amine compound, followed by water rinsing and drying. A ferrous material shaped article appropriate for injection joining can be obtained thereby. The immersion in a dilute aqueous solution of ammonia, hydrazine or a water-soluble amine compound may enhance at least

characteristics relating to injection joining. The condition of the disposing process may vary, depending on the materials involved. For example, in one example wherein the disposing process involves insert molding, the molding temperature, such as that of the mold, may be about 100 °C and about 200 °C - e.g., between about 1 10 °C and about 180 °C, between about 120 °C and about 160 °C, between about 130 °C and about 150 °C, etc. Other values are also possible. In one example, the molding temperature is about 140 °C.

[0020] Further, additional processes may be involved. For example, in one example, before the molding process takes place, during the disposing process a pre-drying process may be employed. The pre-drying process may take place at any suitable temperature for any suitable length of time. For example, the drying may take place at 130 °C for three hours. Other values are also possible.

[0021] The cavities may have any suitable geometries, including shapes and sizes. For example, these cavities may have a through-thickness, such that the underlying substrate is exposed through the cavities to the ambiance. The cavities may also not have through thickness. The cavities may have cylindrical shape, or any other suitable shape.

[0022] The resin to be disposed over the substrate may comprise any suitable polymer. The polymer may be any of those that may withstand the conditions of anodization later applied to the substrate - as further described below in (S103). For example, the resin may comprise at least one of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), and ABS/PC. Other polymers may be employed.

[0023] The resin may further comprise fibers, such as glass fibers. The amount of glass fibers in the resin need not be of any particular value. For example, the resin may comprise between about 10 and about 60 wt% of glass fibers - e.g., between about 15 and about 50 wt% of glass fibers, between about 20 and about 40 wt% of glass fibers, between about 25 and about 30 wt% of glass fibers, etc. Other values are also possible.

[0024] In one example, the resin comprises PBT and about 25 wt % glass fibers. In another example, the resin comprises PBT and about 30 wt% glass fibers. In another example, the resin comprises PBT and about 40 wt% glass fibers. In another example, the resin comprises PPS and about 15 wt% glass fibers. In another example, the resin comprises PPS and about 40 wt% glass fibers.

[0025] The method as described in Fig. 1 may further comprise anodizing the substrate, including the portion (S103). Anodization may refer to

an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. In one example, the part to be treated may form the anode electrode of an electrical circuit. Anodizing may increase resistance to corrosion and wear, and provide better adhesion for paint primers and glues than may bare metal. Anodic films may also be used for a number of cosmetic effects, either with thick porous coatings that may absorb dyes or with thin transparent coatings that add interference effects to reflected light. The type of reagent and anodization conditions need not be of any particular type or value and may vary depending on the materials involved and the desired results to be achieved.

[0026] The method as described in Fig. 1 may further comprise disposing a hydrocarbon lubricant over the anodized substrate (S104). The lubricant may have any suitable properties. For example, any material that may reduce the surface roughness of the substrate (e.g., by filling some of the cavities on the surface) may be considered a lubricant. For example, the lubricant may have a desirable level of viscosity, although the value of the viscosity may vary depending on the materials and result desired to be achieved. In one example, the hydrocarbon lubricant may have a viscosity of between about 50,000 cps and about 80,000 cps - e.g., between about 60,000 cps and about 70,000 cps. Other values are also possible. In one example, the viscosity is about 64,000 cps.

[0027] The hydrocarbon lubricant may comprise any suitable material that may provide lubrication for the surface of the anodized substrate. The hydrocarbon lubricant may comprise at least one of a processing oil, a wax, a mineral oil, a vegetable oil, a hydrogenated polyolefin, an ester, a silicone, a fluorocarbon, and a petroleum jelly. In one example, the hydrocarbon lubricant comprises a petroleum jelly - e.g., Vaseline™. In some examples, the lubricant may additionally comprise additives, such as fillers. The additives may be an organic material or an inorganic material. The additive fillers may be nano pigments, dyes, or a combination thereof. For example, the filler may be a ceramic.

Examples of a suitable filler may include carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, an organic powder, an inorganic powder, graphene, graphite, and dispersed elastomers. Other types of suitable materials may also be employed.

[0028] The hydrocarbon lubricant disposed over the anodized substrate may have any suitable thickness value. For example, the lubricant may have a thickness of between about 1 pm and about 50 pm - e.g., between about 10 pm and about 40 pm, between about 20 pm and about 30 pm, etc. Other values are also possible. In one example, the thickness is between about 10 pm and about 20 pm. In one example, to achieve relatively uniform thickness of the lubricant over the substrate, a scraping across the surface after the lubricant is disposed over the substrate may be employed to remove any excess, or non- uniformity of, the lubricant disposed over the anodized substrate. [0029] As a result of the application of the hydrocarbon lubricant over the substrate, the (lubricated) substrate may have a significant smaller surface roughness than an anodized substrate without the lubricant. The surface roughness may be characterized with any suitable parameters. For example, the surface roughness may be described using Rz, which denotes an average distance between the highest peak and lowest valley in each sampling length. The surface roughness may also be described using Ra, which denotes an arithmetic average of absolute values. The roughness may be obtained using any standard techniques, such as standard IS04287. In one example, the Rz of the lubricated substrate surface may be less than or equal to about 15 pm - e.g., less than or equal to about 10 pm, about 8 pm, about 6 pm, about 4 pm, about 2 pm, or smaller. Other values are also possible. In one example, the Ra of the lubricated substrate surface may be less than or equal to about 2 pm - e.g., less than or equal to about 1.5 pm, about 1 .0 pm, about 0.8 pm, about 0.6 pm, about 0.4 pm, about 0.2 pm, or smaller. Other values are also possible.

[0030] In one non-limiting working Example, the Inventors observed that the substrate after anodization but prior to the application of the lubricant, the surface roughness Rz of the anodized substrate was 17.87 pm, and Ra of the anodized substrate was 2.47 pm. The roughness was measured using an Olympus OLS4100 Laser Confocal Microscope. In contrast, after the

hydrocarbon lubricant was applied to the substrate, the surface roughness Rz of the substrate was 1 .62 pm, and Ra of the substrate was 0.28 pm. The enhancement in surface roughness (reduction) was prominent even after the samples were tested in an accelerated environmental life test at a constant temperature at 60 °C and a relative humidity of 95% for 70 hours. Specifically, the Inventors observed that after the hydrocarbon lubricant was applied to the substrate, the surface roughness Rz of the substrate was 4.32 pm, and Ra of the substrate was 0.85 pm. It was noted that even though the roughness increased a little as a result of the test, the roughness values Rz and Ra were still both smaller than those of the original sample. [0031] Fig. 2 is a flow chart illustrating another example of the methods described herein. It is noted that any of the components described in Fig. 2 may be any of those described here in this disclosure. The method may comprise forming a substrate using computer controlled machining, the substrate comprising a metal-containing material (S201 ). Depending on the application, the methods of forming/manufacturing described herein may involve various processes as a part of, or other than, those described herein. In one example, the substrate is formed by any suitable method, such as one involving at least one of computer numerical control machining ("CNC") (e.g., computer controlled cutting) and forging. The parameters of the processes may vary depending on the materials and processes involved.

[0032] The method may further comprise etching a portion of the substrate to create a plurality of cavities (S202). Etching may be any of those described herein. The method may further comprise disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin (S203). The resin may be any of those described herein. The method may further comprise anodizing the substrate, including the portion. The method may further comprise disposing a hydrocarbon lubricant over the anodized substrate (S204). The hydrocarbon lubricant may be any of those described herein.

[0033] Fig. 3 is a flow chart illustrating another example of the methods described herein. The method may comprise forming a substrate using computer controlled machining, the substrate comprising a metal-containing material (S301 ). The formation of the substrate may involve CNC. The method may comprise etching a portion of the substrate to create a plurality of cavities (S302). Etching may be any of those described herein. The method may comprise disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin (S303). The resin may be any of those described herein.

[0034] The method may comprise processing the substrate, including the portion, using computer controlled machining (S304). The additional processing herein may refer to trimming the substrate or the resin overflow. The trimming may involve any suitable techniques, including, for example, CNC. The method may comprise anodizing the substrate, including the portion (S305). The method may comprise disposing a hydrocarbon lubricant over the anodized substrate (S306). The hydrocarbon lubricant may be any of those described herein. It is noted that any of the components described in Fig. 3 may be any of those described here in this disclosure.

[0035] The methods of manufacturing described herein may further comprise inspection of the product after a particular process. An inspection may involve any quality control process. An inspection process may be applied after any of the processes described herein is completed. In one example, an inspection process is employed for the substrate after at least one of the cutting (e.g., diamond cutting) and disposing processes.

[0036] The equipment that may be employed for the manufacturing methods described herein is not limited. As long as the equipment may perform the processes as described herein, the equipment may be used.

[0037] The methods of manufacturing described herein may comprise additional processes. For example, the machining, such as CNC, may be employed in any of the processes described herein. For example, the methods described herein may additionally comprise forming an electronic device comprising the anodized substrate having the hydrocarbon lubricant disposed thereover. The lubricated substrate may be a part of the housing of the electronic device. The part may be one comprising a slot antenna.

[0038] Due at least in part to the numerous aforedescribed desirable properties, the housing structure described herein may be employed in various applications. For example, the housing structure may be an integral part of a structural component. The component may be a part of the housing of an electronic device. A housing of a device may refer to any structural component that encloses the interior of the device. In one example, the housing structure described herein is a part of the housing of an electronic device. For example, the housing structure may be any part of the housing, including back cover, front cover, side cover, and the like, of the device.

[0039] An electronic device herein may refer to any device comprising at least one electrical circuit. Thus, in one example, the housing that comprises the housing structure described herein may be external to the electrical circuit. The electronic device may be a consumer electronic device. An electronic device may refer to portable/mobile electronic device. An electronic device herein may refer to a computer, a memory storage, a display, a signal transmitting device, and the like. A computer may refer to a desktop, a laptop, a tablet, a phablet, a tablone, and the like. A storage unit may refer to the hardware of a hard drive, a server, a processor, and the like. A display may refer to a monitor, a liquid crystal display ("LCD"), a television, and the like. A signal transmitting device may refer to a device transmitting any type of signal, including light, sound, heat, and the like. In one example, the electronic device is a mobile phone.

[0040] Not to be bound by any particular theory, but due at least in part to the methods and structures described herein, the methods of manufacturing described herein may have beneficial properties. For example, the methods herein may resolve the discoloration issue on slot antenna plastic surface after anodizing; improve cosmetic surface quality; increase production yield rate; and have a short production cycle time.

[0041] It should be appreciated that all combinations of the foregoing concepts (provided such concepts are not mutually inconsistent) are

contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein. [0042] In this disclosure, including the claims, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, § 21 1 1 .03.

Claims

WHAT IS CLAIMED:

1 . A method comprising: etching a portion of a substrate to create a plurality of cavities, the substrate comprising a metal-containing material; disposing a resin over the portion, including filling at least some of the plurality of cavities with the resin; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate.

2. The method of claim 1 , wherein disposing the resin comprises insert molding of the resin over the portion.

3. The method of claim 1 , wherein the substrate comprises at least one of aluminum, iron, magnesium, copper, titanium, and an alloy of any of the foregoing.

4. The method of claim 1 , wherein resin comprises at least one of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), and ABS/PC.

5 The method of claim 1 , wherein the resin comprises between about 15 and about 50 wt% of glass fiber.

6. The method of claim 1 , wherein the hydrocarbon lubricant comprises at least one of a processing oil, a wax, a mineral oil, a vegetable oil, a hydrogenated polyolefin, an ester, a silicone, a fluorocarbon, and petroleum jelly.

7. The method of claim 1 , wherein the hydrocarbon lubricant comprises a petroleum jelly.

8. A method comprising: forming a substrate using computer controlled machining, the substrate comprising a metal-containing material; etching a portion of the substrate to create a plurality of cavities; disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate.

9. The method of claim 8, wherein disposing the resin comprises insert molding at a molding temperature of between about 130 °C and about 150 °C.

10. The method of claim 8, wherein the hydrocarbon lubricant disposed over the anodized substrate has a thickness of between about 10 pm and about 20 pm.

1 1 . The method of claim 8, wherein the hydrocarbon lubricant has a viscosity of between about 60,000 cps and about 70,000 cps.

12. The method of claim 8, wherein the hydrocarbon lubricant comprises nano pigments, dyes, or a combination thereof.

13. The method of claim 8, further comprising forming an electronic device comprising the anodized substrate having the hydrocarbon lubricant disposed thereover.

14. A method comprising: forming a substrate using computer controlled machining, the substrate comprising a metal-containing material; etching a portion of the substrate to create a plurality of cavities; disposing a resin comprising glass fibers over the portion, including filling at least some of the plurality of cavities with the resin; processing the substrate, including the portion, using computer controlled machining; anodizing the substrate, including the portion; and disposing a hydrocarbon lubricant over the anodized substrate.

15. The method of claim 14, wherein the anodized substrate having the hydrocarbon lubricant disposed thereover has at least one of the following: an Rz of less than or equal to about 2 pm; and an Ra of less than or equal to about 1 pm.