Patent Application
20180119286
The present disclosure relates to alloy plating of materials and, more particularly, to method of plating a layer of a material onto a part by using friction burnishing.
Chrome plating is widely used as a surface coating method for metal articles because of its high hardness value, improved durability through abrasion tolerance, superior wear and corrosion resistance, reduced galling or seizing of parts, and increasing chemical inertness. Chrome plating also provides attractive appearance, and sometimes may be further used as bulking material for worn parts to restore their original dimensions. Traditionally, chromium deposition is accomplished by electrodeposition from a chromium plating bath containing chromium ions as a source of chromium. Such processes involve secondary chemicals which are highly toxic in nature and difficult to dispose of. The traditional chrome plating method also consumes a large quantity of water, which is also a by-product of the traditional chrome plating method. Such waste water may, eventually, mix with the used toxic chemicals, thereby affecting the sewage system or, generally, the environment if the toxic water were released.
Thus, industries using chromium plating have to incur additional cost for proper disposal of such toxic waste as per guidelines of Environment Protection Agency (EPA) and other corresponding agencies. Furthermore, the conventional hard chrome plating method will soon be in violation of EU regulations and likely the regulations of other countries, and therefore, it will not be possible to employ this banned conventional chrome plating method for providing chrome plating over desired parts. There are some alternate alloy plating methods but even if other plating processes are not subject to the EU ban, there is nonetheless a need for a simple and non-toxic process for chrome plating that requires limited equipment and materials and that may be customized to yield a wider spectrum of plating results.
While burnishing techniques are known and used in applications for physically or mechanically modifying or burnishing parts, such as in the process of GB822092, such conventional burnishing applications do not achieve a plating effect, such as the one described in the present disclosure. That is, conventional burnishing applications do not involve a substantial transfer of material from the burnishing tool onto a part. In contrast, the present disclosure describes a burnishing application in which, through the application of pressure and speed, particles of the burnishing tool are plated onto the part.
In one aspect of the present disclosure, a plating method for plating a layer of material onto a part is described. The method includes moving the part at a predetermined speed. The method further includes bringing the material into contact with the moving part at a predetermined pressure. The method further includes forming a plating layer of the material on a surface of the part by maintaining the material in contact with the moving part for a predetermined time period.
In another aspect of the present disclosure, a plating method for plating a layer of a first material and a second material onto a part is described. The method includes moving the part at a predetermined speed. The method further includes bringing the first material into contact with the moving part at a predetermined pressure. The method also includes bringing the second material into contact with the moving part at a predetermined pressure. The method further includes forming at least one plating layer of the first material and the second material on a surface of the part by maintaining the first material and the second material in contact with the moving part for a predetermined time period.
In yet another aspect of the present disclosure, a plating method for plating a layer of a material onto a part is described. The method includes moving the part at a predetermined speed. The method further includes bringing the material into contact with a first portion of a circumference of the moving part at a first predetermined pressure. The method also includes bringing the material into contact with a second portion of the circumference of the moving part at a second predetermined pressure. The method further includes forming at least one lobed plating layer of the material on the moving part by maintaining the material in contact with the moving part and switching between the first predetermined pressure and the second predetermined pressure.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, are illustrative of one or more embodiments and, together with the description, explain the embodiments. The accompanying drawings have not necessarily been drawn to scale. Further, any values or dimensions in the accompanying drawings are for illustration purposes only and may or may not represent actual or preferred values or dimensions. Where applicable, some or all select features may not be illustrated to assist in the description and understanding of underlying features.
The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the described subject matter and is not necessarily intended to represent the only embodiment(s). In certain instances, the description includes specific details for the purpose of providing an understanding of the described subject matter. However, it will be apparent to those skilled in the art that embodiments may be practiced without these specific details. In some instances, well-known structures and components may be shown in block diagram form in order to avoid obscuring the concepts of the described subject matter. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.
Any reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, characteristic, operation, or function described in connection with an embodiment is included in at least one embodiment. Thus, any appearance of the phrases “in one embodiment” or “in an embodiment” in the specification is not necessarily referring to the same embodiment. Further, the particular features, structures, characteristics, operations, or functions may be combined in any suitable manner in one or more embodiments, and it is intended that embodiments of the described subject matter can and do cover modifications and variations of the described embodiments.
Generally speaking, a solution involves plating a subject part with a desired alloy material by controlling the pressure, speed and time of burnishing the subject part with the desired alloy material, which results in achieving the desired level of transfer of the desired alloy material onto the surface of the subject part.
Embodiments of the present disclosure generally relate to mechanically plating an part, such as a pin or a cylinder rod, by moving the part and then bringing the moving part into contact with an alloy material containing a high alloy content, such that some of the material having the high alloy content is physically transferred onto the moving part. The amount of the transferred material and the type of bond between the transferred material and the part is dependent upon the speed of movement of the part and the pressure applied between the part and the alloy material, and further upon the time for which the part and the alloy material are in contact with each other. These variables may be selected to achieve various levels of chemical bonding, in light of the desired physical or chemical qualities of the resulting plated part.
In the illustrated example, the part 102 is shown in the form of a cylindrical shaft pin; however the part 102 may have any other suitable shape. For example, the part 102 may have a non-cylindrical shape. In embodiments, the type and direction of movement of the part 102 within the plating process is selected with respect to the shape of the part 102. For example, a part 102 having planar sides may be plated according to an embodiment by moving the part 102 in a back-and-forth motion and bringing each of the planar sides in contact with the alloy material 104 sequentially.
Furthermore, either or both of the part 102 and alloy material 104 may be moved with respect to the other during the burnishing process. That is, in various embodiments, the part 102 may be moved while in contact with the stationary alloy material 104 or the alloy material 104 may be moved while in contact with the stationary part 102. In another embodiment, both the part 102 and alloy material 104 are moved while in contact with each other, in order to facilitate the burnishing process.
In the plating arrangement 100, the part 102 may be mounted on a clamp arrangement 108 of a rotating body (not shown). In one example, as illustrated, the clamp arrangement 108 may be in the form of a chuck. It may be contemplated that the clamp arrangement 108 may use jaws/dogs which may be tightened or loosened to accommodate parts of varying diameters. The rotating body may provide rotational movement to the clamp arrangement 108 and thereby the part 102 when mounted thereon. The rotating body may employ a conventional motor for the purpose of rotating the clamp arrangement 108. Further, the rotating body may be capable of varying the rotational speed of the part 102 to a desired level.
The plating arrangement 100 may also provide a support 110 which may be able to hold the alloy material 104 in place with respect to the part 102. The support 110 may be designed such that at least a portion thereof is movable to enable contact between the outer surface 106 of the part 102 and the alloy material 104, as desired. In one example, as illustrated, the support 110 may be in the form of an arm which may be moved to displace the alloy material 104 to come into contact with the part 102 or removed therefrom. The support 110 may be able to vary the contact pressure between the part 102 and the alloy material 104. Further it may be contemplated that with such arrangement, the support 110 may also be able to vary the time period for which the contact is made between the part 102 and the alloy material 104.
For the purpose of this disclosure, the part 102 may be made of any suitable substrate material capable of supporting a coating of the alloy material 104 thereupon, but is typically a substrate material for which the coating of the alloy material 104 displays sufficient affinity to form a stable coating thereupon. Substrates may be inorganic materials such as metals, or organic materials such as plastics, or composite materials, for example an organic polymer having an inorganic filler. In one example, the substrate is a metal substrate. Non-limiting examples of suitable metal substrates include iron, chromium, nickel, cobalt, copper, aluminum, titanium, and the like. In another example, the substrate includes steel. In yet another example, the substrate includes low alloy steel, for example low alloy carbon steel. In one embodiment, the coating may form a diffusion bond layer between the alloy material and the metal substrate. The formation of such a diffusion bond layer results in coatings possessing advantageous performance characteristics resulting from a strong chemical bond between particles of the substrate and of the coating within the diffusion bond layer.
On the other hand, the alloy material 104 may be chosen based on the requirements of the coating, and further based on the substrate material of the part 102. Many elemental metals and some selected alloys may be used as the alloy material 104. Each material has certain benefits that make its use advantageous in specific applications. One common example of the alloy material 104 to be plated is chromium or nickel, alone, or in combination, for achieving chrome plating of the part 102. As may be understood, it may further be possible to customize the hardness and anti-corrosiveness properties of the resulting plated part 102 by modifying the alloy content of the alloy material 104. In one example, zinc plating may be used to prevent oxidation of the protected metal substrate of the part 102 by forming a barrier and by acting as a sacrificial anode if this barrier is damaged. Another example is zinc-nickel plating which provides excellent corrosion resistance for the part 102. Tin plating is also used extensively to protect both ferrous and nonferrous surfaces, and is particularly useful in the food processing industry since it is non-toxic, ductile and corrosion resistant.
Other commonly deposited materials include copper, boron, solder, brass, cadmium, palladium, silver, gold, etc. For example, by plating steel with boron and applying a heat treatment, a steel and boron alloy is created with high surface hardness. In another example, plating steel with aluminum yields aluminized steel with high corrosion resistance. Further, applying a nitriding heat treatment to such aluminized steel results in a material with high surface hardness. In yet another example, plating steel with copper, zinc, or tin, as the alloy material 104, yields plated part 102 with desirable cosmetic and antimicrobial properties.
In one embodiment, the alloy material 104 includes multiple component materials, which are selectively plated onto the part 102. That is, the alloy material 104 used to burnish the part 102 has a composition different than the alloy material plated onto the part 102. In this embodiment, additional components in the alloy material 104 are used to facilitate plating of the alloy material, but the additional components are not themselves plated onto the part 102. Accordingly, in this embodiment, the composition of the alloy material 104 may not be the same as the composition of alloy material plated onto the part 102.
In one embodiment, controlling the thickness of the coating of the alloy material 104 over the part 102 is generally achieved by varying the speed of the movement of the part 102 and/or the contact pressure between the part 102 and the alloy material 104. It may be contemplated by a person skilled in the art that increasing the speed of the part 102 increases the number of times the outer surface 106 of the part 102 comes in contact with the alloy material 104 for a given time period. Thus, increasing the speed of movement of the part 102 increases the energy input into the transfer of the alloy material 104 to the outer surface 106, and thereby may lead to a thicker coating of the alloy material 104 over the outer surface 106 and may lead to a stronger chemical bond between the alloy material 104 and the outer surface 106. Similarly, increasing the contact pressure between the part 102 and the alloy material 104 adds energy to the transfer of the alloy material 104 to the outer surface 106. Thus, increasing the contact pressure may lead to thicker coating of the alloy material 104 over the outer surface 106 and may lead to a stronger chemical bond between the alloy material 104 and outer surface 106. Also, in one embodiment, the thickness of the coating of the alloy material 104 over the part 102 is controlled by altering the time period the part 102 is in contact with the alloy material 104 while the part 102 is moving. It may be contemplated by a person skilled in the art that the longer the moving part 102 remains in contact with the alloy material 104, more time and energy will be input into the transfer of the alloy material 104 to the part 102, and therefore a thicker coating of the alloy material 104 over the outer surface 106 and a stronger bond therebetween is generated.
Depending upon the selected speed and contact pressure for the alloy plating process, a spectrum of chemical bonding between the part 102 and the alloy material 104 may be achieved. That is, it may be possible to achieve customized parts 102 that vary from mechanically plated with the alloy material 104 to having a diffusion layer of the alloy material 104 to being alloyed with the alloy material 104, based on the speed and the contact pressure (i.e., energy) applied during the alloy plating process. For example, with moderate speed and contact pressure, a small amount of chemical bonding between the alloy material 104 and the outer surface 106 of the part 102 is achieved. In contrast, with high speed and contact pressure, the alloy material 104 may bond by diffusion into the outer surface 106 of the part 102, causing a diffusion gradient of the alloy material 104 to form below the outer surface 106 of the part 102. At very high speed and contact pressure, portions of the outer surface 106 of the part 102 may melt and fuse with the alloy material 104, resulting in a traditional alloying effect at the outer surface 106 between the substrate material of the part 102 and the alloy material 104.
For example, aluminum plating of steel may be done at varying speed and/or contact pressure to achieve aluminized steel with different properties. At moderate speed/pressure, such plating would achieve good corrosion resistance for the part 102. At high speed/pressure, an aluminum-steel alloy may be made which may be subjected to a nitriding heat treatment to achieve a very high surface hardness for the part 102.
In one embodiment, the alloy plating process includes applying the alloy material 104 in multiple passes, using either the same alloy material 104 or different alloy materials 104. This may be done when the desired plating material does not bond well with the part 102 subject to the plating. In this case, an intermediate material may be plated onto the part 102 and then the desired alloy material 104 may be plated onto the intermediate material. Thus with the present process, it may be possible to achieve multiple layers of various materials, such that a layer of an intermediate material may be used to plate an alloy material 104 that does not chemically bond with the material of the part 102. Also, with the alloy plating process of the present disclosure, it may be possible to achieve structural and dimensional modifications of the part 102 by applying the process in multiple passes either simultaneously or sequentially, using different alloy materials 104, and in combination with conventional friction burnishing techniques. If applying two alloy materials 104 simultaneously, a plating layer that is a combination of those materials may be achieved. If applying two alloy materials 104 sequentially, a layer-by-layer structure of different materials on the part 102 may be achieved. Further, different speeds and contact pressures may be applied to the different alloy materials 104, thereby controlling the amount of transfer of each alloy material 104 separately.
Furthermore, the alloy plating process of the present disclosure may also be used to generate a part 102 with a lobed structure, by varying the pressure during the burnishing of the outer surface 106 of the part 102 with the alloy material 104. That is, the alloy plating process may include burnishing a first portion of the outer surface 106 of the part 102 at a first contact pressure and a second portion of the outer surface 106 of the part 102 at a second contact pressure, so that the resulting structure of the plating layer onto the part 102 is lobed.
In one embodiment, the present disclosure relates to a method 200 for plating a layer of the alloy material 104 onto the part 102, as illustrated in the form of a flowchart in
Further, at block 208, the method 200 includes bringing the alloy material 104 in contact with the moving part 102 at a predetermined pressure. In one example, the alloy material 104 may be brought in contact with the moving part 102 by moving the support 110. Further, at block 210, the method 200 includes maintaining the contact between the moving part 102 and the alloy material 104 for a predetermined time period. It may be understood that the predetermined speed, the predetermined pressure, and the predetermined time are selected based on a desired chemical composition and a desired thickness of the plating layer onto the part 102. At block 212, the method 200 optionally includes applying a post-processing treatment to the plated part 102. This post-processing treatment may be applied for achieving the required chemical and physical properties of the part 102 based on its application.
Referring to
At block 306, the method 300 includes moving the part 102 to be plated at a predetermined speed. Further, at block 308, the method 300 includes bringing the first alloy material 104 and the second alloy material 104 into contact with the moving part 102 at a predetermined pressure, either simultaneously or sequentially. Further, at block 310, the method 300 includes maintaining the contact between the moving part 102 and each of the two alloy materials 104 for respective time periods. That is, each of the first and second alloy materials 104 is maintained in contact with the moving part 102 for either the same period of time or for different periods of time. As discussed earlier, if the two alloy materials 104 are applied simultaneously, a plating layer that is a combination of those two alloy materials 104 may be achieved. Alternatively, if the two alloy materials 104 are applied sequentially, i.e., the second alloy material 104 is brought into contact with the moving part 102 when the first alloy material 104 is not in contact with the part 102, a layer-by-layer structure of different materials on the part 102 may be achieved.
Referring to
Further, at block 408, the method 400 includes bringing the alloy material 104 in contact with the moving part 102 intermittently at a predetermined pressure, such that a same region of the part 102 is in contact with the moving part 102 during each rotation cycle. It may be contemplated by a person skilled in the art that this intermittent contact/engagement of the alloy material 104 with the part 102 may be achieved by using a timing mechanism in the support 110, so that when the part 102 is moving at a constant speed, the support 110 may move at regular intervals of time to enable contact of the alloy material 104 and the part 102. Further, at block 410, the method 400 includes brining the alloy material 104 into contact with the moving part 102 for a predetermined time period. It may be understood that the intermittent intervals and the time period may be determined based on the desired lobe structure for the part 102.
In yet another embodiment, the present disclosure provides a method 500 to generate at least one lobed plating layer of the alloy material 104 onto the part 102, as illustrated in the form of a flowchart in
The genesis of the alloy plating process of the present disclosure was the need for a novel chrome plating method because the conventional chrome plating method involves secondary chemicals that are toxic and, therefore, the conventional chrome plating method will soon be banned in some jurisdictions. In order to achieve chrome plating via a different method, the alloy plating process of the present disclosure includes mechanically burnishing the part subjected to the plating with the alloy material to be plated (i.e., chromium, nickel, etc.), such that some amount of the alloy material is transferred onto the part. While burnishing techniques are well known in the art, such techniques were traditionally directed to polishing one surface using another, and not for transferring material from one surface onto the surface of another part to achieve a plating effect.
The alloy plating process of the present disclosure may extend to various parts to be plated and to various alloy materials. That is, parts of different of compositions may be plated with various alloy materials using the present process. Depending on the composition of the part, the alloy material to be plated onto the part, and the amount of material transfer required for achieving the desired plating, a rotation speed and a contact pressure may be selected for the burnishing process. Also, the time period or duration of the burnishing may be appropriately selected. Conventional techniques do not include any process for using mechanical or friction burnishing to achieve a desired level of transfer of material onto a part, such that the speed and pressure of the burnishing cause the desired level of transfer/plating.
Embodiments of the present disclosure for coating the alloy material 104 over the part 102 may be applied for alloy plating of various types of parts 102. The alloy plating process of the present disclosure is particularly applicable for parts 102 with cylindrical shapes. Examples of parts 102 subject to the alloy plating process of the present disclosure are steel pins and shafts. However, other shapes may also be subject to the present process, using either rotation or oscillation of the part 102 with respect to the alloy material 104. The parts 102 to be coated by the present method may be a metal part made of, for instance, steel, copper, bronze, brass, etc., or it may be a part made of ceramics or plastics. For example, the methods of the present disclosure may be utilized for providing alloy plating to various components of a fuel injection assembly of a diesel engine, such as, but not limited to, a plunger or a poppet valve.
The alloy plating process of the present disclosure achieves plating by burnishing chrome and/or nickel without use of the toxic chemicals as employed in conventional hard chrome plating method. One advantage of the present process is that different levels of bonding/plating may be achieved, from mere mechanical bonding to alloying by controlling the speed and pressure of the burnishing process. For example, the present process achieves corrosion resistance for the part 102 by achieving a small amount of chemical bonding between the part 102 and the applied alloy material 104 by applying moderate speed and pressure between the part 102 and the alloy material 104. Further, the present process may be employed to generate a diffusion gradient of the alloy material 104 on the outer surface 106 of the part 102, with application of higher speeds and pressures between the part 102 and the alloy material 104. Furthermore, the present process may be employed to generate a lobe structure for the part 102, which may be advantageous because the lobe may then be ground down such that a portion of the outer surface 106 may have the alloy material 104 and another portion of the outer surface 106 may be the substrate material of the part 102. Therefore, after machining the lobed part 102, there is a variation in the material being worn as the part 102 rotates during operation, which in turn may reduce wear and galling of the part 102.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
