Patent Grant
10434626
Field of the Disclosure
The following is directed to grinding processes, and more particularly, limiting resonance frequencies during grinding processes
Description of the Related Art
Abrasive wheels are typically used for cutting, abrading, and shaping of various materials, such as stone, metal, glass, plastics, among other materials. Generally, the abrasive wheels can have various phases of materials including abrasive grains, a bonding agent, and some porosity. Depending upon the intended application, the abrasive wheel can have various designs and configurations. For example, for applications directed to the finishing and cutting of metals, some abrasive wheels are fashioned such that they have a particularly thin profile for efficient cutting.
However, in certain operations, the abrasive wheels must be dressed, which is an operation that reconditions the surface of the abrasive article, extending its useful life. In particular, dressing operations can be conducted to remove used abrasive particles and exposes fresh abrasive particles, allowing a user to continue using the abrasive wheel and reducing likelihood of damage to the workpiece. However, dressing operations may cause damage to the abrasive wheel. One of the most prevalent issues with dressing operations is the creation of resonance vibrations in the grinding system. These vibrations can cause variable contact pressure between the wheel and dresser, which subsequently can result in a non-uniform or lobed surface. Such an abrasive wheel surface can adversely affect the quality of a ground part (surface damage, dimensional inaccuracy, or poor tolerances), reduce the life of the abrasive wheel, and even damage the entire grinding system.
Accordingly, the industry continues to demand improved abrasive tools and processes for operating such tools.
According to one aspect, a method of conducting a material removal operation using a grinding system includes moving an abrasive article relative to a workpiece, detecting a change in a dimension of the abrasive article during moving, and reducing resonance vibrations in the grinding system.
According to another aspect, a method of conducting a material removal operation includes removing material from a workpiece using an abrasive article, predicting at least one resonance vibration condition based on at least one process parameter selected from the group consisting of a change in a dimension of the abrasive article, a change in dimension of the workpiece, a change in dimension of the dressing article, an operational rate of the abrasive article, an operational rate of the dressing article, an operational rate of the workpiece, a speed ratio between the abrasive article and dressing article, a speed ratio between the abrasive article and the workpiece, and reducing resonance vibrations in response to the at least one resonance vibration condition.
In yet another aspect, a method of conducting a material removal operation using a grinding system includes removing material from a workpiece using an abrasive article, continuously monitoring a change in diameter of the abrasive article during removing material from the workpiece, and avoiding resonance vibrations in the grinding system during removing material from the workpiece.
For yet another aspect, a method of conducting a material removal operation using a grinding includes removing material from a workpiece using a bonded abrasive, continuously monitoring a change in a diameter of the bonded abrasive during removing material from the workpiece, continuously predicting resonance vibration conditions in the grinding system during removing material from the workpiece, and limiting resonance vibrations in the grinding system based upon the resonance vibration conditions.
The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
The following is directed to grinding systems suitable for shaping workpieces. In particular, the grinding systems can include abrasive articles, dressing articles, workpieces, and a combination thereof as will be described in more detail herein. It will be appreciated that certain components, including for example, motors, spindles, and the like may be considered part of the grinding systems described herein.
The abrasive article 101 can be a component, such as a bonded abrasive article, suitable for abrading and removing material from the workpiece 102. It will be appreciated any variety of grade and structure of bonded abrasive may be utilized depending upon the operation and workpiece material. According to one embodiment, the abrasive article 101 can be a bonded abrasive having abrasive particles contained in a bond material.
The abrasive particles can include a material such as an oxide, carbide, nitride, boride, oxycarbide, oxynitride, boron nitride, diamond, cubic boron nitride, and a combination thereof. In one embodiment, the abrasive particles can include a material having a Vickers hardness of at least about 10 GPa. In other instances, the abrasive particles can have a Vickers hardness of at least about 25 GPa, such as at least about 30 GPa, at least about 40 GPa, at least about 50 GPa, or even at least about 75 GPa. Still, in at least one non-limiting embodiment, the abrasive particles can have a Vickers hardness that is not greater than about 200 GPa, such as not greater than about 150 GPa, or even not greater than about 100 GPa. It will be appreciated that the abrasive particles can have a Vickers hardness within a range between any of the minimum and maximum values noted above.
Furthermore, in one particular embodiment, the abrasive article can include abrasive particles comprising an average particle size of at least about 0.1 microns, such as at least about 1 micron. Still, in other instances, the average particle size of the abrasive particles can be not greater than about 5 mm, such as not greater than about 1 mm. It will be appreciated that the average particle size may be within a range between any of the above minimum and maximum values.
According to at least one aspect, the body of the abrasive article can include at least about 1 vol % abrasive particle for the total volume of the body. In another instances, the body of the abrasive article can include at least about 5 vol %, such as at least about 8 vol %, or even at least about 10 vol % abrasive particles for the total volume of the body. Still, for at least one embodiment, the body can include not greater than about 60 vol % abrasive particles, such as not greater than about 50 vol %, or even not greater than about 40 vol %. It will be appreciated that the content of abrasive particle with the body can be within a range between any of the above minimum and maximum percentages.
The abrasive article may include a bond material made of an inorganic material. Some suitable inorganic materials can include glass, ceramic, metal, metal alloys, and a combination thereof. In other instances, the bond material can include an organic material, and more notably, a polymer or resin, such as a phenolic resin.
Additionally, the abrasive article can include some content of porosity, which may be present through the entire volume of the body of the abrasive article. The porosity may be open porosity, closed porosity, or a combination thereof. In particular instances, the body can have a porosity of at least about 0.1 vol % for the total volume of the body. For yet another embodiment, the porosity can be at least about 1 vol %, such as at least about 5 vol %, or even at least about 10 vol %. In yet another embodiment, the porosity of the body can be not greater than about 70 vol %, such as not greater than about 60 vol %, or even not greater than about 50 vol %. It will be appreciated that the porosity may be within a range between any of the above minimum and maximum percentages.
The abrasive article comprises a body including at least about 1 vol % bond material for the total volume of the body, at least about 5 vol %, at least about 8 vol %, at least about 10 vol %, and not greater than about 75 vol %, not greater than about 65 vol %, not greater than about 60 vol %.
The body of the abrasive article is generally illustrated in
The workpiece can include various materials, including for example, an organic material, an inorganic material, and a combination thereof. In particular instances, the workpiece may include materials such as a metal, a metal alloy, a ceramic, a glass, a composite, abrasives, superabrasives, infiltrated articles, superhard materials, and a combination thereof.
Other abrasive systems are illustrated in
Reference herein to dressing can include dressing or truing operations. Dressing can be conducted to re-sharpen the grinding wheel, removing dull portions (grains and bond) and exposing fresh abrasives and opening the abrasive article. Truing includes re-shaping the wheel to a desired geometry or profile (e.g., round). Truing can remove eccentricities in the profile. Truing, sharpening, opening, and profiling may all occur simultaneously in a dressing process.
While
The dressing article may include abrasive particles contained within a bond material. The abrasive particles can include a superabrasive material, and more particularly may include diamond, and even more particularly may consist essentially of diamond. In certain instances, the abrasive particles of the dressing article may have an average diamond size greater than an average particle size of abrasive particles of the abrasive article.
The dressing article may include a bond material to secure the abrasive particles. According to one embodiment, the bond material of the dressing article can include a ceramic, a glass, a metal (e.g., a metal powder), an organic material (e.g., resin), and a combination thereof (e.g., a hybrid bond). According to one particular embodiment, the bond material of the dressing article can have a hardness greater than the bond material of the abrasive article.
The material removal operation can be conducted by moving the abrasive article relative to the workpiece. For example, the abrasive article may be rotated while the workpiece is held stationary, the workpiece may be rotated while the abrasive article is held stationary, or alternatively, the abrasive article and workpiece may both be rotated relative to each other. In certain operations, the abrasive article may be traversed along a dimension of the workpiece. The abrasive article can be rotated in the same direction as the direction or rotation of the workpiece, or in some instances, in an opposite direction relative to each other.
Moreover, for any of the systems incorporating a dressing article, it will be appreciated that the dressing article can be rotated relative to the abrasive article and/or workpiece in a similar manner as described herein. For example, the dressing article can be rotated while the workpiece and/or abrasive article are held stationary. However, in other instances, the dressing article can be rotated while the abrasive article and workpiece may both be rotated relative to each other. It will be appreciated that the direction of rotation of the dressing article, abrasive article, and workpiece may be the same or different relative to each other.
During the material removal operation, the process can include detecting a change in a dimension of the abrasive article. In at least one embodiment, detecting a change in a dimension of the abrasive article can include detecting a change in any dimension of the abrasive article that may be reduced as a result of conducting the material removal process. For example, the process of detecting a change in the dimension of the abrasive article can include detecting a change in the width or the diameter of the abrasive article. However, it will be appreciated that for other grinding operations, other dimensions of the abrasive article may change depending upon the orientation of the abrasive article relative to the workpiece. The process of detecting a change in a dimension can be conducted using a detection device, such as an optical sensor, mechanical sensor (e.g., accelerometer), mass sensor, force sensor, power sensors, acoustic sensor, and a combination thereof. For example, one or more types of sensors may be used to monitor various parameters of the grinding operation. The output of the accelerometers may be used to measure and/or predict resonance vibrations conditions and further facilitate altering at least one process parameter of the system in response to measured changes to avoid and/or limit resonance vibrations. As such, it will be appreciated that the sensors of the system may be coupled to a computer or data system capable of receiving the input from the sensors, analyzing the input from the sensors, and even adjusting process parameters or suggesting changes to the system to a user.
The width (w) of an abrasive article can be a dimension between two major surfaces in the case of a disk or the dimension extending in an axial direction in the case of a cone or other similar shape. The width of the abrasive article in
Moreover, the process of detecting a change in dimension can be conducted at various times and using various methods. For example, the process of detecting a change in dimension can be conducted simultaneously with the material removal process. Detecting may be completed at intervals wherein the process of removing is not occurring. Alternatively, the process of detecting a change in dimension can be conducted at regular intervals while the process of removing is occurring or at intervals when the process of removing is not occurring. In at least one embodiment, the process of detecting a change of dimension can be conducted continuously throughout the process of removing material.
According to one embodiment, detecting can include measuring a change in the dimension of the body of the abrasive article. Additionally, or alternatively, detecting can include calculating. Calculating may include a process wherein a rate of wear for a particular abrasive article is known, and thus the change in dimension of the body of the abrasive article may be calculated for a certain material removal operation. The foregoing processes may be conducted continuously throughout the material removal processes or alternatively, a distinct interval, which may be regular or irregular intervals as decided by an operator.
According to at least one embodiment, the process can include predicting at least one resonance vibration condition. The method of predicting the at least one resonance vibration condition can be based on one or more process parameters, such as a change in a dimension of the abrasive article, a change in dimension of the workpiece, a change in dimension of the dressing article, a change in the profile of the abrasive article, a change in the profile of the dressing article, an operational rate of the abrasive article, an operational rate of the dressing article, an operational rate of the workpiece, a speed ratio between the abrasive article and dressing article, a speed ratio between the abrasive article and the workpiece. The operational rate can include a rotational rate, which can be measured in revolutions per time, or a linear rate which can be measured in length per time. It will be appreciated that the rotational rate and linear rate can be related by the dimensions of the article (i.e., workpiece, abrasive article, dressing article). The speed ratio can be a ratio of the operating rate of one component relative to another. For example, a first speed ratio [Vw/Vaa] can describe the relationship between the operational rate of the workpiece [Vw] relative to the operational rate of the abrasive article [Vaa]. A second speed ratio can describe a relationship between the operational rate [Vaa] of the abrasive article relative to the operational rate of the dressing article [Vda].
Furthermore, reference herein to a change in a profile of the abrasive article or dressing article can refer to a change in a two-dimensional contour of the article. The contour can be measured along an axial plane, radial plane, and a combination thereof. In particular instances, reference to a change in profile can include a change in the roundness of the abrasive article, which is a dimension extending circumferentially about the outer perimeter of the abrasive article. The profile can be measured and analyzed in light of an intended profile (e.g., the original profile of the abrasive article or a preferred geometric shape). (Is this description adequate to cover the idea of sinusoidally (or otherwise) varying the wheel speed during dressing to vary the speed ratio between dresser and wheel, and thereby the forcing function on the grinding system to avoid chatter during the truing or dressing operation?)
A resonance vibration condition may be an indicia, a numerical value, a range of values, or a range of conditions, which would likely produce a resonance vibration in the grinding system. In one embodiment, the resonance vibration condition can be calculated as a value of operational rate of any or all of the components of the grinding system. In another embodiment, the resonance vibration condition can be calculated as a value of a speed ratio between the abrasive article and workpiece or abrasive article and dressing article. Calculation of the resonance vibration conditions can facilitate prediction of the conditions in the grinding system most likely to cause resonance vibrations and allow a user to limit or avoid the resonance vibration condition.
According to a particular embodiment, the process of predicting at least one resonance vibration condition can be in response to detecting at least one change in at least one dimension of the abrasive article and/or dressing article. Moreover, the process can include calculating at least one resonance vibration condition based on an expected change or a detected change in at least one dimension (e.g., a width, a diameter, and a combination thereof) of the abrasive article or dressing article. The foregoing processes may be conducted continuously throughout the material removal processes, or alternatively, a distinct interval, which may be regular or irregular intervals as decided by an operator.
The process can further include reducing resonance vibrations of the grinding system, which can facilitate improved life of the components in the grinding system and improved results of the material removal process. In particular instances, the process of reducing resonance vibrations can be based upon detecting a change in the dimension of the abrasive article. More particularly, the process of reducing resonance vibrations can be based upon detecting a change in one or more dimensions of the abrasive article, calculating a resonance vibration condition based on the change in the one or more dimensions of the abrasive article, and reducing the resonance vibrations in the system based on the calculated resonance vibration condition. Furthermore, the process of reducing the resonance vibrations can include altering at least one of the process parameters of the grinding system, particularly any of the process parameters being measured or controlled, to facilitate avoiding and/or limiting resonance vibrations in the grinding system.
In one particular embodiment, the process can include measuring a change in diameter of the abrasive wheel during the material removal operation and altering one or a combination of speed ratios of the grinding system, based on the change in the diameter of the abrasive wheel to limit the resonance vibrations in the system.
In another embodiment, the process can include measuring one or more process parameters of the system and avoiding resonance vibrations in the system by continuously altering the speed of one or more components (e.g., the workpiece, the abrasive article, the dressing article). More particularly, the speed may be varied according to a known algorithm, mathematical function of the like. For example, a variation of speed over time may be described by a trigonometric function, such as a sinusoidal curve.
The present application represents a departure from the state of the art. Notably, the embodiments herein disclose a combination of process features suitable for reducing and eliminating resonance vibrations in a grinding system. For example, the present methods include processes including detecting, monitoring, predicting, calculating, reducing, and a combination thereof. Embodiments herein are suited to detect changes in the grinding system during the material removal operation which may create new resonance conditions in the grinding system, and account for such changes and avoid the new resonance conditions. By contrast, conventional approaches do not take into account process parameters of the system and do not predict a resonance vibration condition.
The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
The Abstract of the Disclosure is provided to comply with Patent Law and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description of the Drawings, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description of the Drawings, with each claim standing on its own as defining separately claimed subject matter.
This application is the National Stage of International Application No. PCT/US2013/062288, entitled “Abrasive Article and Method of Forming”, by Christophe Huber et al., filed Sep. 27, 2013, which claims priority to U.S. Patent Application No. 61/706,950, entitled “Abrasive Article and Method of Forming”, by Christophe Huber et al., filed Sep. 28, 2012, which is assigned to the current assignee hereof and incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/062288 | 9/27/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
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| WO2014/052822 | 4/3/2014 | WO | A |
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