The invention relates to methods and assemblies for polishing optical cables.
Fiber optic cables are cables that contain several thousand optical fibers in a protective insulated jacket. These optical fibers are very thin strands of silica (e.g., glass) that transmit information in the form of light. Fiber optic cables are increasingly used in industries such as telecommunications, medical diagnostics, medical therapeutics (e.g. surgery and dentistry), automotive, lighting, mechanical inspection and analytical instrumentation, military, and aerospace.
Fiber optic cables are polished after cleaving to remove scratches and other surface imperfections that promote signal loss. Typically, fiber optic cable polishers include a cable mount and a rotating polishing film that presses and rubs against the cable. Among the important factors for consideration to achieve high precision polishing include the speed of the rotating film, the positioning of the cable and its applied pressure against the rotating film, and the duration of polishing.
The invention provides improved methods, assemblies and devices for high precision polishing, which can be adjusted in a reactive manner due to inputs in real time from physical force data. This is achieved in one aspect of the invention by a method of polishing optical cables, which includes a polishing assembly loaded with a polishing film, the polishing assembly having a platform to which the polishing film is loaded, the platform configured to rotate according to a dual orbital motion and coupled to a force gauge that measures downward force applied against the platform, a mounting fixture configured to mount a plurality of optical cables, the mounting fixture attached to a movable arm that moves the mounting fixture towards and away from the platform. The method includes mounting a plurality of optical cables to the mounting fixture; pressing the optical cables against the rotating polishing film while simultaneously monitoring the downward force applied against the platform; and adjusting the downward force to remain within a prescribed tolerance.
In some embodiments, the fixture includes a plurality of clamps that clamp the plurality of optical cables in place. In further embodiments, the clamps include a moveable tab that locks closed using magnetic force.
In preferred embodiments, the fixture and platform are adjustably aligned parallel to one another, preferably by way of adjustment dials that adjust the fixture and platform. In some embodiments, the adjustment dials are 4-way adjustment dials.
The rotation speed of the platform preferably increases gradually. Likewise, the arm presses the cables against the rotating polishing film gradually to polish the cables at a lower pressure followed by polishing the cables at a higher pressure. The higher pressure can vary but is typically about 0.5-1 lb. of pressure per cable.
In preferred embodiments, the force gauge is in physical-force communication with the platform, thereby measuring pressure directly applied to the platform. This downward force can be adjusted by a feedback mechanism that functionally couples the force gauge to the arm.
The method can also include washing the polished optical cables in an ultrasonic bath, the bath optionally filled with deionized water and/or isopropyl alcohol. Moreover, the method can include optically inspecting a polished surface of the cables, and optionally repeating polishing and washing steps until the polished surface meets a final acceptable standard. During such a process a same or different polishing film can be used. The preferred approach for optical inspection includes inspection by camera. The camera may be configured to relay inspection footage to a computer, loaded with software that compares the polish to an intermediate or final standard. In some embodiments, the camera provides a live feed to a computer.
In a related aspect of the invention, a polishing assembly is provided, which includes a platform configured to receive a polishing film and configured to rotate according to a dual orbital motion; a force gauge functionally coupled to the platform and configured to measure downward force applied against the platform; a mounting fixture configured to mount a plurality of optical cables; and a movable arm configured to move the mounting fixture downwards to press mounted cables against the polishing film, upwards to pull the mounted cables away from the polishing film, and to rotate circularly along a continuous circular path.
The fixture can include a plurality of clamps that clamp the plurality of optical cables in place. The clamps can include a moveable tab that locks closed using magnetic force.
In some embodiments, the fixture and platform are adjustably aligned parallel to one another, preferably by way of adjustment dials that adjust the fixture and platform, the adjustment dials optionally being 4-way adjustment dials.
Preferably, the force gauge is in physical-force communication with the platform, thereby measuring pressure directly applied to the platform. The force gauge can communicate directly with the arm or with a computer that communicates with the arm.
The polishing assembly can also include or be used in connection with an ultrasonic bath, the bath optionally filled with deionized water and/or isopropyl alcohol. The polishing assembly can also include or be used in connection with an optical inspection station, which includes a camera. The camera can relay inspection footage to a computer, optionally loaded with software that compares the polish to an intermediate or final standard. In some embodiments, the camera provides a live feed to a computer.
In still another related aspect of the invention, a mounting fixture configured to mount a plurality of optical cables is provided, which includes a planar surface having a plurality of apertures for receiving a plurality of optical cables; a plurality of arms that rock open and closed to release and lock the cables in place; and a plurality of magnets that magnetically lock the arms closed.
Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.
In accordance with various embodiments herein, a polishing assembly and methods of polishing optical cables are disclosed here. More specifically, the polishing assembly may polish optical cables at a high precision, thereby, reducing signal loss when coupling ends of the optical cables to connectors or other devices.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustrative embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and mechanical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof. For completeness, the invention is discussed with respect to an “optical cable”, which is intended to encompass a fiber optic strand and a group of fiber optic strands as known in the fiber optic industry. However, the polishing assembly will also have use with other industries, where a high-precision polish of a silica substrate is desired.
Referring now to the drawings,
In one or more embodiments, arm 16 may move in one or more directions to achieve various positions relative to platform 12. In one or more embodiments, arm 16 may be moved to any desired position using, for example, dials 38. In one or more embodiments, arm 16 may move mounting fixture 50 towards platform 12 and corresponding polishing film 80 (shown in
By “mounted”, it is meant that cables 70 traverse mounting fixture 50 by passing through pad 46 and are held in place. For example, cables 70 traverse through an aperture 52 of pad 46 and are held in place such as by way of a clamp 54. In one or more embodiments, each clamp 54 may include at least a tab 56, a spring 60, and at least two magnets 58 (e.g., magnet 58a of tab 56 and magnet 58b of pad 46). In such embodiments, each clamp 54 has at least two positions, namely, an open position (shown in
Although there are different mechanisms available to the skilled artisan to reversibly clamp cables 70,
Turning to
Proceeding to
In some embodiments, force gauge 20 communicates directly with electronic circuitry in arm 16 to instruct upward or downward movement of arm 16 to achieve a desired force. In other embodiments, force gauge 20 collects pressure readings and provides the data to a computer processing unit, which instructs movement of mechanical arm 16 and, optionally, rotational speed of polishing platform 12 in response to the provided pressure data. To this end, the dual orbital speed of polishing platform 12 and the contact force of cables 70/mounting fixture 50 can be adjusted in response to pressure data provided by force gauge 20. In other embodiments, force gauge 20 provides data to ensure surface 82 of mounting fixture 50 is level with surface 84 of platform 12 so that pressure is evenly applied to each cable 70. Furthermore, the computer processing unit may use an algorithm that compensates for nonlinearity and to prevent any undesired play or wiggle in arm 16 and mounting fixture 50 when not in use, which is often an inherent problem in stepper motors. In one or more embodiments, the computer processing unit may also determine the lifetime of polishing film 80. For example, a timer of the computer processing unit may count the number of polishing cycles, the time of each polishing cycle, and/or the pressure of each polishing cycle to determine when a user should replace polishing film 80. As understood by one skilled in the art, the computer processing unit may be any compatible electronic device (e.g., processor, smartphone, desktop computer, laptop, or tablet). In one or more embodiments, computer processing unit may be loaded with a software (e.g., an application). In one or more embodiments, computer processing unit may include an interface that allows for user input or display of collected or processed data.
The technical approach of coupling a force gauge 20 to the platform 12 rather than measuring an applied force through or at the arm 16 has many advantages. For example, a system that measures force at the arm 16 requires substantially more compensation in that the measurement would also have to consider the weight of the fixture 50, any connectors, optical cables 70 mounted to the fixture 50, and arm 16 itself. Furthermore, it would also have to compensate for the downward force being applied by the arm 16 itself during polishing.
As already introduced, the feedback mechanism controls the movement of arm 16 and, thus, the pressure applied from cables 70 against polishing platform 12. This feedback mechanism can be by directly communicating force gauge 20 to a regulator that regulates downward movement of arm 16. The regulator can be programmed to perform a stepwise progression through a preset array of pressures or can be adjusted manually by a user to perform a desired pressure. In other embodiments, force gauge 20 is communicatively coupled to a computer with programming able to receive the pressure data and, in response, adjust movement of fixture 50 towards polishing platform 12 to meet program requirements. Preferably, the computer is also communicatively coupled to motor 92 of polishing assembly 10 for controlling the speed of the dual orbital rotation of polishing platform 12 so that the rotational speed of polishing film 80 can progress according to real time measurements of the applied pressure.
In exemplary embodiments, cables 70 mounted within apertures 52 of outer arrangement 172 may follow along outer path 32 of cable path 22 during the polishing process, and cables 70 mounted within apertures 52 of inner arrangement 174 may simultaneously follow along inner path 34 of cable path 22 during the polishing process (shown in
In one or more embodiments, polishing assembly 10 includes or is used together with an ultrasonic bath (not shown). For example, arm 16 of polishing assembly 10 may pivot about axis B toward a washing station 310. Washing station 310 may include an ultrasonic bath 306. Ultrasonic baths are liquid baths that use cavitation bubbles induced by high frequency to agitate the liquid. This agitation produces high forces on contaminants adhering to substrates, such as optical cables 70. Accordingly, the method of polishing optical cables 70 can also include movement of arm 16 to move cables 70 away from platform 12, rotation towards ultrasonic bath 306, and lowering optical cables 70 into ultrasonic bath 306 to remove residual material away from optical cable 70. Though non-limiting, ultrasonic bath 306 can include deionized water, isopropyl alcohol, or any combinations thereof.
In one or more embodiments, polishing assembly 10 may also include or be used together with an inspection station 320. Inspection station 320 may include a camera 304, which is in communication with electronic device 302 via communication link 312. Communication link 312 may be a wired or wireless communication link. For example, wired communication may be but not limited to, Ethernet, DSL, or cable. Wireless communication may be, but not limited to, use Bluetooth or Wi-Fi. Inspection station 320 may be used to inspect the surfaces of cables 70 before, during, or after polishing station 300. In an exemplary embodiment, arm 16 may pivot about axis B to inspection station 320 so the finish of cables 70 made be inspected by means discussed further herein.
In block 202, after mounting cables 70 to fixture 50, a user or an automation may lower mounted cables 70 toward polishing platform 12, which is loaded with a polishing film 80, until cables 70 contact (e.g., are pressing against) polishing film 80 at a desired pressure. For example, arm 16 may be lowered using dials 38 and one or more linear slides so that attached mounting fixture 50 is, consequently, lowered toward platform 12, which has polishing film 80 secured thereto (e.g., secured to surface 84 of platform 12). Simultaneously, the process may include monitoring the downward force applied against platform 12 using force gauge 20.
In block 204, a user may begin the polishing process, allowing the process to proceed for a predetermined duration of time. As mentioned herein, the rotational speed of platform 12 may gradually increase once cables 70 are in contact with polishing film 80 to remove any imperfections on the surfaces of cables 70. In one or more embodiments, arm 16 may also increase pressure between cables 70 and platform 12 during the polishing process. Thus, the process may include adjusting the downward force to remain with a prescribed tolerance. In one or more embodiments, arm 16 may rotate fixture 50 about axis A. In one or more embodiments, the predetermined duration of time may be chosen by a user or may be determined, for example, by the computer processing unit.
In block 206, a user or computer processing unit (e.g., electronic device 302) may stop polishing so that the user or computer processing unit may analyze cables 70. For example, arm 16 may move fixture 50 over to inspection station 320 so that a user or electronic device 302 may analyze and determine the current status of the polish on each cable 70. For manual inspection, a user may do an optical inspection of cables 70 by referencing an exemplary image of a polished cable that is, for example, provided by electronic device 302, as shown in block 208. The user may then determine from the exemplary image whether or not cables 70 are within the desired tolerance or percentage of yield, as shown in block 212. For automated inspection, cables 70 may be scanned, for example, by camera 304, which is communicatively coupled to the electronic device 302 so that electronic device 302 may determine the tolerance or percentage of yield of each cable 70, as shown in block 210. For example, camera 304 may relay inspection footage to electronic device 302, which is, optionally, loaded with software that compares the polish of cables 70 to an intermediate or final standard. In one or more embodiments, camera 304 provides a live feed to electronic device 302, which may be shown on a display of electronic device 302. After inspecting cables 70, electronic device 302 may determine if the desired percentage of yield is achieved, as shown in block 212.
In one or more embodiments, inspection is performed after washing cables 70 in ultrasonic bath 306 by instructing arm 16 to move fixture 50 with cables 70 away from ultrasonic bath 306 at washing station 310 and continue the rotational path to inspection station 320, which itself may have one or more inspecting cameras, such as camera 304. Since polishing assembly 10 may use a stepper motor and at least one bearing (e.g., a roller bearing), mounting fixture 50 may be moved in any direction to any position necessary for proper inspection. For example, fixture 50 may rotate, pivot, or slide in any direction while camera 304 at inspection station 320 is scanning each cable 70. After scanning cables 70, electronic device 302 may provide data regarding the percentage of yield and, if applicable, the additional time required to achieve the desired percentage of yield.
In one or more embodiments, inspection can be performed by visual inspection under magnification, surface scattering approaches, or performed by a camera (e.g., camera 304) coupled to a computer or viewing monitor for surface analysis (e.g., electronic device 302), which eliminates any subjective aspect of inspection. As shown in block 212, inspection can result in a positive or negative response. A positive response demonstrates that the polished material is of suitable quality and, thus, passes inspection. A negative response demonstrates that the polished material is not of suitable quality and must be reworked.
If the user or computer processing unit determines the percentage of yield to be acceptable (e.g., within 90%), then cables may be removed from mounting fixture 50, as shown in block 214. If the user or computer processing unit determines, that the desired percentage of yield has not been achieved, then the process may return to block 202, continuing the polishing process until cables 70 are within the desired percentage of yield and are, thus, found to have an acceptable polish.
In an exemplary embodiment, upon a positive response, optionally, mechanical arm 16 can move fixture 50 away from the inspection station 320 to a collection station (not shown) for collecting cables 70. Collection may include releasing fixture 50 from mechanical arm 16 and/or opening clamps 54 to remove cables 70. As such, the positive response can also include releasing clamps 54, whether by manually flipping tabs 56 upward (e.g., away from pad 46) or through automation, thereby allowing removal of polished cables 70 and, optionally, insertion of a next batch of cables for polishing.
On the other hand, upon a negative response, mechanical arm 16 can return fixture 50 to its polishing position at polishing station 300 for additional polishing. Thus, the negative response can also instruct polishing platform 12 to speed up, thereby saving processing time.
The skilled artisan will appreciate that the steps of polishing, washing, and inspection may be performed as a single cycle, as a series of cycles, or the steps be reordered over multiple cycles as desired. For instance, the method may perform two or more polishing and washing steps prior to the inspection step. In some instances, polishing with different polishing films 80, such as progressing from 3 μm to 9 μm diamond films, may be performed prior to inspection.
After removal, cables 70 are packaged using approaches known in the art for use in a variety of industries such as telecommunications, medical diagnostics, medical therapeutics (e.g. surgery and dentistry), automotive, lighting, mechanical inspection and analytical instrumentation, military and aerospace industries.
The foregoing disclosure of exemplary embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. As example, the methods may also include a pretreatment step, where the cables 70 are pretreated with a solution prior to polishing. In some embodiments, the pretreatment occurs by dipping the cables 70 in the ultrasonic bath.
Further, in describing representative embodiments, the specification may have presented the method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims.
While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.
This application claims benefit of priority to U.S. patent application No. 62/985,172, filed Mar. 4, 2020, the content of which is herein incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/020738 | 3/3/2021 | WO |
Number | Date | Country | |
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62985172 | Mar 2020 | US |