Patent Application
20150089880
The present disclosure relates generally to downhole tools used in subterranean drilling, and more particularly, to the manufacture of drill bits that have polycrystalline diamond compact (PDC) cutters.
Drill bits are commonly used for drilling bore holes or wells in earth formations. A PDC drill bit may include a tungsten carbide or steel body and a plurality of cutters (PDC cutters) that have a polycrystalline diamond (PCD) portion. The PCD portion of a PDC cutter is typically exposed to the earth formation. PDC includes a polycrystalline diamond table that enables PDC cutters to have high level of hardness and resistance to wear.
Typically, PDC cutters and the bit body of a drill bit are manufactured separately, and the PDC cutters are subsequently attached to the bit body. After a PDC cutter is placed in a corresponding pocket in the bit body, a brazing operation is performed to attach the PDC cutter to the bit body (i.e., to the wall of the pocket). A braze material (e.g., an alloy, such as Castolin 1703, BAG 22 and BAG 24) is commonly used in the brazing operation to secure each PDC cutter to the bit body within its corresponding pocket. For example, after a braze alloy is placed between a PDC cutter and the wall of a pocket, heat may be applied (typically using a blow torch) to melt the braze alloy, which also heats up the PDC cutter that is in the pocket. Upon removal of the heat, the melted braze alloy solidifies to bond the PDC cutter to the wall of the pocket.
Brazing operations are generally performed manually by one or more individuals. For example, one individual may apply heat to a braze alloy to melt the braze alloy within a cutter pocket while another individual spins the PDC cutter within the pocket to evenly distribute the melted braze alloy. Unfortunately, a manual brazing operation can be a source of many problems that detrimentally affect the quality of a PDC drill bit. For example, a significant factor that affects the quality of PDC drill bit is excessive exposure of the PDC cutters to heat. Both excessive duration of exposure to heat and excessive temperature caused by the applied heat are factors that can diminish the quality of the PDC cutters due to thermal damage to the PCD portion of the PDC cutters.
For example, because a brazing operator often relies on the operator's own judgment to determine whether a brazing alloy is adequately melted to properly bond a PDC cutter within a cutter pocket of a bit body, the brazing operator may mistakenly expose the PDC cutter to heat for an excessive duration of time and/or to excessive temperature that result in the PDC cutter being damaged. Further, the bond between the PDC cutter and the pocket may not be properly formed due to an operator's misjudgment on whether braze alloy is adequately melted within the cutter pocket. Because different brazing operators may make different decisions on the adequate duration and amount of heat (for example, from a blow torch) that is needed to melt the brazing alloy, PDC drill bits manufactured by the same entity may have inconsistent levels of quality.
The foregoing and other features and aspects of the invention will be best understood with reference to the following description of certain exemplary embodiments of the invention, when read in conjunction with the accompanying drawings, wherein:
The drawings illustrate only exemplary embodiments of the invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments.
The present disclosure relates generally to downhole tools used in subterranean drilling. In particular, this disclosure relates to the manufacture of drill bits that have cutters (e.g., PDC cutters) that are adversely affected by excessive heat during drill bit manufacturing processes. Although the description of the exemplary embodiments is provided with respect to PDC drill bits and PDC cutters, embodiments that include drill bits other than PDC drill bits are contemplated within the scope of this description.
The present invention may be better understood by reading the following description of non-limiting, exemplary embodiments with reference to the attached drawings, wherein like parts of each of the figures are identified by like reference characters. According to an exemplary embodiment, a method of manufacturing PDC drill bits includes inspecting a plurality of cutters to determine a size of each cutter of the plurality of cutters. The method further includes inspecting a plurality of pockets of a bit body to determine a size of each pocket of the plurality of pockets. A cutter of the plurality of cutters is assigned to a pocket of the plurality of pockets based on the inspection of the plurality of cutters and the inspection of the plurality of cutter pockets. A robot positions the cutter inside the pocket and applies heat to a brazing material to produce a molten brazing material within the pocket.
According to an exemplary embodiment, a system for manufacturing PDC drill bits includes a camera for inspecting a plurality of cutters and for inspecting a plurality of pockets of a bit body. The system further includes a robot configured to position a PDC cutter of a plurality of PDC cutters inside a pocket of a plurality of pockets of the bit body and to apply heat to a brazing material to produce a molten brazing material within the pocket of the plurality of pockets. The system further includes a heating system for heating the bit body including the plurality of pockets to a preheat temperature.
According to an exemplary embodiment, an automated device for use in a manufacture of PDC drill bits includes a controller, a first arm for positioning a cutter of a plurality of cutters inside a pocket of a plurality of pockets of a bit body, and a second arm for applying heat to a brazing material to produce a molten brazing material within the pocket of the plurality of pockets, wherein the controller is configured to control the first arm and the second arm.
According to an exemplary embodiment, a computer system includes a module for controlling inspections of a plurality of cutters and inspections of a plurality of pockets of a bit body. The computer system further includes a module for controlling assignment of a cutter of the plurality of cutters to a pocket of the plurality of pockets based on the inspection of the plurality of cutters and the inspection of the plurality of cutter pockets. The computer system also includes a module for controlling operations of a robot in positioning the cutter of the plurality of cutters inside the pocket of the plurality of pockets, and a module for controlling application of heat by the robot to a brazing material to produce a molten brazing material within the pocket.
The robot arms 102, 104 of the robot 106 may perform a number of functions. For example, an end piece of each arm 102, 104 may be changed to a different piece, as needed, to perform different functions. One of the arms 102, 104 may operate one or more cameras 114 to inspect PDC cutters 118 to determine a shape and size of each cutter. The robot 106 may also use the arms 102, 104 to inspect the pockets 120 of the bit body 110 to determine a shape and size of each pocket. One or more subsequent inspection of the pockets 120 may be performed following the initial inspection to help in the positioning of each cutter in a corresponding pocket. Following the initial inspection of the cutters 118, the controller 130 or another controller may perform image analysis on image information from the one or more cameras 114 to determine the shape and size of each cutter and each pocket. Each cutter may be assigned to a corresponding pocket in the bit body 110 based on the inspection of the cutters 118 and the pockets 120. For example, each cutter may be assigned to a pocket based on the size of the cutter and the size of the pocket. Alternatively, each cutter may also be assigned to a pocket based on both the shape and size of the cutter and of the pocket.
After the pockets are inspected and each cutter is assigned to a corresponding pocket, a flux material, such as Degussa h80, may be applied to the bit body 110. The flux material is applied to the bit body 110 to minimize oxidation of the bit body 110 during subsequent brazing operations. For example, a powder form of the flux material may be spread on the bit body 110, and heat may be applied by the heating system 108 to the bit body 110 as well as to the flux material spread on the bit body 110. The heating system 108 may apply the heat to increase the temperature of bit body 110 and the flux material to above the activation temperature of the flux material. Alternatively, the flux material may be applied to the bit body 110 after the bit body 100 is heated by the heating system 108 to a preheat temperature that equals or exceeds the activation temperature of the flux material. The controller 130 may control operation of the heating system 108, for example, by turning on and off heat from the heating system 108 to maintain the bit body 110 within a particular range of temperature values. In an example embodiment, the activation temperature range of the flux material is between approximately 540° C. and 610° C.
Similarly, after the cutters 118 are inspected and each cutter is assigned to a corresponding pocket in the bit body 110, a flux material may be applied to the cutters 118 to minimize oxidation of the cutters 118 when the cutters 118 are later exposed to higher temperature during the brazing operation. For example, the cutters 118 may be immersed in a flux bath 122 of the flux application system 112 that includes a heater to heat the cutters 118 and/or the flux material to near a preheat temperature equal or above the activation temperature of the flux material. In alternative exemplary embodiments, the cutters 118 may be heated to a temperature, for example, above the activation temperature of the flux material and dipped in the flux material to apply the flux material to the cutters 118.
For example, one or both of the robot arms 102,104 may perform the function of dipping the heated cutters into the flux material. In an example embodiment, the controller 130 may control heating of the PDC cutters 118 in the application of the flux material. To minimize damage to the PDC cutters 118 due to excessive heat exposure, the temperature of the PDC cutters 118 may be maintained close to the activation temperature of the flux material during and subsequent to the application of the flux material. After the PDC cutters 118 are covered with the melted flux material, the PDC cutters 118 are placed in the pockets 120, where the heating system 108 continues to apply heat as needed to maintain the bit body 110 and the cutters 118 that are positioned in the pockets 120 of the bit body 110 near a preheat temperature equal or above the activation temperature of the flux material.
After the flux material is applied to the bit body 110 and to the PDC cutters 118, the robot 106 may start positioning each cutter of the cutters 118 inside a corresponding pocket of the pockets 120. For example, the robot 106 may position each cutter inside a corresponding pocket using one or both arms 102, 104 and based on the assignment of each cutter to the corresponding pocket. One or both of the arms 102, 104 may place each cutter such that a center of the cutter is positioned substantially directly over a center of the corresponding pocket. The robot 106 determines the center of each cutter and the center of each pocket based on the inspection of the cutters 118 and of the pockets 120 performed using the one or more cameras 114.
After a particular cutter is positioned in a corresponding pocket, the robot 106 may place a brazing material within the pocket between the cutter and the pocket wall(s). Again, the robot 106 may perform this function using one or both arms 102, 104. In an exemplary embodiment, the brazing material may have a melting temperature ranging between 705° C. and 750° C. For example, an alloy, such as Castolin 1703, BAG 22 and BAG 24, may be used as a brazing material. The brazing material may be placed within the pocket while the heating system 108 continues to apply heat to maintain the bit body 110 and the cutter near the preheat temperature.
To bond the cutter that is placed in the corresponding pocket to the bit body 110, the robot 106 may apply heat for a duration of time to the brazing material that is placed within the pocket. For example, the arm 104 (or another robot arm) may be used to apply heat to the brazing material using a heat source 116. The controller 130, a controller within the robot 106, another controller, or a combination thereof may control operation of the arm 104 and the amount and duration of heat that is applied to the brazing material. The heat source 116 may apply heat to the brazing material, for example, using a flame or an induction coil. For example, the heat source 116 may heat up an induction coil that is positioned within the pocket that in turn heats up the brazing material. Use of an induction coil instead of a flame may limit the effect of the heat on neighboring pockets and on corresponding PDC cutters positioned in the pockets.
The robot 106 controls the amount of heat that is applied to achieve a desired brazing temperature, which is a temperature at which the brazing material is adequately melted to form a bond between the cutter and the bit body 110 when the brazing material cools down. The robot 106 also controls the duration of heat application to the brazing material. In some exemplary embodiments, the robot 106 may apply an amount of heat to the brazing material for a duration of time that is determined prior to the application of the heat starts. Alternatively, the robot 106 may apply an amount of heat for a duration of time that is based on temperature information (for example, from a temperature sensor) that indicates the temperature of the brazing material and/or the area around the brazing material. The robot 106 may also adjust the amount of heat as needed to achieve the desired brazing temperature.
In some alternative exemplary embodiments of the brazing operation, the robot 106 may first apply heat to the pocket prior to the placement of the brazing material to increase the temperature of the bit body (e.g., the wall of the pocket) to the melting temperature of the brazing material. For example, the robot 106 may apply heat to the wall of a particular pocket, and once the wall of the particular pocket reaches or exceeds the melting temperature of the brazing material, the robot 106 may bring the brazing material in contact with the wall of the pocket in order to melt the brazing material within the pocket.
During the brazing operation, while one arm 104 is applying heat to the brazing material and/or to the bit body, the other arm 102 may spin the cutter within the pocket to evenly distribute the melted brazing material within the pocket and to push the melted flux material out of the pocket. After the brazing material is melted and the cutter is spun within the pocket for a duration of time to adequately remove the molten flux material from the pocket, the robot 106 may perform an adjustment in the position of the PDC cutter within the pocket. After performing a final positioning of the PDC cutter within the pocket, the robot 106 removes the heat to allow the melted brazing material to cool down and solidify forming a bond between the cutter and the bit body 110.
The robot 106 may perform placement of each cutter of the cutters 118 in a corresponding pocket of the pockets 120 and perform the brazing operation as described above. Because the robot 106 can consistently control the amount of heat used in the brazing operation and the duration of heat application, the cutters 118 get bonded to the bit body 110 in a consistent manner, which also result in consistent level of quality between different PDC drill bits.
Although two robot arms are described above and shown in
As illustrated, the one or more cameras 114 are attached to the robot arm 102. For example, the robot arm 102 may move the one or more cameras 114 as needed to collect information about the pockets 120. For example, the one or more cameras 114 may collect dimension information of the pockets 120. The dimension information may be used, for example, by the controller 130 or another dedicated controller, to enable determination of shape and size of a particular pocket. The dimension information may also be used to determine a center of a particular pocket. In some exemplary embodiments, the dimension information may enable generation of a 3-dimensional (3D) view of the pockets 120.
In some exemplary embodiments, a knob 204 or 5 axes CN machines (not shown) may be used for adjusting the position of the bit body 110. For example, once the one or more cameras 114 collect adequate information on the pockets that are exposed through the opening in the heating system 108, the knob 204 may be used to rotate the bit body 110, such that pockets that are, for example, in the back of the heating system 108 become accessible to the one or more cameras 114. Although a 5 axes CN machine has been mentioned above to use within the exemplary embodiments described herein, the CN machine has a different number of axes, such as 3 axes or 4 axes, in other exemplary embodiments.
In the exemplary embodiment of
For example, the controller 130 may use the information collected through inspection of the pockets 120 and the cutters to assign each cutter to a matching pocket. For example, the pockets on each blade may be identified by the position of the particular pocket on the particular label. To illustrate, the pockets on a particular blade may be designated 1 to N. Accordingly, each cutter may be assigned a label BxCy, where x identifies the particular blade and where y identifies the particular pocket on the blade x. For example, a cutter labelled B1C5 is assigned to pocket 5 on blade 1. Computer-aided design (CAD) systems may be used in designating blades and pockets and enable assignment of cutters to pockets.
In some alternative exemplary embodiments, the robot arm 102 may pick up the cutter 118 from the cutter tray 304 prior to the application of a flux material and immerse the cutter in a flux material (for example, by dipping the cutter in a flux bath 122 of
In an alternative exemplary embodiment, the operation illustrated in
In an exemplary embodiment, the robot arm 102 may spin the cutter 118 within the pocket 102 as a brazing material 406 is being applied within the pocket 120. For example, while the robot arm 104 applies heat to the brazing material 406 subsequent to positioning of the brazing material 406 within the pocket 120, the arm 102 may spin the cutter 118 within the pocket 120 to evenly distribute the melted brazing material within the pocket 120 and to push the melted flux material out of the pocket 120. After the brazing material 120 is melted and the cutter 118 is spun within the pocket for a duration of time to adequately remove any molten flux material from the pocket 120, the robot arm 102 may perform an adjustment in the position of the cutter 118 within the pocket 120. Subsequent to performing the final adjustment of the position of the cutter 118 within the pocket 120, the melted brazing material is allowed to cool down and solidify forming a bond between the cutter 118 and the bit body 110 within the pocket 120.
For example, as illustrated in
To illustrate, a powder form of a flux material may be spread on the bit body 110 of
At step 510 of the method 500, the robot positions the cutter of the plurality of cutters inside the pocket of the plurality of pockets. For example, as illustrated in
At step 512 of the method 500, the robot applies heat to a brazing material to produce a molten brazing material within the pocket. For example, the robot arm 104 shown in
In some exemplary embodiments, the method 500 may also include spinning a cutter within a pocket of the bit body while a brazing material is being applied within the pocket. Spinning the cutter while applying the brazing material helps to evenly distribute the melted brazing material within the pocket and to push melted flux material out of the pocket. For example, a cutter may be spun within a pocket while applying heat to melt a brazing material that is previously positioned within the pocket. To illustrate, the robot arm 102 shown in
Although
In some exemplary embodiments, the computer system 600 includes an inspection control module 604 for controlling inspections of a plurality of cutters (e.g., the PDC cutters 118 of
The computer system 600 may also include a cutter placement module 610 for controlling operations of a robot (e.g., the robot 106 of
The brazing material application module 614 may control placement of a brazing material within the pocket, for example, prior to applying the heat to melt the brazing material. For example, the brazing material application module 614 may control placement of the brazing material 406 described with respect to
The brazing heat application module 616 may control application of heat by the robot to a brazing material to produce a molten brazing material within the pocket. For example, the brazing heat application module 616 may control the application of heat to melt the brazing material 406 described with respect to
The different modules 604-616 may interact with the components of the system 100 of
Although a particular topography of the modules is illustrated in
Although each exemplary embodiment has been described in detailed, it is to be construed that any features and modifications that is applicable to one embodiment is also applicable to the other embodiments.
Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons of ordinary skill in the art upon reference to the description of the exemplary embodiments. It should be appreciated by those of ordinary skill in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or methods for carrying out the same purposes of the invention. It should also be realized by those of ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. It is therefore, contemplated that the claims will cover any such modifications or embodiments that fall within the scope of the invention.
