Patent Publication Number: US-9853368-B2

Title: Electrical crimp terminal

Description:
BACKGROUND OF THE INVENTION 
     The subject matter described and/or illustrated herein relates generally to electrical crimp terminals configured to be crimped to electrical devices, such as cables or wires. 
     Electrical crimp terminals are often used to terminate the ends of wires or other electrical devices. Some electrical terminals include a crimp barrel and an electrical contact. The crimp barrel is crimped around the end of the wire to establish an electrical connection between electrical conductors in the wire and the terminal as well as to mechanically hold the electrical terminal on the wire. When crimped over the wire, the crimp barrel establishes an electrical and mechanical connection between the conductors of the wire and the electrical contact of the terminal, such that the terminal carries current from the wire to the mating component connected to the electrical contact. 
     Conductors of wires are often fabricated from metal materials, such as copper and aluminum, which may form poorly conductive oxide layers on the exterior surface of the wire conductors when exposed to air. Furthermore, build-up of surface contaminants from processing steps may further inhibit surface conductivity. Such exterior conductor surface oxide layers must be penetrated in order to form reliable metal-to-metal connections between the metal material of the wire and the metal material of the electrical crimp terminal. For example, some crimp barrels include one or more serrations that, during a crimping operation, are configured to scrape or wipe against the conductors of the wire to displace the oxide layer and expose fresh metal of the conductors for establishing a metal-to-metal connection. 
     But, it may be difficult to displace enough of the oxide layer during the crimping operation to achieve a sufficient electrical and mechanical bond, and thereby establish a reliable electrical connection, especially for electrical terminals formed of metal materials that are similar in strength to the materials of the wire conductors. For example, some electrical terminals are formed of lower-strength metals than traditional terminals in order to reduce cost and improve electrical conductivity of the terminals relative to higher-strength metals. But, during a crimping operation, when the terminal has a similar strength or elasticity as the wire conductors, both the terminal and the wire conductors may extrude or flow with similar characteristics such that there may be little differential or relative flow between the terminal and the wire conductors. The reduced differential flow inhibits the ability for the existing serrations to wipe and scrape against the conductors to displace the oxide layer, resulting in a poor electrical connection between the terminal and the wire. 
     A need remains for an electrical crimp terminal that is able to displace the oxide layer on electrical conductors in the crimp barrel during a crimping operation to provide a reliable electrical connection between the terminal and the electrical conductors, even when there is limited differential flow between the metal of the terminal and the metal of the conductors during the crimping operation. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, an electrical terminal is provided that includes a crimp barrel having an interior side and an exterior side. The interior side of the crimp barrel defines a channel that extends along a longitudinal axis. The crimp barrel is configured to mechanically hold and electrically connect to one or more electrical conductors of an electrical device received in the channel. The crimp barrel includes multiple primary serrations spaced apart along the longitudinal axis. The primary serrations are groove-shaped recesses formed along the interior side. Adjacent primary serrations are separated from one another by a band. The crimp barrel further includes at least one micro-serration on the band. Each micro-serration is a groove-shaped recess formed along the interior side that has a smaller size relative to the primary serrations. 
     In another embodiment, an electrical terminal is provided that includes a crimp barrel extending along a longitudinal axis between a contact end and a device end. The crimp barrel has an interior side that defines a channel extending along the longitudinal axis. The crimp barrel is configured to mechanically hold and electrically connect to one or more electrical conductors of an electrical device received in the channel. The crimp barrel includes multiple primary serrations and multiple micro-serrations in a serration array. The primary serrations and the micro-serrations are groove-shaped recesses formed along the interior side. The micro-serrations have a smaller size relative to the primary serrations. The micro-serrations are arranged in groups of at least one micro-serration. The groups of the micro-serrations and the primary serrations are arranged in an alternating sequence along the longitudinal axis such that one of the primary serrations is disposed between adjacent groups of micro-serrations and one of the groups of micro-serrations is disposed between adjacent primary serrations. 
     In another embodiment, an electrical terminal is provided that includes a crimp barrel having an interior side and an outer side. The interior side of the crimp barrel defines a channel that extends along a longitudinal axis. The crimp barrel is configured to mechanically hold and electrically connect to one or more electrical conductors of an electrical device received in the channel. The crimp barrel includes multiple primary serrations spaced apart along the longitudinal axis. Adjacent primary serrations are separated from one another by a band. The crimp barrel further includes at least one micro-serration on the band. The primary serrations and the at least one micro-serration are groove-shaped recesses formed along the interior side. The micro-serrations have a smaller size relative to the primary serrations. The primary serrations and the at least one micro-serration define barrel teeth. Each barrel tooth has a top surface that faces the channel and two tapered sides extending from two corresponding edges of the top surface. The edges of the barrel teeth are configured to engage and scrape against the one or more electrical conductors during a crimping operation to form metal-to-metal contacts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical crimp terminal and an electrical device according to an embodiment. 
         FIG. 2  is a bottom perspective view of a punching die and a portion of the electrical crimp terminal according to an embodiment. 
         FIG. 3  is a cross-sectional view showing the punching die in contact with a crimp barrel of the electrical crimp terminal. 
         FIG. 4  is a close-up portion of the punching die and the crimp barrel shown in  FIG. 3 . 
         FIG. 5  is a cross-sectional view of a serration array on the crimp barrel of the electrical crimp terminal taken along line  5 - 5  shown in  FIG. 1 . 
         FIG. 6  is a close-up portion of the serration array on the crimp barrel shown in  FIG. 5 . 
         FIG. 7  is a cross-sectional view of a portion of a terminal assembly including one or more conductors of the electrical device in the crimp barrel of the electrical crimp terminal. 
         FIG. 8  shows the terminal assembly in a post-crimped state according to an embodiment, such that the crimp barrel is compressed into mechanical engagement and electrical contact with the one or more conductors of the electrical device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One or more embodiments described herein disclose an electrical terminal configured to be crimped to an electrical device, such as a wire or a cable, to form a terminal assembly (or contact lead). The electrical terminal may provide an improved electrical connection with the electrical device to which the terminal is crimped relative to known terminals. For example, the electrical terminal includes a serration array that includes serrations of multiple different sizes along an interior side of the terminal that engages the conductors of the electrical device. The serration array may provide enhanced scraping to remove or displace the poorly-conductive oxide layer on the conductors relative to the serrations on known terminals. For example, the serration array of the terminal disclosed herein may take advantage a limited differential flow or extrusion of the conductors relative to the terminal during the crimping process, which occurs when metal material of the conductors flows towards and at least partially fills the recesses formed by larger serrations of the serration array. As the metal material of the conductors flows towards the larger serrations, edges of the smaller serrations (which are proximate to the larger serrations) scrape against the metal material to remove and/or displace the oxide layer, creating a reliable metal-to-metal electrical connection. Since the serration array takes advantage of a limited differential flow between the conductors and the terminal, the terminal may be formed of a metal material that has a similar strength or elasticity as the metal material of the conductors. The metal material of the terminal may be preferable over metal materials used for known terminals because, for example, the metal material of the terminal disclosed herein may have a higher conductivity and a lower cost than the materials of known terminals. 
       FIG. 1  is a perspective view of an electrical crimp terminal  100  and an electrical device  102  according to an embodiment. The electrical device  102  may be a wire, a cable, or another structure with current-carrying conductors  106 . The electrical device  102  is configured to be crimped to the terminal  100 . The terminal  100  includes a crimp barrel  104  that receives a portion of the electrical device  102  therein. In  FIG. 1 , the electrical device  102  is poised for loading into the crimp barrel  104  prior to a crimping operation. During the crimping operation, the crimp barrel  104  is pressed into engagement with one or more electrical conductors  106  of the electrical device  102  to electrically connect the terminal  100  to the electrical device  102 . The one or more electrical conductors  106  may be one or more metal wires, strands, or the like. The crimping operation also mechanically secures the terminal  100  to the electrical device  102 , forming a terminal assembly (or electrical lead). 
     The terminal  100  is oriented with respect to a longitudinal axis  191 , a lateral axis  192 , and a vertical or elevation axis  193 . The axes  191 - 193  are mutually perpendicular. Although the elevation axis  193  appears to extend generally parallel to gravity, it is understood that the axes  191 - 193  are not required to have any particular orientation with respect to gravity. The terminal  100  extends a length along the longitudinal axis  191  between a front end  108  and a rear end  110 . The terminal  100  has a crimp segment  114 , a contact segment  116 , and a transition segment  118  that are spaced apart along the longitudinal axis  191 . The crimp segment  114  defines the rear end  110 , the contact segment  116  defines the front end  108 , and the transition segment  118  is disposed between the crimp and contact segments  114 ,  116 . As used herein, relative or spatial terms such as “front,” “rear,” “left,” “right,” “top,” and “bottom” are only used to identify and distinguish the referenced elements and do not necessarily require particular positions or orientations relative to the surrounding environment of the terminal  100 . 
     The contact segment  116  includes an electrical contact  120 . In the illustrated embodiment, the electrical contact  120  is a pin or beam that is configured to be received in a socket or receptacle of a mating contact (not shown). But, the electrical contact  120  may have other shapes in other embodiments, such as, but not limited to a cage-shaped receptacle, a spring contact, a tab, a pole shoe, or the like. The transition segment  118  may provide structural support for the terminal  100  and/or a means for retaining the terminal  100  in a housing (not shown). For example, the transition segment  118  may include a protrusion  119  that is configured to engage a latch or shoulder of the housing. The crimp segment  114  includes the crimp barrel  104 . In the illustrated embodiment, the crimp segment  114  also includes an insulation crimp barrel  122  that is disposed rearward of the crimp barrel  104  (which is a conductor crimp barrel). The insulation crimp barrel  122  is configured to be crimped into engagement with an insulation layer  124  of the electrical device  102 . The insulation layer  124  surrounds the one or more electrical conductors  106 . An exposed portion  126  of the one or more electrical conductors  106  protrudes from the insulation layer  124 . The exposed portion  126  is received in the crimp barrel  104 , unlike the insulation layer  124 . In an alternative embodiment, the terminal  100  does not include the contact  120  and/or the transition segment  118 . For example, the terminal  100  may only include the crimp barrel  104  and may be configured to join two electrical devices  102  end-to-end. 
     The crimp barrel  104  extends along the longitudinal axis  191  between a contact end  128  and a device end  130 . The device end  130  is rearward of the contact end  128 . The crimp barrel  104  defines a channel  132  that receives the exposed portion  126  of the one or more conductors  106  therein in preparation for a crimping operation. In the pre-crimped state of the terminal  100  shown in  FIG. 1 , the crimp barrel  104  has a U- or V-shaped cross-section taken along the lateral axis  192 . The crimp barrel  104  includes a base  134  and two wings or tabs  136  that extend from laterally opposite lateral sides of the base  134 . The channel  132  is defined by an interior side  138  of the barrel  104 . The channel  132  is open along a top  140  of the terminal  100  between distal ends  142  of the wings  136 . During the crimping operation, the wings  136  are bent towards one another into the channel  132  to engage the one or more conductors  106  of the electrical device  102 . The terminal  100  is an “F” type terminal in an embodiment, but in other embodiments the terminal  100  may be an “0” type terminal that has a closed cylindrical barrel instead of an open, U-shaped barrel. 
     The crimp barrel  104  includes a serration array  144  along the interior side  138 . The serration array  144 , as shown and described in more detail herein, includes at least one primary serration  146  and at least one micro-serration  148  spaced apart along the longitudinal axis  191 . Multiple primary serrations  146  and multiple micro-serrations  148  are shown in  FIG. 1 . The primary serrations  146  and micro-serrations  148  are recesses along the interior side  138  in the shape of grooves. The micro-serrations  148  have a smaller size than the primary serrations  146 . As used herein, the term “micro-serrations” merely identifies a type of serration that is smaller in at least one size dimension than the primary serrations  146 , and is not used to signify a specific size range or scale. 
     In the illustrated embodiment, the primary serrations  146  and the micro-serrations  148  are elongated laterally along the interior side  138  of the crimp barrel  104 . For example, the serrations  146 ,  148  extend along the base  134  and along the wings  136  towards the distal ends  142  of the wings  136 . Each serration  146 ,  148  may extend continuously from one wing  136  to the other wing  136 , or may be divided into multiple segments along the lateral length of the respective serration  146 ,  148 . In an embodiment, the primary serrations  146  extend parallel to one another. The micro-serrations  148  extend parallel to one another and parallel to the primary serrations  146 . The primary serrations  146  and the micro-serrations  148  extend transverse to the longitudinal axis  191 , such as perpendicular to the longitudinal axis  191 . 
     During a crimping operation, the exposed portion  126  of the one or more conductors  106  is received in the channel  132  of the crimp barrel  104 , and the electrical device  102  extends from the device end  130  of the crimp barrel  104 . The one or more conductors  106  are held generally coaxial with the longitudinal axis  191 . The serrations  146 ,  148  of the serration array  144  extend around a perimeter of the one or more conductors  106 . The terminal  100  is located on an anvil (not shown) of a crimping apparatus. A crimp tooling member (not shown) of the crimping apparatus descends from above the terminal  100 . The crimp tooling member engages an exterior side  150  of the crimp barrel  104  and bends the wings  136  to engage and surround the one or more conductors  106  in the channel  132 . The serration array  144 , as described herein, is configured to wipe and/or scrape an exterior surface of the one or more conductors  106  as the crimp barrel  104  is compressed around the conductors  106  to remove and/or displace an oxide layer on the conductors  106 , creating metal-to-metal bonds via cold welding. 
       FIG. 2  is a bottom perspective view of a punching die  200  and a portion of the terminal  100  according to an embodiment. In  FIG. 2 , a bottom side  202  of the punching die  200  engages the interior side  138  of the crimp barrel  104  to form the serration array  144  (shown in  FIG. 1 ).  FIG. 3  is a cross-sectional view showing the punching die  200  in contact with the crimp barrel  104 .  FIG. 4  is a close-up portion of the punching die  200  and the crimp barrel  104  shown in  FIG. 3 . 
     The terminal  100  is shown in  FIGS. 2-4  having a flat, planar shape. For example, the terminal  100  may be produced by stamping and forming a metal panel or sheet. As shown in  FIG. 2 , the terminal  100  has already been stamped prior to contacting the punching die  200 , but the terminal  100  has not yet been formed. The crimp barrel  104  is formed into the U-shape shown in  FIG. 1  subsequent to forming the serration array  144 . Although not shown in  FIG. 2 , the terminal  100  may be placed on a die plate  204  for the punching operation shown in  FIGS. 2-4 . As show in  FIG. 3 , the exterior side  150  of the crimp barrel  104  engages the die plate  204 , and the punching die  200  is moved in a punching direction  206  vertically towards the terminal  100  from above the terminal  100 . 
     The punching die  200  includes multiple elongated ridges  208  that protrude from the bottom side  202  thereof. The ridges  208  engage the interior side  138  of the crimp barrel  104  to form the serration array  144  (shown in  FIG. 1 ). In an embodiment, the ridges  208  include primary ridges  208 A and micro-ridges  208 B. The primary ridges  208 A have a larger size than the micro-ridges  208 B. The primary ridges  208 A form the primary serrations  146  (shown in  FIG. 1 ), and the micro-ridges  208 B form the micro-serrations  148  ( FIG. 1 ). As shown in  FIG. 2 , the primary ridges  208 A extend parallel to the micro-ridges  208 B. The ridges  208  may be formed by machining the bottom side  202  of the punching die  200  to define the protruding ridges  208 . As shown in  FIG. 2 , the punching die  200  includes multiple micro-ridges  208 B on either side of each primary ridge  208 A such that multiple micro-ridges  208 B are disposed between each pair of adjacent primary ridges  208 A. The ridges  208 A,  208 B may be configured in other arrangements in other embodiments. 
       FIGS. 3 and 4  show the punching die  200  at a bottom dead position relative to the die plate  204  and the terminal  100  thereon. The bottom dead position represents the end of a punch stroke. Therefore, the punching die  200  does not move closer to the die plate  204  than the position shown in  FIGS. 3 and 4 . At the bottom dead position, the ridges  208  engage the terminal  100  and protrude into the interior side  138 . The portions of the bottom side  202  of the punching die  200  surrounding the ridges  208  and between the ridges  208  are spaced apart from and do not engage the terminal  100 . The terminal  100  is compressed between the ridges  208  of the punching die  200  and the die plate  204 . As the ridges  208  compress the terminal  100  along the crimp barrel  104 , the ridges  208  displace some of the metal material of the terminal  100 . For example, the ridges  208  force the metal material to flow to areas of reduced pressure, such as into the cavities  210  between adjacent ridges  208 . As shown in  FIG. 4 , the interior side  138  of the terminal  100  between adjacent ridges  208  defines concave surfaces  182 . The concave surfaces  182  are bowed between outer edges  184  such that a middle portion  186  of each concave surface  182  is more proximate to the exterior side  150  (shown in  FIG. 3 ) of the crimp barrel  104  than a proximity of the outer edges  184  to the exterior side  150 . Thus, the outer edges  184  are raised relative to the middle portion  186 . The concave surfaces  182  are formed from the displacement of metal material of the terminal  100  as the ridges  208  penetrate the crimp barrel  104 . 
       FIG. 5  is a cross-sectional view of the serration array  144  on the crimp barrel  104  of the terminal  100  (shown in  FIG. 1 ) taken along line  5 - 5  shown in  FIG. 1 .  FIG. 6  is a close-up portion of the serration array  144  on the crimp barrel  104  shown in  FIG. 5 . The serration array  144  in the illustrated embodiment extends a majority of the length of the crimp barrel  104  along the longitudinal axis  191  between the contact end  128  and the device end  130 . In an alternative embodiment, the serration array  144  may extend less than half of the length of the crimp barrel  104 , and the crimp barrel  104  optionally may include multiple serration arrays  144 . The serration array  144  includes multiple primary serrations  146  and multiple micro-serrations  148 . The primary serrations  146  and the micro-serrations  148  are both recesses defined along the interior side  138  of the crimp barrel  104 . The primary serrations  146  are formed by the primary ridges  208 A (shown in  FIG. 3 ), and the micro-serrations  148  are formed by the micro-ridges  208 B ( FIG. 3 ). Thus, the primary serrations  146  and the micro-serrations  148  are recesses that have generally the same shapes as the primary ridges  208 A and micro-ridges  208 B, respectively. The primary serrations  146  have larger sizes than the micro-serrations  148 , such that the primary serrations  146  are larger cavities than the micro-serrations  148 . 
     The primary serrations  146  have two side walls  166  and a bottom wall  168  between the side walls  166 . The side walls  166  may be tapered towards each other from the interior side  138  to the bottom wall  168  such that a width  152  of the primary serration  146  along the longitudinal axis  191  at the interior side  138  is greater than the width of the bottom wall  168 . In the illustrated embodiment, the primary serrations  146  have a trapezoidal cross-sectional shape, but the primary serrations  146  may have other shapes in other embodiments, such as rectangular, triangular, pentagonal, or the like. The micro-serrations  148  have two side walls  170  that taper towards each other with depth from the interior side  138  toward the exterior side  150 . In the illustrated embodiment, the micro-serrations  148  have a generally triangular shape such that the two side walls  170  meet at a point  172  of the micro-serration  148 . Alternatively, the side walls  170  may connect to a narrow bottom wall similar to the bottom wall  168  of the primary serrations  146  instead of meeting at the point  172 . 
     The width  152  of the primary serrations  146  along the longitudinal axis  191  at the interior side  138  is greater than a width  154  of the micro-serrations  148 . For example, the width  152  of the primary serrations  146  may be between two and ten times as wide as the width  154  of the micro-serrations  148 . The primary serrations  146  and the micro-serrations  148  have respective depths  156 ,  158  that extend from the interior side  138  towards the exterior side  150  of the crimp barrel  104 . The depth  156  of the primary serrations  146  is greater than the depth of the micro-serrations  148 . For example, the depth  156  of the primary serrations  146  may be two times as deep as the depth  158  of the micro-serrations  148 . The primary serrations  146  have a cross-sectional area  160  along the longitudinal axis  191  that is greater than a cross-sectional area  162  of the micro-serrations  148 . The cross-sectional areas  160 ,  162  are defined between the walls of the respective serrations  146 ,  148  and a plane  163  of the interior side  138 . For example, in an embodiment, the cross-sectional area  162  of a micro-serration  148  may be less than half, less than one-third, less than one-fourth, and/or less than one-fifth of the cross-sectional area  160  of a primary serration  146 . In an alternative embodiment, the depth  156  of the primary serrations  146  may be equal to or less than the depth  158  of the micro-serrations  148 , although the width  152  of the primary serrations  146  is greater than the width  154  of the micro-serrations  148  such that the cross-sectional area  160  of the primary serrations  146  is greater than the cross-sectional area  162  of the micro-serrations  148 . 
     In an embodiment, the primary serrations  146  and micro-serrations  148  in the serration array  144  are arranged with at least one micro-serration  148  between two adjacent primary serrations  146 . As used herein, adjacent primary serrations  146  refers to two primary serrations  146  that do not have any intervening primary serrations  146  therebetween, although there are intervening micro-serrations  148  between the adjacent primary serrations  146 . The serration array  144  may have an alternating sequence of primary serrations  146  and groups  174  of micro-serrations  148 . Each group  174  of micro-serrations  148  includes at least one micro-serration  148 . In the illustrated embodiment, each group  174  has at least two micro-serrations  148 , and some groups  174  have three micro-serrations  148 . The groups  174  and the primary serrations  146  alternate along the length of the array  144  between the contact end  128  and the device end  130  of the crimp barrel  104 . The array  144  in the illustrated embodiment includes three primary serrations  146  and four groups  174  of micro-serrations  148 . Each primary serration  146  is surrounded on each side (for example, on both a contact end-side and a device end-side) by a corresponding group  174  of micro-serrations  148 . In the illustrated embodiment, the serration array  144  includes a first primary serration  146 A, a second primary serration  146 B, and a third primary serration  146 C. The serration array  144  further includes a first group  174 A of multiple micro-serrations  148  that is disposed between the contact end  128  and the first primary serration  146 A, a second group  174 B of micro-serrations  148  that is disposed between the first and second primary serrations  146 A,  146 B, a third group  174 C of micro-serrations  148  that is disposed between the second and third primary serrations  146 B,  146 C, and a fourth group  174 D of micro-serrations  148  that is disposed between the third primary serration  146 C and the device end  130 . The array  144  may include different numbers and/or arrangements of the primary serrations  146  and the micro-serrations  148  in other embodiments. For example, in one alternative embodiment, one or both axial ends of the array  144  (most proximate to the contact end  128  and the device end  130 ) may be defined by a primary serration  146  instead of by a micro-serration  148 . 
     Since the primary serrations  146  are larger recesses than the micro-serrations  148 , two adjacent primary serrations  146  define a band  176  therebetween. Each band  176  is a portion of the crimp barrel  104  with sides defined by respective side walls  166  of the adjacent primary serrations  146 . The band  176  has a height along the vertical axis  193  that is generally equal to the height of the side walls  166  along the vertical axis  193 . At least some of the bands  176  include a group  174  of at least one micro-serration  148  thereon. For example, in an embodiment, each band  176  includes multiple micro-serrations  148  that are spaced apart from one another along the longitudinal axis  191 . Since there are three primary serrations  146 A-C shown in  FIG. 5 , the primary serrations  146 A-C define two bands  176 , with one band  176  on each side of the second, or inner, serration  146 B. The first and third primary serrations  146 A,  146 C are outer primary serrations along the length of the array  144 . Each of the outer serrations  146 A,  146 C defines a side of a corresponding band  176  on only an inner side of the respective outer serration  146 A,  146 C which faces towards the inner serration  146 B. The portions of the interior side  138  of the crimp barrel  104  along the respective outer sides of the outer serrations  146 A,  146 C, which face away from the inner serration  146 B, include at least one micro-serration  148  in the illustrated embodiment. Thus, micro-serrations  148  may be disposed on both sides of each of the primary serrations  146 . 
     The primary serrations  146  and the micro-serrations  148  define barrel teeth  180  between adjacent serrations  146 ,  148 . Some barrel teeth  180  are defined between two micro-serrations  148 , and other barrel teeth  180  are defined between one micro-serration  148  and one primary serration  146 . Each barrel tooth  180  has a top surface  182  and two sides extending from corresponding edges  184  of the top surface  182 . The sides of each tooth  180  are defined by the side walls  166 ,  170  of the respective serrations  146 ,  148  that define the corresponding tooth  180 . For example, the sides of a barrel tooth  180 A defined between two adjacent micro-serrations  148  are defined by two side walls  170  and may have equal heights along the vertical axis  193 . The sides of a barrel tooth  180 B defined between one primary serration  146  and one micro-serration  148 , on the other hand, may have different heights because one side is defined by a side wall  166  of the primary serration  146  and the other side is defined by a side wall  170  of the micro-serration  148 . The sides of the teeth  180  in the illustrated embodiment are tapered or sloped such that the teeth  180  have generally trapezoidal shapes, but the teeth  180  may have other shapes in other embodiments, such as rectangular shapes. The edges  184  of the barrel teeth  180  are configured to engage and scrape against the one or more electrical conductors  106  (shown in  FIG. 1 ) of the electrical device  102  ( FIG. 1 ) during a crimping operation to remove and/or displace an oxide layer to form metal-to-metal contacts. The serration array  144  in the illustrated embodiment includes 26 discrete edges  184 , but other amounts of teeth  180  and edges  184  may be formed in other embodiments. 
     In the illustrated embodiment, the top surfaces  182  of at least some of the barrel teeth  180  are concave. For example, the top surface  182  of a respective tooth  180  bows or curves towards the exterior side  150  of the crimp barrel  104  with distance along the width of the tooth  180  between the edges  184 . A middle portion  186  of the top surface  182  of a respective tooth  180  is located more proximate to the exterior side  150  than a proximity of each of the edges  184  of the tooth  180  to the exterior side  150 . The top surfaces  182  may be concave due to the pressing operation that forms the serrations  146 ,  148  in the interior side  138  of the crimp barrel  104 , as described above with reference to  FIG. 4 . The concave top surfaces  182  of the barrel teeth  180  allow the edges  184  to have relatively sharp angles, which may enhance the scraping of the edges  184  against the one or more electrical conductors  106 . The top surfaces  182  of the barrel teeth  180  may be relatively linear in an alternative embodiment. 
       FIG. 7  is a cross-sectional view of a portion of a terminal assembly  300  including the one or more conductors  106  of the electrical device  102  (shown in  FIG. 1 ) in the channel  132  of the crimp barrel  104  of the terminal  100 . In  FIG. 7 , the terminal assembly  300  is in a pre-crimped state.  FIG. 8  shows the terminal assembly  300  in a post-crimped state according to an embodiment, such that the crimp barrel  104  is compressed into mechanical engagement and electrical contact with the conductors  106 . Referring to  FIG. 7 , during a crimping operation a crimping apparatus compresses the crimp barrel  104  along the vertical axis  193  such that opposing portions  302 ,  304  of the crimp barrel  104  are forced inwardly into the channel  132  towards one another along respective crimping directions  306 ,  308 . The interior side  138  of the crimp barrel  104  engages and compresses the one or more conductors  106 , causing the metal of the conductors  106  to extrude (for example, flow, slide, or otherwise move) to regions of reduced pressure. Typically, the primary regions of reduced pressure are at the contact end  128  and the device end  130  (shown in  FIG. 8 ) of the crimp barrel  104 . Thus, during the crimping operation, the metal of the conductors  106  may flow in expanding directions  310 ,  311  towards the ends  128 ,  130 . 
     In an embodiment, the metal of the crimp barrel  104  may also flow in the expanding directions  310 ,  311  due to the compressive forces. For example, the crimp barrel  104  may be composed of one or more metals that have a relatively similar strength (or modulus of elasticity) as the one or more metals of the conductors  106 . The conductors  106  may be composed of a first metal material including at least one of copper or aluminum, and the terminal  100  may be composed of a second metal material that also include at least one of copper or aluminum. Optionally, the metal materials of the conductors  106  may be the same as the metal materials of the terminal  100 . Since the strength of the conductors  106  may be at least similar to the strength of the terminal  100 , there may be little differential metal flow between the crimp barrel  104  and the conductors  106  proximate to the interior side  138  of the crimp barrel  104  during the crimping operation, which limits the ability of the crimp barrel  104  to scrape against the conductors  106  to displace oxide layers and establish reliable metal-to-metal contacts. However, the serration array  144  is configured to utilize local areas of differential flow to enhance the scraping, even when the metal material of the terminal  100  is similar in strength to the metal materials of the conductors  106 . 
     As shown in  FIG. 7 , the primary serrations  146  define areas or pockets of reduced pressure. During the crimping operation, some metal of the conductors  106  proximate to the primary serrations  146  flows axially along opposite first and second directions  312 ,  314  towards the corresponding primary serrations  146  and at least partially fills the primary serrations  146 . As shown in  FIG. 8 , the metal of the conductors  106  fills each of the primary serrations  146  due to the compressive forces during the crimping operation. In an embodiment, as the metal of the conductors  106  proximate to the crimp barrel  104  flows in the first and second directions  312 ,  314  relative to the crimp barrel  104 , the edges  184  of the barrel teeth  180  along the interior side  138  of the crimp barrel  104  engage and scrape against the conductors  106 . For example, a segment of one conductor  106  disposed in engagement with the interior side  138  of the crimp barrel  104  along one of the bands  176  may be stretched in both directions  312 ,  314  towards the primary serrations  146  located on both sides of the band  176 . As the metal material of the conductor  106  is stretched, the edges  184  of the barrel teeth  180  along the band  176  (defined by the primary serrations  146  and the micro-serrations  148 ) scrape and wipe against the flowing metal material to remove and/or displace an oxide layer or other surface contaminants on the conductor  106 . The scraping provides a reliable metal-to-metal contact between the crimp barrel  104  and the conductor  106 , which supports the electrical conductivity of the resulting terminal assembly  300 . 
     Thus, the serration array  144  is configured to provide reliable metal-to-metal electrical contacts between the crimp barrel  104  and the one or more conductors  106 , even when there is little relative extrusion flow between the crimp barrel  104  and the conductors  106  due to a similarity in metal strength characteristics. Experimental testing has demonstrated that terminals  100  having the serration array  144  form terminal assemblies having more desirable electrical conductivity characteristics than some known terminals that do not include the serration array  144  described herein, such as lower initial resistance measurements, lower final resistance measurements after testing, and/or lower delta resistance measurements after testing at various terminal sizes. 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.