Abstract: A method of preparing an ophthalmic lens (20) for mounting in an eyeglass frame, the ophthalmic lens including a memory mark (28) that is situated on one of its ophthalmic faces (22) and that forms a code storing in digital form at least one item of information relating to a mechanical, geometrical, or optical characteristic of the ophthalmic lens. The method includes three steps: a) acquiring a raw image of at least a portion of the optical face of the ophthalmic lens on which an image of the memory mark appears; b) processing the raw image acquired in step a) in order to decode the information stored in the code; and c) centering and then shaping the ophthalmic lens as a function of the information decoded in step b).

Abstract: A substrate processing apparatus capable of accurately aligning a center of a substrate, such as a wafer, with an axis of a substrate stage and capable of processing the substrate without bending the substrate is disclosed. The substrate processing apparatus includes a first substrate stage having a first substrate-holding surface configured to hold a first region in a lower surface of the substrate, a second substrate stage having a second substrate-holding surface configured to hold a second region in the lower surface of the substrate, a stage elevator configured to move the first substrate-holding surface between an elevated position higher than the second substrate-holding surface and a lowered position lower than the second substrate-holding surface, and an aligner configured to measure an amount of eccentricity of a center of the substrate from the axis of the second substrate stage and align the center of the substrate with the axis of the second substrate stage.

Abstract: A head structure for a lapping assembly including a lapping control feature is disclosed. The lapping control feature includes a raised contact surface elevated from a front surface of the head structure of the lapping assembly. A relative position of the workpiece and raised contact surface are aligned to control workpiece thickness and other lapping parameters. In illustrated embodiments, the relative position of the workpiece and raised contact surface are aligned via an adjustment mechanism on the head structure. In illustrated embodiments, the adjustment mechanism is configured to adjust a position of the workpiece relative to the raised contact surface.

Abstract: The present invention relates to a carrier film for mounting a polishing workpiece. The carrier film comprises a surface substrate and a buffer substrate. The surface substrate consists of first elastomer, the first elastomer comprising a plurality of first holes; wherein the first holes have a drop shape, and each of the first holes has an opening. The buffer substrate consists of second elastomer, the second elastomer comprising a plurality of second holes. The surface substrate and the buffer substrate are adhered with adhesive comprising the first or the second elastomer. A method for making the carrier film is also provided. When polishing, the carrier film provides a good buffer property to conduct and release down force applied on the polishing workpiece.

Abstract: Embodiments of the present invention generally provide a load cup used in the transfer of substrates in a chemical mechanical polishing system. The load cup includes an improved substrate edge sensing mechanism to ensure a substrate is present and correctly positioned in the load cup for transfer to a polishing head. In one embodiment, a lever actuated edge sensing mechanism is provided. In one embodiment, the edge of a substrate contacts a lever, which contacts a sensor to detect that the substrate is present and correctly positioned for exchange with a polishing head. Embodiments of the present invention provide reliable detection, while reducing contact with the feature side of the substrate during substrate transfer.

Abstract: A setup platform is provided for a grinder including a cutoff wheel. The setup platform includes an upper planar surface including a first edge, which may be shaped similar to the grinder housing, the first edge including a slot therein for receiving the cutoff wheel. An anchor bar is mounted horizontally to the grinder housing, and a post extending from a lower surface of the setup platform is slidable on the anchor bar such that the setup platform is slidable relative to the anchor bar to removably mount the setup platform to the grinder such that the first edge is disposed adjacent the grinder housing and the cutoff wheel is received in the slot.

Abstract: A device for blocking workpieces for the processing and/or coating thereof, has a support surface for positioning the workpiece to be blocked, a blocking station in which the workpiece can be blocked on a blocking piece by a temporarily deformable blocking material, and a transport device which has a retaining head for the workpiece and by which a relative movement can be created between the workpiece being retained at the retaining head, and the support surface and the blocking station. The transport device has at least four position-controlled movement axes, by which to position the workpiece in a defined manner in consideration of the orientation and geometric information relative to a blocking piece located in the blocking station, and can be retained in the defined relative position to the blocking piece during blocking while leaving a blocking material accommodation gap between the workpiece and the blocking piece.

Abstract: A method for preparing a portion of a tire for repair includes the steps of providing a template having a pair of guide edges, securing the template to an interior surface of the tire, providing a tool for forming a discontinuity in the interior surface of the tire, forming a discontinuity in the interior surface of the tire, with the tool, along the guide edges of the template, and removing the template from the tire.

Abstract: A load cup apparatus for transferring a substrate in a processing system includes a pedestal assembly having a substrate support, an actuator, and a controller. The actuator is configured to move the pedestal assembly into a loading position in contact with a retaining ring of a carrier head and to generate a retaining ring thickness signal based on a distance travelled by the pedestal assembly. The controller is configured to receive the retaining ring thickness signal from the actuator.

Abstract: Embodiments of the present invention generally provide a load cup used in the transfer of substrates in a chemical mechanical polishing system. The load cup includes an improved substrate edge sensing mechanism to ensure a substrate is present and correctly positioned in the load cup for transfer to a polishing head. In one embodiment, a lever actuated edge sensing mechanism is provided. In one embodiment, the edge of a substrate contacts a lever, which contacts a sensor to detect that the substrate is present and correctly positioned for exchange with a polishing head. Embodiments of the present invention provide reliable detection, while reducing contact with the feature side of the substrate during substrate transfer.

Abstract: A chemical mechanical polisher comprises a polishing platen capable of supporting a polishing pad, and first and second substrate carriers that are each capable of holding a substrate against the polishing pad. First and second slurry dispensers, each comprise (i) an arm comprising a pivoting end and a distal end, (ii) at least one slurry dispensing nozzle on the distal end, and (iii) a dispenser drive capable of rotating the arm about the pivoting end to swing the slurry dispensing nozzle at the distal end to dispense slurry across the polishing platen.

Abstract: A cylindrical grinder is disclosed that includes a support unit including an upper support device and a lower support device, in which an ingot of silicon single crystal is interposed in a direction of axis line between the upper support device and the lower support device and is clampingly held to be rotated around the axis line, and a grinding unit that relatively moves along the direction of axis line of the ingot to traverse grind an outer circumference of the ingot. The upper support device is placed at an upper position and the lower support device is placed at a lower position, so that the support unit clampingly holds the ingot in a state in which the direction of the axis line of the ingot is disposed along a vertical direction.

Abstract: A method of grinding the tip of a blade which forms part of a rotor for a gas turbine engine is provided. The method includes mounting a plurality of blades in a disc to provide a blade assembly; mounting the blade assembly in a grinding apparatus; aligning the plurality of blades in a predetermined position using compressed fluid; and, grinding the blade tips.

Abstract: The present invention relates to a sheet for mounting a workpiece and a method for making the same. The method includes the steps of: (a) providing a sheet body having a top surface, a bottom surface, at least one side surface and a plurality of pores, wherein some of the pores open at the side surface; and (b) sealing or narrowing the pores that open at the side surface. Since the pores that open at the side surface are sealed or narrowed, the slurry is prevented from entering into the interior of the sheet body. Therefore, the infiltration distance reaches a predetermined value slowly, thereby increasing the effective life of the sheet.

Abstract: A slide holder for mounting to a sample holder having a pair of openings therein, for a grinder/polisher includes a plate for receiving the slide. The slide holder includes a pair of stems extending from the plate and configured and spaced for receipt in the sample holder openings. A locking element is mounted to each stem. The locking elements are mounted to pivot eccentrically relative to a center axis of each stem. The stems are inserted into the sample holder openings and the locking elements are pivoted to lock the slide holder to the sample holder and to prevent the stems from disengaging from the sample holder.

Abstract: A roll grinding apparatus includes a clamping device, a grinding wheel, a first driver, and a second driver. The clamping device includes a base, a support connected with the base and being movable relative to the base, a first clamping member and a second clamping member coupled to the first clamping member. The first clamping member and the second clamping member are rotatably mounted on the support for cooperating to clamp the workpiece. The first clamping member and the second clamping member are movable relative to the grinding wheel by movement of the support relative to the base so that the rotary axes of the first and second clamping members are adjusted to be parallel to a central axis of the grinding wheel. The first driver is connected with the first clamping member. The second driver is connected with the second clamping member.

Abstract: An adhesive tape, interposed between a lens to be processed and a holding jig when the lens is mounted in a lens processing machine, which has a plastic foam with holes opening in an adhering surface and an adhesive layer formed on the adhering surface of the plastic foam, and having a suction function for providing suction to the adhering surface together with elastic restoration after the plastic foam is deformed under compression. The adhesive tape of the present invention also exhibits sufficient shear adhesive strength in relation to a lens that has received surface processing and can realize precise lens processing.

Abstract: An object holding apparatus for holding an object, a portion of which is supposed to be surface treated, the object holding apparatus including: a body to which the object is fixed; a mask for covering a non-treatment portion of the object; and a magnetic fixing member for bringing the mask into close contact with the object by magnetic force. The body includes an engagement member for engaging with the object, thereby positioning the object.

Abstract: Retaining rings are presented with specially designed inserts that increase rigidity and improve heat dissipation. Inserts that are more rigid, and that have better ability to conduct heat, are inserted into pockets positioned along the outer portion of the rings. The pockets do not compromise the upper, lower or inner portion of the rings. Because the inserts are more rigid than the material used in the body of the ring, they absorb the deforming forces resulting from fastening the ring to the carrier head. Because they are better conductors than the material used in the body of the ring, the ring is better able to dissipate heat generated during polishing. Moreover, because the inserts are positioned in the outer portion of the ring, the inserts are not exposed to the polishing surface during polishing and therefore are less likely to react undesirably with the chemicals used during polishing.

Abstract: A loading device of chemical mechanical polishing (CMP) equipment for processing semiconductor wafers is provided. The loading device includes a loading cup having a cup-like bath, a cup plate installed in the bath, and a loading plate supported on the cup plate for absorbing shock and seating the wafer. A driving device and a driving shaft horizontally pivot and vertically move the loading cup between a platen of a polishing apparatus and a spindle. An arm connects the loading cup and the driving shaft. At least one through hole is located in a mutually corresponding position of the bath, the cup plate, and the loading plate of the loading cup. A probe assembly optically detects a polished thickness at a polished point on the wafer.

Abstract: A cup attaching apparatus for attaching a cup to an eyeglass lens, comprises: a lens mount on which the lens is to be mounted; at least three support pins provided on the lens mount to support the lens when a rear refractive surface of the lens is brought in contact with the support pins; a holding unit adapted to hold the support pins so that a supporting plane defined by the support pins is inclinable; a lens clamp for clamping the lens in cooperation with the lens mount when the lens is mounted on the lens mount; at least three presser pins provided on the lens clamp to clamp the lens when a front refractive surface of the lens is brought in contact with the presser pins; and a locking unit adapted to keep the supporting plane defined by the support pins in a substantially horizontal position when the lens is not clamped between the lens mount and the lens clamp.

Abstract: A device or tool setter has the purpose of setting the position of a support bar, adjustably connected to a grinding machine, in relation to a rotatable grindstone of the machine for obtaining a desired edge angle of a tool supported for grinding by the support bar. The device is provided with discs for defining two contact points with the grindstone and a hole for connection to the support bar.

Abstract: A wafer substrate is polished by disposing the wafer substrate between an abrasive cloth on a polishing platen and a plate, and relatively rotating the polishing platen and the plate for mirror polishing the surface of the wafer substrate with the abrasive cloth. A liquid is fed onto the plate side surface of the wafer substrate so that the wafer substrate is directly held to the plate by the adsorption force of the liquid, while performing the mirror polishing.

Abstract: A loading device of chemical mechanical polishing (CMP) equipment for processing semiconductor wafers is provided. The loading device includes a loading cup having a cup-like bath, a cup plate installed in the bath, and a loading plate supported on the cup plate for absorbing shock and seating the wafer. A driving device and a driving shaft horizontally pivot and vertically move the loading cup between a platen of a polishing apparatus and a spindle. An arm connects the loading cup and the driving shaft. At least one through hole is located in a mutually corresponding position of the bath, the cup plate, and the loading plate of the loading cup. A probe assembly optically detects a polished thickness at a polished point on the wafer.

Abstract: A lens element has an annular flange portion which has a tapered lateral surface so as to form at least an annular clearance tapering from a rear edge thereof when it is received in a lens holder. An adhesive which is partly filled in the clearance curs in wedge-shape to secure the lens element to the lens holder, and besides forming wedges by which the lens element is forced and held in an axial direction so as thereby to prevent the lens element from falling out of the lens holder even if the adhesive exfoliates from either one or both of the lens element and the lens holder.

Abstract: The present invention relates to a load cup configured to speed up substrate transferring to and from a carrier head and to reduce corrosion during the transferring. One embodiment of the present invention provides a non-contact substrate holder comprising a pedestal having a top surface configured to support a substrate, and at least one injection port configured to eject a high velocity liquid stream on the top surface of the pedestal, wherein the liquid stream in configured to secure the substrate on the pedestal without the substrate contacting the top surface of the pedestal.

Abstract: The present invention relates to a carrier film for mounting a polishing workpiece. The carrier film comprises a surface substrate and a buffer substrate. The surface substrate comprises holes, and the material of the surface substrate comprises elastomer. The buffer substrate comprises holes, and the material of the buffer substrate comprises the elastomer. The surface substrate and the buffer substrate are adhered with adhesive comprising the elastomer. A method for making the carrier film is also provided. When polishing, the carrier film provides a good buffer property to conduct and release down force applied on the polishing workpiece.

Abstract: A sharpening device for the blade of a tool such as a chisel or plane is in two parts. The first is a jig into which the blade is inserted with its tapered end projecting some distance beyond the jig. This distance is related to the angle to which the blade is to be sharpened. The second part is a marked reference member which is brought into a position alongside the jig. The blade is advanced through the jig until its tip reaches a marking on the reference member corresponding to the required sharpening angle for the tool. The tool is then clamped in the jig. The jig incorporates a roller which rolls on the sharpening stone while the tapered tip of the blade is sharpened by contact with the stone.

Abstract: A cup attaching apparatus for attaching a cup, used during processing of an eye glass lens, to the lens, the apparatus includes: a placing portion onto which the lens is placed; a holding portion for detachably holding the cup; a supporting portion for supporting the holding portion; a moving mechanism for moving the supporting portion in an optical axis direction of the placed lens; and a pressure regulating mechanism for preventing a cup attaching force from exceeding a predetermined pressure.

Abstract: There is disclosed a block piece for holding an optical workpiece, in particular a spectacle lens, for machining thereof, which block piece comprises a basic body which has an end face, against which the workpiece can be blocked by means of a temporarily deformable material, and a clamping face via which the workpiece blocked on the basic body can be fixed on a spindle of a machining machine. According to the invention, the basic body is injection-molded from plastic and is provided on its end face with at least two cut-outs for receiving the temporarily deformable material, said cut-outs being arranged on either side of an imaginary plane which contains the central axis of the basic body, and the boundary face of said cut-outs which is closest to the central axis of the basic body in each case forms an undercut.

Abstract: A holder for an optical fiber ferrule end face grinding apparatus is provided which can grind an increased number of optical fiber ferrules simultaneously. The holder comprises a holder plate provided with a plurality of ferrule insertion holes, a seat extending to at least one insertion hole and having a first wall, and a second wall on a side of the insertion hole opposing the seat. A slidable holding member including a front face facing the second wall, and an inclined rear face is disposed on the seat. A depression member is mounted on the holder plate that presses downwardly on a rod member disposed on the inclined rear face. As the depression member is operated, the rod member is pressed downwardly along the first wall, and the holding member is pushed forward such that a ferrule is clamped between the front face and the second wall.

Abstract: A direct clamp robotic finishing system is provided including a robot, a gripper secured to the robot, and a pair of fingers secured to the gripper. A tray assembly is also provided for supporting a plurality of implants for picking up by the fingers. An implant reorientation station is provided for supporting the implant being maneuvered by the robot as the robot re-grips the implant from a new direction. The fingers directly clamp the implant thereby eliminating the need for dedicated implant support bars.

Abstract: A method of blocking ophthalmic lenses for edging comprises providing an ophthalmic lens having first and second surfaces, providing a first block for securing against the first lens surface and a second block for securing against the second lens surface. The method then includes placing an adhesive layer on the first block, placing a film having cling properties between the adhesive layer and the first lens surface, and urging the first block toward the first lens surface and the second block toward the second lens surface. The film having cling properties provides sufficient bonding force between the adhesive layer and the first lens surface to prevent the ophthalmic lens from slipping in the blocks during edging thereof.

Abstract: Fabrication techniques for polishing fibers engaged in grooves on substrates. A protection template assembly is disclosed to protect the unpolished portions of fibers. Chemical mechanical polishing may be used to achieve high fabrication throughput and high polishing uniformity. Optical monitoring may be used to monitor the polishing in real time.

Abstract: A lens blocking device is disclosed that includes a frame, a light source mounted on the frame, a carriage having a first end and a second end mounted on the frame for sliding movement between first and second positions, a first mirror mounted on the carriage first end and a lens block holder mounted on the carriage second end and shiftable between third and fourth positions with respect to the carriage, a stage disposed between the light source and the carriage, and including an opening, for supporting an object, an at least partially translucent screen generating a display image operably connected to the support frame, at least one second mirror arranged to reflect an image of an object on the stage from the first mirror, when the carriage is in the first position, onto the screen, and an actuator operably connected to the carriage.

Abstract: Retaining device (1) for a block or suction element (10) in a centering device for spectacle lenses, having a support, which has a longitudinal axis (2), having a spherically dome-shaped bearing surface (3) on the support, having a spherical dome (5), which is mounted cardanically on the support and is complementary to the bearing surface, having a holding element (6) in the spherical dome for the block or suction element with a contact surface (11) for the spectacle lens, and having a radius (R) of the bearing surface and of the spherical dome, the mid-point (M) of which is located on the longitudinal axis of the support (1) on the contact surface for the spectacle lens.

Abstract: A gas turbine component blank is shaped by clamping the gas turbine component blank into a fixture that accurately positions the gas turbine component blank in three dimensions. The positioning is accomplished against stops accurately machined into a base of the fixture, by first supporting the gas turbine component blank on one set of stops that prevents movement in the direction perpendicular to a plane of the base, and then operating a movable clamp to force the gas turbine component blank against other sets of stops that limit the movement of the gas turbine component blank in directions lying in the base plane. The clamp has a compound movement that simultaneously forces the gas turbine component blank against stops that prevent movement in orthogonal directions lying in the base plane. The gas turbine component blank is thereafter shaped, preferably by grinding the sides of the root precursor of the gas turbine component blank.

Abstract: A polishing puck assembly is provided for use in polishing a fiber optic connector. A slidable weight rests on the fiber optic connector to urge the ferrule of the fiber optic connector to extend below a bottom surface of the puck assembly. The puck assembly can be manipulated relative to polishing material to polish the end of the fiber optic connector. The polishing material can be circular in shape and held by a palette defining one or more circular pockets for holding the polishing material. Different polishing material can be positioned in the different pockets. A circular guide can be utilized in the circular pocket wherein the guide includes a circular opening with a center offset from a center of the circular guide.

Abstract: A method of lathing a lens, especially a contact lens, involves attaching the cylindrical blank of lens material to a first block of machineable plastic material, lathe cutting a desired first lens surface in the cylindrical blank, attaching the machined first lens surface of the blank to a second block, lathe cutting to remove the block of machineable plastic material, and lathe cutting a desired second lens surface in the blank. Both the first and second blocks may be adhered to the lens blank with an adhesive curable by ultraviolet radiation, and a two-piece block, composed of a head section and a body section, is disclosed.

Abstract: A polishing method and polishing apparatus capable of improving the flatness of a wafer are provided. When a wafer is adhered to a wafer holding plate for polishing a surface to be polished of the wafer by pressing and rubbing the surface to be polished against a polishing pad on a polishing turn table, the wafer is held by vacuum-chucking the surface to be polished of the wafer such that a surface to be adhered of the wafer forms a convex surface in a vicinity including an arbitrary point in the surface to be adhered within a region surrounding a center of the surface to be adhered of the wafer, and the region being at least not less than 50% of an entire adhesion area; and the wafer is adhered to the wafer holding plate from a central portion of the surface to be adhered of the wafer.

Abstract: A chemical mechanical polish apparatus comprises a platen having a polishing pad thereon, a wafer carrier holding a wafer on the polishing pad, and a pusher. The pusher has a base disk and at least two guiding structures at the rim of the base disk. Each guiding structure has a shell with an opening, an elastic device and a pin moving through the opening, wherein the opening is non-linear.

Abstract: A load cup for transferring a substrate in a chemical mechanical polishing system is provided. In one embodiment, a load cup for transferring substrates in a chemical mechanical polishing system includes a substrate support having a first side adapted to support a substrate thereon and at least one actuator coupled to the substrate support and adapted to move the substrate support laterally. In another embodiment, a method for transferring a substrate between a polishing head and a load cup includes sensing a position of the polishing head relative to the load cup and automatically aligning the load cup and polishing head in response to the sensed relative position.

Abstract: A holder for an optical fiber ferrule end face grinding apparatus is provided which can grind an increased number of optical fiber ferrules simultaneously. The bolder comprises a holder plate provided with a plurality of ferrule insertion holes, a seat extending to at least one insertion hole and having a first wall, and a second wall on a side of the insertion hole opposing the seat. A slidable holding member including a front face facing the second wall, and an inclined rear face is disposed on the seat. A depression member is mounted on the holder plate that presses downwardly on a rod member disposed on the inclined rear face. As the depression member is operated, the rod member is pressed downwardly along the first wall, and the holding member is pushed forward such that a ferrule is clamped between the front face and the second wall.

Abstract: Fabrication techniques for polishing fibers engaged in grooves on substrates. A protection template assembly is disclosed to protect the unpolished portions of fibers. Chemical mechanical polishing may be used to achieve high fabrication throughput and high polishing uniformity. Optical monitoring may be used to monitor the polishing in real time.

Abstract: A device for sharpening ski edges and the like which is useful in sharpening both the side and bottom edges of skis is disclosed. The device is operable easily by an individual, is portable and allows a bevel to be sharpened into the edge where desired quickly and easily.

Abstract: A grinding wheel machine bracket comprises a fixations eat having a long through hole to receive a screw for fastening the fixation seat with a grinding wheel machine. The fixation seat has a pivoting seat with an axial hole, and a pointer located at the top thereof. A bracket seat is provided with a loading surface, a threaded hole, and an arcuate shoulder plate located over the threaded hole. A threaded rod is engaged with the threaded hole of the fixation seat via the axial hole. The bracket seat is changed in angle in relation to the fixation seat so as to adjust the angle of the loading surface of the bracket seat in relation to the grinding wheel of the grinding wheel machine. The bracket seat is fixed by the threaded rod at an angle so set.

Abstract: A process for forming a semiconductor wafer which is single side polished improves nanotopology and flatness of the polished wafer. The process reduces the effect of back side surface features, such as edge ring phenomena and back side laser marks, on nanotopology, thereby improving oxide layer uniformity for chemical/mechanical planarization (CMP) processing, and flatness on the polished front side of the wafer after polishing. The wafer is mounted on a polishing block by wax. The edge ring causes certain deformation and stress in the wafer upon mounting, which is held by the wax. After mounting, the wax is heated to allow the wafer to relax, removing the stress, without degrading the bond of the wafer to the polishing block. The wafer is polished and removed from the polishing blocks. The polished surface substantially retains its shape after being de-mounted from the block.

Abstract: A repair machine for compact disk is used for cleaning, maintaining, and repairing compact disks. The processing procedure is basically a mechanical method by: placing a scratched compact disk on a CD turntable of the repair machine, grinding it with a grinding wheel and dripping grinding agent on the grinding wheel continuously. The grinding agent is classified in three categories: coarse, middle, and fine (polishing), for trimming scratch to renew a marred compact disk.

Abstract: A method of lathing a lens, especially a contact lens, involves attaching the cylindrical blank of lens material to a first block of machineable plastic material, lathe cutting a desired first lens surface in the cylindrical blank, attaching the machined first lens surface of the blank to a second block, lathe cutting to remove the block of machineable plastic material, and lathe cutting a desired second lens surface in the blank. Both the first and second blocks may be adhered to the lens blank with an adhesive curable by ultraviolet radiation, and a two-piece block, composed of a head section and a body section, is disclosed.

Abstract: An apparatus for simultaneously or selectively grinding ends of a plurality of optical fibers held by optical fiber end devices such as connectors including ferrules. The apparatus has a holder plate having a plurality of types of supporting structures for fixing and supporting a plurality of types of optical fiber end devices with optical fibers connected thereto. Spring or weights are used for urging ends of the optical fibers on the optical fiber end devices supported by the supporting structures. A circular-path-based relative motion is caused to occur between the holder plate and the grinding plate. Each of the optical fiber end devices is a connector including a ferrule. In such a case, the plurality of types of optical fiber end devices may be connectors whose end surfaces are to be ground at different angles or may be the connectors of different connection types.