Abstract: The present invention relates to a stackable lamination for rotors of electric motors having inclined or helical slots, and a method for manufacturing the lamination. The lamination comprises at least one boss projecting from a face thereof for coupling with a second lamination in the same pack. The two coupled laminations are rotated according to an offset angle. Advantageously, a boss portion has a lower thickness than the remaining portions to allow the same boss to be coupled with a matching boss of the second lamination, the two coupled bosses being angularly offset according to a preset angle. The reduction in the boss thickness is carried out during the manufacturing step of the lamination.

Abstract: A method for attaching a capacitor to the feedthrough assembly of a medical device having a terminal pin comprises threading a first washer over the terminal pin, and placing a body of epoxy in contact with the first washer. The capacitor is positioned over the terminal pin such that the first washer and the body of epoxy are between the lower surface of the capacitor and a support surface. The body of epoxy is cured to couple the capacitor to the insulating structure. During curing, the body of epoxy is substantially confined between the upper surface and the lower surface by the ferrule, the insulating structure, the capacitor, and the first washer.

Abstract: A method of fabricating a multilayer wiring board proximity sensor includes forming a laminate, and fabricating a plurality of through-conductors through the layers of the laminate. The laminate has a plurality of layers including one or more core layers and a plurality of coil layers. Each core layer includes a core pattern formed of a permeable material, and each coil layer comprises at least one coil trace formed of a conducting material. Thus, the through-conductors may be fabricated through the layers of the laminate such that the coil traces are interconnected by the through-conductors to thereby form one or more coils disposed about at least a portion of the core patterns of the core layers.

Abstract: A method of manufacturing a stator core for a dynamo-electric machine by preparing a cylindrical laminated body by winding into a helical shape a continuous first sheet formed by press-punching from a strip-shaped first magnetic steel sheet material, preparing a plurality of second sheets by press-punching from a thicker second magnetic steel sheet material, bending the second sheets into an annular shape and stacking the second sheets bent into the annular shape on both axial ends of the laminated body and integrating the stacked sheets by laser welding.

Abstract: Embodiments of the present invention provide a thin-film coil assembly. The coil assembly includes a substrate, at least two layers of conductive material on top of the substrate, and one layer of insulating material between the two layers of conductive material, wherein the two layers of conductive material are in contact with two interconnects, respectively, which extends substantially vertical to the substrate.

Abstract: A method for assembling electrical windings about an axis, the windings being strips and wound in alternating strata with their widths parallel with the axis, includes the steps: (a) Winding a first-wound winding in a winding path about the axis establishing a first stratum. (b) Arranging the first-wound winding to clear the winding path. (c) Winding one or more next windings to establish next-wound windings in the winding path until at least one next stratum is established. (d) Interleaving earlier-wound windings to establish the plurality of strata; the interleaving including the steps of: (1) rearranging a next-to-be-wound winding to realign with the winding path; (2) winding the next-to-be-wound winding in the winding path until a next stratum is established; (3) arranging the next-to-be-wound winding to clear the winding path; and (4) repeating steps (d)(1) through (d)(3) until the assembling is complete.

Abstract: Disclosed is a magnetic recording medium and a method for manufacturing the same to provide a magnetic recording medium reducing medium noise and having excellent thermal stability. The magnetic recording medium includes a substantially amorphous seed layer and a polycrystal underlayer made of crystal grains having a substantially columnar structure, the polycrystal underlayer contacting thereto. In a boundary between the seed layer and the underlayer, fine grooves having a period up to as large as the magnetic layer crystal grain diameter are formed in the disc circumferential direction. Accordingly, the magnetic recording medium is allowed to have a grain shape with a value obtained by dividing the average grain diameter for the disc circumferential direction by the average grain diameter for the disc radial direction of no less than 0.5 and no more than 0.9, thus achieving simultaneously reduction of the medium noise and thermal stability.

Abstract: A method of manufacturing a motor that includes a permanent magnet unit disposed at a circumference for providing a plurality of magnetic poles, and a rotor disposed inside the circumference to be coaxial with the said permanent magnet unit. The rotor includes a center core coaxial with the center axis of the rotor, a plurality of coil cores disposed at peripheral portions of the rotors, and a plurality of concentrated coils respectively mounted on the coil cores. The method includes simultaneously: holding all of the coil cores by peripheral portions thereof so that outer peripheries of the held coil cores are on a prescribed circle, punching corners of one end of the center core to form chamfered corners; and moving the held coil cores from the end of the center core where the chamfered corners are formed so that the center core can be completely fitted to the held coil cores.

Abstract: An iron core of a rotating-electric machine and a manufacturing method for the same permit a uniform curvature to be easily obtained over an entire circumference of the iron core. The iron core has laminated magnetic plate strips, a cylindrical core proximal portion, a plurality of teeth projecting in a substantially radial direction from the core proximal portion, and slots for accommodating a winding that are located between the teeth adjacent to each other. The iron core is fabricated by curving both end portions of a substantially hexahedral laminate so that the core proximal portion obtains a predetermined curvature, forming the entire laminate into a cylindrical shape by wrapping it around a cylindrical core member so that distal ends of the teeth project from the core proximal portion, and joining both end portions of the laminate.

Abstract: Method for manufacturing an electromechanical sensor element for converting mechanical forces produced by the movements and vital functions or a person into electric signals, in which method a sensor film (11) is provided with metallic electrodes (15,16) placed on either side of it, at least one of said electrodes being a signal electrode, in which method is produced by cutting off a larger amount of sensor element material, in which method in the manufacture of sensor element material the electrodes are created in a continuous roll-to-roll process, and in which method the sensor element material is produced by laminating as a continuous roll-to-roll process. At least the sensor element material consists of repeated electrode patterns and a sensor element of a desired size and/or shape is formed by cutting the material between the patterns.

Abstract: A method of fabricating electrical core sheet assemblies such as transformer limbs, transformer yokes, and transformer cores, includes the steps of first cutting electrical core sheets, whose main surfaces have been provided with an anti-corrosion layer, into a desired shape. The side surfaces of the cut core sheets are first provided with an anti-corrosion layer, before the cut core sheets are assembled into the desired core sheet assembly.

Abstract: A mask frame assembly for evaporation includes a mask and a frame which supports the mask. The mask includes a metal layer having a predetermined pattern, and a coating layer which is formed on a surface of the metal layer so as to increase a precision of the predetermined pattern and a surface roughness of the mask.

Abstract: An armature manufacturing method of forming an armature including an arm holding a printing wire, and magnetic circuit forming members attached to the arm places the magnetic circuit forming members on the arm with a resistive layer of a resistive material having high electric resistance sandwiched between the arm and each of the magnetic circuit forming members, and welds together the arm and the magnetic circuit forming members with the resistive films sandwiched between the arm and the magnetic circuit forming members by spot welding. The arm and the magnetic circuit forming members of the armature can be joined together by welds having a high weld strength.

Abstract: The stacked core assembly apparatus, which can perform assembly at a high speed while keeping strength of an angle indexing apparatus, comprises a press machine 1, a non-synchronous transmitting apparatus 10 and an angle indexing apparatus 7. The non-synchronous transmitting apparatus 10 transforms a constant revolution of the press machine 1 into a variable revolution. The angle indexing apparatus 7 is connected to the non-synchronous transmitting apparatus 10 via a coupling device 20, and is connected to a rotatably stacking cavity device 51 of a press die 5. An accelerated rotational speed period of an output shaft 13 of the non-synchronous transmitting apparatus 10 is set during a Feeding-Phase period of time of the press machine 1, and thereby, a rotational state completion of a driving shaft 33 of the angle indexing apparatus 7 completes earlier than the Feeding-Phase period of time completion of the press machined 1 so that a non-rotating period of time can be provided.

Abstract: It is an object of the present invention to provide a method of manufacturing a rotor for an electric motor, in which displacement of the center of gravity is prevented. According to a feature of the present invention, a rotor for an electric motor comprises an inner core fixed to a rotating shaft of the rotor and multiple coil units respectively fixed to the inner core, wherein the coil unit has an outer core, a bobbin and a winding wound on the bobbin, and wherein weight of outer cores as well as winding units (the bobbin and the winding wound thereon) is respectively measured and stratified into several groups, necessary number of the outer cores and winding units are respectively picked out from the same stratified group and then such outer cores and winding units are assembled to the inner core.

Abstract: A stator is provided for an electrical device (e.g., a motor) comprised of one or more stator segments formed by the compaction of one or more powdered metallic materials. Each stator section has at least one tooth that forms a substantially toroidal path for magnetic flux entering and leaving the stator segment. Each stator segment also has a continuous insulated electrical winding that is associated with the stator segment such that a magnetic field is induced in the stator segment when a current is passed through the continuous insulated electrical winding. The current that is passed through the continuous insulated electrical winding of any one stator segment is not of the same electrical phase as the current that is passed through the winding of any adjacent stator segment.

Abstract: A method of making composite electric machine rotor assembly of a desired magnetic pattern. Magnetic segments and non-magnetic segments are separately formed to green strength, and then arranged adjacent to each other in a desired magnetic pattern. A small amount of powder material is added in-between the segments, and the whole assembly is then sintered to form a sinterbonded composite component of high structural integrity.

Abstract: A method of forming a stator core assembly for an electric machine includes providing a stator core having a plurality of radially extending slots, forming a flat wire pack having a plurality of continuous electrical wires, shaping the flat wire pack into a substantially cylindrical shape, and engaging the substantially cylindrically shaped flat wire pack with the stator core such that the continuous electrical wires are interlaced within the slots of the stator core.

Abstract: A method for fabricating a composite plate for a magnetic resonance imaging magnet. The method including cutting a starting plate having oppositely-directed major surfaces into a plurality of strips. Each of the strips having a width of approximately greater than 9 inches and faces which originally constituted parts of the major surfaces of the starting plate. The strips may be positioned to form the composite plate such that the width of each of the strips is equal to a thickness of the composite plate and the faces of the strips confront one another.

Abstract: In a method of manufacturing a rotor of an electric motor to be arranged inside a stator, a permanent magnet is formed in a ring-shape, and a rotating shaft and the permanent magnet are concentrically arranged in a mold. Then, a rubber material in a fluid state is poured into a space between the permanent magnet and the rotating shaft to vulcanize and mold a cushioning member having predetermined hardness. The permanent magnet and the rotating shaft are integrally coupled through the cushioning member.

Abstract: A method of manufacturing a layered core. The method includes the steps of: arranging a first plurality of yoke parts to define a first configuration magnetic pole sheet layer having first and second oppositely facing sides; arranging a second plurality of yoke parts to define a second configuration pole sheet layer having third and fourth oppositely facing sides; stacking the first plurality of yoke parts upon the second plurality of yoke parts so that the second side of the first configuration magnetic pole sheet layer is placed against the third side of the second configuration magnetic pole sheet layer; providing a circumferentially opening first female connector on a first yoke part; providing a first male connector on a second yoke part; and directing the first male connector into the first female connector.

Abstract: A method for manufacturing an armature including securing a core to the shaft having a plurality of slots extending in the axial direction formed on the outer circumferential surface thereof, forming a coil composed of a plurality of coil portions by simultaneously winding wires a plurality of turns around a pair of slots separated by a predetermined number of slots and offsetting each of the coil portions one slot at a time in the circumferential direction of the core, securing a commutator to the shaft having a plurality of segments, adjacent coil portions having a slot along one side thereof, and electrically connecting segments which should have the same electric potential by means of equalizing connectors so that each pairs of the segments that should have the same electric potential has a substantially equal electrical potential.

Abstract: A stator assembly that may be rounded into an annular form is disclosed that includes a plurality of stator segments where each stator segment defines a yoke portion and a stator tooth and a containment structure configured to position the stator segments relative to one another such that the stator segments do not physically touch one another and such that no magnetic circuit between adjacent stator segments is formed. Also disclosed is a method for forming a segmented stator, involving the steps of positioning a plurality of stator segment in a containment structure such that no magnetic circuit between adjacent stator segments is formed, forming a winding coil about at least some of the stator segments; and deforming the containment structure to form an annular stator and to establish a magnetic circuit between adjacent stator segments.

Abstract: A microphone assembly comprises a microphone, a connector secured to the underside of the microphone. A gasket has a sound collecting hole and is secured on the upper surface of the microphone.

Abstract: An amorphous laminated core and a method of making an amorphous laminated core by punching core pieces from amorphous thin sheet material, laminating the plural sheets of core pieces, and forming caulking through-holes by punching. Rod shaped materials are directed into the caulking through-holes of the laminated core pieces.

Abstract: In a method for manufacturing a solid core of laminations, a sheet metal web is cut in the longitudinal direction of the sheet metal web to produce at least two sheet metal strips. The sheet metal strips are separated in a direction transverse to the longitudinal direction of the sheet metal strips to form laminations. The laminations are joined to form a solid core. Joining can be carried out by welding, riveting, gluing or pressing.

Abstract: A method of manufacturing a stack of interlocked laminations in a progressive die assembly having a choke. A strip of sheet stock material is provided and a plurality of laminations are stamped therein. Each of the laminations include at least one interlock feature and include first and second regions and a connecting section extending between the first and second regions. The laminations are separated from the sheet stock material and stacked in the choke with the first and second regions in a first orientation. The laminations are also interlocked substantially concurrently with the separation and stacking of the laminations. The interlocked stack of laminations is removed from the choke with the first and second regions in their first orientation. The stack is then formed into a second shape wherein the first and second regions have a second orientation and the connecting section therebetween has been deformed.

Abstract: A process for producing bundles of laminated sheet metal for magnet cores, wherein laminations are punched free along two longitudinal edges of a sheet metal strip, at least two sheet metal laminations of a magnet core are of a different width extending from one longitudinal edge to the other, and several laminations, which rest against each other, are connected with each other to form the bundle. To simplify the tool control, the two longitudinal edges of a lamination are punched in edge cutting stations, which are separate from each other and are arranged offset in the feed direction of the sheet metal strip. The edge cutting stations for cutting the longitudinal edges have a cutting die and an associated bottom die. The cutting die, together with the bottom die, is displaced for creating different laminate widths.

Abstract: A rotor body according to the present invention comprises an annular laminated core of electromagnetic steel sheets defining therein a plurality of apertures in which permanent magnets are to be fixed, respectively, and a cylindrical core support to support the core, wherein the laminated core and the core support are joined to each other by brazing.

Abstract: Method for retrofitting an electric machine to reduce temperature rise therein. The method allows for removing at least a portion of an originally assembled coil support on a spider structure of the machine. The originally assembled coil support is configured to allow only axial flow to cooling air from a plurality of cooling vents in the armature of the machine. The method further allows for mounting a new coil support on the spider structure. The new coil support is configured to provide axial and radial routing to cooling air passing from the plurality of cooling vents. The air routed radially by the new coil support passes proximate the coil end turns and enables a reduction of temperature rise in the machine.

Abstract: The stacked core assembly apparatus, which can perform assembly at a high speed while keeping strength of an angle indexing apparatus, comprises a press machine 1, a non-synchronous transmitting apparatus 10 and an angle indexing apparatus 7. The non-synchronous transmitting apparatus 10 transforms a constant revolution of the press machine 1 into a variable revolution. The angle indexing apparatus 7 is connected to the non-synchronous transmitting apparatus 10 via a coupling device 20, and is connected to a rotatably stacking cavity device 51 of a press die 5.

Abstract: A bulk amorphous metal magnetic component has a plurality of laminations of ferromagnetic amorphous metal strips adhered together to form a generally three-dimensional part having the shape of a polyhedron. The component is formed by stamping, stacking and bonding. The bulk amorphous metal magnetic component may include an arcuate surface, and an implementation may include two arcuate surfaces that are disposed opposite each other. The magnetic component may be operable at frequencies ranging from between approximately 50 Hz and 20,000 Hz. When the component is excited at an excitation frequency “f” to a peak induction level Bmax, it may exhibit a core-loss less than “L” wherein L is given by the formula L=0.0074 f (Bmax)1.3+0.000282 f1.5 (Bmax)2.4, said core loss, said excitation frequency and said peak induction level being measured in watts per kilogram, hertz, and teslas, respectively.

Abstract: The invention relates to a method for the manufacture of a sensor element and to a sensor element. In the method, both surfaces of a sensor film are provided with metallic electrodes. The sensor element is produced by cutting it from a larger amount of sensor element material. In the manufacture of the sensor element material, the electrodes are produced as a continuous process from roll to roll and the sensor element material is formed by laminating as a continuous process from roll to roll. At least the signal electrode consists of repeated electrode patterns which are at least partially connected to each other via one or more narrow connecting strips, and a sensor element of a desired length and/or shape is produced by cutting the material across the region of the connecting strips.

Abstract: An inductor comprises a substrate comprising a semiconductor material, a first dielectric layer over the substrate, a magnetic layer over the first dielectric layer, a second dielectric layer over the magnetic layer, and a conductor over the second dielectric layer.

Abstract: A matrix type piezoelectric/electrostrictive (P/E) actuator includes a plurality of piezoelectric/electrostrictive elements, each including a piezoelectric/electrostrictive body and at least one pair of electrodes formed on a ceramic substrate. The matrix type P/E actuator is activated by the displacement of the piezoelectric/electrostrictive bodies. The piezoelectric/electrostrictive elements are joined to the ceramic substrate as respective unified bodies, and are two-dimensionally arranged independently from each other. The piezoelectric/electrostrictive actuator provides a greater displacement with a lower voltage, a high responsive speed, and a greater generating force, as well as enhancing the mounting ability and the integration. A method for manufacturing such a matrix type P/E actuator is also disclosed.

Abstract: A method and apparatus for assembling permanent magnet segments and a back ring wherein a fixture holds segments in circumaxially spaced relationship, adhesive is applied to the segments, externally from pressure sensitive adhesive tape and the fixture then expands to urge the segments into firm bonding engagement with the back ring.

Abstract: The present invention provides a method of manufacturing a magnetoresistive read head which reduces electrostatic discharge and allows measurement of gap resistances in the head.

Abstract: A method of connecting phases of a segmented stator electric machine includes providing a stator core. An end cap assembly is attached to the stator core. Winding wire is wound around the end cap assembly and the stator core to form a stator segment assembly. A plurality of the stator segment assemblies are assembled into a stator including first, second and third phases. A phase wire stitching machine is used to connect opposite ends of the winding wire of each of the stator segment assemblies to form the first, second and third phases of the stator. The phase wires can be attached to the stator segment assemblies using terminals, IDCs, hook terminals, and/or directly to the winding wire.

Abstract: The method of manufacturing rare earth thick film magnet comprising a step of forming an alloy layer of 30-100 ?m thick having a general formula RXBYTMZ on a substrate by a physical deposition process, and a step of heat-treating the alloy layer to form a thick film magnetic layer having R2TM14B phase as a main phase. In the general formula, R is at least one of rare earth elements, B is boron, TM is iron or its alloy partly substituted by cobalt. X is 0.1-0.2, Y is 0.05-0.2 and Z=1-X-Y. Further, the method of the present invention includes a step of laminating a plurality of alloy layers formed on a substrate together with the substrate. A motor comprising rare earth thick film magnet of the present invention is extremely small while obtaining high output.

Abstract: A motor stator core for achieving improved magnetizing feature in lower magnetic fields and reduced iron loss, and improving motor power. The stator core fabriated out of non-oriented electrical steel sheets is annealed by applying a magnetic field to the heated stator core at least in the temperature range from a temperature immediately above a Curie point thereof to 300° C. in the process of cooling the stator core. The magnetic field has the same direction as the direction of exitation of a stator in the motor when used to drive a motor. This increases the magnetic induction in lower magnetic fields in particular and reduces the hysteresis loss, with a reduction in the total iron loss of the stator. A motor using this stator core increases in saturation induction under exciting currents of higher frequncies, allowing enhanced motor power.

Abstract: A method of forming a stator for a brushless motor comprising providing a stator core having a generally rectangular body and having a plurality of teeth extending generally perpendicularly from a side of the body, and forming the stator core into a generally circular shape.

Abstract: A high frequency, low loss, power, laminated magnetic material includes alternating magnetic plates of low hysteresis loss material and electrically insulating films. The multi-layer structure allows for independently and simultaneously controlling and reducing hysteresis loss and eddy current loss, and maintaining a high resistivity, while operating at high frequencies and at high flux density levels, resulting in extremely low net loss density for the composite material. Methods of making this material include co-firing of the magnetic plates and thin insulating films, making the magnetic plates (of low hysteresis material, such as a ferrite) and insulating films separately, and using heat and/or pressure and/or adhesive or making a stack of magnetic plates with spacers in between them and dipping in a molten or liquid insulating material.

Abstract: A method of fabricating a piezoelectric/electrostrictive device including a driving portion, a movable portion, and a fixing portion for holding the driving portion and the movable portion. The driving portion includes a pair of thin plate portions facing each other, and a film-like piezoelectric/electrostrictive element formed on at least a part of the outer surface of at least one of the thin plate portions. A ceramic green laminate including at least one ceramic green sheet constituting one of the thin plates and at least one ceramic green sheet having at least one hole formed thereon is formed. The ceramic green laminate is sintered to produce a ceramic laminate. A piezoelectric/electrostrictive element is formed by a film formation method on the outer surface of the thin plate portion of the ceramic laminate. The ceramic laminate is then cut with the piezoelectric/electrostrictive element formed thereon.

Abstract: Non-linear inductor(s) are used to reduce the percent total harmonic distortion of the harmonics in the line currents in the input side rectifier system of an ac drive system. Several constructions for the non-linear inductor(s) are described. The non-linear inductor(s) may be constructed from E and I laminations. The gap depends on the construction of the middle leg of the E laminations and may have a step with a constant spacing or a variable spacing which depends on the stacking of the laminations. Alternatively the non-linear inductor(s) may be constructed from a toriodal core that either has a step gap or a variable type gap.

Abstract: A writing magnetic pole portion composed of a first magnetic film and a second magnetic film formed on the first magnetic film via a gap film is fabricated on a given wafer. Then, the writing magnetic pole portion is swung forward and backward around a rotation standard axis parallel to a center line of the writing magnetic pole portion in a direction parallel to a surface of the. Then, the writing magnetic pole portion is milled during the swing of the writing magnetic pole portion to define the width of the writing magnetic pole portion.

Abstract: A method for forming a spiral inductor (11) or component of a transformer, compatible with very large scale integrated processing, that achieves a higher Q value without occupying more space by splitting at least one turn (13 51) as two or more crisscrossing or interwoven smaller-width turns (13a 13b 52 53 54 55). The at least one turn (51) may, for example, be split into four turns paired up to provide two pairs of two turns, and the turns of each pair may then be interwoven or crisscrossed, and then the two pairs may also be interwoven or crisscrossed. The splitting of a turn into two or more smaller-width turns results in the current being divided among the smaller-width turns.

Abstract: An electric machine such as a direct current motor or generator in which a stator is formed using a set of electrically conductive blade structures disposed about an inner axis of a stator core. Electrical interconnections between the conductive blades are provided by a set of disks connected to the ends of the blades. The disks are formed preferably from an insulating substrate material having electrically conductive pads formed thereon to provide circuit interconnections between the blades. A desired path for current flow is provided by arranging the blades and conductive pads on the disks appropriately in the desired number of turns and phases. The conductive blades and conductive portions of the interconnect disks are formed, in a preferred embodiment, from a material such as a copper and molybdenum laminate.

Abstract: A method of making composite electric machine components. Magnetic segments and non-magnetic segments are separately formed to green strength, and then arranged adjacent to each other in a desired magnetic pattern. A small amount of powder material is added in-between the segments, and the whole assembly is then sintered to form a sinterbonded composite component of high structural integrity.

Abstract: A three-phase transformer and a method of its manufacture are presented. The transformer comprises a magnetic circuit and three coil blocks. The magnetic circuit comprises two spaced-apart, parallel, plate-like elements; and three spaced-apart, parallel column-like elementary circuits. Each of the column-like elementary circuits carries the corresponding one of the three coil blocks, and serves for the corresponding one of the three phases. The column-like elementary circuits are substantially perpendicular to the plate-like elements, and are enclosed therebetween such as to form a spatial symmetrical structure about a central axis of the transformer. Each of the column-like elementary circuits is substantially a toroid in the form of a multi-layer structure formed by winding a predetermined number N of packages of magnetic strips about a central axis of the toroid, each package being composed of a predetermined number n of layers formed by n strips placed on top of each other.

Abstract: An electrical machine using a plurality of separate teeth that can be axially inserted into a stator ring or armature after receiving a bobbin or form wound coil. Each tooth contains a primary locating structure and a secondary locating structure which respectively set the radial position and the angular position of the teeth in a stator ring. This construction can also be used with internal motor armatures. The primary and secondary locating structures have a size equal to or smaller than the portion of the tooth that holds the coil. This allows insertion of a pre-wound coil over these features without interference. The use of separate stator or armature teeth that are press fitted into the stator ring or armature allows the use of coil types that could not be inserted into a one piece stator or armature and tooth materials with optimum magnetic properties.