JPH02106909A - Manufacture of chip inductor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a chip inductor for preventing electromagnetic induction, which can be surface mounted on a substrate in a continuous and integrated process.

[Conventional technology]

A method of manufacturing a chip inductor for surface mounting, which has been conventionally used to prevent electromagnetic induction, is to obtain a ferrite paste If by thoroughly mixing and kneading powder of a ferromagnetic material such as ferrite, a binding resin, and a solvent such as water. This is laminated with films formed by a printing method or a doctor blade method, and dried to form a magnetic plate. A pattern is printed on this magnetic plate using a conductive material, and then another magnetic plate is laminated on top of the conductive plate to form a closed magnetic path. This is sintered and connected to the end of the conductive plate, and both cut ends are covered with conductive material. A chip inductor is formed which is covered with a cap and serves as an external electrode.

[Problem that the invention seeks to solve]

However, in general, in order to obtain a sufficient closed magnetic circuit in a chip inductor, it is necessary to prepare a tIi material plate using conventional printing methods.

This method has disadvantages in that it requires a large number of printing and drying steps and takes a long time, making it economically expensive. In addition, in the doctor blade method, since the green sheet film made of ferrite paste is thin, the number of lamination steps is large in order to obtain an aluminum body plate, which has the disadvantage that it cannot be manufactured at a low cost.

In addition, creating conventional ferrite paste not only requires a large amount of time to mix and knead the binding resin and solvent, but also automatically and consistently processes from the production of multiple chip inductor films to the cutting of individual elements. There is a drawback that it cannot be produced.

Therefore, there are many production steps and it is not possible to automatically obtain large quantities, which is economically disadvantageous.

[Failure to solve the problem]

The present invention eliminates such drawbacks of the conventional methods and has been developed by forming a ferrite paste by mixing and kneading a ferrite magnetic powder, a binding resin such as polyvinyl alcohol or ethyl cellulose, and a bath agent such as water into a press, roll processing using a roll, or extrusion molding. A bath agent is applied or sprayed on the joint surfaces of two strip-shaped Ti1 continuums, and while Ag-p
A raw inductance element is formed by inserting a strip-shaped conductive continuous plate extruded from a conductive paste such as A, stacking it under pressure, and cutting it before or after sintering. An inductance element is formed by providing an external terminal made of a conductive material. The same bonding resin and solvent are used for the band-shaped ferrite paste and conductor paste.

This is also a method for manufacturing a chip inductor formed by one multi-extrusion head, which includes an extrusion nozzle on the mantissa side for a strip-shaped continuous conductive plate, and space nozzles on both sides of the strip-shaped continuous magnetic plate.

[For production]

Therefore, in the present invention, the strip-shaped continuous conductive plate and magnetic continuous plate are continuously injection molded using multiple extrusion heads.
The entire process is done from overlapping, pressurizing, and cutting.

〔Example〕

An embodiment of the method for manufacturing a chip inductor of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the chip inductor element according to the present invention consists of two magnetic plates 1.
A conductive plate 2 cut from a strip in the same manner is superimposed and pressed between 1" and the cut magnetic plate 1, as shown in FIG. An inductance element is obtained.The magnetic plates 1 and 1' are prepared by pressing or calendering using a roll using a ferrite paste made by mixing and kneading ferrite magnetic powder, a binding resin such as polyvinyl alcohol or ethyl cellulose, and a solvent such as water. Alternatively, the conductive plate 2 may be formed by extrusion molding.Also, the conductive plate 2 may be formed by extrusion molding a conductive paste such as Ag-Pd paste.

Furthermore, the raw state impedance element is sintered to form a chip inductor, which is connected to the conductive plate 2 exposed on both end faces and provided with external electrodes 3 covering each end face by baking a conductive material. It is formed. Magnetic plate of this type of chip inductor 1. ? 1 operates to form a closed magnetic path for the current flowing through the conductive plate 2, and the individual chip inductors exhibit the same operation whether they are cut before or after firing.

Here, as shown in FIG. 4, a plurality of extrusion nozzles 6, 6', 61 are provided between two magnetic continuous plates 4, 4' extruded from ferrite paste.
A plurality of conductive continuous plates 5, 5° 51 injected from the wafer are sandwiched and overlapped and pressed together to obtain a band-shaped raw inductor element. Here, when the magnetic continuum is 4.4° superimposed and pressure-welded, mutual adhesion can be easily increased by spraying or applying a solvent such as water to one overlapping portion.

In addition, if the same bonding resin and solvent are used for the ferrite paste and the conductor paste, the wetting of the magnetic continuous plates 4, 4' and the conductive continuous plates 5゜5', 5'' will be good and the overlap will be good. can be easily improved.

In this process, as shown in FIG. 5, the ferrite paste as a whole is extruded and injected from the door to form band-shaped continuous magnetic plates 4, 4'.

Further, the conductive paste is injected from the extrusion head 7' to form a strip-shaped conductive continuous plate 5. These are sent out in the direction of arrow A, overlapped, and joined by pressure with roller 8, and then
A green inductor element is formed by cutting it vertically or horizontally with a cutter 9.

Further, in the manufacturing method of the present invention, as shown in FIGS. 6(a) and 6(b), a plurality of nozzles 6 for injecting conductive paste are provided in the center
, 6', 6'', and a molding head having space nozzles 10 for injecting ferrite paste wrapped around both sides of the molding head, a plurality of green inductor elements are obtained by one extrusion molding. A do 11 is formed into one multiple extrusion that allows for.

The integrated continuous process using this multiple extrusion head 11 is as shown in FIG.
Materials are put into each of the inductor elements, and a strip-shaped green inductor element is injection molded onto the conveyor 14 by a multiple extrusion head 11 provided at the front. This is cut with a cutter 9 to automatically produce a large number of raw inductor elements.

〔Effect of the invention〕

As described above, according to the present invention, the magnetic continuous plate 4 and the conductive continuous plate 5 of arbitrary thickness can be obtained by calendering using a press or roll, or by extrusion molding, and these continuous strips are A large quantity of green inductor elements can be obtained efficiently and economically through a consistent series of stacking, crimping, and cutting processes.

[Brief explanation of the drawing]

Figure 1 shows the temperature difference of ℃
2nd exploded external perspective view of the resulting raw inductor element
The figure is an external perspective view of a raw inductor element formed by pressure contact in Figure 1, Figure 6 is an external perspective view of a chip inductor with external electrodes provided on both end faces of Figure 2, and Figure 4 is an external perspective view of a raw inductor element. Fig. 5 is a perspective view of the structural appearance showing the outline of the vicinity of the extrusion head showing the manufacturing process of a continuous body in the form of a strip. Outline front view, showing
FIG. 6 is a multi-extrusion head that integrates extrusion heads for injection molding magnetic continuous plates and conductive continuous plates according to the present invention. Side view, Fig. 7 is a side view showing an outline of an integrated continuous extrusion processing machine using the multiple extrusion head shown in Fig. 6. Note that 1.1': VB root plate 2: conductive plate, 3,6° : External electrode, 4,4°: Ja continuous plate, 5,5',5° : Conductive continuous plate, 6,6',6'': Extrusion nozzle, 7°71:
Extrusion head, 8: roller, 92 vines. 10: Spatial nozzle, 11: Multiple extrusion head. 12: Extrusion molding machine, 13.13”: Input port. 14: Conveyor.

Claims (4)

[Claims] 1. A conductive material is placed between two strip-shaped continuous magnetic plates 4, 4' which are made by processing a ferrite paste made by mixing and kneading ferrite powder, a binding resin, and a solvent using a press or roll, or by injection molding using an extrusion head 7. A plurality of injection-molded conductive continuous plates 5, 5', 5'' are sandwiched and stacked and pressed together by a head 7', and cut into magnetic plates 1 before or after sintering.
, 1' and conductive plates 2 are laminated, and the conductive plates 2 are connected to both cut surfaces of the raw inductor element to form external electrodes 3, 3'. 2. 2. The method of manufacturing a chip inductor according to claim 1, wherein the solvent for improving mutual adhesion is applied or sprayed onto the joint surfaces of the continuous magnetic plates 4, 4'. 3. The plurality of conductive continuous plates 5, 5', 5'' are connected to the plurality of extrusion nozzles 6, 6', 6'' and the magnetic continuous plate 4.
, 4' are injection molded by a multi-extrusion head (11) comprising a spatial nozzle (10) including the nozzles 6, 6', 6''. 4. 2. The method of manufacturing a chip inductor according to claim 1, wherein the ferrite paste and the conductive paste are made of a bonding resin made of the same material or a solvent made of the same material, which improves the wettability and superposition of the bonding surfaces.