GB2222788A

GB2222788A - Coating electronic parts

Info

Publication number: GB2222788A
Application number: GB8920935A
Authority: GB
Inventors: Masaaki Okane; Kouzo Moriyasu; Hitoshi Nishimura
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 1988-09-17
Filing date: 1989-09-15
Publication date: 1990-03-21
Anticipated expiration: 2009-09-15
Also published as: GB2222788B; GB8920935D0

Abstract

An apparatus for applying coating fluid (P) to electronic parts (M), each having lead terminals (Mb), includes a drive (13, 14) for conveying a tape (T) carrying the electronic parts (M), an applicator (5) for applying the coating fluid (P) to a body (Ma) of each electronic part (M), and an edge (7) for removing hanging, excess coating fluid (Pa) applied to each electronic part (M). The removing edge (7) may be provided by a rod, wire or thread. The coating is applied by a V-grooved applicator roller (5) dipping in a tank (3) of coating fluid or by opposed spray nozzles (15 Fig 10). In the latter instance, opposed rollers (16 Fig 10) hold the tape (T) in the vicinity of the nozzles to prevent the electronic parts moving towards and away from the rollers. <IMAGE>

Description

APPARATUS FOR, AND METHOD OF, APPLYING COATING FLUID TO ELECTRONIC PARTS The present invention relates to an apparatus for, and a method of, applying coating fluid to electronic parts.

Fig. 1 of the drawings shows an electronic part M in the form of a capacitor having a pair of long lead terminals Mb extending from a disklike body Ma. Conventionally, a necessary amount of coating fluid is applied to the body Ma of such an electronic part M by using a coating apparatus as shown in Fig.

2, the coating becoming a cured outer film on the electronic part M. A plurality of electronic parts M arranged side by side are conveyed along a predetermined transport path in the direction of the arrow 'a' with the bodies Ma directed downwardly. Along the transport path of the electronic parts M there are provided an application station 1' for applying coating fluid P to the electronic parts M, and a removal station 2' for removing surplus coating fluid P from each of the electronic parts M.

The application station 1' includes a tank 3' containing the coating fluid P and an application roller 5' formed with a V-groove 4'. The applicator roller 5' is rotated such that a lower portion of the application roller 5' is dipped in the coating fluid P in the tank 3'. Meanwhile, the body Ma of each electronic part M is passed through the V-groove 4' at an upper position on the application roller 5'. The coating fluid P is held in the V-groove 4' of the application roller 5', and is applied to the electronic parts M passing through the V-groove 4'. An excess of the coating fluid P is applied to the electronic parts M, and surplus coating fluid P hangs down, as a hanging portion Pa, from a lower portion of the body Ma and is removed at the subsequent removal station 2'.

The removal station 2' includes a removal member 6' formed by a metallic plate. The removal member 6' is provided below the transport path of the electronic parts M. When the electronic parts M having the excess coating fluid P thereon are passed in contact with the upper face of the removal member 6', the surplus coating fluid P, i.e. the hanging portion Pa disposed at the lower portion of the body Ma, is scraped off and removed from the body Ma. Thus, the coating fluid P is applied to the electronic parts M at substantially uniform thickness. Subsequently, the coating fluid P applied to the electronic parts M is cured to form an outer coating film.

However, in the known method referred to above, it can happen that the body Ma with the coating fluid P on is directly rubbed against the removal member 6' thereby resulting in damage to the body Ma.

Furthermore, the known method has the disadvantage that since removed excess coating fluid P remains on the upper face of the removal member 6', the removal member 6' rapidly becomes unable to perform its function of removing surplus coating fluid P, this resulting in the need to replace the removal member 6' or to remove the coating fluid P from the removal member 6'.

Moreover, there is slight variation in the vertical positions of the electronic parts M passing the removal member 6'. Therefore, in the known method, when the removal member 6' is fixed at a certain position, coating fluid P is scraped off the bodies Ma more than necessary or insufficiently thereby resulting in inaccuracy of removal of the surplus coating fluid P from the bodies Ma.

Fig. 3 shows another prior art coating apparatus in which a plurality of electronic parts M are hung from a transport tape T by their lead terminals Mb, at a fixed pitch.

While the transport tape T carrying a number of the electronic parts M is being fed along a predetermined transport path, coating fluid is sprayed over the body Ma of each of the electronic parts M from a pair of spray nozzles 15 which are provided at opposite sides of the transport tape T in the course of the transport path of the electronic parts M.

Therefore, the coating apparatus of Fig. 3 eliminates the disadvantage of the known coating apparatus of Fig. 2 that the coating fluid P stored in the tank 3' or applied to the electronic parts M may be cured or deteriorated due to its contact with air. Hence, the coatingtapparatus of Fig. 3 has the advantage that coating of the electronic parts M can be performed without waste of the coating fluid P.

However, in the coating apparatus of Fig. 3, as the feed rate of the transport tape T is increased, vibrations of the transport tape T become large. Thus, the body Ma of each of the electronic parts M, which should be subjected to coating, swings sidewise with a large amplitude so that the distance between the body Ma and the spray nozzles 15 varies, so that the coating thickness on one side of the body Ma may become different from that on the other side of the body Ma. As a result, since the amount of coating fluid P applied to a base portion A (Fig. 1) of the lead terminal Mb becomes unstable, the outer appearance and the characteristics of the electronic parts M are adversely affected. Therefore, the coating apparatus of Fig. 3 has the disadvantage that since coating of the electronic parts M cannot be performed at a high speed, working efficiency is low.

According to this invention there is provided an apparatus for applying coating fluid to a series of electronic parts each having lead terminals, so as to form an outer coating film on each of the electronic parts, comprising a tape member for carrying the electronic parts; a drive means for conveying the tape member; an application means for applying coating fluid to a body of each of the electronic parts carried by the tape member; and a removal member providing an edge positioned for removing any hanging excess of the coating fluid applied to the body of each of the electronic parts.

Also according to this invention there is provided a method of applying coating fluid to electronic parts, comprising applying coating fluid to the electronic parts, and passing each coated electronic part relative to a removal member providing an edge positioned to remove any hanging excess coating fluid on each electronic part.

The invention provides an apparatus for, and a method of, applying coating fluid to electronic parts, in which any excess coating fluid applied to each of the electronic parts is removed from each of the electronic parts without damage to the electronic parts.

With the apparatus of the invention, when the electronic parts each having the coating fluid applied thereto are moved relative to the removal member, any hanging excess of the coating fluid is brought into contact with the removal member and is scraped off and removed from the electronic part. The removal member can be deflected by the electronic parts whereby only the excess coating fluid is removed from the electronic parts and the electronic parts are not damaged by the removal member. Furthermore, the removed coating fluid will not collect on the edge of the removal member.

The invention will now be described by way of example with reference to the drawings, in which: Fig. 1 is a front elevational view of a known electronic part (already referred to); Fig. 2 is a schematic front elevational view of a known coating apparatus (already referred to); Fig. 3 is a schematic perspective view of another known coating apparatus (already referred to); Fig. 4 is a schematic front elevational view. of a coating apparatus according to a first embodiment of the present invention; Fig. 5 is a fragmentary perspective view of the coating apparatus of Fig. 4; Fig. 6 is a view explanatory of operation of the coating apparatus of Fig. 4; Figs. 7a and 7b are front elevational views showing the vertical positioning of a removal member of the coating apparatus of Fig. 4; Fig. 8 is a top plan view of the removal member of Figs.

7a and 7b; Fig. 9 is a schematic top plan view of a coating apparatus according to a second embodiment of the invention; Fig. 10 is an enlarged fragmentary perspective view of the coating apparatus of Fig. 9; and Fig. 11 is an enlarged fragmentary side elevational view of the coating apparatus of Fig. 9.

Like parts are designated by like reference numerals throughout the drawings.

Referring now to the drawings, in Figs. 4 to 8, there is shown a coating apparatus K1 according to a first embodiment of the invention. In the coating apparatus K1, a number cf electronic parts M each having a body Ma to be subjected te outer coating are arranged side by side so as to be conveyed along a predetermined transport path in the direction of the arrow 'a' such that the body Ma is directed downwardly. Each of the electronic parts M has a pair of lead terminals Mb. The electronic parts M are conveyed by hanging the lead terminals Mb from a transport tape T. The transport tape T is displace in the direction of the arrow 'a' by feed rollers 13 and 14.

In the course of the transport path of the electronic parts M, an application station 1 for applying coating fluid P to the electronic parts M and a removal station 2 for removing surplus coating fluid P from each of the electronic parts M, are arranged along the transport direction of the electronic parts M.

The application station 1 includes a tank 3 containing the coating fluid P and an application roller 5 formed with V-groove 4. The application roller 5 is rotated so as to be partially dipped in the coating fluid P in the tank 3. The body Ma of each of the electronic parts M is passed through the V-groove 4 at an upper portion of the application roller 5 such that the coating fluid P is applied to the body Ma.

Otherwise the coating fluid P is applied to the body Ma by pouring the coating fluid P over the body Ma.

The removal station 2 comprises a removal member 7 arranged below the transport path of the electronic parts M and extending in a direction to intersect with the transport path of the electronic parts M. At station 1 an excess of the coating fluid P is applied to the electronic parts M, and surplus coating fluid P hangs down, as a hanging portion Pa, from a lower portion of the body Ma to be removed at the subsequent removal station 2. When the electronic part M passes the removal member 7, the hanging portion Pa of the coating fluid P is brought into contact with the removal member 7.

The removal member 7 has a diameter of 0.6 to 1 mm and is so vertically positioned as to either coincide with a lower end B of the electronic part M as shown in Fig. 7a or be downwardly spaced a small distance d from the lower end B of the electronic part M as shown in Fig. 7b. The removal member 7 is preferably formed by a single thread of plastics, for example Teflon (name used in trade and manufactured by Du Pont of the U.S.), polypropylene, polyethylene, etc. exhibiting poor adherence to the coating fluid P. The removal member 7 may also be formed by a metal wire or a rod. As shown in Fig. 8, the removal member 7 intersects with the transport tape T so as to form an angle of not more than 300 with the imaginary line L extending at right angles to the transport tape T.

With the above described coating apparatus K1, the body Ma of each electronic part M is passed through the V-groove 4 of the application roller 5 and thus, the coating fluid P is applied to an outer face of the body Ma. By movement of the transport tape T, the electronic part M having the hanging portion Pa is passed over the removal member 7. At the time of pass of the electronic part M over the removal member 7, the hanging portion Pa is brought into contact with the removal member 7 as shown in Fig. 6, so that the hanging portion Pa is scraped off by the removal member 7. Since the contact area between the removal 7 and the coating fluid P is small and the removal member 7 exhibits poor adherence to the coating fluid P, the coating fluid P scraped off by the removal member 7 falls down without adhering to the removal member 7.

The removal member 7 has elasticity and can be deflected vertically. Hence in the case where the body Ma of an electronic part M having the coating fluid P applied thereto is brought into contact with the removal member 7, the removal member 7 is deflected. As a result, the linear member 7 is not directly rubbed against the body Ma in such a manner as to damage the body Ma.

Furthermore, the removal member 7 has elasticity. Thus, even if there is slight scatter in the vertical positions of the electronic parts M, the removal member 7 is deflected in accordance with vertical positions of the electronic parts. In this deflected state, the removal member 7 scrapes only the hanging portion Pa of the coating fluid P off the body Ma, so that the coating fluid P is not scraped off the body Ma more than necessary.

In the apparatus described above the removal member 7 is fixed at the required location. However, a long or even endless removal member 7 can otherwise be used, which is fed longitudinally such that a portion of the removal member 7, which has scraped a hanging portion Pa off a body Ma, is not used again for scraping the next hanging portion Pa.

Although in the above described embodiment the electronic parts M are conveyed relative to a fixed removal member 7, it can otherwise be arranged such that the electronic parts M are fixed and the removal member 7 is laterally displaced relative to the electronic parts M.

The electronic parts to be coated are not restricted to radial type electronic parts as shown in the drawings but can be electronic parts of other types.

Referring to Figs. 9 to 11, there is shown a coating apparatus K2 according to a second embodiment of the invention. In the coating apparatus K2, the transport tape T is constituted by a base tape Ta and an adhesive tape Tb such that distal end portions of the lead terminals Mb extending from the body Ma of each of the electronic parts M are securely gripped between the base tape Ta and the adhesive tape Tb. The transport tape T having a number of the electronic parts M hung therefrom at a fixed pitch is disposed in a vertical orientation so as to be conveyed along a predetermined transport path between feed rollers 13 and 14 in the direction of the arrow 'a'.At predetermined positions in the course of the transport path of the transport tape T, spray nozzles 15a and 15b for spraying coating fluid P over the body Ma of each of the electronic parts M are provided at opposite sides of the transport tape T respectively, so as to confront opposite side faces of the body Ma.

Substantially immediately above the spray nozzles 15a and 15b, a group of three idle guide rollers 16a and a group of three idle guide rollers 16b are provided at opposite sides of the transport tape T respectively, so as to support the transport tape T with the transport tape T gripped between the guide rollers 16a and 16b. The guide rollers 16a and 16b are so disposed as to be alternately staggered with respect to each other along the transport tape T. As shown in Fig. 11, the guide rollers 16a and 16b are supported by an apparatus frame 17 so as to be disposed below the apparatus frame 17. One of the guide rollers 16a is disposed immediately above the spray nozzle 15a, while the remaining two guide rollers 16a are disposed above and opposite to the spray nozzle 15b through the transport tape T.Likewise, one of the guide rollers 16b is disposed immediately above the spray nozzle 15b, while the remaining two guide rollers 16b are disposed above and opposite to the spray nozzle 15a through the transport tape T.

The guide rollers 16a and 16b are mounted on ball bearings to ensure ease of rotation. Since the transport tape T is gripped between the guide rollers 16a and 16b, it is unlikely that the electronic parts M hung from the transport tape T will be urged rearwards by the pressure of the spray nozzles 15a and 15b.

Guide means for the transport tape T is not restricted to idle guide rollers 16a and 16b referred to above. A pair of guide rails may otherwise be used as the guide means. However, in this case, if the gap between the guide rails is made too small in order to maintain the vertical orientation of the transport tape T, frictional resistance between the transport tape T and the guide rails becomes extremely large, thereby possibly resulting in malfunction of the running of the transport tape T. On the other hand, if the transport tape T is supported by idle guide rollers 16a and 16b, frictional resistance leading to malfunction of running of the transport tape T is made quite small, so that the vertical orientation of the transport tape T can be sufficiently maintained even if the distance between the guide rollers 16a and 16b is made quite small.

As will be seen from the foregoing, in the coating apparatus according to the second embodiment of the invention, since the transport tape is gripped and supported adjacent the spray nozzles by the guide members, the vertical orientation of the electronic parts hung from the transport tape is secured stably, and the distance between the body of each of the electronic parts and the spray nozzles remains constant.

The vertical orientation of the transport tape is maintained stably without malfunction of running of the transport tape. As a result, since the spray coating of the electronic parts can be performed-by maintaining the distance between the spray nozzles and the body of each of the electronic parts constant, the thickness of the coating film on the opposite side faces of the body of each of the electronic parts is uniform and the coating fluid applied to each of the lead terminals is also uniform, so that the commerical value of the electronic parts based on their outer appearance can be improved and electrical characteristics of the electronic parts can be stablized.

Since the transport tape can be guided without malfunction of running of the transport tape, the running speed of the transport tape can be raised easily, thereby resulting in an improvement in productivity of the electronic parts.

Claims

1. An apparatus for applying coating fluid to a series of electronic parts each having lead terminals, so as to form an outer coating film on each of the electronic parts, comprising a tape member for carrying the electronic parts; a drive means for conveying the tape member; an application means for applying coating fluid to a body of each of the electronic parts carried by the tape member; and a removal member providing an edge positioned for removing any hanging excess of the coating fluid applied to the body of each of the electronic parts.

2. An apparatus as claimed in Claim 1, wherein the removal member is located to engage a lower end of the body of each of the electronic parts carried by the tape member.

3. An apparatus as claimed in Claim 1, wherein the removal member is located below a lower end of the body of each of the electronic parts carried by the tape member.

4. An apparatus as claimed in any preceding claim, wherein the application means comprises first and second spray nozzles for spraying coating fluid over each of the electronic parts, which are located at opposite sides of the transport tape respectively.

5. An apparatus as claimed in.Claim 4, including first and second guide members for supporting the transport tape, which are located substantially immediately above the first and second spray nozzles respectively, so as to grip the transport tape from opposite sides.

6. An apparatus as claimed in Claim 5, wherein the first guide member includes three first guide rollers and the second guide member includes three second guide rollers, the first and second guide rollers being so disposed as to be alternately staggered with respect to each other along the transport path of the electronic parts.

7. An apparatus as claimed in any preceding claim, wherein the removal member is a plastics material thread.

8. An apparatus as claimed in any one of Claims 1 to 6, where in the removal member is a metal wire or rod.

9. A method of applying coating fluid to electronic parts, comprising applying coating fluid to the electronic parts, and passing each coated electronic part relative to a removal member providing an edge positioned to remove any hanging excess coating fluid on each electronic part.

10. A method as claimed in Claim 9, wherein in a horizontal plane containing the removal member, the removal member forms an angle of not more than 300 with a line extending at right angles to the direction of movement of the electronic parts.