PARTS MOUNTING METHOD

Abstract: In a parts mounting method having plural parts feed units, for setting aside a parts feed unit at a refill position if running short of a certain part in the process of mounting parts, and continuing parts mounting in other parts feed units, it is intended to reduce production stops due to parts shortage, and enhance the operation rate of the mounting machine. To achieve the object, the method of the invention comprises a step of judging if parts are refilled in the parts feed unit 4R at the refill position when parts shortage occurs while mounting parts in the parts feed unit 4L, a step of judging if all parts feed units 4L, 4R are out of the parts which are in shortage if parts are not refilled, and a step of mounting parts from the parts feed unit 4R at the refill position if shortage parts are present in the parts feed unit 4R at the refill position.

Description: The present invention relates to a parts mounting method by a mounting machine. Recently, along with the advancement of electronics revolution, further enhancement of productivity is also required in electronic parts mounting machines. JP-A-04 219000 describes a parts mounting machine equipped with a main supply unit and an auxiliary supply unit. Parts are mounted from the main supply unit until a part therein is in shortage. In this case, the main supply unit is exchanged for the auxiliary supply unit until the main supply unit is refilled. JP-A-07 162194 suggests to equip a parts mounting machine with a main part supply unit and a sub-part supply unit. Parts are mounted from the main part supply unit until a part therein is in shortage. In this case, the specific part which is in shortage in the main part supply unit is supplied from the sub-part supply unit. Conventional electronic parts mounting machines are described below while referring to Fig. 2, Fig. 3, and Fig. 4. Fig. 2 shows a schematic constitution of an electronic partsmounting machine. Reference numeral 1 denotes a rotary head, which mounts parts by means of plural nozzles 2. Reference numeral 3 denotes an X-Y table, which fixes a board to mount parts on, and positions the board beneath the nozzles 2. Reference numerals 4L, 4R are parts feed units, and plural parts cassettes (parts feed means) 5 are mounted on each one thereof, and desired parts cassettes are positioned beneath the nozzles 2. Reference numeral 7 denotes a controller, which controls the entire electronic parts mounting machine. Reference numeral 10 is an indicator warning the shortage of parts to the operator, 11 is board carrying means, and 12 is board discharge means. Referring now to Fig. 3, the operation of parts feed units 4L, 4R (hereinafter shown merely as L and R) is described. Fig. 3 (a) shows the configuration of parts cassettes 5 in the parts feed units L, R. Both parts feed units L, R are in completely identical parts layout. This is intended to continue production by other parts feed unit R or L if parts are used up during production in one parts feed unit L or R. Fig. 3 (b) shows the motion of the parts feed units L, R in the event of parts shortage during production. In state (1), the parts feed unit L is in the process of production in the active position, while the parts feed unit R is located at the parts refill position not interfering the parts feed unit L. Herein, when parts shortage occurs, it is changed to state (2). That is, the parts feed unit L moves to the parts refill position, and the parts feed unit R moves to the active position to continue production. The operator refills the parts feed unit L. When further parts shortage occurs, the state becomes as shown in (3). That is, the parts feed unit R moves to the parts refill position, and the parts feed unit L moves to the active position to continue production. By thus exchanging the parts feed units L and R, drop of operation rate due to parts shortage is prevented. The conventional parts mounting method employing such plural parts feed units is specifically described below by referring to the flowchart in Fig. 4. Parts are sucked to the nozzles 2 from the parts feed unit L (step #101), and it is judged if there are parts or not (step #102), and if there are parts, parts are mounted on a board fixed on the X-Y table 3 (step #103). It is then checked if all parts to be mounted on the board by this mounting machine are completely mounted (hereinafter called EOP) or not (step #104), and the operation of steps #101 to #103 is repeated until reaching the EOP. When reaching the EOP, the mounted board is discharged, and next board is sent in (step #105). On the other hand, if shortage of parts is detected at step #102, the parts feed unit L is moved to the refill position (step #106), and production is continued by the parts feed unit R (steps #107 to #111). Herein, steps #107 to #111 are same in processing as steps #101 to #105. In the midst of steps #107 to #111, if parts shortage occurs at step #108, the parts feed unit R is moved to the refill position (step #112), and it is judged if the parts feed unit L running short of parts in the first place is still in the process of parts refill or not (step #113), and if it is in the process of parts refill, production is stopped due to parts shortage (step #121), or if parts refill has been complete, going back to step #101, production is continued in the parts feed unit L. In such mounting method, however, unless parts are refilled immediately by the operator, both the parts feed units L and R may be out of parts, and production may be stopped, so that the operation rate may decline. In particular, in the nighttime when the number of workers is small, it was difficult to operate continuously for a long time. In the light of the problems of the prior art, it is hence an object of the invention to present a parts mounting method capable of decreasing productions stops due to parts shortage, operating continuously for a long time, and enhancing the operation rate of the mounting machine. This is achieved by the features of claim 1 for a method for mounting parts by a parts mounting machine. Further embodiments are subject-matter of dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flowchart of a parts mounting method in an embodiment of the invention. Fig. 2 is a perspective view showing a schematic constitution of an electronic parts mounting machine. Fig. 3 is an operation explanatory diagram in the event of parts shortage at a parts feed unit in the same electronic parts mounting machine. Fig. 4 is a flowchart of parts mounting method in a prior art. BEST MODE OF CARRYING OUT THE INVENTION According to the parts mounting method of the invention, in the event of parts shortage, all of plural parts feed units are judged if the same parts are running short, if the same parts are not running out in any parts feed unit, the parts are supplied from such parts feed unit to mount parts, so that the production is not stopped if the production efficiency is lowered somewhat for exchanging the parts feed units, and the parts can be mounted continuously, so that the operation rate of the parts mounting machine may be enhanced. An embodiment of parts mounting method of the invention is described while referring to Fig. 1. The constitution of the parts mounting machine is same as the one shown in Fig. 2 relating to the prior art, and its description is omitted. The parts mounting method is explained by referring to the flowchart in Fig. 1. Parts are sucked to the nozzles 2 from the parts feed unit L (step #1), and it is judged if there are parts or not (step #2), and if there are parts, parts are mounted on a board fixed on the X-Y table 3 (step #3). It is then checked if all parts to be mounted on the board by this mounting machine are completely mounted (hereinafter called EOP) or not (step #4), and the operation of steps #1 to #3 is repeated until reaching the EOP. When reaching the EOP, the mounted board is discharged, and next board is sent in (step #5). If running out of parts at step #2, the parts feed unit L is moved to the refill position (step #6), and production is continued by the parts feed unit R (steps #7 to #11). Herein, steps #7 to #11 are same in processing as steps #1 to #5. In the midst of steps #7 to #11, if parts shortage occurs at step #8, the parts feed unit R is moved to the refill position (step #12), and it is judged if the parts feed unit L running short of parts in the first place is still in the process of parts refill or not (step #13). If parts refill has been complete, going back to step #1, production is continued in the parts feed unit L (steps #1 to #5). On the other hand, by the judgement at step #13, if parts refilling is not complete yet in the parts feed unit L first running out of parts, it is judged if the parts running out in the parts feed unit L and the parts running out in the parts feed unit R are same or not (step #14), and if same, the parts cannot be mounted, and the production is stopped due to parts shortage (step #21). By contrast, if judged to be different parts at step #14, parts are selectively sucked from both parts feed units L and R (step #15). For example, in Fig. 3, if parts A are used up in the parts feed unit L and parts B are used up in the parts feed unit R, as far as there are parts B and parts A respectively in the parts feed units L and R, parts necessary for production are present in the parts feed units, and it is not necessary to stop production, and therefore the parts B are sucked from the parts feed unit L and the part A, C to N from the parts feed unit R. Next, judging if the parts are present or running out (step #16), and if running out of parts, same as in step #14, it is judged if there are corresponding parts in the other parts feed unit (step #20), and if there are parts, going back to step #15, production is continued, and if parts are not available, shifting to step #21, production is stopped due to parts shortage. Or, if there are parts by the judgement at step #16, parts are mounted on the board fixed on the X-Y table 3 (step #17), and it is judged if all parts to be mounted on the board by this mounting machine are mounted (hereinafter called EOP) or not (step #18), and the operation of steps #15 to #17 is repeated until reaching the EOP. When reaching the EOP, the mounted board is discharged, and a next board is sent in (step #19). Thus, according to the embodiment, even in the case where production is stopped due to parts shortage in the prior art, production can be continued without stopping. INDUSTRIAL APPLICABILITY Thus, according to the parts mounting method of the invention, in the event of parts shortage, all of plural parts feed units are judged if the same parts are running short, if the same parts are not running out in any parts feed unit, the parts are supplied from such parts feed unit to mount parts, so that the production is not stopped if the production efficiency is lowered somewhat for exchanging the parts feed units, and the parts can be mounted continuously, so that the operation rate of the parts mounting machine may be enhanced.

Claims: Method for mounting parts by a mounting machine, said mounting machine comprising a plurality of interchangeable parts feed units (R, L), each parts feed unit (R, L) comprising a plurality of cassettes each containing a different type of parts (A, B, ... N), the method comprising the steps of: in a first operation, mounting (step #3, #9) parts (A, B,... N) from a parts feed unit (R, L) comprising all parts (A, B,... N) to be mounted; in a second operation, when in each of said plural parts feed units (R, L) at least one type of parts (A, B, ... N) to be mounted is in shortage, in the event when a shortage of a certain part (B) occurs of parts (A, B,... N) mounted from a first parts feed unit (R) of said plural parts feed units (R, L), judging (steps #14, #20) whether said certain part (B) is in shortage in each of said plural parts feed units (R, L), and when a result of said judging step (step #14, #20) is that of a non-shortage of said certain part (B) in a second parts feed unit (L) of said plural parts feed units (R, L), mounting (step #17) parts (A, B,...N) after supplying (step #15) parts (A, B,... N) selectively from both said first (R) and second (L) parts feed units. The parts mounting method of claim 1, wherein said first parts feed unit (R) is set to a refill position while mounting the parts (A, B, ... N) from said second parts feed unit (L), and said second parts feed unit (L) is set to a refill position while mounting the parts (A, B, ... N) from said first parts feed unit (R).

Inventors: NAGAE KAZUO, NAGAE, KAZUO
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1996
Main classification: H05K13
IPC codes: H05K13