JPH05108114A - Production line process starting control system - Google Patents

Abstract

PURPOSE:To eliminate a product which becomes a waste over the time limit by judging whether or not the process can be stated under the conditions in which the working ate is the maximum without exceeding the time limit between processes for the product at a buffer. CONSTITUTION:A product is made to flow one by one, and the product is produced by using the facility at the production line composed. of a series of plural processes i, i+1,... Between a process; (i) of a processing time t during the production line and a p: i+1 of a subsequent processing time 5i+1, a time limit tau (when exceeding the product becomes a waste.) exists. In this case, for the product at a buffer (the place where the product for which the process cannot be started is temporarily put) before the process (i), without exceeding the time limit tau under the conditions to start the process (i) so that the facility working rate can be the maximum, and it is judged whether or not the process (i) can be started. For example, when the number of the servers (the number in which the processing can be performed in parallel) of the process (i) and the number ai of the products during the processing at the present time are made coincident, the process (i) is not started until ainot equal to si is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a production line, and more particularly to a production line process start control system for efficiently flowing a product when there is a time limit between processes.

[0002]

2. Description of the Related Art Conventionally, for example, when there is a time limit between the process i and the process i + 1, whether or not the process i can be started is determined by a worker on site.

[0003]

Since it is up to the operator to judge the process start in the above-mentioned conventional process start method, some products may be discarded in excess of the time limit due to too much product being accumulated in the buffer. On the contrary, there is a drawback that the product is not efficiently flowed due to the space between the products.

An object of the present invention is the time during which a product is discarded if this time limit is exceeded between a process i having a processing time t _{i in} a production line and a process i + 1 having a subsequent processing time t _{i + 1.} If there is a limit τ, the product in the buffer before the process i does not exceed the time limit τ between the process i and the process i + 1, and the operation rate of the process i is maximized.
By deciding whether it is possible to undertake the process i under the condition that the process is started, the above drawbacks are eliminated, and there are no products that are discarded beyond the time limit. It is an object of the present invention to provide a production line process start control system that can efficiently flow products, reduce the waste rate, shorten the production lead time, and improve the productivity.

[0005]

The production line process start control system of the present invention starts a production line process in which the products are flowed one by one and the products are produced using equipment in a production line consisting of a series of a plurality of processes. In the control method, when there is a time limit τ at which the product is discarded when the time limit is exceeded between the process i of a certain processing time t _i and the subsequent process _{i + 1} of the processing time t _{i + 1} in the production line. , The product in the buffer before step i has a time limit τ between step i and step i + 1
It is determined whether or not it is possible to start the process i under the condition that the process i is started so that the operating rate of the equipment of the process i is maximized without exceeding.

[0006]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a diagram showing the definition in the process of one embodiment of the present invention.

In FIG. 1, it is assumed that the production line is composed of a series of a plurality of processes, and the product is flowing through the line one by one.

It is assumed that a certain process in the production line is defined as a process i, a process subsequent to the process is defined as a process i + 1, and a buffer is provided between the processes. A buffer is a temporary storage area for products that cannot be processed. Further, the processing time of the process i and the process i + 1 are t
_i , t _{i + 1} , τ is the time limit from the end of the process i to the start of the process i + 1 (the product is discarded if the time limit is exceeded), and the number of servers of the process i and the process i + 1 is S Let _i and S _{i + 1} . The number of servers is the number of processes that can be performed in parallel (corresponding to the number of service windows in queuing theory), and represents, for example, the number of facilities and the number of workers. Further, the number of products being processed at the current time of the process i, the buffer between the process i and the process i + 1, the process i + 1, and the process i to the process i + 1 is a _i , a τ, respectively.
It is defined as a _{i + 1} , a. The processing time, the time limit, and the number of servers are default values, but the "number of products being processed at the current time" is a value that changes from moment to moment.

2 to 9 show a process start control system, FIGS. 2 and 3 are flowcharts of the process start control system, and FIGS. 4 to 9 are concrete examples of respective parts of the flow of the process start control system. Is represented.

FIG. 2 is a flow chart of a process start control system according to one embodiment of the present invention, FIG. 3 is a flow chart showing the details of step 6 of FIG. 2, and FIGS. 4 and 5 are specific examples of step 4 of FIG. FIGS. 6, 6 and 7 are diagrams showing a concrete example of step 5 in FIG. 2, FIG. 8 is a diagram showing a concrete example of FIG. 3, and FIG. 9 is FIG.
It is a figure which shows the other specific example of.

Here, in the flow of the process start control system of FIGS. 2 and 3, when looping under the condition surrounded by the double frame,
Indicates that you must wait until that condition is met.

In step 1 of FIG. 2, X is a coefficient representing a multiple of the processing time of the process i + 1, and X = 1 is given as its initial value.

In step 2 of FIG. 2, it is indicated whether or not the number of servers in the process i and the number of products being processed at the current time match. If they match, step i cannot be undertaken and one must wait until a _i ≠ S _i .

A concrete example of the case of "Yes" in step 3 of FIG. 2 is shown in FIGS. If the condition represented by step 4 in FIG. 2 is satisfied, the process i can be started, but if it is not satisfied, it is necessary to wait until this condition is satisfied. Step 3 of FIG.
6 and 7 show specific examples in the case of "No". If the condition represented by step 5 in FIG. 2 is satisfied, the process i can be started, but if it is not satisfied, the process proceeds to step 6 in FIG. 2 (details in FIG. 3).

FIG. 3 shows a process start control method when the condition of step 5 of FIG. 2 is not satisfied. Then, a specific example of FIG. 3 is shown in FIGS. Here, FIG. 8 is an example in which the condition (7) of FIG. 9 is observed when X = 2, and FIG.
= 1, 2, 3, ..., N.

FIG. 9 specifically shows the flowchart of FIG.

FIG. 9A shows whether or not the Si + 1-th product has passed (ti + 1-.tau.) Since the start of the process i (condition), and this condition is satisfied. If not, wait until it is satisfied and consider condition (2).

FIG. 9 (2) shows the condition 2 after the condition of (1) is satisfied and the S _{i + 1-} th product starts the process i.
t _{i +1} has passed (condition),
If this condition is met, step i can be started, but if not, wait until it is met,
Consider the condition (3).

Similarly, in (3) of FIG. 9, after the condition of (2) is satisfied, (2t _{i + 1} −τ) has passed since the 2S _{i +} 1th product started the process i. (Condition), and if this condition is not met,
Wait until it is satisfied, and consider condition (4).

FIG. 9 (4) shows whether or not 3t _{i + 1 of} the 3S _{i + 1-} th product has started the process i after the condition (3) is satisfied (condition). If this condition is satisfied, the process i can be started, but if it is not satisfied, wait until it is satisfied,
Consider the condition (5).

Similarly, as in (5) and (6) of FIG. 9, the condition → increase X by 1 → the condition is repeated until the condition is satisfied. Then, as in (7), t _i +
will repeat until the state equation of τ ≦ Xt i _{+ 1} is satisfied, and if the condition is not satisfied at the time of (7), i.e., be filled equation _{t i + τ ≦ Xt i +} 1 If the conditions are not met, wait until they are met,
Initiate step i.

The above system is called a production line process start control system.

[0024]

As described above, according to the production line process start control method of the present invention, the process i having a certain processing time t _i and the subsequent process i having a processing time t _{i + 1 in} the production line.
If there is a time limit τ at which the product is discarded when the time limit is exceeded during +1, the product in the buffer before the process i does not exceed the time limit τ between the process i and the process i + 1. Under the condition that the process i is undertaken so that the operating rate of i is maximized, it is determined that the process i can be undertaken, so that the process is over time and discarded. There is an effect that the product disappears, the product can be efficiently flown, the disposal rate is reduced, the production lead time is shortened, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a definition in a process of one embodiment of the present invention.

FIG. 2 is a flowchart of a process start control system according to an embodiment of the present invention.

FIG. 3 is a flowchart showing details of step 6 in FIG.

FIG. 4 is a diagram showing a specific example of step 4 in FIG.

5 is a diagram showing a specific example of step 4 in FIG.

FIG. 6 is a diagram showing a specific example of step 5 in FIG.

FIG. 7 is a diagram showing a specific example of step 5 in FIG.

FIG. 8 is a diagram showing a specific example of FIG.

FIG. 9 is a diagram showing another specific example of FIG. 3;

[Explanation of symbols]

i, i + 1 process t _i , t _{i + 1} processing time τ time limit S _i , S _{i + 1} number of servers a _i , a τ, a _{i + 1} , a process i, process i and process i +
Buffer between 1, step i + 1, step i to step i + 1
Up to the current time, the number of products being processed X times the processing time of process i + 1

Claims (1)

[Claims] 1. In a production line process start control system in which a product is flowed one by one and the product is produced in a production line consisting of a series of plural processes, a certain processing time t in the production line is set. If _i is the product exceeds the time limit during step i + 1 step i and processing time following thereafter t _{i + 1} of that time limit τ of destruction and discarding the product in said step i previous buffer, Under the condition that the step i is undertaken so that the operation rate of the equipment in the step i is maximized without exceeding the time limit τ between the step i and the step i + 1, A production line process start control method characterized by determining whether it is possible to start i.