JPS62124861A - Sampling control method in production line - Google Patents

Abstract

PURPOSE:To determine the optimum sampling cycle time by making the arrival time of the next work to the respective input side of all processors equal or larger than the arrival time of the preceding work to the respective output side of the corresponding processor and making the arrival time of the next work and the preceding work equal. CONSTITUTION:If the processing cycle time of each processor differs for each type of a work, the arrival time to the input side of each processor from a sampling device and the arrival time to the output side are determined for each type of the work. The arrival time of the next work to the respective input side of all processors is made equal to larger than the arrival time of the preceding work to the respective output side of the corresponding processor. Therefore, all works can be sampled without delay in any processor of all lines. The arrival time of the next work and the preceding work is made equal in one or more processors, thus all works can be sampled without generating wasteful vacancy in any processor of all lines.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides for
An extraction control method for a production line in which multiple processing devices such as heating equipment, rolling mills, press machines, etc. are arranged in series, where the processing cycle time of each processing device differs depending on the type of workpiece (loft or size). Regarding.

[Prior Art] In a conventional rolling line for seamless pipes, for example, a heating furnace serving as an extraction device for rolled material is arranged as the most upstream process, and a piercing rolling mill (hereinafter referred to as piercer) and an elongation rolling mill (mandrel mill) are installed as the most upstream process. and a reduction rolling 4!1 (stretch reducer), or a piercer, an elongator, a plug mill, a reeling mill, and a sizing mill. A method for determining the optimum extraction cycle time of the heating furnace in the above-mentioned rolling line is disclosed in Japanese Patent Application Laid-Open No. 5180721 or Japanese Patent Application Laid-Open No. 59-8
It is described in Publication No. 0722.

[Problem to be solved by the invention] The problems with the above conventional method are as follows.

■The above conventional method assumes that the area affected by extraction control, for example, from the heating furnace to the sizing mill, is filled with rolled material from the same lot. This is a control method for extracting rolled material from a heating furnace in a manner that shortens the time. However, in the conventional method described above, if there are rolled materials with multiple lofts within the range affected by extraction control, and in the most extreme case of 10 lofts per piece, the longest processing of those rolled materials The heating furnace will be extracted in cycle time. In this case, the cycle time of the entire line is regulated until the rolled material is extracted from the heating furnace and passes through the final rolling mill.

■When there is a size change between lofts 1. It is not possible to rationally determine the heating furnace extraction time of the next loft leading material.

The present invention is useful when aiming at high-mix low-volume production, etc.
Even if the extraction cycle time of the most upstream extraction device is continuous for 10 pieces of workpieces, for example, the optimal extraction cycle time is determined, and there is no congestion in any processing device on the entire line. It also aims to make it possible to extract all lofts and all pieces of workpieces without wasting time such as idle time.

[Means for Solving the Problems] The present invention provides an extraction manufacturing line in which a plurality of processing devices are arranged downstream of an extraction device, and the workpieces extracted from the extraction device are sequentially processed by subsequent processing devices. In the control method, if the processing cycle time of each processing device is different for each type of workpiece, the arrival time from the extraction device to the input side of each processing device and the arrival time to the output side of each processing device are determined for each type of workpiece. In this case, the arrival time to the input side of all processing devices for the zero-order workpiece is equal to or greater than the arrival time to the exit side of each corresponding processing device for the previous workpiece, and ■ one or more processing Regarding the apparatus, the extraction cycle time of the extraction apparatus is determined so that the arrival time of the next workpiece is equal to the arrival time of the previous workpiece.

[Operation] According to the present invention, the arrival time of the next workpiece to the input side of each processing device is equal to or greater than the arrival time of the previous workpiece to the exit side of each corresponding processing device. This makes it possible to extract all workpieces without any congestion in any processing device on the entire line. In addition, regarding one or more processing devices, the arrival time of the next workpiece is made to be equal to the arrival time of the previous workpiece, so
It becomes possible to extract all workpieces without creating unnecessary space in any processing device on the entire line.

[Example] As shown in FIG. 3, an extraction control method for a heating furnace will be described using a seamless pipe rolling line as an example. However, the present invention is widely applicable to all assembly, processing lines, etc. In addition, in Fig. 3, 1 is a round billet, 2
3 is a heating furnace, 3 is a piercer, 14 is a mandrel mill, 5 is a reheating furnace, and 6 is a stretch reducer. Since the rolling line is a straight, continuous line, the cycle time between pieces is determined by the interval at which steel pieces are extracted from the heating furnace, which is the most upstream process, or the extraction cycle time. The cycle time of the furnace becomes the cycle time of the rolling line. However, each rolling mill has its own cycle time depending on its rolling loft and size, and there is a possibility that any one of them may become a cycle time bottleneck. In addition, if rolled materials of the same rolling size are flowing on the entire rolling line including the heating furnace, extraction control is not necessarily necessary, but if the size change is 10 or 1, there will be bottleneck equipment before and after the change. and typically have different specific cycle times.

For example, assume that the neck equipment for the previous size of rolled material is a stretch reducer and the cycle time is 17.0 seconds, and the neck equipment for the next size of rolled material is a piercer and the cycle time is 16.0 seconds. In this case, after the final material of the previous size is extracted from the heating furnace.

The first wood of the next size is extracted in 17.0 seconds, but the second grain is 1
Is it okay to extract it in 6.0 seconds? No. This is because even though the final material has been extracted from the previous size of rolled material, there are several pieces on the line before the stretch reducer, so the cycle time for the next size of rolled material is 16.
．． Pieces extracted in 0 seconds become jammed on the rolling line.

So, at what point will the cycle time of the next size be 16.0?
It will be possible to extract it in seconds, when the final material of the previous size passes through the stretch reducer, which is the neck equipment for the rolled material of the previous size. Therefore, some pieces of the next size will have a cycle time of 1 for the next size.
Unable to extract in 6.0 seconds, previous size cycle time 1
I am forced to extract it in 7.0 seconds.

Furthermore, when the rolling size is a small lot, that is, when there are three or more rolling sizes on the rolling line, how should the extraction cycle time be determined?

Let's go back to the basics and think about the principle of optimal cycle time. The heating furnace extraction cycle time is as follows: ■The current heating furnace extracted material must not reach the entrance side of the rolling mill before the previous heating furnace extracted material has finished rolling in the rolling mill.If it does, it will cause a "traffic jam."

■The material extracted from the heating furnace this time must reach the input side of the rolling mill immediately after the material extracted from the heating furnace last time completed rolling in the rolling mill. If it does not reach the rolling mill, it will be "wasted time."

In order to express the above situation in a unified manner, we created the model shown in Figure 2.

(b) The time it takes for the final material A to reach the inlet and outlet of each rolling mill after being extracted from the heating furnace is expressed by the following formula.

TPEA = ΔtRP TPXA = ΔtRP + τPA TMEA = ΔtRP + τPA + ΔtPMTMXA =
ΔtRP + τPA+ ΔtPM + 7 MATH
EA =ΔtRP+τPA+ΔtPl'l+τHA+Δ
tMHTHXA= ΔtRP + τPA+ ΔtPM
+ τHA + ΔtMH+ = HA After the leading material of lot B is out at the optimum extraction cycle time, the time required for it to reach the inlet and outlet of each rolling mill is expressed by the following formula in the same way as in A.

Ding PEB = 7 out + Δt RPT
PXB= τout + Δt RP+ τPBTME
B= τout + Δt RP+ τPB+ Δt
PHTMXB= τout +Δt RP+ τPB+
Δt PM+ τMBTHEB= τout +Δt
RP+ τPB+Δt PM+ τMB+ΔtM)I THXB= τout +ΔtRP+ τPB+ΔtP
M+? MB+ΔtM)I+τHB The boundary condition between Lot A and Lot B is that when the final material from Lot A passes through each rolling mill and reaches the exit side, the leading material from Lot B has reached the input side of each rolling mill. . Since there are cases where it is not reached, the boundary condition becomes the following equation if we include an inequality sign as a mathematical expression.

TPEB≧TPXA (1)T
NEB≧TNXA (2)TH
EB ≧ TH By doing so, it is possible to extract rolled material from any rolling mill on the entire line without any congestion. In addition, ■With regard to one or more rolling mills, the arrival time of lot B is made equal to the arrival time of lot A, so that rolled material can be extracted from any rolling mill on the entire line without creating unnecessary space. It is something to do.

By substituting the equations for the arrival times at each point of A lot and B lot into equations (1), (2), and (3), the following equation can be derived.

τout' ≧t PA (
4) τout”+?PB ≧?PA+τMA
(5) τout''+ τPB+ τMB≧?PA
＋? MA+ τHA (6) (4), (5) and (
By rearranging equation 6), equation (7) is obtained.

τPA −τout≧0τP
A −τPB+ τMA −τout≧0
τ PA −? PB+ τHA -1MB+ τ
HA−τ out ≧ 0 where Z= τout
As (8), it is recognized that the minimum value of Z may be determined from the minimum value of the three τout determined by equation (7).

It can be easily estimated that the equation (8) is not an equation that holds only between lofts, but also holds between pieces. Therefore, when applied to an actual rolling line, by solving the objective function Z for each piece, the optimum cycle time can be rationally determined even in the most severe case of 1 piece or 10 pieces.

Equation (7) is slightly modified to obtain equation (10).

τout'=τPA? out”= (τPA −c PB) + τMA
τout−= (?PA −?PB) + (τMA−
τMB)+ and HA (10)(
The maximum τout among the three τouts in equation 10) is the optimal extraction cycle time. The calculation formula is shown in equation (11).

c out = WAX (τout', τout''
, τout”) (11) The cycle time of the heating furnace is determined by thermal calculations and constraints such as uneven heat (skid marks) obtained in actual operation. Therefore, more preferably, equation (11) is used. Obtained extraction cycle time τou
t and the cycle time τR of the heating furnace are compared and the larger one is selected. As a result, for the first time, the optimum target extraction cycle time τAIM for the entire rolling line is determined by equation (12).

? AIM = WAX(τout, ?R)
(12) If there is a size change, the cycle time τM of the rolling mill for the final pre-loft material
A, τPA, τHA, their cycle times τP
τPA+KB, τMA+KB, τHA+ which is A, τMA, τHA plus B for the time required to change the size of the next lot
If we use KB and set up the inequalities of equations (1) to (7), we get
It is possible to handle it as a unified model without creating a special mathematical model.

The above is the heating furnace extraction control method. Even if the specific cycle time of each rolling mill is determined using the method described in JP-A-59-80721 and JP-A-59-80722,
It is possible to obtain the same effect as the method described here.

Hereinafter, the control procedure of the present invention will be explained based on FIG.

First, a manual input device such as a host computer 11 or a CRT for inputting information necessary for the operation and extraction control model, such as rolling instructions, loft, size, etc., into the extraction control computer 12 is arranged. The extraction control computer 12 is
Based on the input information, calculate the optimum extraction cycle time by calculating formulas (1) to (12) for all lofts and pieces, and set the extraction timer corresponding to each loft and piece. . An extraction command is output to the extractor control device 13 every time the extraction timer counts up.

The extractor control device 13 operates the steel piece extractor 14 to extract steel pieces 16 from the inside of the heating furnace 15 . Repeat this action.

Hereinafter, specific implementation results of the present invention will be explained.

Table 1 The effects of the present invention will be verified in the case where the unique cycle times of A lot or A piece and B lot or B piece are determined as shown in Table 1. Since the piercer is the bottleneck for A lot, B lot is extracted at the optimum extraction cycle time of A lot until the final material of A lot passes through the piercer.

However, if the final material of lot A passes through the piercer, lot B can be extracted with the own optimum cycle time of 15.2 seconds. Conventionally, after the A lot passes through the stretch reducer, the cycle time is switched to the B lot, and in other cases, the final material of the A lot is extracted at the optimum cycle time of the B lot as soon as it passes through the heating furnace. In the former case, if there are 50 pieces of material between the heating furnace and the stretch reducer, and 5 pieces of material between the heating furnace and the piercer, (
15.4 seconds - 15.2 seconds) X (50 pieces - 5 pieces) Productivity improves by 29 seconds. In the latter case, the materials would be jammed in front of the piercer, and in the end, extraction of B lot would be delayed (15, 2).
seconds - 15.4 seconds) x 5 pieces = 1.0 seconds, the temperature of the extracted material will drop, and the material in the furnace will overheat, resulting in wasted energy. .

[Effects of the Invention] As described above, the present invention provides an extraction manufacturing line in which a plurality of processing devices are arranged downstream of an extraction device, and the workpieces extracted from the extraction device are sequentially processed by the subsequent processing devices. In the control method, if the processing cycle time of each processing device is different for each type of workpiece, the arrival time from the extraction device to the input side of each processing device and the arrival time to the output side of each processing device are determined for each type of workpiece. ■The arrival time to the input side of all processing devices for the next workpiece is equal to or greater than the arrival time to the exit side of each corresponding processing device for the previous workpiece, and ■One or more processing Regarding the apparatus, the extraction cycle time of the extraction apparatus is determined so that the arrival time of the next workpiece is equal to the arrival time of the previous workpiece.

Therefore, for example, even when processing 10 to 1 piece of workpieces, it is possible to determine the optimal extraction cycle time for the most upstream extraction device, so that there is no congestion in any processing device on the entire line, and there is no empty space. No wasted time,
It becomes possible to extract processed products from all lots and all pieces.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a control procedure of the present invention, FIG. 2 is a diagram showing an extraction control model of the present invention, and FIG. 3 is a layout diagram showing a seamless pipe rolling line. 12...Extraction control computer, 13...Extractor control device, 14...Extractor, 15...Heating furnace, 16
...A piece of steel. Agent Patent Attorney Osamu Shiokawa Figure 1 Figure 2

Claims (1)

[Claims] (1) Place multiple processing devices downstream of the extraction device,
An extraction control method for a production line in which a workpiece extracted from an extraction device is sequentially processed by subsequent processing devices, and when the processing cycle time of each processing device is different for each type of workpiece, , the arrival time from the extraction device to the input side of each processing device and the arrival time to the output side are determined. Extraction is performed such that the arrival time of the next workpiece is equal to or greater than the arrival time of each device to the exit side, and [2] With respect to one or more processing devices, the arrival time of the next workpiece is equal to the arrival time of the previous workpiece. A production line extraction control method that determines the extraction cycle time of the equipment.