WO2012074119A1

WO2012074119A1 - Automatic pouring method and apparatus

Info

Publication number: WO2012074119A1
Application number: PCT/JP2011/077999
Authority: WO
Inventors: Kouichi Banno; Tadashi Nishida
Original assignee: Sintokogio, Ltd.; Fujiwa Denki Co., Ltd.
Priority date: 2010-12-02
Filing date: 2011-11-28
Publication date: 2012-06-07
Also published as: JP5675027B2; JP2013544188A

Abstract

An automatic pouring method for pouring molten metal into a mold by controlling a pouring flow rate, includes: determining a pouring pattern based on a pouring amount, a pouring time, and a parameter; the pouring pattern representing a change in the pouring flow rate with an elapsed time and including a first point being a starting point of a pouring, a second point being a singular point of a gradient, a third point being a singular point of a gradient, a fourth point being a singular point of a gradient and a fifth point being an ending point of the pouring in sequence, and the parameter employing a pouring amount from a second point to a fourth point as a numerator, and a value obtained by integrating a pouring flow rate from a third point to the fourth point and a time from the second point to the fourth point as a denominator when pouring is started at a first point, an operation of stopping the pouring is started at the fourth point through the second point and the third point, the pouring is ended at a fifth point, and the pouring flow rate remains constant from the third point to the fourth point; and pouring molten metal into a mold based on the determined pouring pattern.

Description

DESCRIPTION

Title of Invention

AUTOMATIC POURING METHOD AND APPARATUS

Technical Field

[0001] The present invention relates to an automatic pouring method and an automatic pouring apparatus for pouring molten metal into a mold.

Background Art

[0002] A fixed program system or a teaching playback system has been conventionally employed to store a pouring operation of a pouring apparatus in foundries, and thereby perform automatic pouring.

[0003] In automatic pouring apparatuses on green sand casting lines, a method of teaching a pouring operation into a mold in advance and playing back the pouring operation is often employed. The teaching playback system in the automatic pouring apparatuses on the green sand casting lines is a method in which a pouring pattern (a ladle tilting speed per minute time, a flow rate per minute time and the like) by a skilled operator or a pouring pattern suited to a mold or a gating design of receiving molten metal based on a design or the like is preliminarily registered, and the registered pouring pattern is played back. Changes in tilting angle and flow rate different in each ladle, that is, ladle shape data are preliminarily stored as data. First, molten metal is poured by varying the ladle tilting speed at the center of a nozzle tip such that an optimum line of pouring flow is obtained while visually checking a line of pouring flow into a mold. For example, as shown in Figure 1, molten metal is poured by operating a variable knob 2 or the like provided on an operation panel 1. A display 3 is also provided on the operation panel 1. When an optimum pouring result is obtained, the pouring pattern is stored as casting data using a register button by assuming that an optimum casting speed program is obtained. The above operation is called teaching. The variable knob 2 is connected to a processor of a control device, and thereby connected to a tilting driving system.

[0004] A pouring operation into the same type of mold is achieved by the optimum casting program obtained by the teaching. That is, molten metal is poured with the flow rate from a start of pouring being sequentially converted into the ladle tilting speed from an actual pouring start position. The position (the height and the front-back position) of a pouring port obtained when the ladle is tilted differs depending on the shape or the size of the ladle. The height and the front-back position are moved such that the pouring port is at a constant position regardless of the ladle in use. The movement is performed at the same time as the tilting operation. The above operation is called playback. A teaching area is between the start of pouring and a stop of pouring (see Figure 2).

[0005] Figure 2 shows one example of a pouring pattern in the conventional teaching system. A vertical axis V represents a tilting angular speed (corresponding to a pouring flow rate), and a horizontal axis t represents an elapsed time. Reference character VI 02 denotes a pre-pouring tilting angular speed. Reference character T101 denotes a pre-pouring acceleration time after a start of pouring indicated by PI 00. Reference character T102 denotes a post-pouring deceleration time.

Reference character T103 denotes a teaching area. The start of pouring is detected at a point of P101 by an unillustrated pouring detector such as an optical sensor. Pouring is stopped at PI 02 where a required pouring amount is obtained based on a change in molten metal weight by a load cell.

Citation List

Patent Literature

[0006]

[Patent Literature 1] Japanese Patent No. 2668487

[Patent Literature 2] Japanese Patent No. 3361369

Summary of Invention

Technical Problem

[0007] However, the above teaching playback has a problem that data needs to be registered by actually pouring molten metal into a mold, and thus, a skilled operator having experience and intuition may be required. There is also a problem that the teaching is difficult to perform on a pouring pattern having a short pouring time of only a few seconds, and thus, molten metal may be insufficiently or excessively poured into a mold.

[0008] Thus, an automatic pouring method and an automatic pouring apparatus which allows molten metal to be poured into a mold on various molding lines at high speed without excess or deficiency by creating a pouring pattern that is simple and can be presented as numerical values is desired in the technical field.

Solution to Problem

[0009] An automatic pouring method according to one aspect of the present invention is an automatic pouring method for pouring molten metal into a mold by controlling a pouring flow rate, including: determining a pouring pattern based on a pouring amount, a pouring time, and a parameter; and pouring molten metal into a mold based on the determined pouring pattern, wherein the pouring pattern represents a change in the pouring flow rate with an elapsed time and includes a first point being a starting point of a pouring, a second point being a singular point of a gradient, a third point being a singular point of a gradient, a fourth point being a singular point of a gradient and a fifth point being an ending point of the pouring in sequence, and the parameter employs a pouring amount from the second point to the fourth point as a numerator, and a value obtained by integrating a pouring flow rate from the third point to the fourth point and a time from the second point to the fourth point as a denominator when an operation of stopping the pouring is started at the fourth point and the pouring flow rate remains constant from the third point to the fourth point..

[0010] An automatic pouring apparatus according to another aspect of the present invention includes: pouring flow rate controlling units which controls a pouring flow rate when molten metal is poured into a mold; and pouring pattern determining units which determines a pouring pattern based on a pouring amount, a pouring time, and a parameter, wherein the pouring pattern represents a change in the pouring flow rate with an elapsed time and includes a first point being a starting point of a pouring, a second point being a singular point of a gradient, a third point being a singular point of a gradient, a fourth point being a singular point of a gradient and a fifth point being an ending point of the pouring in sequence, and the parameter employs a pouring amount from the second point to the fourth point as a numerator, and a value obtained by integrating a pouring flow rate from-the third point to the fourth point and a time from the second point to the fourth point as a denominator when an operation of stopping the pouring is started at the fourth point and the pouring flow rate remains constant from the third point to the fourth point, wherein the pouring flow rate controlling units controls the pouring flow rate based on the pouring pattern determined by the pouring pattern determining units.

Advantageous Effects of Invention

[0011] According to various aspects and embodiments of the present invention, the pouring pattern is determined based on the set parameter in addition to the pouring amount and the pouring time determined for each product, so that a user can intuitively grasp the figure (the shape) of the pouring pattern. Since the pouring pattern can be also presented as numerical values, the pouring pattern can be easily controlled, and molten metal can be poured into a mold on various molding lines at high speed without excess or deficiency. Moreover, pouring can be appropriately performed by easily determining the pouring pattern for a product on which teaching is difficult to perform due to a short pouring time.

Brief Description of Drawings

[0012]

[Figure 1] Figure 1 is a view illustrating one example of a control panel provided in a pouring apparatus.

[Figure 2] Figure 2 is a view illustrating one example of a pouring pattern in a teaching system. [Figure 3] Figure 3 is a view illustrating a pouring pattern determined by a parameter (an FB ratio) in an automatic pouring method according to an embodiment.

[Figure 4] Figures 4 are views illustrating examples of the pouring pattern determined by the automatic pouring method along with changes in the FB ratio: Figure 4(a) is a view illustrating a pouring pattern in a case in which the FB ratio 1 ; Figure 4(b) is a view illustrating a pouring pattern in a case in which the FB ratio=l; and Figure 4(c) is a view illustrating a pouring pattern in a case in which the FB ratio<l .

[Figure 5] Figure 5 is a front view of an automatic pouring apparatus used for carrying out the automatic pouring method.

[Figure 6] Figure 6 is a side view of the automatic pouring apparatus. [Figure 7] Figure 7 is a system configuration diagram of the automatic pouring apparatus.

[Figure 8] Figures 8 are views illustrating examples of a pouring pattern by the automatic pouring apparatus: Figure 8(a) corresponds to Figure 4(a); Figure 8(b) corresponds to Figure 4(b), and Figure 8(c) corresponds to Figure 4(c).

[Figure 9] Figure 9 is a schematic view of a handwritten pouring pattern.

Description of Embodiments

[0013] In the following, an automatic pouring method and an automatic pouring apparatus according to one embodiment will be described by reference to the drawings. In the automatic pouring method according to the embodiment, a pouring pattern is determined by a pouring amount, a pouring time, and a predetermined parameter (also referred to as "FB ratio" below) when molten metal is poured into a mold by controlling a pouring flow rate, and molten metal is poured into a mold based on the determined pouring pattern.

[0014] Here, the pouring pattern represents a change in the pouring flow rate with an elapsed time as shown in Figure 3. The pouring pattern is a pattern having a first point PI to a fifth point P5 and composed of a straight line that sequentially connects the points. Also, a starting point of the pouring is the first point PI. An operation of stopping the pouring is started at the fourth point P4 through the second point P2 and the third point P3. The ending point of the pouring is the fifth point P5. Each of the second point P2, the third point P3 and the fourth point P4 is a singular point of a gradient. In the present embodiment, "a singular point of a gradient" is a changing point of a slope. For example, the singular point may be a connection point between different functions, an inflection point and a stationary point. The pouring flow rate remains constant from the third point P3 to the fourth point P4.

[0015] Also, the FB ratio (the parameter) is expressed by employing a pouring amount from the second point P2 to the fourth point P4 as a numerator, and a value obtained by integrating the pouring flow rate from the third point P3 to the fourth point P4 and a time from the second point P2 to the fourth point P4 as a denominator.

[0016] In the following, the pouring pattern shown in Figure 3 will be more specifically described. In Figure 3 or the like, a horizontal axis represents an elapsed time, and a vertical axis represents a pouring flow rate. A pouring amount from the first point PI indicating the start of pouring to the second point P2 is S 1. A pouring flow rate at the second point P2 is Ql. A pouring flow rate from the third point P3 to the fourth point P4 through which the pouring flow rate remains constant is Q2. A pouring amount obtained when it is assumed that the pouring flow rate remains Q2 through a time T3 from the second point P2 to the fourth point P4 is S2. That is, S2 is a pouring amount obtained by integrating the time T3 and the pouring flow rate Q2. Also, the pouring flow rate is changed from Ql to Q2 from the second point P2 to the third point P3. A flow rate difference (here, a flow rate difference of an increasing amount) with a case in which it is assumed that the pouring flow rate remains Q2 between the second point P2 and the third point P3 is S3. A pouring amount from the fourth point P4 to the fifth point P5 indicating the end of pouring is S4. That is, the pouring amounts SI to S4 are also amounts indicated by areas shown in Figure 3. A time T5 from the third point P3 to the fourth point P4 is a time for reducing an amount of molten metal that inertially flows out after stopping the pouring. The time T5 is about 2 seconds. A total pouring amount of the pouring amount SI from the first point PI indicating the start of pouring to the second point P2, and the pouring amount S4 from the fourth point P4 to the fifth point P5 indicating the end of pouring is empirically almost equivalent to an average flow rate in 2 seconds.

[0017] The FB ratio as the parameter for determining the pouring pattern is expressed by a next expression (1). The FB ratio is represented as X in the expression. The expression (1) can be transformed to an expression (2). X=(S3+S2)/S2 (1)

S3=S2x(X-l) (2)

[0018] When a pouring weight per casting is SO, the relationship of an expression (3) is obtained. Since (S1+S4) is generally equivalent to the average flow rate in 2 seconds, the relationship of an expression (4) is obtained. An expression (5) is obtained by putting the expressions (3) and (4) together.

S0=S1+S2+S3+S4 (3)

(Sl+S4)=2xS0/T3 (4)

(S2+S3)=S0-2xS0/T3 (5)

[0019] A next expression (6) is obtained from the expression (5) and the above expression (1). A next expression (7) is also obtained from the expressions (1) and (6).

S2=(S0/X)x(l-2/T3) (6)

S3=S0x(l-2/T3)x(X-l)/X (7)

[0020] A flow rate function Q(t) from the second point P2 to the third point P3 is expressed as shown in an expression (8). Here, a and b are constant numbers, and t represents the elapsed time from the start of pouring. An expression (9) is obtained from the expression (8) on the conditions of the second point P2, and an expression (10) is obtained from the expression (8) on the conditions of the third point P3. An expression (11) is obtained from the expressions (9) and (10).

Q(t)=axt+b (8)

Ql=axT2+b (9)

Q2=ax(T2+T3-T5)+b (10)

Ql-Q2=-ax(T3-T5) (11) [0021] An expression (12) is obtained by transforming the expression (11). An expression (13) is obtained from the expressions (12) and (9). a=-(Ql-Q2)/(T3-T5) (12)

b=Ql+T2x(Ql-Q2)/(T3-T5) (13)

[0022] The relationship among S2, Q2 and T3 is as shown in an expression (14) as described above. Also, S3 can be expressed as shown in an expression (15). The expression (15) is transformed to obtain an expression (16). The expression (16) is further transformed by using the expression (14), to obtain an expression (17).

Q2=S2/T3 (14)

S3=(Ql-Q2)x(T3-T5)/2 (15)

Ql-Q2=2xS3/(T3-T5) (16)

Ql=2xS3/(T3-T5)+S2/T3 (17)

[0023] Since the time T5 is about 2 seconds, it is shown that the pouring pattern can be determined only by the FB ratio based on the above relational expressions when the pouring weight and the pouring time of a product are determined. In other words, it is also shown that a desired pouring pattern can be obtained only by setting the FB ratio, and a user can intuitively picture the figure (the shape) of the pouring pattern.

[0024] Next, the function of the FB ratio will be described by using Figures 4. Figure 4(a) is a schematic view of a case in which the FB ratio is larger than 1 , where the flow rate of molten metal in the first half of the pouring is larger than that in the second half. Figure 4(b) is a schematic view of a case in which the FB ratio is 1, where the flow rate of molten metal remains constant throughout the pouring. Figure 4(c) is a schematic view of a case in which the FB ratio is smaller than 1, where the flow rate of molten metal in the second half of the pouring is larger than that in the first half. As shown in Figures 4, the figure (the shape) of the pouring pattern can be changed by varying the FB ratio. That is, it is shown that the pouring pattern can be changed (the cases in which the flow rate in the first half is larger, the flow rate remains constant, and the flow rate in the second half is larger) according to the shape or the gating design of a product. The pouring pattern can be also changed by changing the value of the time T5. For example, the pouring pattern can be applied to a product with a relatively long pouring time by increasing the value of the time T5, that is, increasing the time from the third point P3 to the fourth point P4. More specifically, since the time T5 is set to 2 seconds as a standard value and can be also changed to adjust the time from the third point P3 to the fourth point P4, the pouring pattern can be applied to products with a short pouring time to a relatively long pouring time.

[0025] As described above, in the automatic pouring method according to the embodiment, the pouring pattern is determined based on the set parameter in addition to the pouring amount and the pouring time determined for each product, so that a user can intuitively grasp the figure (the shape) of the pouring pattern. Since the pouring pattern can be also presented as numerical values, the pouring pattern can be easily controlled, and molten metal can be poured into a mold on various molding lines at high speed without excess or deficiency. Furthermore, pouring can be appropriately performed by easily determining the pouring pattern for a product on which teaching is difficult to perform due to a short pouring time.

[0026] In other words, in the method, the pouring pattern is not set based on intuition but can be determined by numerical values as the parameter for changing the pouring pattern, and thus, the pouring pattern is easily controlled. Another feature is in that, as a method for easily determining the pouring pattern for the product on which teaching is difficult to perform due to a short pouring time, the parameter as the FB ratio indicating the ratio of the pouring flow rates in the first half and the second half is provided in addition to the pouring weight and the pouring time determined for each product. The FB ratio may be considered as a ratio indicating which of the first half and the second half the pouring flow rate is emphasized in.

[0027] Accordingly, various advantages described below are provided by the automatic pouring method. The pouring figure is easily grasped since the FB ratio is provided in addition to the pouring weight and the pouring time determined for each product to calculate (determine) the pouring pattern that determines the pouring flow rate per elapsed time in an automatic pouring apparatus. Furthermore, the pouring pattern can be determined by numerical values, and is thus easily controlled. Also, the pouring pattern can be easily determined for the product on which teaching is difficult to perform due to a short pouring time. In other words, the pouring pattern that is simple, presented as numerical values, and suited to a manner of receiving molten metal based on each design of a gate, a core or the like can be created by the method. Accordingly, the method allows molten metal to be poured into a mold on various molding lines at high speed without excess or deficiency. [0028] Next, an automatic pouring apparatus 20 which carries out the automatic pouring method will be described. The automatic pouring apparatus 20 includes pouring flow rate controlling units 21 which controls a pouring flow rate when molten metal is poured into a mold, and pouring pattern determining units 22 which determines a pouring pattern based on a pouring amount, a pouring time, and an FB ratio described above. The pouring flow rate controlling units 21 controls the pouring flow rate based on the pouring pattern determined by the pouring pattern determining units 22.

[0029] More specifically, as shown in Figures 5 and 6, the automatic pouring apparatus 20 includes, on an upper surface of a carriage 30, a tilting driving device 32 which tilts a ladle 31, a vertical driving device 33 which vertically moves the tilting driving device 32, a front-back driving device 35 which moves the tilting driving device 32 and the vertical driving device 33 to and from a mold 34 made by an unillustrated molding machine, a load cell 36 which measures a total weight of the devices, a running driving device 37 which drives the carriage 30, a control device 38 which controls the devices, and an operation panel 39 which operates the automatic pouring apparatus.

[0030] As shown in Figure 7, the system configuration is roughly divided into a driving measurement system 25, the control device 38, a processor 27 in the control device 38, and the operation panel 39. The driving measurement system 25 includes a vertical shaft servo motor 40 of the vertical driving device 33, a front-back shaft servo motor 41 of the front-back driving device 35, a tilting shaft servo motor 42 of the tilting driving device 32, a running shaft servo motor 43 of the running driving device 37, and the load cell 36.

[0031] The control device 38 includes a vertical shaft servo amplifier 50 which drives the vertical shaft servo motor 40, a front-back shaft servo amplifier 51 which drives the front-back shaft servo motor 41 in the front-back direction, a tilting shaft servo amplifier 52 which drives the tilting shaft servo motor 42, a running shaft servo amplifier 53 which drives the running shaft servo motor 43, and the processor 27. A power source 26 is connected to the vertical shaft servo amplifier 50, the front-back shaft servo amplifier 51, the tilting shaft servo amplifier 52, and the running shaft servo amplifier 53.

[0032] The processor 27 includes a high-speed counter unit 60, an A/D conversion unit 61, a D/A conversion unit 62, and a central processing unit 63. The central processing unit 63 is connected to the operation panel 39. A display, various operation buttons and the like are provided on the operation panel 39 in a similar manner to Figure 1.

The central processing unit 63 works as the pouring flow rate controlling units 21 and the pouring pattern determining units 22 described above.

[0033] The central processing unit 63 outputs a speed instruction to the respective shaft servo amplifiers via the D/A conversion unit 62. The respective shaft servo motors are thereby driven, to respectively move a vertical shaft, a front-back shaft and a tilting shaft. Signals output from position detectors of the respective shaft servo motors are input into the high-speed counter unit 60 via the servo amplifiers. The central processing unit 63 can thereby obtain positional data. A speed/positioning unit can be thereby configured. A signal from the load cell 36 is also input via a load cell converter 54. The weight of molten metal can be thereby measured, and the pouring flow rate can be also calculated. A time from the start of pouring, and a pouring flow rate curve can be determined from the pouring pattern based on the FB ratio. Accordingly, a predetermined pouring pattern can be played back by feeding the molten metal flow rate back to the speed/positioning control on the respective shafts (see Patent Literatures 1 and 2). Figures 8 show actual pouring flow rate data obtained by pouring molten metal in the pouring patterns shown in Figures 4. Figures 8(a) to 8(c) respectively correspond to Figures 4(a) to 4(c).

[0034] A handwritten curve C12 as shown in Figure 9 may be also input or corrected on a touch panel of the display of the operation panel 39. For example, the curve may be input or corrected based on factors such as the size of a cavity or a gate, and the gas generation degree of a core. Automatic correction of the pouring pattern based on the pouring weight and the pouring time of a product may be also enabled. For example, the processor 27 works as adjusting units. The processor 27 increases the value of the time T5 as the pouring time of a product is longer. That is, the processor 27 increases the time T5 from the third point P3 to the fourth point P4 as the pouring time of the product is longer. With the configuration, the pouring pattern can be applied to a product with a relatively long pouring time. As described above, the time T5 is set to 2 seconds as the standard value, and can be also changed to adjust the time from the third point P3 to the fourth point P4 by the processor 27. Thus, the pouring pattern can be applied to products with a short pouring time to a relatively long pouring time. In Figure 9, reference character Cl l denotes a handwritten curve after being corrected, PI 1 a start of pouring, and P12 a stop of pouring.

[0035] The automatic pouring apparatus 20 according to the embodiment includes the pouring flow rate controlling units 21 and the pouring pattern determining units 22 as described above, and determines the pouring pattern based on the set parameter in addition to the pouring amount and the pouring time determined for each product. Therefore, a user can intuitively grasp the figure (the shape) of the pouring pattern. Since the pouring pattern can be also presented as numerical values, the pouring pattern can be easily controlled, and molten metal can be poured into a mold on various molding lines at high speed without excess or deficiency. Moreover, pouring can be appropriately performed by easily determining the pouring pattern for a product on which teaching is difficult to perform due to a short pouring time.

Reference Signs List

[0036]

20: Automatic pouring apparatus, 21 : Pouring flow rate controlling units, 22: Pouring pattern determining units, 31 : Ladle, 32: Tilting driving device, 33: Vertical driving device, 34: Mold, 38: Control device, 39: Operation panel, 63 : Central processing unit

Claims

[Claim 1]

An automatic pouring method for pouring molten metal into a mold by controlling a pouring flow rate, comprising:

determining a pouring pattern based on a pouring amount, a pouring time, and a parameter; and

pouring molten metal into a mold based on the determined pouring pattern,

wherein the pouring pattern represents a change in the pouring flow rate with an elapsed time and includes a first point being a starting point of a pouring, a second point being a singular point of a gradient, a third point being a singular point of a gradient, a fourth point being a singular point of a gradient and a fifth point being an ending point of the pouring in sequence, and

the parameter employs a pouring amount from the second point to the fourth point as a numerator, and a value obtained by integrating a pouring flow rate from the third point to the fourth point and a time from the second point to the fourth point as a denominator when an operation of stopping the pouring is started at the fourth point and the pouring flow rate remains constant from the third point to the fourth point.

[Claim 2]

The automatic pouring method according to claim 1 ,

wherein the determined pouring pattern is adjusted by changing a time from the third point to the fourth point, and

molten metal is poured into a mold based on the adjusted pouring pattern.

[Claim 3]

The automatic pouring method according to claim 2,

wherein the determined pouring pattern is adjusted by changing the time from the third point to the fourth point to be longer as the pouring time is longer.

[Claim 4]

An automatic pouring apparatus for pouring molten metal into a mold, comprising:

pouring flow rate controlling units which controls a pouring flow rate when molten metal is poured into a mold; and

pouring pattern determining units which determines a pouring pattern based on a pouring amount, a pouring time, and a parameter, wherein the pouring pattern represents a change in the pouring flow rate with an elapsed time and includes a first point being a starting point of a pouring, a second point being a singular point of a gradient, a third point being a singular point of a gradient, a fourth point being a singular point of a gradient and a fifth point being an ending point of the pouring in sequence, and

the parameter employs a pouring amount from the second point to the fourth point as a numerator, and a value obtained by integrating a pouring flow rate from the third point to the fourth point and a time from the second point to the fourth point as a denominator when an operation of stopping the pouring is started at the fourth point and the pouring flow rate remains constant from the third point to the fourth point, wherein the pouring flow rate controlling units controls the pouring flow rate based on the pouring pattern determined by the pouring pattern determining units.

[Claim 5]

The automatic pouring apparatus according to claim 4, further comprising

adjusting units which adjusts the determined pouring pattern by changing a time from the third point to the fourth point,

wherein the pouring flow rate controlling units controls the pouring flow rate based on the adjusted pouring pattern.

[Claim 6]

The automatic pouring apparatus according to claim 5, wherein the adjusting units adjusts the determined pouring pattern by changing the time from the third point to the fourth point to be longer as the pouring time is longer.