Molding system and molding method

Abstract

This technology provides a way to properly detect nozzle clogging. [Solution] The molding system for forming a sand mold comprises a mold, a tank connected to a compressed air source with an open end for storing sand, a nozzle attached to the end of the tank for guiding the sand in the tank into the mold, and a control unit that outputs information regarding nozzle clogging when the time from the start of sand filling to reaching a predetermined pressure is shorter than a pre-acquired initial pressure.

Description

Technical Field

[0001] The present disclosure relates to a modeling system and a modeling method.

Background Art

[0002] Patent Document 1 discloses a modeling device. This device includes a tank for storing sand inside and a nozzle for guiding the sand in the tank into a mold. Compressed air is supplied into the tank, and the sand in the tank is supplied into the mold through the nozzle by the pressure. The pressure in the tank is detected by a pressure sensor, and a graph showing the relationship between the pressure and time is displayed on a display. When the pressure detected by the sensor exceeds a preset threshold value, an operator determines that clogging of the nozzle has occurred.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the device described in Patent Document 1, since the occurrence of nozzle clogging is determined by an operator, there is room for improvement in order to more accurately detect the occurrence of nozzle clogging. The present disclosure provides a technique capable of appropriately detecting the occurrence of nozzle clogging.

Means for Solving the Problems

[0005] One aspect of this disclosure is a molding system for molding a sand mold. The molding system comprises a mold, a tank, a nozzle, and a control unit. The tank is connected to a compressed air source, has an open end, and stores sand inside. The nozzle is attached to the end of the tank and guides the sand in the tank into the mold. During sand filling, in which sand from the tank is introduced into the mold via the nozzle, the control unit outputs information regarding nozzle clogging when the time from the start of sand filling to reaching a predetermined pressure is shorter than a pre-acquired initial pressure. Nozzle clogging refers to a state in which sand is compressed in the sand filling nozzle that introduces sand into the mold, completely blocking the flow path and preventing sand filling, or a state in which part of the flow path is blocked, reducing the amount of sand filled.

[0006] If a nozzle becomes clogged, the pressure inside the tank increases. As a result, the time it takes to reach the predetermined pressure is shortened. In this molding system, when the time from the start of sand filling to reaching the predetermined pressure is shorter than the time to reach the predetermined pressure, information regarding nozzle clogging is output. In this way, nozzle clogging is detected mechanically, so this molding system can detect the occurrence of nozzle clogging more appropriately than when judged by an operator.

[0007] In one embodiment, the control unit may perform an operation to clear the nozzle blockage when the above-described relationship is satisfied. By configuring in this way, the molding system can avoid molding defects caused by insufficient sand filling due to nozzle blockage.

[0008] In one embodiment, the control unit may issue an alarm when the above-described relationship is satisfied. With this configuration, the molding system can notify the operator or others that a nozzle blockage has occurred.

[0009] In one embodiment, the molding system includes an analysis device that images the sand mold and performs a visual inspection of the sand mold based on the captured image, and the control unit may output information to the analysis device when the above-described relationship is satisfied. With this configuration, the molding system can perform image analysis of the molded sand mold when nozzle clogging occurs.

[0010] In one embodiment, the analysis device may further include an external force application device that applies pneumatic pressure to the sand mold before imaging the sand mold, once information has been acquired from the control unit. With this configuration, the molding system can remove sand that has fallen onto the surface of the sand mold by moving it with pneumatic pressure.

[0011] In one embodiment, the analysis device is configured to switch between a standard mode that images the sand mold at a first magnification and a high-magnification mode that images the sand mold at a magnification higher than the first magnification, and when information is acquired from the control unit, the sand mold may be imaged at least in high-magnification mode. With this configuration, the molding system can perform a more detailed image analysis of the sand mold formed when a nozzle clog occurs.

[0012] In one embodiment, the molding system includes a squeeze mechanism for squeezing the sand filled in the mold, a sand cutter for shaping the sand mold, and a pressure sensor for detecting the squeeze pressure. The control unit determines whether the squeezing by the squeeze mechanism has been completed successfully based on the detection result of the pressure sensor, and the sand cutter may change its operation depending on whether the nozzle is clogged and whether the squeezing has been completed successfully. The hardness (mold strength) of the sand mold may differ depending on whether the squeezing has been completed successfully or not. By changing the operation of the sand cutter in the molding system depending on whether the squeezing has been completed successfully, the collapse of the sand mold can be avoided.

[0013] In one embodiment, if the above-described relationship is not satisfied and the control unit determines that the squeeze has been completed successfully, the sand cutter may operate so that the relative speed between the sand mold and the blade is a first speed. If the above-described relationship is satisfied and the control unit determines that the squeeze has not been completed successfully, the sand cutter may operate so that the relative speed between the sand mold and the blade is a second speed, which is lower than the first speed. In this way, if there is a nozzle blockage and the squeeze has not been completed successfully, the sand cutter slows down the relative speed between the sand mold and the blade compared to when there is no nozzle blockage and the squeeze has been completed successfully. This allows the sand cutter to avoid collapsing the sand mold.

[0014] Another aspect of this disclosure is a molding method which includes the following steps: (1) A process of introducing sand from a tank connected to a compressed air source, with an open end and containing sand, into a casting frame via a nozzle attached to the end of the tank. (2) In the process of introducing sand into the casting frame, when the time from the start of sand filling to reaching a predetermined pressure is shorter than the initial time to reach the predetermined pressure, the process of outputting information regarding nozzle clogging. This molding method produces the same effect as the molding system described above. [Effects of the Invention]

[0015] The technology disclosed herein provides a method for appropriately detecting the occurrence of nozzle clogging. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows an example of the configuration of a casting system equipped with a molding system according to the embodiment. [Figure 2] Figure 1 is a block diagram of the molding system. [Figure 3] This is a longitudinal cross-sectional view showing the state of the 3D printer before the start of the 3D printing operation (in its original position). [Figure 4]It is a longitudinal sectional view showing the state of a molding machine that forms a molding space and fills sand in the space. [Figure 5] It is a longitudinal sectional view showing the state of the molding machine during squeezing. [Figure 6] It is a longitudinal sectional view showing the state of the molding machine returning to its original position after mold extraction. [Figure 7] It is a front view of the sand cutter. [Figure 8] It is a view taken in the direction of arrow VIII-VIII in FIG. 7. [Figure 9] It is a graph showing the initial pressure change of the sand tank and the pressure change at the time of detection target.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are not repeated. The dimensional ratios in the drawings do not necessarily match those in the description. The terms “upper”, “lower”, “left”, and “right” are based on the illustrated state and are for convenience.

[0018] [An Example of a Casting System] FIG. 1 is a diagram showing an example of the configuration of a casting system provided in a molding system according to an embodiment. The casting system 100 shown in FIG. 1 is a system for manufacturing castings. As shown in FIG. 1, the casting system 100 includes a molding machine 2, a conveying line 3, a sand cutter 4, an analysis device 5, and a line control unit 6 (an example of a control unit). The X direction and Y direction in the figure are horizontal directions, and the Z direction is the vertical direction. The X direction, Y direction, and Z direction are axial directions orthogonal to each other in a three-dimensional space orthogonal coordinate system.

[0019] The molding machine 2 is a device for manufacturing sand molds M. The molding machine 2 forms the sand mold M using a casting frame F. The molding machine 2 is connected to the line control unit 6 for communication. Upon receiving a molding start signal from the line control unit 6, the molding machine 2 starts manufacturing the sand mold M in the molding area. The molding machine 2 puts sand (foundry sand) into the casting frame F in which the model (pattern) is placed, and pressurizes and compacts the sand in the casting frame F. The molding machine 2 forms the sand mold M by removing the pattern from the compacted sand. The sand mold M is either an upper mold or a lower mold, which are composed of a pair.

[0020] The transport line 3 is equipment for transporting sand molds M from upstream to downstream. The transport line 3 receives the sand molds M from the molding machine 2 and transports them toward the pouring machine (not shown) downstream. The transport line 3 may include, for example, a roller conveyor, rails, a trolley on which the sand molds M and casting frames F are placed and which runs on the rails, a pusher device located on the molding machine 2 side, and a cushioning device located on the pouring machine side. If the transport line 3 has drive rollers, a roller running surface is provided on the base plate B. The transport line 3 sequentially transports a plurality of sand molds M and casting frames F arranged at equal intervals on the roller conveyor or rails from the molding machine 2. The transport line 3 operates intermittently, transporting the sand molds M and casting frames F in predetermined frame portions. The predetermined frame portion may be one frame or multiple frames. The transport line 3 is connected to the line control unit 6 in a communicative manner. The transport line 3 transports a predetermined number of sand molds M and casting frames F in response to receiving a frame feed signal from the line control unit 6. When the transport line 3 has completed transporting the predetermined number of frames, it transmits a frame feed completion signal to the line control unit 6.

[0021] The sand cutter 4 is installed on the conveying line 3 and adjusts the shape of the sand mold M. The sand cutter 4 adjusts the shape of the sand mold M by, for example, applying its blade to the sand mold M while it is being conveyed. The sand cutter 4 is communicatively connected to the line control unit 6. The sand cutter 4 operates based on the control signals of the line control unit 6. For example, the sand cutter 4 has a lifting mechanism that raises and lowers its blade to move closer to or further away from the sand mold M. Based on the control signals of the line control unit 6, the sand cutter 4 stops its blade at a height that contacts the excess sand of the sand mold M while it is being conveyed. As an example, the height of the blade is adjusted so that it contacts the excess sand formed on the back of the sand mold M. When the blade height adjustment is complete, the line control unit 6 conveys the continuous sand mold M one pitch (one frame) in the frame travel direction. As a result, when the sand mold M passes the position of the sand cutter 4, the excess sand in the sand mold M being transported is cut by the blade of the sand cutter 4, and the sand mold is flattened. The sand cutter 4 may also be configured to move its blade horizontally based on the control signal of the line control unit 6. For example, the sand cutter 4 may move its blade relative to the sand mold M while it is stopped or being transported to cut the excess sand in the sand mold M. The sand cutter 4 may also adjust the shape of the sand mold M by changing the relative speed between the sand mold M and the blade. Details of the sand cutter 4 will be described later.

[0022] The analysis device 5 is installed on the transport line 3 and images the sand mold M on the transport line 3, and performs a visual inspection of the sand mold based on the captured image. The analysis device 5 may be connected to the line control unit 6 for communication. The analysis device 5 and the line control unit 6 may operate in cooperation. Details of the analysis device 5 will be described later. After the analysis is complete, the sand mold M is transported to the core setting area W. Workers are stationed in the core setting area W and set cores in the sand mold M. The sand mold M with the cores set is transported by the transport line 3 to the area where the next process is performed.

[0023] The line control unit 6 is a controller that provides overall control of the casting system 100. The line control unit 6 is communicated with the molding machine 2, the transport line 3, the sand cutter 4, and the analysis device 5. The line control unit 6 works in cooperation with the molding machine 2, the transport line 3, the sand cutter 4, and the analysis device 5 to constitute the molding system 1. The molding system 1 does not necessarily have to include the sand cutter 4 and the analysis device 5.

[0024] [Details of the molding system] Figure 2 is a block diagram of the molding system shown in Figure 1. As shown in Figure 2, the molding system 1 comprises a molding machine 2, a sand cutter 4, an analysis device 5, and a line control unit 6.

[0025] The line control unit 6 is configured as a computer system including, for example, a processor 61 such as a CPU (Central Processing Unit), memory 62 such as RAM (Random Access Memory) and ROM (Read Only Memory), storage 63 such as an HDD (Hard Disk Drive), input units 64 such as a mouse and keyboard, and output units 65 such as a display. The line control unit 6 may also be configured as a PLC (Programmable Logic Controller). The line control unit 6 realizes its functions by operating each piece of hardware under the control of the processor based on a computer program stored in memory.

[0026] The molding machine 2 includes a molding control unit 20 and a sensor 21. The molding control unit 20, like the line control unit 6, includes a processor and memory. The molding control unit 20 controls the operation of the molding machine 2 based on instructions from the line control unit 6. The molding machine 2 manufactures a sand mold M based on mold information received from the line control unit 6 by the molding control unit 20. The mold information includes information indicating the type of product model. The sensor 21 acquires various data during the manufacturing process of the molding machine 2. The sensor 21 includes a pressure sensor PA that detects the pressure in the sand tank of the molding machine 2, which will be described later. The sensor 21 may also include a pressure sensor PB that detects the squeeze pressure of the molding machine 2, which will be described later. The molding control unit 20 outputs the results detected by the sensor 21 to the line control unit 6.

[0027] The analysis device 5 comprises an analysis control unit 50, an imaging device 51, and an external force application device 52. The analysis control unit 50, like the line control unit 6, includes a processor and memory. The analysis control unit 50 controls the operation of the imaging device 51 and the external force application device 52 based on instructions from the line control unit 6. Based on the mold information received from the line control unit 6, the analysis control unit 50 identifies the type of sand mold M to be inspected and inspects the sand mold M according to the type of sand mold M.

[0028] The imaging device 51 images the sand mold M on the transport line 3. The imaging device 51 includes a variable magnification lens and an image sensor. The imaging device 51 images the sand mold M in either standard mode or high magnification mode and outputs the image. Standard mode is a mode in which the sand mold M is imaged at a first magnification, and high magnification mode is a mode in which the sand mold M is imaged at a magnification higher than the first magnification.

[0029] The analysis control unit 50 outputs a signal indicating whether the sand casting mold M to be inspected is normal or not, based on the type of sand casting mold M and the image of the surface of the sand casting mold M that has been captured (inspection image). For example, the analysis control unit 50 uses an image of the surface of a normal sand casting mold M as a reference image, and stores the image obtained by the imaging device 51 capturing a normal sand casting mold M in a memory device or similar for each sand casting mold M. The analysis control unit 50 outputs a signal indicating the inspection result in the following sequence, for example. First, the analysis control unit 50 matches the color tones of the inspection image and the reference image. Next, the analysis control unit 50 generates a difference image between the inspection image and the reference image. Next, the analysis control unit 50 removes noise from the difference image. Next, the analysis control unit 50 performs particle analysis on the difference image and calculates feature quantities such as the position, area, and length of blobs in the difference image. The analysis control unit 50 determines whether each blob is a defect or not based on the minimum defect size, and detects the remaining blobs as defects by removing the blobs that have been determined not to be defects from the difference image. Next, the analysis control unit 50 identifies pseudodefects from the clumps (defects) included in the difference image, for example, based on the color of the clumps (defects). A pseudodefect is, for example, a part of the surface of the object where the brightness is increased due to light reflection, and is not actually a defect. The analysis control unit 50 removes the pseudodefects from the difference image and generates a defect image. If the defect image does not contain any defects, the analysis control unit 50 outputs a signal indicating that the sand mold M to be inspected is normal. If the defect image contains defects, the analysis control unit 50 outputs a signal indicating that the sand mold M to be inspected is abnormal.

[0030] The external force application device 52 applies air pressure to the sand mold M. For example, before imaging the sand mold M, the external force application device 52 applies an airflow rate (800 L / min) sufficient to move the sand. This allows the external force application device 52 to move the sand adhering to the surface of the sand mold M, exposing the surface of the object to be inspected. The external force application device 52 is, as an example, a blower equipped with a fan or a blower.

[0031] [Details of the 3D printer] Figure 3 is a longitudinal cross-sectional view showing the state of the molding machine before the start of the molding operation (in its original position). Figure 4 is a longitudinal cross-sectional view showing the state of the molding machine after the molding space has been formed and filled with sand. Figure 5 is a longitudinal cross-sectional view showing the state of the molding machine during the squeeze operation. Figure 6 is a longitudinal cross-sectional view showing the state of the molding machine returning to its original position after demolding. Figures 3 to 6 show the states of molding machine 2 at "original position," "sand filling," "squeezing," and "returning to original position."

[0032] As shown in Figures 3 to 6, the molding machine 2 is equipped with a sand tank 22 (an example of a tank). The sand tank 22 stores sand 23 inside. The sand tank 22 is connected to a compressed air source (not shown) and has a filter 22a on its inner surface with an air outlet for blowing out air. The lower end of the sand tank 22 is open. A nozzle 24 is provided at the lower end of the sand tank 22.

[0033] A casting frame F is positioned below the sand tank 22. The casting frame F, together with at least a pattern plate 25, forms a molding space 26 (see Figure 4). The sand 23 stored in the sand tank 22 is guided into the molding space 26 (an example within the casting frame F) by a nozzle 24.

[0034] A segmented squeeze foot 27 (an example of a squeeze mechanism) is provided at the lower end of the sand tank 22, adjacent to the nozzle 24. The squeeze foot 27 functions as a squeeze means to compress the sand 23 filled in the molding space 26.

[0035] Furthermore, the molding machine 2 is equipped with a molding base 28. Multiple frame set cylinders 29 are erected on this molding base 28. A lifting support frame 30 is also installed between the tips of the piston rods 29a of the frame set cylinders 29. That is, the frame set cylinders 29 are erected with the molding base 28 side facing upwards as the retracted end. As shown in Figure 6, the frame set cylinders 29 are equipped with pressure sensors PB for detecting squeeze pressure.

[0036] Below one of the multiple frame set cylinders 29, the central part of the pattern changing device 31 is supported so as to be rotatable in a horizontal plane. At both ends of this pattern changing device 31, pattern carriers 32 on which the aforementioned model plates 25 are placed are set, lifted by approximately 5 mm by springs (not shown), and configured to alternately move the model plates 25 in and out of the upper center of the molding base 28.

[0037] The aforementioned sand tank 22 is suspended from the lifting support frame 30. A sand inlet 22b, which is opened and closed by a slide gate 33, is provided at the upper end of the sand tank 22. As described above, an air ejection filter 22a is provided on almost the entire inner surface of the sand tank 22. The filter 22a is a porous material with numerous holes of about 10 μm to 80 μm provided on its entire surface, and is made of, for example, sintered ultra-high molecular weight polyethylene. A hollow chamber 22c is formed between the filter 22a and the inner surface of the sand tank 22. Compressed air of 0.05 MPa to 0.18 MPa is supplied to the hollow chamber 22c from a compressed air source (not shown) that is connected via an upper air passage 34 and a lower air passage 35. A pressure sensor PA for detecting the pressure inside the sand tank 22 is also provided in the hollow chamber 22c. In the sand tank 22 configured in this way, compressed air is ejected from multiple holes in the filter 22a to cause the sand 23 to become suspended and fluid, and the sand 23 is filled into the molding space 26 while it is suspended and fluid.

[0038] The squeeze foot 27 and nozzle 24 described above, together with the model plate 25, casting frame F, and molding frame 36, form the molding space 26. The molding frame 36 is positioned below the sand tank 22 and is vertically movable so as to surround the nozzle 24 and squeeze foot 27. The molding frame 36 is connected to a molding frame cylinder 37 that is mounted downward on the lifting support frame 30, and is moved up and down by the molding frame cylinder 37.

[0039] The lifting support frame 30 is provided with a frame 38 located on the outside and below the sand tank 22, and an loading / unloading conveyor 39 (an example of a transport line 3) for loading and unloading the casting frame F is suspended via this frame 38. The loading / unloading conveyor 39 is composed of, for example, a roller conveyor.

[0040] Next, we will explain the molding method using the molding machine 2 described above. In this molding method, starting from the original position shown in Figure 3, sand is filled as shown in Figure 4, compressed as shown in Figure 5, and a mold removal operation is performed as shown in Figure 6. A detailed explanation follows below.

[0041] Figure 3 shows the state in which sand 23 has been added to the sand tank 22 and empty casting frames F have been loaded onto the loading / unloading conveyor 39. The pattern carrier 32 is set on the pattern changing device 31, lifted by a few millimeters by a spring (not shown), with a gap between it and the molding base 28. Next, the entire segment-type squeeze foot 27 forms bumps and grooves in relation to the bumps and grooves of the model plate 25 below. Then, the pattern carrier 32 is pressed against the molding base 28 by a clamping device (not shown).

[0042] In this state, the slide gate 33 is operated to close the sand inlet 22b, then the mold cylinder 37 extends to lower the mold 36 and press it against the upper surface of the mold F, while the mold set cylinder 29 retracts to make the mold F fit tightly against the outer circumference of the model plate 25, forming the molding space 26.

[0043] Next, compressed air is injected into the sand tank 22 from numerous holes in the filter 22a to cause the sand 23 inside the sand tank 22 to become suspend-fluid, and the sand 23 is filled into the molding space 26 formed by the casting frame F, model plate 25, build-up frame 36, squeeze foot 27, and the bottom surface of the sand tank 22, as shown in Figure 4. At this time, the compressed air used for filling is exhausted from vent holes (not shown) provided in the build-up frame 36 and model plate 25. The amount of exhaust from the vent holes can be controlled, thereby allowing for partial adjustment of the filling density of the molding sand.

[0044] Next, the frame set cylinder 29 is further retracted to retract the raised frame cylinder 37, while the lifting support frame 30 and the members supported therein are lowered, compressing the sand 23 until the entire lower surface of the segment-type squeeze foot 27 is flat. When this squeezing operation is performed, the state shown in Figure 5 is achieved.

[0045] Next, the mold is removed as shown in Figure 6. By raising the sand tank 22 and lifting the casting frame F with the loading / unloading conveyor 39, the compressed sand 23a inside the casting frame F is removed from the model plate 25. Then, the sand tank 22 and the loading / unloading conveyor 39 are raised to return to their original positions as shown in Figure 3. This movement of each component moving up and down to return to its original position is called the return to original position operation. Once the return to original position operation is complete, the slide gate 33 is activated to open the sand inlet 22b, and the sand 23 inside the sand tank 22 is replenished.

[0046] Next, the molded frame F is unloaded horizontally via the loading / unloading conveyor 39, an empty frame F is loaded, and the pattern exchange device 31 is rotated 180 degrees to replace the model plate 25 with one that is outside, and the above operation is repeated.

[0047] [Sandwich Cutter Details] Figure 7 is a front view of the sand cutter. Figure 8 is a view taken along the line VIII-VIII in Figure 7. The sand cutter 4 removes sand lumps (excess sand 1b) from the sand mold M, which is transported by the input / output conveyor 39 provided on the molding machine 2. The transported sand mold M is a mold with a frame, which is transported together with the casting frame F.

[0048] As shown in Figures 7 and 8, the sand casting mold M is transported by a transport line 3. An example of a transport line 3 is a roller conveyor. Below the roller mounting frames 3a, 3a in the transport line 3, guide rods 42, 42 are arranged opposite each other. The guide rods 42, 42 pass through holders 43, 43. The holders 43, 43 are configured to slide vertically on the guide rods 42, 42.

[0049] A lifting frame 44 is connected to the holders 43, 43, positioned between them. A blade mounting base 46, whose height can be adjusted by bolts 45, 45, is attached to the lifting frame 44. A blade 47 is detachably attached to the tip of the blade mounting base 46. A cylinder 41 is connected to the lower center of the lifting frame 44. The holders 43, 43 are configured to abut against bolts 48, 48, which act as height-adjustable stoppers at the raised end, and bolts 49, 49, which act as height-adjustable stoppers at the lowered end.

[0050] Before transporting the sand mold M, the blade 47 is raised by extending the cylinder 41. The blade 47 is then fixed at a predetermined height, and the height dimension from the back of the casting frame F to the top of the blade 47 is adjusted to the desired dimension using bolts 45, 45 and bolts 48, 48. For example, the height dimension is set to 0.5 mm. In this state, the transport line 3 transports the sand mold M by one pitch (one frame) in the transport direction D1. During transport, excess sand 1b is cut by the blade 47. As a result, the height dimension from the back of the casting frame F to the back surface MS of the sand mold M is set to 0.5 mm, and the back surface MS of the sand mold M is made flat. If it is not necessary to cut the excess sand 1b from either the upper or lower frame, the cylinder 41 can be retracted.

[0051] The sand cutter 4 is not limited to the apparatus shown in Figures 7 and 8, and various modifications are possible. For example, the sand cutter may be configured to move towards the sand mold M from a direction perpendicular to the transport direction D1 of the sand mold M. In this case, the sand cutter operates to cut the back surface MS of the sand mold M. As a more specific example, in response to receiving a frame feed completion signal from the line control unit 6, the sand cutter moves its blade toward the sand mold M to cut off excess sand from the back surface MS of the sand mold M. The sand cutter outputs a sand cut completion signal to the line control unit 6. In response to receiving the sand cut completion signal, the line control unit 6 transports the sand mold M onto the transport line 3.

[0052] [Operation of the line control unit] (Nozzle blockage detection) The line control unit 6 outputs information regarding nozzle clogging when, during sand filling in which sand from the sand tank 22 is introduced into the mold F via the nozzle 24, the pressure in the sand tank 22 is higher than the initial pressure during sand filling into the mold F. Alternatively, the line control unit 6 may output information regarding nozzle clogging when, during sand filling in which sand from the sand tank 22 is introduced into the mold F via the nozzle 24, the pressure change in the sand tank 22 is larger than the initial pressure change during sand filling into the mold F. Information regarding nozzle clogging may include letters, symbols, figures, sounds, images, vibrations, etc., indicating the occurrence of nozzle clogging. Below are some examples of how to determine if the above-mentioned relationship is satisfied.

[0053] (Example of determining pressure measured by a sensor) The line control unit 6 includes, for example, a memory 62 that stores the pressure detected by the pressure sensor PA, which is the pressure inside the sand tank 22 during the filling of sand 23. The line control unit 6 may store the pressure detected by the pressure sensor PA (measured value at the time of detection) in the memory 62 in association with time. The time associated is the time the pressure was detected. In this way, the memory 62 stores the changes in pressure. The storage location for the detected pressure and the changes in pressure may be storage 63 instead of memory 62.

[0054] The line control unit 6 obtains the pressure or pressure changes in the sand tank 22 during the filling of sand 23 by referring to the memory 62. The memory 62 pre-stores, for example, the initial pressure or initial pressure change in the sand tank 22. The initial pressure and initial pressure change are predetermined pressures and pressure changes (time changes) to detect the occurrence of nozzle clogging. For example, the initial pressure and initial pressure change are the detection results of the pressure sensor PA when sand 23 is filled into the mold F at the initial startup of the molding system 1. Initial startup may be when sand 23 is filled for the first time after factory shipment, or when sand 23 is filled for the first time on an operating day. The storage location for the initial pressure and initial pressure change may be storage 63 instead of memory 62.

[0055] The line control unit 6 refers to the memory 62 and outputs information regarding nozzle 24 clogging if the pressure detected by the pressure sensor PA is higher than the initial pressure. In this way, the line control unit 6 stores the pressure value in the storage medium and determines whether the above relationship is satisfied by comparing it with the threshold initial pressure. The line control unit 6 may also refer to the memory 62 and output information regarding nozzle 24 clogging if the pressure change detected by the pressure sensor PA is greater than the initial pressure change. In this way, the line control unit 6 may determine whether the above relationship is satisfied by storing the pressure value in the storage medium and comparing it with the threshold initial pressure change.

[0056] The line control unit 6 may refer to the memory 62 and obtain the time (arrival time) from the start of sand filling until the pressure detected by the pressure sensor PA reaches a predetermined pressure. The line control unit 6 may then output information regarding nozzle clogging when the measured arrival time is shorter than the initial arrival time obtained in advance. The predetermined pressure is a pressure predetermined to detect the occurrence of nozzle clogging, and is an example of the initial pressure. The initial arrival time is a time predetermined in correspondence with the predetermined pressure mentioned above in order to detect the occurrence of nozzle clogging. The initial arrival time is, for example, the time measured based on the detection result of the pressure sensor PA when sand 23 is filled into the mold F at the initial startup of the molding system 1. Initial startup may be when sand 23 is filled for the first time after factory shipment, when sand 23 is filled for the first time after mold change (pattern change), or when sand 23 is filled for the first time on an operating day. The storage location for the initial arrival time does not have to be memory 62; it can also be storage 63.

[0057] (Example of determining the amount of tank expansion) The line control unit 6 may include a table that correlates pressure with the amount of expansion of the sand tank 22. Such a table may be stored in memory 62 beforehand, or it may be implemented as hardware electronic circuitry. The amount of expansion of the sand tank 22 is measured using, for example, a non-contact distance sensor. Based on the amount of expansion of the sand tank 22 and the table, the line control unit 6 can obtain the pressure inside the sand tank 22. The line control unit 6 can compare the pressure inside the sand tank 22 derived from the table with the initial pressure stored in memory 62 and determine whether the pressure inside the sand tank 22 is higher than the initial pressure. Alternatively, the line control unit 6 can compare the pressure change inside the sand tank 22 derived from the table with the initial pressure change stored in memory 62 and determine whether the pressure change inside the sand tank 22 is greater than the initial pressure change. In addition to converting the amount of expansion into the pressure inside the sand tank 22 for determination, the line control unit 6 can also convert the initial pressure or initial pressure change into a threshold initial expansion amount. In this case, the line control unit 6 can determine whether the pressure in the sand tank 22 is higher than the initial pressure simply by comparing the expansion amount with the initial expansion amount. In this way, the line control unit 6 can determine whether the above relationship is satisfied based on the elapsed time. Note that when using a table, the molding machine 2 does not need to be equipped with a pressure sensor PA.

[0058] (Example of determining the amount of image change) The line control unit 6 may acquire images from a camera (not shown) that performs image recognition on the pressure sensor PA. The pressure sensor PA is, for example, an analog pressure meter. The line control unit 6 can detect if the analog pressure meter is measuring a pressure higher than the initial pressure using pattern matching technology or the like. This allows the line control unit 6 to determine whether the pressure in the sand tank 22 is higher than the initial pressure. Alternatively, the line control unit 6 may acquire the amount of image change from the difference in images over time and detect if the analog pressure meter is showing a pressure change that is greater than the initial pressure change. In this case, the line control unit 6 can determine whether the pressure change in the sand tank 22 is greater than the initial pressure change. In this way, the line control unit 6 can determine whether the above relationship is satisfied based on image recognition.

[0059] Figure 9 is a graph showing the initial pressure change of the sand tank and the pressure change at the time of detection. In the graph shown in Figure 9, the horizontal axis is time and the vertical axis is pressure. Graph G1 is the initial pressure change stored in memory 62 beforehand. The initial pressure change is a graph of the pressure change in the sand tank 22 when no nozzle clogging occurs. Graph G2 is the pressure change in the sand tank 22 detected by the pressure sensor PA. The line control unit 6 compares graph G1 and graph G2 to determine whether or not there is a nozzle clogging issue. As shown in graph G2, when nozzle clogging occurs, the pressure in the sand tank 22 changes in a characteristic manner. Specifically, the time it takes to reach a predetermined pressure (e.g., pressure P1) is shorter in graph G2 compared to graph G1. Furthermore, the maximum pressure reached is different. The line control unit 6 may determine whether or not there is a nozzle clogging issue based on the comparison of the overall characteristics described above. The line control unit 6 may also detect the occurrence of nozzle clogging based on the change in the difference between graph G1 and graph G2.

[0060] (Clearing blockage) The line control unit 6 instructs the molding machine 2 to perform a clogging removal operation when the above-described relationship of pressure or pressure change is met (i.e., when it is determined that the nozzle 24 is clogged). For example, the molding control unit 20 increases the amount of compressed air supplied into the sand tank 22 based on the instruction from the line control unit 6. This increases the pressure in the sand tank 22, which can blow away the sand 23 that is clogged in the nozzle 24.

[0061] (Alarm action) The line control unit 6 may issue an alarm if the above-described relationship between pressure or pressure change is met (i.e., if it is determined that the nozzle 24 is clogged). An alarm means notifying an operator or other person of an abnormality. As an example of alarm processing, the line control unit 6 displays a screen related to the alarm on the output unit 65. Alternatively, instead of an alarm display, or in conjunction with an alarm display, the line control unit 6 may sound an alarm through a speaker (not shown) or illuminate a warning light.

[0062] (Integration with analysis equipment) The line control unit 6 outputs information regarding the presence or absence of a blockage to the analysis device 5 when the above-described relationship of pressure or pressure change is satisfied (i.e., when it is determined that there is a blockage in the nozzle 24). The line control unit 6 may also output information regarding the presence or absence of a blockage to the analysis device 5 if the pressure in the sand tank 22, obtained from the pressure sensor PA, reaches the initial pressure earlier than a predetermined standard time. The predetermined standard time is stored in, for example, memory 62 (an example of a time storage unit). The storage location for the standard time may be storage 63 instead of memory 62. The time t3 shown in Figure 9 is the time until the pressure P1, which is a predetermined threshold, is reached. If the pressure in the sand tank 22, obtained from the pressure sensor PA, reaches the initial pressure earlier than a predetermined standard time (time t3) (for example, time t2 in the figure), the line control unit 6 assumes that the sand mold M was formed with a blockage in the nozzle 24 and outputs information regarding the presence or absence of a blockage to the analysis device 5.

[0063] The analysis device 5 changes its operation in response to information obtained from the line control unit 6 regarding the presence or absence of blockages. For example, if the analysis device 5 obtains information from the line control unit 6 regarding the presence or absence of blockages, it operates the external force application device 52 to apply air pressure to the sand mold M before imaging the sand mold M. The external force application device 52 applies an airflow rate (800 L / min) sufficient to move the sand to the sand mold M before imaging the sand mold M. This allows the external force application device 52 to move the sand adhering to the surface of the sand mold M, exposing the surface of the object to be inspected. Alternatively, if the analysis device 5 obtains information from the line control unit 6 regarding the presence or absence of blockages, it may image the sand mold M in high-magnification mode. In this way, if information regarding the presence or absence of blockages is obtained, the analysis device 5 can operate to perform a more careful analysis.

[0064] (Integration with a sand cutter) The line control unit 6 determines whether the squeeze has been completed successfully based on the detection result (squeeze pressure) of the pressure sensor PB. For example, the line control unit 6 compares the pressure obtained during normal operation with the detection result of the pressure sensor P, and determines that the squeeze has not been completed successfully if the detection result is below a threshold. The sand cutter 4 changes its operation depending on whether or not the nozzle 24 is clogged and whether or not the squeeze has been completed successfully.

[0065] For example, in the case of normal completion (when the line control unit 6 determines that there is no clogging of the nozzle 24 and that the squeeze has been completed successfully), the line control unit 6 operates the transport line 3 so that the relative speed between the sand mold M and the cutter member 53 is a first speed. Then, in the case of abnormal completion (when the line control unit 6 determines that there is clogging of the nozzle 24 and that the squeeze has not been completed successfully), the line control unit 6 operates the transport line 3 so that the relative speed between the sand mold M and the cutter member 53 is a second speed, which is lower than the first speed. If the sand cutter 4 has a moving configuration, the sand cutter 4 operates the cutter member 53 so that the relative speed between the sand mold M and the cutter member 53 is a first speed in the case of normal completion. Then, in the case of abnormal completion, the sand cutter 4 operates the cutter member 53 so that the relative speed between the sand mold M and the cutter member 53 is a second speed, which is lower than the first speed.

[0066] (Summary of the embodiments) According to the molding system 1, during sand filling, in which sand 23 from the sand tank 22 is introduced into the mold F via the nozzle 24, if the time from the start of sand filling to reaching a predetermined pressure is shorter than the initial pressure arrival time acquired in advance, information regarding nozzle clogging is output. In this way, nozzle clogging is detected mechanically, so this molding system can detect the occurrence of nozzle clogging more appropriately than when judged by an operator.

[0067] The molding system 1 performs an operation to clear the nozzle 24 when the above-described relationship of pressure or pressure change is satisfied (i.e., when it is determined that the nozzle 24 is clogged), thereby preventing molding defects from occurring due to insufficient sand filling caused by nozzle clogging.

[0068] The molding system 1 issues an alarm when the above-described relationship of pressure or pressure change is met (i.e., when it is determined that the nozzle 24 is clogged), thereby notifying the operator or others that the nozzle 24 is clogged.

[0069] The molding system 1 outputs information regarding the presence or absence of clogging to the analysis device 5 when the above-described relationship of pressure or pressure change is met (i.e., when it is determined that the nozzle 24 is clogged). Therefore, the molding system 1 can perform image analysis of the sand mold M that was molded when the nozzle 24 was clogged.

[0070] If the above-described relationship between pressure or pressure change is met (i.e., if it is determined that the nozzle 24 is clogged), the molding system 1 applies pneumatic pressure to the sand mold M using the external force application device 52 before imaging the sand mold M. As a result, the molding system 1 can move and remove the sand that has fallen onto the surface of the sand mold M using pneumatic pressure.

[0071] When the analysis device 5 acquires information regarding the presence or absence of clogging of the nozzle 24, it images the sand mold M in high-magnification mode, allowing for more detailed image analysis of the sand mold M formed when the nozzle 24 was clogged.

[0072] The sand cutter 4 takes into account the hardness (mold strength) of the sand mold M in the case where the squeeze was completed successfully and the case where the squeeze was not completed successfully, and changes its operation depending on whether the squeeze was completed successfully or not. This allows the sand cutter 4 to avoid collapsing the sand mold M.

[0073] If the sand cutter 4 determines that the nozzle 24 is clogged and that the squeeze has not been completed properly, it slows down the relative speed between the sand mold M and the cutter member 53 compared to when the squeeze was completed properly. This allows the sand cutter 4 to avoid damaging the sand mold M.

[0074] The embodiments described above are merely examples of molding systems according to this disclosure. The molding systems according to this disclosure are not limited to molding system 1 according to the embodiments, and may be modified or applied to other systems without changing the gist of each claim. For example, molding system 1 has been described in which compressed air is ejected from a plurality of holes in a filter 22a on the inner surface of a sand tank 22 to fill the molding space 26 with sand 23 while causing the sand 23 to float and flow (aeration method), but is not limited to this. The molding system according to this disclosure may also employ a blow method in which compressed air is supplied to the sand tank 22 and the sand is blown into the mold by pressure. [Explanation of Symbols]

[0075] 1…Molding system, 2…Molding machine, 3…Conveyor line, 4…Sand cutter, 5…Analysis device, 6…Line control unit, 21…Sensor, 22…Sand tank (example of a tank), 24…Nozzle, M…Sand mold, F…Casting frame, B…Surface plate

Claims

1. A molding system for creating sand molds, Casting frame and A tank connected to a compressed air source, with an open end, and containing sand inside, A nozzle attached to the end of the tank, which guides the sand inside the tank into the casting frame, During sand filling, in which sand from the tank is introduced into the casting frame via the nozzle, a control unit outputs information regarding nozzle clogging when the time from the start of sand filling to reaching a predetermined pressure is shorter than the initial pressure to be reached, which is obtained in advance. A molding system equipped with the following features.

2. The molding system according to claim 1, wherein the control unit performs an operation to clear the nozzle blockage when the above relationship is satisfied.

3. The molding system according to claim 1 or 2, wherein the control unit provides an alarm when the relationship is satisfied.

4. The device includes an analysis apparatus that images the sand mold and performs an external inspection of the sand mold based on the captured image. The molding system according to any one of claims 1 to 3, wherein the control unit outputs the information to the analysis device when the relationship is satisfied.

5. The molding system according to claim 4, wherein the analysis device further comprises an external force application device that applies pneumatic pressure to the sand mold before imaging the sand mold when the analysis device has acquired the information from the control unit.

6. The molding system according to claim 4 or 5, wherein the analysis device is configured to switch between a standard mode for imaging the sand mold at a first magnification and a high-magnification mode for imaging the sand mold at a magnification higher than the first magnification, and when the information is obtained from the control unit, the sand mold is imaged at least in the high-magnification mode.

7. A squeeze mechanism for squeezing the sand filled in the mold, A sand cutter for shaping the sand mold, A pressure sensor that detects squeeze pressure, Equipped with, The control unit determines, based on the detection result of the pressure sensor, whether the squeeze by the squeeze mechanism has been completed successfully. The molding system according to any one of claims 1 to 6, wherein the sand cutter changes its operation depending on whether or not the nozzle is clogged and whether or not the squeeze has been completed successfully.

8. The aforementioned sand cutter is If the above relationship is not satisfied and the control unit determines that the squeeze has been completed successfully, the relative speed between the sand mold and the blade will be set to the first speed. The molding system according to claim 7, wherein if the above relationship is satisfied and the control unit determines that the squeeze has not been completed normally, the relative speed between the sand mold and the blade is operated to a second speed lower than the first speed.

9. A process of introducing sand from a tank connected to a compressed air source, with an open end and containing sand, into a casting mold via a nozzle attached to the end of the tank, In the process of introducing the material into the mold, when the time from the start of sand filling to reaching a predetermined pressure is shorter than the initial time to reach that pressure which has been acquired in advance, the process of outputting information regarding the clogging of the nozzle, A molding method comprising the following features.

Images