A high-frequency, low-amplitude volume control quantitative sand spreading device and method for sand mold additive manufacturing

Abstract

This invention provides a high-frequency, low-amplitude volume-controlled quantitative sand-laying device and method for sand mold additive manufacturing. The device includes a sand-dropping mechanism, a sand-laying mechanism, and a baffle mechanism. The sand-dropping mechanism uses ultrasonic pulse vibration to ensure uniform sand distribution onto a conveyor belt. The sand-laying mechanism adjusts the conveyor belt speed via a speed controller. The baffle mechanism controls the sand layer thickness and directs the sand particles downwards via baffles. This invention effectively achieves quantitative, controllable, and adjustable sand laying, improving overall sand laying quality and saving materials. It can further promote the development of quantitative, controllable, and adjustable sand laying in sand mold printing.

Description

Technical Field

[0001] This invention belongs to the field of 3DP additive printing technology, specifically relating to a high-frequency, low-amplitude volume control quantitative sand spreading device and method for sand mold additive manufacturing. Background Technology

[0002] With the increasing global production of castings, the variety and quality requirements of castings are becoming more diverse. Traditional mold-making methods for producing single, small-batch, thin-walled, complex castings are significantly outdated in terms of cost and time, lagging behind the development needs of enterprises. Sand-based additive manufacturing technology, which involves slicing the three-dimensional model of the casting mold and then using micro-droplet spraying to create a sand mold layer by layer, offers a fast response time and low manufacturing cost, attracting increasing attention.

[0003] The development of sand mold 3D printing technology marks the rapid industrialization of small-batch castings. Currently, the sand quantity adjustment in sand spreaders on the market is achieved through coarse adjustments by controlling the size of the sand outlet and the opening and closing time of the sand feeder. This cannot achieve precise adjustment of the sand quantity, easily leading to quality problems such as low surface smoothness and high porosity. It also generates excessive molding sand, resulting in resource waste, increased costs, and environmental pollution. The patent application CN201710550322.7, "An Adjustable Sand Feeding Mechanism for a 3D Printing Sand Spreader," discloses a method to achieve controllable and adjustable sand quantity through vibration-based sand feeding. However, due to the inherent instability of the vibration mechanism, the non-adjustable sand feeding speed, and the varying fluidity of the multi-material molding sand mixed with a curing agent, the angle of the corresponding adjustment plate needs to be adjusted. Therefore, current quantitatively controllable and adjustable sand spreading structures struggle to spread molding sand of different materials and particle sizes, and the corresponding sand feeding speed is difficult to match the overall movement speed of the sand spreading process. Therefore, in order to meet the current needs of green, intelligent, efficient quantitative sand spreading, there is an urgent need for a quantitative sand spreading mechanism that can meet the requirements of multiple materials and multiple particle sizes of molding sand. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-frequency, low-amplitude volume control quantitative sand spreading device and method for sand mold additive manufacturing, which addresses the shortcomings of the prior art. The device uses ultrasonic vibration to drop the medium sand in the sand storage tank onto the conveyor belt, and achieves quantitative sand spreading by controlling the belt drive speed and the overall sand spreading device movement speed. The sand spreading speed and the thickness of each layer of sand can be adjusted during the sand spreading process, thereby achieving precise quantitative sand spreading for each layer.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a sand casting additive manufacturing high-frequency low-amplitude volume control sand spreading device, characterized in that it includes a sand dropping mechanism, a sand spreading mechanism and a baffle mechanism;

[0006] The sand removal mechanism includes a sand reservoir, an ultrasonic generator, and a transducer. The sand reservoir is mounted on a main support plate via a connecting plate. The transducer is mounted on the support plate and is fixedly connected to the sand reservoir. The transducer is connected to the ultrasonic generator via a serial cable.

[0007] The sand spreading mechanism includes a conveyor belt, which is disposed below the sand storage container and is driven by a belt drive device.

[0008] The baffle mechanism includes a front baffle plate and a rear baffle plate. The front baffle plate is located at the front end of the conveyor belt and maintains a distance from the conveyor belt. The rear baffle plate is located above the conveyor belt and the distance between the rear baffle plate and the conveyor belt is adjustable. Baffles are provided on both sides of the conveyor belt. A vibrator is installed on the front baffle plate.

[0009] Preferably, the sand storage container is an open container with an open top and bottom. A metal screen is bonded to the bottom of the sand storage container. The mesh diameter of the metal screen is slightly larger than the particle size of the molding sand. The transducer is fixedly installed on the main support plate by a vibration isolation collar. A vibration isolation pad is provided between the sand storage container and the connecting plate.

[0010] Preferably, the belt drive device includes a conveyor roller, a synchronous pulley, a synchronous belt, and a motor. Multiple conveyor rollers are arranged inside the conveyor belt and drive the belt to move by friction. The conveyor rollers are mounted on two support seats by bearings. One end of one conveyor roller is coaxially fixedly mounted with a synchronous pulley. The output shaft of the motor is connected to the synchronous pulley through a reducer. A synchronous belt is connected between the two synchronous pulleys. The motor is connected to a speed regulator. The reducer, motor, and speed regulator are fixedly mounted on a horizontal plate. The horizontal plate is fixedly mounted on a main support plate.

[0011] Preferably, a scraper seat is fixedly installed on the support base, and a scraper is installed on the scraper seat. The length of the scraper, the length of the sand storage device, and the width of the conveyor belt are equal.

[0012] Preferably, the front sand baffle is fixedly installed on the front support, the front support is movably installed between two support seats, and a fixing plate is fixedly installed on the front support.

[0013] Preferably, the distance between the rear sand baffle and the conveyor belt is adjustable from 4 to 6 mm, the distance between the rear sand baffle and the sand storage device is 4 cm, the height of the rear sand baffle is 30 mm, the width of the rear sand baffle is 20 mm, and the length of the rear sand baffle is equal to the width of the conveyor belt.

[0014] Preferably, the vibrator is a mechanical vibration device or an ultrasonic vibration device. When it is an ultrasonic vibration device, a metal screen is used for the front sand baffle, and the mesh size of the metal screen is smaller than the particle size of the molding sand.

[0015] A method for high-frequency, low-amplitude volumetric sand-laying control in sand mold additive manufacturing includes the following steps:

[0016] S1. Adjust the distance between the rear baffle plate and the front baffle plate and the conveyor belt according to the particle size of the molding sand, and add molding sand mixed with curing agent to the sand storage tank.

[0017] S2. Turn on the ultrasonic generator to generate vibration on the sand storage tank, so that the molding sand falls onto the conveyor belt.

[0018] S3. Turn on the motor and vibrator. The transmission belt moves so that the molding sand particles pass through the rear baffle plate and flow out a molding sand layer of a certain thickness. After the motor starts for t seconds, the surface sand is laid for printing.

[0019] Preferably, in S3, after the motor starts for t seconds...

[0020] t=(d+s) / v

[0021] Where d is the distance from the sand drop outlet to the sand storage container, s is the distance from the conveyor belt to the printing surface, v is the speed of the conveyor belt, and the overall sand spreading device moves at the same speed as the conveyor belt.

[0022] The pulse vibration frequency of the ultrasonic vibration generator is t1 times / min.

[0023] t1=h*l*v / c

[0024] Where l is the width of the conveyor belt, and c is the volume of molding sand falling onto the conveyor belt per minute after the ultrasonic vibration is turned on.

[0025] Preferably, the vibration frequency of the vibrator is 3MHz to 6MHz, and the vibration amplitude is 0.01mm to 1mm.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. This invention uses ultrasonic pulse vibration to drop sand onto the conveyor belt, which can prevent the molding sand particles from sticking together and reducing the quality of sand spreading. At the same time, the ultrasonic vibration sand dropping is controllable and adjustable to meet the sand dropping amount at different conveyor belt speeds. Furthermore, the use of ultrasonic vibration sand dropping can ensure that the molding sand falls evenly onto the conveyor belt, avoiding the problem of insufficient molding sand on both sides of the sand storage tank due to the sand sticking together, which would affect the quality of sand spreading.

[0028] 2. This invention achieves controllable and adjustable quantitative dropping of molding sand by using belt drive and adjustable sand baffle, ensuring the smoothness and quality of sand laying under different fluidity materials.

[0029] 3. The sand baffle plate with vibrator used in this invention can prevent the molding sand from sticking to the sand baffle plate during the falling process on the conveyor belt, which is conducive to the vertical falling of molding sand particles. At the same time, the scraper can prevent molding sand particles from sticking to the conveyor belt.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0032] Figure 2 This is a top-view structural schematic diagram of the invention from a first perspective.

[0033] Figure 3 This is a top-view structural schematic diagram of the second perspective of the present invention.

[0034] Figure 4 This is a side view structural diagram of the present invention.

[0035] Figure 5 This is a side view schematic diagram of the structure for adjusting the distance between the sand baffle and the conveyor belt in this invention.

[0036] Figure 6 This is a schematic diagram of the main structure for adjusting the distance between the sand baffle and the conveyor belt in this invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1—Sand reservoir; 2—Transducer; 3—Vibration isolation collar;

[0039] 4—Connecting plate; 5—Ultrasonic generator; 6—Horizontal plate;

[0040] 7—Main support plate; 8—Support seat; 9—Partition plate;

[0041] 10—Conveyor roller; 11—Rear baffle plate; 12—Conveyor belt;

[0042] 13—Metal mesh screen; 14—Vibration damping pad; 15—Synchronous pulley;

[0043] 16—Synchronous belt; 17—Gear reducer; 18—Motor;

[0044] 19—Speed ​​controller; 20—Front baffle plate; 21—Vibrator;

[0045] 22—Fixed plate; 23—Front support; 24—Scraper seat;

[0046] 25—Scraper; 26—Bearing. Detailed Implementation

[0047] Example 1

[0048] like Figures 1 to 6 As shown, this embodiment includes a high-frequency, low-amplitude volume control quantitative sand spreading device for sand mold additive manufacturing, comprising a sand dropping mechanism, a sand spreading mechanism, and a baffle mechanism;

[0049] The sand removal mechanism includes a sand storage device 1, an ultrasonic generator 5, and a transducer 2. The sand storage device 1 is mounted on the main support plate 7 via a connecting plate 4. The transducer 2 is mounted on the support plate 7 and is fixedly connected to the sand storage device 1. The transducer 2 is connected to the ultrasonic generator 5 via a serial cable.

[0050] The sand-laying mechanism includes a conveyor belt 12, which is disposed below the sand storage device 1 and is driven by a belt drive device.

[0051] The baffle mechanism includes a front baffle plate 20 and a rear baffle plate 11. The front baffle plate 20 is disposed at the front end of the conveyor belt 12 and is spaced apart from the conveyor belt 12. The rear baffle plate 11 is disposed above the conveyor belt 12 and the distance between the rear baffle plate 11 and the conveyor belt 12 is adjustable. Partition plates 9 are disposed on both sides of the conveyor belt 12. A vibrator 21 is installed on the front baffle plate 20.

[0052] In this embodiment, the sand storage container 1 is an open container with an open top and bottom. A metal screen 13 is bonded to the bottom of the sand storage container 1. The mesh diameter of the metal screen 13 is slightly larger than the particle size of the molding sand. The transducer 2 is fixedly installed on the main support plate 7 by a vibration isolation collar 3. A vibration isolation pad 14 is provided between the sand storage container 1 and the connecting plate 4. The vibration isolation collar 3 and the vibration isolation pad 14 are made of silicone and have a thickness of 3mm.

[0053] In this embodiment, the belt drive device includes a conveyor roller 10, a synchronous pulley 15, a synchronous belt 16, and a motor 18. Multiple conveyor rollers 10 are arranged inside the conveyor belt 12 and drive the conveyor belt 12 to move by friction. The conveyor rollers 10 are mounted on two support seats 8 through bearings 26. One end of one conveyor roller 10 is coaxially fixedly mounted with a synchronous pulley 15. The output shaft of the motor 18 is connected to the synchronous pulley 15 through a reducer 17. A synchronous belt 16 is connected between the two synchronous pulleys 15. The motor 18 is connected to a speed regulator 19. The reducer 17, the motor 18, and the speed regulator 19 are fixedly mounted on a horizontal plate 6. The horizontal plate 6 is fixedly mounted on a main support plate 7.

[0054] In this embodiment, a scraper seat 24 is fixedly installed on the support seat 8, and a scraper 25 is installed on the scraper seat 24. The length of the scraper 25, the length of the sand storage device 1, and the width of the conveyor belt 12 are equal.

[0055] In this embodiment, the front sand baffle 20 is fixedly installed on the front support 23, the front support 23 is movably installed between two support seats 8, and the fixing plate 22 is fixedly installed on the front support 23.

[0056] In this embodiment, the distance between the rear baffle plate 11 and the conveyor belt 12 is adjustable by 5mm; the distance between the rear baffle plate 11 and the sand reservoir 1 is 4cm; the height of the rear baffle plate 11 is 30mm; the width of the rear baffle plate 11 is 20mm; the length of the rear baffle plate 11 is equal to the width of the conveyor belt 12; and the top of the scraper 25 is 0.5mm from the conveyor belt.

[0057] In this embodiment, the vibrator 21 is a mechanical vibration device or an ultrasonic vibration device. When it is an ultrasonic vibration device, the front baffle plate 20 uses a metal screen, and the mesh size of the metal screen is smaller than the particle size of the molding sand.

[0058] Example 2

[0059] A method for quantitative sand spreading with high-frequency, low-amplitude volume control in sand mold additive manufacturing includes the following steps:

[0060] S1. Adjust the distance between the rear baffle plate 11 and the front baffle plate 20 and the conveyor belt 12 according to the particle size of the molding sand, and add molding sand mixed with curing agent to the sand storage tank 1.

[0061] S2. Turn on the ultrasonic generator 5 to generate vibration on the sand storage tank 1, so that the molding sand falls onto the conveyor belt 12.

[0062] S3. Start the motor 18 and vibrator 21. The transmission belt 12 moves so that the molding sand particles pass through the rear baffle plate 11 and flow out a molding sand layer of a certain thickness. After the motor 18 starts for t seconds, the surface sand is laid for printing.

[0063] In this embodiment, after motor 18 starts for t seconds in S3...

[0064] t = (d + s) / v = (90 + 10) / 50 = 2

[0065] Where d = 90 mm is the distance from the sand drop outlet to the sand storage device 1, s = 10 mm is the distance from the conveyor belt 12 to the printing surface, v = 50 mm / s is the moving speed of the conveyor belt 12, and the moving speed of the overall sand spreading device is equal to the moving speed of the conveyor belt.

[0066] The pulse vibration frequency of the ultrasonic vibration generator is t1 times / min.

[0067] t1=h*l*v / c=4*50*50 / 100=10

[0068] Where l = 50mm is the width of conveyor belt 12, the conveyor belt speed v = 50mm / s, and c = 100mm3 This refers to the volume of molding sand falling onto the conveyor belt per minute after ultrasonic vibration is activated.

[0069] In this embodiment, the vibration frequency of the vibrator 21 is 3MHz to 6MHz, and the vibration amplitude is 0.01mm to 1mm.

[0070] In this embodiment, the distance between the rear baffle 11 and the conveyor belt 12 can be adjusted by adjusting the up and down movement of the rear baffle 11 and fixing it with the partition 9. At the same time, the distance between the front baffle 20 and the conveyor belt 12 can be adjusted by adjusting the front support 23.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A sand-laying method for a sand-laying device for high-frequency, low-amplitude volume control in sand-mold additive manufacturing, characterized in that, The sand-laying device includes a sand-dropping mechanism, a sand-laying mechanism, and a baffle mechanism; The sand removal mechanism includes a sand reservoir (1), an ultrasonic generator (5), and a transducer (2). The sand reservoir (1) is mounted on the main support plate (7) via a connecting plate (4). The transducer (2) is mounted on the main support plate (7). The transducer (2) is fixedly connected to the sand reservoir (1). The transducer (2) is connected to the ultrasonic generator (5) via a serial cable. The sand-laying mechanism includes a conveyor belt (12), which is located below the sand storage device (1) and is driven by a belt drive device. The baffle mechanism includes a front baffle plate (20) and a rear baffle plate (11). The front baffle plate (20) is located at the front end of the conveyor belt (12) and is spaced apart from the conveyor belt (12). The rear baffle plate (11) is located above the conveyor belt (12) and the distance between the rear baffle plate (11) and the conveyor belt (12) is adjustable. The conveyor belt (12) is provided with partitions (9) on both sides. A vibrator (21) is installed on the front baffle plate (20). The distance between the rear baffle plate (11) and the conveyor belt (12) is adjustable from 4 to 6 mm. The distance between the rear baffle plate (11) and the sand storage device (1) is 4 cm. The height of the rear baffle plate (11) is 30 mm. The width of the rear baffle plate (11) is 20 mm. The length of the rear baffle plate (11) is equal to the width of the conveyor belt (12). The sand-laying method includes the following steps: S1. Adjust the distance between the rear baffle plate (11) and the front baffle plate (20) and the conveyor belt (12) according to the particle size of the molding sand, and add molding sand mixed with curing agent to the sand storage tank (1). S2. Turn on the ultrasonic generator (5) to generate vibration on the sand storage container (1) so that the molding sand falls onto the conveyor belt (12). S3. Start the motor (18) and vibrator (21). The conveyor belt (12) moves so that the molding sand particles pass through the back baffle (11) and flow out a molding sand layer of a certain thickness. The motor (18) starts printing surface sand after t seconds. After motor (18) starts for t seconds ； Where d is the distance from the sand drop outlet to the sand storage container, mm; s is the distance from the conveyor belt to the printing surface, mm; v is the conveyor belt speed, mm / s; and the overall sand spreading device's moving speed is equal to the conveyor belt's moving speed. The pulse vibration frequency of the ultrasonic vibration generator is t1 times / min. ； Wherein, l is the width of the conveyor, mm; c is the volume of the sand falling on the conveyor per minute after the ultrasonic vibration is turned on, mm 3 ; h is the distance between the sand backstop (11) and the conveyor (12), mm; The vibration frequency of the vibrator (21) is 3MHz~6MHz and the vibration amplitude is 0.01mm~1mm.

2. The sand-laying method of the sand-laying device for high-frequency, low-amplitude volume control in sand-mold additive manufacturing according to claim 1, characterized in that, The sand storage container (1) is an open container with an open top and bottom. A metal screen (13) is provided on the bottom surface of the sand storage container (1). The transducer (2) is fixedly installed on the main support plate (7) by a vibration isolation collar (3). A vibration isolation pad (14) is provided between the sand storage container (1) and the connecting plate (4).

3. The sand-laying method of the sand-laying device for high-frequency, low-amplitude volume control in sand-mold additive manufacturing according to claim 1, characterized in that, The belt drive device includes a conveyor roller (10), a synchronous pulley (15), a synchronous belt (16), and a motor (18). Multiple conveyor rollers (10) are arranged inside the conveyor belt (12) and drive the conveyor belt (12) to move by friction. The conveyor rollers (10) are mounted on two support seats (8) through bearings (26). One end of one conveyor roller (10) is coaxially fixedly mounted with a synchronous pulley (15). The output shaft of the motor (18) is connected to the synchronous pulley (15) through a reducer (17). A synchronous belt (16) is connected between the two synchronous pulleys (15). The motor (18) is connected to a speed regulator (19). The reducer (17), the motor (18), and the speed regulator (19) are fixedly mounted on a horizontal plate (6). The horizontal plate (6) is fixedly mounted on a main support plate (7).

4. The sand-laying method of the sand-laying device for high-frequency, low-amplitude volume control in sand-mold additive manufacturing according to claim 3, characterized in that, The support seat (8) is fixedly installed with a scraper seat (24), and a scraper (25) is installed on the scraper seat (24). The length of the scraper (25), the length of the sand storage device (1), and the width of the conveyor belt (12) are equal.

5. The sand-laying method of the sand-laying device for high-frequency, low-amplitude volume control in sand-mold additive manufacturing according to claim 1, characterized in that, The front sand baffle (20) is fixedly installed on the front support (23), the front support (23) is movably installed between two support seats (8), and the fixing plate (22) is fixedly installed on the front support (23).

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