A 3D printing sand spreader noise reduction device and method

Abstract

The application discloses a 3D printing sand spreader noise reduction device and method, which comprises an active noise reduction module and soundproof covers located on both sides of the sand spreader; the soundproof cover comprises, from inside to outside, a protective layer for blocking, a sound absorption layer and a sound insulation layer for reducing noise, a damping layer for preventing resonance of the soundproof cover, and a soundproof cover wall, so as to block the noise generated by the sand spreader; the active noise reduction module comprises a controller, a primary microphone array, a secondary loudspeaker and an error microphone; the primary microphone array receives the noise signal blocked by the soundproof cover and transmits the noise signal to the controller; the controller analyzes the noise signal after blocking, controls the secondary loudspeaker to emit sound waves with the same amplitude and opposite phase as the noise signal after blocking, and adjusts the sound waves emitted by the secondary loudspeaker according to the feedback signal transmitted by the error microphone to the controller. The application reduces the noise in the working area of the 3D printer, finds safety hazards, improves the working environment of workers and improves the noise reduction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printer noise reduction, in particular to a 3D printing sand spreader noise reduction device and method. BACKGROUND

[0002] For a certain casting sand type 3D printer, the sand spreader is the main noise source component of the casting sand type 3D printer, and the vibration motor driving V-shaped groove vibration is the main reason for the noise generated by the sand spreader. The vibration motor speed is from 1000 to 5000 r / min, and a gear is set every 1000 r / min. The higher the gear, the higher the vibration motor speed, and the greater the noise. According to the measurement, the local noise of the V-shaped groove near field reaches 94 dB, the main noise frequency band is 60-2000 Hz, the noise sound pressure level is large, and the frequency coverage is wide. Noise not only affects hearing, but also has a great harm to the nervous system of human beings. People in a noisy environment for a long time will have many health problems, including insomnia, tinnitus, headache, cardiovascular problems, and low immunity. Working and studying in a noisy environment will lead to inattention, causing psychological discomfort and mental health problems. In addition, the noise environment will also affect communication, easily cause misunderstanding and conflict, and also affect ecology and animal protection.

[0003] To prevent noise hazards, workers often wear ear muffs or install soundproof covers on equipment, fill soundproof foam, etc. Such methods will eliminate some high-frequency noise. Traditional soundproof covers have good effect on high-frequency noise, but the effect on low-frequency noise is not very obvious. Moreover, the traditional single-layer soundproof cover has a large volume, poor adaptability to different environments, and the installation of the soundproof cover affects the visibility and monitoring of the noise source.

[0004] For low-frequency noise, an active noise reduction device is often used. The fundamental is to emit a sound wave with the same amplitude and opposite phase as the noise source through artificial control of the secondary sound source, so as to weaken the noise in a certain area according to the principle of sound wave interference or radiation suppression. The active noise reduction device cannot completely eliminate all types of noise. It has good noise reduction effect in a specific frequency range, but may have poor effect in other frequencies. Moreover, relying solely on the active noise reduction system to reduce noise has high cost and energy consumption.

[0005] Therefore, the present application aims to reduce both high-frequency noise and low-frequency noise generated by the 3D printing sand spreader. SUMMARY

[0006] To solve the above problems, the present application provides a 3D printing sand spreader noise reduction device and method, which aims to realize the noise reduction of the 3D printing sand spreader through the soundproof cover and the active noise reduction module.

[0007] The technical scheme adopted by the present application to solve the technical problems is:

[0008] The application provides a 3D printing sand spreader noise reduction device, which comprises an active noise reduction module and soundproof covers located on both sides of the sand spreader.

[0009] The soundproof cover comprises, from the inside to the outside, a protective layer for blocking, a sound absorption layer and a sound insulation layer for reducing noise, a damping layer for preventing resonance of the soundproof cover, and a soundproof cover wall for blocking the noise generated by the sand spreader.

[0010] The active noise reduction module comprises a controller, a primary microphone array, an error microphone and an angle-adjustable secondary loudspeaker. The primary microphone array receives the noise signal blocked by the soundproof cover and transmits it to the controller. The controller analyzes the blocked noise signal and controls the secondary loudspeaker to emit sound waves with the same amplitude and opposite phase as the blocked noise. The controller adjusts the sound waves emitted by the secondary loudspeaker in real time according to the feedback signal transmitted by the error microphone.

[0011] Further, the sand spreader comprises a V-shaped groove, a transmission rod, a cam mechanism arranged on the transmission rod, and a vibration motor connected to one end of the transmission rod. The vibration motor drives the cam mechanism to vibrate through the transmission rod. The cam mechanism is connected to the V-shaped groove, so that the V-shaped groove vibrates and generates noise.

[0012] Further, the sand spreader further comprises a sand storage groove 64, which comprises an axially arranged sand storage groove side wall and a sand storage groove end plate located at the end of the sand storage groove side wall. The sand storage groove side wall and the sand storage groove end plate cooperate to form a sand storage groove cavity, which is connected to the V-shaped groove.

[0013] The sand spreader is provided with a sand spreader beam on both sides, and the soundproof cover is provided with an upper clamp and a lower clamp at both ends. The upper clamp and the lower clamp make the layers of the soundproof cover tightly fit. The upper clamp is provided with a bolt hole for bolt connection of the soundproof cover to the sand spreader beam.

[0014] The soundproof cover is curved outwardly in an arc shape, which cooperates with the sand spreader to form a semi-closed structure. The semi-closed structure is located on both sides of the V-shaped groove and shields the two side surfaces of the V-shaped groove. The two ends of the semi-closed structure are connected to the outside.

[0015] Further, the controller comprises a control unit, a storage unit, a signal processing unit and a warning unit.

[0016] The signal processing unit analyzes the blocked noise signal to determine the noise source direction, amplitude and frequency. According to the processing result of the signal processing unit, the control unit controls the secondary loudspeaker to emit sound waves with the same amplitude and opposite phase as the blocked noise signal.

[0017] The storage unit is used for storing a predetermined noise reduction scheme and a fault noise signal, the predetermined noise reduction scheme including a vibration motor rotating speed, a printing sand type, and a sound emitting angle and a sound wave emitted by a secondary loudspeaker at the rotating speed;

[0018] The active noise reduction module includes adjusting the sound emitting angle and the sound wave emitted by the secondary loudspeaker in real time on site, i.e. a field mode, and calling the predetermined noise reduction scheme stored in the storage unit, i.e. an automatic mode; in the automatic mode, when the vibration motor rotating speed and the printing sand type during the operation of the printer are consistent with the vibration motor rotating speed and the printing sand type in the stored noise reduction scheme, the controller automatically calls the stored predetermined noise reduction scheme, quickly adjusts the sound emitting angle of the secondary loudspeaker, and emits the sound wave in the corresponding predetermined noise reduction scheme;

[0019] When the primary microphone array receives the fault noise signal or cannot achieve the expected noise reduction effect, the early warning unit issues an alarm to remind the staff to check.

[0020] Further, the primary microphone array includes microphones distributed in multiple rows and columns, and the controller evaluates the noise source position according to the microphone distribution geometric information, the noise environment, and the time difference of the noise signals received by each microphone.

[0021] Further, the 3D printing sand spreader noise reduction device further includes a box with sound insulation cotton laid on the inner wall, the sand spreader is accommodated in the box, the primary microphone array is connected to the inner wall above the middle part of the sand spreader, the secondary loudspeaker is connected to the inner side wall opposite to the end part of the sand spreader, the error microphone is arranged on the outer wall of the box, and the controller is arranged outside the box.

[0022] Further, the secondary loudspeaker includes a loudspeaker body, a rotating member connected to the loudspeaker body, and a loudspeaker base, the secondary loudspeaker is detachably connected to the inner side wall of the box through the loudspeaker base, and the loudspeaker body is transversely and vertically rotated through the rotating member.

[0023] Further, the rotating member includes a fixed shaft arranged on the loudspeaker base, a rotating block rotating around the fixed shaft, and a rotating shaft arranged on the rotating block, the loudspeaker body is connected to the outer end of the rotating shaft, the loudspeaker body is vertically rotated through the rotating block rotating around the fixed shaft, and the loudspeaker body is transversely rotated through the rotating shaft.

[0024] Further, the protective layer is a steel plate, the sound absorption layer is a porous structure made of glass wool, the sound insulation layer is a PU adhesive sound insulation pad, the damping layer is made of asphalt damping material, and the sound insulation cover wall is made of S45 steel.

[0025] The application also provides a 3D printing sand spreader noise reduction method, which is applied to the 3D printing sand spreader noise reduction device.

[0026] S1: soundproof covers are installed on both sides of the sand spreader, and an active noise reduction module is installed on the box body;

[0027] S2: after the printer is started, part of the noise generated by the sand spreader is blocked by the soundproof cover;

[0028] S3: the primary microphone array receives the noise signal blocked in step S2 and transmits it to the controller;

[0029] S4: the controller filters and calculates the noise signal received by the primary microphone array, processes the signal, judges the noise source direction, amplitude and frequency;

[0030] S5: according to the noise source direction, amplitude and frequency in step S4, the controller controls the secondary loudspeaker to emit sound waves with the same propagation path, opposite phase, same amplitude as the noise signal of the noise source, and adjusts the secondary loudspeaker to the appropriate sound emitting angle through the rotating member to realize noise reduction;

[0031] S6: the controller receives the feedback signal, i.e. the residual noise signal, returned by the error microphone in real time, analyzes the residual noise signal, and continuously adjusts the sound emitting angle, sound wave phase and amplitude of the secondary loudspeaker until the optimal noise reduction effect is achieved;

[0032] S7: the noise reduction scheme under a specific rotating speed is set as a predetermined noise reduction scheme stored in the controller, including the rotating speed of the vibration motor, the type of printing sand and the sound emitting angle and sound waves emitted by the secondary loudspeaker under the rotating speed, when the rotating speed of the vibration motor and the type of printing sand are consistent with the rotating speed of the vibration motor and the type of printing sand in the stored noise reduction scheme, the controller automatically calls the stored predetermined noise reduction scheme, quickly adjusts the sound emitting angle of the secondary loudspeaker, and emits corresponding sound waves; the fault noise signal of the equipment is stored in the controller, when the primary microphone array receives the fault noise signal or cannot achieve the expected noise reduction effect, the controller issues an alarm to remind the staff to check;

[0033] S8: the noise after being reduced by the active noise reduction module is further blocked by the box body paved with soundproof cotton, so that the noise transmitted to the working area outside the box body is further reduced.

[0034] The application has the following beneficial effects:

[0035] The application provides a 3D printing sanding device noise reduction device and method, the sound shield blocks most high-frequency noise generated by V-shaped groove vibration through sound wave reflection, energy conversion and absorption principle, and then reduces low-frequency noise that cannot be eliminated by the sound shield through an active noise reduction module, and finally, the noise is further reduced after being blocked by the box with soundproof cotton laid on the wall.

[0036] The semi-closed installation of the sound shield protects the cam mechanism to reduce the failure rate, avoids the temperature being too high in the sound shield, ensures the visibility of the internal structure of the sound shield, facilitates equipment maintenance and repair, and meanwhile, the maintenance cost of the sound shield is relatively low.

[0037] The active noise reduction module not only effectively reduces noise, but also alarms equipment failure, and improves safety. BRIEF DESCRIPTION OF DRAWINGS

[0038] The application will be further described below in combination with the drawings and specific embodiments,

[0039] ATTACHMENT Figure 1 is a structural schematic diagram of the 3D printing sanding device noise reduction device of the application Figure 1 ;

[0040] ATTACHMENT Figure 2 is a structural schematic diagram of the 3D printing sanding device noise reduction device of the application Figure 2 ;

[0041] ATTACHMENT Figure 3 is a structural schematic diagram of the 3D printing sanding device noise reduction device of the application Figure 1 ;

[0042] ATTACHMENT Figure 4 is a structural schematic diagram of the 3D printing sanding device noise reduction device of the application Figure 2 ;

[0043] ATTACHMENT Figure 5 is a connection structure diagram of the active noise reduction module involved in the application

[0044] ATTACHMENT Figure 6 is a structural schematic diagram of the active noise reduction module involved in the application

[0045] ATTACHMENT Figure 7 is a structural schematic diagram of the sound shield involved in the application

[0046] ATTACHMENT Figure 8 is a structural schematic diagram of the secondary loudspeaker involved in the application.

[0047] In the figure: 1, box; 2-3, sound shield; 21, upper clamping seat; 211, bolt hole; 22, protective layer; 23, sound absorption layer; 24, sound insulation layer; 25, damping layer; 26, sound shield wall; 27, lower clamping seat; 4, active noise reduction module; 41, primary microphone array; 411, microphone; 42, controller; 43-44, secondary loudspeaker; 431, loudspeaker body; 432, rotating member; 4321, fixed shaft; 4322, rotating block; 4323, rotating shaft; 433, loudspeaker base; 45-46, error microphone; 47, wire; 5, control cabinet; 6, sanding machine; 61-62, sanding machine support; 63, vibration motor; 64, sand storage tank; 641-642, sand storage tank end plate; 643-644, sand storage tank side wall; 645, sand storage tank cavity; 65, V-shaped groove; 66, transmission rod; 67, cam assembly; 7, sanding machine support. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0049] In the description of the present application, it should be understood that the angles or positional relationships indicated by the terms "upper side", "lower side", "upper end", "two ends", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the angles or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular angle, be constructed and operated at a particular angle, and therefore cannot be understood as limiting the present application.

[0050] In the present application, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection", "communication" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected; it can be mechanically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0051] Embodiment 1

[0052] Reference Figure 1 and 2 The present embodiment provides a 3D printing sanding machine noise reduction device, which comprises a sound shield 2, 3 and an active noise reduction module 4.

[0053] Referring to Figure 7 , the soundproof cover 2, 3 comprises a protective layer 22, a sound absorption layer 23, a sound insulation layer 24, a damping layer 25 and a soundproof cover wall 26 from inside to outside, forming a 5-layer arc-shaped structure soundproof cover to block the noise generated by the sanding machine 6, each layer is tightly attached and curved outwardly in an arc shape, which cooperates with the sanding machine to form a semi-closed structure.

[0054] The protective layer 22 plays a protective role on the inner wall of the soundproof cover 2, 3 to block the internal parts from splashing and protect the internal parts, which adopts a 30% large-diameter perforated steel plate with a thickness of 1mm. The sound absorption layer 23 is a porous structure, which reflects sound waves multiple times after entering, absorbs sound energy and converts it into heat energy, and plays a role in absorbing noise, which is made of glass wool with a thickness of 30mm. The sound insulation layer 24 adopts a sealed, shielded and soundproof structure to prevent sound waves from passing through and play a role in blocking noise, which is a PU adhesive sound insulation pad with a thickness of 5mm. The damping layer 25 reduces the energy output of the sound source vibration by absorbing, isolating and changing the sound wave propagation path to prevent the soundproof cover 2, 3 from resonating, which is made of asphalt damping material with a thickness of 6mm. The soundproof cover wall 26 is used to support and protect the structure of each layer of the soundproof cover 2, 3, which is made of S45 steel with a light material and a thickness of 2mm. The soundproof cover wall 26 is installed on the outermost layer and is easy to disassemble and clean.

[0055] Referring to Figure 3 and 4 The sanding machine 6 comprises a V-shaped groove 65, a transmission rod 66, a cam mechanism arranged on the transmission rod 66, and a vibration motor 63 connected to one end of the transmission rod 66, the cam mechanism comprises four cam assemblies uniformly connected to the transmission rod 66, the vibration motor 63 drives the cam assembly 67 to vibrate through the transmission rod 66, the cam assembly 67 is connected to one side of the V-shaped groove 65 to excite the V-shaped groove 65 to vibrate and generate noise.

[0056] The sanding machine 6 further comprises a sand storage groove 64, the sand storage groove 64 comprises two sand storage groove side walls 643, 644 arranged in the axial direction (the axial direction of the transmission rod 66), two sand storage groove end plates 641, 642 arranged between the two sand storage groove side walls 643, 644 and at the ends of the sand storage groove side walls 643, 644 respectively, and a sand storage groove cavity 645 surrounded by the sand storage groove end plates 641, 642 and the sand storage groove side walls 643, 644, which is used for storing sand during printing. The sand storage groove cavity 645 is connected to the upper side of the V-shaped groove 65, and the sand falls through the sand storage groove 645 and the V-shaped groove 65 in sequence.

[0057] The soundproof cover 2, 3 is respectively provided with an upper clamping seat 21 and a lower clamping seat 27 at two ends, and the soundproof cover 2, 3 is tightly attached between layers through the upper clamping seat 21 and the lower clamping seat 27. The upper clamping seat 21 is provided with a bolt hole 211, which is used for bolt connection of the soundproof cover 2, 3 on the sand storage tank side wall 633, 634. The soundproof cover 3 shields the surface connected with the V-shaped groove 65 of the cam mechanism, that is, the noise excitation surface, and the soundproof cover 2 mirrors the side opposite to the noise excitation surface, which is used for blocking the noise of the excitation surface.

[0058] The cross section of the soundproof cover 2, 3 is circular arc, which is curved outward and cooperates with the sand spreader 6 to form a semi-closed structure, that is, a semi-closed cavity, and the two ends of the cavity are open and communicated with the outside. On the one hand, the original cam mechanism is exposed to the outside, which is easy to malfunction after mixing sand for a long time. Therefore, the installation of the soundproof cover 2, 3 plays a role in protecting the cam mechanism and the transmission rod 66. On the other hand, since the printer generates heat during operation, the semi-closed structure of the soundproof cover 2, 3 not only effectively reduces noise but also ensures ventilation effect, avoids high temperature in the soundproof cover 2, 3, and ensures the visibility of the internal structure, which is convenient for equipment maintenance and repair.

[0059] Referring to Figure 2 , 5 and 6, the active noise reduction module 4 includes a controller 42, a primary microphone array 41 located in a noise area and an angle-adjustable secondary loudspeaker 43, 44, an error microphone 45, 46 located in a noise reduction area, the primary microphone array 41 receives the noise signal blocked by the soundproof cover 2, 3 and transmits it to the controller 42, the controller 42 analyzes and processes the noise signal blocked by the soundproof cover 2, 3 to control the secondary loudspeaker 43, 44 to emit sound waves with the same amplitude and opposite phase as the noise signal blocked by the soundproof cover 2, 3, and adjusts the sound waves emitted by the secondary loudspeaker 43, 44 according to the noise signal in the noise reduction area transmitted by the error microphone 45, 46 to the controller 42 as a feedback signal (residual noise signal).

[0060] The 3D printing sanding device 6 noise reduction device further comprises a box 1, the inner side walls and the inner side top wall of the box 1 are paved with sound insulation cotton, and the two ends of the sanding device 6 are fixed and accommodated in the box 1 through a sanding device support 7. The space in the box 1 is referred to as a noise area, and the space outside the box 1 is referred to as a noise reduction area or a working area. The primary microphone array 41 is connected to the inner wall above the middle part of the sanding device 6, the secondary loudspeakers 43 and 44 are connected to the upper part of the inner side wall opposite to the ends of the sanding device 6, the two secondary loudspeakers 43 and 44 are oppositely arranged, the error microphones 43 and 44 are arranged on the outer wall of the box 1, and the controller 42 is arranged outside the box 1. The primary microphone array 41, the secondary loudspeakers 43 and 44, the error microphones 45 and 46, and the controller 42 are connected through wires 47. The outer wall of the box 1 is further provided with a control cabinet 5, the controller 42 and the control cabinet 5 are connected together, and synchronous control of sanding and noise reduction of the 3D printer is conveniently realized.

[0061] The controller 42 comprises a control unit, a storage unit, a signal processing unit and a warning unit. The signal processing unit analyzes noise signals to determine the direction, amplitude and frequency of the noise source. According to the processing result of the signal processing unit, the control unit controls the secondary loudspeakers 43 and 44 to emit sound waves with the same amplitude and opposite phase as the noise of the noise source.

[0062] The storage unit is used for storing predetermined noise reduction schemes and fault noise signals. The predetermined noise reduction schemes include the rotation speed of the vibration motor 63, the type of printing sand, and the sound emission angle and sound waves emitted by the secondary loudspeakers 43 and 44 under the rotation speed. In use, the predetermined noise reduction schemes and the fault noise signals can be pre-stored in the storage unit, or the noise reduction schemes achieving the expected noise reduction effect during operation can be stored as the predetermined noise reduction schemes, or the fault noise signals encountered during operation can be stored for subsequent use.

[0063] The active noise reduction module 4 can adjust the sound emission angle and sound waves emitted by the secondary loudspeakers 43 and 44 in real time on site, i.e. in a field mode, or can call the noise reduction schemes pre-stored in the storage unit, i.e. in an automatic mode. In the automatic mode, when the rotation speed of the vibration motor 63 and the type of printing sand are consistent with the predetermined noise reduction schemes stored, the controller 42 automatically calls the stored predetermined noise reduction schemes, quickly adjusts the sound emission angle of the secondary loudspeakers 43 and 44, and emits corresponding sound waves.

[0064] In the process of working of the active noise reduction module, when the primary microphone array 41 receives the pre-stored fault noise signal, the early warning unit issues an alarm to remind the staff to check; if the noise reduction device of the 3D printing sand spreader 6 cannot achieve the expected noise reduction effect all the time, the early warning unit issues an alarm to remind the staff to check, and the controller 42 extracts the noise signal received by the primary microphone array 41 as the fault noise signal and stores it in the storage unit.

[0065] In use, the main noise frequency generated by the vibration of the V-shaped groove 65 is 60-2000Hz frequency, and the sound shield cover 2, 3 blocks most of the high-frequency noise generated by the vibration of the V-shaped groove 65 through sound wave reflection, absorption and other principles, effectively reduces the noise in the range of 300-2000Hz, and the active noise reduction module 4 effectively reduces the 60-300Hz low-frequency noise which the sound shield cover 2, 3 has poor noise reduction effect. After being blocked by the box 1 laid with sound insulation cotton, the noise transmitted to the outside of the box is further reduced.

[0066] wherein,

[0067] Referring to Figure 6 The primary microphone array 41 is composed of 9 microphones 411 arranged in three rows and three columns. The controller 42 evaluates the noise source position according to the geometric information of the microphone 411 distribution, the noise environment, and the time difference of the noise signal received by each microphone 411.

[0068] Referring to Figure 8 The secondary loudspeaker 43, 44 includes a loudspeaker body 431, a rotating member 432 connected with the loudspeaker body 431, and a loudspeaker base 433. The secondary loudspeaker 43, 44 is detachably connected to the inner side wall of the box 1 through the loudspeaker base 433, and the loudspeaker body 431 is transversely and vertically rotated through the rotating member 432, so as to finally realize the sound emitting angle of the secondary loudspeaker 43, 44.

[0069] The rotating member 432 includes a fixed shaft 4321 arranged on the loudspeaker base 433, a rotating block 4322 rotating around the fixed shaft 4321, and a rotating shaft 4323 arranged on the rotating block. The loudspeaker body 431 is connected with the outer end of the rotating shaft 4323. The rotating block 4322 rotates around the fixed shaft 4321 to realize the vertical rotation of the loudspeaker body 431, and the loudspeaker body 431 rotates around the rotating shaft 4323 to realize the transverse rotation of the loudspeaker body 431.

[0070] Simulation analysis of the noise reduction effect of the sound shield cover:

[0071] The noise reduction effect simulation analysis is carried out on the five-layer special structure soundproof cover 2, 3, the surface sound pressure level of the box 1 is reduced from 80dB(A) to about 40dB(A), the local maximum noise is about 60dB(A), and the average insertion loss of the sound pressure level measuring point around the sanding machine 6 is 12.5dB(A), 11dB(A), 15.8dB(A) and 13.5dB(A) respectively. In addition, the arc-shaped soundproof cover is more likely to receive noise wave reflection, and is more likely to realize sound absorption and sound insulation. The noise reduction effect simulation analysis is carried out on the "L" shaped soundproof cover, and the average insertion loss of the sound pressure level measuring point around the sanding machine 6 is 1.85dB(A), 6.61dB(A), 6.61dB(A) and 6.64dB(A) respectively, which is much smaller than the average insertion loss of the arc-shaped soundproof cover, i.e. 12.5dB(A), 11dB(A), 15.8dB(A) and 13.5dB(A), so the arc-shaped soundproof cover has better sound insulation effect.

[0072] Embodiment 2

[0073] The embodiment provides a 3D printing sanding machine noise reduction method, which is applied to the 3D printing sanding machine noise reduction device in embodiment 1, and the method comprises the following steps:

[0074] S1: installing the soundproof cover 2, 3 on both sides of the sanding machine 6, and installing the active noise reduction module 4 on the box 1.

[0075] S2: after the printer is started, part of the noise generated by the sanding machine 6 is blocked by the soundproof cover 2, 3.

[0076] S3: the primary microphone array 41 receives the noise signal of the noise source blocked in step S1 and transmits it to the controller 42.

[0077] S4: the controller 42 performs filtering calculation and signal processing on the noise signal received by the primary microphone array, judges the direction, amplitude and frequency of the noise source.

[0078] S5: according to the direction, amplitude and frequency of the noise source in step S4, the controller 42 controls the secondary loudspeaker 43, 44 to emit sound waves with the same noise propagation path as the noise source and the same amplitude and opposite phase as the noise signal, and adjusts the secondary loudspeaker 43, 44 to the appropriate sound emitting angle through the rotating member 432, so as to realize noise reduction.

[0079] S6: the controller 42 receives the residual noise signal returned by the error microphone 45, 46 in real time, analyzes the noise information of the residual noise signal, and continuously adjusts the sound emitting angle and sound wave characteristics of the secondary loudspeaker 43, 44 until the optimal noise reduction effect is achieved.

[0080] S7: The optimal noise reduction scheme at a certain rotating speed is set as a predetermined noise reduction scheme stored in the controller 42, including the rotating speed of the vibration motor 63, the type of printing sand, and the sound emitting angle and sound wave emitted by the secondary loudspeakers 43 and 44 at the rotating speed. When the rotating speed of the vibration motor 63 and the type of printing sand are consistent with the stored noise reduction scheme during the operation of the printer, the controller 42 automatically calls the stored predetermined noise reduction scheme, quickly adjusts the sound emitting angle of the secondary loudspeakers 43 and 44, and emits corresponding sound waves. The noise signals of known equipment failures are stored in the controller 42. When the primary microphone array 41 receives the failure noise signal, the controller 42 issues an alarm to remind the staff to check.

[0081] S8: The residual noise after the active noise reduction module 4 in step S6 reduces noise is further reduced after being blocked by the box 1 paved with sound insulation cotton and transmitted to the working area outside the box 1.

[0082] It should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some technical features thereof, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A 3D printing sand spreader noise reduction device, characterized in that: The device comprises an active noise reduction module and soundproof covers on both sides of the sanding machine. The soundproof cover comprises, from inside to outside, a protective layer for blocking, a sound absorption layer and a sound insulation layer for reducing noise, a damping layer for preventing resonance of the soundproof cover, and a soundproof cover wall for blocking noise generated by the sanding machine. The 3D printing sanding machine noise reduction device further comprises a box with sound insulation cotton laid on the inner wall surface, and the sanding machine is accommodated in the box. The sanding machine comprises a V-shaped groove, a transmission rod, a cam mechanism arranged on the transmission rod, and a vibration motor connected to one end of the transmission rod. The active noise reduction module comprises a controller, a primary microphone array, an error microphone, and an angle-adjustable secondary loudspeaker. The primary microphone array is arranged on the inner wall above the middle part of the sanding machine to receive the noise signal blocked by the soundproof cover and transmit it to the controller. The secondary loudspeaker is connected to the inner wall opposite to the end of the sanding machine. The controller filters, calculates, and processes the noise signal to determine the noise source direction, amplitude, and frequency, and then controls the secondary loudspeaker to emit sound waves with the same amplitude and opposite phase as the blocked noise. The controller comprises a storage unit for storing a predetermined noise reduction scheme and a fault noise signal. The predetermined noise reduction scheme includes the vibration motor speed, the type of printing sand, and the sound emission angle and sound wave of the secondary loudspeaker at the speed. The warning unit issues an alarm when the primary microphone array receives a fault noise signal or the device does not achieve the expected noise reduction effect.

2. The 3D printing sanding machine noise reduction device of claim 1 further comprises a sand storage tank. The sand storage tank comprises an axially arranged sand storage tank side wall and a sand storage tank end plate at the end of the sand storage tank side wall. The sand storage tank side wall and the sand storage tank end plate cooperate to form a sand storage tank cavity. The sand storage tank cavity is connected to the V-shaped groove. The sanding machine beam is arranged on both sides of the sanding machine. The upper and lower clamping seats are arranged at the ends of the soundproof cover to tightly fit the layers of the soundproof cover. The soundproof cover is curved outwardly in an arc shape and forms a semi-closed structure with the sanding machine.

3. The 3D printing sanding machine noise reduction device of claim 1 further comprises a control unit and a signal processing unit. The signal processing unit analyzes the blocked noise signal to determine the noise source direction, amplitude and frequency, and the control unit controls the secondary speaker to emit sound waves with the same amplitude and opposite phase of the blocked noise signal according to the processing result of the signal processing unit; The active noise reduction module includes adjusting the sound emitting angle of the secondary speaker in real time on site, i.e. the field mode, and calling the pre-stored predetermined noise reduction scheme in the storage unit, i.e. the automatic mode; in the automatic mode, when the vibration motor speed and the type of printing sand of the printer are consistent with the vibration motor speed and the type of printing sand in the stored noise reduction scheme, the controller automatically calls the stored predetermined noise reduction scheme, quickly adjusts the sound emitting angle of the secondary speaker, and emits the sound waves in the corresponding predetermined noise reduction scheme.

4. The noise reduction device of the 3D printing sand spreader according to claim 1 or 3, characterized in that: The primary microphone array includes microphones distributed in multiple rows and columns, and the controller evaluates the noise source position according to the geometric information of the microphone distribution, the noise environment and the time difference of the noise signals received by each microphone.

5. The noise reduction device of the 3D printing sand spreader according to claim 1, characterized in that: The controller is arranged outside the box.

6. The noise reduction device of the 3D printing sand spreader according to claim 5, characterized in that: The secondary speaker includes a speaker body, a rotating member connected to the speaker body, and a speaker base, the secondary speaker is detachably connected to the inner side wall of the box through the speaker base, and the speaker body is transversely and vertically rotated through the rotating member.

7. The noise reduction device of the 3D printing sand spreader according to claim 6, characterized in that: The rotating member includes a fixed shaft arranged on the speaker base, a rotating block rotating around the fixed shaft, and a rotating shaft arranged on the rotating block, the speaker body is connected to the outer end of the rotating shaft, the speaker body is vertically rotated by rotating the rotating block around the fixed shaft, and the speaker body is transversely rotated by rotating the rotating shaft.

8. The noise reduction device of the 3D printing sand spreader according to claim 1, characterized in that: The protective layer is a steel plate, the sound absorption layer is a porous structure made of glass wool, the sound insulation layer is a PU adhesive sound insulation pad, the damping layer is made of asphalt damping material, and the sound insulation cover wall is made of S45 steel.

9. A 3D printing sand spreader noise reduction method, applied to the 3D printing sand spreader noise reduction device of any one of claims 1-8, characterized in that, Specifically comprising the following steps: S1: installing a sound insulation cover on both sides of the sand spreader and installing an active noise reduction module on the box; S2: after the printer is started, part of the noise generated by the sand spreader is blocked by the sound insulation cover; S3: the primary microphone array receives the noise signal blocked in step S2 and transmits it to the controller; S4: the controller filters and calculates the noise signal received by the primary microphone array, processes the signal, determines the noise source direction, amplitude and frequency; S5: according to the noise source direction, amplitude and frequency in step S4, the controller controls the secondary speaker to emit sound waves with the same amplitude and opposite phase of the noise signal propagation path of the noise source, and adjusts the secondary speaker to the appropriate sound emitting angle through the rotating member to achieve noise reduction. S6: The controller receives the feedback signal returned by the error microphone in real time, that is, the residual noise signal, analyzes the residual noise signal, and continuously adjusts the sound angle, sound phase and amplitude of the secondary loudspeaker until the optimal noise reduction effect is achieved; S7: The noise reduction scheme under a specific speed is set as a predetermined noise reduction scheme stored in the controller, including the vibration motor speed, the printing sand type, and the sound angle and sound wave emitted by the secondary loudspeaker under the speed. When the vibration motor speed and the printing sand type are consistent with the vibration motor speed and the printing sand type in the stored noise reduction scheme during the operation of the printer, the controller automatically calls the stored predetermined noise reduction scheme, quickly adjusts the sound angle of the secondary loudspeaker, and emits the corresponding sound wave; the fault noise signal of the 3D printing sand laying device is stored in the controller, and when the primary microphone array receives the fault noise signal or cannot achieve the expected noise reduction effect, the controller issues an alarm to remind the worker to check; S8: The noise after the active noise reduction module is further blocked by the box body paved with sound insulation cotton, so that the noise transmitted to the working area outside the box body is further reduced.

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