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Designing and manufacturing a machine for removing rusted objects using ultrasonic waves


ABSTRACT
Research, design, and implementation of an ultrasonic cleaning machine to remove rust from materials in the industrial setting Most industries today use a lot of metal materials in their operations, which can cost the factories billions of dollars. Despite several efforts to recycle and reuse metal materials, in today's industrial production, there is a growing need for flawless cleaning methods: the current cleaning methods have drawbacks, such as the inability of mechanical methods to clean sandpaper effectively and the inability of chemical methods to remove stubborn dirt without damaging products.
Consequently, there is a need for an appropriate, quick, and hygienic cleaning method that also satisfies technical and financial requirements.
In order to tackle this issue, our group has researched the theory of ultrasonic waves and how to produce them. We have effectively integrated ultrasonic technology with the notion of recycling materials used in factories by proposing the idea of using ultrasonic to clean the rusty materials in order to achieve superior cleaning results.
Our basic model consists of an Arduino Uno microprocessor and a servo motor to control the machine, providing comparable cleaning functions to current market products while addressing some of their shortcomings. With this innovative approach, we hope to revolutionize the industry with reusable materials, offering a dependable way to thoroughly clean complex components and guarantee a flawless outcome without sacrificing safety or efficacy.
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TABLE OF CONTENTS
GRADUATION PROJECT ASSIGNMENT ........................................................................ i ADVISOR’S EVALUATION SHEET ..................................................................................ii PRE-DEFENSE EVALUATION SHEET ............................................................................iii EVALUATION SHEET OF .................................................................................................. iv DEFENSE COMMITTEE MEMBER ................................................................................ iv ACKNOWLEDGEMENT ..................................................................................................... v ABSTRACT ...........................................................................................................................vi TABLE OF CONTENTS .....................................................................................................vii LIST OF FIGURES ............................................................................................................... xi LIST OF TABLES ............................................................................................................... xiv CHAPTER 1: OVERVIEW ................................................................................................... 1
1.1. Introduction ................................................................................................................... 1 1.2. Target ............................................................................................................................. 1 1.3. Research content............................................................................................................ 1 1.4. Limitation ...................................................................................................................... 2 1.5. Research Topics And Range .......................................................................................... 2
1.5.1. Research Topics ...................................................................................................... 2 1.5.2. Research Scope....................................................................................................... 2 1.5.3. Research Methods .................................................................................................. 2 1.5.4. Outline Of The Graduation Thesis ......................................................................... 3
CHAPTER 2. THEORETICAL BASIS ............................................................................... 4
2.1. Ultrasonic Wave Theory Overview ............................................................................... 4 2.2. The Nature Of Sound Waves ......................................................................................... 4 2.3. Ultrasonic Wave Properties ........................................................................................... 4 2.4. Ultrasound Wave Parameters......................................................................................... 5
2.4.1. Frequency ............................................................................................................... 7 2.4.2. Wavelength ............................................................................................................. 7
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2.4.3. Velocity ................................................................................................................... 7
2.4.4. Absorption Of Ultrasonic Waves By The Transmitting Medium ........................... 7 2.5. Cleaning Technology ..................................................................................................... 7 2.5.1. Traditional Cleaning Technology ........................................................................... 7 2.5.2. Using Ultrasonic Cleaning Technology For Cleaning............................................ 8 2.5.3. Ultrasonic Cleaning Technology Cleaning Principle ............................................. 8 2.5.4. Cleaning Process Using Ultrasonic Cleaning Technology ..................................... 9 2.5.5. Advantages Of Ultrasonic Cleaning Technology ................................................. 12 2.6. Factors Influencing The Ultrasonic Cleaning Technology's Cleaning Procedure....... 12 2.6.1. Frequency And Bubble Size Relationship............................................................ 12 2.6.2. Chemical Effects................................................................................................... 14 2.6.3. Effect Of Temperature .......................................................................................... 16 2.6.4. Time Required For Cleaning ................................................................................ 17 2.6.5. Power And Tank Volume Of Ultrasonic ............................................................... 17 2.6.6. Considerations When Use A Cleaning Solution And Ultrasonic Cleaning .......... 17 2.7. Functions And Categorization Of Transducers: .......................................................... 18 2.7.1. Transmitting Transducer ....................................................................................... 18 2.7.2. Receiving Transducer ........................................................................................... 18 2.7.3. Piezoelectric Transducer.......................................................................................18 2.7.4. Magnetostriction...................................................................................................22 2.8. Survey The Types Of Ultrasonic Cleaners Available On The Market ........................ 22 2.9. Introduction Of Web Server......................................................................................... 25 2.9.1 Introduction Of Website ........................................................................................ 25 2.9.2. Web Programming Language ............................................................................... 25 2.9.3. SQL Database ....................................................................................................... 26 2.10. Introduction Of Bootstrap.......................................................................................... 28 2.10.1. What Is Bootstrap? ............................................................................................. 28 2.10.2. Bootstrap Components And Their Functionalities ............................................. 28 2.10.3. The Structure And Features Of Bootstrap .......................................................... 28
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2.10.4. Advantages And Disadvantages Of Bootstrap.................................................... 29
2.11. Introduction To AJAX Technology............................................................................ 29
2.11.1. Introduction of AJAX ......................................................................................... 29
2.11.2. How AJAX Works .............................................................................................. 29
2.11.3. Advantages And Disadvantages Of AJAX ......................................................... 30
CHAPTER 3. DESIGN OF MECHANICAL SYSTEM ................................................... 32
3.1. Introduction ................................................................................................................. 32
3.2. Machine Structure Requirements ................................................................................ 32
3.3. Analysis And Choice Of Components ......................................................................... 32
S3.3.1. Guidance Mechanism For The X Axis ............................................................... 32
3.3.2. Guidance Mechanism for the Z Axis.................................................................... 46
3.3.3. Choose A Tank ...................................................................................................... 47
3.3.4. Calculating Load-Bearing Capacity ..................................................................... 48
CHAPTER 4. DESIGN OF ELECTRICAL AND CONTROL SYSTEM ...................... 54
4.1. Introduction ................................................................................................................. 54
4.2. Control System ............................................................................................................ 54
4.2.1. Motor Control ....................................................................................................... 56
4.2.2. Communication Between Control Circuit And Computer ................................... 56
4.2.3. Operating Process ................................................................................................. 58
4.3. Electrical System ......................................................................................................... 59
4.3.1. Overview of the electrical system ........................................................................ 59
4.3.2. Electrical Safety.................................................................................................... 60
4.3.3. Electrical Devices In Use ..................................................................................... 60
4.4. Developing A Temperature Control Algorithm ........................................................... 82
4.4.1. Overview Of The Temperature Control Unit ....................................................... 82
4.4.2. Overview Of PID Control .................................................................................... 83
4.4.3. Operating Principle............................................................................................... 84
4.4.4. PID Controller ...................................................................................................... 84
CHAPTER 5: BUILDING A USER INTERFACE AND INTERACTIVE WEB INTERFACE ......................................................................................................................... 93
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5.1. Introduction ................................................................................................................. 93
5.2. User Interface .............................................................................................................. 93
5.2.1. Introduction To Python Programming Language ................................................. 93
5.2.2. Introducing An Overview Of The User Interface ................................................. 93
5.3. Web Interface ............................................................................................................... 96
5.3.1. Introduction to IoT ............................................................................................... 96
5.3.2. Designing A Control Website ............................................................................... 97
5.3.3. Overview Of Monitoring On The Webserver ....................................................... 98
CHAPTER 6. IMPLEMENTATION, EXPERIMENT RESULTS/ FINDINGS AND ANALYSIS .......................................................................................................................... 102
6.1. Implementation..........................................................................................................102 6.2. Set Objective Requirements ...................................................................................... 105 6.2.1 Qualitative Statements.........................................................................................105 6.2.2. Correlation Between Needs And Metrics ........................................................... 105 6.2.3. Experiments ........................................................................................................ 106 6.3. Analysis ..................................................................................................................... 110 CHAPTER 7. CONCLUSION AND RECOMMENDATIONS ..................................... 112 7.1. Lessons Learned ........................................................................................................ 112 7.2. Future Development .................................................................................................. 112 REFERENCES ................................................................................................................... 113
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LIST OF FIGURES
Figure 1. 1. Industrial Ultrasonic Washing Machine ................................................................ 1
Figure 2. 1. Types Of Balance .................................................................................................. 4 Figure 2. 2. Waveform Representation ..................................................................................... 6 Figure 2. 3. Compression And Rarefaction In A Longitudinal Wave....................................... 6 Figure 2. 4. Cleaning Process 1 ................................................................................................ 9 Figure 2. 5. Cleaning Process 2 .............................................................................................. 10 Figure 2. 6. Cleaning Process 3 .............................................................................................. 10 Figure 2. 7. Cleaning Process 4 .............................................................................................. 11 Figure 2. 8. Cleaning Process 5 .............................................................................................. 11 Figure 2. 9. Frequency And Bubble Size Relationship .......................................................... 13 Figure 2. 10. Direct Piezoelectric Effect (A) Tension Force (B) Compressive Force............ 19 Figure 2. 11. Inverse Piezoelectric Effect............................................................................... 21 Figure 2. 12. How An Ultrasonic Transducer Is Constructed ................................................ 22 Figure 2. 13. Rama Ultrasonic Cleaner .................................................................................. 23 Figure 2. 14. Jeken Ultrasonic Cleaner .................................................................................. 24
Figure 3. 1. Lead Screw And Nut ........................................................................................... 33 Figure 3. 2. CNC Machine Lead Screw ................................................................................. 34 Figure 3. 3. Lead Screw For Lifting And Lowering............................................................... 34 Figure 3. 4. Integral-Structure Actuator ................................................................................. 35 Figure 3. 5. BK Bearing ......................................................................................................... 40 Figure 3. 6. BF Bearing .......................................................................................................... 40 Figure 3. 7. SGMAV-01ADA21 AC Servo ............................................................................ 44 Figure 3. 8. Servo Driver Yaskawa SGDV-R90A01A ........................................................... 45 Figure 3. 9. Cylinder TD-16-175-SE-1 .................................................................................. 46 Figure 3. 10. Arwa AW-2040 2.0HP Air Compressor ............................................................ 47 Figure 3. 11. Design A Sink With Solidworks........................................................................ 48
Figure 4. 1. Block control diagram......................................................................................... 54 Figure 4. 2. Electrical system diagram ................................................................................... 55 Figure 4. 3. Servo motor control diagram .............................................................................. 56 Figure 4. 4. The connection and communication diagram ..................................................... 57 Figure 4. 5. Operating Flowchart Diagram ............................................................................ 58 Figure 4. 6. Wiring diagram in electrical system ................................................................... 59
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Figure 4. 7. Arduino Uno........................................................................................................ 60 Figure 4. 8. ESP8266 .............................................................................................................. 62 Figure 4. 9. Ultrasonic Distance Sensor ................................................................................. 63 Figure 4. 10. K Type Thermocouple (MAX6675).................................................................. 64 Figure 4. 11. Settings for The MAX6675 ............................................................................... 66 Figure 4. 12. MAX6675 Pinout .............................................................................................. 66 Figure 4. 13. Connecting MAX6675 to Arduino.................................................................... 66 Figure 4. 14. Connect The Microcontroller And MAX6675.................................................. 67 Figure 4. 15. SPI Protocol of MAX6675................................................................................ 67 Figure 4. 16. Zero Point Detection Circuit On Proteus .......................................................... 68 Figure 4. 17. PC817 Diagram ................................................................................................. 69 Figure 4. 18. Result on Proteus of Zero Point Detection Circuit ........................................... 70 Figure 4. 19. Zero Detection Circuit PCB .............................................................................. 70 Figure 4. 20. Triac Trigger Circuit On Proteus....................................................................... 71 Figure 4. 21. The Relationship Between The Triac Firing Angle And Time ......................... 71 Figure 4. 22. The Length Of An Alternating Current (AC) Voltage Cycle ............................ 72 Figure 4. 23. MOC3021 Pinout .............................................................................................. 72 Figure 4. 24. Triac BTA16 - 600B Pinout .............................................................................. 73 Figure 4. 25. Heating Resistor ................................................................................................ 74 Figure 4. 26. Ultrasonic Wave Generator Circuit ................................................................... 75 Figure 4. 27. Ultrasonic Transducer ....................................................................................... 77 Figure 4. 28. Arranging Ultrasonic Transducers .................................................................... 78 Figure 4. 29. Intersecting Zone Of Ultrasonic Waves In Tank ............................................... 78 Figure 4. 30. An Explanation Of Wave Interference's Causes ............................................... 79 Figure 4. 31. An Explanation Of How L And Y Are Related ................................................. 80 Figure 4. 32. Water Pump ....................................................................................................... 81 Figure 4. 33. Diagram Of Closed-Loop PID Control.............................................................83 Figure 4. 34. Diagram When Using Some Methods .............................................................. 84 Figure 4. 35. PID Diagram ..................................................................................................... 85 Figure 4. 36. System Simulation Block Diagram................................................................... 86 Figure 4. 37. PID Block.......................................................................................................... 87 Figure 4. 38. System Block .................................................................................................... 87 Figure 4. 39. The Temperature Graph Of The Object Over Time .......................................... 88 Figure 4. 40. Comparing The Methods With Each Other....................................................... 90 Figure 4. 41. PI Method.......................................................................................................... 91 Figure 4. 42. Running PID In Reality With Setpoint 50oC .................................................... 91 Figure 4. 43. Running PID In Reality With Setpoint 60oC .................................................... 92
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Figure 5. 1. User Interface Block Diagram ............................................................................ 94 Figure 5. 2. Realistic User Interface ....................................................................................... 94 Figure 5. 3. Connect To Com Port .......................................................................................... 95 Figure 5. 4. Control Temperature And Water Level Via Web ................................................ 95 Figure 5. 5. Results Are Exported As Graphs......................................................................... 96 Figure 5. 6. Controller Design Diagram Via Web .................................................................. 97 Figure 5. 7. User Management Panel ..................................................................................... 99 Figure 5. 8. Database Properties ............................................................................................. 99 Figure 5. 9. Account Login Interface.................................................................................... 100 Figure 5. 10. Display Data.................................................................................................... 100 Figure 5. 11. Export Data To Excel ...................................................................................... 101 Figure 5. 12. Data Is Exported To Excel .............................................................................. 101
Figure 6. 1. Completed System Overview............................................................................ 102 Figure 6. 2. Completed System Top View ............................................................................ 102 Figure 6. 3. Servo System And Automatic Arm ................................................................... 103 Figure 6. 4. Making PCB Printed Circuits ........................................................................... 103 Figure 6. 5. Compeleted Zero Detection Circuit .................................................................. 104 Figure 6. 6. Completed Electrical Cabinet ........................................................................... 104 Figure 6. 7. Transducer Placement ....................................................................................... 105
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LIST OF TABLES
Table 2. 1. Several typical metal cleaning solutions. ............................................................. 15
Table 3. 1, Input Specifications Of Roller Screw ................................................................... 36 Table 3. 2. Working Condition Of Step Roller Screw ............................................................ 37 Table 3. 3. Load Factor Of Step Roller Screw ....................................................................... 39 Table 3. 4. Input Parameters ................................................................................................... 41 Table 3. 5. Type Of Servo Motor ............................................................................................ 41 Table 3. 6. Input Parameter Of AC Servo Motor.................................................................... 42 Table 3. 7. Specifications Of SGMAV-01ADA21 AC Servo ................................................. 45 Table 3. 8. Specifications Of Servo Driver Yaskawa SGDV-R90A01A ................................ 45 Table 3. 9. Specification Of Cylinder TD-16-175-SE-1......................................................... 46 Table 3. 10. Specifications Of Arwa AW-2040 2.0HP Air Compressor ................................. 47 Table 3. 11. Material Properties Table .................................................................................... 49 Table 3. 12. Properties Table Of Whole Automatic Arm....................................................... 50 Table 3. 13. Von Mises Stress ................................................................................................. 51 Table 3. 14. Resultant Displacement ...................................................................................... 52 Table 3. 15. : Equivalent Strain .............................................................................................. 52
Table 4. 1. Specifications of Arduino Uno ............................................................................. 61 Table 4. 2. Specifications of Ultrasonic Distance Sensor.......................................................63 Table 4. 3. Advantages And Disadvantages Of K Type Thermalcouple ................................ 64 Table 4. 4. Specifications of Thermocouple K Type .............................................................. 65 Table 4. 5. Specifications of MAX6675 Converter Module .................................................. 65 Table 4. 6. Specifications of PC817 ....................................................................................... 69 Table 4. 7. Specifications of MOC3021 ................................................................................. 72 Table 4. 8. The Specifications Of The Heating Resistor ........................................................ 75 Table 4. 9. Specifications of Ultrasonic Cleaning Circuit ...................................................... 76 Table 4. 10. Specifications of Ultrasonic Transducer ............................................................. 77 Table 4. 11. Specifications of Water Pump............................................................................. 82 Table 4. 12. Ziegler-Nichols 1 ................................................................................................ 89 Table 4. 13. Cohen-Coon ........................................................................................................ 89 Table 4. 14. Haalman .............................................................................................................. 89
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Table 6. 1. List of Metrics..................................................................................................... 106 Table 6. 2. Correlation Between Needs And Metrics ........................................................... 106 Table 6. 3. Compare Between Design Value And Actual Value ........................................... 107 Table 6. 4. Temperature Affects The Outcome ..................................................................... 108 Table 6. 5. Solven Affects The Outcome .............................................................................. 109
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CHAPTER 1: OVERVIEW
1.1. Introduction
Today, industrial production is making great strides, along with the need for technical means to maintain systems. During the maintenance process, one of the most important parts is cleaning equipment and machines that are rusted or have impurities stuck to them...
Traditional cleaning technologies (manual cleaning) no longer meet the new requirements, such as cleaning equipment with complex structures, many small nooks and crannies, which can scratch the pestle. machinery and equipment due to unwanted mechanical impacts. Therefore, the ultrasonic cleaner was born to overcome the above disadvantages.
Figure 1. 1. Industrial Ultrasonic Washing Machine
1.2. Target
Using the Arduino Uno microcontroller to control the power circuit system, calculate the appropriate power for the rusted object to be cleaned.
1.3. Research content
Survey of ultrasonic cleaners available on the market.
Summary of theory about ultrasonic washing machines, components related to washing machines.
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Choose a power circuit and pulse generator design option that is consistent with your abilities and theoretical knowledge learned.
Select the frequency appropriate to design needs and the impact of frequency on cleaning ability.
1.4. Limitation
Research and manufacturing washing machine capacity of 36 liters, using ultrasonic wave generator with frequency 40kHz , power of 240 Watt.
Control the blocks using Arduino Uno microcontroller.
The control system allows the user to control and monitor the working system on webserver.
1.5. Research Topics And Range
1.5.1. Research Topics
Examining the various kinds of rusted materials that are appropriate and can effectively enhance the cleaning power of the machine.
Sstudying the composition, principles of operation, and synthesis of theories related to cleaning machines that employ ultrasonic waves.
Designing a power circuit that is in line with the machine's capabilities and the theoretical knowledge that has been acquired.
Selecting a frequency that fits the design specifications and comprehending how frequency affects cleaning efficacy.
1.5.2. Research Scope
The sandpaper cleaning machine has a capacity of 8–10 liters and uses an ultrasonic wave generator operating at a frequency of 40 KHz with a power capacity of 60W.
The control system incorporates the use of an Arduino Uno microcontroller, enabling functionalities such as timer display and countdown, temperature display and control, as well as servo motor control along the X-axis.
Information gathered from scientific research conducted both domestically and internationally, examining previously published works in various scientific journals and references from documents, articles, and textbooks.
1.5.3. Research Methods
Researching methods from experiment and practice.
Gathering information from books, scholarly publications, journals, and documents online.
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Conducting surveys, interviews, observations, and secondary data analysis.
1.5.4. Outline Of The Graduation Thesis
Chapter 1: Overview
Chapter 2: Theoretical Basis
Chapter 3: Design Of Mechanical System
Chapter 4: Design Of Electrical And Control System
Chapter 5: Building A User Interface And Interactive Web Interface Chapter 6: Implementation, Experiment Results/ Findings And Analysis Chapter 7: Conclusion And Recommendations
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CHAPTER 2. THEORETICAL BASIS
2.1. Ultrasonic Wave Theory Overview
Ultrasound waves are also a mechanical wave and have basic properties through parameters such as frequency, wavelength...
2.2. The Nature Of Sound Waves
Elastic media (gas, liquid or solid) can be considered as continuous media consisting of closely interconnected particles. Normally, each element has a stable equilibrium position.
Figure 2. 1. Types Of Balance
If a force is applied to a certain element A inside this environment, it will leave its stable equilibrium position. Due to the interaction created by the connections with neighboring elements, on the one hand the element is pulled to the equilibrium position, on the other hand it is also affected by the impact force so the element will move back and forth around equilibrium position, which means that the element performs movement in the form of vibrations. This phenomenon continues to occur with other elements of the environment. Mechanical oscillations that are repetitive in nature and propagate in an elastic medium are called elastic waves or mechanical waves. In other words, a wave is a physical phenomenon in which energy is transmitted under the vibrational pattern of material elements of the wave medium.
2.3. Ultrasonic Wave Properties
Sound waves are vibrations of particles of solids, liquids and gases, which are elastic substances. In other words, sound waves are elastic waves propagating in an elastic medium,
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which means that all elastic objects can propagate sound waves. Depending on the frequency range, elastic waves are divided into the following regions:
The infrasonic region has a frequency from 1Hz to 20Hz The acoustic region has a frequency from 20Hz to 20kHz
The ultrasonic region has a frequency from 20kHz to 100MHz The ultrasonic region has a frequency > 100MHz
Although it has the same nature as an elastic wave, Due to different frequencies, they have different ap
Characteristics:
Ultrasonic waves carry greater energy than sound waves (for example, with the same amplitude of vibration, the wave energy at a frequency of 1MHz is 106 times greater than the wave energy at a frequency of 1kHz).
In the same wave transmission environment , ultrasonic waves have a short wavelength so they are highly directional, the wave energy travels in a certain direction. Taking advantage of this property, one can create focusing systems to concentrate large amounts of energy over a large area, narrow area.
In the ultrasonic wave range under certain conditions, wave cavitation occurs in liquids. This property is widely used in industry and civil use.
Doppler effect
2.4. Ultrasound Wave Parameters
The following diagram is a representation of a wave, which is a set of compression and expansion that vary in a sinusoidal order, with the peak representing the highest pressure and the bottom representing the lowest pressure.
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Figure 2. 2. Waveform Representation
Figure 2. 3. Compression And Rarefaction In A Longitudinal Wave
Characteristic quantities of waves include:
The period T=(s) is the time during which the wave performs one compression and one expansion.
Frequency f=(Hz) is the number of cycles performed in 1 second.
The propagation speed of a sound wave is the distance the sound wave travels after a unit of time.
Wavelength (μ): is the distance the wave travels after a period of time equal to 1 cycle ( = . = /).
In the figure, we see that wavelength is the distance between two adjacent peaks or troughs.
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2.4.1. Frequency
The frequency of a mechanical wave is also the oscillation frequency of the atoms of the medium in which the wave propagates. Frequency represents the number of cycles per second. The symbol for frequency is f, the unit is Hertz (Hz).
2.4.2. Wavelength
Wavelength is the distance a wave travels in a period of time T. Atoms separated by a distance will have the same vibrational state, that is, they will oscillate in the same phase when the wave passes through the medium.
2.4.3. Velocity
The rate at which energy is transferred between two points in the medium by the motion of the wave is called the wave velocity v.
2.4.4. Absorption Of Ultrasonic Waves By The Transmitting Medium
During the process of wave propagation in the medium, the wave intensity is gradually attenuated due to absorption by the medium and scattering of the wave. Energy loss depends on factors:
- Thermal conductivity, friction coefficient, heterogeneity of the environment.
- Frequency of the wave.
2.5. Cleaning Technology
2.5.1. Traditional Cleaning Technology
Cleaning is a problem that we all regularly face every day. In a more general sense, it is the cleaning of unnecessary and troublesome materials from the locations of equipment and parts that need cleaning.
Cleaning can be done in many ways. One of the most common traditional manual methods is to soak the device in a solution. This method is a combination of chemical action and mechanical action. The traditional method is mainly to use a brush to clean parts with simple structures, used for flat, smooth surfaces, not in nooks and crannies or places that are difficult to brush directly.
Advantages:
• The washing process is quick, simple, and does not require high technology. • Cheap
Disadvantages:
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• Cannot wash devices with complex structures, narrow gaps, and small nooks and crannies inside the device.
• Causes scratches on the surface by using a brush or broom.
• Deformation of surface and structure causing breakage of small, thin parts of the device.
2.5.2. Using Ultrasonic Cleaning Technology For Cleaning
Nowadays, industrial production is becoming more and more modern, production lines are being created to ensure the production of millions of products of the same type in a year. This reality requires very high quality, size uniformity, and repeatability to ensure easy assembly, less time and effort, and lower product costs. To achieve that, technological lines are often equipped with many ultrasonic cleaning devices in different stages. Make sure to "absolutely" clean the surface of the product before moving on to another processing step on that product. Ultrasonic cleaning technology is especially needed in the manufacturing industry of electronic circuit boards with high component density, in equipment for manufacturing metal mechanical parts with nooks and crannies in shape, many holes but , must have high cleanliness, hardness, and accuracy. Ultrasonic cleaning technology helps us handle dirt on the surface of the above details before entering the coating and surface polishing process.
2.5.3. Ultrasonic Cleaning Technology Cleaning Principle
Ultrasound waves are waves with frequencies greater than 18kHz, at this frequency humans cannot hear it.
In ultrasonic cleaners, the wave frequency is usually in the range of 20kHz - 200kHz. Ultrasonic waves used in ultrasonic washing machines applied to production lines and cleaning of medical instruments have high frequencies from 10kHz - 50kHz. Ultrasonic cleaners using frequencies higher than 50kHz are used to wash optical instruments, biological and industrial filters, and dental cleaning machines in hospitals.
Ultrasonic waves in ultrasonic cleaners are mechanical waves and they have full physical properties such as transmission method, reflection, wave interference, etc., in different transmission environments.
When a mechanical wave is created in air or in a liquid, under the effect of pressure, a quantity of matter is compressed to form waves, this wave is moved towards the lower pressure side and propagates. transmitted in different directions, but the strongest is still the direct direction of the thrust. This wave beam contains countless higher frequency beams, so countless small beams often called bubbles appear in the beam. The size of these bubbles develops quite diversely, usually depending on the frequency of the ultrasound wave. The higher the ultrasound wave, the smaller the bubble size.
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These bubbles move one after another in the liquid medium until they hit the surface of an obstacle in the wave path. Under the compression force of the waves, the bubbles burst, creating explosions, shooting liquid particles directly into the surface of the object. These bombardments separate the layers of dirt and dust covering the surface of the liquid and pull them away from the object when negative pressure appears in the liquid near the surface of the object.
2.5.4. Cleaning Process Using Ultrasonic Cleaning Technology
When power is applied to the ultrasonic sensor, this sensor creates mechanical vibrations on its surface with a frequency greater than 20,000 vibrations/second. This mechanical wave is transmitted directly into the stainless steel of the ultrasonic cleaning tank and creates high- frequency shocks in the liquid of the ultrasonic cleaning tank. Under the impact of high- frequency mechanical shocks, countless small-sized bubbles are created in a short time and propagate in all directions within the liquid, and this movement fully complies with the laws of waves. muscle in dragon fluid. The bubbles move forward and hit the surface of the object to be washed, creating a mechanical bombardment of dirt on the surface. Under the impact of this bombardment force, the dust is separated from the surface and easily dissolves into the cleaning solvent thanks to the effect of chemicals. Thus, the smaller the foam, the greater its ability to penetrate, thus having the effect of cleaning the surface of objects with holes or complex zigzag structures, which cannot be achieved with conventional washing technology.
The following pictures describe the process of cleaning the surface of an object:
Figure 2. 4. Cleaning Process 1
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The cleaning process is involved in the creation of contact between chemicals and dirt in order for the cleaning solution to dissolve the dirt particles. This requires that the solution come into direct touch with the dust particles.
In order to accelerate the cleaning process, it is necessary to add new cleaning chemicals on a regular basis (see picture below). When chemicals dissolve dirt, a layer of chemicals near the surface of the object is gradually saturated, so its dissolving effect becomes increasingly thick, so the cleaning process is slowed down or completely lost.
Figure 2. 5. Cleaning Process 2
Ultrasonic waves boost cleaning effectiveness by preventing the creation of a saturated layer of chemicals and allowing the active layer of chemicals to come into direct contact with the surface to be cleaned. They do this by creating and striking the surface with bubble waves.
Figure 2. 6. Cleaning Process 3
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Certain dirt particles are not dissolved; instead, they are loosely adhered to the object's surface by cohesive forces or ion bonding; these particles are easily removed by pushing against the dirt with a force stronger than the dirt's adhesion force to the surface (see figure below).

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