(Đồ án hcmute) design and manufacturing of metal surface treatment machine by using cold plasma technology

TOPIC OVERVIEW

Overview of the topic

Spray coating has emerged as a popular method for surface treatment, primarily used to protect structures and components operating in various environments This technique effectively restores worn, corroded, and damaged machine parts, leading to reduced production and maintenance costs, energy savings, and a more environmentally friendly approach.

Recent advancements in equipment, materials, and technology have established spray coating as a distinct field of science and technology, significantly contributing to human progress This technique offers substantial economic benefits in manufacturing and restoring production tools Different materials and products operate under unique physical and chemical conditions, making coating technology, or surface treatment, essential across various sectors, including mechanical engineering, construction, healthcare, and environmental management.

Plasma surface treatment is a widely used process across various industries, encompassing techniques such as implanting, cleaning, sputtering, and chemically activating or coating materials This versatile treatment is effective for both heat-sensitive and heat-tolerant materials, making it essential for enhancing surface properties in diverse applications.

Coatings serve both decorative and functional purposes, offering properties such as micro and nanostructuring, bioactivity, heat resistance, and varying degrees of hydrophobicity and hydrophilicity When surface etching or cleaning is necessary, plasma technology is an effective solution, utilizing either inert gas sputtering—akin to atomic-scale sandblasting—or chemically reactive plasma etching This process results in a bright and shiny surface post-treatment Additionally, plasma can enhance the physical properties of materials by implanting energetic ions into the atomic lattice or by applying precisely engineered surface layers of doped materials.

Plasma cleaning is essential for removing contaminants from surfaces prior to manufacturing, effectively accommodating various materials and complex geometries This advanced cleaning system ensures efficient surface treatment while preserving the inherent properties of the materials Over recent decades, the effectiveness of plasma cleaning has gained recognition, leading to its widespread application in pre-processing cleaning across diverse industries.

In 2009, engineers at the Institute of Mechanical Engineering initiated a project focused on "Research and application of surface treatment technology to improve the quality of mechanical parts by plasma spraying method." This innovative coating technology, already utilized in industrialized nations, aims to protect mechanical components from rust and enhance their performance under extreme conditions, such as high temperatures and friction The research team conducted plasma spraying experiments on various mechanical equipment, including drilling machine spindles and CNC boring machines, resulting in significantly improved recovery of parts while maintaining standard specifications for long-term reuse Depending on specific working environments, wear-resistant coatings can be applied using materials like stainless steel and nickel alloys The plasma spraying method not only excels in the repair and restoration of mechanical parts but also offers substantial economic benefits, reducing costs by 50% to 60% compared to purchasing new equipment while achieving efficiency levels of 80% to 90% Additionally, this method shortens repair times, allows for on-site repairs, and is more cost-effective than imported alternatives, thus providing high economic efficiency.

In recent years, advancements in science, technology, engineering, and industry have made it essential to enhance product quality and extend the lifespan of complex structures The research and implementation of plasma spraying technology represent a significant milestone in the field of mechanical engineering in Vietnam This article will introduce plasma spraying technology and explore its applications in the manufacturing of machine parts.

Foreign research

Graduation Thesis GVHD: Assoc Prof TRAN NGOC DAM, Ph.D

Plasma technology plays a crucial role in various industries, including circuit board manufacturing, textiles, plastics, and medicine Its significance continues to grow as researchers worldwide explore innovative applications, making it a key focus in modern technological advancements.

Figure 1.1 Chemical treatment and Plasma treatment

- Currently in the world there are many surface treatment methods, but the current popular methods include:

Plasma treatment comes in two forms: atmospheric and vacuum, both of which oxidize surfaces Vacuum plasma treatment, conducted in a controlled chamber, allows for precise manipulation of gas composition and ratios, making it ideal for specialized coatings like those used on eyeglasses, despite being more time-consuming and complex In contrast, atmospheric plasma treatment uses a nozzle to draw gas from the environment, offering less control but enabling efficient treatment of small areas and seamless integration into continuous manufacturing processes on assembly lines.

The process involves discharging high-voltage, high-frequency electricity from an electrode within a ceramic tube that extends along the length of the material roll This electricity passes through the material and is directed to a grounded metal roll known as the treater roll, around which the material is wrapped.

- This interaction between the electrode and the metal roll creates a visible flash on the surface of the material roll as it moves between the two components

The process utilizes a precise mixture of natural gas and air to generate a hot, oxygen-rich plasma that effectively removes contaminants and activates surfaces through partial oxidation This technique is particularly beneficial for low-energy surfaces like plastics and composites, which can be challenging for adhesion While flame treatment offers the highest temperatures, it risks melting polymers and producing low-molecular-weight oxidized materials (LMWOM) that may hinder bonding Consequently, film manufacturers often prefer corona treatment, recognized as the coldest method among the three options.

 These are all extremely effective in preparing a surface to the proper state of cleanliness, but there are certain concerns that need to be understood and monitored:

 Parts can be under-treated or over-treated and either state can adversely impact adhesion

Parts frequently arrive at the cleaning process with differing cleanliness levels To ensure effective treatment, it's crucial to calibrate the cleaning tools according to the appropriate surface treatment level, utilizing a surface measurement inspection device for this calibration Additionally, this inspection device is vital for monitoring any changes that may occur in the treatment parameters over time during usage.

 Excessively soiled parts may not be adequately cleaned because these methods are not designed to remove oils or large particulate

 Overtreatment can volatilize and damage the surface, adversely impacting adhesion

Laser ablation is a highly precise cleaning technique that utilizes a focused, often pulsed, laser beam to remove tiny fractions of a material's surface This method effectively drills extremely small, deep holes in hard materials, creates thin films or nanoparticles, and prepares surfaces with micro- and nano-level control However, without careful monitoring, laser ablation can generate micro-debris that adheres to surfaces, making it challenging to clean Additionally, excessive treatment can lead to the material being converted into plasma.

Cleaning methods may vary, but it's crucial to recognize that unexpected contamination can occur at any stage of the process As parts move between different departments, it's vital for all personnel to understand the delicate nature of surfaces, the repercussions of neglecting proper procedures, and the risk of unintentionally introducing contaminants.

A solvent bath operates by utilizing solvent vapor to effectively break down and eliminate contaminants from material surfaces In this process, a heating coil raises the solvent's temperature, causing vapor to rise into a chamber containing the part being cleaned The vapor condenses on the surface, allowing contaminants to drip off This method is cost-effective, as the solvent can often be recovered and reused; however, it requires careful monitoring to ensure proper distillation and cleanliness Additionally, the solvent must be compatible with the material and thoroughly rinsed before the part is processed.

Chemical etching is a precise surface activation process that utilizes temperature-controlled chemical baths to selectively clean and remove material from metal parts While effective, it requires strict control to prevent chemical contamination and variations in effectiveness This technique is widely used in microelectronics and medical devices, where precision and reliability are crucial.

Viet Nam research

In Vietnam, traditional cleaning methods primarily rely on chemicals to enhance surface absorption, particularly for metal surfaces that undergo degreasing and rust removal using NaOH, HCl, and phosphate solutions before painting For low surface energy materials like glass and ceramic tiles, surfaces are heated to high temperatures before applying a coating solution, which is then maintained at this temperature for optimal adhesion However, these processes are time-consuming, cumbersome, and energy-intensive, as each stage requires separate tanks, leading to intermittent treatment and resulting in chemical residues that contribute to environmental pollution.

 Mechanics: Spray water, sand, marbles, CO2 đá rock

=> Chemical cleaning, blasting, sandblasting… are very expensive and efficient not high and pollute the environment…

 Physics: Heat, static electricity, magnetic field, laser,

=> Chemistry is very expensive, inefficient and pollutes the environment…

=> Physical adhesion should be less durable, very expensive, not high performance and affect the user

 Application of plasma technology with plasma reaction in an inert gas environment to create high-order oxidation of electrons, ions and molecules

In a plasma environment, particles influenced by an electric field exhibit significant kinetic energy, effectively cleaning dust and dirt (both organic and inorganic) from surfaces through impactful collisions This process also eliminates bacteria and fungi via advanced oxidation The energy transmitted during these collisions activates surface elements, enhancing adhesion capabilities and enabling superior coating absorption As plasma operates directly on the surface, the treatment is both rapid and efficient Overall, plasma technology offers a highly effective, economical, durable, and environmentally friendly solution for surface coating processes.

The urgency of the topic

In the mechanical engineering sector, the quality of working surfaces and the dimensional precision of machine components play a crucial role, significantly influencing the technical performance and economic efficiency of machinery Extensive research has focused on developing technological solutions aimed at enhancing both the accuracy and the quality of machine part surfaces.

Assoc Prof TRAN NGOC DAM, Ph.D., addresses the challenge of enhancing the accuracy and quality of surfaces in his graduation thesis on GVHD He emphasizes the importance of continually developing and implementing advanced processing technologies and methods to achieve these improvements.

Before applying protective layers like plating, dyeing, painting, or lubricants, it's essential to clean and enhance the absorption of machine parts Traditional cleaning methods are costly, inefficient, and environmentally harmful due to the use of toxic chemicals Additionally, products treated with protective layers often exhibit low adhesion, resulting from insufficient bonding between the part and the coating.

To address the identified disadvantages, we implement a method of applying plasma to the surface of parts at atmospheric temperature and pressure This technique effectively cleans the surface while enhancing coating absorption, resulting in a product that is not only aesthetically pleasing but also durable and capable of withstanding harsh working conditions The primary objective of our project is to treat sample surfaces to improve coating absorption, thereby enhancing the product's beauty, resistance, and durability under varying usage conditions, all while reducing production time and costs.

We design and manufacture a compact model equipped with an automatic processing speed control system to treat the surface of aluminum box bars (grade 5052, dimensions 100 x 45 x 6000 mm or larger), intended for both interior and exterior decorative applications.

In this project, we explored challenges related to plasma and surface treatment research, aiming to achieve practical applications that could significantly enhance everyday life Recognizing the project's importance, our team, guided by Assoc Prof Dr Tran Ngoc Dam, which includes students Nguyen Chanh Tin, Le Minh Thien, and Tran Manh Tuan, focused on the research, design, and manufacturing of a surface treatment system for aluminum box bars (aluminum grade 5052, measuring 100*45*6000 or larger) This system is intended for use as decorative bars in both interior and exterior applications, utilizing cold plasma technology.

Scientific and practical significance of the topic

1.5.1 Scientific significance of the topic:

Today, our energy sources include oil, coal, and water, which are essential for production, transportation, and even space exploration However, these resources are finite and will eventually run out, necessitating the search for alternative energy solutions One significant alternative is atomic energy, which offers a large supply but poses risks and environmental pollution challenges.

- One type of material that has been discovered to potentially replace and carry large, high-energy reserves is Plasma This type of matter makes up 99% of the universe

- Plasma surface treatment method is a method capable of bringing high economic efficiency, it has been put into research and has a few applications in Vietnam

Plasma technology plays a crucial role in various industries, making it a significant focus of global research Currently, its applications span multiple sectors, including the manufacturing of circuit boards, textiles, plastics, and medical devices, highlighting its importance in modern production processes.

Plasma surface treatment is a widely used process across various industries, encompassing techniques such as implanting, cleaning, sputtering, and chemically activating or coating materials This versatile method is effective for both heat-sensitive and heat-tolerant materials, making it essential in numerous applications.

Coatings serve not only decorative purposes but also offer a range of functional properties, including micro and nanostructuring, bioactivity, heat resistance, and hydrophobic or hydrophilic characteristics Plasma treatment is an effective method for etching or cleaning surfaces, utilizing either inert gas sputtering—similar to sandblasting at the atomic scale—or chemically reactive plasma etching Both techniques result in a bright and shiny surface post-treatment, enhancing the material's overall performance and aesthetic appeal.

Plasma treatment can modify the physical properties of materials by embedding high-energy ions into the atomic structure or by applying precisely engineered surface layers of doped substances.

Cleaning is essential for removing contaminants from surfaces prior to their use in manufacturing Plasma cleaning is effective on various materials, including those with complex geometries, and it efficiently cleans surfaces without adversely affecting their properties In recent decades, the effectiveness of plasma cleaning has gained recognition, making it a popular choice for pre-processing cleaning of materials.

1.5.2 Practical significance of the topic:

- Along with the strong development of equipment, materials and technology in recent years, spray coating has become a separate science and technology field,

Assoc Prof TRAN NGOC DAM, Ph.D., has made significant contributions to the scientific advancement of humanity through his graduation thesis on GVHD, highlighting the economic efficiency of manufacturing and restoring production tools Different materials and products operate in unique environments, each exhibiting distinct physical and chemical effects Consequently, coating technology, or surface treatment, is essential across various fields, including mechanical engineering, construction, healthcare, and environmental applications.

- Typically, some materials such as steel, iron, copper, aluminum, wood after treatment achieved encouraging results:

- Improve the surface gloss smoothness of the part by two to three levels

- Production cost and low cost, easy to apply to production facilities

Research objectives of the topic

1.6.1 General objective of the topic

 Learn about surface treatment technology using plasma technology

 Study the principle of the system

 Fabrication and assembly of modudel assemblies in the system

 Empirical, performance assessment, complete the system

1.6.2 Specific objectives of the topic

• Design and manufacture machine for surface treatment of aluminum box bar (aluminum grade 5052, size 100*45*6000 or larger) used as interior and exterior decorative bar

• Aluminum box surface treatment machine with a capacity of 2m/min/bar (maximum 2 bars of 100*45*6000 at the same time)

• The machine's components and systems are optimally designed, compact, and space- saving to fit small and medium factory spaces

• Determine the relationship of voltage, current, speed and processing time for a number of different materials

• Semi-automatic billet feeding mechanism, workpiece transfer mechanism and automatic workpiece handling using PLC

By utilizing the principle of current amplification, two high-voltage and high-frequency electrodes are generated, operating at 5-20 kV and 5-40 kHz This setup creates a significant electric field that ionizes the air between the electrodes, resulting in the formation of a plasma beam.

 Optimize the listed principle options, choose the right plan to ensure the machine operates at the right capacity, meeting the requirements of the topic

 Clearly define the production method and productivity to make the machine work at its best

 Design the billet transfer unit to match the machine capacity

 Design and optimize the plasma chamber for the most efficient processing

 Circuit design and easy-to-use control panel

 Calculate power, force, torque, and plasma nozzle parameters

 Choose the right processing plan

 Determination of surface quality before and after treatment

 Check productivity and machine durability

Research Methodology

To effectively research documents, it's essential to consult both domestic and international scientific books and journals that focus on machine building processes This includes studying the design and calculation methodologies, as well as understanding the working principles of each component within the transmission system and engine, guided by insights from instructors.

Conducting an actual market survey involves visiting enterprise factories to manage operations, perform machine tests, and ensure safe installation and operation This includes experimental surface treatment trials, leading to valuable evaluations and insights Additionally, a review of existing surface treatment machine systems on the market allows for comprehensive evaluation and comparison of their design and principles.

- Refer to previous plasma surface treatment system design documents

- Apply the basic knowledge of machine detail principles, material strength, technical drawings, measurement technology tolerances, materials,

- Conduct testing, analysis and evaluation of experimental results to adjust technical parameters.

The order of implementation of the project

The structure of the graduation thesis consists of 7 chapters:

 Chapter 3: The Principle of a metal surface treatmentmachine by using cold plasma technology

 Chapter 4: Design and Calculation Parts

 Chapter 5: Design and Calculation Electrical parts

 Chapter 6: Manufacturing, Testing and End Evaluation

 Chapter 7: Conclusion and Development Direction

THEORETICAL BASIS

Plasma Technology Research

Plasma, one of the four fundamental states of matter alongside solids, liquids, and gases, was first described by chemist Irving Langmuir in the 1920s It is composed of ions, atoms that have lost some electrons, and free electrons This state of matter exists in various forms throughout nature and makes up over 99% of the visible universe, including stars, solar wind, comet tails, auroras, and lightning.

Plasma is typically generated in laboratory settings by discharging inert or molecular gases like argon, helium, oxygen, and nitrogen, using various power sources such as AC, DC, RF, or microwave This process creates an electromagnetic field strong enough to ionize the gas, making it increasingly conductive by removing electrons from the atomic nucleus, resulting in positively charged ions.

Plasma is a gaseous substance where electrons are accelerated by a strong electric field, gaining significant energy These high-energy electrons collide with gas molecules and atoms, transferring their kinetic energy and causing excitation, decomposition, and ionization, ultimately leading to the formation of plasma.

Plasma can be categorized according to several factors, including temperature, ionization level, and the correlation between wave phase velocity and electron thermal velocity.

Based on temperature, can be divided into low-temperature plasma and high- temperature plasma:[7]

 Low-temperature plasma (< 70,000 o C) is further divided into two branches:

- Thermally unbalanced plasma (cold plasma): The electron temperature is much greater than the ion temperature For example, fluorescent bulbs, luminescent discharges, plasma televisions, etc

- Plasma thermal equilibrium: The electron temperature is equal to the ion temperature.e Plasma torch, electric arc,

 High-temperature plasma (> 70,000 o C): occupies 99% of the universe, e.g the sun, stars, galaxies, hydrogen bombs, fusion reactions

Based on the degree of ionization, plasma is divided into: [7]

 Fully ionized plasma: Where this occurs at high temperatures, the properties of the plasma are determined by the properties of the electron and the ion contained within it

 Partially ionized plasma: Occurs in almost all cases of man-made plasma, containing free electrons and electrically neutral molecules

An ion is defined as an atom or group of atoms that has either lost or gained electrons When an atom gains one or more electrons, it becomes negatively charged and is referred to as an anion Conversely, when an atom loses electrons, it carries a positive charge and is known as a cation The process through which ions are formed is called ionization.

Ionization energy refers to the energy needed to remove an electron from an atom or molecule in its ground state Specifically, the nth ionization energy is the energy required to detach the nth electron after the previous (n-1) electrons have already been removed In this context, the ground state signifies that the atom is free from external magnetic influences, typically characterized by a gaseous state and a fundamental electron configuration.

The degree of ionization is the ratio of the concentration of charged particles to the concentration of gas particles in the environment

𝑛 0 β: the degree of ionization ne,i: concentration of charged particles

N0: concentration of gas particles in the environment For strongly ionized plasma: β> 𝜎 𝑒𝑜

𝜎 𝑒𝑖 ion σei: effective cross section, characterizing the interaction between electrons and σwaist: efficient cross section, characterizing the interaction between electrons and neutrinos

Graduation Thesis GVHD: Assoc Prof TRAN NGOC DAM, Ph.D.

Conveyor

A conveyor is a mechanical system designed to transport objects and goods efficiently from one location to another It is especially beneficial for moving heavy or bulky materials, offering a more effective alternative to manual labor, which can be time-consuming and costly By utilizing conveyor systems, businesses can achieve faster transportation of diverse materials, reduce labor costs, minimize the workforce needed, and ultimately enhance productivity.

 Rubber conveyor: Is a material transportation system that brings very economic efficiency with high conveyor belt system by rubber conveyor Rubber conveyors can be installed in any terrain and space

 Chain conveyors: Used extensively in industries to transport heavy loads such as pallets, grid boxes, and industrial containers

 Roller conveyors: Including plastics, PVC rollers, galvanized steel rollers, Roller conveyors are quite suitable for transporting light to medium to very heavy weight products

 PVC conveyor: It is a very popular conveyor, especially in the electronics industry PVC conveyors have the advantage of high durability but cheap price, so they are used quite commonly

A vibrating conveyor is a specialized conveyor system made up of a conveyor frame, roller system, conveyor wire, and inverter controller It efficiently transports small-sized goods with stability and continuous operation, enhancing productivity and production efficiency in various processes.

A heat conveyor is designed for excellent heat resistance, making it ideal for transporting dry products directly on the conveyor belt This type of conveyor utilizes heat-resistant materials, such as PU belts or stainless steel belts, ensuring durability and efficiency in high-temperature environments.

PU conveyors feature a structure akin to PVC conveyor belts, but they offer superior quality The wires used in PU belts are free from toxic substances, making them highly suitable for use in the food industry.

A Programmable Logic Controller (PLC) is a device designed for programming and executing logic control algorithms It processes external events through inputs and generates responses via outputs By continuously scanning input and output states, a PLC detects changes in input signals, which trigger corresponding adjustments in outputs based on the established logic program.

FACULTY FOR HIGH QUALITY TRAINING 17

- The current popular PLC programming language is Ladder, Step Ladder However, each manufacturer will have its own programming languages Popular PLC manufacturers today include: Siemens, Mitsubishi, Rockwell, INVT, Delta

- An inverter is a device that converts alternating current at one frequency into alternating current at another frequency that can be adjusted

An inverter is a device that adjusts the frequency of the current supplied to a motor's coil, enabling precise, stepless control of motor speed without mechanical gearboxes By utilizing semiconductor components, the inverter sequentially switches the current in the motor's windings, creating a rotating magnetic field that drives the motor's rotation.

Inverters come in various types, including AC and DC inverters, as well as specific models like 220V single-phase, 220V 3-phase, and 380V 3-phase inverters Additionally, manufacturers offer specialized inverters tailored for specific applications, such as pumps, fans, lifting and hoisting systems, elevators, and air conditioning systems.

An inverter is designed to convert a fixed frequency input voltage into a variable frequency voltage, enabling precise motor speed control Key components of the inverter include the rectifier, filter, IGBT inverter, and control circuit Additionally, it integrates various other elements such as AC and DC reactors, braking resistors, a keyboard, a display screen, and a communication module.

Inverter

- An inverter is a device that converts alternating current at one frequency into alternating current at another frequency that can be adjusted

An inverter is a device that adjusts the frequency of the current supplied to a motor's coil, enabling precise control of motor speed without the need for mechanical gearboxes By utilizing semiconductor components, the inverter sequentially switches the current to the motor's windings, creating a rotating magnetic field that drives the motor's rotation.

Inverters come in various types, including AC and DC inverters, as well as specific models like 220V single-phase, 220V three-phase, and 380V three-phase inverters Additionally, manufacturers offer specialized inverters tailored for specific applications, such as pumps, fans, lifting and hoisting systems, elevators, and air conditioning systems.

An inverter is designed to convert a fixed frequency input voltage into a variable frequency output voltage, enabling precise motor speed control Key components of an inverter include the rectifier, filter, IGBT inverter, and control circuit Additionally, it often incorporates various elements such as AC and DC reactors, braking resistors, a keyboard, display screen, and communication modules, enhancing its functionality and performance.

THE PRINCIPLE OF A METAL SURFACE TREATMENT

System overview

Overview of metal surface treatment machines

Figure 3 1 System overview principle diagram

When powered on, the system activates with a red light Pressing the START button feeds the workpiece onto the conveyor belt, triggering the 1-end conveyor sensor and illuminating the yellow light, indicating that the conveyor is operational Once the workpiece contacts sensor 2, the green light activates, signaling that the plasma chamber is in operation The green light will turn off after the process, while the conveyor continues to run, and the yellow light shifts to standby mode If sensor 2 does not detect a signal for 5 seconds, the plasma chamber will cease operation, resulting in a complete system shutdown.

Table 3 3 List of nozzle manufacturing options

- The spray area is small, narrow

- Spray evenly on the surface

- Simple fabrication, large covering area

Through evaluation and comparison, we decided to choose option 2 to design and manufacture plasma nozzles

Working principle of plasma nozzles: based on the principle of using inert gases

Under high pressure between the anode and cathode, gases are ionized at extremely high temperatures due to the arc's influence, creating a plasma flow This plasma is expelled through a nozzle at high velocity, while spray powder is drawn into the air stream, melted, and then sprayed onto the surface of the detail for coating.

Figure 3 2 Plasma nozzle working principle diagram[14]

3.2.2 The principle of operation of the machine:

Figure 3 3 System principle diagram option 1

The machine operates on a 220V power supply, with an aluminum bar positioned on a conveyor aligned with a sensor mounted on an aluminum profile (sensor Z:25, Y:20mm from the quartz tube) Once powered and the sensor is activated, pressing the start button initiates the conveyor and plasma chambers As the aluminum rod receives the electrode charge, sound from the conveyor and anode infuses into the stainless steel rod within the quartz tube, generating an electric field and ionizing air between the electrodes, which effectively processes the plasma on the aluminum bar's surface.

If the sensor fails to detect a signal from the detail, pressing the start button will prevent the conveyor belt and plasma nozzle from operating Once the processing is finished, the conveyor will release the treated aluminum rod However, if the sensor does not receive a signal within 5 seconds, it will automatically shut off both the conveyor and plasma supply.

The treatment process involves transferring one end of the electrode into an aluminum bar via a roller conveyor, while the other end connects to a stainless steel rod When a high voltage power supply of 22kV is applied, ionization of the air between the electrodes occurs, generating plasma for effective surface treatment.

- Easy to maintain and repair

- The contact distance of the plasma nozzle cannot be adjusted

The machine operates on a 220V power supply, utilizing a conveyor belt to position an aluminum rod in front of a sensor mounted on an aluminum profiled frame (Z:25 conveyor face sensor, quartz tube way Y:20mm) Once powered, the system activates when the sensor detects a signal, allowing the start button to engage the conveyors and plasma chambers The aluminum rod receives a negative electrode from the conveyor, while an anode is introduced into a stainless steel rod within the quartz tube, generating an electric field This process ionizes the air between the electrodes, creating a plasma treatment on the surface of the aluminum bar If the sensor fails to detect the rod, pressing the start button will not activate the conveyors or plasma nozzle.

Assoc Prof TRAN NGOC DAM, Ph.D., presents a graduation thesis on GVHD, detailing a process where a conveyor system efficiently delivers aluminum rods with treated surfaces If no signal is detected by the sensor within five seconds, the dynamic conveyor and plasma chambers automatically deactivate The innovative 3-axis mechanism allows the plasma chamber to effectively process products with significant surface areas and heights.

The treatment process involves transferring one end of the electrode into an aluminum bar via a roller conveyor, while the other end connects to a stainless steel rod When a high voltage power supply of 22kV is applied, it ionizes the air between the electrodes, generating plasma for effective surface treatment.

- Can handle parts with large surface and height

The machine operates on a 220V power supply, requiring the aluminum rod to be placed on the left tapei, connected to one end of the electrode Once powered, if sensor 1 activates with a bright red light, pressing the start button initiates the left bandi (indicated by a yellow light), allowing the workpiece to enter the plasma chamber When the aluminum rod aligns with sensor 2, which then lights up green, the plasma chamber activates The rod's contact with the electrode and the stainless steel rod in the quartz tube generates an electric field, ionizing the air to create plasma for surface treatment If sensor 1 fails to detect the rod, the conveyor remains inactive, preventing system operation After treatment, the conveyor removes the aluminum rod, and if sensor 2 does not signal for 5 seconds, the END button triggers to halt the conveyor and plasma operation The plasma chamber's distance from the part's surface can be adjusted manually using a 200mm stroke feed screw mechanism.

The treatment process involves transferring one end of the electrode into an aluminum bar via a roller conveyor, while the other end connects to a stainless steel rod When a high voltage power supply of 22kV is applied, it ionizes the air between the electrodes, resulting in the generation of plasma for effective surface treatment.

- Easy to maintain and repair

- Optimizing machines for automatic industrialization

- There is no automatic billet feeding system

3.2.3 The principle of operation is best

Table 3 4 Comparison table of principle schemes of metal surface treatment

• Easy to maintain and repair

• The contact distance of the plasma nozzle cannot be adjusted

• Easy to maintain and repair, cheap price

• Can handle product with large surfaces and heights

• It is possible to handle details with a large surface and height

• Optimizing machinery for automatic industrialization

• There is no automatic billet feeding system

• In accordance with the requirements of the Vietnamese market in terms of cost, performance and durability, easy maintenance and repair

Based on the comparison table of the above criteria, my team decided on option 3 as the principle of operation Dynamic of cold plasma technology metal surface treatment machine

Figure 3 6 Complete system principle diagram

The machine operates on a 220V power supply, requiring the placement of an aluminum rod on the left tape, which connects to one end of the electrode Once powered, if sensor 1 activates (indicated by a bright red light), pressing the start button initiates the left bandi (yellow light), allowing the workpiece to enter the plasma chamber When the aluminum rod reaches sensor 2, it activates (bright green light), enabling the plasma chamber to function This process ionizes the air between the two electrodes, creating plasma for surface treatment of the aluminum rod If sensor 1 fails to detect the workpiece, the left i tape will not operate, preventing system activation After treatment, the conveyor removes the processed aluminum rod, and if sensor 2 does not detect a signal within 5 seconds, the END button is triggered to halt the conveyor and plasma chamber, stopping the system Additionally, the plasma chamber features a manually adjustable 200mm stroke feed screw mechanism to modify the distance between the quartz tube and the part surface.

The treatment process involves transferring one end of the electrode into an aluminum bar via a roller conveyor, while the other end connects to a stainless steel rod When a high voltage power supply of 22kV is applied, it ionizes the air between the electrodes, resulting in the generation of plasma for effective surface treatment.

Sequence of proceedings

DESIGN AND CALCULATION PARTS

Material

To ensure the durability, safety, and aesthetics of the treatment system, which is installed in an environment exposed to natural air, it is essential to use antioxidant and insulating materials to prevent oxidation of the components over time.

We choose the following materials:

The glass pipe features a 25mm outer diameter and a 2mm thickness, designed to withstand high temperatures of up to 1730 degrees Celsius Constructed from durable quartz, it is resistant to corrosion from various substances, including HF acid, and maintains chemical stability even under extreme conditions This material also allows for the transmission of light across the entire ultraviolet and infrared spectrum, making it possible to observe the striking purple plasma generated by the energy of the plasma rays.

 Glass tube holders group select composite materials with reinforced bearing fibers for strong oxygen resistance and best insulation

 The detailed catch tube is made of stainless steel

 The conveyor must be made of profiled aluminum for good oxidation resistance and insulation

 The "COVER" of the plasma chamber is made of stainless steel (3mm thick).

Calculation and design

 Output voltage 600VAC max – 40kHz

 Plasma generation: 10kV – 45kV with a frequency of 50Hz – 10MHz

Application: Surface treatment - water and exhaust gases and another successful application is reforming gas

4.2.1.2 Calculation and design of plasma nozzles

 Inlet gas flow and pressure

Experiments conducted by varying airflow in the system revealed that an optimal flow rate of 5-15 liters per minute, measured using a stopwatch, yielded the best results.

The pressure at the treatment area is equal to atmospheric pressure

Table 4 2 Conditions for generating a spark

DISTANCE BETWEEN TWO POLES (mm)

In order for a discharge to occur, the electric field strength must reach a threshold of about [3x10 6 V /m]

The processing tube unit features a coaxial quartz pipe with an inner diameter of 25mm and a thickness of 3mm Inside the pipe, a positively charged metal rod is insulated, while the outer layer consists of a negatively charged quartz pipe envelope.

With the maximum voltage the power supply can achieve is 10-45KV, so we choose a distance between the two electrodes of 5 mm

 Temperature at the plasma treatment zone

Experimental plasma generators are non-thermal plasma sources, so the heat emitted depends only on the temperature of the electron Here is a temperature table of several types of plasma:

Cold plasma operates at temperatures between 27°C and 727°C (300 to 1000 K) To ensure optimal performance of the plasma chamber, we utilize quartz pipe as the insulation material, which has a melting point of 2000°C.

With good heat resistance requirements, and high discharge efficiency, we choose a positive stainless steel electrode (the melting point of stainless steel 304 is 1400-1450 °C) with parameters of 1 mm x 124 mm

 Choose a quartz hydro pipe with an outer diameter of 25 mm thickness 3 mm, length 250 mm

 Heat-resistant, chemically corrosive quartz pipe

 Have a place to mount devices in the system: Must be insulated, insulated and strongly anti-oxidant Do not let plasma gas fly out

 Limit the penetration of dust and insects into the system

 Can be opened easily when maintaining or replacing mechanical parts

 The details are mostly made of stainless steel

4.2.2.1 Pillows for quartz tube (right)

 Concentric assembly must be assembled between the supporting pillow and the glass tube

 It must be placed on a highly solid base, so that the power cords connect to the stainless steel pipe in the glass pipe easily

 Resistant to high temperatures and strong antioxidant

 Based on the requirements set, my group is divided into 2 parts:

 Must be positioned 5 degrees of freedom: translational X, translational

Y, translational Z, rotation around axis X, rotation around axis Z

 There must be a tightening M5 bolt to hold the glass tube in place

 The two supporting pillows should be the same and are caught on the same plane

 A hole with an inner diameter of ỉ = 25.5mm to the jig of a glass pipe (quartz pipe) with an outer diameter ỉ = 25mm

 A hole ỉ = 5mm next to hole ỉ = 25.5mm to hold the jelly pipe fixed

Figure 4 3 Right pillows for Quartz tubes

Figure 4 4 Right pillows for Quartz tubes model

4.2.2.2 Pillows for quartz tube (left)

 Concentric assembly must be assembled between the supporting pillow and the glass tube

 It must be placed on a highly solid base, so that the power cords connect to the stainless steel pipe in the glass pipe easily

 Resistant to high temperatures and strong antioxidant

Y, translational Z, rotation around axis X, rotation around axis Z

 A hole with an inner diameter of ỉ = 25.5mm to the jig of a glass pipe (quartz pipe) with an outer diameter ỉ = 25mm

 Two holes ỉ = 5mm to catch the M5 bolt into the support pillow holder and then squeezed by the M5 nut

 A hole ỉ = 5mm next to hole ỉ = 25.5mm to hold the jelly pipe fixed

Figure 4 5 Left pillows for Quartz tubes

 Assembly must be coaxial with stainless steel bar

Y, translational Z, rotation around axis X, rotation around axis Y, rotation around axis Z

 Two holes ỉ = 5mm to catch the M5 bolt into the support pillow holder and then squeezed by the M5 nut

Figure 4 6 Quartz tube fixed part

 The frame is subject to high heat and oxidation

 The size is suitable for the machine

 The tolerances of symmetrical holes must be small

 The frame will be perpendicular to the profiled aluminum of the conveyor through a 90-degree eke

 The inner dimension of the frame should be about 1-2 mm above the T-detail to avoid a size deficiency error

 The holes of the T-section caught in the frame must coincide with the knees supporting the glass tube

 Bag size: 436mm x 500mm x 150mm and 3mm thick detail

 The two holes ỉ = 4mm are designed together with the T-detail to prevent the assembly from being misaligned

 From the exterior of the frame to the T-th detail, the size of the frame is divided into 250mm for ease of construction

 From there we can equally divide the remaining dimensions to fit the frame

Figure 4 7 Detail drawing of plasma frame

 Changing the conveyor speed retains the allowable stable torque

 Conveyor transfer speed: vmax = 10 m/min = 0.167 m/s

 Power on the working shaft:

Inside: k: The coefficient depends on the conveyor length k = 1.10 when L =(16÷30)m k = 1.05 when L =(30÷45)m c: Conveyor width dependent coefficient, look up table 3.1

Table 4.3 Conveyor width-dependent coefficient

 Speed of rotation of the impeller shaft

D (mm): Conveyor drive tang diameter

 Selecting the engine and distributing the gear ratio

𝜇 = 𝜇 𝑛𝑡 𝜇 𝑏𝑟 1 𝜇 0 2 𝜇 𝑑 = 1 0,95 = 0,890,97 2 0,99 3 According to table 2.3 [5], we have:

𝜇 𝑏𝑟 = 0,97: Efficient of a pair of gears

𝜇 𝑜 = 0,99: Efficient of a pair of rolling bearings

- Power required on the motor shaft:

- Preliminary determination of the number of revolutions of the engine:

In it: 𝑢 𝑠𝑏 = 𝑢 𝑑 𝑢 ℎ 𝑢 𝑛𝑡 = 3.8.1 = 24 is the preliminary gear ratio of the system

𝑛 𝑡ả𝑖 is the rotational speed of the working shaft

 Select a motor: the engine must meet the following conditions:

Pct ≤ Pc nđb = 750(vg/min) Table 4 4 Engine parameters M2QA71M6A

- Real transmission ratio of the system:𝑢 𝑡 = 𝑛 𝑑𝑐

𝑢 𝑏𝑟 = 5 2-speed cylindrical gear gear gear ratio section 2.4 [15]

Calculate HGT external gear ratio: 𝑢 đ = 𝑢 𝑡

𝑢 𝑡 is the general gear ratio

𝑛 𝑑𝑐 is the gear ratio of the engine

𝑛 𝑡ả𝑖 is the gear ratio on the working axis

Check the allowable error of the gear ratio: Δu= |𝑢 𝑡 −𝑢|

13,795 = 0,6% < 5% satisfies the allowable error condition Calculate the number of revolutions on the shafts:

Calculation of power on the axes:

0,99.0,97 = 4,196 (KW) Motor shaft: 𝑝 đ𝑐 = 𝑝 1 à 𝑜𝑙 à đ = 4,46 (KW) Calculate moments on axes:

 Fixed by two bearings containing roller rings (fit tightly)

 High heat and oxidation resistance

 Tolerance on diameter and length between rollers is not too large

 Located 5 degrees of freedom: Forward in X,Y,Z and rotated in Y,Z direction

 The shaft diameter length for roller mounting is 50mm and 8mm respectively

 Ensure wear and friction when operating for a long time

 Replaceable when damaged or broken

 Assembly between the bearing and the tight-fitting roller shaft

 Located 6 steps by : Straight forward in X,Y,Z and rotated in X,Y,Z

 One hole for mounting the roller shaft size ỉ30mm

Figure 4 11 Shaft support detailed drawings

 Must be assembled concentrically between the motor shaft and the hole of the part

 Assembling on the chassis must be sturdy

 High temperature resistance and strong oxidation resistance

 Rectangle with dimensions 75mm ×105 mm

 4 holes 4mm diameter for motor mounting

 2 step holes 6mm and 8D8mm

 1 hole diameter 30mm for motor shaft mounting

 Fixed electrical cabinets and conveyors

 High heat and oxidation resistance

 4 holes 5 for assembly between electrical cabinet and conveyor

Figure 4 13 Electrical cabinet support plate

 Ensure safety when the conveyor is in operation

 High resistance to heat, abrasion and oxidation

 L-shaped details with a thickness of 3mm

 10 holes size R5*20(SLOT) for fixing

System Design Overview

Figure 4 15 Drawings of total system design

DESIGN AND CALCULATION ELECTRICAL PARTS

Design Requirements

For the metal surface treatment machine control system to operate reliably and effectively, it must fulfill the machining requirements and ensure the proper functioning of the drive motor Additionally, the control system should meet essential criteria to guarantee optimal performance.

 There must be an emergency stop button

 There is a use of signal lights

 Electrical system, simple and easy to use interactive interface

Hardware Control

The deceleration motor plays a crucial role in various electrical equipment designed for speed reduction This type of electric motor operates at a significantly lower RPM compared to traditional motors with equivalent power and pole numbers Depending on the application, the speed can be decreased by factors such as 1/2, 1/3, or 1/5, making it a versatile solution for deceleration needs.

 The design is compact, has a large gear ratio

 Stable, durable, long service life

 The engine causes a lot of interference and vibration

MCB PS45N C25 Vanlock automatic circuit breaker is an automatic circuit breaker that automatically disconnects the current when a short circuit or overload occurs, protecting electrical equipment

The machine operates mainly in the range of 24VDC and 5VDC voltage, so we use 24VDC honeycomb power to supply the motor and the entire circuit system

A relay is an essential electrical device that enables the operation of switches through electrical signals Widely utilized in automatic control systems, relays facilitate the management of high currents that circuit systems cannot directly handle, ensuring efficient and safe operation.

Figure 5 5 Infrared Obstruction Sensor E3FDS100C4 [25]

The proximity sensor detects metals within a range of 0-4mm, signaling to the machine controller when it has reached the limit or home position.

- Output: NPN extremely open receiver

Instruments Image Function Num ber amou nt

Report the operating status in the electrical circuits

Close the dynamic source switch, disconnect the circuit when there is a problem

3 Domino 12 legs Connecting electrical wires to control devices

4 CB 1 phase 220V Open and close the power supply for the machine

Report the dynamic status of the sensor 2

System control diagram

 The control circuit must have an emergency stop button, power button and signal light

 The symbols of push buttons and indicator lights are clear, reasonably easy to recognize

 There are Auto and Manual modes

 It is possible to change the plasma chamber voltage and inverter

MANUFACTURING, TESTING, END EVALUATION

Mechanical fabrication and assembly

Table 6 1 Specifications of the machine

 Stainless steel materials against rust

 Withstand vibrational gravity loads when vibrating the workpiece level

Figure 6 3 Stainless steel bars Figure 6 4 20x20 profiled aluminum bar

Figure 6 5 Quartz pipes Figure 6 6 Plasma processing nozzle

 Stainless steel materials against rust

 Sealed treatment chamber design with power and gas ducts

Manufacture and assembly of electrical cabinets

Figure 6 7 The front of the electrical cabinet

Figure 6 8 The inside of the electrical cabinet

 Cold rolled steel cabinet material with a thickness of 1mm is powder coated with a total size of 300x400x150

Overall system

Figure 6 9 Metal surface treatment system by cold plama technology

Run an experiment

After assembling, calibrating the entire machine, conducting electrical closure and testing of machine operation

Before conducting a machine operation test, it is necessary to check the entire machine:

 Check the power cable lines for scratches, breaks If there is a need to carry out repairs immediately

 Check the switches to see if they are ready for the system to work

 Check whether there are obstructions or foreign objects inserted into the machines,

 Check the machine parts for distortion or failure after the assembly process

After inspecting the machine and confirming there are no abnormalities, proceed to power it on for operation Additionally, ensure that the circuit breaker for the entire connected system is turned off to maintain stable functionality.

Evaluation criterion

The evaluation criteria are based on the set goals of the topic:

 Aimed at the treatment audience are businesses interested in surface quality

 Compact design, automation control, easy operation, maintenance, cost saving

 High processing efficiency, using modern green technology - Plasma technology

 The output quality meets the standards according to national technical regulations on the quality of surface cleaning.

Rating

Through the test run, the metal surface treatment system has the following assessments:

 Meet the requirements of line processing

 Solvingsurface treatment problems, increasing productivity: less system installation area, low investment capital, long-term use

 Compact design, easy to operate, fast maintenance, inexpensive: the machine has dimensions: 1620x374x765, installing the whole system takes 3m 2

 High processing efficiency thanks to the use of Plasma technology:

 Surface treatment achieves a yield of 2÷4m/min

CONCLUSION AND DEVELOPMENT DIRECTION

Conclusion

Our research into green treatment technologies has highlighted their significant impact on surface treatment processes Consequently, we have developed and implemented an innovative machine treatment system that utilizes plasma technology, specifically designed for metal surface treatment applications.

Through extensive analysis and comparison of various design options, we have identified the optimal design principle for the system, grounded in the fundamental surface treatment principles of plasma technology.

We have successfully designed and manufactured a plasma technology-based metal surface treatment system with a capacity of 2 to 4 meters per minute, effectively achieving our group's objectives Plasma technology offers significant advantages for metal surface treatment systems, enhancing efficiency and results.

 Compact, easy to operate, maintain maintenance, minimize installation area

 Plasma technology does not use chemicals for processing which further contributes to protection, safety and environmental friendliness

 Energy saving, maximum shortened processing time while still producing the best results

 High processing efficiency: the output surface quality meets national standards

 Save installation, operation and maintenance costs

This article explores the optimal solution for treating metal surfaces using plasma technology, aiming to enhance productivity and surface treatment quality By implementing this advanced method, we contribute to the innovative development of the country.

After completing the design and manufacture of the metal surface treatment system, the team realized that the topic still had many shortcomings and offered some development directions as follows:

Continue to research and develop the system, optimize energy to help the operation of the system use the lowest energy source but still achieve the highest efficiency

Improve the automatic ability of the machine, the machine runs fully automatically, can run when the water quality is low

Optimize investment costs for production and machine productivity

Improving the processing capacity of the system helps to expand the scale of machine use

Research and develop plasma technology applied to many different fields such as agriculture, fisheries

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2615.html#:~:text=Motor%20gi%E1%BA%A3m%20t%E1%BB%91c%20l%C 3%A0%20b%E1%BB%99,t%C3%B9y%20thu%E1%BB%99c%20v%C3%A0o

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Tiêu đề	Design and manufacturing of metal surface treatment machine by using cold plasma technology
Tác giả	Nguyen Chanh Tin, Le Minh Thien, Tran Manh Tuan
Người hướng dẫn	Assoc. Prof. Tran Ngoc Dam, Ph.D.
Trường học	Ho Chi Minh City University of Technology and Education
Chuyên ngành	Machine Manufacturing Technology
Thể loại	Graduation project
Năm xuất bản	2023
Thành phố	Ho Chi Minh City

Định dạng
Số trang	86
Dung lượng	4,87 MB