Study On The Durability Of Flexible Moment Mechanisms With Various Types Of Plastic Materials.pdf

DO THANH TRUNG TANG THAI KHANG 19144081 Year of Admisssion: 2019 – 2023 Ho Chi Minh City, March 2024 Major: Mechanical Engineering Technology STUDY ON THE DURABILITY OF FLEXIBLE MOM

INTRODUCTION

Reason for choosing the topic

The selection of the experimental topic on the durability of moment-resistant structures is motivated by several important reasons stemming from practical needs in the field of torsional strength Here are some specific reasons:

1 Real-world application: The selected topic focuses on a specific and essential issue in the practical context to generate applicable knowledge with value in fields utilizing flexible moment-resistant structures

2 Torsional strength: With the increasingly robust development of industry and technological applications, the torsional strength of flexible moment-resistant structures has become a decisive factor in performance and safety across numerous applications

3 Material diversity: The utilization of common plastic materials such as ABS, PP, PA6, and HDPE enables the research to reflect diversity in applications and material selection for flexible moment-resistant structures depending on the specific project requirements

4 Experimental research demand: Conducting direct durability tests on flexible moment-resistant structures is essential to gather accurate data and information regarding the performance of materials under real operating conditions

5 Wide-ranging applications: The outcomes of the project can be applied across various fields such as industry, automation, healthcare, and numerous other applications where flexible moment-resistant structures play a crucial role

The reasons above illustrate the necessity and significance of choosing this experimental topic, guiding the approach and detailed research in the subsequent sections of the project.

Research objectives

The aim of the experiment is to assess and compare the torsional strength of flexible moment-resistant structures when using different types of plastic materials Specifically, the research focuses on:

− Performance identification: measuring and comparing the torsional strength capabilities of flexible moment mechanism with each type of plastic material used

− Material optimization: identifying which plastic material yields the best performance under torsional conditions, aiming to optimize design and application in real-world scenarios

− Providing theoretical basis: establishing a solid theoretical foundation and accurate experimental data to support the design process and material selection for flexible moment-resistant structures in various application

− This experimental objective helps clarify the research direction and provides valuable results to support the development and application of flexible moment-resistant structures in various industries.

Object of research scope

− The research focuses on flexible moment mechanism and their interaction with various plastic materials The primary experimental subjects are models of flexible moment-resistant structures manufactured from specific plastic materials such as ABS, PP, PA6, and HDPE

− The research scope includes the evaluation of the torsional strength of flexible moment-resistant structures with the aforementioned plastic materials The objective is to understand the capabilities and limitations of flexible moment- resistant structures under real-world conditions through experiments and measurements of their torsional strength characteristics

− This experimental scope will help establish a valuable database for the design and application processes of flexible moment-resistant structures, while providing specific information regarding the torsional strength capabilities of plastic materials for specific applications.

Approach and research methods

− The research utilizes a direct experimental method on flexible moment- resistant structures to assess torsional strength This method involves applying controlled torsional forces while measuring and recording relevant parameters

− The experimental tools include torque measurement devices, durability testing machines, and other measuring instruments aimed at collecting accurate data on the performance of flexible moment-resistant structures under torsional forces These tools ensure the accuracy and reliability of the data collected from the experiments

− The experimental methods and tools are carefully selected to ensure that the results obtained from the tests are reliable and applicable for evaluating and improving the performance of flexible moment-resistant structures with different materials

Topic limitation

During the implementation process, the project encountered several significant limitations that affected the research process and the results obtained The main limitations include:

− Technical limitations: Due to technical constraints and equipment limitations, the study could not encompass all factors and conditions that may influence the torsional strength of flexible moment-resistant structures

− Material limitations: The constraints in selecting specific materials may affect the representativeness of the study for broader real-world applications

− Lack of uniformity: The consistency in controlling variables and test conditions is not always ensured, which may affect the accuracy of the results

− Scale limitations: The scope of the study may not fully reflect the complexity and diversity of real-world applications of flexible moment-resistant structures

− Lack of comprehensiveness: It may not capture all aspects of torsional strength in every operating condition, reducing the comprehensiveness of the study

Despite these limitations, the research team is committed to working sincerely and endeavoring to minimize their impact, while also paying attention to the feasibility and applicability of the results obtained.

Report layout

The content of this report consists of 5 parts:

− Presenting an overview of the research objectives, material selection, and experimental methods

− Presenting the overview of flexible moment mechanism, hardware information, basic knowledge of mold, theory of plastic, and overview torque strength testing machine

− Overview of research on soft structures both domestically and internationally: Assessing research studies, research projects, and advancements in the field of soft structures from both domestic and international perspectives Analyzing trends in research, applications, and the latest developments in this field

− Soft structure selection: Providing a process and criteria for selecting suitable soft structures for specific research or application purposes Considering factors such as flexibility, load-bearing capacity, adaptability, and reproducibility of the soft structure during the selection process

− Product design: Describing the product design process using the selected soft structure This includes identifying requirements, design analysis, prototyping, and simulating the product to ensure feasibility and performance of the final product

− Tool design: Presenting the tool design process or device to support the production or testing process of products using soft structures This includes evaluating technical requirements, selecting appropriate materials, and manufacturing technologies to create efficient and accurate tools

− Summarizing and analyzing experimental results: providing an overview and analysis of the experimental outcomes, offering key insights into the torsional strength of flexible moment-resistant structures with the various plastic materials utilized

− Analyzing and simulating artificial neural networks (ANNs) provide a new perspective on experimental results, offering insights into new variables that

6 experiments have not been able to generalize By utilizing an artificial neural network (ANN) model, researchers can analyze the complex relationships between variables in experimental data and make accurate predictions about variables that are not directly measured

Chapter 5: Conclusion and Future development

The study concludes by providing a final evaluation of the torsional forces exhibited by various types of plastics and drawing conclusions about their torsional behavior

− The tasks completed by the team in the project include:

− Successfully molding prototype products using ABS, PP, PA6, and HDPE plastics

− Researching the mechanism of flexible moments

− Conducting torsional stiffness tests on sample materials

− Comparing the results of torsional stiffness measurements of the samples with different types of materials

− Drawing conclusions and proposing directions for the project's development

− Upon completion of the measurements, the research continued to graph the torsional force data, comparing the results of various plastic types for analysis Consequently, the study concludes by providing a final assessment of the torsional forces of different plastic materials and drawing conclusions about their torsional behavior

THEORETICAL BASIS

Overview of flexible moment mechanism

2.1.1 What is the flexible moment mechanism?

The soft moment structure is a type of mechanism that is capable of converting motion or force through changes in the shape of its structure, without requiring the use of rigid joints or moving parts dynamic Compared with traditional structures, soft moment structures bring many outstanding advantages such as:

Avoid constant deflection, friction and wear: soft moment mechanisms can avoid the harmful effects of constant deflection, friction and wear, common defects in traditional mechanisms

Low cost and compatibility with absorbent media: the manufacturing cost of soft moment structures is often lower than that of traditional structures, and they are also capable of operating in absorbent environments

Motion or force conversion: soft moment structures are capable of converting motion or force through changes in the shape of their structure, providing flexibility in design and application

High precision: because there is no need for rigid joints or moving parts, soft moment mechanisms often have high precision and reliability in operation

Ability to adjust force: some types of soft moment structures are capable of providing a constant reaction force within a certain range of deformation, making it easy and effective to adjust the force [1-3]

The operating principle of mechanism design is based on the use of flexible components to convert motion or force through changes in the shape of their structure itself Below are the basic principles of mechanism design operation [1]:

Flexibility: Mechanism design often includes flexible components such as flexible bars, flexible corners, or other flexible connections These components are capable of flexibly deforming when force or movement is applied

Balance: Mechanism design is often designed so that balance between forces and motion is maintained, ensuring the stability and performance of the mechanism

Mechanical properties: Mechanism design uses mechanical principles such as stiffness, stretch, and working mechanism of flexible components to convert motion or force as required [2]

2.1.3 Main characteristics of flexible moment mechanism

The moment soft structure is not only an improvement in traditional structure design but also brings many unique and superior characteristics Below are some main characteristics of flexible moment mechanism:

• Provides a stable torque despite changing rotational input

• Minimize the need for sensors and controllers by using passive mechanisms Disadvantages:

• Some CTM structures can be complex and difficult to design, especially in ensuring a constant torque over a given range of rotation

• Careful consideration needs to be given to the accuracy and durability of CTM structures, especially in medical or precision engineering applications

Compliant Constant-Force Mechanism (CFM) [3]:

• Provides a constant reaction force within a certain deformation range, helping to achieve effective force regulation

• Reduces the need for sensors and controllers, reducing costs and complexity in design and manufacturing

• Some CFM structures can be large and difficult to adapt to applications with limited space

• It is sometimes difficult to maintain the accuracy and stability of the reaction force over a wide range of deformations

Flexible moment mechanism (Compliant Rotary Positioning Stage) [5]:

• Simple design, easy to construct and assemble

• Provides a stable torque within a certain deformation range

• Reduces production costs and is easily adaptable for many different applications

• High precision is required in the design and manufacturing process to ensure reliability and performance

• Some structures may require a large number of flexible or complex elements, increasing the complexity and cost of the structure

2.1.4 Application of flexible moment mechanism

In this section, our team will introduce applications of soft moment structures (CTJM) in the industrial and medical fields This emphasizes the diversity and flexibility of CTJMs as they are integrated into different systems and devices [5] Industrial and medical applications of moment soft structures

Soft moment structures have demonstrated exceptional potential in many industrial and medical applications, providing unique and effective benefits Below is an overview of the applications of soft moment structures in these fields:

Figure 2.1: Application of CTJM soft structure products [1]

Fig A Robotics and automation: Soft moment structures are often integrated into robots to provide soft and safe interaction with the surrounding environment This makes them ideal for applications in the automation and manufacturing sectors

Fig C Human joint rehabilitation support device: In medicine, soft moment structures can be integrated into devices to support human joint recovery This helps improve recovery and increase mobility for people who have lost mobility

Fig B Mobile assistive devices and robots supporting space people: Moment- shaped soft mechanisms are used in the design of mobile devices and robots supporting space people They can provide secure interoperability and high

11 performance, making them suitable for many applications in confined space environments

Fig B,C Applications in medicine and health care: Soft moment structures have potential in medical devices such as mobility aids, exoskeletons, and basic rehabilitation devices Their versatility can help improve the quality of life of patients and users

Fig D Applications in research and development: Moment soft structures are also widely used in research and development of new technologies Their diversity provides a flexible platform for experimenting and testing new ideas.

Overview of mold

A mold is a tool (device) used to shape a product according to the shaping method, the mold is designed and manufactured to be used for a certain number of cycles, which can be one time or many times [4]

The texture and size of molds designed and fabricated depend on the shape, size, quality and quantity of the product to be created

The mold for manufacturing plastic products is a cluster of many parts assembled together, divided into two main mold parts:

− Cavity part (female mold part, fixed mold part): Attached on the fixed plate of the plastic injection machine

− Core part (male mold part, movable mold part): Attached on the movable plate of the plastic injection machine

In addition, the space between the cavity and the core (the part that creates the product) is filled with molten plastic After that, the plastic is cooled, solidified and then removed from the mold by product picking system or manual operation The resulting product has the shape of a mold lumen

In a set of molds, the concave part will determine the external shape of the product called the mold bed (also known as negative mold, female mold, mortar, cavity), while the protrusion will determine the internal shape of the product called the core (also known as positive mold, male, pestle, core) A set of molds can have one or more lumen and cores The contact between the lumen of the mold and the core is called the mold face

In addition to the core and cavity, there are many other parts in the mold These parts are assembled together to form the basic systems of a set of molds including:

− Guidance and positioning system: Including all guide pins, guide bearings, positioning rings, positioners, gables, There is a task between the correct working position of the two mold parts when joining together to create the correct mold lumen

− Plastic guidance system into the mold lumen: Including injection stem silver, plastic channel and nozzle responsible for supplying plastic from the injection head of the press into the mold inside

− Product propulsion system: Including side core, core cheek, guide bar, oblique pin cam, hydraulic cylinder, Do the task of removing the undercut parts right in the direction of opening the mold

− Air exhaust system: Including air outlet grooves, responsible for bringing out the residual air in the mold lumen, facilitating plastic to fill the mold easily and preventing products from leaking or burning

Cooling system: including water lines, grooves, heat pipes, connectors, is responsible for stabilizing mold temperature and cooling products quickly [4-5]

Figure 2.2: General structure of mold [4]

The double-plate mold is an injection mold using a cold channel system, a channel located across the face of the mold, a plastic entrance gate on the side of the product and when opening the mold, there is only one opening to take the product and the plastic channel

For double-plate molds, the plastic entrance gate can be designed so that the product and plastic channel automatically separate or do not separate when the product and plastic channel (glue bone) are removed from the mold

The method of using two-plate molds is very common in injection molding systems The mold consists of two parts: the front mold (negative mold) and the back mold (positive mold) The mold structure is simple, easy to manufacture, but double- plate molds are usually only used to create products that are easy to arrange plastic entrance gates [5].

Overview of plastic injection molding technology

Figure 2.3: Structure of plastic injection molding machine

− Basic principles of plastic injection molding [6]

The injection molding machine works like a needle First, the plastic (powder or granule) will be put into the hopper Next, the plastic will be melted by the heating rods and turned into liquid At this time, all the liquid plastic will be guided forward by the screw At the same time, the screw will move back to create space for the plastic to flow into the front of the nozzle

Plastic pellets are fed through the funnel into the barrel and heated to a molten state.

Molten plastic part - motorized screw pushes molten plastic into the mold.

The screw injects molten plastic at pressure into the mold cavity through the gate (hot runner).

The plastic product is allowed to cool and solidify before being pushed out of the opened mold.

Figure 2.4: Operating principle of plastic injection machine

Thanks to the pushing pressure of the screw (not rotating), molten plastic will be injected into the mold Once the mold is filled with plastic, the cooling system will convert the plastic from liquid to solid and cool the product The movable mold clamp will open the mold some distance and push the product out

Plastic pellets: the main raw material in the plastic injection molding process is plastic pellets, often produced with specific properties depending on the final application of the product

Modifiers and colors: sometimes, additives such as softeners, UV inhibitors and colorants can be added to the resin to improve the properties of the final product

Melting nozzle: Plastic pellets are fed into the melting machine through the melting nozzle, where they are melted into an easily handled liquid plastic

Thermal control system: Temperature control is an important factor to ensure uniform melting of plastic and achieving the desired product quality

Injection mold: Liquid plastic is put into injection molds according to specified shapes and sizes to create the final product

Pressure system: Plastic pressure is maintained to ensure accurate and efficient injection molding process

− Cooling and product removal process:

Cooling system: After the plastic has been injected into the mold, a rapid cooling process is performed to solidify the product

Product separation: The finished product is removed from the mold, and this process may include steps such as rapid cooling and demoulding

− Quality control and production control:

Control system: automated quality control systems are used to ensure that every product meets quality standards

2.3.2 Application of plastic injection molding technology

Currently, at manufacturing plants, the application of modern plastic injection molding technology helps produce a large number of quality, consistent plastic products without consuming much time and manpower

The products are manufactured and made from hard plastic materials with good electrical and thermal insulating properties, high hardness, and durable in use

Commonly used products from hard plastic include household appliances, office furniture, furniture, plastic machinery, plastic bottles, plastic food containers, water pipes, tables and chairs, and electrical covers phone…

Plastic products are commonly used in the fields of interior decoration, automobile manufacturing, phone accessories

In addition, plastic molding technology creates products used in industries requiring high precision, optical and electronic products

Plastic injection molding technology is used in the production of products in daily life and in the industrial sector such as: safety glasses, helmets, containers, car light covers, and shields thermostat, temperature sensor…

Overview structure of Haitian plastic injection molding system

The Mars (MA II) HAITIAN series is an innovation and upgrade of the Saturn (SA) series with energy saving and environmental protection features The special design of the machine ensures maximum electricity and water savings Along with improving efficiency in the production process, the accuracy of the product also has a clear improvement The Mars (MA) Haitian machine series is an improvement of the traditional hydraulic machine series, which has shortened the gap between traditional machines and electric machines [6]

Name machine: PLASTIC INJECTION MACHINE

Figure 2.5: Haitian MA 1200III plastic injection machine

Overview of experimental plastic materials

PP (Polypropylene) is a hard, tough and crystalline polymer thermoplastic produced from propene (or propylene) monomers Has a transparent white color, colorless, odorless, tasteless, non-toxic [7]

Table 2.1: Basic information of plastic PP

Tensile strength at yield 30 MPa

Modulus of elasticity in tension 1600 MPa

Creep rupture strength after 1000hrs with static load

Figure 2.6: PP plastic pellets Table 2.2: PP (Polypropylene)

- Good waterproofing and chemical resistance

- Impact resistant and not deformed

- Has a high coefficient of thermal expansion which limits high temperature applications

- Has poor resistance to chlorine solvents and aromatics

- Known to be difficult to paint because it has poor bonding properties

- Used as waterproof and permeable membranes for products in the printing industry

- Used as materials in the education industry such as rulers, ballpoint pens or covers for files, books,…

- Used as packaging in the food industry

- Application in the furniture industry such as making plastic boards, vinyl flooring

Figure 2.7: Application of PP plastic

Polyamide PA6 (commonly known as nylon) belongs to the line of engineering polymers (engineering plastics) This type of plastic is mainly used in engineering applications where physical and mechanical properties are required [7]

Table 2.3: Basic information of plastic PA6

Figure 2.8: PA6 plastic pellets Table 2.4: PA6 (Poly Amide 6)

- High hardness and resistance to cracking, impact resistance

- Easy processing, good aesthetic appearance, beautiful bright surface, impact modification, thermal stability, self- extinguishing

- High water absorption ability affects the dimensional stability of the product

- Nylon 6 is unstable in acidic and base environments

- Wind turbine blades, structural control panel, abrasion resistant cushion

- Bearing parts, gears, pump parts, parts in automobile manufacturing

- Sliding rails, belt wheels, connecting pipes,

Figure 2.9: Application of PA6 plastic

HDPE (High Density Polyethylene) is a thermoplastic made from petroleum, high density molecular structure, so it is thick, hard, resistant to impact and stretching better than ordinary PE plastic This is the most commonly used synthetic plastic in production today [7]

Table 2.5: Basic information of plastic HDPE

Figure 2.10: HDPE plastic pellets Table 2.6: HDPE (High Density Polyethylene)

- Safe to use, long-term reliability

- Easy to flex, mold with diverse designs

- High impact resistance, good scratch resistance

- Anti-electrification, toxic chemicals, corrosion resistance

- Lower hardness compared to Polypropylene

- Difficult to bond by weld

- May crack, plastic bonds broken due to sudden temperature changes

- High-density polyethylene is used in packaging in industry and food

- Widely used in civil with low cost

- Thanks to its high tensile strength, HDPE is widely used in rope systems, fishing and sports nets, agricultural nets, industrial and decorative fabrics

- Other applications of HDPE include pipe systems and fittings: drainage pipes, car fuel tanks, wiring & cables - energy panels, telecommunication cables

Figure 2.11: Application of HDPE plastic

ABS plastic has the full name of Acrylonitrin Butadiene Styrene, ABS plastic has the characteristics of hard, solid but not brittle, insulating, waterproof, resistant to temperature and chemicals so does not deform the product [7]

Table 2.7: Basic information of plastic ABS

Figure 2.12: ABS plastic pellets Table 2.8: ABS (Acrylonitrile Butadiene Styrene)

- Easy to damage when exposed to sunlight

- Dangerous and poisonous when burned

- Low water absorption, good wear resistance

- Restrictions in the food industry

- The price is higher than others

- Injection molded ABS plastic is used to make household appliances, electronics, helmets, wall panels for electrical outlets, dashboards, wheel covers and other vehicle parts

- In addition, computer keyboards, phone cases are produced,

Figure 2.13: Application of ABS plastic

Torque strength testing machine

A torque gauge is a device designed to measure movement and manage torsional forces applied to materials, mechanical parts, or other equipment They are commonly used in many large industries, from automobile manufacturing to the

28 aviation and packaging industries The torque meter can measure the maximum torque parameters, the torque varies over time, and the torque accuracy is applied These types of gauges are often used to measure variation or muscle sensors to monitor and measure torsional energy [8]

Figure 2.14: Structure of torsional strength tester machine

Torque sensor: Is a mechanical input transducer that twists into an electrical signal at the output, used to measure and monitor torque in many industrial and research applications Torsion sensors are usually specifically designed to withstand the pressures and torsional forces that objects are under These sensors often use physical principles such as mechanical deformation or changes in resistance to measure torque

Encoder: Is a digital circuit that converts a set of binary inputs into a unique binary code It plays a crucial role in digital systems, converting parallel inputs into serial codes

A PLC (Programmable Logic Controller) is an electronic device used in industrial automation to control and monitor production systems and processes PLCs are often used to perform control functions such as opening and closing valves, motors, sensors and other electrical devices based on a pre-programmed logic program

A motor is a moving device used to convert electrical energy into mechanical motion There are different types of motors used in different applications, but the two most common are AC motors and DC motors

Belts: Also known as belt drives or belts, are a loop of wire made of a flexible material used to mechanically bond two or more axes of rotation, usually moving in parallel The straps are usually looped around the pulleys, which can be parallel or twisted between the pulleys

Three-jaw chuck: Is a type of equipment used in mechanical processing to clamp and center rotating round parts Three-jaw chucks are an important part of mechanical machining, helping to ensure production accuracy and performance [9]

Turn on the circuit breaker that supplies power to the PLC controller and motor The motor makes the shaft fit to 1 side of the rotating chuck, pulling the moving end of the jig and the rotating part and generating torque acting on the torque sensor attached to the other 1 side of the chuck The PLC receives the transmitted signal from the torque sensor and writes the torsion data to the memory on the computer Encoder adopts a belt drive that synchronizes the movement with the spindle of the motor to count the torsion angle data and transmit the signal to the PLC, the PLC receives and records the torsion angle data corresponding to the torsion into the memory on the computer [9]

TIA Portal V17

TIA Portal V17 is an overview solution for the design and development of Siemens automation systems It includes a graphical programming environment and a wide range of tools that support the creation, editing and maintenance of programs for automation devices [10]

- Easy to use interface: The TIA V17 offers an easy-to-use graphical interface, making it easy for users to create and edit programs

- Full integration: Full integration of tools and features needed to design and develop automation systems, including PLC programming, user interface creation, integration of devices and sensors, and data management

- Project management features: TIA Portal V17 provides project management features, helps users track and adjust project progress, and optimizes time and resource management

- Integration with other software: can be integrated with other software such as SCADA and MES, helping users optimize the power and features of the system

- Support for a wide range of devices: TIA Portal V17 supports a wide range of automation equipment, including Siemens PLCs for example the commonly used 6ES7214-1AD23-0XB0 and is well compatible with TIA V17, mid-control devices and connections to sensors and actuators This allows users to integrate devices from many different manufacturers into a single automation system Support for a wide range of devices provides users with flexibility and customization in the design and development of their automation systems [10]

Matlab

MATLAB is one of the leading scientific and technical calculation software in the world, developed by MathWorks With MATLAB, users can perform a variety of calculations, analyze data, and perform programming-related tasks efficiently and flexibly [11]

- Data analysis: with MATLAB, users can perform complex data analysis, including statistical methods, signal processing, and machine learning Built-in tools and functions in MATLAB make it easy for users to perform data analysis tasks

- Graphics and charts: MATLAB provides powerful tools for creating and displaying graphics and charts Users can create 2D charts, using shaping, color, and annotation tools to visualize data clearly [11]

2.8.3 Artificial neuron networks in MATLAB

ANN (Artificial Neural Network) originated from the idea of simulating the human brain Similar to humans, ANN learns from experience, stores those experiences, and utilizes them in appropriate situations Within the ANN toolkit, there are 12 high-performance training functions available To use this toolkit, users need to define the structure including creating an input data matrix (Input Data) and target output data (Target Data), then call the ANN toolkit in a file 'm' to configure and select network parameters In order to achieve the goal of predicting torque moments, the team applied neural networks to assist in predicting results with arbitrary parameters This process involves training the network and creating a neural network block for use in Simulink The first step is to select New Variable → With input, where the input parameters include injection pressure, mold pressure, plastic temperature, mold temperature, molding time, rotation angle, and the target is the torque moment [12]

Origin Pro

Origin Pro is a popular graphical and data analysis software developed by OriginLab Corporation With its user-friendly interface and powerful features, Origin Pro is an indispensable tool for scientists, engineers, and researchers in many engineering fields [13]

- Powerful Data Analysis: Origin Pro offers a diverse range of data analysis tools and methods, including statistics, signal processing, and chemistry Users can perform complex analyses such as regression analysis, variation analysis, and time series analysis

- Charts and graphics: Origin Pro allows users to create and customize charts and graphics with ease Users can create 2D and 3D charts, distribution graphs, contour charts, and radar charts to visualize their data [13]

Inventor

Autodesk Inventor is designed to help engineers, designers and those working in the manufacturing industry create accurate 3D models and technical drawings [14]

- Manufacturing industry: Inventor is widely used in the manufacturing industry to design and develop products from individual parts to complete systems

- Mechanical and basic engineering: mechanical engineers and basic engineering engineers use Inventor to design and develop products, machines, equipment and tools

- Automotive and electronics: in the automotive and electronics sectors, Inventor is used to design and develop elements of cars, electronic devices, mechanical components and other complex systems

- Mechatronics and information technology: in these areas, Inventor is used to design and develop mechatronic components, boards, microchips and related products

- Medical and medical devices: medical device manufacturers use Inventor to develop products such as medical devices, medical instruments, and other necessary medical devices

- Energy and environment: in the field of energy and environment, Inventor is used to design and develop products such as generators, energy-efficient equipment and environmental treatment systems

- Education and research: in an educational and research environment, Inventor provides a powerful tool for teaching and research on engineering and design concepts [14]

DESIGN PRODUCT

Research both domestically and internationally

With the research project of authors Thanh-Vu Phan and Huy-Tuan Pham with the topic Design and Analysis of a Compliant Constant-Torque Mechanism for Rehabilitation Devices shows that in this study, a simple and effective method for designing a flexible CTM has been proposed Shape optimization combined with genetic algorithms was used during the design process Taking full advantage of the flexible mechanism without the need for movable joints, the use of designed equipment will lead to reduced wear, reduced lubrication needs, and increased performance by increasing accuracy The implementability of the mechanism to achieve a stable output torque is confirmed through finite element analysis CTM suggestions can be used for human joint restoration devices or mobility aids for humans The design can be seamlessly manufactured and scaled down for use in other smaller devices

With research topics of two groups of authors Chia-Wen Hou và Chao-Chieh Lan with the topic Functional joint mechanism with constant-torque outputs và Piyu Wang, Sijie Yang và Qingsong Xu with topic Design and Optimization of a New Compliant Rotary Positioning Stage with Constant Output Torque

Through the above 2 research topics, it helps to research the design of the torque soft structure to become more optimal, saving a lot of time for future experimental topics.

Choose soft structure

The design of a constant moment coupling mechanism (CTJM) using a distributed compliance model can be classified into two types [1]: a) The first type is a distributed elastic wing parameterized using five segments

Figure 3.1: Diagram of distributed compliance model (Type I) [1]

This type uses five symmetrically placed segments (ranging in length from L2 to

L6) that enclose the design space in an arc configuration Each segment can bend and stretch, divided into six nodes (n2–n7) The optimization goal is to adjust the values of Tmax and Tmin to create a flat torsion curve and optimize the constant torque region b) The second type is a distributed elastic wing parameterized using three segments (Type II):

Figure 3.2: Diagram of the distributed compliance model (Type II) [1]

It also uses five symmetrical segments (from L2 to L6), but is simplified with two curved segments (L2 and L4) and one straight segment (L3) The optimization goal is to minimize shape variation and optimize flatness of the constant torque region

The choice between type I and type II constant torque joint mechanisms (CTJM) depends on application-specific factors as well as design requirements Below are some important points to consider when determining when to use each type:

Type I (Five-Segment Elastic Wing):

• This type is more complex than Type II because it uses five wing segments

• Type I is suitable when it is necessary to distribute the stiffness and compliance of the mechanism over the entire wing

Type II (Three-Segment Elastic Wing):

• This type is simplified with only three wing segments, minimizing the complexity of the mechanism

• Type II is suitable when you want a simple model with good performance and easy adjustment

Choosing a type I flexible torque mechanism (CTJM) offers many benefits, especially in providing consistent torque and minimizing cost and complexity during design and operation Although there are challenges with accuracy and durability, they can be overcome through a thorough design and manufacturing process

• Consistent torque delivery: Type I CTJM are capable of delivering a constant torque over a given range of rotation, independent of input variations This makes Type I CTJM a suitable choice for applications requiring consistent torque such as in load leveling or vibration reduction

• Minimizes the need for sensors and controllers: Type I CTJM operate passively, meaning there is no need to use complex sensors or controllers to

37 maintain torque This reduces cost and complexity during design, manufacturing and operations

• Complexity in design: Some type I CTJM structures can be complex and difficult to design, especially to ensure a constant torque over a given range of rotation However, this can be reduced through careful design and simulation considerations

• Precision and durability: Careful consideration needs to be given to the precision and durability of CTJM structures, especially in medical or precision engineering applications This requires the design and manufacturing process to reach a high level of precision and quality control

Since the target project is applications requiring flexibility and evenly distributed stiffness, type I is selected.

Design product

Below is the model of the soft structure product, designed with a phi diameter of 90mm and a thickness of 5mm This mechanism has 4 pins with a width of 0.9mm each, which can be changed, capable of bending clockwise The model consists of 4 fixed holes and 1 square hole in the middle with a size of 9mm and a 3mm board angle linked by a spline curve designed on Autodesk Inventor software

EXPERIMENTAL RESULTS

Plastic injection experiment

4.1.1 Injection parameters and experimental products of PP plastic

Figure 4.1: PP plastic injection injection parameters

• Position 1 take 15 plastic, pressure 80, speed 90

4.1.2 Injection parameters and experimental products of PA6 plastic

Forming pressure Shaping time Injection molding

Figure 4.2: Injection parameters of PA6 plastic

4.1.3 Injection parameters and experimental products of HDPE plastic

Figure 4.3: Injection parameters of HDPE plastic

4.1.4 Injection parameters and experimental products of ABS plastic

Figure 4.4: Injection parameters of ABS plastic

Experimental measurement equipment

To perform a torsion test using the torque strength testing machine, the team applied a fixture device to place the product on the torsion gauge

Install into a fixed 3-jaw chuck

Install into a fixed 3-jaw chuck rotates freely

Figure 4.5: Product test jig model

Experimental measurement procedure

Step 1: Prepare product samples of 4 types of pressed plastic and specialized jigs

Step 2: Fix the product to a specialized jig for a torsion moment meter, check the compatibility of the product with the jig

Figure 4.7: Installation of jigs into experimental machines

Step 3: Turn on the dedicated torque meter, open the machine's PLC and connect to the laptop via the LAN wire port to control the machine and receive data directly on the laptop

Figure 4.8: Laptop connection torque and PLC

Step 4: Start the TIA Portal V17 software to run a pre-programmed program to measure torque

Step 5: Set to 0 torsion and torque angles on the measuring software, delete the old data file and create a new file to proceed with the new data collection After completing start to measure and collect torque measurement results

Graph torque moment by rotation angle

Figure 4.9: Moment meter control interface

Step 6: Conduct an experimental process test and get the results.

Experimental measurement

Table 4.1: Injection parameters of 4 types of plastic

Plastic P inj P form T melt T mold t shap

T melt = 220ºC, T mold = 40ºC, t shap = 0s

Figure 4.10: The chart shows the deformation of PP plastic products

In case the torsional rupture angle of the sample falls to approximately 275-300 degrees, the test specimen begins to undergo torsional deformation and then fractures

Case 2 is similar to case 1 The torsional rupture angle of the sample also decreases to around 275-300 degrees, and the test specimen begins to undergo torsional deformation and fracture

In case 3, the torsion rupture angle is shorter, only approximately 250-275 degrees, and the test specimen exhibits torsional deformation and fracture

From the chart above, the study provides an overview of the average torsion fracture angle of PP plastic at about 250 to 300 degrees This indicates that PP plastic often withstands a high degree of torsion before fracturing, and approximately 250 to

300 degrees is the average torsion angle at which this material typically fractures under such experimental conditions

Figure 4.11: The chart shows the deformation of PA6 plastic products

In case the torsional rupture angle of the specimen falls to approximately 300 degrees, the specimen begins torsional deformation and then breaks

In case the torsion angle of rupture of the sample falls to approximately 275-300 degrees, the test sample begins torsional deformation and then breaks

In case 3, the torsion angle of rupture of the sample is similar to case 2, which is approximately 275-300 degrees, then the test sample begins torsional deformation and then breaks

From the chart above, the study provides an overview of the average torsion fracture angle of PA6 plastic at about 275 to 300 degrees This indicates that PA6 plastic often withstands a high degree of torsion before fracture occurs, and about 275 to 300 degrees is the average torsion angle at which this material typically fractures under such experimental conditions

Figure 4.12: The chart shows the deformation of HDPE plastic products

In case the torsional rupture angle of the specimen falls to approximately 250 degrees, the specimen begins torsional deformation and then breaks

Cases 2 and 3 are similar to case 1 The torsional rupture angle of the sample falls to approximately 250 degrees and the sample begins to undergo torsional deformation and then fractures

From the chart above, the study provides an overview of the average torsion fracture angle of HDPE plastic at about 250 degrees This indicates that HDPE plastic typically withstands a moderate degree of torsion before fracture occurs, and around

250 degrees is the average torsion angle at which this material usually fractures under normal experimental conditions

Figure 4.13: The chart shows the deformation of ABS plastic products

In case the torsion angle of rupture of the sample falls to approximately more than 150 degrees, the test sample begins torsional deformation and then breaks

Case 2 is similar to case 1, the torsion break of the sample only falls at approximately 150 degrees and the test sample begins torsional deformation and then breaks

In the case of 3, the torsion angle broke only at approximately 125-150 degrees and the test specimen began torsional deformation and then fractured

From the chart above, the study provides an overview of the average torsion fracture angle of ABS plastic at about 125-150 degrees This indicates that ABS plastic can withstand a fairly low level of torsion before fracture occurs, and approximately 125-150 degrees is the average torsion angle at which this material typically breaks under normal experimental conditions

Based on the above data, the study has generated an experimental synthesis chart of ABS, HDPE, PP, and PA6 plastics

Figure 4.14: The chart shows the average deformation of 4 plastic products

The study shows that, through the chart, PA6 plastic has the highest torsional breaking strength when deformation occurs at a torsional angle of 275-300 degrees, while ABS plastic has the lowest torsional strength, occurring only at a torsion angle of 125-150 degrees Fracture deformation has occurred, while PP and HDPE plastics have the same torsional strength at a torsion angle of 250-300 degrees.

Utilizing ANN_neuron network in MATLAB

After running the ANN on MATLAB, the team obtained the following results:

Figure 4.15: Training result plastic PP

Figure 4.16: Training result plastic PA6

Figure 4.17: Training result plastic HDPE

Figure 4.18: Training result plastic ABS

The study employs neural network simulation method to investigate the torsional behavior of components The neural network model is designed with 1 layer and 12 neurons There are a total of 6 input variables and 1 output variable, including 5 variables related to the plastic injection molding process and 1 variable for torsional angle The output variable is torsional moment

The research utilizes figures from 4.15 to 4.18 and conducts 1000 training iterations The obtained results show an error of less than 0.001; however, this is only a reference result due to remaining limitations in terms of time and technology.

Comparing results

Figure 4.19: ANN simulation results and experiments of PP plastic

Through the analysis of chart 4.19, the study demonstrates that the similarity between the simulation results of the Artificial Neural Network (ANN) and the experimental data is quite high in the range from 0 to 270 degrees However, through observation of the chart, the study indicates a deviation between the simulation results and the experimental results in the range from 280 to 330 degrees

Figure 4.20: ANN simulation results and experiments of PA6 plastic

Through the analysis of chart 4.20, the study indicates that the similarity between the simulation results of the neural network (ANN) and the experimental data is quite high in the range from 0 degrees to approximately 240 degrees However, through observation of the chart, the study points out a deviation between the simulation results and the experimental results in the range of approximately 255-330 degrees Case 3: Plastic HDPE

Figure 4.21: ANN simulation results and experiments of HDPE plastic

Through the analysis of chart 4.21, the study indicates that the similarity between the simulation results of the neural network (ANN) and the experimental data is quite high in the range from 0 degrees to approximately 210 degrees However, through observation of the chart, the study highlights a deviation between the simulation results and the experimental results in the range of approximately 225-270 degrees Case 4: Plastic ABS

Figure 4.22: ANN simulation results and experiments of ABS plastic

Through the analysis of chart 4.22, the study indicates that the similarity between the simulation results of the neural network (ANN) and the experimental data is quite high in the range from 0 degrees to approximately 60 degrees However, through observation of the chart, the study points out a deviation between the simulation results and the experimental results in the range of approximately 60 to 150 degrees

CONCLUSION AND FUTURE DEVELOPMENT

Conclusion

Through the simulated ANN chart and experimental results, the study demonstrates that PA6 plastic is suitable for both industrial and daily life purposes due to its excellent mechanical properties and torsional strength when utilizing the flexible moment mechanisms structure

Through the obtained results, the Flexible Moment Mechanisms structure can be applied in the following fields:

+ Industrial robot: The structure from "Mechanism Design" can be applied in designing the motion mechanism of industrial robots This design reduces production costs, simplifies the structure of the robot and is also suitable for applications requiring rotational motion, such as in automated production or assembly processes

+ Medical devices: Medical applications such as mobility aids, rehabilitation devices, or daily living support devices can use the structure from "Mechanism Design" to design movements that suit the user's needs, while reducing production costs

+ Automotive industry: In automobile manufacturing, mechanisms from "Mechanism Design" can be used to design basic parts such as door opening mechanisms, seat adjustment mechanisms, or rear trunk opening mechanisms Using this structure reduces production costs and increases the reliability of these systems

+ Electronic technology: In electronic products such as scanners, printers, or smart home appliances, mechanisms from "Mechanism Design" can be used to design motion mechanisms such as mechanisms Open the lid, the mechanism automatically adjusts the angle, helping to optimize performance and reduce production costs + Renewable energy technology: In renewable energy applications such as solar tracking systems, mechanisms from "Mechanism Design" can be used to design

61 mechanisms to adjust the direction and tilt angle of the solar panels, helping to optimize energy recovery efficiency and reduce production costs.

Limitations and future development

Since this project falls within the scope of the graduation thesis, and considering thelimitations of both economic resources and time, it inevitably encounters the following constraints:

+ Material limitations: Although product models have been created using various polymer materials, further research on the strength, durability, and abrasion resistance of these materials in real-world environments may be necessary for improvement

+ The ANSYS simulation process is not favorable due to the inadequate design of the flexible mechanism

+ Limitation regarding the sample manufacturing method, which may necessitate a change in manufacturing methods such as 3D printing

With the results achieved, the following development directions are proposed:

+ Further research the impact level when changing different types of materials Continue research on new and innovative materials to improve product quality and properties This may include research into materials that are load-bearing, wear- resistant, and resistant to harsh environmental conditions

+ Performance optimization research: continue to research and develop structures to improve product performance and stability This may include the use of design optimization methods and engineering calculations to increase efficiency

+ Further research the impact level when changing injection molding parameters + Research to increase flexibility: develop variations or expanded versions of Mechanism Design soft structures to provide greater flexibility and the ability to

62 diversify applications Consider integrating these soft mechanisms into multifunctional systems or high-precision applications

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Tiêu đề	Study on the Durability of Flexible Moment Mechanisms with Various Types of Plastic Materials
Tác giả	Pham Cong Thuan, Tran Thanh Danh, Tang Thai Khang
Người hướng dẫn	Assoc. Prof. Dr. Do Thanh Trung
Trường học	Ho Chi Minh City University of Technology and Education
Chuyên ngành	Mechanical Engineering Technology
Thể loại	Graduation Thesis
Năm xuất bản	2024
Thành phố	Ho Chi Minh City

Định dạng
Số trang	87
Dung lượng	6,5 MB