(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system

(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system(Đồ án tốt nghiệp) Research and improvement of a heating oven for molds in liquid plastic tags manufacturing with scada system

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION

FACULTY FOR HIGH QUALITY TRAINING

GRADUATION PROJECT

Major: MECHATRONIC ENGINEERING

Advisor: PHAM BACH DUONG, PhD.

Ho Chi Minh City, August 2020

RESEARCH AND IMPROVEMENT OF A HEATING OVEN FOR MOLDS IN LIQUID PLASTIC TAGS

MANUFACTURING WITH SCADA SYSTEM

INDEX

LIST OF FIGURES: 1

LIST OF TABLES: 3

ACKNOWLEDGEMENT 4

ABSTRACT 6

CHAPTER 1: INTRODUCTION 7

1.1Introduction 7

1.2 Manufacturing process of Plastic tag products 7

1.3Subject and scope 8

1.3.1 Research subjects 8

1.3.2 Scope of the study 9

1.4 Improvement methodology 9

CHAPTER 2: LITERATURE REVIEW 10

2.1Concept and definition about heating ovens 10

2.1.1 Definition of heating oven 10

2.1.2 Introduction to electric oven 10

2.2Industrial oven: 11

2.2.1 Types of Industrial Oven: 11

2.2.2 Commercially available industrial ovens 12

2.3Thermal concepts and principles 14

2.3.1 Heat energy 14

2.3.2 The rocess of heat gain and exothermic 15

2.4 PI control temperature: 18

2.5 Methods for determining the parameters of a PI controller: 20

2.5.1 Manual adjustment method 20

2.5.2 Determining parameters for PI controller by experimental method (the second method of Ziegler - Nichols) 21

2.5.3 Method Chien - Hrones - Reswick (CHR) 21

2.5.4 Cohen - Coon method 22

2.5.5 Method Wang - Juang - Chan (WJC) 23

2.5.6 Tyreus – Luyben Method: 24

2.6Select controller design method 24

CHAPTER 3: DESIGN AND IMPROVEMENT 26

3.1Mechanical design: 26

3.1.1 Calculation and selecting components: 26

3.2.2 Implementation: 56

3.2Electrical design: 59

3.2.1 Block diagram of Heating system: 59

3.2.2 Operational description: 60

3.2.3 Schematic: 60

3.2.4 Diagram of Circuit: 63

3.3Control Design: 64

 Control’s target 64

3.4SCADA system 70

3.4.1 HMI 70

3.4.2 Factory IO 71

3.5Set up parameters for PI controller: 71

3.5.1 System definition: 71

3.5.2 Determine PI controller parameters by Ziegler-Nichols 1 method (for Right oven): 74 3.5.3 Determine PI controller parameters by Ziegler-Nichols 2 method (for Right oven): 76 3.5.4 Determine the PI controller parameters by using Matlab (for Right oven): 78

3.5.5 Determine the PI controller parameters for Left oven: 81

3.5.6 Apply the PI controller to the real system: 84

CHAPTER 4: EXPERIMENTS AND ANALYSIS 86

4.1 Design experiments: 86

4.1.1 List of needs: 86

4.1.2 List of metrics: 87

4.1.3 Needs Metrics Correlation Matrix: 88

4.1.4 Product Specification: 89

4.1.5 Methods of Experiment: 91

4.2Operation experiments: 93

4.2.1 Static test: 93

4.2.2 Dynamic test: 94

4.3 Analysis: 99

4.3.1 Static test analysis: 99

4.3.2 Dynamic test Analysis: 100

100

CHAPTER 5: CONCLUSION & DEVELOPMENT 102

5.1Conclusion: 102

5.2Future work: 103

References 104

LIST OF FIGURES:

Figure 1: Manufactory process of plastic tag 7

Figure 2: Promotional two layers PVC baking oven [9] 12

Figure 3: Energy-saving PVC baking oven [10] 13

Figure 4: The process of cooling and baking 16

Figure 5: Response of PV to step change of SP vs time for Kp 19

Figure 6: Response of PV to step change of SP vs time for Ki 20

Figure 7: Response of the system to Ziegler-Nichols method [4] 21

Figure 8: Response of the system when adjusting Cohen-Coon [4] 23

Figure 9: System response to the Wang-Juang-Chan method [4] 24

Figure 10: Properties of plastic material 27

Figure 11: Maysor coil [11] 28

Figure 12: LOGO! 12-24 RCE siemens 6ed1052-1md00-0ba8 [13] 30

Figure 13: PT100 M6 screw thermocouple temperature sensor [14] 31

Figure 14: Temperature transmitter coil [15] 32

Figure 15: HMI screen 32

Figure 16: Expansion module for LOGO! 34

Figure 17: Analog output modules 34

Figure 18: Cylinder 35

Figure 19: Galvanized steel box [16] 36

Figure 20: Corrugated iron 37

Figure 21: Stainless steel 37

Figure 22: Aluminum 38

Figure 23: Cooling system by air [17] 38

Figure 24: Cooling system by water (using radiator) [17] 39

Figure 25: Cooling system combine cooling table and water [18] 39

Figure 26: Plumbing structure 41

Figure 27: Diaper calculation of water tank 42

Figure 28: Detail calculation diagram of the radiator 43

Figure 29: Diaper calculation of the radiator 43

Figure 30: Draft drawing 50

Figure 31: Base drawing 51

Figure 32: Left oven cover drawing 52

Figure 33: Right oven cover drawing 53

Figure 34: Water tray drawing 54

Figure 35: Overall drawing 55

Figure 36: 3D simulation 56

Figure 37: Implementation process 56

Figure 38: Overall view of the machine 57

Figure 39: The oven door 59

Figure 40: Block diagram 59

Figure 41: Power supply diagram 60

Figure 42: Oven temperature control cluster 61

Figure 43: Cylinder control cluster 62

Figure 44: Cooler cluster 63

Figure 45: Circuit wiring digram 63

Figure 46: Cylinder step diagram 64

Figure 47: Structure simulation of the furnace 65

Figure 48: Flow chart of control design 66

Figure 49: Heat control diagram 67

Figure 50: Working principle of the cooling system 68

Figure 51: Control panel 69

Figure 52: The SCADA system is displayed on HMI screen 70

Figure 53: Use Factory IO to simulation machine 71

Figure 54: System response chart, experiment, Right oven 72

Figure 55: System response chart, experiment, left oven 72

Figure 56: Accurate characteristic, Approximate characteristic [7] 73

Figure 57: System response chart with Z-N-1 75

Figure 58: System response chart with Z-N-2 75

Figure 59: The system’s oscillation response chart of right oven 76

Figure 60: Chart the system’s response with K=41, T=77 77

Figure 61: Chart the system’s response with K=41, T=667 77

Figure 62: The system’s response chart with K=21,t=67 78

Figure 63: The system’s response chart with K=20.5, T=667 78

Figure 64: Measured and simulated model output 79

Figure 65: Transfer function of right oven 79

Figure 66: Right oven system response chart, matlab 80

Figure 67: Diagram of the system 80

Figure 68: Right oven response chart using PI algorithm 80

Figure 69: System response chart with Z-N-1 82

Figure 70: Measured and simulated model output 83

Figure 71: Right oven response system chart, matlab 83

Figure 72: Diagram of the system 84

Figure 73: System response chart in experiment with PI controller right oven 84

Figure 74: System response chart in experiment with PI controller of left oven 85

Figure 75: Temperature of left oven (℃) 95

Figure 76: Temperature of right oven (℃) 95

Figure 77: Testing time to set baking time (s) 97

Figure 78: Locations of sensors- upper oven 98

Figure 79: Locations of sensors-lower oven 98

Figure 80: Heating process on water 100

Figure 81: Cooling testing 100

LIST OF TABLES:

Table 1: Mission statement 5

Table 2: Specific capacities of some substances 15

Table 3: Determining parameters for PID controller Ziegler-Nichols method 21

Table 4: Select controller according to CHR method 22

Table 5: The PID set parameter according to CHR method 22

Table 6: Control parameter of Cohen-Coon method 23

Table 7: Control parameter of Tyreus-Luyben method 24

Table 8: Specific heat of aluminum mold 26

Table 9: Conductor value [12] 30

Table 10: Thermal conductivity 36

Table 11: PI controller parameter by Ziegler-Nichols method 1 74

Table 12: List of needs 86

Table 13: List of metrics 87

Table 14: Correlation matrix 88

Table 15: Specification 90

Table 16: Method of experiment 92

Table 17: 1-time sampling specification data collection 92

Table 18: Controlling machine mechanical test data 93

Table 19: Electrical components test data 94

Table 20: Transporting time in 6 km (min) 94

Table 21: Experiment to discover the optimum timing 96

Table 22: Experiment to discover the optimum timing 97

Table 23: Testing time to maintenance (hour) 97

Table 24: Table determine where the optimum temperature sensor should be placed 97

Table 25: Table determine where the optimum temperature sensor should be placed 98

Table 26: 1-time sampling specification result and comment 99

Table 27: Overall 102

ACKNOWLEDGEMENT

Our team would like to thank the Ho Chi Minh City University of Technology and Education's Management Board and teachers Throughout the years, the instructors of Mechanical Engineering, Mechatronics in particular, have been devoted to teaching and imparting important information and expertise to us

We would especially want to thank Mr Pham Bach Duong for his committed assistance, straight counsel, and direction throughout the project-making process We continually gain more relevant information while improving the project, but we also learn the spirit of work, the attitude of serious and successful scientific study, and these are extremely important things for We are in the process of learning

We also sincerely appreciate THACH GIA CO., LTD (where the product is operated) for allowing us to borrow the equipment for research and development

In the process of completing the project as well as making a project report, it is difficult to avoid errors, we eagerly await your comments and recommendations so that we may gain more experience and develop our project in the best way possible

We sincerely thank you!

RESEARCH, IMPROVE AND MANUFACTURE OF THERMAL OVEN MOLDING

PLASTIC TAG PRODUCTS

Mission statement:

furnaces for liquid plastic-label products

Product Description Heating oven is used in small and medium-sized

companies, enterprises with the number of workers about

5-7 people

Main business goals Provide heating furnaces for companies, enterprises

need to use Producing the first heating product with Vietnamese brand Minimize competitive costs with machine brands from other countries

ALIBABA

Weibo, Zalo, Zing me,

constraints

Create products with low cost, suitable productivity, easy to repair, suitable for processing workshops to distribute to garment companies,

control circuit systems, etc.), Assembly and processing workshops, service marketing groups, buyers and users, distributors and agents physical

Table 1: Mission statement

ABSTRACT

Plastic manufacturing sector is a strong development trend in today's industrialized society, and it plays an essential part in human existence Although plastic has detrimental impacts on the environment and humans, we cannot ignore the numerous advantages it provides As a result, the plastics manufacturing sector, particularly the manufacture of liquid plastic logos and cards, is quickly expanding

These items are frequently used as key chains, shoe tags, emblems, and souvenir presents Not only that, but it also manufactures protective equipment such as gloves, helmets, and so on

Heating is a crucial stage in the manufacture of a plastic product It aids in the transformation of plastic from liquid to solid As a result, we research and improve a heating oven With characteristics such as compactness, ease of transportation, high efficiency, and cheap cost, we will strive to create the best machine, therefore making the plastic production line more effective

Our country is growing in terms of modernisation and industrialisation People's lives are becoming increasingly better As a result, energy plays a role important Energy

is used in a variety of ways, including the quantity of heat needed for heating, drying, and heat treatment It is critical to utilise this energy source effectively and efficiently Provides high efficiency and significant advantages to consumers as well as the entire land water system in general Electric ovens are frequently utilized in industry to satisfy a variety of practical purposes Thermal energy is used in business and everyday life Play a very vital function Drying may be heated using heat energy As a result, the logical and effective utilization of energy resources is critical Because of the answer to many practical needs, electric resistance furnaces are widely employed in industry

CHAPTER 1: INTRODUCTION

1.1 Introduction

Nowadays, the application of plastic stamps to serve in industries such as garments, shoes of brands is extremely rich that can be attached to many types of products that wrongly promote brands and makeup for more beautiful products A number of lines of flexible rubber labels are listed as follows:

- Stamps of flexible rubber rubbers used to make brand identity logos

- Stamps of plastic rubber labels used as key chains

- Stamps of plastic rubber labels used in fashion and apparel industry

- Stamps of plastic rubber labels for making household appliances labels

- Stamps of plastic rubber labels make the team of interior labels

- Stamps of plastic rubber labels for making briefcases, suitcases and bags

- Stamps of plastic rubber labels for making footwear labels

The market for plastic labeling machines has been largely dominated by China and the prices of Chinese products are quite high The potential of quality Vietnamese products and more reasonable prices is huge Major brands of the world are increasingly concentrated in Vietnam and their need to use labels is very large, which makes the plastic stamp market in greater demand than ever

Therefore, a series of machines bearing the Vietnamese brand name are extremely necessary, they will make it easier for manufacturers to invest in producing plastic labels The research, manufacture and manufacture of one or several types of machines in the plastic label production process is necessary and practical

1.2 Manufacturing process of Plastic tag products

Blending ingredients

Dripping raw material

Vacuum raw material

Heating, Cooling

Taking out of mold, classifying

`

Greatly affecting the production efficiency

Figure 1: Manufactory process of plastic tag

The process of dripping raw material into the mold will determine if the product will achieve the level of clarity and correct shape of the mold or not

Meanwhile, the process of Heating & Cooling the mold after Dripping affects the physical properties of the finished product as well as the desired quality of the finished product, which affects all the products in the mold simultaneously Therefore, the manufacturing process necessarily needs a Heater and Cooler system that meets the above requirements for accuracy and stability for heating oven, built-in thermostats that control temperature and time will make products better, waste less and more energy-efficient From there we have the idea to design and create a heating furnace as above

For heating oven, built-in thermostats that control temperature and time will make products better, waste less and more energy-efficient From there we have the idea to design and create a heating furnace as above effective and efficient use of this energy source is essential

Delivers high efficiency and great benefits to users as well as to the whole land water

in general Electric ovens are widely used in industry to meet many practical needs are in place In practical industry and everyday life, thermal energy plays a very important role Heat energy can be used to heat, dry

Therefore, the rational and effective use of energy resources is very necessary Electric resistance furnace is widely used in industry because of the response many practical requirements are posed

The objective of the project is to apply the product design and development process to:

- Market survey of product needs: find out about existing products, evaluate the potential of products, survey prices, functions and models of products from the market

- Heating furnace design: analyzing customer needs, applying product design process

to perform product shaping steps, drawing detailed drawings, prototyping and processing samples

- Product development: experiment with equipment, conduct product innovations and upgrades, and test market reality

1.3 Subject and scope

1.3.1 Research subjects

- Research, design, and improvement techniques for controlling cooling systems

- Modify the operation of the machine

- Research and design a SCADA system for the heating machine

1.3.2 Scope of the study

Because the machine still not have basis of the experiment for running in industry Beside that, a lot of function of the machine need to be improved follow the need of THACH GIA CO, especially, a SCADA system is necessary for the machine

Specific supports:

- A heating machine

Requirements:

- Verify the PI Algorithm for temperature control

- Find the time and temperature that suitable for the product and mold

- Improve the cooler control method with the threshold voltage

- Design a SCADA system for the machine

- Analyzing and summarizing experience: analyzing and summarizing to assess the demand and ability of the product Analysis to find out the limitations and love disadvantages of the device to improve and perfect development

- Experimental method: product experiment to assess the ability of the product to meet the real needs of the market Experiment to see results, combine analysis to find ways to improve equipment

- Method of experts: consulting instructors, teachers, friends, contacts, using a regular drill to consult, solutions to contribute to the complete equipment

CHAPTER 2: LITERATURE REVIEW

2.1 Concept and definition about heating ovens

2.1.1 Definition of heating oven

An oven is a thermally insulated chamber used for the heating, baking, or drying of a substance, and most commonly used for cooking Kilns and furnaces are special-purpose ovens used in pottery and metalworking, respectively Outside the culinary world, ovens are used for a number of purposes

A furnace can be used either to provide heat to a building or used to melt substances such as glass or metal for further processing A blast furnace is a particular type of furnace generally associated with metal smelting (particularly steel manufacture) using refined coke or similar hot-burning substance as a fuel, with air pumped in under pressure

to increase the temperature of the fire A blacksmith uses a temporarily blown furnace, the smith's heart to heat iron to a glowing red to yellow temperature

A kiln is high-temperature oven used in wood, ceramics and cement manufacturing to convert mineral feedstock (in the form of clay or calcium or aluminum rocks) into a glassier, more solid form In the case of ceramic kilns, a shaped clay object is the final result, while cement kilns produce a substance called clinker that is crushed to make the final cement product (Certain types of drying ovens used in food manufacture, especially those used in malting, are also referred to as kilns.)

An autoclave is an oven-like device with features similar to a pressure cooker that allows the heating of aqueous solutions to higher temperatures than water's boiling point

in order to sterilize the contents of the autoclave

Industrial ovens are similar to their culinary equivalents and are used for a number of different applications that do not require the high temperature of a kiln or furnace

2.1.2 Introduction to electric oven

Define:

An electric oven is a device that converts electricity into heat used in appliances Various technological processes such as: calcining or smelting materials, needles types and other alloys

Electric ovens are widely used in many different fields such as:

In the field of metallurgical engineering and machine manufacturing:

- Producing high quality steel

- Producing Phero alloys

- Specialized training and heat treatment

- Burn items before rolling, forging, stamping and spinning

- Producing castings and metal powders

In other industrial sectors:

- In light industry and food: Electric ovens are used for drying and plating products and item preparation

- In chemical technology: Electric furnaces are used to produce objects

- Glass, ceramics, refractory materials

Electric Ovens are not only present in industries but also this is more and more commonly used in daily life of people in a rich and diverse manner: Electric cookers, electric rice cookers, and water heaters electric water, solid burning equipment, drying

2.2 Industrial oven:

2.2.1 Types of Industrial Oven:

There are two main configurations of industrial ovens, batch and continuous

- A batch oven is also known as a ‘walk-in’ oven These ovens work by inserting batches of materials that all need to undergo the same heat treatment process at different times Batch ovens are also useful if the material to be heat-treated needs

to be changed in different batches The batches are placed into the industrial oven

on carts, trays, or racks, and this can be done either manually or automatically, making it easy to switch between batches

- A continuous oven is often chosen over a batch oven in mass-production settings They provide a consistent heating environment, and often have separate heating and cooling chambers which help to speed-up the process

Industrial Oven Heat Sources:

- The most common heat sources for an industrial oven are hot water, gas, and electricity, and these heat sources are often introduced into the oven via forced convection

Out of the heat sources mentioned above, electric heated industrial ovens are the most popular as they are designed to have extremely fast heat-up times and have a long life span Generally, these industrial ovens are inexpensive, and they don’t result in any pollution

2.2.2 Commercially available industrial ovens

a.Promotional two layers PVC Baking Oven

The upper layer is to bake the logo color, the under layer is to bake the base color

Figure 2: Promotional two layers PVC baking oven [9]

Features:

- Stainless steel material: easy to clean

- Intelligent two layers construction: The speed of two layers can be adjusted separately

- Equipped with automatic pushing equipment, can avoid manual mistake and burn

Defects:

- Due to the open design, it causes heat loss to the environment, wastes electricity, makes the working environment always at a relatively high temperature, uncomfortable for production workers

- Make noise during operation due to the conveyor belt being made of chain

- Large size, takes up a lot of space

Application

The PVC label machine can be used to make various PVC/silicon products: Photo frame/ key chain /luggage tag /key covers / lighter covers/mouse mat/ hair clip/ brooch/ mugs/ refrogeratory magnets/ coasters/ bar mat/ table mat/bottle opener/ antislip mat/ door card/ USB flash disk cover/ card reader cover/ mobile phone straps / mobile phone holder/mobile cleaner/ mobilephone cover/ file cla

mp/ pen container etc

b Energy-saving PVC baking oven

Figure 3: Energy-saving PVC baking oven [10]

Features:

- High fever power, rapid warming

- Under the heating plate configuration 3 pieces of 220V / 2KW heating element, the heating zone configuration 6 220V / 600W heating tube, the total heating power reached 9.6KW, from 20 degrees C to 300 degrees Celsius less than 10 minutes

- Insulation effect is good, reduce energy consumption

- The upper part of the oven is insulated with cotton insulation, the lower part is insulated with a thermal insulation board to improve the thermal insulation effect and reduce the heat loss so as to reduce the energy consumption

- Optimize the cooling water circulation process to improve the cooling rate while avoiding splashing water

When the fabric is baked, the water level in the sink is lower When the finished product is released, the mold will not hit the water surface and no water will splash into the mold Until the mold completely fall in the stainless steel bar, the water level will rapidly rise, contact the bottom of the mold, so as to quickly cool the mold And the water level rose to a certain extent will no longer rise, to avoid submerging the mold

2.3 Thermal concepts and principles

2.3.1 Heat energy

a Heat

Heat is energy transferred spontaneously from a hotter to a colder system or body Heat is energy in transfer, not a property of any one system, or 'contained' within it On the other hand, internal energy is a property of a system

The heat that an object adds or loses during heat transfer is called heat

Calorific is denoted: Q unit of calorimeter J

b Thermal energy

and it is this kinetic motion that is the source and the effect of the transfer of heat across a system's boundary For this reason, the term "thermal energy" is sometimes used

Principle of heat transfer

During heat transfer:

- Heat transfer from high temperature objects to low temperature objects

- The process of heat transfer until the temperature of the objects is equal, then reused

- Total heat output is equal to the total heat energy collected:

Qradition = Qin

2.3.2 The rocess of heat gain and exothermic

Heat gained to heat up objects:

The formula for calculating the heat gain of an object:

𝑄𝑡𝑣 = 𝑚 𝑐 ∆𝑡

𝑄𝑡𝑣: Heat collected for heating objects (J)

M: Weight of object (kg)

c: Specific heat of substance (J / kg.K)

Specific heat is the amount of heat needed to transfer 1 kg of material to increase

Freezing heat is the amount of heat released when 1 kg of a substance changes from a liquid

to a solid Freezing heat is as valuable as molten heat This means that the amount of heat

a substance needs to collect, when it is frozen, it gives off that heat

Note:

- A substance only solidifies when it is at the freezing temperature

- During Cooling, the temperature of the object does not change (at the freezing temperature)

- Cooling point is also the melting point

The process of Cooling and baking can be described as follows:

Figure 4: The process of cooling and baking

b Basic structure of heating oven

General structure of electric ovens:

Conventional electric Ovens consist of three main parts: the furnace shell, the lining, the thermostat

c Oven shell

The electric Oven shell is a rigid frame, mainly to bear the process load

Do furnace work On the other hand, the furnace shell is also used to keep the insulation loose and secure full or absolute tightness of the furnace

For furnaces working with protective gas it is necessary to completely enclose the housing, For normal resistance furnaces, the tightness of the furnace shell only reduces damage heat loss and avoid the inclusion of cold air into the oven especially according to height oven

In particular cases, the resistance furnace can make the shell uncoated private

The frame of the furnace shell needs to be strong enough to withstand the load of the furnace lining and load (calcined material) and mechanical devices mounted on the furnace shell round furnace shells used in gongs and a few ovens rectangular oven casing is used

in chamber Ovens, continuous Ovens, vibrating bottom Ovens round bearing shells are more effective inside the element than rectangular ones when blunt an amount of metal is made in the furnace shell

When constructing the round furnace shell, people often use thick steel plates:

- About 3 to 6 mm when the diameter of the furnace shell is from 1000 to 2000 mm

- About 8 to 12 mm when the diameter of the furnace shell is from 2500 to 4000 mm

- About 14 to 20 mm when the diameter of the furnace shell is from 4500 to 6500

mm

When necessary to increase the hardness of the round shell people use the ring gasket increased by shape steel The rectangular furnace shell is constructed using U, L, and steel plates according to the proper shape The shell may be sealed, may not depend on it closed sealed requirements of the furnace The main method of processing furnace shells is welding and canopy

The refractories section must meet the following requirements:

- Withstand the maximum working temperature of the furnace

- Has enough heat endurance when working

- There is enough mechanical strength when lining materials and placing transport equipment in working condition

- Ensuring the ability to attach a durable and strong wire

- Sufficient chemical stability when working, withstand the effects of the atmosphere oven and the effect of the burning material

- Ensuring minimum thermal capacity, this is especially important for cycle working oven

The insulation is usually in the middle of the furnace shell with the refractory part The main purpose of this section is to reduce heat loss during work job For the bottom, the insulating section requires the most mechanical strength There are other parts that are generally not required

Basic requirements of the insulation:

- Minimum thermal conductivity

- Insulation capacity max

- Stable in terms of physical and thermal properties under specified working conditions The insulation may be constructed of insulating bricks or may be filled in insulation powder

e Heat tray:

Basic requirements of heating plate materials

The heating tray is a heating element of the furnace, working under conditions harsh so requires the following requirements:

- Good heat resistance, not oxidized in an air environment with high temperature

- Must have high mechanical strength, not deformed at working temperature

- High durability requirements

2.4 PI control temperature:

a What is a PI Temperature Controller?

PID temperature control is a loop control feature found on most process controllers to improve the accuracy of the process PI temperature controllers work using a formula to calculate the difference between the desired temperature setpoint and current process temperature, then predicts how much power to use in subsequent process cycles to ensure the process temperature remains as close to the setpoint as possible by eliminating the impact of process environment changes

PI temperature controllers differ from On/Off temperature controllers where 100% power is applied until the setpoint is reached, at which point the power is cut to 0% until the process temperature again falls below the setpoint This leads to regular overshoots and lag which can affect the overall quality of the product

Temperature controllers with PI are more effective at dealing with process disturbances, which can be something as seemingly innocuous as opening an oven door, but the change

in temperature can then have an impact on the quality of the final product If the PI temperature controller is tuned properly it will compensate for the disturbance and bring the process temperature back to the setpoint, but reduce power as temperature approaches the setpoint so that it doesn’t overshoot and risk damaging the product with too much heat

c The P& I Fundamental:

Proportional term (P)

The proportional term produces an output value that is proportional to the current error

value The proportional response can be adjusted by multiplying the error by a constant Kp, called the proportional gain constant

The proportional term is given by

Pout = Kp.e(t)

Where:

Pout: output value in proportional term,

Kp: the proportional gain constant,

e(t) = SP – PV(t): the error (SP is the setpoint, and PV(t) is the process variable)

Figure 5: Response of PV to step change of SP vs time for Kp

A high proportional gain results in a large change in the output for a given change in the error If the proportional gain is too high, the system can become unstable In contrast,

a small gain results in a small output response to a large input error, and a less responsive

or less sensitive controller If the proportional gain is too low, the control action may be too small when responding to system disturbances Tuning theory and industrial practice indicate that the proportional term should contribute the bulk of the output change

Integral term (I)

The contribution from the integral term is proportional to both the magnitude of the error and the duration of the error The integral in a PI controller is the sum of the instantaneous error over time and gives the accumulated offset that should have been

corrected previously The accumulated error is then multiplied by the integral gain (Ki) and added to the controller output

The integral term is given by

𝐼out= 𝐾𝑖 ∫0𝑡 𝑒(𝜏) 𝑑𝜏 = 1

𝑇𝑖∫0𝑡 𝑒(𝜏) 𝑑𝜏 Where:

𝐼out : output value in integral term,

𝐾𝐼 : the integral gain constant,

e(t) = SP – PV(t): the error

Figure 6: Response of PV to step change of SP vs time for Ki

The integral term accelerates the movement of the process towards setpoint and eliminates the residual steady-state error that occurs with a pure proportional controller However, since the integral term responds to accumulated errors from the past, it can cause the present value to overshoot the setpoint value

- Advantages: Integrator eliminates residual deviations of the system, less affected effects of high frequency interference

- Disadvantages: The controller has low effect, so the stability of the system is poor

General analysis: Based on the assessment of advantages and disadvantages of controller types, special attention is given to the fact that controller I is slow-acting, so system stability is poor, and should be accompanied by P into a PI controller; and another factor is the case when the system uses the controller with the differential rule of D term, the system is susceptible to high frequency interference, this type of noise usually exists in industry Therefore, we decided to choose the option of using PI controller for the heating system

2.5 Methods for determining the parameters of a PI controller:

2.5.1 Manual adjustment method

Set KI, KD = 0

Increase KP until the system oscillates circulating

Set the integral time by the oscillation cycle

Adjust the KP value accordingly

If there is a fluctuation, adjust the value of KD

Advantages: no need to know math, use online methods

Disadvantages: requires experienced implementers

2.5.2 Determining parameters for PI controller by experimental method (the second method of Ziegler - Nichols)

Set KI, KD = 0

Increase KP until the system oscillates circulating

Put this KP with Kcrit

Measure the oscillation period set to Tcrit

K crit T crit /8

Table 3: Determining parameters for PID controller Ziegler-Nichols method

Figure 7: Response of the system to Ziegler-Nichols method [4]

2.5.3 Method Chien - Hrones - Reswick (CHR)

Transfer function of the object to be controlled:

The CHR method is also the method used to adjust the parameter of the controller in industry This method is based on system time parameter with hiccup response Chien - Hrones - Reswick offers a variety of system controller choices depending on the R parameter, as shown in Table

Control type

Table 4: Select controller according to CHR method

This method is often used when:

- Functional characteristic lines conveying an air-conditioned closed system

- Functional trajectories conveying closed systems oscillate with a leap of about 20%

Table 5: The PID set parameter according to CHR method

2.5.4 Cohen - Coon method

A design method based on a number of typical system responses, providing estimation capabilities to calculate system parameters Different control systems can be designed by using the following Table 6 directly:

Table 6: Control parameter of Cohen-Coon method

Here, it can be seen that the special feature of the Cohen - Coon method is allowed Select the calibration parameters for the PD stitch

Figure 8: Response of the system when adjusting Cohen-Coon [4]

2.5.5 Method Wang - Juang - Chan (WJC)

Based on the optimal ITAE (Integral of Time miltiply by Absolute Error) standard, the control algorithm proposed by Wang - Juang - Chan is a simple and effective method of selecting coefficients for a PID controller If K, T1, T2 are known, the coefficients of the controller shall be determined as follows:

Figure 9: System response to the Wang-Juang-Chan method[4]

It is easy to see that with this correction method, the overshoot of the response is zero Thus, depending on the requirements of the real system, this method is chosen to respond without overshoot

2.5.6 Tyreus – Luyben Method:

The Tyreus - Luyben method was developed from the Ziegler – Nichols 2 method, reducing the amplification factor, increasing the differential time and integration time with

the control parameters shown in Table 2.5

- KU: critical amplification factor

- TU: oscillation cycle is critical

2.6 Select controller design method

There are many methods to choose parameters for PID controller, in which Ziegler - Nichols method is commonly used for P, PI and PID controllers, this method is simple and

easy to use The method is based on the transient characteristic of the process obtained from experiment with step change value and the object applied to this method are processes with inertial characteristics with relatively small time delay From the above advantages, the author chooses this method which is often used to reduce system disturbances

CHAPTER 3: DESIGN AND IMPROVEMENT

3.1 Mechanical design:

3.1.1 Calculation and selecting components:

a Calculation and selecting components for heating system:

The mechanical design of the machine qualified, so the mechanical part does not need to improve

Requirements on the working ability of the furnace set by the enterprise are:

● Left oven: temperature 250-300, yield 8 minutes / product

● Right oven: temperature 200-250, yield 2 minutes / product

● The volume of each mold is 530 grams, each mold contains 16 products, volume of each product is 2,5 grams

Mold’s intake heat:

Figure 10: Properties of plastic material

The plastic used is Unplasticized Polivinylchloride, so it has a specific heat of cpvc = 1.3 kJ

The capacity of each furnace in operation

- The radiant heat of each mold of the right oven:

𝑄𝑡.𝑟𝑖𝑔ℎ𝑡 = 𝑚𝑚𝑜𝑙𝑑 𝑐 ∆𝑡𝑟𝑖𝑔ℎ𝑡 = 0,55.880.(300-40) = 125,84 (KJ)

- The radiant heat of each mold of the left oven:

𝑄𝑡.𝑙𝑒𝑓𝑡 = 𝑚𝑚𝑜𝑙𝑑 𝑐 ∆𝑡𝑙𝑒𝑓𝑡=0,55.880.(260-40) =106,48 (KJ)

- The baking time of the left oven is 10 minutes, the baking time of the right oven is

4 minutes, we have the cooling system heat for 1 hour:

𝑄𝑜𝑣𝑒𝑛.1 ℎ𝑜𝑢𝑟 =60

8 125,84 +60

2 106,48= 4138.2(KJ) Calculation of equipment for electricity systems:

- The capacity of the two furnaces in operation is:

Consider more convenience factors from the objects available in the market: compact, large enough, equipped with good insulation between the wire and the surrounding environment, support available for installation, We decided to choose the Mayso heater wire heaters available in the market, with a maximum capacity of 1.8KW

❖ Wire burning resistance: Mayso heat coil

Figure 11: Maysor coil [11]

Technical data:

Number of legs: 3 feet

External diameter: 20cm

Power: 1800w Voltage: 220V

❖ Maximum electric current on the wire:

- Power consumption device includes 2 mayso coils, power 1800W and some low power control devices We have amperage on wire

𝑈= 2 ×1800

220 = 16,36(𝐴)

- And with the condition of long-term heat test

Icpbt ≥ Icb = Imax

- Inside:

Icpbt: normal allowable current

Icb: forced current

Imax: maximum working current

Inferred we choose:

- 220V wire voltage

- Circuit breaker type 20A

- Type of wire with core cross section is calculated as follows:

S = I / J

Inside:

S: is the conductor cross-section, in mm2

I: current flowing through the square section, in Ampere (A)

J: permissible current density (A / mm2)

- Permissible current density of copper wire J ~ 6A / mm2

- Allowable current density of aluminum wire J ~ 4.5 A / mm2

Actual for the model:

- Total electric current is: I = 20A

- Conductor cross section is S = 20/6 = 3.33 (mm2)

Table 9: Conductor value [12]

So we need to choose conductors with a cross section of 4 (mm2) for total source wire, conductor cross-sectional area 2.5 (mm2) for wire of each oven, and smaller wire for others components

❖ Controller: PLC provided by the enterprise is

Figure 12: LOGO! 12-24 RCE siemens 6ed1052-1md00-0ba8[13]

LOGO! 12/24RCE, logic module, display PS/I/O: 12/24VDC/relay, 8 DI (4AI)/4DO, memory 400 blocks, modular expandable, Ethernet integr (LOGO! 12-24rce siemens 6ed1052-1md00-0ba8)

❖ Temperature sensor:

To satisfy the enterprise requirements of the accuracy of the baking process, we choose the PT100 type temperature sensor with its exact characteristics and its measuring coal also meets the working requirement of 50-300 degrees Celsius

Figure 13: PT100 M6 screw thermocouple temperature sensor [14]

The probe specifications:

❖ Temperature transmitter i1H12

We need to convert the signal from the PT100 temperature sensor into a 0-10V signal before transmitting into the analog input pin of the PLC

Figure 14: Temperature transmitter coil [15]

Through the transmitter, resistance signal of the thermal resistance can convert into 0-10V signal

- Accuracy: plus or minus 0.2 percent FS

- Diameter: Approx 45mm (1.77inch)

- Material: Plastic

❖ HMI Weintek MT8071IP

Figure 15: HMI screen

We utilize an HMI panel to make it easier to operate and monitor the system

We picked it since it and the PLC can interact with one another through Ethernet The price of the machine is also the request So that after considering the criteria of the heating machine HMI weintek is the best choice with the small amount of money but can qualify the SCADA system

-Processor : 32 bits RISC Cortex-A8 600Mhz

-USB Host: USB 2.0 x 1

-USB Client: Mirco USB

-RTC: Built in

-Ethernet port: 10/100 Base – T x 1

-COM port: COM 1 RS-232, COM2 RS-485 2W/4W

- Enclosure: plastic

❖ Expansion Module for LOGO!

To operate the pump directly from the PLC, as well as monitor and control the

system using Factory IO software, we need to add an extension module

Figure 16: Expansion module for LOGO!

-Voltage supply input: 12/24V DC

-Outputs : Relay

-4 DI (Digital input)

-4 DO (Digital output)

❖ AM2 AQ Analog output module

Figure 17: Analog output modules

LOGO! AM2 AQ expansion module for LOGO! 8

-Voltage supply: 12/24V DC

-2 AO (Analogue Outputs)

-0-10V or 0/4 – 20mA

❖ Calculation about the cylinder for taking baked product out the mold

Figure 18: Cylinder

The input parameters:

-Due to the heating furnace of the machine is about 210 mm long, compared with Vietnam's cylinder standard (TCVN), we choose the Piston S = 200 mm journey

- The weight of the input mold ranges from 500g-1000g, for a general calculation, we choose the largest weight for this calculation m = 1000g

Materials used: galvanized Iron box

Advantages: Galvanized Box Steel is a type of 1-layer galvanized steel at high temperature that helps protect the inner Steel from contact with outside air Better abrasion resistance than Black Box Steel, avoid rust, up to 50-60 years of service life

Table 10: Thermal conductivity

Conclusion: Galvanized steel box has a low coefficient of thermal conductivity, so it will have good heat storage capacity, suitable for use for heating Besides, its price is also quite cheap, easily removable for users, durable

Figure 19: Galvanized steel box[16]

❖ Cover:

Materials used: corrugated iron

Reason to choose materials: Easy to process, cheap price, easy to find, less deformation due to heat