AUTOMATION AND SIMULATION OF A STORING SYSTEM AT
SEMPER COMPANY
Bachelor Degree Project in Industrial Engineering Bachelor Level 30 ECTS
Spring term 2020 Ion Echeveste Zayas Sergio Piqueras Raso
University supervisor: Klas Hedenberg Company supervisor: Simon Wahlgren Examiner: Magnus Holm
i SUMMARY
The purpose of this bachelor's degree project is to address the problem of automation of a storing system complex enough to be able to understand and manage the most important and critical aspects of the storage plant. The plant has been designed and built in a simulation program called Simumatik due to its obvious simplicity in comparison to what it would take to assemble it in the real plant.
Therefore, some technical aspects have been integrated in connection with OPC-UA and with programming of CODESYS. Thus, a system with a variety of components has been proposed in aim to get as close as possible to a storing plant and a real distribution. The system includes ten conveyors. The bags are moved from the filling station to a door where the next operator take each bag.
In turn, the resolution of the problem has been tackled from a realistic and general point of view so that all the final objectives of automation systems are achieved, such as the design and organization of a plant, control, and supervision.
In general terms, the outcome of the final degree project is a deep analysis of current production, and a new storing processes with an automation solution and leveled production line as well. This automation would increase the flexibility of the operator as well as decrease the number of tasks of the operator and therefore it would be more efficient. The project begins by facing a problem in which the limitations are defined beforehand, which meets a complex and new requirement according to the development of a final degree project. This is equivalent to designing a storing plant with all the transport and distribution equipment in combination with sensors that provide information on the system.
ii ACKNOWLEDGMENTS
We would like to dedicate this section to everyone that has helped us in this Thesis that has given us major knowledge and experience in the field of automation and simulation, but this time in a real case at Semper Company.
First of all, we would like to thank Semper for giving us this great opportunity to becoming one more of their team for three months. Also, we would like to thank our supervisor at the Company, Simon Wahlgren, for supporting us throughout this project with important input, being so attentive, and the commitment. We feel very lucky for the supervisor at the University of Skövde assigned to us, Klas Hedenberg, that has given us so much advice and guidance throughout all the thesis, being available whenever we needed it.
Last but not least thanks to our families for their support given through our engineering degree and make this possible.
iii CERTIFY OF AUTHENTICITY
This thesis has been submitted by Sergio Piqueras Raso and Ion Echeveste Zayas to the University of Skövde as a requirement for the degree of Bachelor of Science in Production Engineering.
The undersigned certifies that all the material in this thesis that is not my own has been properly acknowledged using accepted referencing practices and, further, that the thesis includes no material for which I have previously received academic credit.
Sergio Piqueras Raso Ion Echeveste Zayas
Skövde 2020-05-18
School of Engineering Science
iv KEYWORDS
OPC: According to OPC Foundation “OPC is the interoperability standard for the secure and reliable exchange of data in the industrial automation space and other industries. It is platform-independent and ensures the seamless flow of information among devices from multiple vendors. The OPC Foundation is responsible for the development and maintenance of this standard” (OPC Foundation, 2008).
OPC-UA: The OPC Unified Architecture (UA), released in 2008, is a platform- independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework.
Building on the success of OPC Classic, OPC UA was designed to enhance and surpass the capabilities of the OPC Classic specifications. OPC UA is functionally equivalent to OPC Classic, yet capable of much more.
(OPC Foundation, 2008).
PLC: A programmable logic controller (PLC) is an industrial device that is used to control a system. It was created for high-reliability purposes.
OSI: Open System Interconnection (OSI) model a reference model for network protocols created in 1980 by the International Organization for Standardization (ISO). It has been published since 1983 by the International Telecommunication Union (ITU) and, since 1984, the International Organization for Standardization (ISO) has also published it as a standard. Its development began in 1977.
“The model uses layers to help give a visual description of what is going on with a particular networking system. This can help network managers narrow down problems (Is it a physical issue or something with the application?), as well as computer programmers (when developing an application, which other layers does it need to work with?)”. (Shaw, 2018).
v TABLE OF CONTENTS
SUMMARY ... i
ACKNOWLEDGMENTS ... ii
CERTIFY OF AUTHENTICITY ... iii
KEYWORDS ... iv
TABLE OF CONTENTS ... v
LIST OF FIGURES ... viii
LIST OF TABLES ... x
1 INTRODUCTION ... 1
1.1 Background ... 1
1.2 Problem Statement ... 1
1.3 Aim of Project ... 2
1.4 Research Questions ... 2
1.5 Sustainability development ... 2
1.6 Project Directives ... 5
1.7 Product Description ... 5
2 METHODOLOGY ... 6
2.1 Approach ... 6
2.2 Design and Creation ... 6
2.3 Data and Information Collection ... 7
2.3.1 Literature Study ... 7
2.3.2 Interviews ... 8
2.3.3 Measurement ... 9
3 FRAME OF REFERENCE ... 10
3.1 Simumatik ... 10
3.2 Codesys ... 10
3.3 Communication ... 11
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3.3.1 OPC ... 11
3.3.2 Ethernet/IP ... 11
3.4 PLC ... 12
4 THEORY ... 13
4.1 Strategies and methodologies ... 13
4.1.1 PDCA ... 13
4.1.2 Guidelines for Layout Development ... 14
4.1.3 SWOT analysis ... 15
4.1.4 Decision Matrix Table ... 17
4.2 Lean philosophy ... 19
4.2.1 Go and see yourself ... 19
4.2.2 Standardization ... 19
4.2.3 Lean ergonomics... 20
5 CURRENT PRODUCTION ... 21
5.1 Current Layout ... 21
5.2 Production flow ... 22
5.3 Operator tasks ... 24
5.4 Idea Generation ... 27
5.4.1 Brainstorming ... 28
5.4.2 First Suggestion ... 29
5.4.3 Second Suggestion ... 30
5.4.4 Third suggestion ... 31
5.4.5 Fourth suggestion ... 32
5.5 Production equipment ... 33
5.6 Ergonomics ... 33
6 IDEA ANALYZE & SELECTION ... 34
6.1 SWOT Analysis ... 34
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6.1.1 Sergio’s Decision Matrix ... 35
6.1.2 Ion’s Decision Matrix ... 36
6.1.3 Simon’s Decision Matrix ... 36
6.1.4 Selection of idea ... 37
7 DEVELOPMENT OF THE SELECTED IDEA ... 39
7.1 Creation of component ... 39
7.2 Creation of the system ... 41
7.3 Coding the system ... 42
7.4 Flow chart ... 44
8 RESULTS ... 46
8.1 New Operator Tasks ... 46
8.2 Efficiency ... 48
8.3 Estimated Investment Cost ... 50
8.4 Visualization of the system ... 51
8.5 Requirements fulfillment ... 52
9 CONCLUSIONS & RECOMMENDATIONS ... 53
10 REFERENCES ... 55
Appendix A - Blender 3D-models ... 57
Appendix B - Creation of Components in Simumatik ... 60
Appendix C - The structure tree ... 64
Appendix D - Coding the system ... 68
Appendix E - Components costs for the investment ... 88
viii LIST OF FIGURES
Figure 1. 1:Product used ... 5
Figure 4. 1:PDCA Diagram ... 13
Figure 5. 1:Plant Dimension ... 21
Figure 5. 2:Bag placed in Filling station ... 22
Figure 5. 3:Weight measurements in HMI Panel ... 22
Figure 5. 4:Sealing Station ... 23
Figure 5. 5:Worksite layout before automation (zero layout) ... 25
Figure 5. 6:Spaghetti Chart before automation ... 26
Figure 5. 7: First Suggestion Layout ... 29
Figure 5. 8:Second Suggestion Layout ... 30
Figure 5. 9:Third Suggestion Layout ... 31
Figure 5. 10: Fourth Suggestion Layout ... 32
Figure 6. 1: Evaluation of Ideas... 38
Figure 6. 2: Criteria Improvement ... 38
Figure 7. 1: Blender component ... 39
Figure 7. 2: Creating a component in Simumatik ... 40
Figure 7. 3: Component created in Simumatik ... 40
Figure 7. 4: Empty System in Simumatik ... 41
Figure 7. 5: System created in Simumatik ... 41
Figure 7. 6: Sub-operations shown in Simumatik ... 42
Figure 7. 7: Flow chart 1 ... 44
Figure 7. 8: Flow chart 2 ... 45
Figure 8. 1: Worksite layout after automation ... 46
Figure 8. 2: Spaghetti Chart after automation ... 48
Figure 8. 3: System 1 ... 51
ix
Figure 8. 4: System 2 ... 51 Figure 8. 5: System 3 ... 52
x LIST OF TABLES
Table 4. 1: Internal and external factors example ... 15 Table 4. 2: Decision Matrix example ... 18 Table 6. 1: Internal and external factors to analyze the ideas suggested ... 34 Table 6. 2: Sergio's Pugh Matrix. According to the baseline and the choices Sergio has made, the idea 2 obtains the highest grade ... 35 Table 6. 3: Ion's Pugh Matrix. According to the baseline and the choices Ion has made, the idea 2 obtains the highest grade ... 36 Table 6. 4: Simon's Pugh Matrix. According to the baseline and the choices Simon has made, the idea 2 obtains the highest grade ... 36 Table 7. 1: Type of FB that belongs to what Sub-operation... 43
1 1 INTRODUCTION
This section introduces the background, the aim, and the delimitations of the project.
1.1 BACKGROUND
Semper has been around since 1939. It all started when Ninni Kronberg caught up with a way to dry milk into powder. Today, Semper's primary focus is baby food, gluten-free and breast milk replacement. Products are developed together with doctors, nutritionists, researchers, and connoisseurs.
Semper thinks everyone has the right to good food. Naturally good food without strange additives. Children and adults with special dietary and nutritional needs should feel secure about what they eat.
The automation of production lines has lately increased in industrial manufacturing due to the technological breakthrough. In fact, companies search for better and faster manufacturing processes to be competitive in the area they are working on.
Continuously researches and designs in production lines need to be made to improve the processing times of the product manufactured.
Thus, the need for automation and production development is essential to create an effective production processes, which will lead to an increase in production. It allows a good management of the companies and speeds up the processes, providing greater productivity.
This thought of continuous improvements involves the philosophy of lean manufacturing which means to create more value by reducing the non-value-added work. The strategy (originated from Toyota) is based on achieving the shortest possible cycle time and the highest throughput by increasing the value-added time and eliminating the waste.
Currently, the company is implementing this philosophy of manufacturing progressively as many of the processes are needed to be perform with the aid of an employee.
1.2 PROBLEM STATEMENT
SEMPER Company has invested a lot of effort in improving and automating with cutting- edges machines a milk powder production line. These machines are capable of filling a big bag in a short time, but when it comes to seal and store those big bags, it is not automated and therefore many tasks have to be done manually by the operator. This manual labor makes the operator job very uncomfortable and stressful, as well as it can cause physical and mental problems. Besides, it slows the production capacity and the production cannot be running with the operator’s absence.
2 1.3 AIM OF PROJECT
The purpose of the final degree project is to come up with an idea of automation the storing system, build that model in a simulation program and eventually, running and showing it to the company.
• The main objective is to create a simulation of the storing system once a deep study of how much space is available to implement equipment that fits has been done. This objective consists in coming up with several ideas and then compare them, seeing which one meets the company’s requirements the most, considering from the operator’s ergonomic to the investment needed.
• Secondly, the system should be able to store all the bags automatically. That means that the system should be able to work by itself with the minimum interventions of the operator.
• Lastly, another point to consider is to be as efficient as possible. Therefore, the production would only stop when an error occurs and also make this improvement economically profitable.
1.4 RESEARCH QUESTIONS
The very first step is to create a general concept of the ideas of what will be studied to see which development processes need to be followed. Thus, the main questions that should be considered are:
-How the automation processes will be designed in order to make the production more efficient?
-What is the space available at the plant? An extension of the area could be done?
-Which equipment that fits in the area will be used to build the automated process?
1.5 SUSTAINABILITY DEVELOPMENT
Since the term 'sustainable development' was coined in 1987 in a report by the UN World Commission on Environment and Development, the so-called Brundtland report. In this report, sustainable development was defined as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”
(World Commission on Environment and Development, 1987). This definition reflected the gap that existed between the conservation of the ecosystems and economic development. These two activities were perceived as being incompatible (Franceschini &
Pansera, 2015). So, how can we link sustainability up to a topic as technological as automation? The broad definition of sustainable development was adopted by (Labuschagne, Brent, van Erck, 2005) to businesses as “the adoption of business strategies and activities that meet the needs of the enterprise and its stakeholders today while protecting, sustaining and enhancing the human and natural resources that will be needed in the future”.
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In this section it will be to see how automated manufacturing processes can affect the ecosystem and in which way can it be reduced in both, environmental and economic impacts.
Different aspects must be considered to assess the sustainability in manufacturing systems. Thus, when it comes to automating a manufacturing process, it is necessary to know which specifications and parameters need to be assessed to know when it could be called a sustainable system. To assess sustainability, three different fields are going to be discussed, by looking at the society, environment, and economy.
Economically, an initial investment of new equipment must be considered for the company’s economic growth-obviously by using current company’s resources available that will contribute to a reduced investment, such as conveyors for the transportation of the powder-filled bags, automated arms to place the bags properly in the tube where the powder is push through. As mentioned before, the manufacturing processes are a significant part to make the sustainable economic growth. The equipment will contain efficient machines in which its proper use will lead to a reduction will minimize the production cost. Some indicators that show the economical sustainability aspect in this context are the followings:
• Extraction costs
• Electricity costs
• Equipment costs
• Revenues
Social sustainability can be defined as “a process for creating sustainable successful places that promote wellbeing, by understanding what people need from the places they live and work. Social sustainability combines the design of the physical realm with the design of the social world – infrastructure to support social and cultural life, social amenities, systems for citizen engagement, and space for people and places to evolve.”
(ADEC, s.f.). It seeks different ways of combining the human and social aspects into the automated processes. This implies considering the possible negative effects that can have an impact on the operator's safety, health, and well-being. In our case, having only an operator working per shift, different clear rules of well-being in the workplace ought to be imposed. Focusing on the operator labor, by applying optimization of efforts will likely minimize the harmful effects that can appear within the 8 hours shift they carry out every day. Some indicators can be used to 'measure' the social sustainability aspect:
• Employee salary
• Percentage of employees with limited contracts
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• Number of accidents (e.g. falling bags)
• Social benefits per employee
• Percentage of workers with yearly check-up
Regarding environmental sustainability, encompasses everything related to the earth's ecosystem. In this context, the future automated processes we are facing must not compromise the ecosystem's carrying capacity. Thereby, the new equipment will be demanded CE marked to ensure that the machines fulfill the basic requirements as to safety, health, function, and environment. Electricity consumption is another issue that must be considered since it will have a greater or lesser impact depending on how much carbon footprint is released. Thus, several consumption measurements which will cover both production and longer production stops in different shifts and days should be made.
Another good point to consider is the equipment life cycle time. For instance, the function that the conveyors provide is 'moving the bag from one stage to the next for a given number of cycles', where the number of cycles is defined by the number of shift running within a whole year and thereby the number of years of use can be calculated. As a consequence, the most meaningful way to contribute to more sustainable automation would be to reduce electricity consumption, which will result in a decrease in carbon footprint. Besides, the following indicators will help to look deeper into the ecological sustainability:
• Embodied energy
• Global warming
• Abiotic depletion
• Ozone layer depletion
• Terrestrial ecotoxicity
In conclusion, in this section, it is explained how the sustainability in automation has to be assessed. Regarding the 17 goals of sustainable developments (SDGs), the ones that are referred in this section are the followings (United Nations, Department of Economic and Social Affairs, 2016):
• Good health and Well-being
• Affordable and clean energy
• Industry, innovation and infrastructure
• Climate Action
Also, different actions that can be applied in order to arrive at a more sustainable processes are discussed and being aware of how it can help to avoid sub-optimization at
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the workplace. Fundamentally, even though the implementation of automated equipment may be a minor contribution to the carbon footprint, what has to be considered and will be the most sustainable way would be to reduce the electricity consumption of the equipment in its use.
1.6 PROJECT DIRECTIVES
SEMPER Company is looking for a storing system that provides them a continuous flow of the powder milk production line as well as a more automated storing system so the operators can have better working conditions. According to Aim of project (section 1.3), the most important factors to take into account are the following ones:
• Production Capacity
• Available floor space
• Material handling
• Flexibility
• Ergonomic
• Cost of implanting
1.7 PRODUCT DESCRIPTION
A bag that contains powder milk coming from a highly automated machinery process is the product that needs to be managed. Semper’s bags can support a weight of approximately 1000 kg, although they are only filled up to 570 kg. The bag dimensions are 95x95x195 cm. Certainly it is necessary to use an industrial bag of such dimensions because they have to withstand possible impacts and as mentioned before, bear a high weight. Figure 1.1 shows the product used.
Figure 1. 1: Product used
6 2 METHODOLOGY
In this section will be explained different aspects in order to go deeper into the automation and specify how the project is going to be faced.
2.1 APPROACH
Researching methods and tools related to the work that is going to be done can be found on the journals or books, and they are very important to achieve scientific results. In this project the method that is going to follow is Lean philosophy.
This method will have different models that are explained in the “Strategies and methodologies” area. The models are PDCA (Plan, Do, Check, and Act) and Guidelines for Layout Development.
The thesis project will include a theoretical study part where it is explained everything related to the automation. This part will describe the initial problem that the project is facing. Moreover, it will be described the way it is come up with the best idea to solve the problem and how it has been implemented. Finally, the results will be published as well as the knowledge we gained.
2.2 DESIGN AND CREATION
The design and creation research focuses on developing new IT products, also called artifacts. Types of IT artifacts include (March & Smith, 1995): constructs, models, methods, and instantiations. For this project, the research involves analyzing, designing, and developing a realistic computer animation (simulation). Typically design and creation are a problem-solving. It uses an iterative process involving five steps (Vaishnavi &
Kuechler, 2004): awareness, suggestion, development, evaluation, and conclusion.
Thinking about several suggested tentative solutions leads to greater awareness of the nature of the problem; the development of a design idea leads to an increased understanding of the problem (Briony J Oates, 2006). In this way the researcher learns through making, so new alternatives may appear while working.
In this project the design and creation are focused on the automation of the storing part of the production line which could be seen as a bottleneck. Thus, deep research was performed to gather as much valuable information as possible. The gathering information was performed to get the insight needed to be able to generate reliable and suitable ideas by using different methods, such as observations, interviews, documentation collection.
For this reason, it was able to set suitable concepts by doing a description in detail that is reflected throughout the project (Zaidah Zainal, 2007).
7 2.3 DATA AND INFORMATION COLLECTION
The collection of information and data performance that has been done will be explained and described in the following sections.
2.3.1 Literature Study
This subsection includes previous literature studies to examine different methods applied, researches questions in our theoretical framework, backgrounds, common concepts, and practice identified. This is a way to have an overview of related things that can be helpful for this project, which will be used to compare different data points and a regression analysis of benefits with reliability related to the automation of the processes. Since this project is something that has to be totally re-designed and new, the literature studies that have been used for this project, which is certainly short, was searched and collected from scientific articles and journals overall. The approach will help to see how to face the majority issues of material handling, lead time, and labor cost problems in the project.
Our scope is focused on the subject of this project, aiming to solve some limitations through automation, such as specific setup, cycle time, and ergonomic problems.
The literature studies carried out follow the reviews hereunder:
• This project is going to take advantage of Virtual Commissioning since a simulation with all the virtual models is going to be built to replicate real-life equipment, and also to prove it is a reliable project to carry out for the company.
VC has many benefits, but one of them is that it reduces the time spent in programming. There is an experiment described by Reinhart & Wünsch (2007) to draw conclusions regarding whether the use of VC reduces the time spent on it compared to the projects that used only PLC programming. This experiment is about thirty people that built a PLC program for a machine using standard tools, and another group of thirty people that used a simulation model to perform a VC before implementing it in real life. The results of this experiment showed that the time was reduced by 75% when the CV was used, compared to the group that did not use VC. It can be concluded that this experiment clearly shows a benefit in time and quality when using VC. Besides, there must be said that this experiment was conducted with a quite simple setup and thus, maybe not used to perform larger projects (Reinhart & Wünsch, 2007).
• The content in this article is an overview of what will be discussed in the project.
It is very educational at the introductory concept related to the latest trends in Industrial Automation. Also, it reflects why humans “should remain in control while automation plays a subservient role, therefore functions are automated only if they improve system performance without reducing human involvement, situation awareness, or human performance in carrying out the intended task safely, efficiently and effectively” (Akogbe, 2015).
• This journal talks about how to address automation layout problems (in this case, in the footwear industry), considering how to deal with new arrangements of
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machines in the site to minimize the sum of material handling and re-layout costs.
It is known that the main aim is to minimize the manufacturing costs and increase productivity. By assessing alternative scenarios, it can be decided whether the layouts are applicable in real life. Here it is reflected how hard to deal with these real-life problems and usually, they are large problems in size. Moreover, the content of this journal shows how the re-layout costs and the sum of material handling can be improved by proving it mathematically (Ulutas & Islier, 2015).
2.3.2 Interviews
This section describes several interviewing questions from a solution-focused approach.
The reason why the interview is done is to have different approaches of the problem and reach faster to the main problem. Besides, it will allow to understand how the problem can solve better as well as easier. By interviewing, it will be discovered which are the strengths and weaknesses will help to go in-depth through the main problems that must be addressed. This is a popular way of gathering quality information directly from the people who are familiar with the area of operation. It was used a semi-structured interview which means that some questions are predetermined, but also new questions can arise when conducting the interview (Griffee, 2005).
Firstly, it was decided who was going to be interviewed, starting with the supervisor of the company, and finishing with the operators who are currently in the situation. It began by explaining the project's purpose and which parts are interesting, for the interviewee to have an active interpretation of the specifications given.
In addition, a selection of a place had to be done due to the high noise level the machinery made inside the working area. Thus, it was decided to take them out to the locker room right across the area. Once there, the interview began by asking written questions beforehand, which sometimes was spent in studying what wanted to ask. Following questions were used to get the feedback from the respondent:
• Where do you think the real problem of not being automated is?
• What is the most tedious labor for you?
• Which things do you think can improve ergonomics in your job?
• What would you change?
• Do you feel like you have no time to do other tasks in case of an emergency?
How to collect data from the responses has to be considered, for example, listen-only, or maybe listen and take notes on the spot. In this case both processes were carried out. The resulting feedback may be positive or negative. The idea is to see which themes have the respondent focused the most so the evaluator can finally evaluate and comes to understand
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what the respondent is talking about. Also, read the responses several times over a while to get familiar with what has been said.
Finally, the conclusions drawn from the respondents were mainly the transportation of the bags from the filling station to the sealing and vacuum-packaged station as the operator has to take the forklift and move it manually very carefully since the bag might fall off. The respondents tended to say the same thing, even though in a slightly different form.
2.3.3 Measurement
Gathering information directly from the production plant is needed to identify which changes can be made in the layout as well as the equipment that fits better in the area.
Thus, the measurements that have been made are the following:
• Cycle time: defined as the average time between the start of production of one unit and the start of production of the next unit, when these production starts are set to match the rate of customer demand. In our case, it will be needed to know how often a bag is filled, and when it would arrive at the warehouse.
• Weight and size bag: necessary to use the proper equipment.
• Plant dimension: depending on the space available and the current situation, the most optimal alternative of layout is chosen, and it will be developed in detail.
• Operator handling time: this is the measurement of how long an operator spends resolving each process while working. By adding the automation processes, this time will be improved and lean goals in the elimination of non-value-added waste will be achieved.
• Throughput: this can be considered to know whether the time required for the product to pass through the entire manufacturing process is improved with the new automated equipment implemented in the last process of the chain production.
As conclusions for the prior sections, the literature approach will help to see how to face the majority issues of material handling, lead time, and labor cost problems in the project. Thanks for interviewing the employees, getting to the root of the problem was clearer. By obtaining the measurements mentioned, a more realistic building of the model and simulation can be made.
10 3 FRAME OF REFERENCE
In this section the followings software has been used to build the simulation system.
The reason why these software’s are used are that Simumatik is an emerging software that allows to create components from scratch and the behavior can be defined by code.
In contrast, Codesys has been used because is an open software capable of coding PLC in many languages. How Simumatik and Codesys are used are explained more deeply in the Appendix A and Appendix B.
3.1 SIMUMATIK
Simumatik is a 3D simulation program for automation technologies. It allows the project to build a virtual factory, plant, and so on, by using a common industrial part. Simumatik also includes many scenes inspired by typical industrial applications such as turning conveyors, transfer conveyors, conveyors with doors, and also with Scara Robot.
The most common scenario is to use Simumatik with PLC since PLCs are the most common controllers found in industrial applications. Moreover, Simumatik is capable to communicate with other programs via OPC-UA. That is why it can communicate with robots.
Simumatik has also the possibility to add not just electrical components, but also pneumatics so a big and very realistic virtual factory can be created.
In order to connect Simumatik to PLC and be able to run the program properly Simumatik has the option to use the OPC tool. This tool will be explained in the next step. Thus, Simumatik can be connected to many different programs at the same time via OPC-UA.
Besides, PLC and Simumatik can be connected also via Ethernet.
3.2 CODESYS
Codesys (Controller Development System) is “a development environment for programming controller applications according to the international industrial standard IEC 61131-3” (Codesys, 2019). The license of CODESYS is free of charge and can be installed legally for free. The software tool covers different aspects of industrial automation technology with one surface.
Codesys has different programming methods:
• IL: Instruction List.
• ST: Structured Text. One is very similar to the C language.
• FBD: Function Block Diagram. It is a graphical language where each block has a specific task. It normally has one or more input and an output.
• CFC: Continuous Function Chart.
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• SFC: Sequential Function Chart. It is a recent way of programming. It is based on GRAFCET.
• LD (Ladder diagram): It is the most usual language and the one that is going to be used for programming.
3.3 COMMUNICATION
3.3.1 OPC
Codesys has an internal OPC server that is in charge of communicate with all the periphery. Codesys describes the product as:
OPC (Open Platform Communications) is a standard interface that provides access to the data of an automation process. The main task of the CODESYS OPC Server is the exchange of data (read/write) with the controller for example for visualizations or process data logging programs. The CODESYS OPC Server is an additional Windows program.
It is included in the setup of the IEC 61131-3 Development System CODESYS but requires a USB dongle license for usage.
MatrikonOPC, one of the companies that is dedicated to the communication thought the OPC servers define as:
“An OPC server is a software application that meets one or more specifications defined by the OPC Foundation. The OPC server interfaces on the one hand with one or more
data sources using its native
protocols (typically PLC
DCS, scales, I/O modules...) and on the other hand with OPC clients (typically SCADA, HMI, report generators...). In an OPC/Server OPC client architecture, the OPC server is the slave while the OPC client is the master. Communications between the OPC client and the OPC server are bi-directional, meaning that clients can read and write to devices via the OPC server.”
To connect among PLC and other devices that can be used in this project OPC communication is the best tool.
3.3.2 Ethernet/IP
Ethernet/IP is a communicating industrial protocol that it is inside of the OSI model.
Ethernet/IP can be described as:
“Ethernet/IP (IP = Industrial Protocol) is an industrial network protocol that adapts the Common Industrial Protocol to standard Ethernet. Ethernet/IP is one of the leading industrial protocols in the United States and is widely used in a range of industries including factory, hybrid, and process. The Ethernet/IP and CIP technologies are managed by ODVA, Inc., a global trade and standards development organization founded in 1995 with over 300 corporate members.
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Ethernet/IP uses both of the most widely deployed collections of Ethernet standards –the Internet Protocol suite and IEEE 802.3 – to define the features and functions for its transport, network, data link, and physical layers. Ethernet/IP performs at a level session and above (level 5, 6, and 7) of the OSI model. CIP uses its object-oriented design to provide Ethernet/IP with the services and device profiles needed for real-time control applications and to promote consistent implementation of automation functions across a diverse ecosystem of products. Also, Ethernet/IP adapts key elements of Ethernet’s standard capabilities and services to the CIP object model framework, such as the User Datagram Protocol (UDP), which Ethernet/IP uses to transport I/O messages” (Codesys, 2020)
The use of Ethernet/IP is continuously increasing due to its “high performance, integration between factory installations and IT/IoT-system as well as the industrial Internet of Things in general” (HMS Industrial Networks, 2019).
3.4 PLC
A programmable logic controller (PLC) is a computer used in automatic engineering or industrial automation, to automate electromechanical, electro-pneumatic, electro- hydraulic processes and so on. PLC is implemented in the industry to improve or automate production processes as well as production lines or mechanical attractions.
PLCs can manage and control multiple input and output signals, extended temperature ranges, electrical noise immunity, and resistance to vibration and shock. The programs of the PLCs are typically stored in a battery, backup, or non-volatile memory. A PLC is an example of a real-time system, where output results must be produced in response to input conditions within a limited time, otherwise, it will not produce the desired result.
13 4 THEORY
In this part the theoretical background is presented. It will explain briefly some of the the lean philosophies as well as the different tools that can be used to follow the leans philosophy. This part will explain which tool will be used and the results obtained from it.
4.1 STRATEGIES AND METHODOLOGIES
Nowadays Lean philosophy is widely spread in the society. It has been implemented more and more, starting from a well-known brand company like Coca Cola to a very small company.
There are several tools that may help to follow Lean philosophy such as 5S, Andon, Heijunka (Levelling), Just in Time, Kaizen, Kanban, Muda, Mura, and Muri. Therefore, the tools that are going to be used are described since the project consists of a significant improvement.
In addition, and to choose the best idea and develop it, a strategy has to be followed. For this, in order to know the strengths and weaknesses of every idea a SWOT analysis and Pugh matrix table is used.
4.1.1 PDCA
PDCA (Figure 4.1) is an iterative methodology for implementing improvements. It is used for solving problems. As it is a continuous improvement philosophy it is usual to look it as a wheel, so it never ends (Vorne, 2011).
• Plan: Issues list, customer requirement, define the problem, collect facts, and root fact.
• Do: Implement the solution in the practice.
• Check: Evaluate the results.
• Act: Correct the errors and standardize them.
Figure 4. 1: PDCA Diagram
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This was used when building the new model for the storing system was being created.
While the model was being implemented, it was analyzed and new improvements were made. This method should be put into practice, in a future as well, once the implementations of the improvements have been made to keep its philosophy of continuous improvement.
4.1.2 Guidelines for Layout Development
There is no standardized method when it comes to developing a new layout. The proper method is to go step by step. There have been established ten steps to create a good layout.
The steps are the followings:
1. Set up Goal - The objectives have to be established. Thus, prior deep research must be done.
2. Current State - The current state of the layout has to be verified, how it looks like and how it works (as can be seen in section 5).
3. Resources need - The needed resources have to be implemented in the layout requirements. Meaning which equipment is going to be used for the automation.
4. Space Need - The needed space has to be set.
5. Mapping Relations - Relations machinery and place are planned to aim to know how they should be placed relative to each other.
6. Grade Relations - The most important relations are set to know which process is most important and which one must be fully automated (SWOT analysis, section 4.1.3).
7. Outline Layout - Taking into account the last step, the functions are placed in the drawings.
8. Analyze - Pros and cons are analyzed of the different outline Layouts (section 5.4.2-5.4.5)
9. Alternative - Different alternative of the layout is developed. Then, the best one is chosen (Pugh Matrix, section 6).
10. Detail Plan - The best layout is developed in detail (Simumatik, section 7.2).
15 4.1.3 SWOT analysis
The SWOT analysis (Strengths, Weaknesses, Opportunities, and Threats) is a tool that studies the situation of a company, institution, project, or person, analyzing its internal characteristics (Weaknesses and Strengths) and its external situation (Threats and Opportunities) in a square matrix. The table, such as Table 4.1 is a tool to know the real situation in which an organization, company, or project is, and to plan a future strategy.
This method is considered to have been originally suggested by Albert S. Humphrey during the 1960s and 1970s in the United States during research at the Stanford Research Institute aimed at discovering why corporate planning was failing. This resource produced a revolution in the field of corporate strategy (Schooley, 2019). The objective of the SWOT analysis is to determine the competitive advantages of the company under analysis and the generic strategy that best suits it according to its characteristics and those of the market in which it operates.
Table 4. 1: Internal and external factors example
INTERNAL FACTORS INTERNAL FACTORS
STRENGTHS (+) IMPORTANCE WEAKNESSES (–) IMPORTANCE
1 Fully/Partially Automated Process 8 1 Quality checks 5
2 Time Saving 6 2 Space required 9
3 Secured access 7 3 Long production cycle 3
4 Increase productivity by eliminating wastes 7 4 Amount of tasks done by the operator 7
5 Ease of implanting 8 5 Possibility of the bag to fall down 10
6 Ergonomics 9 6
EXTERNAL FACTORS EXTERNAL FACTORS
OPPORTUNITIES (+) IMPORTANCE THREATS (–) IMPORTANCE
1 Seeking new ways to enhance 7 1 Hygiene 10
2 Huge investment 9 2 Huge investment 9
When should a SWOT analysis be performed?
A SWOT analysis should be performed before any kind of company action whether new initiatives, revamping internal policies, considering opportunities to pivot, or altering a plan midway through its execution are exploring. It also can be used to check that the current business can be improved in some parts. Therefore, the table contains the main points that could be improved and how to do it.
A general approach of the business can be seen just by taking the time, to put together a formal SWOT analysis, and by doing this, a new way either to improve or eliminate the weaknesses and developing its strengths can be discovered.
It is effective to include other people in the process, ask for feedback and openly discuss any contributions made. The collective knowledge will allow you to adequately analyze your business from all sides (Schooley, 2019).
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Internal factors
The internal factors include Strengths (S) and weaknesses (W) which are the resources and experiences available.
These are considered the most common internal factors:
• Financial resources (funding, sources of income and investment opportunities)
• Physical resources (location, facilities, and equipment)
• Human resources (employees, volunteers, and target audiences)
• Access to natural resources, trademarks, patents and copyrights
• Current processes (employee programs, department hierarchies, and software systems)
External factors
External are directly connected or indirectly to an opportunity or threat and it is important to note and document each one. External factors cannot be controlled.
These are considered the most common external factors:
• Market trends (new products, technology advancements and shifts in audience needs)
• Economic trends (local, national and international financial trends)
• Funding (donations, legislature, and other sources)
• Demographics
• Relationships with suppliers and partners
• Political, environmental and economic regulations
After creating the framework and fill out the SWOT analysis, it is easy to come up with some ideas or strategies based on the results. Linda Pophal, owner and CEO of consulting firm Strategic Communications said: "these strategies should involve leveraging Strengths and Opportunities to beat weaknesses and threats. This is actually the area of strategy development where organizations have an opportunity to be most creative and where innovative ideas can emerge, but only if the analysis has been appropriately prepared in the first place" (Schooley, 2019).
17 4.1.4 Decision Matrix Table
A decision matrix, also called the Pugh matrix, evaluates and prioritizes a list of options.
It is used as a decision-making tool. Firstly, it is established a list of weighted criteria and then, every option is evaluated according to a criteria. This is a variation of the L-shaped matrix.
A decision matrix is a table that allows to identify, analyze, and rate the strength of connections between sets of information. Indeed, the matrix is especially useful for looking at large numbers of decision factors and assessing each factor’s relative importance.
When to use a Decision Matrix
A decision matrix is used during quality planning to select the goals and to develop process steps and weigh alternatives. For quality improvement activities, a decision matrix can be useful in selecting a project, evaluating alternative solutions to problems, and in designing remedies.
How to do a Decision Matrix
Identify alternatives. Do a brainstorming, for instance, to identify all the possible alternatives.
Identify decision/selection criteria. After ensuring that everyone has a clear and same understanding of what the criteria mean, they are written with a baseline score, meaning that a high score for each criterion represents a favorable result and a low score represents an unfavorable result. The criteria are listed down the left side of the matrix.
Assign weights. If some factors are more important than others, review and agree on appropriate weights.
Design scoring system. Before rating the alternatives, the team must agree on a scoring system so it should be determined the scoring range.
Rate the alternatives. For each alternative, assign a consensus rating for each decision criterion. The team may average the scores from individual team members or may develop scores through a consensus-building activity.
Total the scores. Multiply the score for each decision criterion by its weighting factor.
Then, total the scores for each alternative considered and analyze the results.
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Here below it is shown the Pugh matrix used for this case (Table 4.2). As can be seen, it contains the most important criteria selected along with their respective baseline agreed.
Plus, it is put the different ideas suggested to fill them up with the symbols “+, -, 0” in order to come up with an end addition result according to the values of each symbol (reflected in the table below).
Table 4. 2: Decision Matrix example
Problem/Situation:
1 2 3 4 5
Criteria Baseline Idea1 Idea2 Idea3 Idea4,Version1 Idea4 Version2 Totals Rank
Fully/Partially Automated Process 8 − + 0 + + 16 2
Ease of implanting 8 + 0 − − − -16 8
Ergonomics 9 − + 0 + + 18 1
Possibility of the bag to fall down 10 − 0 0 0 0 -10 7
Space Required 9 + 0 − − − -18 9
Amount of tasks done by the operator 7 − + + 0 0 7 3
Hygiene 10 − 0 + 0 0 0 6
Investment 9 + 0 − 0 0 0 5
0
Totals -18 24 -9 0 0
Rank 5 1 4 2 2
Alternatives Automation at Semper
19 4.2 LEAN PHILOSOPHY
As Ciarniene talks in his article (Čiarnienė and Vienažindienė, 2015), Lean manufacturing began as the Toyota Production System (TPS) in the Japanese automotive industry in the late '70s and early '80s. Lean production focuses on eliminating the waste, reducing the need to manage with large inventories and to create a high-quality production at the least cost. Lean manufacturing is a management philosophy that derives mainly from the 'TPS' to satisfy its specific needs in a restricted market when hard economic times arrive. This is a practice that considers all non-value-adding activities in the value chain to achieve an effective production. Lean can be described in different levels of abstraction: defined as a philosophy, a set of principles, and a set of practices. Lean has been studied and put into practice in many companies as one of the popular concepts, and it has been proved that it can be transferred and applied to a variety of industries and services.
4.2.1 Go and see yourself
Genchi Genbutsu means "real location, real thing" also known as "go see yourself", it is one of the most important tools of the Toyota Production System. It suggests that to know or understand the real issues that can arise one has to go where the main problem is and see it for oneself.
Therefore, Genchi Genbutsu is an important method that helps when it comes to sorting out any issue. Its philosophy is that if the problem is for example in a specific machine, it must be understood and resolved in the machine. As the production is created in manufacturing workshops, this is where engineers, technicians and so on have to spend their time solving the problem.
4.2.2 Standardization
Standardization is responsible for developing technical standards. These standards are used to increase safety, quality, reduce errors, waste, and so on.
Standardizing helps companies to achieve high-productivity and low-inventory that are important characteristics in the lean system. Productivity is increased when operators have standardized duties and work methods are well learned. Standardized work ensures a good quality because defects are reduced by standardization.
When a defect comes up and the main problem is detected to figure out whether the standardized work was followed or if modifications in the standardization are needed.
20 4.2.3 Lean ergonomics
Since working comfortable and with good ergonomics carry out good health for the worker and better results of the productivity, it is notoriously increasing the care of this aspect in the area of factories. The purpose is that the worker has to work easily and comfortably. This means that physical load lifting, many repetitions, and mental difficulties in work, and so on have to be avoided as much as possible.
In the next points are explained how to handle ergonomics within lean ergonomics.
1. Work to Cycle Time or Rhythm - Regular rhythm helps the body to work easier.
2. Standing rather than sitting - It creates flexibility for the body. Working between workstations, sitting down and standing up avoid to the body back, neck…
problems. To balance they suggest having standing and moving operators but with a frequent break with comfortable chairs.
3. Height adjustment - The workstation should have the opportunity to adjust the height to the height of the operator independently of the type of work or worker 4. Ergonomics 5S - The working posture should be in a natural position all the
working period. 5S should contain evaluations of work height, lifting, lightning, noise, etc.
5. Make use of visual warning devices - Lots of visual warnings can be used to aware the operator or worker that if the product is movable by humans or machines.
21 5 CURRENT PRODUCTION
The current production is divided into two different workstations (Filling station and Sealing station) where there could be one or more processes to do. These processes are the following ones.
In this part the processes and the operator tasks will be explained to have the approach of the production line and to understand better how it works.
5.1 CURRENT LAYOUT
The current layout of the production line is a square with the dimensions (in meters) shown in Figure 5.1. Mainly, there are two different workstations. The filling station and the sealing station.
As there are two filling stations, this operation never stops because a bag can be filled while the other one is being replaced. This workstation is placed on the left-hand side of the room. Besides, in front of those stations the sealing and vacuum station are placed, where the filled bags are moved using an electric forklift.
Moreover, two different little areas can be found at the bottom two corners of the image.
The changing room is placed on the right side and the left side is where the samples are left and picked up by another operator.
Regarding the type of layout from a theoretical perspective, it could be said it is a functional layout. This layout can be seen in how machines and operators are positioned.
It can be defined as (Lean Strategies International, 2015): “a functional layout is a workplace configuration in which operations/processes are organized by the type of work (function) they do”. In this case the machines are grouped according to the function they perform, the plant has the filling machinery in one area, as mentioned before, and the sealing and vacuum-packed in another area.
Figure 5. 1: Plant Dimension
22 5.2 PRODUCTION FLOW
1. Placing bag
First of all, when the filling station is empty, a bag is placed on the pallet and put into the filling pipe. The operator has to take into account that the bag has to be placed properly in the middle of the pallet (Figure 5.2).
Figure 5. 2: Bag placed in Filling station
2. Filling the bag
After placing correctly, the bag the operator has to update the new weight of the pallet plus the bag added. After doing it, the operator must press a button to send the
information to the machine, confirming that the product is ready to be filled. The bag is filled until a certain weight that is specified in the HMI (Figure 5.3).
Figure 5. 3: Weight measurements in HMI Panel
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3. Taking samples
Every batch needs to be controlled and the quality is a very important issue so the main product is food. That is why the hygiene and quality are the main factors to consider. To know and control every batch samples have to be taken to the laboratory and being analyzed.
4. Forklift transport to the sealing station
Later, the bag is moved to the next workstation. The bag is moved with the help of an electric forklift.
5. Stick stamps
In the wake of weighting and before sealing the bag 4 stamps are stuck, each in a side of the bag. In fact, every sample must have a stamp.
6. Sealing(x3)
As the bags have to be stored in a warehouse, the best way to store properly the powder milk is to seal and vacuum-pack every batch (Figure 5.4). The sealing is done by putting together both sides of the bag and heating them. This process is done 3 times to ensure that the bag is properly closed.
Figure 5. 4: Sealing Station
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7. Vacuum-packed
After the sealing is finished the air has to be taken out of the bag. This process is done with a pipe that is inserted in a hole of the bag. Then, the operator presses a button and the pipe start doing the vacuum.
8. Transport to the intermediate place
Finally, only when the bag is full of milk powder, correctly sealed and vacuum-packed, the bag is transported to an intermediate place where another operator will take it and wrap it with plastic to protect it from possible damages.
5.3 OPERATOR TASKS
How the production line works is explained above, but as one of the purposes of the project is to improve the ergonomics of the operator and simplify his/her task as much as possible, an explanation of the job of the operator will be necessary. Currently there are two filling stations, so the operator has to do this task two times. Therefore, the operator may be doing two different tasks at the same time. The visualization of the process of an employee’s movement at the selected worksite has been conducted with the help of a spaghetti chart, which is usually used in the initial phase of planning improvement actions. The diagram created allows for product observation and movement analysis in the different phases (Hys and Domagała, 2018).
The worksite of the operator, who does manual carrying of bags, placing them and taking samples is represented in the ‘zero layout’ of the analyzed current worksite in Figure 5.5, in which the operator performs independently 17 activities.
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Figure 5. 5: Worksite layout before automation (zero layout)
Description:
A. Filling worksite
B. Button to get the filling operation started C. Sealing and vacuum-packed devices D. Sampling worksite (stairs)
E. Delivering sampling F. Bags stockpile G. Exit worksite door
A list of all activities performed by the operator at the analyzed worksite before improvement is shown hereunder:
1. Moving the pallet to the filling station - “A”
2. Picking the bag and moving it to the filling worksite- “F”
3. Placing the bag in the filling station: the handles and the neck of the bag - “A”
4. Pushing the switch ON - “B”
5. Placing the bag properly while it is inflating - “A”
6. Pressing the start button in the HMI - “B”
7. Pressing the switch OFF whenever the bag is full -“B”
8. Taking samples -“D”
9. Putting the stamps to the samples and the bag 10. Carrying the samples to the next post -“E”
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11. Moving the bag onto the sealing and vacuum-packed worksite 12. Sealing the bag three times -“C”
13. Inserting the vacuum pipe - “C”
14. Pressing a button to vacuum -“C”
15. Visual assurance of the proper execution of performed activities 16. Removing the vacuum pipe -“C”
17. Moving the bag to the next post with the help of the forklift -“G”
It is obvious that the number of operations to follow is quite large in comparison to the time the operator has to spend in a cycle and that is the reason why automation is a good idea in this part. Indeed, the operator has to be very attentive all the time and does not have time to relax. This could lead to backache or stress since there are two filling stations and the job can be stressful.
The zero layout showing the employee’s movements at the worksite has been presented in Figure 5.5 with the help of the Spaghetti Chart diagram. This new Diagram (Figure 5.6) gives the number of trips, which have to be made by the employee during one cycle.
Figure 5. 6: Spaghetti Chart before automation
Based on the diagram analysis of the Spaghetti Chart it can be concluded that the number of trips made by the operator during a work cycle is ten. This clearly shows that there is a possibility of improvement in this area. Thus, automation will reduce considerably the
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number of trips the operator does every cycle. By doing calculations, this cycle has a duration of twenty min approximately. The improvements achieved by implementing automation will be explained later on.
5.4 IDEA GENERATION
When it comes to generating different ideas to find solutions to the organization's problems, there are different methods to be used and brainstorming is just one of these methods which have been used in this project.
28 5.4.1 Brainstorming
This popular method made to improve group problem solving is the process that has been followed to reach a final decision. The method is used to solve the problem of the following answer: How can be the system improved to make more simple and better work for the operator?
The method is reasoned by the following rules: no criticism, quantity over quality, and build on the ideas of others. This rule would increase the productivity of idea generation by reducing evaluation apprehension and by increasing synergy (Osborn, A.F, 1957).
Accordingly, the method identifies and examines the proposal of ideas from the members of the group. This is a process whereby the members generate ideas as they occur, regardless of the quality since it may stimulate the thinking of other member groups, leading to more ideas that could be very helpful. It is important to follow a critical rule, which is to be open to other’s ideas without judging in order to not neither conflicts nor verbal interactions among the members of the group. One risk that sometimes comes with cohesiveness is “groupthink” which decreases the range of ideas (VanGundy, 1984) A variety of ideas needed to be generated for the purpose of showing them to the company so as the brainstorming was performed by the two authors of the project, but also with the support of the company supervisor and employees at Semper. This had an estimated duration of a couple of days of brainstorming, one by our own discussing the different possibilities, which took four hours both in the morning and afternoon, verifying it with the supervisor the day after.
Once the brainstorming is done the Guidelines for layout development section has been followed to do the new layout suggestions more accurately (section 4.1.2).
29 5.4.2 First Suggestion
Firstly, it has been come up just simple and it is very similar to the current layout. The only different thing is just that some conveyor has been implemented so the operator does not have to take the forklift and therefore this makes easier the operator’s work.
The process starts in the filling station (1), where the bag is placed manually by the operator. Once the bag is filled, samples need to be taken by the operator, lower the handles of the bag and finally press a button to send the information to the machine, which means the bag is ready to be removed. Then the bag is moved to the sealing and vacuum- packed station (2) where, as the name suggests, the bag will be sealed and next vacuum- packed. This operation requires the operator’s labor since the tube that is used for the vacuum-packed needs to be inserted by him or her. This layout can be seen in Figure 5.7.
In addition, in the case there is already a bag at the sealing station, the bags that come next will be stacked on the previous conveyors.
Figure 5. 7: First Suggestion Layout
1
2
30 5.4.3 Second Suggestion
The second suggestion (shown in Figure 5.8) is a little bit more sophisticated than the previous one. Whereas the brainstorming was going on, it was concluded that the operator is too busy and barely has free time to do other tasks. In this layout a new filling station has been added and thus the time to fill all the bags has increased by 1.5, which makes the process more effective. This addition gives the operator more flexibility to do the different tasks assigned to his job.
Right after the filling station there is a conveyor that takes out the bag after the operator takes the samples and lower the handles. Later, in order to transfer the bag to the next station, a moving conveyor will be used.
As mentioned before in the prior suggestion, this station also requires the labor of the operator, for the sealing and vacuum-packed workstation (green).
Figure 5. 8: Second Suggestion Layout
