Design and product development
of a refrigerated mailbox for home
use
By
Noor Radhison
A THESIS SUBMITTED IN FULFILMENT OF THE
REQUIRMENENTS FOR THE DEGREE OF BACHLOR OF
ENGINEER IN PRODUCT AND PROCESS DEVELOPMENT
June 2021
Design and product development
of a refrigerated mailbox for home
use
Noor Radhison, nrn18001@student.mdh.se
Supervisor, Husmuttern: Johan Tjernell, johan.tjernell@husmuttern.se
Supervisor, MDH: Barrett Sauter, barrett.sauter@mdh.se
Examiner, MDH: Janne Carlsson, janne.carlsson@mdh.se
The following report describes a thesis work written by a student in the spring term 2021 at Mälardalens Högskola, as a final part of Bachelor of engineer in Innovation and Product Design. The aim of this degree project is to develop a product to satisfy the need to have a mailbox for grocery delivery. The product should be adapted for homes where it will be placed.
Methods of product development process has been used to carry out this degree project. The following phases were applied: planning, research and needs analysis, concept development, design study, detailed development and prototype development. The phases have been used to complete the project while answering the question:
- How can a refrigerated mailbox be designed in order to create value for the customer?
- What features are of value to include in a refrigerated mailbox design?
The result of this project is presented with CAD prototype as a final product. By following the process mentioned, the goal of designing a refrigerated mailbox has been achieved.
Acknowledgment
During this degree project a lot of help was received by different individuals that I would like to extend my gratitude to.
First and foremost, my supervisor from Mälardalens högskola Barrett Sauter who have been greatly helpful throughout this project. To always direct me in the right direction and help me stay focused on the goal of this project. As well as letting this project to be my individual process to do my way and to complete. Thank you as well to my examinator Janne Carlsson for always understanding and helping with this work. It was with his encouragements and kindness that much of hardships were lifted.
I would like to extend a big thank you to Johan Tjernell, supervisor from Husmuttern company. For making it possible to work on this project together with the company. Thank you for showing help when help was needed.
1 Introduction ___________________________________________ 1 1.1 Background ________________________________________ 1 1.2 Problem description __________________________________ 1 1.3 Goal and Purpose ____________________________________ 2 1.4 Delimitation ________________________________________ 2 2 Method ______________________________________________ 3 2.1 Product development methodology ________________________ 3 2.2 Planning methods ____________________________________ 4 2.2.1 Milestones ________________________________________ 4 2.2.2 GANTT-chart ______________________________________ 4 2.2.3 Assignment description ______________________________ 4 2.3 Benchmarking _______________________________________ 5 2.4 Method of user survey _________________________________ 5 2.4.1 Interview ________________________________________ 5 2.4.2 Observation _______________________________________ 5 2.5 Method for product specification _________________________ 5 2.6 Quality Function Deployment (QFD) _______________________ 6 2.7 Idea and concept generation methods ______________________ 7 2.7.1 Brainstorming _____________________________________ 7 2.7.2 Six Thinking Hats __________________________________ 7 2.8 Methods for evaluation and concept selection _________________ 8 2.8.1 Concept screening __________________________________ 9 2.9 Data collection ______________________________________ 9 2.9.1 Technical aids _____________________________________ 9 3 Theoretical background __________________________________ 11 3.1 Human factors _____________________________________ 11 3.2 Anthropometric measurements __________________________ 12 3.3 Ergonomics _______________________________________ 13 3.4 Biological factors ___________________________________ 13 3.5 Refrigerator _______________________________________ 14 3.6 Materials _________________________________________ 14 3.6.1 Granta Design ____________________________________ 14 4 Current situation analysis ________________________________ 16
5 Implementation _______________________________________ 17 5.1 Planning _________________________________________ 17 5.2 Research and needs analysis ____________________________ 18 5.2.1 User survey ______________________________________ 18 5.2.2 Assignment description _____________________________ 18 5.2.3 Identification of opportunities _________________________ 18 5.3 Concept development ________________________________ 19 5.3.1 House of Quality __________________________________ 19 5.3.2 Idea generation ___________________________________ 19 5.3.3 Concept generation ________________________________ 19 5.3.4 Concept elimination and evaluation _____________________ 19 5.3.5 Concept development _______________________________ 20 5.3.6 Concept selection __________________________________ 20 5.4 Detailed design study ________________________________ 20 5.4.1 Target group _____________________________________ 20 5.4.2 Design study _____________________________________ 20 5.4.3 Prototype design __________________________________ 21 5.5 Detailed development ________________________________ 22 5.5.1 Detailed design ___________________________________ 22 5.5.2 Material selection _________________________________ 22 5.5.3 Surface treatment _________________________________ 22 6 Results ______________________________________________ 23 6.1 Planning _________________________________________ 23 6.2 Observation _______________________________________ 23 6.3 Identification of opportunities (results) ____________________ 25 6.4 House of Quality ____________________________________ 26 6.5 Concept generation __________________________________ 27 6.6 Concept screening ___________________________________ 28 6.7 Design study _______________________________________ 28 6.8 Design ___________________________________________ 31 6.9 Final product architecture _____________________________ 33 6.10 Material __________________________________________ 43 6.11 Surface treatment ___________________________________ 43 6.12 CAD drawings ______________________________________ 43 7 Analysis _____________________________________________ 44 8 Discussion ___________________________________________ 46 9 Conclusion ___________________________________________ 48 10 References __________________________________________ 49
11.2 Appendix _________________________________________ 51 11.3 Appendix _________________________________________ 52 11.4 Appendix _________________________________________ 53 11.5 Appendix _________________________________________ 54
Table of figures
Figure 1: Method used in the project __________________________________ 3 Figure 2: Gantt-chart (projektmallar.se, 2017) ___________________________ 4 Figure 3: House of Quality Ullman 2018 _______________________________ 6 Figure 4: Six Thinking Hat method ___________________________________ 8 Figure 5: Concept screening Matrix (Ulrich & Eppinger, 2014) _______________ 9 Figure 6: Specific storage temperatures (James, et al., 2016) _______________ 14 Figure 7: Product information (Klarstein, 2019) _________________________ 16 Figure 8: Cardboard prototype of product _____________________________ 21 Figure 9: Observation Willy:s pick-up station __________________________ 24 Figure 10: Male sitting 1006 mm and 949 mm __________________________ 29 Figure 11: Female sitting 949 mm and 892 mm __________________________ 29 Figure 12: Male standing 11779 mm and 1902 mm ________________________ 30 Figure 13: Female standing 1673 mm and 1789 mm _______________________ 30 Figure 14: Product sketch _________________________________________ 31 Figure 15: Types of door handles ____________________________________ 32 Figure 16: Product inside door _____________________________________ 34 Figure 17: Product inside door empty ________________________________ 35 Figure 18: Product inside door delivery _______________________________ 36 Figure 19: Product outside door ____________________________________ 37 Figure 20: Product outside door open ________________________________ 38 Figure 21: Nameplate ____________________________________________ 39 Figure 22: TouchPad ____________________________________________ 39 Figure 23: Inside door ___________________________________________ 40 Figure 24: Sealing strip __________________________________________ 41 Figure 25: Sealing strip close up ____________________________________ 42
Table 1: Anthropometric measurement book by Bohgard (2010) ______________ 12 Table 2: Compilation of consisting materials in modern regrigerators, Lindman 2012. _______________________________________________________ 14 Table 3: Implementation method phases ______________________________ 17 Table 4: Opportunitets ___________________________________________ 25 Table 5: List of problems _________________________________________ 26 Table 6: Value specifications of user needs _____________________________ 26 Table 7: Concept combination table __________________________________ 27 Table 8: Concept Screening table ___________________________________ 28
List of abbreviations
The following will provide with description of a few repeatedly used words.
CAD
:
Computer-Aided Design.
CES
:
Cambridge Engineering Selector.
Mailbox :
A box at or near residence for the
1 Introduction
In the following chapter, the problem description is addressed as well as the purpose and the goal of this degree project. The intended target group is specified, the delimitation is mentioned.
1.1 Background
This following report was carried out to describe the work process of the degree project. The degree for Bachelor of Engineering program in production and product design, at Mälardalens university. Applying previous knowledge gained from the program, it is expected to carry out this project independently.
The project was performed with the house developing company Husmuttern AB, with the aim to develop a product to meet the needs of the residents of the company´s future accommodation. The product is to be used as a mailbox for delivery of food and packages. The box will have the qualities of a refrigerator to keep the food safe for a while until the delivery is picked out. The company´s aim is to build such a product at each townhouse.
1.2 Problem description
The Swedish public health authority announced strict national regulations from December the 14th, 2020. General guidelines were launched, which meant obligation
on a society level to take measures to prevent the spread of Covid-19. In these recommendations it is advised to avoid big gatherings and to only hang out in small circles, due to the high risk of spreading the infection to others. Small circle refers to a few close people to be in contact with, otherwise it is recommended to keep distance to other individuals. Avoiding social contexts reduces the risk of the Covid-19 spread but this has resulted in many people feeling lonely. This was acknowledged by the Swedish Public health authority (Public health authority, 2021).
Due to current situation many people are staying inside at their homes to follow the recommendations. This has led to great need of new adaptation in the society, among other things the delivery of goods to homes. It is relevant to assume that these
adaptations will be current even after the pandemic. Partly there will be new
pandemics in the future, but partly our behaviour has changed after seeing the benefits of new routines. Saving e.g., time and petrol on not having to go shopping. The task of this degree project is to develop a box for each home that can be used to receive grocery food and items. To facilitate the process of receiving the groceries at home even while the individual is not at home. Equipping the box with refrigerating qualities will fulfil the aim of keeping the food fresh. Studies and research of human factors and ergonomics will be conducted to guaranty maximum user satisfaction of the device.
1.3 Goal and Purpose
The goal with this degree project is to develop a product that can improve the quality of life for people in need of this product. Within the timeframe of this project the product will be presented in the form of a visualized prototype. Another goal is to show the necessary requirements for the engineering degree.
To achieve the goal the following questions will be answered:
- How can a refrigerated mailbox be designed in order to create value for the customer?
- What features are of value to include in a refrigerated mailbox design?
1.4 Delimitation
In this degree project the delimitation is not to optimize the technical function of the product. A finished product will not be produced, rather the focus will be on the design, products function, developing and prototype. Technical components will not be designed rather information will be provided. Examinations of how technical supplies will perform will not be investigated. A further delimitation will be the costs of production of the product and the cost of the components. This will also imply that the product will not be production adapted. The product will be visualized and not produced. The following process will bring forth a concept and is limited to phase 3 detailed development.
2 Method
The following chapter describes and deals with the different methods used to carry out the project. The method follows the product development process that is based on Ulrich & Eppinger (2014) product development process. The process will follow the phases shown in figure 1 and comprises the five first steps. The order of methods also reflects the order in which they were implemented. This chapter begins with product development methodology and continues with the methods used for planning, user research, development of idea and concept and finally result evaluation.
Figure 1: Method used in the project
2.1 Product development methodology
A product development process is the sequence of activities or steps that are
performed to fulfil a specific purpose. This process is usually performed by companies to understand, design and commercialize a product. A well-detailed and well-defined development process entails a quality-assured final product as well as coordination within the project members. Structure for who does what in planning, management and identification of problems. Ulrich & Eppinger (2014) divided the product development process into the following phases: planning, research, concept development, system level design, detail design, testing and further development as well as production start-up (Ulrich & Eppinger, 2014).
Planning phase is the first phase which is started before the approval and the start of the project. The aim of this phase is to contribute with a strategy and specification. That includes a description of the product, the product´s target market, business goals and finally basic assumptions, limitations and requirements. During the concept development phase, the target group´s needs are identified as well as product alternatives, that meet requirement, are generated and evaluated. Concepts are
selected for further development and testing. When the concept selection is completed the product is divided into subsystems and components. This phase is called
development or design at system level. After comes the detailed design phase where the product can be specified. Such as the geometry, materials and tolerance for the components of the product. Testing and improvement phase includes the testing of early built prototypes of the product. This phase is to test if the product does fulfil the target group´s needs before the product is examined in the production start-up phase (Ulrich & Eppinger, 2014).
2.2 Planning methods
The purpose of planning is to create an overview of the project as a whole. The methods used will provide a systematic structure in which the order of different tasks and goals to be achieved. Planning creates a realistic schedule and implementation phases that contribute to create a flow in the process of work in the project.
2.2.1
Milestones
The milestones are intermediate goals to be achieved during the project process. In a project milestones present reconciliation and control stages for overviewing,
controlling and following of the development process. The milestone plan should be kept simple to manage to divide complex plan into several smaller plans. This way it is easier to communicate how the project is to be implemented by taking one
milestone at a time and assess what activities need to be performed to achieve it (Tonnquist, 2021).
2.2.2
GANTT-chart
A GANTT-chart is a frequent used method to arrange schedules for a project. The diagram shows bars of the time frame of the project on the x-axis. The activities to be carried out during that period are stacked on the y-axis. The GANTT-chart visualizes the activities in relation to the schedule. Different activities can run in parallel but have different time frames. There may also be dependencies between the activities, which refer to that one activity must be terminated or in the process in order for the next to begin. It is important to highlight and identify the relationships for the activities that are connected, parallel or sequential in the GANTT-chart (Hallin & Karrbom Gustavsson, 2019).
Figure 2: Gantt-chart (projektmallar.se, 2017)
2.2.3
Assignment description
The assignment description is a document that is used to guide the product
development. The document summarizes the focus and direction to be followed in the project and what basic functions the product should perform. The assignment
description may contain information of product description, benefits, primary market, assumptions and limitations, and stakeholder (Ulrich & Eppinger, 2014).
2.3 Benchmarking
To successfully place a new product in the market it is required to first understand and study the competing market. The benchmarking method is used for deeper
understanding of the competing market and the already established products presented in it. The aim is to gain an overall picture of the competitors. In the process this method can also be used as a source for inspirations and new ideas for the product design and production (Ulrich & Eppinger, 2014).
2.4 Method of user survey
Identifying customer needs can executed using different methods. Users involvement methods are used to increase knowledge and highlights of problematic or deficient aspects of a product. Data gathering of the primarily market´s customer needs can be achieved using methods such as interviews and observation.
2.4.1
Interview
The interview method is used to collect information and data from individuals.
Interviewing involves, through a conversation with individuals, gathering information about opinions, experiences and thoughts. The interviewer can follow a structured, semi-structured or non-structured interview method. What differs the three categories of interview is the form of the structure that an interview follows. In general, in the case of quantitative data collection, structured interviews take place that follow pre-formulated questions that are to be examined. Qualitative data collection follows an unstructured form of interview. The first questions are structured to create a dialog with the interviewees. Later questions that can lead to open discussion are asked. This method of interviewing can be rewarding if the interviewer is able to lead the
questions and discussion in the needed direction (Bryman, 2018).
2.4.2
Observation
The observation method is a good alternative to use for a deeper understanding of how people actually act in given situations. The objective method aims to understand how one acts in their natural environment. How one actually acts and how one describes the way they act can differ. Therefore, observation is a method that provides clear and accurate reality of how the user behaves (Bryman, 2018). Aspects that are difficult to produce through question formulations can be revealed through observations. Where it is easier to pay attention to how the customer understands, uses and handles products, and what problems can arise (Ulrich & Eppinger, 2014).
2.5 Method for product specification
Product specification in a project means the description of what the product should do. This method is performed to specify the user needs. While the needs do not give clear guidance to how the product should be developed. It is required that after gathering information of user needs to establish a set of detailed and measurable specifications of what the product should do. A single specification consists of one measurable quality with one value. The value can be expressed in intervals, metrics, etc. (Ulrich & Eppinger, 2014).
2.6 Quality Function Deployment (QFD)
Quality Function Deployment (QFD) is a graphic technical method used in customer-centric quality development. The concept of the method is the relationship between needs and properties. In overall it converts the identified customer needs to technical product properties. This can be achieved by producing product specifications that meet customer need and where the specification is a measurable value (Ulrich & Eppinger, 2014). The customer-centric planning was developed In Japan in the end of 1960´s by the professors Shigeru Mizuni and Yoji Akao. Their aim was to create quality assurance method, “quality by design”, that can translate customer needs into relevant specifications in every step of the product development process (Bergman, 2020).
Customer needs and expectations, spoken or unspoken, is identified by collected analyses of customers behaviours. Capturing the customers’ requirements can be implemented with interviews, observations and surveys. Elements that are important for this method include benchmarking the competitors. Collecting data from
competitors provides with key factors of which customers’ needs are met and (Bergman, 2020).
The House of Quality matrix (HoQ) according to Ullman (2018) is an important product planning matrix of QFD. The matrix follows a house-shaped diagram built of information that can be viewed in sections as shown in the figure 3. The sections refer to the following. Who is identifying the customers and what is the customer needs.
Who vs. what is prioritizing the customer needs that are more important than others. Now and now vs. what stands for benchmarking. The specifications and technical
properties are the how. The correlation of specifications to customer needs are what
vs. how. Development of ideal target values is how much. Finally, the how vs. how is
the correlation of specifications (Ullman, 2018).
2.7 Idea and concept generation methods
Concept generation method is used to break down complex problems into simpler part problems. The aim is to reduce the likelihood of costly problems. Concept generation is not costly so there is no excuse for lack of accuracy and caution throughout this method (Ulrich & Eppinger, 2014).
2.7.1
Brainstorming
Brainstorming method is used during concept generation phase to internal concept exploring. Here personal knowledge and creativity are exploited to generate new ideas and suggestions. This probably is the most creative and unconditional phase
throughout product development. The purpose of the method is to generate as many ideas as possible by following four useful guidelines. First is to postpone decision which refers to the importance of not criticizing any ideas during the brainstorming exercise as this can prevent creativity. Second guideline is to generate as many ideas as possible, quantity before quality. During brainstorming many ideas that are
generated seem impossible, the third guideline means that these ideas that seem impossible should be welcomed. Last guideline is to use graphic and physical media such as sketches (Ulrich & Eppinger, 2014).
2.7.2
Six Thinking Hats
The Six Thinking Hats method was developed by Edward De Bono to bring about a more effective, focused and efficient thinking process. Each colour of a hat
symbolizes a character and have its own separate role. The purpose of this method is to systematically manage the individual consciousness and thinking to fit these six roles (The de Bono Group, LLC, 2012).
Description of each hat and their qualities can be read below.
The White Hat: This hat is for facts and right information only and symbolizes a discipline and a direction. Wearing this hat calls for imitation of the computer. The individual is expected to act neutral and therefore impartial and does not hold opinion or support information. “The facts, just the facts”.
The Yellow Hat: This hat symbolizes the sun or sunshine. Values
optimism, positivity, opportunity and brightness characteristics. The hat is also constructive and strives for things to happen, therefore
generative. The hat calls for positive search in benefit and value of the process.
The Black Hat: In the opposite to the yellow hat, the black hat is negative. The thinkers of this hat offer negative judgment and remarks of risks along the process. Wearing this hat, the individual will locate errors that might potentially occur with the method. This hat is
important to include, due to it´s effective critical thinking, as long as it is not overused.
Green Hat: The focus of this hat is mainly on creativity, possibilities and provocative ideas. A fundamental aspect of wearing this hat is to explore new alternative concepts and ideas. The hat allows for the opportunity to express new perceptions in the thinking process.
Blue Hat: The hat is symbolized with management and control to ensure the guidelines are followed. Wearing the hat implies organizing the way of thinking to better define and shape the subject in question. This method also summaries problems and put forward suggestions.
Red Hat: Signifies feelings and emotions as well as hunches and intuitions. The individual can express feelings such as disapproval without the need for logical basis to support or justify the emotion. Figure 4: Six Thinking Hat method
Using this method will allow for a deeper understanding of facts, feelings, process, caution, benefits and creativity. Each factor will be examined, considered and recognized on its own.
2.8 Methods for evaluation and concept selection
Concept selection is a process where generated concepts are evaluated in relation to identified customer needs. Relative strengths and weaknesses of few selected concepts are compared and taken to further examining and testing. Concept selection is the process where concept options are reduced, while not resulting in a clear dominating concept (Ulrich & Eppinger, 2014).2.8.1
Concept screening
The method is based on a method that was developed by Stuart Pugh 1980s and usually is called Pugh´s concept selection matrix. The purpose of the matrix is to improve and screen out concepts throughout. Every concept is set against
requirements to see how they are meet. On the upper section part, the concepts are entered and on the left side of the matrix the customer needs that are identified are entered. To use this matrix a reference concept needs to be put, which can be an older version of the product. Thereafter the concepts are compared and rated with +, 0 or -. The ratings stand for “better than (+)”, “equivalent to (0)” or “worse than (-)”. When all the concepts have been valued the three values are summed together. The summery is placed under each concept on the lower part of the matrix. The concepts are ranked with the received value, this is done to see which concept potentially stands out. This gives an opportunity to combine concepts of high ranks. The overview the method provides is important to reduce the number of concepts as well as improve existing concepts. (Ulrich & Eppinger, 2014).
Figure 5: Concept screening Matrix (Ulrich & Eppinger, 2014)
2.9 Data collection
The collection of data for this paper is based on study articles and books related to product and concept development. This was carried out for the sake of obtaining a theoretical frame reference. The theoretical data was collected with websites such as Google scholar and MDH library. Articles are required to be peer-reviewed to make sure they don’t hold any specific underlying agenda in the statement of their research. Therefore, Scopus and Ulrichsweb were used. Other data from users was collected through interviews and the survey.
2.9.1
Technical aids
CAD stands for Computer Aided Design that is widely used in the in the process of creation. This computer-program is used to modify, analyse and optimize the
construction designers. Using 3D, the program enables an efficient conceptualization and visualization of products in different planes with various precise measure tools (Saracar, M. et al., 2008).
3 Theoretical background
The design of the project in general is based on theories of product development processes. In this chapter a selection of theories is presented on which evolution of the final product is based.
3.1 Human factors
Human factors in product design have in the recent years increased in importance and prominence. In his book Designing Pleasurable Products Jordan says that the human factors are central for a successful design. The technology advances and production processes have reached a high level in the market and it is no longer a question of functionality or cost that is crucial. Rather the significant element for competitive advantages is the increasing awareness of human factors issues (Jordan, 2002). The phycologist Abraham Maslow describes the human needs hierarchy order through his human needs ladder. This hierarchal human need is viewed as the lower and higher needs. Maslow means that the human always strives to satisfy the higher needs after the lower needs (psychological need) are fulfilled. According to Maslow humans try to meet their needs in the following hierarchy: physiological needs, security and belonging needs and needs for self-esteem and self-realization (Jordan, 2002). Jordan (2002) means that the human needs hierarchy can be translated into human factors properties. The intention to contribute to product design process so the human factors can be meet either explicitly or implicitly. The order in which it can be
accomplished is by the product´s functionality, usability and pleasure. The products are expected to fulfil the functionality and usability the new challenge is the human factor which is pleasure or emotion. The pleasure-based approaches are not an
alternative of the usability-based approaches rather the pleasure approach is to create added value. The interaction and relationships with the products are central for the users to achieve a goal. This creates a challenge for the designers to understand human holistic which include a user-product interaction. Jordan mentions the four pleasures framework that is can be used to help evaluate how pleasurable a product is to be used and owned. This framework categorizes the four types of pleasures a user may seek in a product:
1. Physio-pleasure 2. Socio-pleasure 3. Psycho-pleasure 4. Ideo-pleasure
Physio-pleasures is the aspect with the physical use of the product. The pleasure that is derived from sensory stimulation. Socio-pleasure is derived from involvement and relationships with others. The cognitive pleasures of discovery, knowledge and intellectual satisfaction are psycho-pleasures. Finally, Ideo-pleasures can be aesthetically pleasing qualities the product possess or values that it embodies. An example can be that a product embodies values of environmental aspects and responsibility (Jordan, 2002).
3.2 Anthropometric measurements
Anthropometric is data that is used to access human dimensions. The considered data includes human dimensions, proportions, body position, ranges and range of motion. The majority of human body dimensions are statistically normally distributed, this implies that the dimensions of a population can be described by two measures: mean and standard deviation. When designing a product, the current anthropometrics data can be used. However, it is important to take into consideration that the human dimensions are in constant increase by ten millimetres every ten years. It is normal when using anthropometric measures to start from different percentiles, commonly the 95th percentile. Meaning that 95% of the normal population can fit in equipment or
places designed. The following are the concepts that needs to be considered when implying anthropometrics (Bohgard, 2010):
Design for the largest individuals
When designing a place, it is important to consider space for physical movement. Usually, the measurement for 95th percentile is used.
Design for the smallest individuals
For the matter of the actuators, the range dimensions are sufficient. It is appropriate to choose the 5th percentile.
Design for all
It is desirable for the design to be adjustable due to the fact that both men and women use the same product. Taking into account the 5th and 95th percentile is suitable.
Design for mean individuals
With the knowledge of human dimensions, movement and adaption to tools and environment have led to the flexible adjustments and settings possibilities increasing. For the economics and cost of the design it is more suitable to limit to target group.
Design for disabled and special populations
The ambition of the society is to create design suitable and accessible to group of different disabilities. To adapt special spaces for the person with wheelchair due to the fact of having different human dimensions.
In the table 1 anthropometric measurement in millimetre are divided into the 5th,
50th and 9th percentile. the data is for women and men from Swedish groups.
Men Women 5% 50% 95% 5% 50% 95% Body Length 1669 1779 1902 1562 1673 1789 Eye level 1562 1657 1778 1446 1553 1668 Shoulder height 1333 1459 1548 1252 1357 1468 Seat height 883 946 1006 832 892 949 Eye level in sitting 757 816 874 710 762 820 Shoulder hight in sitting 557 607 668 521 577 624
3.3 Ergonomics
Ergonomics is the subject area that is concerned with the knowledge of interaction between people and technique or elements of a system. Bohgard (2010) mentions in his book ergonomics as engineering art. People interact with products and machines which is a reason for why ergonomics is an important part of the engineering art. In the process of development, it is crucial to have an understanding of the individual’s capacity, limits and possibilities. Including ergonomics provides with benefits that can be drawn for all persons included in the system of product. The individual, organisation and the society as a whole. Considering ergonomics early on in the process provides with increased security, reduced risks and accidents as well as increased quality and satisfactory for the users (Bohgard, 2010).
Including ergonomic into design can provide with optimal fit between the individual and the product. Working method mentioned for engineers by Bohgard (2010) are:
• Holistic analysis of the individual • Connection between reality and theory • User-centred design
3.4 Biological factors
Bohgard (2010) mentions a variation of physical factors that can affect design and human capacities. Below a few of those factors will be addressed in this development process (Bohgard, 2010).
Hand grip
Design for handheld parts require to take into account three body part: back, upper arm and wrist. To achieve an optimal design, the form of the part signals the intended requirements of grip, force of use and method of use.
Age factors
Age is a factor that deteriorate bodily functions gradually such as muscle strength and oxygen uptake capacity. Much is due to muscle mass decrease the older the individual gets.
Line of sight
Most comfortable sight area for the individual under the horizontal line of sight is 15°. This level of observation recommended with the reflection of neck and head position.
3.5 Refrigerator
Refrigerators are common household devices that are used worldwide. The main function is storage of foods while keeping them in a cool temperature under long maintenance for safety and quality. Recommended refrigerator temperatures varies depending on where in the world it is used. The World Health Organization (WHO) recommends refrigerating food below 5°C after it´s cooked to decrease the chance of illnesses that are cause by unattended food left outside. Temperature is essential for reducing the chances of spoilage of the food, which can lead to causes of food poisoning. In the table below a few compartments mentioned and temperature ranges are recommended for each compartment (James, et al., 2016).
Figure 6: Specific storage temperatures (James, et al., 2016)
3.6 Materials
Modern refrigeration units consist in base of a compressor pumping system that help maintaining the colling. The cabinet consist metal, mainly steel. The structure of the refrigerator has an isolation to prevent the cooling from disappearing and is usually made out of plastic material. An example of a modern refrigerator model is from the manufacturer Electrolux model ERC37320W with weight of 868 kg. The table below shows the kin and percentage of material of the Electrolux model (Lindman, 2012).
Material Proportion in % Steel 45-65 Aluminium 1-2 Copper 1 Polyurethane insulation 8-12 Glass 2,5-3,5
Table 2: Compilation of consisting materials in modern regrigerators, Lindman 2012.
3.6.1
Granta Design
Materials can be examined in the software program Granta Design, formerly referred to as CES EduPack. The database provides with a deeper understanding of the
materials and the technical properties of these materials. As well as economic and environmental aspects (Granta Design, 2015).
3.6.1.1
Galvanization
The process of galvanization of steel enhances the corrosion properties by applying a protective zinc coating to the steel (Granta Design, 2015).
3.6.1.2
Stainless steel
Stainless steel is alloys containing at least 10.5% chromium. Excellent characteristics of the stainless steel such as resistance to corrosion and oxidation. Other properties of the steel are its mechanical properties such as high strength. The steel requires little to no effort to maintain (Granta Design, 2015).
3.6.1.3
PVC-elastomer
PVC is plasticized high molecular weight that can be used for rubber due to its UV, scratch and corrosion resistance (Granta Design, 2015).
4 Current situation analysis
The chapter will give a clear and object picture that describes the current situation in the market.
4.1 Klarstein Beersafe – refrigerator
Klarstein is a brand that designs quality refrigerators that are exclusively used for drink and food storage. The products vary from the capacity of 50 litres in volume to 201 litres in volume. Equipped with removable metal shelves that offers space for storage of bottles among other things. Due to their sizes the fridges can be easily removed to other places such as garden and outside areas. One of these products is Klarstein Beersafe XL that hold up to 60 litres. This product is popular due to the energy efficiency class A++- and it´s quiet performance. Wight of 24.5 kg and dimensions in millimetre of hight 635, width 470 and depth 440. Beersafe XL is installed with a temperature control setting for regulation of temperature as shown in figure 7. The range of the temperature control is from 0 which indicates off, to the highest which is 5 (Klarstein, 2019).
5 Implementation
The following chapters describe how the work was carried out. Each phase is described separately how they were carried out step by step. The result of each phase can be examined in the result chapter.
Table 3: Implementation method phases
5.1 Planning
For the sake of this project and the time frame given, planning was made. The product development process phases of Ulrich & Eppinger (2014) were used. The project would then be based on the phases with adaption to the specific problem formulation. To establish a time plan a schedule was made in the form of GANTT-chart with milestone of intermediate goals. This provided a perception of the activities and goals which need to be accomplished within a specific time or time frame as well as what activities are depended on previous activities completion. The chart activities are according to the different phases of Ulrich & Eppinger (2014). Each phase in the chart become an intermediate goal to complete before moving on to the next. The planning provides a detailed description of which steps in each phase is to be carried out. The GANTT-chart can be viewed in appendix 11.1.
Phase 0: Planning
•The planning phase provides an overview of this project in relation to time. How the project can be completed within the frame of time given.
Phase 1: Research
•The main aim is to understand the customer needs and what requirement specification can be established.
Phase 2: Concept development
•Developing ideas and generating concepts.
Phase 3: Design study
•Final design studies that to be concidered before moving on to the CAD design.
Phase 4: Detailed development
•Product design with the software program CAD. Stating measurements and specifying materials
5.2 Research and needs analysis
To gain fundamental information for the development of this product a research and needs analysis was conducted with the following steps.
5.2.1
User survey
To gather the knowledge necessary to complete this project, users’ needs must be identified. To accomplish a list of relevant requirements for users’ needs, different survey methods were conducted. The aim with the interviews and observation is to gather extensive information from the target group of the project. The interviews were carried out with a semi-structured method and the observations were performed
directly.
5.2.1.1
Interview
Interviews were conducted to gain a deeper understanding of what the user´s factors should be considered if using the product. The structure of the interviews was a semi-structured with a theme of relatively unsemi-structured questions. The questions serve as an interview guide with a certain structure. The questions asked were not too specific but formulated to answer the study´s question. To define the needs some hypothetical questions of different scenarios were asked. This was to provide a visualization of how the product was to be used and handled, and to investigating what important and possible functions the product would be performing. The age group that was
interviewed was around the age of the target group, i.e., seniors. There was no focus to interview a certain gender for this study. The questionaries can be viewed under the result chapter as well as the answered given.
5.2.1.2
Observation
Using the observation method is a complement for the interview survey. By observing users at public places further insight of how users behave in the natural environment is gained. The observation was conducted directly in daytime when the product is most used. Examining provided with different perspectives of possibilities that are otherwise difficult to identify. The user’s attitudes and emotions could be observed in an objective way. The information is later taken into consideration while listing customer needs and requirements specification. The observation can be viewed under the result chapter.
5.2.2
Assignment description
In this phase above all the information of the stakeholders, benefits, business goals and limitations were listed. This was step established by observing through research how the market is today and what goals are asked by the users. The points of the assignment description were each examined.
5.2.3
Identification of opportunities
Customer statements from interviews were collected and compiled into a list of requirements. Which they were ranked into order of relative importance for precision and clarity. The rank variation is between 1 and 5. From number 1 the highest to number 5 the lowest.
In this generation process a list of possible problems regarding the product use was listed as well. These errors were brought to attention during the interview with the
users. A list of possible problems was therefore compiled to ensure that they do not occur in the product.
5.3 Concept development
5.3.1
House of Quality
House of Quality was used with as a method for the customer focus. The customer needs and the specifications were scored with points for their relevance in regard to the needs. Specifications were given positive and negative signs depending on the strength or weakness correlation between them. The specifications were ranked depending on the result of points. The House of Quality execution can be viewed in the appendix 11.2.
5.3.2
Idea generation
After that the customer needs and requirements specification had been complied, concepts were to be developed to meet those requirements. To get inspiration a visit to Willy: s Hälla in Västerås was made. To examen different types of pick-up stations and understand the variations of the boxes. Benchmarking was used during this phase to generate further ideas for design and functions. Ideas of new concepts and possible products were then written down into lists. These lists were based on ideas from the visit but also from previous established requirements. The ideas that are relevant are taking forward.
5.3.3
Concept generation
After idea generation different ideas were considered of interest and later taking on as concepts. The concepts were then compiled and divided into different categories in one common list. To determine whether the ideas were to be developed the Six Thinking Hats method was used. The Six Thinking Hats method provided further acknowledgement for whether the concept hold the values for the requirements. Facts, benefits, caution, creativity, process and emotions are the main highlighted thinking patterns of the method. Using the method meant switching between characters in an effective way. Few concepts were to be combined with additional concepts of
consideration. To clarify the development, a concept-list was made into a combination table were four categories created multiple options of concepts. Brainstorming was among the methods used in this concept generation process to create options.
5.3.4
Concept elimination and evaluation
The evaluation and elimination of concepts are determined with first and foremost the concept screening matrix. Here decisions are made for whether a concept is evaluated for further development or to it should be eliminated. The pros and cons of each concept were examined, and the concepts were ranked. StorngPoint product was used as a reference. The comparison could be made due to the close observation of the StrongPoint product.
5.3.5
Concept development
Development opportunities were made using sketches to create a perception of the remaining concepts. Simple models and designs drawn to provide with an overview of the form and function capabilities of the product. Concept B and concept D were to be used in combination with the selected concept for development.
5.3.6
Concept selection
The concept selected was ranked to have the best qualities among the seven listed concepts. Using the Screening matrix to determine the outcome was proving to be the best method for this process.
5.4 Detailed design study
5.4.1
Target group
The primarily target group for this product is the individuals that the company will build the townhouses for. Mainly elderly and individuals with disabilities sitting in wheelchairs. The design of the product will focus on creating product with value that can satisfy the target users. Different human factors will be taking into account in this design process to ensure safety and ease when operating the product. These factors can be translated to design qualities of product management with focus on the target group´s limitation. Due to the target group´s age category and disabilities, decreased muscle movement and strength is a factor to considered in this design process.
Ergonomics for handle and different mechanical ways to open the doors are explored.
5.4.2
Design study
Within this phase the design of the product takes place. For the implementation of the design, sketching tools were used to better examen the environment where the product will be used. Sketches were drawing with the consideration for the human factors method and the anthropometric data table to establish a view of how the product will perform in the homes. Data from the anthropometric table of the 50% and 95%, while standing and while sitting, provided with a perspective of dimension that would provide best outcome for the target group. This conclusion is based on the research of human factors theory of product´s functionality, usability and pleasure. The
anthropometric table (see table 1) suggest the measurements for eye level for men and women while seated and while standing depending on which percentage group they fall under. The measurements taken creates added value for the individual, hence design pleasure. The target group of mainly elderly and individuals with disabilities in wheelchair. The box was placed at different hights from ground level for the 50% and 95% women and men of those seated and those standing. The aim with the design study is to provide with information to
5.4.3
Prototype design
After final concept was selected, following design initiatives were taken. In the design process sketches and ideas were developed into more concrete form. Prototype of cardboard 1:1 scale was built to gain real scale measurements. The cardboard
prototype was tested for size measurements with a paper bag from the ICA food store with hight of 45 cm, depth 17 cm and width 32 cm. A shelf was placed inside the box for measurements and testing. The aim of this prototype is to understand the real scale of the product and the box capacity in means of dimensions, see figure 8.
5.5 Detailed development
5.5.1
Detailed design
With the visualization program SolidWorks, the design of the final product could be built. Some sketch ideas were first formed to understand the shape of the product and the details. Inspiration from products in market were considered and further
adjustments were added. Through CAD design an exact picture of how the product form and details was presented. With the study of human factors to provide ergonomic measurements for the users of different background and muscle strength capacities. This product will be used in homes which also means that factors such as adaptation for the users viewing angle and placement of inside parts needs to be adjust for security when interacting with the product. Some other details to be added for
customer value is the visualization and aesthetics. The door on the inside of the home will be made see through with glass. This decision was evaluated to add value to the product with the aim for satisfy the Ideo-pleasure. The quality for the product to have a glass door is to allow the user to have a clear view of the product´s inside. Users will be able to know when a package has arrived without having to open the door. With the observations, concept screening and benchmarking it was arrived at that design of a digital locking-system is most suitable alternative in comparison to other methods. It will be designed to meet the needs of the product and the service it intended to provide with. Digital alternative will make the process easier for the individual that will deliver as well as maintaining a secure the package safety from the outside.
5.5.2
Material selection
Benchmarking was used to exam materials used by competing and similar products in the market. Materials of interest were taking into account for further investigation. The choice of material was partly based on the requirements specifications as well as specifications for refrigerators. It was important to choose materials that guaranteed the stability of the temperature of the box and that can prevent icing from forming inside. The placement of the product mean that the outside material must withstand the weather conditions. Hygiene and cleaning are important factors for the choice of material. The yield strength, recyclability and low weight are also taken into account.
5.5.3
Surface treatment
Taking into account the material and the possible production methods that can used. As well as research study of method and surface treatments that are used by similar products.
6 Results
In this chapter the results will be presented from the phases that were completed in the implementation. The chapter ends with a presentation of the end product of this degree project.
6.1 Planning
This degree project execution was completed in time due to following the Gantt-chart as a time plan as shown in appendix 11.1.
6.2 Observation
Through the observations of pick-up stations StrongPoint products that were conducted sometime in the early phases of this degree project. A few reflections presented themselves regarding the product. Behaviour, attitudes and functionality were the main three impressions of the observation. Behaviour of the users and the person packing the groceries into the pick-up stations. Most of the users already had a clear idea of what to be done and how to use the technology. The interaction attitudes of the users were calm, focused and productive. However, the functionality of the pick-up station varied depending on which box the user had to use. The boxes higher up were a bit of concern due to the hight, which seemed difficult for some. On the other hand, the lower rows did not seem practical for the users due to the need to bend and “drag” out the groceries. The pick-up station can be seen in figure 9 below.
6.3 Identification of opportunities (results)
The answers of the interviews are summarized into short answered below.1. Have you used the pick-up station method when doing grocery? Yes, first time during the pandemic.
2. What did you feel when picking up grocery from pick-up station? Using it saves time and is practical.
3. Would you like to have a box at your home for delivery? The answer was yes.
4. Would you like for the box to have a fridge function? Yes, that would make things easier when food is ordered. 5. Would you like for the box to have a password?
Yes, for security reasons.
6. Would you feel safe for the groceries to be delivered to your home? Yes, it would feel safe.
7. Would you prefer for the groceries to be delivered to your home over going to store?
Yes. It is very preferred for those who are living alone
8. What function or qualities would you prefer for the box to have? When using, installing?
Cleaning (easy to clean).
Secure (no one else should access the box) Temperature (for customer safety)
9. Would you prefer to control the temperature of the box? The answers were divided.
Summarizing the answers given from the interviews a list of opportunities was formed and ranked as shown in table 4 below.
Ranking Opportunities 1 Easy to use 2 Ergonomic 3 Size 4 Strong 5 Reasonable price Table 4: Opportunitets
The list was made during brainstorming and concept generation process to reflect on later in design.
List of problems
Difficulties regarding handling of product
Difficulties regarding usage of product Size related issues
Table 5: List of problems
Value specification of user needs in table 6.
Table 6: Value specifications of user needs
6.4 House of Quality
In the House of Quality table, the functional requirements in relation to customer requirements were ranked and valued. The competitors Beersafe and StrongPoint were evaluated regarding customer requirements. First place in ranking is the dimensions of the product with technical importance score of 84 and importance of 36%. Second in place is the force to open with technical importance score of 64 and importance of 27%. Placed third in the ranking is total weight with technical importance score of 45 and importance 19%. The main three of the functional requirements was then analysed for the development of the product.
Specification requirements Value
Total wight ≤ 20 kg
Price ≤ 6 000 kr
Yield strength ≥ 250 Mpa
Dimensions 50x50x65 cm
6.5 Concept generation
In concept generation various design and functions are listed, see table 7.
Design shape inside Design shape
outside Lock system on outside Other
Round shaped Round shaped Digital numerical digits (controlled with phone)
Lamps
Square shaped Square shaped Digital numerical digits (controlled with screen)
Thermometer
With open handle Keys Pullable Shelfs Inside door with no
lock system
Face recognition Door open outwards Fingerprint Divided into
two sections (one open space, one shelfs) Customizable sections (Build your own) Inside door glass Table 7: Concept combination table
Concept A: Round shaped outside and inside, inside door with no lock system, with
digital numerical digits (controlled with phone) lock system, lamps, thermometer, pullable shelfs, door open outwards and customizable sections.
Concept B: Square shaped outside and inside, inside door with no lock system, with
digital numerical digits (controlled with phone) lock system, lamps, thermometer, pullable shelfs, door open outwards and customizable sections.
Concept C: Round shaped outside and inside, with digital numerical digits (controlled
with screen) lock system, lamps, thermometer, pullable shelfs, door open outwards and is divided into two sections.
Concept D: Square shaped outside and inside, with keys as lock system, lamps,
thermometer, pullable shelfs, door open outwards with inside door glas and divided into two sections.
Concept E: Round shaped outside and inside, with fingerprint lock system,
thermometer, door open outwards and customizable sections.
Concept F: Square shaped outside and round shaped inside, with face recognition lock
(controlled with screen) lock system, thermometer, pullable shelfs, door open outwards and customizable sections.
6.6 Concept screening
In the matrix table below the concept that are to be continued with will be marked with Y as in yes. If not, then N stands for no and finally C is for combine. Concept G ranked the highest among other concepts, followed by concept D and concept B.
Table 8: Concept Screening table
6.7 Design study
The sketches for how the product will be placed for best user experience is presented in the sketches below. For the individuals in wheelchair the best option for men and women is when product placed 650 mm from ground level as shown in figure 10 and figure 11. For the women and men standing it is shown to be best outcome when is product placed 900 mm above ground level as figure 12 and figure 13.
Concepts Selection criteria Strong Point A B C D E F G Easy to use 0 - - 0 - - - 0 Ergonomic 0 + + - - + - + Size 0 - 0 - 0 - - 0 Strong 0 - - - + - - + Reasonable price 0 0 0 0 + - - - Sum +´s 1 1 0 2 1 0 2 Sum 0´s 0 2 2 1 0 0 2 Sum -´s 3 2 3 2 4 5 1 Net score -2 -1 -3 0 -3 -5 1 Rank 4 3 5 2 5 7 1 Continue? N C N C N N Y
Figure 10: Male sitting 1006 mm and 949 mm
Figure 12: Male standing 11779 mm and 1902 mm
6.8 Design
Given the results from design study i.e., the positioning of the product above the ground floor, the details on the product surface will be effect. After the specifications were made the product began to take a shape. Sketch ideas were made as shown in figure 14 and figure 15. With benchmarking sketch alternatives were made to deicide value of ergonomics and importance. Dimension suggestions were drawn as well as features.
6.9 Final product architecture
The architecture of the final design product is as shown above a result of a structured logical procedure. It would be impossible to end up with a product design like this without the structured process where every step gives information that adds up to the final design. The number of the unknown requirements and demands would simply be too many to handle if not all steps where included. The final product architecture can be viewed below in figure 16 to figure 25.
Figure 16 shows an inside of the house view of the product. The box with glass door, handle, temperature control screen and a shelf. Later figures 17 and 18 show the function of the product when it is empty, figure 17, and when there is a delivery, figure 18. The lamps on the two figures are different colours due to the added feature that indicates when there is a package or delivery. Figure 19 and 20 is view of the product from outside of the house. The product has a flatscreen with numerical digits for safety of opening the door on the outside. The design of the outer edges of the outside design follows the design of the door. This is designed for security, functionality and aesthetics.
Figure 21: Nameplate
6.10
Material
For the biggest part of the product the material that will be used is stainless steel. This material is viewed best due to its mechanical and other qualities. The material
stainless still can withstand difficult environments and consists of high mechanical properties. To enhance the steel galvanization can be used to add further corrosion properties. The rubber material for the sealing strip will be PVC which can resist corrosion and is light material to use.
6.11
Surface treatment
The materials that were chosen can be produced with die casting for metals and
extrusion for rubber as production methods. These methods give fine finish details and do not require surface treatment. Die casting is used when metal is molten and poured into the shape desired. Extrusion is when the material is pressed or drawn through a form.
6.12
CAD drawings
The CAD drawings and section views of the product can be seen in appendix 11.4, 11.5 and 11.6.
7 Analysis
The focus of this project is creating a refrigerated mailbox with design qualities and features that can add value. Human factors therefore were taken into account and included throughout this degree project. In this analysis section the product will be examined to be able to see how well the research questions were answered.
- How can a refrigerated mailbox be designed in order to create value for the customer?
- What features are of value to include in a refrigerated mailbox design?
Features
The design was made as neat as possible with straight lines and radius on the long sides. For comfort and stability, the doors measurements follow the outlined
measurements of the box. The inside door equipped with ergonomic oval bow shaped handle, centred in the middle of the outer edge. The materials on the inside door contain for the largest part of glass to add aesthetic value and purpose. Both of the doors have rubber isolation that protects the product and maintains a comfortable and easy use. The rubber isolation protects the door in case of large impact force. On the other hand, the door facing the outside is not designed with a handle, due to safety reasons. On the lower centre of the outside door a digital flatscreen is placed which inserted with a recess. The design of recess of the screen is to maintain the screen protected. Added to the screen design is an inclination of 15° to add value and simplify the interaction between the device and the individual using the screen. The inclination of 15° as mentioned earlier on in the theory, provides comfort to the neck and head and is recommended for the line sight. This design is to optimize the view ergonomically for the user.
Inside of the refrigerator box aesthetic design and minimalistic features are made. Block similar part protruding from surface made with straight grooves to place shelfs on. Creating more space for bags and placement other packages. The shelfs are adjustable and removable according to the user’s reference. For added value lights were designed on the top surface inside the box. Mainly to create pleasure for usage as well as functionality. The light changes between the colour white which indicates that the box is empty. When the light switches to red it mean that there´s a package inside. As for the size on the inside of the refrigerator box the design is aimed to create a spacious and robust form. The design is simplified and minimalized as to not limit the dimensions necessary. While creating an appealing expression of the shape with soft edges and straight lines.
The structure of the refrigerated box is designed purposefully with different sections to create a room for isolation to be placed in between. It is necessary to have an isolator between the inner and outer walls of the box to maintain the temperature inside. The structure of the extended hight on the top is for the sake of inserting the refrigerator machine. As for the ventilation and mechanical necessaries of the fridge will be fitted into the upper section of the box. A temperature controller was designed for functionality and added value when interacting with the product. With the ability to control the temperature the user will be more interactive with the product in an entertaining approach. The temperature will be displayed on a screen with the
selection from 1° to 5° as is in many refrigerators. Technical parts of the fridge such as the lamps, ventilation and temperature controller will have the chips or machines placed in the upper part of the box.
The total market cost of this product can be estimated to be around approximately 5 000 kr to 6 000 kr. This estimation is made with the help of benchmarking when examining other products with close similarities to the product developed. Klarstein Beersafe XL is sold in the market around 3 560 kr today. The product developed in this project shares similarities with Beersafe. However, not the added functions of security door and TouchPad which will be the main reason for the price difference.
