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Concept Development of

Weather Protection for a

Pay-ment Terminal

Konceptutveckling av v ¨aderskydd f ¨or en

betalningster-minal

Bachelor thesis, 15 hp, Product Development and Design, Spring 2019

Amro Abu-Zarour Dannio Nguyen

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ABSTRACT

The demand of smart solutions and automation of machines that can reduce human labor for improved efficiency and safety has been increasing in the recent years. In order to obtain competitive and sustainable products for the global market today, the products must be adapted to withstand various weather conditions. The products con-taining electronics are one of the most vulnerable in this context.

This bachelor thesis is the result of a project done at Malm ¨o University in cooper-ation with Dover Fueling Solutions. This thesis describes a product development pro-cess with a purpose to develop a design concept for an optional weather protection for a freestanding payment terminal. The goal of the project is to produce manufacturing documentation and a prototype. Later on, the scope of the project was extended due to an insight requirement governed by the Payment Card Industry Security Standards Council that the payment terminal needed to fulfill.

The final concept suggests a reformed design of the existing payment terminal and the addition of new components. An optional protection has been added to protect the card reader and the numeric keypad from rain, snow, moisture, salt spray, and gas fumes. A cover is also added to protect the receipt outlet from the mentioned weather conditions and chemicals. The developed components are optional, and the changes that have been done to the payment terminal has not affected the original design considerably. The cover to protect the card reader and numeric keypad can be opened and closed manually. It can also stay open by an electromagnet and be released when the payment terminal is idle.

The result of this project shows that the existing payment terminal can be weather protected with minor changes to its original design, and with the addition of the optional protection.

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SAMMANFATTNING

Behovet av smarta l ¨osningar och automatisering av maskiner som kan recudera m ¨ansklig arbetskraft f ¨or en f ¨orb ¨attrad effektivitet och s ¨akerhet har ¨okat i de senaste ˚aren. F ¨or att idag f ˚a konkurrenskraftiga och h ˚allbara produkter f ¨or den globala marknaden m ˚aste produkterna vara anpassade f ¨or olika v ¨aderf ¨orh ˚allanden. Elektroniska produkter ¨ar en av mest de utsatta vid detta sammanhang.

Detta examensarbete ¨ar resultatet av ett projekt utf ¨ort vid Malm ¨o universitet i samar-bete med Dover Fueling Solutions. Detta examensarsamar-bete beskriver en produktutveck-lingsprocess med syfte att utveckla ett v ¨aderskydd f ¨or en frist ˚aende betalningsterminal. M ˚alet med projektet ¨ar att ta fram tillverkningsunderlag och en prototyp. Omfattningen av detta projekt ut ¨okades vid senare skede till att ¨aven integrera ett insynsskydd i v ¨ader-skyddet f ¨or att uppfylla ett insynskrav som ¨ar satt av Payment Card Industry Security Council.

Det slutliga konceptet f ¨oresl ˚ar en ¨andring av den nuvarande betalningsterminalen. Ett valbart skydd framst ¨alls f ¨or att skydda kortl ¨asaren och det numeriska tangentbor-det samt ett skydd f ¨or att skydda urtaget f ¨or kvitto. De framtagna komponenterna ¨ar valbara och alla ¨andringar som har gjorts i betalningsterminalen ¨ar inte signifikanta och har inte p ˚averkat den ursprungliga designen avsev ¨art. Skyddet f ¨or kortl ¨asaren och det numeriska tangentbordet kan ¨oppnas och st ¨angas manuellt samt med hj ¨alp av en elektromagnet.

Resultatet av detta projekt visar att den befintliga betalningsterminalen kan vara v ¨aderskyddad med f ˚a justeringar av dess ursprungliga design tillsammans med ett v ¨aderskydd som ¨ar valbart.

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ACKNOWLEDGMENTS

This bachelor thesis has been performed as a project for the company Dover Fueling Solutions. As part of our bachelor’s degree program in mechanical engineering with focus on product development and design at Malm ¨o University. The project has been instructive, challenging but also fun and exciting. We would like to express our gratitude and appreciation to everyone who have helped us along the way to complete this thesis. Firstly, we would like to thank our supervisors Hanna Helgesson from Dover Fueling Solution, and H ˚akan Wernersson from Malm ¨o University, for supporting us through the project. We would like to direct special thanks to Kenneth Petersen and Caroline Wingren, colleagues at the company, for important inputs and for always giving us help and opinions when asked for.

Finally, we would also like to thank Pontus Bogert and Ove Aune for the manufac-turing of the prototypes.

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TABLE OF CONTENTS

1 INTRODUCTION 1

1.1 About Dover Fueling Solutions . . . 1

1.2 Problem Description . . . 1

1.2.1 Background . . . 1

1.2.2 Scope . . . 1

1.2.3 Purpose and Goal . . . 2

1.2.4 Delimitation . . . 2

2 BACKGROUND STUDY 2 2.1 Freestanding Payment Terminal . . . 2

2.2 ADA Standards for Accessible Design . . . 3

2.3 Payment Card Industry Security Standards . . . 3

3 METHODS 5 3.1 Concept Development . . . 5

3.1.1 Identifying Customer Requirements . . . 5

3.1.2 Product Specifications . . . 6

3.1.3 Concept Generation . . . 7

3.1.3.1 Benchmarking . . . 7

3.1.3.2 Brainstorming . . . 7

3.1.3.3 Brainwriting and Braindrawing . . . 7

3.1.4 Concept Selection . . . 8

3.1.4.1 Pugh’s Method . . . 8

3.1.4.2 Concept Scoring . . . 8

3.1.4.3 Intuition . . . 9

3.1.5 Material Selection for Product Design by Analysis . . . 9

3.2 Detail Design . . . 9

3.2.1 Mock-up . . . 9

3.2.2 Parametric Design . . . 10

3.2.3 Design for Thermoplastic Moldings . . . 10

3.2.4 Computation . . . 11

3.2.4.1 Dimensioning of Magnet . . . 11

3.2.4.2 Dimensioning of Snap Joints for Plastics . . . 11

3.2.4.3 Finite Element Analysis (FEA) . . . 12

3.2.5 Testing and Refinement . . . 12

4 RESULTS 12 4.1 Customer Requirements . . . 13

4.2 Establishing Target Product Specifications . . . 13

4.3 Principle Concept Generation . . . 14

4.4 Principle Concept Selection . . . 20

4.5 Concept Generation for Function . . . 22

4.6 Concept Selection for Function . . . 25

4.7 Concept Generation for Detail . . . 25

4.8 Concept Selection for Detail . . . 27

4.9 Selection of Material . . . 28

4.10 The Prototype . . . 30

4.10.1 Mock-up . . . 30

4.10.2 Parametric Design . . . 31

4.10.3 Design for Thermoplastic Moldings . . . 35

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4.11.1 Dimensioning of Magnet . . . 36

4.11.2 Dimensioning of Snap Joints . . . 37

4.11.3 FEA . . . 38

4.12 Setting Final Product Specifications . . . 39

4.13 Prototype Testing and Final Adjustments . . . 40

5 DISCUSSION 41

6 CONCLUSION 43

REFERENCES 44

A Principle Concept Generation A1

B Concept Generation for Function B1

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1

INTRODUCTION

The following chapters contain an introduction of the company, description of the prob-lem together with background description, purpose and goal, and delimitation.

1.1

About Dover Fueling Solutions

Dover Fueling Solutions (DFS) is a part of Dover Corporation, which includes sev-eral product brands like Wayne Fueling Systems, ClearView, Fairbanks, ProGauge, Tokhiem and OPW’s Fueling Management Systems [1]. DFS delivers end-to-end fu-eling solutions, from advanced fuel dispensing equipment and systems, to electronic payment systems. The company has customers worldwide and significant manufactur-ing presence with facilities around the world.

1.2

Problem Description

1.2.1 Background

The popularity of automation has been increased, especially in the recent years, and is applied to numerous human activity areas [2]. Utilization of automated machines can reduce human labor, and improve efficiency and safety [3]. We are today surrounded by automated machines, and they are being used by humans everyday, consciously, or unconsciously. Tasks that normally are performed by humans is being replaced by au-tomated machines in various forms. The machines that we observe each days can be traffic lights, coffee machines, payment terminals, and multiple more. Automation often requires electronic components, and these are sensitive to some weather conditions. To ensure that electronic components does not become dysfunctional and to not affect their lifetime expectancy, they should only be exposed to conditions they are intended for.

DFS, the company, has developed a freestanding payment terminal for outdoor use. The payment terminal can be placed on unmanned stations without canopy as weather protection. The payment terminal is mainly intended for the North America market, including Canada and the U.S. Thus, weather conditions such as snow, rain, and storm at low temperatures may occur. To prevent the electric components in the payment terminal from becoming dysfunctional, they must be protected to cope with the different weather conditions. The card reader and receipt printer are sensitive to water intrusions and there is a demand from customers to include an optional weather protection for the payment terminal.

1.2.2 Scope

The project is primarily set with a purpose to develop a concept of weather protection for the payment terminal. Although, there are concerns about whether the existing concept of the payment terminal fulfills PCI Standards [4]. Later on in the development process, the development team together with the engineering team at DFS, confirmed that the walls forming insight protection are not enough to fulfill the PCI Standards. This was not demanded by DFS but was implied by the development team. Thus, the decision is made to include a solution with increased insight protection which results in the concept development for detail.

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1.2.3 Purpose and Goal

The main focus of this project is product development and its processes. The purpose of the project is the development of a design concept for weather protection. The ex-isting concept of the payment terminal is analyzed to discover weaknesses in order to develop a new concept of weather protection. The goal of the project is to produce manufacturing documentation and a functional prototype for weather protection for the freestanding payment terminal. The final result shall be a functional prototype demon-strating all the protection functions of the solution.

1.2.4 Delimitation

In this project, delimitation has been made and the main focus of this project will adhere to the development of weather protection. Delimitation for this project is summarized by the following descriptions:

• The project does not include any economic aspects. • Any control and energy supply solutions are not included.

• Manufacturing of prototype(s) is done by the manufacturing department at DFS. The development of the concept is done without reflecting on the economic aspects. Any kind of electrical controlling system or energy supply for the affected concepts is not examined or described. Lastly, the manufacturing of the prototype(s) is outsourced to the manufacturing department at DFS and the manufacturing method(s) concerning the prototype(s) are not included in this project.

2

BACKGROUND STUDY

This chapter presents a description and analysis of the payment terminal, followed by descriptions of ADA Standards and PCI Standards.

2.1

Freestanding Payment Terminal

The payment terminal, shown in Figure 1, is still in the development phase. This pay-ment terminal is going to be placed along with different fuel pumps. It has a 12” touch-screen along with a touchpad to enable usage at a lower point for individuals with dis-abilities, for instance, wheelchair users. The payment terminal is configured with two different types of card readers which are a contactless payment reader and a traditional card reader that can read cards with chip and magnetic stripe. For security reasons, a camera will be implemented for surveillance purposes and will be placed above the screen between two speakers. On the lower part of the payment terminal, a barcode reader and a receipt printer are also placed.

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Figure 1: The freestanding payment terminal developed by DFS.

2.2

ADA Standards for Accessible Design

The developed concept of the payment terminal by DFS does comply with different standards with regards to the intended market. To ensure that the product can be used by everyone, the placement of the interactive components are at a certain height and depth.

Department of Justice (DOJ) formed the Americans with Disabilities Act (ADA) Stan-dard to ensure that none of the individuals with disabilities are discriminated. The ADA Standards states design requirements such as clearance and reach ranges. In short, in order to comply with ADA Standards, the interactive components of the payment ter-minal shall be placed at a height range of 380-1220 mm. The maximum reach depth of the components shall be at 510 mm [5].

In this project, the ADA Standards was taken into account through the development process. The compliance of the ADA Standards was not adversely affected by the future developed concept of weather protection.

2.3

Payment Card Industry Security Standards

The Payment Card Industry Security Council, PCI, has designed a set of security stan-dards to prevent credit card fraud. For the payment terminal to be approved by PCI, it has to fulfill these requirements. One of the several set security standards, to en-sure the security of when a payment is made, is how the insight is protected to where the cardholder is entering their code. General guidelines for designing to fulfill the in-sight requirements are provided in PIN Transaction Security (PTS), Point of Interaction (POI) [4].

For attaining a more simple visualization, the guidelines were translated into the shape of a cone, see Figure 2. The cone was placed in the middle of the ”5” key in the numeric keypad, and this is the reference point. When observing from the birds eye of view, the observation range for the cardholder is 90°, and the rest has to be protected from insight [4]. This is illustrated in Figure 3, and this is what represents the cut-out part in the cone in Figure 2. When observing from the bottom view, the observation angle that has to be protected from insight is 270°, see Figure 4.

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The payment terminal, in its original design, does not comply with standards con-cerning insight protection set by the council. In this project, the translation of the guide-lines into the earlier described cone was of help when generating and validating the new concepts for solving the terminals issue with insight.

Figure 2: The cone in red that visualizes what needs to be protected.

Figure 3: Bird’s eye view of the sample device of the numeric keypad. The angle the observation range for the cardholder, and is what is cut-out from the cone in Figure 2.

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Figure 4: Sectional drawing from the bottom view of the sample device of the numeric keypad. The angle described is between the lines of the observer’s eye and the refer-ence point.

3

METHODS

The methods that was used to accomplish the goal of this project are described in the chapters below. The methods has been divided into two sub-chapters, 3.1 Concept De-velopment and 3.2 Detail Design. 3.1 Concept DeDe-velopment describes the methods for generating and choosing a concept, as well as for choosing material. 3.2 Detail Design describes methods used to detail develop the chosen concept to create a prototype.

3.1

Concept Development

3.1.1 Identifying Customer Requirements

Identifying customer requirements is an essential part of the concept development phase. Customer requirements shall be expressed in terms of what the product has to do and in a way that offer maximum space to mainly generate and select product concepts [6].

Bodystorming is one of the User Experience Design (UXD) techniques, which is of help when identifying explicit customer requirements. The bodystorming method puts participants, in this project the development team, in an environment the solution is intended for to create empathy toward users. As the method builds an insubstantial connection between the users and the development team, the influence of the design can be more user-requirement centered [7]. The idea is to imagine what it feels like to be a user in a certain situation as if the product exists. Bodystorming can with simplicity

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be described as an act with a focus on physical interaction and design-thinking on-site in order to enhance understanding of the problem. The method is performed according to the following accounts:

• Build a group of at least two participants.

• Adopt a role and act as a user at appropriate environment. • Observe and create notes based on discussions.

The results from identifying customer requirements shall later be used to establish product specifications, generating product concepts and be the basis in concept se-lection [6]. In this project, the identification of customer requirements occurred in the following steps:

• Analyze and extract information from internal documents. • Perform a bodystorming session.

• Analyze raw data from bodystorming.

• Interpret all data in terms of customers requirements.

The goal was to identify latent, or hidden requirements and explicit requirements to ensure that the product’s focus was on the customer requirements to develop a common understanding in the development team. The customer requirements were largely independent and not tied to any specific product concepts.

3.1.2 Product Specifications

Product specifications comprise descriptions of what a product shall do. Customer re-quirements are generally expressed in a short and consist way which is usually immea-surable and not directly useful for the development team. All customer requirements need to be clarified and reformulated to product specifications to provide specific guid-ance about how to develop a product [6]. In other words, the product specification shall reflect the customer requirements but with measurable properties.

In this project, the product specifications was established twice. Once early in the development process, directly after identifying customer requirements, where the de-velopment team sets target specifications. Target specifications fulfill its purpose as a guideline and aspiration for the development team later in the concept generations and selections phase. In an ideal situation, all developed concepts shall meet the cus-tomer requirements but realistically some of them may fail or exceed the requirements. Therefore, the target specifications need to refined and adjusted for the chosen con-cept or concon-cepts. In this step, the development team analyzed the concon-cepts and set final specifications according to their constraints. The process of establishing target and final specifications entailed in the following steps:

• Create a list of properties with regard to customer requirements. • Rate the importance.

• Specify units for each property.

• Set ideal and marginal target values for each property. • Create a requirements-properties matrix.

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• Refine and set final product specifications.

Rate of importance was in the range of one to five, where one represents the lowest and five represents the highest. The requirements-properties matrix was for support and clarification of the context between the customer requirements and properties. The final product specifications were reviewed by representatives from the engineering and manufacturing departments to ensure and maximize customer satisfaction.

3.1.3 Concept Generation 3.1.3.1 Benchmarking

Benchmarking within concept generation is a form of an external search process that is used to identify existing products with a function that is similar to what is under development [8]. Benchmarking can be performed through searches on the internet and within the organization. This method is often a risk-minimizing and cost-effective approach for problem solving. Knowledge about how similar products and concepts to solve a specific problem can be gathered through this method [6]. In this project, this method was used to gather information of how similar problems, to what occurred during the development, was solved. In addition to this, the method was also used to gather inspiration to start the generation of concepts.

3.1.3.2 Brainstorming

Brainstorming is a method to generate new ideas and solutions to a given problem, verbally and/or in writing. This method resolves around five principles:

• State as many ideas as possible.

• The wilder or more creative the ideas the better. • Improve or combine ideas.

• Accept all ideas without criticism.

• Record all ideas for future consideration. [9]

This method was used to internally search for solutions to problems when generating new concepts.

3.1.3.3 Brainwriting and Braindrawing

In this project, a combination of the methods brainwriting and braindrawing was per-formed. Brainwriting and braindrawing are group-structured brainstorming methods that aims in generating new ideas and solutions for a problem. The group consists of around six participants that writes and/or draws three solutions to the problem on a piece of paper [8]. After five minutes the participants passes around the pieces of paper to each other. After this, each participant shall contribute with three new ideas to what the previous participant has contributed within under five minutes. This process is repeated until all the papers have been with all the participants [8].

This method forces equal contribution by all the participants in contrary to what brainstorming can do, where participants can dominate the idea generation [8]. In this project, this method was used in the early concept generating phase to generate a wide spectre of concepts.

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3.1.4 Concept Selection

The process of selecting a concept can be performed in various ways. A structured method to choose a concept is by comparing strengths and weaknesses with a product and evaluating them in relation to requirements, but they can also be chosen in other ways. The main goal here is to choose a concept that can be used for further developing [6].

3.1.4.1 Pugh’s Method

Pugh’s method describes performing a concept screening matrix that is used to com-pare and evaluate concepts opposed to a reference product [8]. The method involves listing selection criteria that are desired to be solved with the help of different concept options. The concepts are then compared to the reference product and rated a ’+’, ’0’ or ’-’ depending on if the concept:

• ’+’ = Meets the criteria better than the reference product. • ’0’ = Meets the criteria equally to the reference product. • ’-’ = Meets the criteria inferior to the reference product.

The reference product has the rating zero for all the different criteria. All the ratings are then summed up for each concept and the concept that has a neutral or positive total sum is chosen for further evaluation [8]. Pugh’s Method is the method that was used to sift down concepts and be the first step in choosing the final concepts in this project.

3.1.4.2 Concept Scoring

In this part of the product development process, the concepts are opposed to the needs and criteria to be evaluated. After this is done, one or more concepts are taken to further evaluation and development [6]. In order to carry out the concept selection, multi-voting was used internally within the development team as well as the weighting of pros and cons. To make the selection process objective, selection matrices were cre-ated. Selection criteria that are defined, as described in Pugh’s Method, were weighted against each other which makes it easy to distinguish which criteria are the greatest. All the criteria in the matrix were appointed a weight factor, and the sum of all weight factors were hundred percent. In order for the weights to be equally proportioned, they were graded opposing a reference object. The generated concepts were rated on a scale from one to five depending on how well they fulfill the criteria. The ratings are described as following:

• 1 = Much worse than the reference. • 2 = Worse than the reference. • 3 = Same way as the reference. • 4 = Better than the reference.

• 5 = Much better than the reference. [6]

When the concepts have been appointed ratings to each criterion, the ratings were multiplied to each weight factor and then added together to form a total sum. This resulted in a winning concept.

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To ensure that it is the winning concept and not chosen by chance, the criteria weights can be changed. This method is called a sensitivity analysis [6]. In this project, the weight factors and the ratings were changed to examine the sensitivity of the re-sult. This resulted in whether or not a certain score or weight factor has had more impact on the outcome than others. The criteria weights were changed according to how well the concepts fulfill aesthetic and functional needs. The winning concept with the highest total sum in the different concept scoring matrices was chosen for further development. This method was used to evaluate concepts equally to relevant criterion and for choosing which concept to continue developing.

3.1.4.3 Intuition

Intuition, as a concept selection method, is not as structured as Pugh’s method and concept scoring. Sometimes, if there are only a few concepts generated, other methods that are more time efficient can be used. One of these methods for selecting concepts, instead of performing a matrix, is that the concept could be chosen by its feel [6]. For this, trade-offs do not have to be used, and the concept just has to seem better than others to be chosen.

This method was used in this project when not enough criteria and concepts were set up to make a sufficiently detailed matrix.

3.1.5 Material Selection for Product Design by Analysis

Material selection by analysis is an analytic method for selecting a suitable material for a product and its associated components. The method is based on a fundamental understanding of the products development and its design [10]. In this project, the material selection was done accordingly to the following steps:

• Translation of the material requirements. • Analysis of the product/components involved.

• Identify material properties that determine performances.

• Screening of a database of materials and their properties, eliminate materials that fail to meet the constraints.

• Rank the remaining materials by their performances.

Material requirements are often expressed in non-technical terms that needs to be translated into properties to enable measurements of the performances. Analysis of the product/component(s) is for which materials are sought to set up the criterion for later ranking. Screening of a database of materials was performed by using CES EduPack to sort out and get an overview of the remaining materials relative to their properties such as density and Young’s modulus. CES EduPack provides a comprehensive database of materials with in-depth details and the materials’ usual applications [11]. The remaining material was sown with regards to availability and ranked by their ability. Lastly, the materials with the highest ranks were selected and assigned to the chosen concept.

3.2

Detail Design

3.2.1 Mock-up

In a manufacturing and design context, a mock-up has a purpose to facilitate the un-derstanding of geometries of a product. A mock-up can be described as a prototype

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at an early stage or a early revision. The mock-up(s) are made of simple and inex-pensive materials such as cardboard or similar materials [12]. It is usually made as a full-scale model to create a realistic perspective and provide a comprehensive picture of how the finished product can look like. In this project, to validate the design of the concepts and constitute a basis for later 3D modeling, mock-ups were created based on the generated sketches of the produced ideas.

3.2.2 Parametric Design

Parametric design, or more commonly known as computer-aided design (CAD), is the designation for designing using computer and software [13]. The technology, CAD, is used in a variety of engineering industries and areas. As some examples, the technol-ogy is used in product engineering, automotive engineering, and structural engineering. A CAD software enables drawings to be created in two or three dimensions (2D or 3D) using computer accessories such as keyboard and mouse. In addition to creating technical drawings both in 2D or 3D, the CAD software can be used to create digital prototypes that provide a basis for simulation and rendering [13]. There is a wide selection of CAD software and to name a few of them, there are SolidWorks [14], Creo Parametric [15] and CATIA [16].

In this project, SolidWorks was provided by DFS as the CAD software. Thus, the comprehensive digital prototype was developed using SolidWorks. Furthermore, the program Visualize by SolidWorks was used to render realistic images of the digital prototypes. Additionally, the digital prototype was used to manufacture a physical 3D model to evaluate the physical functions of the digital prototype.

3.2.3 Design for Thermoplastic Moldings

To use thermoplastic molding as the manufacturing method requires a certain amount of consideration for parameters in order to avoid manufacturing problems. In the hand-book User’s Guide to Plastic, written by Ulf Bruder, several design rules for thermoplas-tic moldings are mentioned. The rules are stated as below:

1. Remember that plastics are not metals.

2. Consider the specific characteristics of plastics. 3. Design with regard to future recycling.

4. Integrate several functions into one component. 5. Maintain an even wall thickness.

6. Avoid sharp corners.

7. Use ribs to increase stiffness.

8. Be careful with gate location and dimensions. 9. Avoid tight tolerances.

10. Choose a suitable assembly method. [18]

The design rules was taken into account in the process of designing the chosen concept in this project to avoid possible manufacturing disputes in the future.

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3.2.4 Computation

3.2.4.1 Dimensioning of Magnet

Center of mass is a point defined in proportion to an object or a system of objects. The point is the average position of points for all the objects in a system weighted accordingly to their masses and distances to a reference point [19].

When constructing mechanics, calculations like finding the equilibrium of torque, are often simplified when formulated with respect to a reference point [20]. The center of mass for a complicated system with different objects is calculated using the equation describing the basic definition of finding centers of mass. The center of mass can be found by the vector addition of the weighted position vectors which point to the center of mass of each object. Posterior to this, the sum is divided with the total mass of all objects in the system, see equation 1 [20]. In this equation, rgis the center of mass for an object, and mk is each objects’ mass.

rG=

Xrgimi mi

(1) To understand the least amount of torque needed for the magnet to be able to withstand, the calculation of the center of mass of the calculated object was critical. This method was used to find out where the center of the cover was to set up a torque equilibrium equation so that the torque caused by the own weight of the cover could be calculated.

3.2.4.2 Dimensioning of Snap Joints for Plastics

A simple way to mate different components with each other is using snap joints, espe-cially with suitable materials like plastics. Based on the design guide, Snap-Fit joints for Plastics, written by Bayer MaterialScience, snap joints are both an economical and a rapid way of mating components [21]. There is a wide range of snap joint designs and calculation principles. The most common type of snap joints is cantilever snap joints, shown in Figure 5, which usually have a rectangular cross-section. Other shapes of cross-section such as trapezoid, ring segments, and even irregular cross section may also occur [21].

In this project, a cantilever snap joint with a linear reduction of thickness was used to reduce the maximum strain on the material and minimize the amount of material. The thickness was linearly reduced to half of the determined thickness as shown in Figure 5. The following equations, equation 2, 4, and 5, was used to determine permissible deflection, deflection force and mating force.

y = 1.09 ∗ε ∗ l 2 h (2) Es= σ ε (3) P = bh 2 6 ∗ Esε l (4) W = P ∗ µ + tanα 1 − µtanα (5)

The permissible deflection y depended on the shape of the snap joint and the ma-terial’s permissible strain ε. Hence the reduction of thickness, the required permissible strain constituted one-half of the values presented in Table 13. Equation 4 was used

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to determine deflection force P , namely the required force to bend the tabs. In order to determine the deflection force, the secant modulus Es was obligated to be deter-mined beforehand using equation 3. Lastly, the determination of mating force W was calculated using equation 5.

Figure 5: A cantilever snap joint with linear reduction of thickness. Illustration taken from Snap-Fit Joints for Plastics by Bayer MaterialScience [21].

3.2.4.3 Finite Element Analysis (FEA)

To predict how a product reacts to real world forces, a Finite Element Analysis (FEA) can be issued [22]. FEA is a computerized method that is used to numerically solve engineering problems in the mechanical construction industry to analyze the strength of what is being developed [23]. It works numerically by calculating the predicted behavior by each element in a construction [22]. This analysis can show if a product bends, breaks or works the way as it is intended to.

In this project, SolidWork’s built-in module SolidWorks Simulation was used to im-plement the method [14]. The analysis resulted in how the construction reacts to un-usual interactions.

3.2.5 Testing and Refinement

With different kinds of testing, products can be evaluated and improved during the development phase [24]. A number of requirements affects numerous demands on the product, thus, in order to increase the quality of this project, a prototype testing shall be carried through.

In this project, the prototype testing took place at the facility of DFS, where misuse and assemble tests were performed to identify possible weaknesses of the construc-tion. Scenarios of misuse of the products were simulated by using bodystorming. The result from prototype testing were documented and later on used as the basis for cor-rection and reinforcement.

4

RESULTS

Results from the performed methods is presented below. Customer requirements, tar-get specifications, the generated concepts, and the prototype are presented. Later, the result of the selection of material for the components, and computation for dimensioning and analysis. Lastly, final specifications and result of prototype testing is presented.

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4.1

Customer Requirements

In order to identify explicit requirements that are necessary for interaction with the prod-uct, raw data was collected using the method bodystorming. To identify latent or hidden requirements, buyers’ and daily users’ inputs are required. The buyers’ and daily users’ input reveals in the form of formulated requirements in provided Product Requirements Specification (PRS) and Market Requirements Document (MRD).

The customer requirements that were considered to have the greatest importance are focused on ADA Standards and protecting sensitive parts from weather exposures. All requirements and their relative importance factor are shown in Table 1. The product itself should be adapted for tall, short and wheelchair users to maintain the accessibility of interactive components for all users. Furthermore, it should be easy to operate and offer the possibility to do regular service like changing paper rolls for the receipts. Accessibility for desirable electronics integration in the form of camera operation and second readers (NFC, Apple Pay, Tap & Pay) were also highlighted. The estimated product lifespan should at least be the same as the payment terminal. The main target markets are Northern America, including Canada and the U.S. Therefore, requirements of ability to operate at low temperature, ability to withstand rain, snow, ice, moisture, salt spray, and gas fumes are set. Companies on the market also require surfaces to add logos and their own color theme.

Table 1: Customer requirements and their relative importance factor.

No. Requirements Importance

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1 Adapted for tall people 5

2 Adapted for short people 5

3 Adapted for wheelchair users 5

4 Easy to operate 4

5 Maintain visibility of interactive components 3 6 Offer accessibility for optional second readers (chip keys, NFC, Apple

Pay, Tap & Pay)

2 7 Offer field serviceability without disrupting other parts 5 8 Offer possibility for future camera operation 4 9 Offer customizations for customers (logos, colours) 4

10 Offer long lifespan 4

11 Ability to operate at -40 °C 4

12 Ability to withstand exposure as rain, snow, ice, moisture and salt spray

5

13 Ability to withstand gas fumes 3

4.2

Establishing Target Product Specifications

The target specifications were set directly after identifying customer requirements and is shown in Table 2. The requirements-properties matrix shows the correlations be-tween requirements and properties in Table 3. The height from ground to the interac-tive area is limited to 1220 mm to meet the ADA Standards. The ideal height range is covered within 941 mm and 1220 mm to meet the ADA Standards and maintain a comfortable height of interaction for people with normal length (180 cm). The range of reach, the depth, is set to an ideal value of less than 400 mm.

In addition to meeting standards, it is important to retain or in the best way enhance the intuitive interactions of the interactive components on the payment terminal, such as numeric keypad, card reader and receipt outlet. If the product covers or prevents the interactive components to function without additional movement, it needs to have

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manageable mechanisms and visible instructions and labels. The 12” touch screen and the interactive components should be accessible at the users’ angle of view, which means that the users should not have to adjust the posture to use the touch screen and the interactive components. A vital function for maintenance is that the receipt printer needs to be maintainable in order to change paper rolls regularly. The best way to meet the requirement is to allow the receipt printer cover to open freely without disrupting other parts. The market demands customizability of the payment terminal. Thus, the product needs to be customizable or not cover the existing surfaces for logos and colors. To create a competitive product that can withstand rain, snow, ice, moisture, salt spray, gas fumes, and low temperatures, the product should be water and chemical resistant, rustproof, and functional at -40 °C. Temperature variations affect the material of the product in a certain way, therefore, the product should fulfill a comprehensive list of material requirements. The ideal lifetime of the product is also set to ten years due to the estimated product life of the payment terminal in the MRD.

Table 2: Target specifications with its relative importance along with marginal and ideal values.

No. Req. no. Properties Importance Units Marginal values Ideal values

1 1,2,3 Height from ground 5 mm 800 - 1220 941 - 1220

2 3 Depth (range of reach) 5 mm <510 <400

4 3,4 Manageable mechanism 5 Binary Yes Yes

5 4,5,6,8 Accessible at angle of view 4 Binary Yes Yes

6 7 Maintainable 5 Binary Yes Yes

7 9 Customizable 3 Binary Yes/No Yes

8 10 Lifetime 4 Year >5 10

9 11 Functional test at -40 °C 5 Binary Pass Pass

10 11 Material requirements 4 Binary Pass Pass

11 12 Rustproof 4 Binary Yes Yes

12 12,13 Water & chemical resistance 4 Binary Yes Yes

Table 3: Requirements matched with measurable properties.

1 2 3 4 5 6 7 8 9 10 11 12 Requirements Proper ties Height from g round Depth (r ange of reach) Visib le instr uctions and labels Manageab le mechanism Accessib le at angle of vie w Maintainab le Customizab le Lif etime Functional test at -40 °C Mater ial requirements Rustproof Water & chemical resistance

1 Adapted for tall people x

2 Adapted for short people x

3 Adapted for wheel chairs users x x x

4 Easy to operate x x x

5 Maintain visibility of interactive components x x

6 Offer accessibility for optional second readers (chip keys, NFC, Apple Pay, Tap & Pay) x 7 Offer field serviceability without disrupting other parts x

8 Offer possibility for future camera operation x

9 Offer customizations for customers (logos, colours) x

10 Offer same product life as the payment terminal x

11 Ability to operate at low temperatures x x

12 Ability to withstand exposure as rain, snow, ice, moisture and salt spray x x

13 Ability to withstand fuel fumes x

4.3

Principle Concept Generation

This concept generation was performed to find solutions to the main problem. Bench-marking was done to gather inspiration for how similar problems might be solved. This was performed through searches within the company and internet searches where words that revolve around weather protection, payment terminals, outdoor electronics,

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cover and the like were in focus. The searches results in a reference product, shown in Figure 6 and the rest is shown in Figures A1 to A9 in Appendix A.

The gathered inspiration through the benchmarking process is beneficial when start-ing the next phase, brainwritstart-ing. Due to the lack of participants within the development team for performing this method, three other colleagues took part in this method. The brainwriting results in different crude concepts generated, see Figures A10 to A14 in Appendix A.

The adaptation of these concept generation methods results in eight different con-cepts. The various concepts are presented in Figures 7 to 14.

Concept 1, as seen in Figure 7, shows a complete cover for the entire terminal. This cover is transparent and opens and closes automatically. It has a track in its anchor point which allows the point of rotation to move which w makes it possible for it open and close within its own place. It is transparent which enables visibility of the screen and other components while it is closed. Figure 8 shows concept 2 which is a fixed transparent protection for the numeric keypad, the contactless payment option (Tap & Pay) and the touch pad. It has a partly transparent front for interaction and design purposes. It has a small fixed protection over the receipt outlet to prevent the ingress of particles. Concept 3 presents a full roller shutter cover for the terminal, see Figure 9. A roller shutter is a type of shutter that consists of numerous horizontal slots that are hinged together. This is also automatic and opens when a user comes within range. Concept 4, see Figure 10, is a half globe that provides a fully transparent cover to the terminal. It has its point of rotation at the center of the globe which makes it open and close within its radius. This concept is also automatic and open when the user comes within range. Figure 11 shows concept 5 which is a solution that resembles as a transparent box that encloses the entire terminal. This concept has manually operated doors so the user has to open and close the doors manually. Concept 6, see Figure 12, presents a solution where the card reader has been relocated and is placed above the numeric keypad. When having the card reader and the numeric pad close to each other they can both be protected with one cover, which is in this concept a transparent cover that can open and close. This concept has also, as in concept 2 in Figure 8, a small protection for that makes the opening for the receipt printer small to prevent the ingress of particles. Concept 7, shown in Figure 13, is an automated transparent cover that opens in a rotational and vertical motions. This cover protects all the components except the screen when it is closed. Figure 14 shows concept 8, which has similarities with concept 7, see Figure 13. This transparent cover is automated, but it opens in a vertical motion. It covers all components of the terminal.

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Figure 6: Sigma Outdoor Payment Terminal [25]. Clear cover for outdoor payment terminal.

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Figure 8: Concept 2, a fixed protection to protect the numeric pad, the contact less payment option, and the touch pad.

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Figure 10: Concept 4, a half globe that rotates at its center which provides a full cover for the terminal.

Figure 11: Concept 5, a concept that resembles a box that encloses the terminal with manually operated doors.

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Figure 12: Concept 6, a concept that suggest a new location for the card reader, a cover that opens and closes the numeric pad as well as the card reader and a receipt outlet cover.

Figure 13: Concept 7, a concept that protects the different components, except the screen with a automated cover.

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Figure 14: Concept 8, an automated cover that that protects all the terminals different components.

4.4

Principle Concept Selection

When choosing a final concept, it is important that all generated concepts are evalu-ated equally. Selection criteria were derived from the previously determined properties in Table 3. Posterior to this, the concepts were opposed and compared to the prod-uct Sigma OPT (Sigma Outdoor Payment Terminal) [25], see Figure 6, in a concept screening matrix, see Table 4. This product, was used as a reference product because of its similarities and the same area of function as the existing payment terminal. This resulted in four promising concepts that was measured in concept screening matrices. In Table 5, the different concepts are rated one to five according to how they meet the criterion. To ensure that the winning concept has not been chosen by chance, the criteria weights are changed in two new matrices. The changes in the matrices was changed with focus on aesthetics in Table 6, and with focus on function in Table 7.

The three concept scoring matrices result in the same winning concept, see tables 5, 6 and 7. The winning concept was the concept that has the highest total score in the majority of the matrices, and this was concept 6.

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Table 4: Concept screening matrix with Sigma OPT [25] as a reference product.

Concepts

Selection Criteria C1 C2 C3 C4 Sigma OPT [25]

(reference) C5 C6 C7 C8

Protection against snow and ice + 0 + + 0 + + + +

Protection against rain and salt spray + 0 + + 0 + + + +

Convenient height - - 0 0 0 - + - 0 Convenient depth + + + + 0 - + - + Ease of use 0 0 0 0 0 - - 0 0 Intuitive interactions 0 - - 0 0 0 0 0 0 Screen visibility 0 + - + 0 0 + 0 0 Ease of maintenence 0 - - - 0 - 0 - -Customizability + 0 + 0 0 + 0 0 0

Maintain design language + - - + 0 - + + +

Durability - 0 - - 0 - - - -Ease of manufacture - 0 - - 0 - - - -Sum ’+’s 5 2 4 5 0 4 6 3 4 Sum ’0’s 4 4 2 4 12 2 3 4 5 Sum ’-’s 3 4 6 3 0 6 3 5 3 Net Score 2 -2 -2 2 0 -2 3 -2 1 Rank 2 7 5 2 4 5 1 6 3

Continue? Yes No No Yes Combine No Yes No Yes

Table 5: Concept scoring matrix without manipulated weight factors.

Concepts

C1 C4 C6 C8

Selection Criteria Weight Rating Weighted Score Rating Weighted Score Rating Weighted Score Rating Weighted Score

Protection against snow

and ice 15.00% 5 0.7500 5 0.7500 4 0.6000 5 0.7500

Protection against moisture,

rain and salt spray 15.00% 5 0.7500 5 0.7500 5 0.7500 5 0.7500

Convenient height 3.75% 2 0.0750 5 0.1875 5 0.1875 3 0.1125 Convenient depth 3.75% 1 0.0375 3 0.1125 5 0.1875 5 0.1875 Ease of use 10.00% 5 0.5000 5 0.5000 4 0.4000 5 0.5000 Intuitive interactions 7.50% 3 0.2250 3 0.2250 4 0.3000 3 0.2250 Screen visibility 7.50% 3 0.2250 3 0.2250 5 0.3750 3 0.2250 Ease of maintenence 5.00% 3 0.1500 2 0.1000 5 0.2500 1 0.0500 Customizability 2.50% 4 0.1000 3 0.0750 3 0.0750 3 0.0750

Maintain design language 10.00% 4 0.4000 3 0.3000 4 0.4000 3 0.3000

Durability 10.00% 2 0.2000 2 0.2000 4 0.4000 2 0.2000

Ease of manufacture 10.00% 2 0.2000 2 0.2000 5 0.5000 2 0.2000

Total score 3.6125 3.6250 4.4250 3.5750

Rank 3 2 1 4

Table 6: Concept scoring matrix with focus on aesthetics.

Concepts

C1 C4 C6 C8

Selection Criteria Weight Rating Weighted Score Rating Weighted Score Rating Weighted Score Rating Weighted Score

Protection against snow

and ice 7.50% 5 0.3750 5 0.3750 4 0.3000 5 0.3750

Protection against moisture,

rain and salt spray 7.50% 5 0.3750 5 0.3750 5 0.3750 5 0.3750

Convenient height 2.50% 2 0.0500 5 0.1250 5 0.1250 3 0.0750 Convenient depth 2.50% 1 0.0250 3 0.0750 5 0.1250 5 0.1250 Ease of use 5.00% 5 0.2500 5 0.2500 4 0.2000 5 0.2500 Intuitive interactions 15.00% 3 0.4500 3 0.4500 4 0.6000 3 0.4500 Screen visibility 15.00% 3 0.4500 3 0.4500 5 0.7500 3 0.4500 Ease of maintenence 2.50% 3 0.0750 2 0.0500 5 0.1250 1 0.0250 Customizability 7.50% 4 0.3000 3 0.2250 3 0.2250 3 0.2250

Maintain design language 20.00% 4 0.8000 3 0.6000 4 0.8000 3 0.6000

Durability 5.00% 2 0.1000 2 0.1000 4 0.2000 2 0.1000

Ease of manufacture 10.00% 2 0.2000 2 0.2000 5 0.5000 2 0.2000

Total score 3.4500 3.2750 4.3250 3.2500

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Table 7: Concept scoring matrix with focus on function.

Concepts

C1 C4 C6 C8

Selection Criteria Weight Rating Weighted Score Rating Weighted Score Rating Weighted Score Rating Weighted Score

Protection against snow

and ice 20.00% 5 1.0000 5 1.0000 4 0.8000 5 1.0000

Protection against moisture,

rain and salt spray 20.00% 5 1.0000 5 1.0000 5 1.0000 5 1.0000

Convenient height 6.25% 2 0.1250 5 0.3125 5 0.3125 3 0.1875 Convenient depth 6.25% 1 0.0625 3 0.1875 5 0.3125 5 0.3125 Ease of use 10.00% 5 0.5000 5 0.5000 4 0.4000 5 0.5000 Intuitive interactions 2.50% 3 0.0750 3 0.0750 4 0.1000 3 0.0750 Screen visibility 2.50% 3 0.0750 3 0.0750 5 0.1250 3 0.0750 Ease of maintenance 7.50% 3 0.2250 2 0.1500 5 0.3750 1 0.0750 Customizability 2.50% 4 0.1000 3 0.0750 3 0.0750 3 0.0750

Maintain design language 2.50% 4 0.1000 3 0.0750 4 0.1000 3 0.0750

Durability 10.00% 2 0.2000 2 0.2000 4 0.4000 2 0.2000

Ease of manufacture 10.00% 2 0.2000 2 0.2000 5 0.5000 2 0.2000

Total score 3.6625 3.8500 4.5000 3.7750

Rank 4 2 1 3

4.5

Concept Generation for Function

This concept generation was performed to find solutions to how the chosen concept will function. The focus here was on how the cover shall open and close and how the receipt outlet cover should be fastened. The methods used for generating concepts in this concept generation was benchmarking and brainstorming.

As described, concept 6 suggest a new location for the card reader, a cover that can open and close to cover the numeric keypad and card reader, and a receipt outlet cover. The benchmarking is done through various internet searches and searches within the company’s database with words as, and similar to ”hinge” and ”open-close systems”. This results in a variety of solutions gathered, see Figures B1 to B6 in Appendix B.

Individual brainstorming was later performed where three concepts are generated. Concept 2.1 is a concept that is inspired by the snap-hinge concept in the Helix series within DFS, see Figure 15. The concept, see Figure 16, suggests a track that allows the cover to be slid in place, and then snapped in place by extrusions designed to permit the cover to rotate freely while maintaining its point of rotation. The snap, together with the track, prevents the cover from jumping out of its position. To stay open, this concept uses an electromagnet that activates when the cover opens to the fullest. The electromagnet is implemented in the original design of the payment terminal, and a magnetic metal bit is implemented in the cover. A cantilever snap was applied to fasten the receipt outlet cover. The snap resulted in two cantilevers on the sides of the receipt outlet cover that snaps on inside the walls of the outlet for the receipt printer, see Figure 17.

Concept 2.2 is a concept that also offers a track and snap function. For removing and inserting the cover, the snap mechanism has levers that can manually be pulled in marked directions, see Figure 18. It is also in its fixed state hold the cover in place by its point of rotation. A cantilever snap was also applied in this concept to fasten the receipt outlet cover.

Concept 2.3, see Figure 19, is a concept that has a shaft which is screwed into a threaded hole. To rotate freely, the shaft is only be threaded a length that allows it to be screwed in and stay in place while surpassing the thread in the hole. A cantilever snap is also applied in this concept to fasten the receipt outlet cover. A cantilever snap is also applied to fasten the receipt outlet cover.

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Figure 15: A snap-hinge concept that is used in the Helix series within DFS.

Figure 16: Concept 2.1, a hinge and snap concept that is inspired by the snap-hinge concept in the Helix series within DFS.

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Figure 17: The cantilever snap implemented in the cover for the receipt outlet.

Figure 18: Concept 2.2, a concept that offers a snap-function manually operated by levers for the cover.

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Figure 19: Concept 2.3, a concept that has a shaft that is screwed in place.

4.6

Concept Selection for Function

To evaluate the concepts and make a fair judgment to each concept, the first applied method was a concept scoring matrix. Some of the selection criteria focused on func-tion that was used in the first concept generafunc-tion was used in this concept scoring matrix. A new criterion, which is ease of application, was also added to this concept scoring matrix. This criterion was derived from the MRD and aims at the ease of as-sembly. Only one matrix was performed, thus, there are only selection criteria focused on function that are relevant for these concepts. The winning concept is concept C2.1, see Table 8 for scoring of the different concepts.

The weather protection has to be optional. It is not optimal for the track and the snap joint for the main cover to be in the original design of the payment terminal. This is because it conduces to a great deviation from the design, and therefore, a slide-in body to replicate the inner walls is done to be the anchor point. This body is to be called the main body and has the sole purpose of replacing the inner walls as not to disturb the original design of the existing payment terminal.

Table 8: Concept scoring matrix for selecting how the cover shall open and close. Concepts

C2.1 C2.2 C2.3

Selection Criteria Weight Rating Weighted

Score Rating Weighted Score Rating Weighted Score Ease of application 32.50% 5 1.6250 2 0.6500 4 1.3000 Ease of maintenance 15.00% 5 0.7500 4 0.6000 2 0.3000 Durability 32.50% 4 1.3000 2 0.6500 4 1.3000 Ease of manufacture 20.00% 4 0.8000 4 0.8000 3 0.6000 Total score 4.4750 2.7000 3.5000 Rank 1 3 2

4.7

Concept Generation for Detail

This concept generation was performed to attain solutions for how to solve the insight problem with the current payment terminal. Individual brainstorming was applied in this generation for generating concepts. The concepts generated were done in light of the

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design guidelines. The transparent front needs to be partly opaque in order to cover insight from above. Concept 3.1, see Figure 20, is a concept of the cover that integrates opaque walls (PCI walls) with its partly transparent front. The transparent part of the front is maintained for interaction purposes. The opaque walls together with the opaque part of the transparent front solves the insight problem. Concept 3.2, see Figure 21, is similar to concept 3.1 but instead of fixed walls, this concept suggests walls that are mounted on the cover through hinges. These allows the walls to hang freely and fold out when opening the cover. When closing the cover, a stop is constructed that enables the walls to fold into their closed position. Concept 3.3, see Figure 22, suggest opaque walls that are integrated into the design of the payment terminal. This does not impinge on the design of the cover.

Figure 20: Concept 3.1, a concept that suggests fixed walls integrated with the design of the cover.

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Figure 21: Concept 3.2, a concept that suggest walls that folds out then opening the cover.

Figure 22: Concept 3.3, a fixed solution that is integrated with the payment terminal and does not affect the cover.

4.8

Concept Selection for Detail

The concepts generated does all solve the insight problem and the only thing that differs them is how they were designed, and how the interaction is with the rest of the payment terminal. For this selection of concept, the criteria in focus were how well the design of

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the concept maintains the design of the payment terminal, and that the interaction with the rest of the payment terminal is not disturbed. Instead of performing a matrix, the main concept was chosen by an evaluation of how the designing team felt that it fulfills the needs.

Concept 3.1 has a limited opening angle, thus its fixed walls, which limits the inter-action, and concept 3.3 does not maintain the same design of the payment terminal. That leaves concept 3.2 which fulfills all the needs. Based on intuition, the development team is united in which one to choose for further development, and that is concept 3.2.

4.9

Selection of Material

Requirements that affects material properties were reformulated to measurable prop-erties and presented in Table 9 and Table 11. Analyzes of components were made to ensure that none of the material requirements were neglected. Desirable properties like transparency for ease of usage in order to facilitate card and code entries are also taken into account. The importance of density, stiffness, elastic limit and resistance towards different fluid were identified for both plastics and metals by the completed analysis. In addition to meeting all the proposed requirements below, a number of gen-eral guidelines had been set. The gengen-eral guidelines when selecting materials were that the materials should be light, stiff, and easily accessible.

DFS has specific guidelines for assigning material for exterior plastic cladding de-tails and metal dede-tails. The criteria, shown in Table 10, were set for plastic materials in order to comply with the guideline. For metal details, there were two main criteria to take into account. The magnetism and the corrosive resistance were taken into account due to the function of the cover and the environments which the payment terminal will be exposed to. The materials presented in Figure 23 and Figure 24 fulfills both Stan-dard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing (UL-94 V2) [26] and the RoHS directive provided by European Commission [27]. In addition to fulfill the flame classification UL-94 V2 and the RoHS directive, the terials, except polyvinyl chloride, do remain form stable from -40 to +70 °C. The ma-terials are vandal proof, resistant to corrosive chemicals such as oil, petrol, ethanol, and diesel. The materials are also paintable and do pass charging tests according to Standard for non-electrical equipment for use in potentially explosive atmospheres (EN 13463-1) [28].

The results from the screenings of EduPack’s database in Figure 23 and Figure 24 shows overviews of the materials stiffness and density. The screenings were limited to plastics and elastomers, and metals and alloys due to consultation with representatives from the engineering department regarding material selection. The limitation to plastics and elastomers was based on the possible manufacturing technique as thermoplastic molding. Therefore, the available materials were examined and selected based on their performances and how well they meet the requirements. Available materials that are tested and commonly used by DFS for exterior plastic details today are polycarbonate (PC), acrylonitrile butadiene styrene/polycarbonate (ABS/PC) and polyvinyl chloride (PVC). For metal details, such as shafts and sheet metals, there are stainless steel (SS) with different grades. The available materials for shafts are SS AISI 303 and SS AISI 304. The suggested materials by the development team for sheet metal that are ferromagnetic are SS AISI 410 and SS AISI 430.

PC was assigned as the material for plastic details because of its overall perfor-mance in Table 10 and due to its properties in Table 9. As the material with the lowest density of 1195 kg/m3and the highest yield strength of 60.2 MPa, PC was considered to be the suitable material for the application. The assigned material for metal details was SS AISI 303 for non-magnetic applications and SS AISI 430 for magnetic applications

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due to their and properties in Table 11.

Figure 23: Material selection chart for plastics and elastomers. Generated using CES EduPack [11].

Figure 24: Material selection chart for metals and alloys. Generated using CES Edu-Pack [11].

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Table 9: Measurable properties of each material (for plastics and elastomers). Data taken from CES EduPack [11].

Properties Polycarbonate (PC) Acrylonitrile Butadiene Styrene/

Polycarbonate (ABS/PC) Poly Vinyl Chloride (PVC)

Density [kg/m3] 1195.0 1200.0 1390.0

Young’s modulus [GPa] 2.3 2.8 2.3

Yield strength [MPa] 60.2 57.6 41.4

Service temp [°C] -43 to 116 -48 to 77 -10 to 84

Transparency Optical quality Opaque Transparent

UV radiation Fair Fair Good

Water resistance Satisfactory Probably satisfactory* Satisfactory

Chemicals resistant Satisfactory Limited Probably satisfactory

∗ = between limited and satisfactory

Table 10: Rating and ranking of available plastic materials.

Criterion PC ABS/PC PVC

Form stable from -40 to +70 °C 5 4 1

Resistant to Oil, Petrol, Ethanol & Diesel 5 3 5

Impact resistant, Vandal proof (IEC 60950) 5 5 3

Resistant to water and salt 5 4 5

UV resistant (sunlight) 3 3 4

Transparency 5 1 4

Total 28 20 22

Rank 1 3 2

Table 11: Measurable properties of each material (for metals and alloys). Data taken from CES EduPack [11].

Properties SS AISI 304 SS AISI 303 SS AISI 410 SS AISI 430

Density [kg/m3] 7955.0 7970.0 7750.0 7720.0

Young’s modulus [GPa] 196.5 196.0 200.0 200.0

Yield strength [MPa] 257.5 578.5 293.0 295.0

Service temp. [°C] -273 to 925 -273 to 925 -73 to 800 -73 to 870

Ferromagnetic No No Yes Yes

Corrosion resistance Moderate Moderate Restricted Moderate

4.10

The Prototype

4.10.1 Mock-up

The mock-ups, shown in Figure 25 and Figure 26, were created to quickly evaluate and get a realistic perspectives of the concepts. The first mock-up in Figure 25 is based on the concept 3.1 which is a cover with integrated PCI walls. The first mock-up was made to examine the allowance of clearance with the cover open for the usage of the keypad and the card reader. The clearance results in a height of approximately 100 mm, which was determined as not enough and will likely make use difficult for the users. Therefore, the second mock-up based on concept 3.2, shown in Figure 26, was created. The second mock-up was evaluated and the concept 3.2 was considered to be the best solution, thus, the cover can be opened more and is not limited by the PCI walls.

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Figure 25: Mock-up of the cover with inte-grated PCI walls based on concept 3.1.

Figure 26: A mock-up based on concept 3.2.

4.10.2 Parametric Design

A comprehensive digital prototype of the final concept including all the complementary parts shown in Figure 27. The optional weather protection is mounted on the reformed design of the payment terminal. There are a total of nine different parts that constitute the whole assembly of the prototype for the optional weather protection, see Figure 28. The components are:

• Main body. • Main cover.

• Two 18 mm stainless steel shafts. • Two 13 mm stainless steel shafts. • PCI wall, right.

• PCI wall, left. • Printer outlet cover.

All the parts except the receipt outlet cover should be assembled beforehand and then snapped on to the payment terminal.

The track was constructed to lead the shaft to its point of rotation and allow it to stay in position while still being able to rotate. A stop was constructed to enable the PCI walls to fold in and out when opening and closing the cover, see Figure 29. In order to prevent the walls from not sliding on to the stop, it had been ensured that there are no flat surfaces in the contact between them. The cover should be led through tracks to then be snapped in place thanks to the snap-modules shown in Figure 30.

The main body is snapped into place with its edges, see Figure 31, in its designated place. The designated place for the main body in the payment terminal is shown in Figure 32. The receipt outlet cover, shown in Figure 33, was constructed to snap on the walls of the receipt outlet. The magnet should be placed at the top of the cover at the height of the rotation point. This was done in order for the magnetic plate to be drawn to the electromagnet which is be placed in the payment terminal. See Figure 28 for the placement of the magnetic plate.

The 3D-printed version of the digital prototype, shown in Figure 34, was manufac-tured by the manufacturing department at DFS. The 3D-printed prototype was printed in the material ABS/PC. The main body with its complementary components and the

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printer outlet cover is mounted into a display that mimics a part of the payment terminal. The placement of the printer outlet cover is not correct and only provisional for evalua-tion. However, the printer outlet cover is mounted at the same angle as it intended.

Figure 27: The comprehensive digital prototype with its complementary parts in a full assembly.

Figure 28: Exploded view of the comprehensive digital prototype with its complemen-tary parts.

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Figure 29: This picture is a detailed view on one of the tracks, one of the snap-modules, and one of the stop-modules in the main body.

Figure 30: The cover shall be led through the tracks and to then become snapped in place by the snap-modules.

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Figure 31: Snapping points on the payment terminal.

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Figure 33: Receipt outlet cover that snaps on the insides of the outlets walls.

Figure 34: The 3D-printed version of the prototype.

4.10.3 Design for Thermoplastic Moldings

To avoid manufacturing problems during thermoplastic molding, the design was created with regards to Bruder’s design rules. The concept was designed to allow disassem-bling for easier future recycling or replacement of parts. The snap-modules and the stop-modules are integrated with the main body to reduce the number of loose parts. All faces were drafted with at least one degree to make the release process of the molding possible. Also, all corners are rounded to avoid the risk of cutting and minimize stress concentrations. The tolerances in the technical drawings, shown in Appendix C, were set according to DIN 16742 and ISO 2768-mK to avoid tight tolerances.

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4.11

Computation

4.11.1 Dimensioning of Magnet

To dimension the magnet that should uphold the cover when opened, the center of mass for the cover was found. This was achieved through the process of calculating the center of mass for different objects in a complicated system. The different objects are marked in Figure 35, and the ferromagnetic metal bit shall be placed in origo in the same figure.

Thus, the system contains different objects with different densities, the masses were calculated as shown in equation 6. The equation 6 shows that the masses were calcu-lated through multiplying the objects volume V with its density ρ.

mi= Vi∗ ρi (6)

The materials used were Polycarbonate (PC) and Stainless steel 303, and their densi-ties were found using CES EduPack material database [11].

Dimensions needed to calculate the center of mass for each individual object are presented in Figure 35. The insight protection walls and the small handle have odd shapes and were therefore complicated to calculate. To facilitate the calculations the shapes were simplified to two triangles and a hemisphere, see Figure 35.

Data from calculating the individual objects are presented in Table 12. The results in the center of mass for the entire cover being located (¯x, ¯y, ¯z) = (0, 65.15, 0.49) mm. The torque affected on the magnet was calculated through a torque equilibrium equation as shown in equation 7 where M0is the torque affected by the own weight.

M0= 66.07g ∗ 10−3 ∗ 9.81m/s2∗ 65.15mm ∗ 10−3 (7)

This results in the amount of torque M0 needed to uphold the own weight by the cover is 0.042 Nm.

The magnet should also be able to uphold the cover when exposed to rain fall, snow, and if a user is to close the cover manually. The requirement that is dominantly dimensioning is if the user cloes the cover manually. That was why the factor three was multiplied with the amount of torque needed. This factor results in that the amount of force needed by the magnet is approximately 1.94 N.

Table 12: Calculation of the different objects centers of mass.

Object x (mm) y (mm) z (mm) m (g) xm (mmg) ym (mmg) zm (mmg) 1 58.30 20.00 -14.90 2.60 151.58 52.00 -38.74 2 -58.30 20.00 -14.90 2.60 -151.58 52.00 -38.74 3 -58.30 20.00 -1.50 1.03 -60.05 20.69 -1.55 4 58.30 20.00 -1.50 1.03 60.05 22.80 -1.55 5 0.00 49.41 0.00 33.56 0.00 1658.20 0.00 6 0.00 107.45 16.00 16.75 0.00 398.74 59.37 7 0.00 100.02 1.02 21.54 0.00 2154.43 21.97 Total 66.07 0.00 4356.57 0.78

Figure

Figure 2: The cone in red that visualizes what needs to be protected.
Figure 6: Sigma Outdoor Payment Terminal [25]. Clear cover for outdoor payment terminal.
Figure 9: Concept 3, a open/close system that uses the ”roller shutter” technique.
Figure 11: Concept 5, a concept that resembles a box that encloses the terminal with manually operated doors.
+7

References

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