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Executive Summary

The report summarizes the design process of Group 30 for the course Mech 463: Mechanical Engineering Design. The project aims to propose a solution for a problem statement posed by 123 Certification Inc. The project outlines the progress made in the Fall semester and provides a course of action for the semester ahead.

In this report, we included a problem statement chapter that outlines the requirements of the clients as well as the design parameters that need to be considered whilst conceptualizing the final design solution. The focal point of the project is to improve the aesthetics of the client’s welding simulator so as to device a solution that better replicates a real welding environment. One of the many challenges faced in arriving at an optimal design included the constraints that were prescribed for the project.

Once the problem statement and constraints were clarified, we generated a few conceptual design solutions as a result of team brainstorming. Our team came up with several concepts that provided a range of design solutions for the numerous simulator sub-parts including the sensor housing and the welding gun. Design solutions included the addition of a handle bar, the development of a storage space in the empty compartment of the sensor housing, material enhancements for improved product efficiency and marketability, ease of housing lid disassembly, product re-dimensioning and part weight modification. The detailed explanation of the manner in which these design changes will contribute to an improved design has been outlined in the concept generation chapter of the report.

One final design was ultimately arrived at and the team proceeded to develop detailed design drawings for the finalized conceptual design. CAD models for the final design can be found in the Detailed Design chapter of this report. This chapter also ventures into the material selection process for the design and the parameters that were considered in order to arrive at the final material choices. Our group decided to use PETP plastic for the welding gun handle, ceramic for the weld gun tip and acrylic for the sensor housing. The final design of the sensor housing with all the added features is attached in the appendix section for review. Furthermore, we ran a static analysis to analyze whether the sensor housing handle is able to support the weight of all the components inside the box. The results obtained indicated that the maximum von mises stress developed as a result of the applied load were still within the limit of stresses that the handle can support.

Acknowledgements

We are using this opportunity to express our gratitude to everyone who supported us throughout the course of this MECH 463: Mechanical Engineering Project thus far. We are thankful to the guidance given by our advisor, Prof. Micheal Kokkolaras as well as the class instructor, Prof. Damiano Pasini. We also want to thank our client for this project, 123 Certification Inc, specifically to Mr Claude Choquet, CEO of 123 Certification and Mr Benoit Rouillard, Director of Operations at 123 Certification. We thank you for the collaboration and assistance in helping us to reach near completion for this project. Also not to forget, Mr. Francois Ouellet Delorme, a master student in McGill working on a thesis related to this project and his supervisor, Prof. Frank Ferrier who is working closely with us to fulfill the objective of this project. We are really grateful to be granted the opportunity to work on this project as our final year design project in McGill University.

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Table of Contents Executive Summary ........................................................................................................................ 2

Acknowledgements ......................................................................................................................... 2

List of Tables .................................................................................................................................. 4

List of Figures ................................................................................................................................. 4

Introduction ..................................................................................................................................... 5

Problem Definition.......................................................................................................................... 5

Current Design ............................................................................................................................ 6

Client Statements / Requirements ............................................................................................... 7

Black Box Decomposition .......................................................................................................... 7

Quality Function Deployment..................................................................................................... 8

Literature review ......................................................................................................................... 8

Welding: .................................................................................................................................. 8

Arc welding: ............................................................................................................................ 9

Gas Metal Arc Welding (GMAW) ............................................................................................ 9

GMAW Arc Weld Simulation ................................................................................................. 10

Competitor ................................................................................................................................ 10

VirtualLogic Systems............................................................................................................ 10

Miller LiveArc ...................................................................................................................... 11

Concept Generation and Evaluation ............................................................................................. 11

Design Embodiment...................................................................................................................... 14

Material Consideration.............................................................................................................. 14

Prototype Manufacturing .......................................................................................................... 15

Welding gun .............................................................................................................................. 15

Nozzle ................................................................................................................................... 15

Tube head .............................................................................................................................. 16

Handle ................................................................................................................................... 16

Ceramic Filling ..................................................................................................................... 17

Sensor Housing ......................................................................................................................... 19

Sensor Box Static Analysis ....................................................................................................... 22

Conclusions/ Recommendations ................................................................................................... 23

Bibliography/References............................................................................................................... 24

Website Links ........................................................................................................................... 24

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Appendix ....................................................................................................................................... 25

Quality Function Deployment................................................................................................... 25

Gantt Chart ................................................................................................................................ 27

Concept Generation Sketches ................................................................................................... 28

Pugh Matrix .............................................................................................................................. 31

Final Design Sketches ............................................................................................................... 32

List of Tables Table 1: Client Requirements ......................................................................................................... 7 Table 2: Morphological Chart ....................................................................................................... 11 Table 3: Concepts Generated ........................................................................................................ 12 Table 4: Final Design Description ................................................................................................ 13 Table 5: Material Selection Criteria .............................................................................................. 14 Table 6: 3D Printer Specs .............................................................................................................. 15 Table 7: House of Quality ............................................................................................................. 26 Table 8: Gantt Chart...................................................................................................................... 27 Table 9: Pugh Matrix .................................................................................................................... 31

List of Figures Figure 1: Current ARC+ Lite model ............................................................................................... 6 Figure 2: Black Box Decomposition............................................................................................... 8 Figure 3 : Nozzle ............................................................................................................................ 15 Figure 4 : Tube Head ..................................................................................................................... 16 Figure 5: Handle ............................................................................................................................ 16 Figure 6: Exploded View of Welding Gun ..................................................................................... 18 Figure 7: 3D Model of Welding Gun ............................................................................................. 18 Figure 8: 3D Model of Welding Gun 2 .......................................................................................... 19 Figure 9: Locking Mechanism ....................................................................................................... 20 Figure 10: Isometric View Sensor Box .......................................................................................... 20 Figure 11: Hinge Mechanism ........................................................................................................ 21 Figure 12: Exploded View of Sensor Box ...................................................................................... 21 Figure 13: Stress Analysis ............................................................................................................ 22 Figure 14: Strain Analysis ............................................................................................................ 22 Figure 15: Sensor Housing Concept 1 .......................................................................................... 28 Figure 16: Sensor Housing Concept 2 .......................................................................................... 29 Figure 17: Welding Gun Concept 1 .............................................................................................. 29 Figure 18: Welding Gun Concept 2 .............................................................................................. 30 Figure 19: Welding Gun Concept 3 .............................................................................................. 30 Figure 20: Final Sensor Box Concept ........................................................................................... 32 Figure 21: Final Welding Gun Concept ........................................................................................ 33

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Introduction Welding simulation has been widely used in industry and welding school nowadays, with huge benefits by conserving material used for welding as well as saving time spent to set up the equipment and its risk-free for the user as well. For this project, McGill University collaborated with 123 Certification Inc to improve their recent model of welding simulator. The current challenges faced by 123 Certification is the current model is obsolete and improvements in sensors used would give competitive advantage for the company over their competitors.

Our team is in charge of improving the aesthetics of the simulator, improving the ergonomics and physical appearances of the components to imitate real life welding experience. At this point, we have gone through the problem definition and concept generation phases. We came up with a final design of both welding gun and the housing for the sensor through evaluation using tools such as morphological chart, quality function deployment, pairwise comparison chart and objective tree method.

In this design report, it will be broken down into several chapters of design processes namely; problem definition chapter, concept generation and evaluation chapter, design embodiment chapter, and detailed design chapter. In the problem definition chapter, the design problem is explained in detail with QFD, background information and competitor information. In this chapter, the problem is clearly defined together with the criteria for evaluation.

In the concept generation and evaluation chapter, methods used to come up with final design is listed and explained. Utilizing method such as Pugh Matrix and morphological chart, the evaluation of criteria listed from problem statement chapter is done to select the final design.

While in design embodiment and detailed design chapter, all engineering analysis used to formulate the final design is included such as CAD drawing including exact dimensions of both welding gun and sensor housing, material analysis, ergonomics design as well as bill of materials needed to create the prototype using the 3D printer.

Problem Definition Welding simulators that are available in the market nowadays are mostly non portable and expensive and uses different technology to track the movement of the welder in which the movement are restricted in some welding orientation. Thus 123 Certification proposed a new design by using electromagnetic sensor as oppose to LED or visual detection. Because of this, the company need a team of engineers to design a new housing that will contain the sensors and the pickups of the new proposed welding simulator model. Thus, for this project, our group’s main concern is improving the aesthetics representation of the welding simulator in order for it to be as close to real life welding environment. Our client also proposed that the material used to build the housing should not interrupt the working principle of EM sensors. In this problem definition chapter, we will further define the problem using several tools to rank important criteria needed to be evaluated.

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Current Design

123 Certification has assigned us the task of designing and delivering a prototype of a portable welding simulator based on the current ARC+ Lite model of simulator based on the existing technology developed by the company. There is a model available for testing at McGill.

Figure 1: Current ARC+ Lite model

The current design is a simple easily portable design consisting of a box, containing the field emitter of the electromagnetic sensor, and the handle containing the sensor that is supposed to replicate the welding gun.

The emitter is located inside a light, fairly resistant plastic container. The box is rectangular and its dimensions are roughly 50cm by 30cm with the emitter located at one end of the box. Outside of the box there are two plastic handles on the sides as well as a compartment to store the handle. The main opening screws of the box were made of plastic however the handle

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screws inside the container and the emitter screws were metal – which we would like to avoid in our design to avoid distortions in the electromagnetic field.

The box is connected to the handle that is supposed to replicate a welding gun in the simulation. The handle is fairly big and sturdy: it is one of our goals to make it look more realistic and professional. It is mostly made of plaster with only the conical-shaped end containing the three-coil sensor (3 x 1cm coils). Client Statements / Requirements Figure below shows the requirements that need to be achieved as discussed with both our group and the engineering team of 123 Certifications.

Table 1: Client Requirements Requirement Description Electromagnetic sensor Uses hydra sixense sensor Compatible Material Material chosen must not interrupt magnetic field produced by the

emitter Cost Effective Must be within the budget of ~$800 Improved Aesthetics Design must met market expectation in order to be presentable on

shelves Realistic Design The design of the gun must imitate real welding gun to enhance

welding experience Multiple Welding Configurations

Butt, T, Overlap and Pipe welding configurations

Ergonomic The users must feel comfortable while training to weld. i.e no restrictions in movements

Black Box Decomposition Black Box Decomposition involves outlining basic functions and organizing them so that one can clearly see the inputs to the given function and the outputs or by-product of the given function.

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Figure 2: Black Box Decomposition

Quality Function Deployment

QFD or HOQ is a strategic methodology of gauging the relative important of the attributes for the design. The HOQ additionally allows for different product that serve the same function in the market to be compared with one another. The HOQ is an excellent manner for designers to understand the priorities of the project so as to cater to the needs of the client without digressing from technicalities. The house of quality is attached in the appendix (Table7) section. Literature review Welding:

Welding is a method by which structures are created by joining pieces of metal or plastic through fusion processes.[1] Heat is an essential component in the creation of a weld and heating is achieved via open flames, laser lights, ultrasound or the generation of an electric arc.[2] The Bronze Age is recorded to have first adopted welding practices which later translated into iron tool construction by the Egyptians. Welding soon became the primary mode of iron structure construction for Blacksmiths in the Middle ages. But it was not until the use of open flames in the 19th century that major breakthroughs in welding were made. In 1881 Auguste De Meritens first implemented lead metal fusion via heat generated through an arc which later became the most popular welding practice in the 1890’s. Until the 20th century most welding practices consisted of heated pieces of metal being hammered to form an amalgamate by a process known as forge welding.[2] However, a number of other welding processes such as spot welding, seam welding, projection welding ,stud welding , submerged arc welding and flash butt welding came

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to rise along the 1900’s.[1] In modern times welding practices may be categorized into 4 broad disciplines:

1. Gas Welding is utilized largely for piping and tube repair work. It is usually operated in relatively low temperatures and find its application in the jewelry and plastic forming industry.

2. Arc welding is an expensive form of welding that primarily utilizes electric current to join parts.

3. Energy beam welding or laser beam welding is by far the fastest and most accurate welding technique but is subjected to high equipment costs.

4. Resistance welding is the most environmentally friendly form of welding that utilizes additional pieces of metal to join two metal parts. This process is however relatively expensive and cannot be utilized in all situations [3]

Welding does however have its limitations. Stainless steel cannot be welded as they crack

and distort when subjected to heat. Alloys are also incompatible to welding processes due to their indefinite chemical composition. Arc welding:

For this project, arc welding will be the form of welding that will be subjected to analysis. Arc welding is a form of welding that utilizes a welding power supply to create an electric arc between an electrode and a given base material in order to melt the metals at the sealing point. Arc welding can use either direct or alternating current. Arc welding can also either use consumable or non-consumable electrodes. The region subjected to welding is usually guarded by some type of shielding gas or vapor. These welding processes may range from being fully manual to fully automatic. A relatively high level of workmanship is required to produce good quality arc welds. Extended distances between the work piece and the electrode could lead to the formation of a weak and defective weld. In order to form a smooth and continuously weld one must invest a large amount of time, must have a lot of patience and must practice upon a significant amount of material.[4] arch welding has many forms such as: Gas Metal Arc Welding (GMAW), Gas Tungsten Arc Welding (GTAW), Flux-cored arc welding (FCAW),Plasma arc welding (PAW),Shielded metal arc welding (SMAW) and Submerged arc welding (SAW). Gas Metal Arc Welding (GMAW)

Gas Metal Arc Welding, also referred to as Metal Inter gas (MIG) is an automatic to semi-automatic process that consists of a consumable wire electrode and shielding gas that is injected via the welding gun. The power source for such a welding process may be direct current or alternating current. Metal transfer in a GMAW may be globular, spray, pulsed spray or short circuiting. GMAW equipment include a power supply, a shielding supply, a welding gun and a wire-driven system. Cooling is obtained by a water spray.[5]

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GMAW Arc Weld Simulation

In an attempt to time and cost of training welders a mixed reality structure has been developed to virtually simulate GMAW. This structure is composed of a forced feedback device, a head mounted display a motion tracking system and a welding torch. The simulator is built upon the empirical results of a number of weld tests. These systems may further advance into an audio tracking system moving into the future. The simulation is designed to run in real-time and this is achieved by means of a neural network which determines the shape, the orientation and the quality of the weld. The resulting weld bead of the weld is displayed on a screen. The simulations also record the weld progress and growing weld quality of the welder.[6]

123 Certification has developed a hands –on weld simulator that allows for multiprocess, multimaterial, multipass and multiposition welding. The simulator provides results on a welder’s performance by analyzing weld speed, weld distance and the depth of weld penetration. The company’s simulator consists of an electrode holder, a gun, a 6 DOF tracking system and a head mounted display. The simulation is designed to run in real time in order to help trainees assess the quality and shape of the weld.[7] Competitor

This section will analyze the products that is readily available in the market and will be used as a guidelines to innovate a new technology for welding simulation. The information were acquired from respective company corporate website. The products specification and technology is described and will be considered as a criteria to be used in our own product. VirtualLogic Systems

Virtual Logic Systems Pvt. Ltd. Was incorporated in 2006. The company focuses on developing products using Virtual Reality, Simulation and 3D Stereoscopic technologies. Their product that is competitive in virtual welding simulator market is called VIRTUAL WELD.

The VR based Welding Operation Training Simulator has been developed for the Gas Metal Arc Welding (GMAW). The welding torch is designed to replicate a real one with 6 Degree-of-freedom movement. The torch is attached to an articulated arm for accurate position tracking of the welder’s movement. For the welder’s head position, VirtualLogic uses visual

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detection by using a camera to track welder’s head for user’s perspective correction. The working area of the welder is manipulated with movable screen to access different angle of the part for different welding angle.

Miller LiveArc

Miller developed their welding simulator as a tool to teaching and performance-evaluation device. The product comes with a screen that monitor the progress of the welder performance in welding. It provides valuable feedback on welding technique for the users. It also comes with MIG SmartGun which can both be used for virtual simulations as well as live-arc weld training.

The MIG SmartGun is embedded with LED and tracked by a camera to accurately detect the movement of the welder’s arm. To manipulate the angle of the piece, a welding positioning arm is used to hold it at different angle and the tracking technology can be equilibrate accordingly.

Concept Generation and Evaluation The concept generation for this project is mainly done through brainstorming using

concept maps, reverse engineering, morphological chart and reverse engineering. After several concepts is generated, each team member works on a design that meet all required criteria and came up with a few conceptual design to later be evaluated using pugh matrix. Attached in the appendix is the concept sketch that we made during the brainstorming.

Table 2: Morphological Chart

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From this chart, we came up with few concepts such as follows:

Table 3: Concepts Generated Concept Color Description

1

Orange

Closest to original product. Acrylic box, with lid tighten by six plastic bolts. The hydra sixense is located at one end of the box, tighten by a plastic bolts on a plastic platform. The welding gun is made of acrylic with a goose neck shape. The tip of the gun is made out of plaster. Raspberry Pi board is chosen for this design

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Green

This design is made up of a rectangular hollow bow with a storage compartment next to the emitter, in order to store the T, butt and overlap configuration plastic models. It also has a small plastic fan on the side in order to avoid overheating inside The box opens and closes using a top lid that ‘clips’ on using little side hooks and slots that make the design easy to open and close. The box is here made of epoxy resin. The handle as well as the tip of the welding gun are made of PTFE plastic and the gun is goose-shaped. A compartment is molded inside the box that is separated from the storage space of the 4 models, that contains the electromagnetic emitter. It will use an Amtel board and will only have handles on each side of the box

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Blue

This concept relies on a rectangular box made of acrylic that will both have a compartment to store the T, butt and overlap shape models when the simulator is not used, as well as the electromagnetic emitter on the other side of the box. The emitter is attached to the box using four plastic bolts. The lid of the box is attached on one side with a plastic hinge. There is a small plastic locking system on the other side to ensure that the lid does not open during transportation. This lock is also indented so that the surface of the box remains flat during welding simulation. The handle is the one closest to the average welding gun, and is made up of two different materials: the handle is made of polyester plastic that will contain the necessary wiring and the tip is made of heavier plaster to recreate a more realistic weight distribution. The device features two handles: one on each side of the box, as well as a pocket to store the gun and a hook to attach the tube linked to the box and the gun. Finally this design uses a Freescale Kinesis microcontroller board.

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Yellow

The fourth concept is made up of a box whose size is reduced by half, based on the optimum emitter-sensor distance. There is a foldable table which, when unfolded, will support the welding shapes at the optimum emitter-sensor distance. The box, which contains the emitter is closed with a press-fit lid and the emitter is placed on a pre-molded compartment ensuring that it does not move. The box is made of PVC plastic material and the gun is made of PTFE plastic for the handle and ceramic for the tip. Its shape is based on an average actual welding gun. Outside of the box is a pocket for the welding gun that is opposite to where the tube is attached to the box allowing the tube to be rolled around the box when disposed, as opposed to hanging loose. Finally it uses an NXP control board.

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In order to evaluate the four designs, we used Pugh’s weighted decision matrix. Using the same weights that we used in the QFD for the different criteria that we considered. We used concept number 1, the closest to the current model of welding simulator as our reference and compared the other 3 for each criterion. According to the matrix, it is design no.3 that collects the highest number of points. Pugh Matrix can be referred to in the appendix section of this report. The sketch of our final design is also attached in the appendix section. Below is the description of our final chosen design for both housing of the sensor and the welding gun:

Table 4: Final Design Description

Item Description

Sensor Housing

Our selected design features a rectangular shaped box, whose size is determined by the optimal electromagnetic sensor to emitter distance. Inside the box, the emitter is located on one of the sides and occupies about a third of it. It is fixed to the frame using four plastic bolts: it is important not to use metal ones to avoid electromagnetic signal distortion. The rest of the volume of the box is saved as a storage space for the three welding configuration models: t, butt and overlap. a mold inside the box will be made to ensure that they are secure during transportation and won’t damage the emitter. The box is easily accessible with the top lid. The lid is connected on one side by a plastic hinge and acts like a door. When closed it is locked by a little plastic lock. The knob for this lock is carved inside to ensure that the surface of the box remains flat during the simulation. The box is made of acrylic, a sturdy plastic that will ensure durability of the product and is easy to manufacture

Welding Gun

The welding gun is designed to be very close with an average actual welding gun, both in terms of shape and mass. The handle is made of polyester PETP and the tip of the gun is made of plaster, a higher density material that will allow the product to replicate an actual welder made from metal (which we cannot use here). The microcontroller board is Freescale Kinesis, an inexpensive efficient and easy-to-use board. When stored, the welding gun fits into a pocket located on the side of the box that will prevent it to move. There is also a hook with which we can attach the tube to prevent it from laying loose. Finally, there are two plastic handles, one located on each side for portability purposes.

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Design Embodiment Material Consideration

Table 5: Material Selection Criteria

In order to function optimally, our model would need to successfully transmit and detect electromagnetic signals without occlusions and would need to exude robustness and cost sensitivity in design. In addition to these requirements the weight of the simulator weld gun would need to reflect the design of a real weld gun and the weight of the box would need to be minimized in the interest of maximizing design portability. Hence density, hardness and cost per kg. were outlined as parameters that would help us gauge the ideal material to be used in each of the 3 design sub components. It is also appreciable to note that all the material listed in the table above do not interact with electromagnetic signal and hence transmission and signal reception would occur without interference.

For the Welding gun handle we would require a high density material because we are trying to increase the weight of the current design to ergonomically better reflect a real GMAW weld gun. The hardness of the material for the Weld gun handle would also need to be high as this sub component was identified to be the most used and hence subjected to the most damage by continued use and accidents causing it to fall from considerable heights. The cost of the sub-component would need to minimized in order to improve the profitability of the model. PETP Plastic, Teflon, PEI and Acrylic were the different materials considered for the Weld Gun handle. As viewable in the table above, PETP Plastic with a density of 1.38 g/cm3, hardness of R 101 and cost per kg of $ 3.66 is an ideal material for the weld gun handle.

For the weld gun tip, hardness and high material density were prioritized and in order to meet this purpose Ceramic was chosen to be the ideal material.

Lastly for the material of the box, low material density and high material strength would need to be top priorities with cost sensitivity being a secondary property. Acrylic, with a density of 1.18g/cm3 and a Rockwell Hardness of R 120 would work ideally as the box material.

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Prototype Manufacturing

The chief manufacturing process that our group has decided to utilize for the production of our Weld simulator Prototype is 3D printing. Since most of the material selected for this design process is easily available in its powdered form, it is easy to produce a finished prototype using 3D printing technology. A disadvantage of 3D printing is that it is a relatively expensive manufacturing process. Blow molding of plastic would be a much cheaper manufacturing process to achieve the desired model. For our project however we are looking for manufacturing processes that are available within the McGill campus and thus 3D printing was resorted to. Going into the future, the mass production of the model would further weaken the strength of 3D printing as the ideal manufacturing process but for an initial prototype it is an ideal manufacturing process. For the purpose of our project, the Objet500 Connex 3D Printer will be used. It is a multi-material 3D printer enabling the manufacturing of large models - 500 x 400 x 200mm (19.7 × 15.7 × 7.9 in.). Using patented simultaneous multi-material PolyJet technology, the Objet500 Connex can 3D print models with up to 14 different materials in a single job including color and elasticity gradients with the finest precision amongst 3d printers (16 microns).

The printer provides a realistic rendering of the final product. The 3D printer is available in McGill School of Architecture

Table 6: 3D Printer Specs

Net Build Size 490 × 390 × 200 mm (19.3 × 15.4 × 7.9 in.) Layer thickness Horizontal build layers down to 16-microns (0.0006 in.) Build Resolution X-axis: 600 dpi; Y-axis: 600 dpi; Z-axis: 1600 dpi

Welding gun Nozzle

The nozzle is based on a 23/23F nozzle design by Tweco. Refer to the part number for the Lincoln P/N: KP1930-3. This Nozzle was ideal because its shape allowed for the largest volume of material as well as easy manufacturing. The nozzle, as pictured, is a cylinder topped with a cone, both of diameter 0.88 inches. The total length of this nozzle is 3-1/4 inches.

You will also find that this design of nozzle is common among welding guns used in practice; therefore our design will not differ aesthetically. In order to mimic the nozzle we also intend to maintain the same material colour.

Figure 3 : Nozzle

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Figure 5: Handle

Tube head The head tube is the piping between the nozzle and

handle. This part is specific to different welding guns in terms of length and angle of bend. The most common configuration on the market is the 6 inch, 60⁰, tube head. These dimensions very likely include the length of the nozzle.

Fortunately, since the nozzle is over 3 inches we can instead use a 4 inch, 60⁰, tube in our design. For design simplicity, and considering ease of assembly, we

maintain the diameter of the tube as that as of the nozzle. This continuity does not affect the realism of the overall designs since welding apparatus does appear the same in many cases.

The curvature in our design is entirely smooth as it would be in an actual welding gun. This best mimics the bending process for metal piping which would be a straight pipe that is heated and bent into an angle. Unfortunately the curvature of our design does not fully represent that of an actual design but will be sufficient for welding purposes.

In order to allow a filling to be added to the length of the tube we first reduced the thickness substantially in order to create more volume for the filler material. Under other circumstances this would reduce the integrity of the apparatus but since we intend to fill the empty volume with a tough material there should not be difficulty.

For practical assembly this piece comes in two halves. It is not clear in the design how the two halves are attached to each other but it can be simply described. As in toy making, the 2 parts are attached by forcing the pieces together. The pieces are held in place by snap fitting. Adhesive is used between the two pieces for permanent attachment. Handle

The handle is the part that needs to the most ergonomic in the design. In order not to over simplify the design we took into consideration the overall handle curvature and shape of cross-section. The handle cross-section initially appeared to be circular but was in fact a rectangular with rounded corners. The cross-section was not of consistent area and

increased towards the back. The front of the gun was also of much larger cross-section. Taking this into consideration, we can create a design that is close in appearance to a welding gun, so that the user will get accustomed to its shape.

Like the tube head, the handle also comes in two pieces for ease of assembly. The two halves are also snap-fitted together. In the event that the handle also has to have filler then the design would facilitate for this.

One additional feature on the handle is the button. The button design does not differ from that of the 123 certification design. This is because we found that this area of the design was in fact accurate. The main differences between the original handle design and ours is that our

Figure 4 : Tube Head

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design is much closer in size to an actual welding gun. The shape is mostly maintained, but the length and thickness are different. In addition, we intend to also change the weight of the handle to be higher, hence more suitable. Ceramic Filling

In order to increase the weight of the design, we have created some pieces made of ceramic to be placed inside the tube head and the nozzle. For the nozzle, we only put ceramic in the cylinder section because the sensors are expected to be in the cone section. The entire tube head is full of ceramic. Since the plastic casing is too light to mimic the weight of an actual metal welding gun our only option was to fill most of the volume with ceramic material.

There is room for ceramic within the handle, but since the layout inside the handle is not defined it is difficult to create a shape for ceramic filler to place inside the handle. Our prototype will most certainly include the ceramic parts in the design, including that of the handle, but we have to consult with 123 Certification on what direction to proceed in considering the handle. Our industry contact also has to approve of our entire design before we can proceed.

The final design of the welding gun is designed using SolidWorks. The dimension of the

gun follows a typical GMAW gun so that the aesthetics of the gun will appear more realistic and close to real life look of it. The exploded view of the gun is also shown in this section to show different part to be manufactured. The rest of the hollow space inside the gun is filled with ceramic to add more weight on the model. Using mass properties feature in SolidWorks, we got the rough estimate of the weight of the gun to be 0.402kg. There will also be a conduit that runs through the bottom of the welding gun handle that contains the wiring that will activate the trigger of the gun.

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Welding Gun Handle

Ceramic Filling

Figure 6: Exploded View of Welding Gun

Trigger

Figure 7: 3D Model of Welding Gun

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Sensor Housing

The box is a rectangular hollow cuboid. Its dimensions are 360x255x155mm. All the components are made of acrylic (including screws and bolts) since we want to avoid any metals in the design to avoid electromagnetic signal distortion. The inside of the box is divided into two: one half houses the electromagnetic emitter and the other half is used for storage of the welding coupons (T, butt and overlap configurations). The emitter is to be bolted to the bottom of the box using four pre-molded screws in the box. There is also a hole on one of the size where the tube that links the box to the welding gun is attached (the diameter of the tube is 3cm).

The lid of the box is attached by a simple hinge system that is located on one of the shorter sides of the box (where the emitter is placed): this will give easier access to the welding coupons’ storage area. The lid is secured by a locking system on the opposite side of the hinge. The lid is located under the surface of the lid to ensure that the surface remains flat when it is used for welding simulations. There are also two small plastic cylinders molded out of the lid that are used to secure the welding coupons in the upward position when they are being used.

There are two handles located on each side of the box in order to transport the box in a horizontal way if desired. These handles are also made of acrylic and are attached using plastic bolts. A pouch is located on the side that features the attachment tube to the welding gun. It is used to store the welding gun when not in use.

Conduit Insert

Figure 8: 3D Model of Welding Gun 2

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Choosing acrylic as a material, the box itself weighs a total of 1995.1 grams.

Figure 10: Isometric View Sensor Box

Figure 9: Locking Mechanism

Box Handle

Gun Holder

Sensor Platform

Conduit Exit

Welding Coupons Holder

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Figure 11: Hinge Mechanism

Figure 12: Exploded View of Sensor Box

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Sensor Box Static Analysis For the sensor box, we ran a static loading analysis with load contributed by all

components inside it (magnetic field emitter, welding coupons, material of the box, and welding gun) and supported by the handle located on each side of the box as shown in the diagram below (green arrows). This is simulating the box being carried by both handles with the welding coupons stored inside. A really fine triangular mesh is done all over the sensor box to analyze the stresses. The load is modeled as few distributed load on different location depending on the where each components is placed inside the box.

Figure 13: Stress Analysis

Figure 14: Strain Analysis

From figure 12 and 13, we can observe that the handle design is sturdy to support the whole weight of the box including the component inside it. The maximum von Misses stress applied is located at the hinge at value of around 5 × 105 𝑁

𝑚2The lid of the box shows a small stress applied at the hinge, provided that the lid is left halfway open. The green area shows that the stress applied on that section is not critical, so, it is therefore neglected. We are overall very satisfied by the design of the box and the choice of components, which will visibly make our product a sturdy, durable one.

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Conclusions/ Recommendations From this report, we outlined the progress of our project starting from problem statement, concept generation, concept evaluation and consequently arrived at a prototype design which was modeled in 3D using CAD software. We finalized the material selection for each component of the welding simulator as well as the dimensions required for each component. Plus, the stress analysis done on the sensor box shows positive results. Additionally, all design parameters outlined were adhered to. The next phase is to proceed with the manufacturing stage of the prototype with possible design changes if the situation demand it. A Gantt chart is attached in the appendix section to show the rest of the milestones to be achieved.

We consulted Prof. Frank Ferrier regarding this project and as a result of our interactions with him we realized that there is room for improvement in tracking the movement of the welder. Our current issue is that there are a lot of error in measuring the distance between the emitter and the sensor in the welding gun. To improve this, we can introduce a pickup on the opposite (away from sensor) side of the box to minimize the error. Other than that, instead of using Sixense technology, we can build our own magnetic field emitter, imitating similar working principles as the Sixense Hydra’s current model. The conduit attachment to the welder gun in current design imposes yet another challenge for the design. The conduit restrains the movement of the user while in its simulation mode where the user will not be able to rotate the welding gun freely while welding. Improvements can be made to overcome of this problem by installing Wi-Fi or Bluetooth to activate the trigger on the welding gun. However, the cost to implement this will be high and we are constrained by our budget limit.

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Bibliography/References [1] Lewotsky, Kristin. "Welding Simulator Slashes Training Costs and Materials." Design World Online. Design World, 03 Nov. 2011. Web. 19 Oct. 2014. [2] Fast, K., et al. (2004). Virtual training for welding. ISMAR 2004: Proceedings of the Third IEEE and ACM International Symposium on Mixed and Augmented Reality, November 2, 2004 - November 5, 2004, Arlington, VA, United states, IEEE Computer Society. [3] Anon, 2006. Types of Welding. Available from: http://www.ajeepthing.com/welding.html [4] Anon, The History of Welding. Welding - Information And Training Guides About Different Types Of Welding. Available from: http://gowelding.org/history_of_welding.html [5] Claude Choquet, 2008. ARC+®: Today’s Virtual Reality Solution for Welders [6] Anon, 2014. What is Welding?. Wise GEEK: Clear Answers For Common Questions. Available from: http://www.wisegeek.com/what-is-welding.htm [7] Anon, 2014. Mig, GMAW, Wire Welding, MAG. Weld Guru. Available from: http://www.weldguru.com/mig.html Website Links Figure 3: http://weshop.ph/s/Tweco.html Figure 4: http://store.cyberweld.com/mituhe60de6i2.html?utm_medium=shoppingengine&utm_source =googlebase&cvsfa=2530&cvsfe=2&cvsfhu=6d697475686536306465366932&gclid=CJTW5cr8pcICFVGCMgodPG8AdA

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Appendix Quality Function Deployment

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Table 7: House of Quality

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Gantt Chart Table 8: Gantt Chart

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Concept Generation Sketches

Figure 15: Sensor Housing Concept 1

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Figure 16: Sensor Housing Concept 2

Figure 17: Welding Gun Concept 1

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Figure 18: Welding Gun Concept 2

Figure 19: Welding Gun Concept 3

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Pugh Matrix

Table 9: Pugh Matrix

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Final Design Sketches

Figure 20: Final Sensor Box Concept

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Figure 21: Final Welding Gun Concept