PROJECT CONCLUSION

In conclusion to this project we would like to say that this was a fun, challenging, and educating design. We learned alot from the difficulties we encountered and are able to see that the most important part of design is the details. The accuracy must be there before you take the next step, otherwise, you will encounter problems during the assembly phase. The advice we would give to others would be just that, do one step at a time and make sure that step is accurate before you move on. After taking the Engineering courses at Itt-tech, all three of us are leaning towards Mechanical Engineering.

THE MODIFICATION

Group Design brainstormed several ideas about the modification of this assembly and decided to do something that would enhance the practicality of this machine. We chose to modify the arm from a bench mount to a wall mount. This would allow the fixture to be secured to a wall or welded beam support saving the space of a weld bench. This is practical for consistant production in small work spaces and would create a smaller workstation giving the worker greater accessibility. The modication was a simple adjustment and was quick and easy.

THE ASSEMBLY OF THE WELDER ARM

The initial assembly was the most challenging part of the design process. We encountered some holes that were not placed properly and had to modify some part drawings. It was also a challenge to contrain some parts, such as the supports and brace. Group Design worked as a team taking turns constraining and discussing ideas before we implemented them.

THONG

The thong is the connection to the holder that is the link between the body of the fixture and the work tools. They conduct electricity and play a role in the cooling process. They also apply the force needed to created the weld nugget. The tips are made of copper and can be changed out when they get wore down. The design of this part was relatively simple. The commands used most were revolve, extusion, and various other sketch tools.

HOLDER

The holder is the part of the welder arm that "holds" this whole assemly together. This part is either directly of indirectly connected to every other part on this machine. It was also by far the hardest part to draw and required a lot of teamwork and problem solving. We encountered errors during the design process because we had several missing dimensions. This is where the problem solving came into play. We had to deduct from various other dimensions, the proper lengths and angles required to complete this part.

SUPPORTS

The supports are welded to opposite sides of the midpiece and connect to the holder with a 3/16 slotted spring pin. They provide stability and support for the connection of the arm to the handle. While drawing the supports the use of angles and lines were used most. While drawing this part Sylena had to make sure to have everything constrained properly to make sure all size specifications were correct. Otherwise, there would have been a problem during the assembly.

FIXTURE

The fixture is the part of the welder arm that is attached to the midpiece which is welded to the arm and supports. It is secured by three hex head machine screws.This part was relatively easy to draw using mostly circles and extrusions. The most difficult part of drawing the fixture was the proper placement of the holes. With out being properly aligned, we would be unable to properly constrain it in the assembly.

MIDPIECE

This part is the midpiece on the machine. It is designed as the connecting piece in this assembly.
The supports are welded the midpiece and it is functional in the manner that it allows the handle to extend out horizontally. This makes the thongs able to be in the positon to maximize the erginomical concept of the design. This part is made of steel and is secured to the fixture with screws and welded to the arm.

The Arm

This is an isometric and 3D view of the ARM on the spot welder. This part was deigned by drawing profiles and revolving them, the appliancation of angles, extruding, and various other commands.This part is designed to secure the machine to a weld table and is made of steel. With the proper use of the appropriate commands, Matt designed this part with out encountering any major difficulty.

Resistance Welding

The welder arm we are designing is a spot welder. Spot welders use the process of resistance welding to fuse together two pieces of metal. It performs this task by using electrical current, force, calculated amount of time, and a cooling process. This fusing of metal is made possible because metallic objects have electrical and thermal properties.

Mathematically this is expressed by the equation: E = I x R x T
where E = energy, I = current, R = resistance, and T = time. To increase the amount of heat energy you need, you would simply increase the ampacity and time. To decrease the amount of heat energy, you would do the opposite. Resistance welding is accomplished by passing a controlled density of electrical current (I) through the resistance of the metallic workpieces (R) over a specified amount of time (T).

Electrically, metalic objects have a specific level of resistance to the flow of electrical current.This resistance will cause heat energy (electric current) to pass through the work piece. Thermally, they have a melting point, specific heat content, and thermal conductivity. Knowing these properties allows the ability to calculate the amount of heat energy and force needed to create the fuse, as well as time and cooling the fuse needs to create a weld nugget.

The welding current is applied through copper electrodes under controlled force. The diameter of the electrode (the part that makes contact with the workpieces) will determine the density of the electrical current. The force applied when the electrodes make contact, affect the resistance across all interfacing layers including the weld nugget zone and the electrode to work piece interface areas. Force is adjusted to immediately create heat at the interfacing areas. If the force is not applied with the specified amout, excessive heat marks at the electrode-work piece interface can occur which can cause the metal around the fuse to become weak. For this reason, it is very important to have an effective cooling system to take heat away from the surface of the workpieces that make contact with the electrodes in a quick efficient manner.

Welder Arm project objective

Our group chose the welder arm drawing because we thought it would be the best demonstration of the skills we gained throughout our Engineering courses. The purpose of this project is to develop an assembly drawing of the original design, make a modification of it, and present the modified design in multiple formats. The approach we took to begin the design process was to first research the welder arm and have a good understanding of it's purpose, process, and functionality. Then we "brainstormed" ideas about what modification we were going to make, evaluated each idea, and made our final desision. At this point we designated individual tasks and deadlines needed to be met.

Group Introduction

Group Design was created by Tabitha Cooper, Matt Shaughnessy, and Sylena McGowan. We are 5th and 6th quarter students at Itt-Technical Institute and currently taking the Engineering II course. We are working on a group assembly project designing a welder arm with the Inventor 10 program. This project displays basic drawing functions, 3D operations, and the use of constraints.

Tabatha is an intelligent, funny, and a optimistic individual. She is currently working as a reseptionist for 8 Mile Recycling Company. She is a CAD major at Itt-technical Institute and is currently in her 6th quarter. Her long term career goal is to be an Engineer in the mechanical engineering field.
http://docs.google.com/Doc?id=df4776bc_2crj5jsdq

Matt is an enthusiastic, smart, a motivated individual. He is currently working for Silver Lining Tire Recycling Company and is a well rounded and respected worker there. He is also a CAD major at Itt-Technical Institute and is currently seeking internships and co-op programs in the design field. His long term career goal is to be an Engineer in the Aeronautics feild. He plans on continuing his education at the University of Michigan.

http://docs.google.com/Doc?id=df4776bc_0ff7vnnhg

Sylena McGowan is an energetic, intelligent, and motivated individual. She is currently working as a Senior Sales/Account Representative for DYMusic USA. She is a CAD major at Itt-Technical Institute and is in her 5th quarter. Her long term career goal is to become an Engineer specializing in alternative energy. She plans on continuing her education at the University of Michigan.

http://docs.google.com/Doc?id=df4776bc_1cxqxqt2t