Welding Station
Michael CorreiaZach Lamar
Ryan Fisher
Matt Leigh
Table of Contents
1.1 – Background of need 4
1.2 – Customer Needs 4
1.3 – Literature review 4
1.3.1 – Prior Work 4
1.3.2 - Patents 4
1.3.3 – Codes and Standards 5
2. Problem Definition 5
2.1 – Customer requirements 5
2.5 – Test and Evaluation plan 7
3. Concept Development 7
3.1. Overview 7
3.1.1. Creative Strategies 7
3.1.2. Governing Principles 7
3.2. Synthesis and Analysis of Overall Concept 7
3.2.1. Station Configurations 7
3.2.1a. Industrial Hood 8
3.2.1b. Downdraft Table 8
3.2.1c. Pipe with “Arms” 9
3.2.2. Fan and Filter Configurations 10
3.2.2a. Standalone 10
3.2.2b. Dust Collector 10
3.2.3a. Table design 11
3.3. Evaluation 11
3.4. Refinements 12
3.5. Selection 13
4. Design Specifications 13
4.1. Design Overview 13
4.1.1. Description 13
4.1.2. Design Schematics 13
4.3. Physical Specifications 16
4.4. Product QFD 17
4.5. Subsystems 17
4.6 Design Deliverables 18
5. Project Plan 19
5.1. Research 19
5.2. Critical Function Prototypes 19
5.3. Design 19
5.4. Construction 19
5.5. Testing 20
5.6. Project Deliverables 20
5.7 Schedule 20
5.8 Budget 21
5.9 Personnel 22
6. References: 22
7. Appendices 22
7.1. Loss Calculations 22
7.2. Team Member Resumes 23
7.4. Component Specification Sheets 28
1.1 – Background of need
The University of San Diego’s engineering department currently has a welding area that is insufficient to the needs of the students. It only allows one student to work at a time, has minimal storage, and does not have an adequate fume extractor. The customers requiring an improved welding station include: the University of San Diego, USD Engineering Faculty and staff, USD Environmental Health and Safety, the San Diego Fire Marshall, and current and future USD student engineers. All of these people will be either end-users of the new welding station or validating that it works safely. The current welding station is inadequate and needs to be redesigned. The University of San Diego is the most direct customer, as the welding station is built for the school to keep. The USD Engineering Faculty and staff will be using the welding station to teach students how to weld as well as using it for their own projects. USD Environmental Health and Safety as well as the San Diego Fire Marshall need to make sure that the welding station is safe for use and will not start fires. Current and future USD Student Engineers will be using the station to learn to weld, practice welding and building their own senior design projects with it.
1.2 – Customer Needs
The Mechanical engineering program at the University of San Diego has an increasing need for a well functioning welding table and clean air in the engineering workshop. A good welding table is strong enough to support sufficient weight, rigid and sturdy so that it will not shake if slightly bumped. It is also durable enough to withstand the abuse of welding and efficient in regards to balancing storage space availability and space consumed in the basement. The next need is clean air; currently only one person can weld at a time using the current fume extractor. Also the fume extractor needs to be positioned close to be effective. A new fume extractor setup would allow for two simultaneous welders work and provide cleaner air in the workshop. With the addition of a new, redesigned welding station, each student will have more time to practice welding and their welding experience will be greatly enhanced.
1.3 – Literature review
1.3.1 – Prior Work
A welding table typically has a sturdy structure with an aluminum table top as the surface. A good welding area has plenty of storage so there is no clutter for the welder, as well as organization so the welder can work efficiently. Some type of a fume extractor is always used; most commonly an overhead extractor is used with a flexible arm so the welder has the freedom to move it where he/she feels would be best. When the welding is being done outside, no fume extractor is needed due to the openness of the welding site.
1.3.2 - Patents
Patent number 5511764 describes a self contained welding station with the fume extractor located beneath the table itself. This downdraft fume extraction setup is not ideal for the Loma workshop because it has a few shortcomings. The first one is that with a downdraft table, the fume extractor becomes less efficient as the sheet metal gets bigger, because then the vacuum is blocked and fumes will rise. This setup is only helpful for small welding jobs. The design is also not very space-efficient; there is minimal storage space available underneath the table.
Patent number 3886344 describes a fume extractor that is attached directly to the nozzle of the welding torch. This makes the torch heavier and more bulky to manage. This is a good idea for experienced welders that know how to handle a welding torch, but not as good for beginners that are still learning.
1.3.3 – Codes and Standards
Welding is a very dangerous activity in that it creates harmful fumes as well as extreme temperatures on metals. There are many codes and standards that apply to welding in general. The Occupational Safety and Health Administration (OSHA) has many standards that will be followed for a safe working welding environment. The standards that will be followed are:
· Nothing flammable will be used in the construction of the area
· All of the air will be filtered as to remove the harmful fumes
· proper safety equipment will be provided
All of the codes for fire safety set by the National Fire Protection Association will be followed because of the possibility of a fire due to the hot sparks created while welding.
One fire code in particular that may cause a substantial problem in the design process is NFPA Code 8.2.2.1.2. This code states that no operation that generates sparks can be attached to a dust collector.
2. Problem Definition
A redesigned welding workstation is needed in Loma 6 for more efficient welding and other related actions. The workstation needs to be ergonomically friendly and space efficient, able to withstand wear and tear form welding related actions, and easy to maintain. For safe welding, an improved fume extractor is needed for the removal of toxic waste/air.
2.1 – Customer requirements
Here are the customer requirements that will need to be followed in order to deliver a product the customer will be happy with:
2.1.1 – Form
The welding station is expected to have the following attributes:
- Appearance aesthetically pleasing and similar to standard welding workstations
- Table surface of aluminum
- Table flat to within 0.010 in. over 6 ft.
2.1.2 – Fit
Due to limited space in Loma 6 these requirements must be met:
- Overall height ergonomically designed for comfortable usability
- Storage capacity for all welding workstation accessories
- Workspace provides room for one, average sized user
- Space within Loma 6 utilized efficiently
- Machinery in Loma 6 will not interfere with station
2.1.3 – Function
The following are required functions of the welding station:
- Weld various metals together in a safe and efficient environment
- Achieve noise level less than 75dB operating at 100% flow
- Functional for 25+ years
- Maintenance costs less than $1000 over 10 years
- Easily serviceable and workstation components easily replaced
2.2 – Assumptions
The assumptions that will be taken into account will be:
- Customer Requirements will not be significantly altered midstream
- Loma 6 will be easily accessible
- Welding Workstation will be used safely and appropriately
- Welding Workstation will be used by students, faculty, or staff, trained in safe use
2.3 – Constraints
The constraints that will have to be met for the welding station are:
- Must be completed within 9 months
- Complexity must be within the capabilities of the design team
- Must meet all applicable codes, standards, and government regulations
- Must be stable
- Must be easily serviceable
- HVAC/Fume Extractor must operate at a minimum of 1200cfm for increased ventilation
2.4 – Customer Requirement Schematic (Figure 1)
Figure 1: CR Schematic
2.5 – Test and Evaluation plan
When the project is complete, testing will be performed on the area and the equipment to make sure everything is in working order. The most important test will be an air quality test which will be performed by welding in the area with the extraction running and then taking air samples and having them tested for harmful fumes. If the tests come back negative, then we will know that the fume extractor is working up to the desired standards.
The table will be tested for its strength and durability by adding a specific amount of weight to the top of the table to make sure it can withstand that load. We will be testing the table with roughly four hundred pounds. This goes with the assumption that nothing over four hundred pounds will be placed on the table.
3. Concept Development
3.1. Overview
3.1.1. Creative Strategies
Research and analysis on industrial welding stations played a large role in the development of new concepts. The ideas were advanced through the processes of brainstorming, sketching, visualization, and role playing.
3.1.2. Governing Principles
Key principles that govern the welding station are:
· Statics
· Mechanics of Materials (material strengths, structure design, component stresses)
· Ergonomics
· Heat Transfer (heat due to welding, exhaust gases)
· Fluid Dynamics (air flow, ducting)
· Acoustics (noise control)
· Electronics (control panel)
3.2. Synthesis and Analysis of Overall Concept
Each of these ideas came from concepts already in use in industry. These designs each have their fine points, especially since many are open to customization and modification for future upgrades. Ultimately, the ideal concept will be one that requires the least amount of construction, is the least expensive, and provides the greatest ease of use and benefits.
3.2.1. Station Configurations
There are three main ideas for the way in which the welding station could be configured. These are: an industrial hood, a downdraft table, and a pipe with one or multiple “arms”. In addition to these air entry configurations, there are a couple of different ways that the fan and filter system can be configured as well. One idea is to build a standalone fan and filter unit. The other idea is to modify the dust collection system that already exists in Loma 7 and extend the ducting to the welding station in Loma 6. Both of these ideas is suitable for proper fume extraction and can be connected to any of the station configurations.
3.2.1a. Industrial Hood
Industrial hoods are most often found in kitchen stove units as heat and fume extractors. A similar design would be incorporated into the welding station with the hood acting as a fume extractor (Figure 2). The hood would be constructed of sheet metal, attached to the wall above the table, and provide a vacuum over the entire surface of the table. This design will only work with the hood positioned at the correct distance from the table surface to provide adequate vacuum in pulling the fumes from the source and into the filtering unit located above the hood. One advantage to this design is a greater quantity of air moved away from the table which improves fume extraction. Another advantage is the extra storage space available around the table. Additionally, this design allows for the easy installation of a spark arrestor and sound damping material. Also, sparks are unlikely to be pulled from the table through the hood.
Figure 2: Fume Hood
3.2.1b. Downdraft Table
Downdraft extraction is a concept discovered through research of current welding stations. The downdraft concept consists of a fume extractor built into the underside of the welding table (Figure 3). The table top has evenly spaced holes over the entire surface which are large enough to provide sufficient airflow, but small enough to prevent work items from falling through. The fume extractor creates a vacuum through the surface of the table, and then pulls the fumes through a filtering unit mounted under the table. One advantage to this design is that the table and extractor can be built as one unit. On the other hand, it would limit storage space for equipment and materials. With this design, there are noise concerns as the fume extractors are very loud and this is all one contained unit. This design is also more suitable for a factory setting than for a small workshop.
Figure 3: Downdraft Table
3.2.1c. Pipe with “Arms”
Lincoln Electric installs custom fume extraction solutions. An illustration in their catalog shows a single duct with multiple flexible hoses (arms) extending to individual welding stations (Figure 4). The arms are adjustable such that the welder could move them into the desired position to concentrate vacuum where it is needed. A similar design would be incorporated into the welding workstation. One advantage to this design is that the user could turn off one arm when not in use by means of a blast gate built into the ducting. This setup is also very space efficient leaving the over head space virtually open for storage. Negatives to this design are that it is more difficult to install a spark arrestor and due to the number of bends in the pipe, airflow will be decreased.
Figure 4: Pipe with Arms
3.2.2. Fan and Filter Configurations
3.2.2a. Standalone
Any of the air entry configurations could be connected to a standalone fume extraction unit. This unit would include a fan and a filter to provide sufficient suction and pull the toxic fumes away from the workstation filtering them into breathable air. One downfall of this idea is that it would be more expensive than the alternative. It would also take away from the already limited space in Loma 6 and 7. On the other hand, building a standalone unit would provide an easier way to obtain the required air flow and eliminate the hazard of sparks mixing with wood dust from the wood shop. To reduce excess noise from this system the fan and filter would be encased in an insulated box.