Team Vision for System-Level Design PhaseOur vision for this phase was to demonstrate critical system level structure. Our critical system level areas were identified as:
- Hold wire
- Control Wire
- Tension Wire
- Maintain Safety
- Move Wire
Task List for Systems Design Phase
Engineering Requirements Mapping
Changes from phase I engineering requirements and phase II engineering requirements. Green represents engineering requirements that stayed the same, yellow represents newly added engineering requirements, and red represents engineering requirements that were not used for the mapping process.
- Research was conducted looking into OSHA Requirements and general safety practices to educate team members on the current industry standards and regulations as we continue forward with design and prototyping for future phases. To see this research, please see the following document: Safety Research
Morphological Chart and Concept Selection
Based on the Morphological Chart above, the team was able to produce multiple concept designs with various design goals for each concept. Click on the following links to see the various iterations produced from our Morphological Chart.
- Feasible Concept
- Cost Effective Concept
- Best Case Concept
- User Friendly Concept
- Cost Effective & Feasible Concept
System-Level Selection Criteria:
Ability to maintain and control tension:
- How well is tension controlled?
- What is the response time?
- Can a proper tension be applied?
- Can different tensions be applied?
- How easy is it to adjust tension?
- Is tension control automated or manual?
Ability to maintain and control speed:
- How well is speed controlled?
- What is the response time?
- Can speed be altered/adjusted?
- Is speed control automated or manual?
Lower cost to run:
- How much does it cost the operator/company to run the fixture?
- How much power is drawn during use?
- What is the cost/availability of replacement parts?
- Will the components wear?
- What is the operator’s time to set up?
- How much downtime will the system require?
Lower manufacturing cost:
- What is the price of the components?
- What is the cost of the manufacturing process?
- How long will take to build/assemble the system originally?
Safe for wire break:
- What is the response time to a wire break (shut down)?
- How safe is the operator if a wire break occurs?
- How safe are the machine components if a wire break occurs?
Safe for high heat:
- What is the response time to a system overheat (shut down)?
- How safe is the operator if overheating occurs?
- How safe are the machine components if overheating occurs?
Ease of integrating with other subsystems:
- Can components “talk” with controller?
- Do components support each other mechanically?
- Do all components fit in reasonable 3D space?
Efficient power consumption:
- How efficient is each component?
- How efficient is the system as a whole?
- Do components add inertia to overcome?
- How badly do the components wear?
- How often is component replacement needed?
- How accurate are the sensor readings (temp, tension, etc.)?
- Does every component have 100% functionality in both directions?
Feasible for one year:
- Can the 7 students of P16602 successfully design, test and build this concept in one year?
Ease of use:
- How much time does it take to setup?
- How many operators does it take to set up?
- Are the controls simple and straightforward for the operator to use?
First Pugh Iteration
Second Pugh Iteration
Take-Away from Pugh Analysis
- Meyer Burger machine wire movement is driven by rollers, what impact will changing to spool driven wire have?
- Spooling techniques may be the limiting factor for
the ability to handle multi-directional wire movement
- Must ensure spooling mechanism will not break/catch the wire will running in reverse
- A microcontroller could possibly work, but would require overly lengthy development work
- Infrared sensors in the best case system concept may
cause troubles with space and layout during integration
due to line of sight issues
- Original “best case” performed well in the Pugh Analysis, but had room for improvement
- Better to have easily replaceable/cheap inserts on
components that will wear (pulleys) than expensive metal
pulleys that would need to be completely replaced
- Pugh came to the same conclusion as Meyer Burger to use pulleys with plastic inserts
- The cost effective system concept only considered manufacturing cost not run cost
- Second iteration showed that the feasible system concept was not a good option as original assumed
- Using the Meyer Burger machine as the first datum led to new questions and things to learn about the Meyer Burger DS 264
- 3D location of components should also be investigated
- It is very important to reduce ambiguity when completing team exercises
System Level Concepts
Feasible Design Sketch
User Friendly Design Sketch
Feasibility: Prototyping, Analysis, SimulationDuring the Systems Level Design Phase, our team set out to analyze the feasibility of our project through some technical analysis. The following questions were proposed and answered through simple methods of benchmarking and analysis and solving via simple tools:
- How much electrical power will our system consume?
- What is the force on each pulley at 24 N (slurry) and 45 N (diamond)?
- How long can the wire last doing a lower volume of cuts? (How frequently we need to index wire for low volume)?
- How much power will our fixture consume?
- How would the work piece being pushed onto the wire affects its tension?
- How much torque is needed to spin a spool that holds 475 km of wire while maintaining tension at 25 N?
- What motor (size/type) will we need to choose to handle all of the fixtures’ components?
For full solutions of these questions please see the following document: Feasibility Analysis
Top Ten Risks at this Phase
Included below is a link to the full list detailing the teams risk assessment for reference.
Plans for next phase
- Spool subsystem - Hannah
- Frame subsystem - Caleb
- Mechanics of Tension subsystem - Sarah
- Control Subsystem - Joe
- Safety Subsystem - JD
- Simulation - Fares
Key Related Technical Questions to Include:
- What motor selection to pair with spools? What orientation to put spools in relation to each other? What is the best way to spool the wire?
- What is the general layout of all components? How will components be mounted in 3D space? How to determine wire path?
- How will tension be monitored? Where will tension monitoring system be located within fixture?
- What is sequence of our fixture? How do sensors/motors communicate with controls? Faults?
- How will the enclosure protect the user? How will safety sensors tie into overall machine controls? What is the method to detect wire breaks? Is it safe?
- How will the workpiece effect the tension of the wire? How to simulate guiderollers? How will team account for unpredicted results? Will it work?
Additional Plans for Next Phase:
- Keep risk table and engineering requirements up to date
- Create the subsystem functional decomposition
- Revise test plan to make sure all requirements are met
- Preliminary Test Plan
- Continue research to answer key technical questions
- Update action items from System Design Review
15 Week Plan:
Customer VisitCustomer Visit Questions Answered
Design Review Q&AWhat was the point of benchmarking?
To guide with concept selection with quantitative comparison by comparing to the existing DS264 wire saw.
What is unsafe about a wire break?
Safety of user, components and workpiece.
Do you plan on evaluating on higher
Yes, especially if we consider switching to diamond wire.
What is "Joe"? (Pugh Chart)
Overview of Joe's hand sketched system level design.
How do you change the tension?
Via tensioning arm/dancer pulley. Discussion occurs leading to the conclusion that spools must be involved in controlling the tension. What if the spools are running at different velocities? What about initial startup tensioning?
Where is the power used?
To overcome inertia during acceleration, friction during steady state.
Does your subsystem set the tension for the whole
We believe so. It is the tensioning and spooling system, after all.
Master PLC for all groups?
Yes, set up by Joe.
How will Sarah handle team issues?
Bring up issues and talk as a group. Comfortable in her role.
What is the primary concern for scope
Ease of use.
Action Items for Subsystems Design Phase
- Ask Professor Wellin for his assistance with feasibility analysis.
- Look into how the guide rollers and workpiece will affect tension.