Table of Contents
Manufacturing system to produce reed valves for accordion restorations by Scott Bellinger.
Team Vision for System-Level Design Phase
- What did your team plan to do during this phase?
The goal of this phase was to develop 50 to 100 options as to how to go through the various different subsections of the manufacturing process. Starting with a high level functional decomposition, we wanted to break down each part and develop various concepts to have a robust set of options for the selection process.
- What did your team actually accomplish during this phase?
After developing the functional decomposition, the entire manufacturing process, from start to finish, was broken down into subsystems. For each subsystem, the group developed plausible solutions, which we then combined together for concept development while simultaneously creating the selection criteria. The concepts are compared to the datum to see the pros and cons of each full system. Additionally, we created a deflection test bench that will be used next phase to test what plastic film most closely mimics the properties of the current reed valves that are being produced in Italy.
The above is a functional decomposition of the system. Starting at the highest level, the function of the system is to be a manufacturing system to produce reed valves for accordion restoration by Scott Bellinger. The second level functions describe the functions that had concepts generated for them. The exception being “interface with user” where the mode of interface and which choices to offer the user where brainstormed. Additionally, the third level functions “move material” and “secure material” appear multiple times and so were deemed important enough to require concepts to be generated for them. The fourth level shows the basics of how the third level functions might be controlled.
Below is the expanded list of Engineering Requirements (ERs). This expanded list has additional requirements driven by the functions in the functionally decomposition (ERs 24-30). It’s worth noting that a few functions do not appear to drive engineering requirements. This is because ER nessicasry for the function was already matched or exceeded by an ER driven by a Customer Requirement (CR) and would have been redundant.
Morphological ChartConcepts Page
Before creating the Morphological chart, our group as a whole brainstormed about 80 plausible subsystem solutions. This is documented in the above link. We used both this list as well as the functional decomposition to build our morph chart. The functional decomposition called out all subsystems in the manufacturing process while the list itself provided the individual actions for each.
The Morphological chart shown above displays our ideation process for each subsystem in the manufacturing process, to the best of our knowledge. Each subsystem was developed from the functional decomposition chart, from there we produced a set of potential solutions that could achieve the goal of each function. Every individual piece was generated with its own selection criteria so we could quantify the strengths and weaknesses of overall concepts.
Concept SelectionLive Document
We combined independent system level products to build a start to finish flow for the manufacturing system. We did this multiple times to create a variety of concepts to compare to one another.This process was done in parallel with developing the morph chart so that we could plan accordingly to develop the pugh chart. It is important to note that after comparing the original concepts to the datum, we then paired what appeared to be the stronger subsystem solutions with weaker ones to offset the potential errors for new concepts. From here we now have to look at the strengths and weaknesses of each selected subsystem and build further to maximize our product
After we developed our morphological chart, we put together a list of 8 concepts, the first of which was our datum in which we were going to compare our other concepts against. We then came up with criteria to rate each concept for different areas of the manufacturing system. A rating of "0" means that the criteria of that concept is neither an improvement nor a detriment to the datum. A score of "-1" means that criteria was a detriment compared to the datum. Similarly, a score of "+1" meant that the criteria was an improvement compared to the datum.
After we went through all of our generated concepts, we tallied up all the "0's", "+1's" and "-1's", we saw that one selection was more feasible than all the others, since it netted a positive score. We can also see which concepts are not feasible based on their very negative net score.
Below is a table showing the criteria, equipment, and values we will be using for benchmarking. As can be seen some of the information is currently unknown due to us not having the proper equipment yet. We are currently working with Balluff sensors in order to find the best option for this application, therefore the deflection height and angle are unknown and precision of the sensor will be known once one is acquired.
Also it is not known how we will be testing our life span for the valves. For this we plan to meet with professors from the System Performance and Reliability Lab located in Slaughter Hall. Specifically for more information on their Highly Accelerated Life Tester (HALT) which can be used for combined stress testing of our valves.
Feasibility: Prototyping, Analysis, Simulation
To begin testing these samples will be cut and valves assembled by hand. Several plastic samples have been received from both TLP and Curbell Plastics. In order to decide which plastic generates the desired deflection profile, the testing bench shown below was built. On the back panel a flow meter and pressure gauge are mounted to help while testing. Currently working with Balluff Sensors to determine which photoelectric distance sensor would be best for this application.
Systems ArchitectureLive Document
The above Transformation Diagram is useful for visualizing how material, information, and energy are intended to move through “the system”, which is represented by the large box in the middle. The inputs are on the left of “the system” and the outputs are on the right. Within “the system” are all of the functions that happen to the input material, information and energy. Additionally, the diagram provides information on how they interact and combine. In our diagram two “subsystems” are specified. The “subsystems” we have specified are essentially, control and “manufacturing process”. Having subsystems in this diagram helps to show which functions are accomplished by what “subsystem”. Having this information gives us a level of understanding of how our system will work that is hard to get from just our functional decomposition or a diagram that lacks subsystems. Later in the design process, having “subsystems” will allow us to determine which function concepts are part of what “subsystem”. It is likely that these subsystems will be broken down to show more detail at a later date.
Additional System Constraints include:
The size of the system must fit atop a table within the customer's workshop.
The system must use standard 120V AC power.
The budget for the system is $1000. Many components and equipment have been provided.
The system must produce a valve within 10 seconds.
Designs and Flowcharts
Below is our timing diagram for the concept that has been selected. Each step of the manufacturing process was given an estimated time and was put in the proper order from start to finish. The total time for the production of one reed valve is estimated at slightly over 10 seconds which is right near the customer required time for production.This timing diagram is tied to all of the engineering and customer requirements since it maps out the entire process from start to finish of one reed valve. This chart takes into account the amount of time it takes for each component to return to its initial condition. For example, the cutting blade needs to extend and retract back to its original position before the indexing dial will rotate. Additionally, there is a small startup time buffer to allow for the components to return to their initial states if they are not already there.
The High Level activity diagram shows how the manufacturing process will work step by step based on user input and selection of the product. After the start of the process the machine will keep producing reed valves until the users desired number of valves is complete. As with the timing diagram, major functions will have their components return to their initial conditions once they have finished their operation prior to indexing.
The functional block diagram shows how each individual part of the design will interact with each other. The Programmable logic controllers I/Os will send signals to each of the individual steps to start and stop certain processes.
Below is our constructed Failure Mode and Effects Analysis (FMEA) for our project. The FMEA has been updated too show new risks that have come into existence as we move forward in the design process. Risks with higher importance have corrective actions in place to minimize the severity and possible remove the risk completely. Some of the risks identified so far are tied to certain engineering and customer requirements and this is expressed in the FMEA. Risks that do not have any ERs or CRs effect the process as a whole. This could mean effecting whether the project is completed on time or the overall quality of the reed valves.
Using the importance numbers from the FMEA the total risk for our project is tracked over time. With it still being early in the design process no risks from the previous cycle have been removed yet. A few new risks have been added to the FMEA, causing the importance number to increase slightly. Moving forward, old risks will be looked at and removed if they are not seen as a hazard to the design process. This should cause the the importance number to start slowly dropping over time.