Removable windshield scraper blade

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Revision as of 16:28, 8 December 2007

Final Report DUE DEC 7th* - ONE PER TEAM

• Will be accepted up to Dec 11th < midnight

SUBMIT AS WORD, PDF, OR WIKI PAGE

In your final report, you are looking to 1) provide evidence and make a case to support the need for your new design; 2) provide documentation necessary to fully describe and define the detailed design for production; and 3) use engineering analysis and your prototype to demonstrate feasibility of the design. Each team should document any information needed to accomplish the above objectives. To help you avoid forgetting anything major, a minimum requirements checklist will include:

Executive Summary

(1-page max)

- Appropriate background on the project.

Market Research

- A clear statement of the opportunity you have identified, and documentation of market research to support the need.

The need that we found was for people to have a way to get ice off there windshield with out having to be outside scrapping it. We found that there where no other products designed around this purpose. This is what we saw as our opportunity to fill a niche that was clearly not being meet. We felt that if an effective deign could be made people would buy the product because of the near universal distance for standing out side in the cold while scrapping ice off your windshield.

When trying to decided if the windshield scrapper idea that we came up with would be something that people would actually want to buy we decided to sample the people we knew to get there reaction to design idea. We each contacted 5-10 and between the four of us only one person didn’t like the idea. There were however several people that had reservation mostly having to do with how easy it would be to attach and how quickly it would get ride of the ice.

When we were trying to decided on what kind of attachment we should make between the wipers and our blade we thought it would be time to do some more market research on what most people’s windshield wiper blades look like. What the problem boiled down to was did a great enough percentage of people’s wiper blades have holes on top and a recess that we could justify the use of a permanent attachment part that utilized these holes. To get a good cross section of what our target demographic (having plenty of disposable income and like gadgets) had on there car we started out in CMU’s parking lot and surveyed the cars, it also couldn’t hurt that CMU is ranked very high for out of shape campuses. We found rather favorable results most cars windshield wipers had holes in there wipers. Then we decided to expand our sample to include cars parked in the Pitt university area and found similar results. In the end we sampled more then a hundred cars and found when all was tallied up the result was 1 to 13 in favor of holes.

Design

- Engineering drawings that fully specify the production design and its function, including a bill of materials listing each component, dimensioned drawings of each custom part / catalog references for each purchased part, specification of materials and manufacturing processes for each part, and documentation of how the components are assembled.

ABS is a thermoplastic and lends its self to processes such as injection molding very well, a quick round up of its properties is at the end of this section.

Lustran ABS 433 comes in black high gloss which should give our design a nice slick look and is one of the low costing forms of ABS. It is also commonly used in injection molding application. ABS 433 is used for automotive applications and other consumer applications. The supply of that we would use is LanXess, there is a PDF in the reference section that has the technical data for using this plastic in injection molding. It is also important to note the environmental impact of Lustran ABS 433 which meets all enviormental guidelines for both the US and the EU. LanXess offers documentation to show that it meets the several guidelines such as the RoHS-Directive.

Our initial run will probably be smaller until we have design fully perfected because of this we will probably start out with a cheaper aluminum mold. This will cost much less then a steel mold and we will be able to make them quickly with a CNC in this way we can go though a few generations before a steel mold is constructed. The most complex part is the chassis and it is not all that complex so the molds and process should be very low cost. Assuming that we have a total first run of 500,000 and factoring that our aluminum molds will have to replaced a couple of times in the process the costs per part are in the table below these numbers are based on cost estimator software provided by David O. Kazmer, P.E., Ph.D. from University of Massachusetts Lowell.

Which gives a total cost for the ABS parts of: $1.51

The number of cavities for our mold is in the table as well because it as a great impact on the cost of the process. This is because it is much more economical to have more cavities on medium and small parts, like what we have. Some of the parts did not seem as though they could have the extra cavities but the chassis has places for at least four and the knob for at least two.


Properties
Tensile Strength
5000-7500 psi
Flexural Modulus
270,000-380,000 psi
Impact Strength
3.0-7.5 ft-lb/in notched izod
Maximum Temp.
200 F short duration, 140 F long term

Analysis

- Engineering analysis of the design including 1) an appropriate numerical analysis for your design (required for all) 2) a DFX/FMEA analysis as appropriate for your design, and 3) documentation of any engineering testing performed to support design decisions. In all cases, clearly state assumptions and conclusions.

After the first snowfall of the season, we were able to test our prototype on an actual windshield. The before and after pictures shown above shows that the Plexiglas blade does not scratch the windshield when a large amount of force is applied, and clears away the snow and ice in one back and forth motion. This affirmation told us that Plexiglas is a safe choice for the blade and that our final design would be safe to mount on a windshield wiper and run with the wiper motor.

Video of windshield wiper attempting to clear snow/ice

Video of OUR windshield wiper blade clearing snow/ice off of same car

QFD

- A QFD to show (at minimum) the quantifiable engineering targets you have set for the design, relationships between engineering specs and stakeholder needs, and benchmarking of competing products. As always, explain your conclusions, such as what strengths your design has over competitor products and who is likely to buy it.

Final Prototype

- Documentation of the final prototype including a discussion of what it demonstrates, what was learned from it, and how it differs from the final design.

Testing of Final Prototype

- Documentation of user-testing and user-feedback on your design and prototype.

Should the design be pursued for production?

- A conclusion of whether or not your design should be pursued for production and why.

Next Steps

- Identification of next steps and any remaining barriers to bringing the proposed design into production.

Team Contributions

- A section on design process and team dynamics that briefly describes the design process path followed by the team and lists semester contributions and team roles from each team member.

Some teams may include additional information, such as a provisional patent draft, optimization results, functional decomposition, VOA, survey results, product family analysis, detailed cost estimation, etc. Each team should identify which aspects are appropriate for making the case for their own product and aim to impress the client with thorough and appropriate work necessary for the client to make a decisions on whether or not to pursue your product further.