Downselection

Stage 1: Initial

Our initial stage of downselection involved downselecting separate components, that is the tips of the instrument, the form factor, and the dispersion mechanism. This allowed us to objectively evaluate every component of the product in isolation and look at the best solution for each function our product serves. The results from our stage 1 downselection allowed us to create better "top concepts" for stage 2 of our downselection. We chose to use a selection matrix for stage 1 as it helped us weigh/rank the tip and dispersion mechanisms against each other so as individual we could make informed decisions about how we wanted to proceed with our final concepts.

Link to Spreadsheet

Down Selection Stage 1

Stage 2: Final

For our final phase of downselection, each team member came up with the solution they thought was best (see Top concepts), and we compared our ideas to each of the requirements we had found from the QFD through a concept scoring matrix. The criteria that we evaluated the concepts against were pulled directly from our QFD and using our ranking system in the QFD we made a similar ranking for the criteria in our matrix. We ranked each criteria from 1-15 with 1 being the least important and 15 being the most important. Here, more complete ideas were compared and we decided to go with a combination of the Ball Bearing Flat Brush and the Roller Ball Bottle Brush concepts since it was the most well-rounded idea of the lot and ticked the right boxes for a great user experience. It is important to note that Cavity Hair Brush and Ball Bearing Flat Brush ideas both scored the highest, and Roller Ball Bottle Brush came in a close second. We will discuss below in greater detail the arguments for and against our highest scoring ideas and HERE we will discuss our final proposed concept.

Link for the spreadsheet.

Down Selection Stage 2

Concept Arguments

Refer to our Top Concepts Page for reference images of the potential concepts developed by each team member.

Ball Bearing Flat Brush: Score (408)

Advantages:

The advantages to this concept are that because of the bigger ball bearing tip design, messiness is reduced. The ball bearings and direct grip of the palm to the handle also create a system where the flow is much more controlled. This design is compact which makes it easy to carry and simple for the user to use.

Disadvantages:

There are 2 main disadvantages to this design. The first is that because of the overall shape of the deivce, the oil/serum resevoir size is signifcantly reduce and doesn't allow enough for a full applicaton's worth of product volume to fit in the device. The second disadvantage is that the roller balls are too close to the base of the design and make accessing the scalp more difficult. The added much larger size of the ball bearings doesn't make this any easier.

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Vibrating Hairbrush: Score (363)

Advantages:

This concept's biggest advantage is the feel good factor. The incorporation of the vibrations and the battery powered plunger system to disperse the product is also a plus that creates a very fancy experience for the users. The hair brush style grip also makes it easy for users to maneuver the device because they don't need to exert as much force.

Disadvantages:

This concept has many disadvantages that outweight the advantages. Though the vibrations create a feel good experience on the user's scalp, the current deisgn would make the entire device vibrate which then creates a counter discomfort on the hand or palm of the user. The force required to hold the handle would increase the intensity of these vibrations as well. Similar to the cavity hairbrush design, the brush style grip limits the ability to fully cover the scalp. This design also incorporates one time use cartridges of oil or serum that creates unecessary additional waste and makes the device overall more difficult to use. The final disadvantage of this design is that the incorporation of electrical components, while helpful for dispersion of the product, makes cleaning and the potential contamination of the electronics a big hassle and concern.

Roller Ball Bottle Brush: Score (403)

Advantages:

The biggest advantage to this design are that the sleek small and longer bristles allow the best acess to the scalp and therefore make scalp coverage the best for this design. The larger more spherical design also allows for a larger reservoir for oil/serums and creates a large surface area for users to grip.

Disadvantages:

A big disadvantage to this design is that using tips as small as ball point pens creates an uncomfortable experience for the user. In this design, users are also required to squeeze the device in order to help the product be dispersed and this extra action not only increases the pressure on the scalp but it makes the whole oil/serum application process with this device more tiresome and less "easy".

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Cavity Hairbrush: Score (408)

Advantages:

This concept had a few clear advantages. By using a hair brush style grip, it makes the device overall easier to use for the user as they don't need to exert as much force to maneuver the device. Another advantage of this concept is that access to the scalp is fairly easy. Because the bristles are designed to be long and thin, they can push through hair and access the scalp much easier than a larger bristle would be able to.

Disadvantages:

The main disadvantage with this concept was that our goal was to spread the product around the scalp and when you use a hairbrush design, the product automatically gets spread onto the ends of the hair and based on our definition of messiness, increases potential for it. Another disadvantage of this concept is that the oil/serum is only being dispersed through a minimized number of bristles so the complete scalp coverage would be more difficult to achieve.

Feasibility Estimation

We estimated what the weight of our brush needs to be so that it is comfortable to hold for the user. We needed to take into consideration the liquid in the reservoir. Using the density of oil, for a particular volume, we calculated what the weight would be. Around 75 ml volume is feasible. This would mean that our device (without liquid) could weigh 32.5 g. We would choose appropriate materials for manufacturing based on the calculated weight.

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