ALAN LI

 

 

Objective: To develop a mechanical pencil that is capable of using different lead sizes while maintaining the ease of use and affordability of current mechanical pencils.

 

Refined Criteria and Constraints:

• Must be compatible with at least two different common lead sizes(metric: number of lead sizes compatible with the pencil)

• Must not exceed 11.0 grams in mass(metric: mass in grams)

• Must be between 7mm and 15mm in diameter(metric: the greatest diameter of the body of pencil in millimeter)

• Must be intuitive to use with less than 5 guidelines (metric: number of guidelines)

• Must not exceed 10.00 in cost (metric: retail price in Canadian dollars)

• Must be between 130mm and 150mm in length (metric: length of the body of the pencil)

 

 

Iterative Design Process:

 

The design process in the conceptual design brief involved the refinement and clarification of the design brief itself, the generation of several sets of solutions, before and after the refinements, and using multiple iterations of a Pugh chart to aid in selecting a solution.

 

Refinement of Original Brief:

The design brief which we recieved clearly identified the problem of mechanical pencils accepting only one lead size, but required clarification on the main stakeholders and several contraints:

 

Stakeholders:

In the original brief, the main stakeholder was said to be students who run out of lead of the correct size. However, we found that it would be unlikely for a student to own a lead size for which they did not own a compatible pencil. To clarify the main objective, we added drafters and artists as new stakeholders, who often need to use different lead sizes for different purposes. This resulted in an added requirement that the solution must not change the lead size that is inserted.

 

Constraints:

We found that the original brief emphasized usability in its main objective, but did not list specific constraints for usability. To better determine what kind of solution was needed, we added several usability criteria and constraints, such as the time it would take to activate the lead advancing mechanism.

 

Generation of solutions:

In order to generate divergent solutions, we formulated a morphological chart of the functional decomposition of a mechanical pencil, and various methods of meeting the functions. We came up with solutions ranging from lead rollers to grinders, which would convert any size of lead into a powder before depositing  it onto the page. However, the addition of a new stakeholder and requirements required the re-generation of solutions, as several of our previous solutions converted different lead sizes into a single effective size.

 

 

 

 

 

Assesment and Selection of solutions:

Using a Pugh chart, we compared the relative performance of each candidate solution. In our first iteration, we used a standard Bic Matic mechanical pencil as a reference. However, this was not very effective, as the Bic Matic did not accept different lead sizes. This meant that we could not compare the main requirements for a solution, such as the range of lead sizes accepted or how quickly it could change between lead sizes, as it was not applicable to to the Bic Matic. For the second iteration of the Pugh chart, we chose the multi-barreled pencil as the reference design, as it was the closest to existing products.

We ultimately selected the modification design as our solution because it builds upon the proven design current mechanical pencils, meaning that there are fewer variables which could result in its failure. 

For details on the selected design, see the Kickstarter Package