The Fight Continues: The Design Process

We are so excited to continue work on our yo-yo! This week we focused on designing all the pieces in SolidWorks so that we can begin work on the molds. Take a look at what we have come up with. 

The bottom piece serves as the base and is made with white injection molded plastic. It contains the nut and shaft assembly (not pictured) that serve as the axle for the string. Nested inside is a clear thermoformed bed to hold the electronic components. These electronic components will cause the red portions of the beaver to illuminate when the yo-yo is spun. The features of the face start with a white injection molded plastic piece which defines the nose, ear shadowing, teeth, and part of the wake. A red injection molded plastic part sits on top with raised extrusions to create the eyes, whiskers, and wake, as well as holes to allow the white features to poke through. The last two pieces are a black injection molded plastic face with holes to compliments all the features below and a white injection molded plastic lid that snap fits onto the base and encapsulates all the other layers. Once assembled, all of the different layers of the design lie flush with each other on the face of the yo-yo.

Design for Manufacturing:

Designing the yo-yo required that we consider several principles of DFM or Design for Manufacturing. Here are a few of the most important ones.

• The majority of the lid has thickness of 0.09 inches, which is thin enough to prevent too much shrinkage and deformity as one would see in too thick of an injection molded part, but is thick enough to support itself and provide a rigid cap on our part.

• Further, in not making the part too thick we prevent excessively long fill times/pressure, as well as reduce cooling time.

• On both the lid and the base,the corner edges of the exterior are filleted to make it more conducive to injection molding

• On the thermoformed electronics bed, the thickness of formed part perpendicular to the yo-yo main face is dimensioned so that central pin mount doubles as a means of maintaining pressure between cell contacts and wires.

• The snap fit engagement length is .14 inches long with a .1 inch interference to ensure the yo-yo stays together tightly

Table of Specifications: 

Gantt Chart

It Begins

We are team "Fighting Beavers" in MIT's course 2.008. Our task is to create 50 custom yoyo's, utilizing injection molding, thermoforming, and our creativity. Our team is comprised of 6 Juniors in the Mechanical Engineering department:

Alasdair is an exchange student from Cambridge, England through the Cambridge-MIT exchange program. Having lived everywhere from Tanzania to Australia to England, he's now found himself at MIT for the year.

Rory is a captain of the varsity cross country team here. Originally from San Francisco, he is a huge outdoors enthusiast and is always looking forward to venturing out to the mountains as often as he can.

Karla is the Vice President of the Art club here, and has knack for graphic design and anything that can be considered art. Originally from San Diego, she misses the warmth of California every winter.

Akwasi grew up in New Jersey, and has become very involved on the sports Taekwondo team here. Currently also enrolled in 2.009, the mechanical engineering capstone design course, he has his hands full with lab and design courses this semester.

Kelly is from Southern California, and as to be expected, loves swimming, wake boarding, jetskiing, cliff jumping - anything to do with the beach and aquatic sports. It only makes sense that he is also on the varsity water polo team

Devin hails from the Washington D.C. area, but is always looking to travel anywhere that she can - both internationally and here in the U.S. She is also a member of the varsity lacrosse team here.

We've settled on a design for our yoyo based on the MIT fighting beaver, which is our athletics department logo. Incorporating sections of the beaver that will light up, we're excited to see what we can create!