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Compliant Luggage 

Bringing Innovation to Everyday Objects.

Overview

Project

Class

Period

Skills

Advanced Product Design (MIT Course #: 4.041)

Feb - May 2019

Compliant Luggage

Product Design, Laser-Cutting, Implementing New Technologies/Manufacturing with Products, Exploration of the design and manufacturing of products, through narrative, form, function, fabrication, and their relationship to customers

Museum Mounting Board (0.05" thick), Polyester Plastic (0.03" thick), Cardboard

Materials

Objective

Compliant mechanisms are flexible hinges that utilize natural elastic deformation by taking advantage of how certain movements are created. Many of these mechanisms are created through laser cutting and 3D printing techniques.

This compliant luggage prototype looks at how to make the entire luggage compliant so that it can grow and stretch depending on the user's needs. The mid-section of the body utilizes laser cutting techniques to let it stretch taller when adding more clothes. The locking system uses a 3D printed compliant mechanism to lock the luggage. 

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Luggage not actuated

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Luggage actuated

Inspired:

Compliant

& Bistable 

Inspiration for my compliant luggage line was drawn from compliant and bistable mechanisms. Below is a pair of 3D printed pliers printed as one single part in order to minimize assembly and print time. The placement of lack of material allows for space for the pliers to flex and change the overall position and shape of the pliers.

These type of mechanisms are what inspired the design behind my compliant luggage line. By making the luggage out of a single sheet through compliant mechanisms and patterns, one can create luggage out of less material and expand and contract luggage in interesting ways.

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Below are two different types of bistable mechanisms that were created. Both use principles for compliant mechanisms to create two different but stable equilibrium states/positions (aka bistable). Often these switches are used to switch between two different stages on a micro scale.

These sort of mechanisms can be machined with titanium (or any other strong metal or also be 3D printed.

Flextures are common compliant mechanisms that only allow movement in one direction when a force is placed in the motion of the flexure. The flexures in these bistable mechanisms have thin railings that connect the centerpieces to the edges of the center object.

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To collect more information on compliant mechanisms, I wanted to look for and research current patterns that can transform materials to be pliable. The following designs and patterns were laser cut onto cardboard to in order to quickly produce many prototypes and cardboard was also a very cheap material.

Approach

Research

The following patterns were taken are common compliant hinges (wave, brackets, straight, fabric, bowling pin, and geodesic) and were manipulated and tested for merit they could bring to this project. 

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Testing of Different Compliant Patterns on Cardboard

Testing of Different Compliant Patterns on Cardboard

Depending on the cuts and the patterns etched and laser cut into the cardboard, a variety of different motions could be produced. The wave pattern was especially good for creating curves and bends. The brackets pattern was able to create tighter curvatures. 

The fabric pattern was unique in that is allowed the surface to curve and bend in all different directions, although the radius of the curvature was limited.

The geodesic pattern utilized triangles to create different folds that curved in triangular formation.

After looking at these patterns, I looked at how these types of cuts could be applied to compliant systems and creating motion when pulling and stretching the pattern vs folding it.

After the research phase, I narrowed me focus onto the "cross" pattern. I discovered that there were there was an interesting outcome when pulled the pattern apart, and it allowed the length of the entire pattern to stretch and grow in size. The cross pattern can be seen below. 

Prototyping

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Cross Pattern - Close View

I first made a works-like model of the luggage suitcases out of polyester sheets of plastic. I chose polypropylene because of its flexibility and strength to stretch and bend without ripping and breaking. It was also a plastic that was compatible with laser cutting.

Polyester

Prototypes

Using polyester as my first material allowed me to see the extend of how much the luggage could stretch. The first prototype, I made my luggage be a simple rectangle, and eventually I evolved it to include rounded edges to capture a more realistic shape of luggage used today.

Final

Prototypes

For my final prototype, I used museum mounting board (1/8" thick) as my material since it was stiffer than polyester and also its material resembled cardboard more and was less flimsy than the polyester. The polyester also had the problem of snapping back/retracting back to the original state of un-stretched because of its material properties. Thus, the museum mounting board allowed the luggage to expand and stay expanded which more resembled the ideology behind the bistable mechanisms (having two defined states).

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Videos