Monoblock Chair   

Feb - Apr 2013, Hongkong

'Bac' Monobolock Chair is deisgned in Hongkong. When designed this chair, we did research in Hongkong and we were attracted by the stacking plastic chairs in Dapaidang (small restaurant). These chairs work well in Hongkong because Hongkong is famous for its limited and expensive land. Stacking plastic chairs can help save space and they cost less than other material chairs.

My partner and me designed this chair inspired by cheap plastic chairs capable to stack in Hongkong. 'Bac' is designed for public area such as schools. We observed people's behaviour on chairs and found out that young people love to sit reversely. So we designed this chair which be sitted in reverse posture comfortably and people can write and sleep on it as well.

Design the way people interact with chair.


Hongkong, well-known metropolis in Asia, has the most expensive land because of its mass population and relative small area. In this furniture class, we began with discussing the monoboloc chair used in Da Paidang, which means the plain restraurant in the middle of some small roads between city bocks. We observed and analysed the way they save their space and their cost. To solve the space problem, common method is to stack chairs. And to reduce cost, restaurant owners prefer to use cheep plastic chair.

Design Requirements

In this project, we are required to apply injection technics which is broadly adopted to manufacture plastic products. Injection molding is a manufacturing process for producing parts by injecting material into a mold. Some features needed to be contemplated while designing objects produced by this way.

Stacking Ways

Another requirement is to design a chair capable to stack. This is caused by the expensive land of HonKong. To achieve this requirement, we consulted many existing famous chairs as well as chairs in the stores. We concluded that there are generally three common ways for stacking: front-and-back, wrap and spin showing as follows:

Initial Concepts - Sketchings

We finally chose the third idea. It's a simple idea. When we thinking about the relationship between chiars and users, we found that many people, especially young people, sit as a reverse posture spontaneously. So we think out this chair designed for school which can be used for writing and sleeping as well.

Testing different angles

We tried to figure out the best configuration of this chair.Three parts of the chair’s profile is crucial. The seat’s profile takes responsibility for stacking, and the two angles of the back are responsible for the comfort for writing and sitting respectively.

Models for stacking testhing

We drew and calculated angles on the paper, and then made some physical models out of hardboard to see if it would work out and to see if it is good-looking. We also use these models to test if it can work in stacking. And it succeeded.

Testing for manufacture

It took us one week to try some simple paper models to testify if it can be manufactured properly. Finally, we successfully made a model from tissue and white glue through the way simulating the injection process.