Manufacturing
After the Twist had been designed, a production method had to be found. Here you can find a brief overview of how the different parts are manufactured and why.
A decisive factor in the choice of production method is the material and desired production volume. In this case, the material is determined to be plastic. There are multiple different options regarding the production of plastic products. In the case of the Twist, injection moulding is the best option.
Producing plastics
Material
A very important aspect of The Twist is the material that the bottle is going to be made of. By setting requirements, failure modes and load conditions, many materials were eliminated. In the end, two-third of the bottle is going to be made of Polymethyl methacrylate (PMMA), which is going to be the transparent bottom half of the twist. Next to this, a trhird of the bottle is going to be made of Polypropylene (PP).
Figure 1 - Characteristics of thermoplastics and thermosets
There are three categories of polymers of which need to be chosen: thermosets, thermoplastics and elastomers.
The material should comply with the requirements that were set. This is to be sure that the bottle fulfills all needs and demands, without failing prematurely. By applying these requirements, a final material is found. The material must be suitable for injection molding, since that is the most efficient way of mass producing plastic products of the desired size and quantity.
Mould
When designing the mould for the top rotating part (part 2), many things have to be considered. Mainly screw thread and parting lines are things that are essential for this part of The Twist.
Mouldflow
In this section, we will discuss the simulation model. See also the full report on the process and runner calculations.