The first step to follow in the vacuum thermoforming process is to start with sketches and get your design engineer involved from the beginning. Vacuum thermoforming is a process very unlike other methods of molding plastics. Because each shape may have difficult areas to form each technician that works on the project may go about forming or attempting to form the shapes a bit differently from the next person. This is why consistency in the process between operators within the plant is vital.
The shape you create may look nice on paper or even in CAD (Computer-Aided Design), however, it may not make a good candidate for the vacuum thermoforming process. It is always best to start with a shape that you know can be molded before you spend a lot of time and money attempting to mold a shape that is unattainable.