The stretching of a flat sheet of plastic material into a larger shape results in a larger surface area and a corresponding reduction in the sheet s original thickness.
Vacuum forming plastic thickness.
Because all vacuum forming starts from a flat sheet the wall thickness of the formed part will have a variable wall thickness as the material is.
Often confused with injection molding and rotational molding thermoforming processes are.
This is accomplished by putting a piece of plastic into some type of clamping mechanism heating the sheet up to a forming temperature.
The thinning down of the sheet s original thickness is not necessarily uniform.
Because the plastic is fairly low density it is easy to work with small hand tools.
This plastic is very friendly to and its use is well known by the modeling community.
Vacuum forming thin plastics works best they will adhere and take in better detail but 90 abs plastic is what everyone uses for stormtrooper armor and other props when they vacuum form i think westerfields armor uses 65 thick not sure though.
The acrylic petg and polycarbonate sheets are normally clear can be special ordered in colors however the polycarbonate may have to be heat dried prior to the vacuum forming temperature phase depending on thickness.
Engineers often do not really understand plastic forming processes.
The thermoforming process requires a critical forming temperature window and all of our forming machinery utilizes precision electronic controls for maintaining part to part consistency.
Each plastic material has a variety of different properties and they form at different temperatures.
Vacuum forming material selection guide.
One of the most difficult features in thermoforming is the three sided sharp corner in a female mold.
These features are typically needed to allow for part strength retention of material thickness and or esthetics.
Description of vacuum forming simply stated vacuum forming is the process of taking a flat sheet of plastic and changing it into a contoured shape.
Thermoforming vacuum forming and pressure forming are considered thermoforming processes.
All thermoforming techniques are stretching processes.
Vacuum forming plastic choices styrene high impact poly styrene hips generally the best version of thermoforming plastic for modelers.
The key to good part design in thermoforming is understanding the need for a proper size radius or chamfer.
So if 15 mil material is required for a specific project or application the fill thickness will be specified as 15 mils nominal after forming many manufacturers simply utilize heat and vacuum to form the sheets as this is the least costly technique and the most rudimentary to operate and maintain.
