The Drape Forming Process Is One Of The Earliest Forms Of Thermoforming
The Drape forming process has been around since early Egyptian times, where they would heat tortoise shell in hot oil to be formed. It is the most rudimentary type of thermoforming. Essentially, we heat the plastic sheet is until it is malleable, and then "drape" it over a mold. At this point, we use gravity to cause the plastic to shape to the mold. We can achieve very limited detail with this process, as there is no pressure to shape the plastic.
"Power" Drape Forming Process
At ATI, we have perfected a technique we call "Power" Drape Forming. With this method we use articulating clamp frames to increase the normal sag of the sheet, thus more closely approximating the depth of the mold. This has the effect of reducing pressure on the mold surface of the sheet, which results in less "mark-off" being apparent in clear parts.
The clear walls of the elevator shown below are a great example of the Drape Forming Process.