Vacuum Forming Lab

Objective:

To explore vacuum forming and the effects upon various plastics at different heating cycles.

Procedure:

Two different types of plastic sheets were cut to fit into the clamping device of the vacuum molding machine. The oven was heated to a set temperature and the plastic was inserted with the clamping device. After the plastic began to deform (droop) the clamping device was taken out of the oven and placed over a mold vacuum. The temperature of the oven was set to various temperatures for both types of plastics and the cycle times in the oven varied as well.

Results:

In tabular form.

Summary:

Various problems occurred as we varied the temperature of the oven and the cycle times of the heating process. The oven had to be above a certain temperature to get the plastic to fully form around the mold. If the temperature was not high enough the plastic would not seal on the mold and provide the necessary vacuum. Even though most of the major features were evident, some of the finer features did not receive the need the vacuum. If the temperatures of the oven were too high the plastic sheet would form holes at the vacuum points. Some samples even formed larger holes as the material became to much of a liquid.

Various specimens initially had a grid drawn on the surface. As the parts were formed the grid shifted with the feature. This measurements taken on various features of these specimens showed to be fairly consistent. However, it was hard to be accurate because of the inaccuracy of place each sheet in the same location in the clamping device. Also the clamping device did not always line up with the mold in the same location.