Vacuum Forming

Question 1

What is vacuum forming

Answer 1

Vacuum forming is where a sheet of plastic is heated to a forming temperature and then stretched onto a surface mould and forced against the mould by a vacuum. This process can be used to form plastic into permanent objects and example could be protective covers.

Question 2

Problems when using Vacuum forming

Answer 2

There are some problems when using the vacuum forming process. Absorbed moisture can expand which can form bubbles within the plastic’s inner layers. This really weakens the plastic, however this can be solved by drying the plastic for an longer period at a high temperature. Webs can form around the mould, which is due to overheating the plastic and as a result must be carefully watched. Webbing can also occur when a mould is too large or parts of the mould are too close together, also objects that are formed often stick to the mould.

Question 3

Types of vacuum forming

Answer 3

There are numerous patterns you can make with vacuum forming. The most useful way to use vacuum forming is to take a small item then replicate it many times and then vacuum for the new pattern to create a more cohesive form. The vacuum forming helps bond the individual pieces together and make a mould out of many pieces that can easily be replicated. The types of vacuum forming are;
Cast aluminium moulds
Machined aluminium moulds and composite moulds.

Question 4

Finishing methods

Answer 4

Once a vacuum forming has been created out of a sheet of plastic you will need a finishing operation to turn it into a usable product. Common vacuum forming finishing methods are: 
Guillotining 
Drilling
Roller cutting
Press cutting