Vacuum forming is a process that's used for forming plastics. The plastic material is heated, stretched over a mold, then held tight by a vacuum. By the end of the process the plastic is sucked down to conform to the mold. There are both advantages and disadvantages to this manufacturing method.
One of the disadvantages of vacuum forming is the depth of the plastic pieces that you can use. According to plasticingenuity.com the plastic pieces that you can make with vacuum forming need to be relatively shallow, as deeper pieces can warp or twist in the process. Typically vacuum forming isn't used to create deeper pieces, but when it is special precautions have to be taken to stretch the plastic beforehand to prevent warping, which adds to the cost of the manufacturing.
Vacuum forming plastic can also lead to distortion as the material forms bubbles. The bubbles form as a result of air pockets that get into the material while it's being stretched and molded and they can ruin the pieces produced. These bubbles form from additional moisture being absorbed into the plastic, so it's very important that if vacuum forming is the chosen manufacturing technique, the environment is strictly controlled so no added moisture messes up the process.
It's a fact, according to plasticingenuity.com, that vacuum forming cannot create as many pieces as quickly as other processes. The vacuum forming process is relatively cheap, but the trade off is that it has to be strictly controlled and that it's also relatively slow. Additionally, the speed of the vacuum molding has to be controlled because if the piece is left to sit too long it can spiderweb into cracks due to the long exposure to the necessary heat.
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