Molds for Lenses
Molds are used to shape the lenses. Two types of molds are uses to create the plastic lens. They are sealed together with a gasket. The gasket makes sure a measured distance exists so the mold can be filled. Lenses are created by using a liquid monomer that is poured into the molds. The curve of the molds indicates the type of shape of will be created. Below is the steps to create the molds for lenses.
Clamping: This is where both of the heavy mold halves are pressed together and secured. This creates the form for the product. Typically, one half of the mold is stationary while the other half slides into place.
Injection: The plastic pellets are funneled from the hopper into the heated spiral press where they are melted and then injected into the mold cavity.
Cooling: As soon as the molten plastic hits the mold it starts to cool. Complete cooling of the plastic product depends on the plastic used, wall thickness, and size. The mold walls cannot be taken apart until the product is solidified, or it will become deformed. Coolant can be pumped through the mold channels to expedite cooling.
Ejection: The product needs to be taken out of the mold after it has hardened. This can be done mechanically or with air pressure. Releasing agents are often sprayed on the mold walls prior to being clamped to help release the product without causing damage.
Finishing: These are the perfecting stages that happen after the product is released from the mold. They range from cutting and painting to adding rivets and other parts to the item.
