With its unique properties, including longevity and weather resistance, plastic is now an essential material used in the production of countless consumer and commercial goods. Statistics show that global production of plastics has increased from just 100 million metric tons in 1989 to 348 million metric tons in 2017. Not all plastic products are solid, however. Many are, in fact, hollow. When creating hollow plastic products, manufacturers often use a process known as dip molding.
What Is Dip Molding?
Dip molding is a plastic process that’s used to create plastic products or parts with a hollow interior. It involves submerging a mold in a bath of heated plastic and allowing it to cool. Once cooled, the hardened plastic exterior is separated from the mold. Because the mold fills the space inside the plastic, dip molding creates products or parts with a hollow interior.
The Steps to Performing Dip Molding
There are different ways to perform molding, but a typical dip molding process consists of the following steps:
- The mold is heated.
- The mold is fully submerged in a bath of heated plastic.
- After allowing the mold to soak in the heated plastic for a sufficient length of time, it’s pulled out.
- Depending on the particularly application, the plastic-coated mold may then be cured.
- The manufacturer allows the plastic-coated mold to cool at room temperature.
- Finally, the manufacturer separates the solidified plastic shell from the mold.
Dip Molding Solution
Most dip molding processes are performed using plastisol. A type of plastic consisting of PVC particles suspended in plasticizer, it’s inexpensive and easy to use. However, manufacturers may use other bathing solutions for dip molding, including polyurethane, silicone or latex.
Dip Molding for Metal Parts
While manufacturers typically perform dip molding to create hollow plastic products or parts, some use this process to add a layer of plastic over a metal product or part. This process is known as plastic dip molding, and it differs from conventional dip molding by eliminating the need for a mold. With plastic dip molding, a metal product or part is submerged in a bath of heated, liquefied plastic.
The purpose of plastic dip molding is to improve the performance of metal products and parts. Without a plastic coating, metal products and parts are susceptible to corrosion. Dip molding protects against corrosion-related degradation, however, by adding a weather-resistant layer over the surface of the respective product or part. In addition, the layer of plastic protects the underlying metal from scratches.