How to Make Plastic Molds

In order to mass produce your product or part you’re going to need a mold. While hobbyists can make their own molds on a small scale, in order to mass produce your product you will need to outsource your mold making and manufacturing to companies specialising in mass production. If you’re unsure about whether you need a plastic mold, or one made from a different material please get in touch and we’ll guide you in the right direction.

Mold making can be an intricate and expensive process, so it’s important to work with a company that has years of experience and contacts around the globe allowing them to find a manufacturing facility that is the closest fit possible for your project, and which will allow you to get a quality mold made quickly and affordably.

There are a number of stages involved in making a plastic mold that will function as the base for replicating your product or part many times over. Below is a brief overview, but for more information about the process please get in touch, we’d love to hear from you!

How are molds made from plastic?

The master part or prototype

Before a mold can be created there needs to be a template or prototype created which the mold is created from. It’s important to prototype your design before moving onto the molding stage, as often there are issues with your initial design which can only be picked up by prototyping, and which can save you thousands of dollars down the track in having to re-engineer molds or wasted manufacturing time and materials if mistakes are only picked up at a later date.

In order to prepare the master part ready for molding it is given a thorough clean, making a point to get rid of any tiny dust particles which will bubble your molds. After you have cleaned and dried the master part, a release agent is applied. This will help in getting the item out of the mold once it’s created. The master part is then coated with an agent that prevents bubbling, by preventing any air from escaping from around the product as the mold is forming. Lastly, the master part is placed in a container which is heat safe and which forms the basis for the plastic mold.

Melt the reusable molding materials

The plastic molding material is then melted at high heat and poured over the master part. On a small scale hobbyists will frequently use a microwave to melt molding materials, by setting the timer for 15 – 20 second intervals, and repeating the time in the microwave until the plastic is sufficiently melted. Alternatively a double boiler may also be used. In industrial applications the molding materials are heated to a degree which is not safe for regular handling, and is processed by manufacturing machines.

Pour the melted material over the master part

Finally the molding material is poured over the master part, and left to set. Once hardened, the master part is removed from the mold, ready to be used in the mass production process.

Keep reading: Common problems and defects with plastic injection molding