Plastic injection molding is a process that allows for the quick and affordable production of plastic products and parts. The type of plastic used to produce a part is the most crucial aspect in just about every facet of the plastic injection molding process.

Determining what goes into your plastic materials cannot be overlooked! It’s not only essential to understand what you need to use, but also the “why” of material selection and how it can affect the product and manufacturing process. We have put together these points to consider when choosing a resin for your product.

You might be asking yourself:

Why it’s so important to select the right material for plastic injection molding?

There are two major points you should consider: your end product and your budget. The material you use will play a role in the end function and performance of any product you create through plastic injection molding. If you choose the wrong material, your product might not perform or could break easily. Save yourself money in the long run by taking the adequate time to determine the manufacturability of your part.

Next, properly allocate your budget. Cost is one main driver when making your decision. While you may think you are saving money by using an inexpensive material, you are taking a risk that your product will not function properly.

On the other hand, if your end product doesn’t require the highest-end premium materials, don’t use them. There is no reason to increase your production costs when the end result doesn’t require the expense. Always consider the cost of ownership of a product when setting out to begin production. Don’t be afraid to ask your molder. Plastic injection molders, such as New Berlin Plastics, are more than willing to offer non-bias suggestions. We are the experts!

In addition to your budget, there are a number of other items that you should consider. The chosen material will directly affect all aspects of the part, such as:

  • Color and Appearance
  • Strength and Durability
  • Rigidness or Flexibility
  • Reactivity to Other Materials
  • Resistance to Heat or Corrosion

For example,

If your goal is to create a microwave-safe dish, but you don’t choose materials that are of “Food Grade” or able to withstand microwaves, you are going to end up wasting a lot of money. Don’t get stuck with a product that will ultimately need to be replaced.

There are seven common resins used in the industry you can choose from when manufacturing your products.

  • ABS: ABS is a common thermoplastic that has a wide range of uses in a variety of end products.
  • Acrylic: Acrylic is often used in the plastic injection molding process due to its ability to mimic the appearance of glass.
  • Epoxy: Epoxy is a thermoset resin that can offer your products a very high strength, as well as heat resistance and the ability to withstand a wide variety of chemicals after curing.
  • Polycarbonate (PC): Polycarbonate is a transparent thermoplastic that is widely used throughout the industry thanks to its ability to offer some of the strongest and most shatter-resistant construction available for plastic injection molded products. You will find polycarbonate resin behind many of the items used in your kitchen.
  • Polyethylene (PE or PET): Polyethylene is a strong thermoplastic with an incredibly high melting point. Polyethylenes are also very viscous when compared to the other resins on this list, which allow for different types of plastic injection molding.
  • Polypropylene (PP) : Polypropylene is the most commonly used resin in consumer-packaged goods. This will probably be the resin of choice if you intend on creating a wide variety of consumer products.
  • Polystyrene (PS): Polystyrene is best used for plastic injection molding where the budget is a primary concern. While it is the least expensive option available to you, there are trade-offs where strength and other qualities are concerned.

Ultimately, you want to ensure that you take into account the budget you have worked out in advance so that you don’t blow your money on premium materials when they aren’t necessary.

Once you have reviewed all of the factors discussed above, then you are ready to start prototyping. Otherwise, you might make a decision that will require further expense and a product you cannot sell to the public.