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Injection Molding: Your Questions Answered

If you have an idea for a custom plastic part, you may have a lot of questions about the manufacturing process. Injection molding is a time-efficient and cost-efficient way to achieve the quality part you need. 

Here are answers to some of the most frequently asked questions about custom injection molding: 

How do you know if injection molding is the right process for a product?

There are several ways to manufacture a plastic part. Understanding and knowing the part design, the end function of the part, the quantity needed, and the target part cost will help determine if injection molding is right for you

What is the minimum number of units required for a new molding project?

Due to the high cost of the mold ($10,000 – $200,000), injection molding is typically a good choice if you need a higher volume/quantity of your part. If you only need 100 parts, molding may not be right for you. This depends on your budget and how critical the part design is to your project’s success.

Will a prototype be tested for durability and usability before the mold and lot are produced?

Sometimes yes, only if the customer requests it and or if it’s recommended by our engineering team. There are two types of prototypes: prototype parts made by a 3D printer (extremely small volume) and prototype molds (which will produce exactly what the production mold will produce). The prototype mold is used to produce many parts for sizing and extensive physical testing, prior to production mold build.

How do you know what type of resin is best for a product?

Since there are over 100 different types of resins, we’ll need a good understanding of your vision for the product and what it will be used for. If it needs to have physical requirements like a special color or specific heat resistance, among many other possible factors will help determine which type of resin will meet those needs. Learn more about resins here

How long does it take to build a new mold?

Depending on the complexity of the part, the number of cavities (parts in the mold), and the size of the mold, it can take anywhere from 2 to 26 weeks to build a new mold.

Will the molds for my part be maintained between production runs?

Yes, all molds at Pioneer Plastics are on a PM (preventive maintenance) schedule.

Can the injection mold be modified after the first run of production?

In some instances it can, but not always. It depends on what the change is and whether or not it interferes with the function of the mold. If the modification is major, it may simply require a new mold.

Are there any size limits on parts that Pioneer Plastics can produce?

Pioneer Plastics can produce items as small as a pen cap and as large as a lawn chair. Learn more about our injection mold machines here

Does Pioneer Plastics offer secondary services (like part assembly)?

We offer assembly, in-mold decorating, pad printing, heat transfer decal, and more. Learn about all of the additional services we offer here

The Advantages of Custom Injection Molding:

Plastic Parts Strength & Stability

The injection molding process offers numerous ways to ensure parts are strong and durable. Wall thickness, ribs (for support), and plastic resin selection are just a few mechanical characteristics that support product strength.

Thicker walls are more expensive due to longer plastic injection cycle times and more material but can provide a very durable part. Ribs in key areas can give extra durability where needed and not have the cost issues of thicker walls.

Parts made from engineering-grade resins are able to withstand extreme temperatures, friction, and corrosion. This makes them much more durable than commodity-grade resins, which are typically used in consumer products like packaging.

Environmentally Friendliness

Products that are injection molded tend to last longer due to their quality and strength which reduces the number of molded parts that get thrown away over time.

The injection mold process doesn’t waste materials. When a broken or unusable part is produced, it can be remelted and reused in another mold cavity.

Complex Machining Capabilities

A skilled tool and die craftsman uses lathes, mills, or CNC machining to create the plastic mold. A variety of sizes, colors, shapes, and finishes can be created with our molding machine.

Molding services like insert molding are used to inject resins over another material. An example of this is threaded fasteners that have metal in the center and a plastic shell. Overmolding is most commonly used to enhance the appearance or function of a part, like adding a softer layer of resin to the handle of a part.

It can be used for assembly and decoration, as well. If pieces need to be labeled or decorated, in-mold labeling may be used. Connectivity techniques like heat staking and ultrasonic welding can be used to join two or more parts together.


It is important to pick a partner that handles the entire process – from design to actual injection molding. This is much more cost-effective because the process is handled by one manufacturer from design to distribution.

Injection molding can handle large scale production without compromising quality or adding manufacturing costs. If you’ll be producing a large volume of your part in every run, molding will be a cost-effective option.

Flexibility in Design

All of the needs mentioned above can be solved with good design and engineering. Pioneer Plastics has over 200 years of injection molding company experience in our design team – we know what makes a good part based on what your needs are.

Before the mold is created, we can create a prototype of the part using our 3D-printer. This allows you to experiment with the product and make any necessary adjustments before the mold is built.

The Advantages of Custom Injection Molding
The advantages of custom injection molding

For more than 35 years, we’ve been experts in the design, development, and distribution of custom plastic parts. Contact Pioneer Plastics to get a quote for custom injection molding services.

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