Complex Molding Techniques For Complex Parts

Injection molding is perhaps the most versatile process for creating custom plastic parts. By utilizing the complex molds involved in this process, manufacturers can create intricate parts in a variety of sizes, colors, shapes, and finishes. 

Everything from small buttons to washing machine tubs can be created through this process.

Custom molds are made out of metal using lathes, mills, or CNC machines. This state-of-the-art machinery ensures that the mold is made to the precise measurements of the part. 

Building the Custom Mold: Exploring Specific Features

Most molds are built using a traditional straight-pull. This is when the mold can open and the part falls out without any help. Sometimes, parts that require specific features or functions may require a more complex mold or a longer ejection process. 

In order to achieve certain features, more advanced mold design is sometimes necessary. 

When undercuts on a part are necessary, cams and/or lifts can be used. These cams and lifts enable parts of the mold to be moved out of the way after the molding cycle enabling the mold to open and the part to come out of the mold.

Mold with cams
Mold with lifts

Some parts may require a small hole going through its entirety. Features like these can be solved with core pins that are affixed to the mold. This allows the melted resin to form around the pin and harden to form the opening. 

Insert molding and overmolding are typically used to achieve effects that a typical production mold cannot achieve, like enhancing the appearance, function or adding a layer to the part. 

Insert molding is a process of injecting a plastic resin over another material, typically metal. One popular example of this is threaded fasteners. Overmolding is used to add an additional layer of resin to an existing plastic part, like adding a soft layer to the handle of a tool. 

Cover panel with brass inserts

Multi-cavity molding is used for producing large quantities of parts because the mold can produce multiple parts in one single shot. These types of molds are more expensive to make but can lead to piece price savings due to a faster production time.

After the mold is built, tested, and perfected, it is transferred to the injection molding machine for production to begin. 

Injection Molding Techniques 

The initial injection molding process consists of injecting plastic (heated to a liquid state) into the mold cavity, where it cools and forms into the custom part. 

Secondary processes like assembly and decoration are used if pieces need to be connected, decorated, or labeled. Decoration includes hot stamping, labeling, and printing on the parts.

Foil hot stamping in-mold label
Drink-n-Plate in-mold label

Ultimately, the design of the part will determine the design of the mold and the techniques used to produce it. From design to distribution, Pioneer Plastics has a streamlined production process that saves time and money. 

Contact us today to get a quote for your custom plastic part. 

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, injection 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 molding 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

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.