What To Consider When Planning Your Injection Molding Project

What is injection molding?

The injection molding process creates parts and products by pushing molten materials, such as plastic resins or polymers, into a mold to form a specific shape as it cools. The injection molding machine must heat the raw material, maintain sufficient pressure in the mold as it is forced in, cool the molded part and eject it after it cools.

When planning your injection molding project, there are a few things you need to consider

Mold Classification

The mold guidelines used by the Plastics Industry Association (PIA), developed by the Society of Plastics Engineers (SPE), are divided into five categories. Depending on the details of your project, the application of the molding guidelines will be an important determinant of the cost of the mold itself. A key issue to consider with molds is the number of parts you intend to make. Volume is a determining factor in the durability of the tool. In addition to the retained parts, there will be setup parts, test parts injected during the build phase, and more parts to demonstrate the consistency of the mold.

Resin Types

With thousands of plastic resins to choose from, selecting the right one is critical to your part application. You need to consider the purpose of the component and combination product. Are they for wear resistance? High-impact applications? Contain fluids, or anything else? Do they require inserts to hold the parts together or molded tabs for sonic welding? All of these details are important in selecting the best resin for the application.

Surface finish of molded parts

Surface finish options for plastic injection molded parts can vary greatly depending on the part and its material. Determining the best surface finish for a part requires communication between your design engineers and injection molding experts to achieve the desired appearance and performance of the finished part. Determining surface finish is critical to the success of your mold project.

Mold Flow and Analysis

Once you understand the mold classification based on volume and planned resin use, you can analyze the resin flow of your part/mold during the injection process.

Available Budget

The classification and application help determine the budget required for the mold. Producing a larger number of parts requires a mold that is more durable and will last for a period of time. Including this, the design and application may drive more complex features in the mold and require more labor to produce during development.

Time to Build the Mold

The time to build a mold is not set in stone. General guidelines for the schedule will be established at the beginning of the project. This will be based on your stated needs, budget, and available personnel. If you need a faster mold, expect to negotiate at a higher cost.

Project Organization

A detailed schedule for the project needs to be able to be managed efficiently. A well-oiled machine will have a visual schedule that can be easily read to see what is on schedule, what is behind, and what is left before the project ends.

ISO Certification

Having a current ISO certification does not guarantee that a tool store is the best, but it does show that they are quality conscious. ISO certification proves that they want to produce quality and will

Secondary Services

Injection molding is part of the program. Ancillary services may be required to assemble, package and deliver a world-class product to your customers.

Process Quality

Last but not least is the overall quality of the process. The actual tooling is only part of the experience of building an injection molding tool. You should be able to ask questions, have open discussions about time and budget, and feel comfortable at each step of the process. If you feel uncomfortable in the discussion, it may be time to move on to a new partner. Successful partnerships are built on a foundation of trust.

While these things to consider are not the only things to consider, making everything part of the discussion will keep you on track to complete the project on schedule and on budget as agreed and deliver as promised, which will lead to a successful project for your new project.