Dedicated Injection Molds vs. Toolsets

High-quality injection mold tools can be expensive to manufacture. A way of addressing this issue is to use an injection molding toolset. However, a toolset isn’t always the best approach. In some cases, you’d be better off with a dedicated injection mold. Before you decide on a method, consider these key factors: the complexity of the part being molded, the volume of parts anticipated, and the overall budget.

Before digging into these approaches to tooling, it is vital to understand the differences between them.

Overview of Injection Molding Tools

The heart of every mold is the cavity that receives the plastic and forms the part. The cavity is half in the top core and half in the bottom, with the two pieces separating to eject the part. Guide pins slide in bushings to ensure the top and bottom stay in alignment.

Channels in the mold tool — called runners — carry liquid plastic from the molding machine barrel to the cavity. Gates in the runner system control the material flow rate. Heating these channels stops the plastic from solidifying before it reaches the cavity. Mold tools also have channels for cooling water to speed solidification and reduce cycle time.

Dedicated Injection Molds

With this approach, every aspect of the mold design is optimized to meet quality and cycle time goals. In addition to machining the cavity into the upper and lower mold base, the heating and cooling, runners, and ejector pins are all incorporated as needed to maximize output. Meaning all tooling components are designed and manufactured to injection mold that particular product.

Injection Molding Tool Sets

Toolsets for injection molding provide a modular approach to tool design and manufacture. The actual mold cavity remains a custom piece, but the rest of the tool is built from already manufactured mold components. This approach is made possible through the use of master mold frames.

A master mold frame is a design in which runners and gates are machined into standardized inserts that fit within a standard frame. Other components incorporated into the standardized mold frames include leader pins, bushings, sprue bushing, support pillars, side actions, and the ejector system. These do not need re-machined for each new toolset. At the heart of the frame, there’s a toolset that contains the actual mold cavity. This toolset is the only piece of the mold required to be designed and machined to produce a particular part.

Advantages of Injection Mold Toolsets

There are three main reasons for taking the toolset approach:

Cost: There is less design work and less machining involved with toolsets. Additionally, less material is used. All of this equates to a lower tooling cost.
Lead-time: Using standard components can reduce the time needed to manufacture the tool and usually cuts the time required for tooling fabrication.
Flexibility: Master mold frames can have advanced functions — such as side actions with adjustable travel — built-in and ready to use

Downsides of Using Tool Sets

With such clear advantages, it’s reasonable to ask why anyone would choose dedicated injection mold tooling. Two reasons are:

Mold complexity: Sophisticated heating, cooling, and runner systems will need dedicated pieces that toolsets might not create.
Maximizing throughput and minimizing cost: Achieving the shortest possible cycle time involves optimizing every aspect of the mold tool.

Applications for the Different Types of Tooling

Perhaps the most significant advantage of injection molding over other processes is the ability to produce highly consistent plastic parts in extremely high volumes at low piece costs. Fortunately, the injection mold tooling has flexibility, offering either a dedicated injection mold or a toolset. Which tooling options to use will ultimately depend on each project and end-use requirements.

Injection Molding at Crescent Industries

Crescent Industries is a provider of injection molded parts and a maker of injection molding tools. Whether you need high-quality parts molded in plastic or tooling for your injection molding process, we can help. Contact us to learn more about our capabilities and services.