Attention to detail is key in all manufacturing. One of the most important details in injection molding is well-designed, precise and high-quality tooling. Injection mold tool is a mold or die that is used to inject material into during the molding process. It is impossible to underestimate the impact that tools have on injection molding. The cost of tooling can be a significant part of the budget for any project. It is important to ensure high quality output.
This post will discuss the design of injection molding tools, how to manufacture them correctly, and why they’re so important.
Injection Molding Tool Design
The design of the tool is an important part of injection molding. However, it also includes many smaller details. All of these factors contribute to the quality of parts produced by the injection molding process. We’ll examine each of these aspects and their role in the design process.
- Robust Tool Design — When designing injection molds, it is important to pay attention to the DFM (design-for-manufacturing) process. The tool must be robust enough to ensure that the opposite sides are aligned and true when the tool is clamped shut. Deflection, where the halves of the tool are not perfectly aligned, can occur if it’s not designed correctly. This can affect the final shape of the product and also cause a problem with injection molding where there is excess material.
- Proper venting of injection molds — Tool Vents are required to allow hot compressed gases to escape the mold cavities. Gas trapped in the mould can cause a variety of problems. Gas can take up the space that resin was supposed to occupy, causing short shots or cavities in solid areas. Gas can also force material to escape the cavity and cause flash. Gas can also become extremely hot if it is not vented. This will cause burn marks to appear on the product, and may affect injection molding cooling.
- Injection molding cooling –The process of cooling is a very time-consuming one in plastic injection moulding and can take up to 75% cycle times. It is important to develop the correct cooling design. The cooling lines should be tailored to the specific part that is being molded. Thick parts will cool slower and require a more aggressive cooling system than thin ones. To reduce pressure drops in the cooling system, cooling lines should be as straight as possible with as few branches as possible. The traditional cooling method is similar to that of a heat exchanger, with long tubes running straight or in a U-shape through the mold. This helps to speed up the cooling process. Conformal cooling is a new alternative approach where cooling channels are closely aligned with the shape of the product being manufactured. The initial costs of tooling are higher, but the cooling efficiency is better and cycle times are shorter.
- Sprue Selection — A sprue connects the nozzle of the mold to the piece that delivers the liquid plastic material. Injection molding, there are five different types of sprue, each lettered with a different letter. These are A, B C D E. They are selected based on the properties of the resin, the type and pressure of the molding machine and other factors.
- Location and number of the gate — This gate is used to inject the resin molten into the cavity once it has been injected through the sprue, and after it has been pushed through the mold runners. It is important to have enough gates in order to fill the cavity quickly and efficiently. Also, gates should be placed to ensure a proper flow of material and a complete fill.
Why Injection Molding Tool Design Is Important
The success of any injection molding project is at risk if the design is not sound and carefully thought out. The mold must not only be accurate and strong, but every detail must also be placed correctly and designed to ensure that the entire process runs smoothly. The tool should also be durable and suitable for repeated usage, as it represents a substantial time and cost investment.
Preferred Tool offers industry-leading services in injection molding, including design and fulfillment of tooling. We will work closely with you to fully understand the project. We ensure not only a successful design, but we also have capabilities such as mold inserts that can make a mold suitable for multiple products. You can save time and money by not having to buy a new mold for each project. Contact us to learn more about how we can help you meet your needs.
