Insert Injection Molding

Injection Injection Molding is one of the most famous manufacturing processes that can be further divided into specific categories like overmolding and insert molding. Insert molding alludes to an injection molding process that helps in encapsulating a component, such as an electronic component of a circuit board or cable, into a plastic part. Before the molding process, the component gets loaded into the mold, and then molten plastic is injected into the mold. Once the plastic solidifies, the component in the mold gets lock into the plastic. Usually, thermoplastic resins or polymers, along with low-pressure molding techniques, encapsulate components into plastic packing.

Like many other injection molding processes, the application possibilities of insert injection molding are seemingly diverse or somehow endless, from manufacturing simple (couplings, knobs, and filters) to complex (electrical components) parts. Because of the massive array of applications associated with insert molding, a wide range of industries are open to streamlining this process, replacing other conventional modes of injection molding. Apart from this, inserts are of different types, which get used for fastening and locating plastic parts with other assemblies. It is also likely to have variations of different inserts on a single part. Here is a list of the most common insert applications: dowel pins, spring-loaded clips, male thread, female thread, and electrical contacts.

Differences Between Overmolding and Insert Molding

The general concept of insert molding and overmolding is quite similar; however, there is a considerable difference between these two processes. Typically, overmolding is a dual-step process in which two separately molded parts get joined to enhance and improve the product's quality and features. Two parts are permanently joined to each other but do not involve complete encapsulation. Let us now understand the difference regarding processes, speed, and cost:

1. Processes Specifics

The processes have many similarities but are still not identical. For example, in overmolding, a plastic component gets manufactured using injection molding. After it gets cooled, the component is placed into an overmolding tool and then coated with molten resin or thermoplastic. On the other hand, insert molding uses a pre-formed part, often metal. The part is manually loaded into the mold and overmolded by molten resins or thermoplastics. That is how insert molding offers complete encapsulation of molded parts, and two molded parts get molded simultaneously.

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2. Speed of Injection Molding

As far as overmolding is concerned, it involves an aluminum mold with no heating or cooling lines running through it. Nonetheless, the cycle time is a bit longer, allowing molders to ascertain the essential quality of parts, cosmetic concerns, and pressure. When all the molded parts get joined, the overmold tooling is assembled to press. Thus, overmolding is more time-consuming than insert molding. At the same time, insert molding is a comparatively faster and quicker process. As two plastic materials get molded simultaneously, the time taken is low. In addition, the process requires less arrangement if compared to overmolding, which also reduces the time.

3. Costs

Overmolding is a double-shot process, while insert molding is a single-shot process. Though both techniques are of lower costs, insert molding is a bit cheaper than overmolding. The reason is that it eliminates secondary assembly operations, including gluing, snap fits, screws/fasteners, etc.

Benefits of Insert Molding

The trend of insert molding is rapidly growing among the manufacturing industries. Wide range of applications, lower costs, and simple process; all these factors add to make the insert molding process convenient for manufacturers. Here are some most familiar benefits of insert molding:

1. Assembly Cost Reduction

Insert molding is a highly cost-effective manufacturing process. The foremost reason behind this is that it is a single-shot process only. Therefore, the need for post-molding assembly, which usually happens with the separate metal element, gets eliminated. Similarly, separate parts installation adds in demand for labor, includes motion waste, and requires more production time and additional equipment & functions. But then again, all these arrangements are not more needed in insert molding. Hence, these are the reasons that justify the lower costs of insert molding.

2. Material Cost Reduction

As discussed earlier, overmolding is a double-shot process in which the plastic part is molded and then overmolded. That is how the size and the final product's weight are comparatively heavier than the final product achieved due to insert molding. While being a single-shot process, insert molding brings down material costs and makes the material wastage almost negligible. Consequently, like the micro injection molding process, the reduced weight and wastage, smaller size, and lower manufacturing time reduce the costs of the insert molding process.

3. Flexibility and Reliability Assurance

Insert molding provides considerable flexibility and reliability assurance. For example:

It empowers designers to add features to plastic parts, making them more grounded, sturdier, and more reliable than local plastic areas.
It offers improved product design by incorporating features impractical with plastic alone.
It is helpful in metal to plastic transition to make parts more proficient – decreased weight, reduced production expenses, and eliminated corrosion.

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Insert Molding Application across Industries

Being cost-effective, faster, reliable, and flexible, insert molding offers many applications across different industries. Along the same lines, here are some of the common industries in which insert molding plays the most influential role:

1. Medical Industry

Health and care sector is hugely relying on products manufactured using insert molding process. Ranging from simple devices to intricate and sensitive devices like delivery equipment for stents, sutures, and implants, all medical devices manufacturing is being done using insert molding. Besides, electronic devices with excessive use in the medical industry involve certain parts manufactured using insert molding. The most common products of insert molding include:

Medical Knobs.
Medical Enclosures.
Tubes.
Medical equipment component.
Prosthetics.
Blades and surgical instruments.
Dental instruments.

2. Electronics

Like other industries, electronics industry is finding the use of insert molding beneficial. Encapsulation of wire plugs and threaded inserts in molded parts are typical examples of insert molding applications in the electronics field. Electronic industries are well-convinced over insert molding instead of working with assemblies and using solders and fasteners. Accordingly, the following are the typical applications of this type of molding in the field of electronics:

Digital control panels, assemblies, and knobs for appliances.
Threaded fasteners.
Encapsulated electrical components and devices.
Military equipment.
Encapsulated brushings.

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3. Aerospace Industry

The typical applications of insert molding in the aerospace industry include seating of aircraft, stowage bin latches, handles, lavatories, and user interface switches. The key advantages of insert molding in the aerospace industry include:

Decreased weight of aircraft.
Increased durability and strength.
Elimination of additional and undue assembly and manufacturing steps.
Reduced assembly time and manufacturing time.
Improved and enhanced industrial design.

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Conclusion

Insert molding is one of the influential and famously adopted molding methods. The reliance of diverse industries over the manufacturing of specified products massively belongs to this manufacturing process. Typically, overmolding and insert molding are commonly considered identical processes; however, there is a clear difference between them, as mentioned above.

As far as the global market size is concerned, according to the verified market research, the global insert molding machine market is growing substantially, and the market would significantly expand from 2019 to 2026. In short, insert molding holds a better capacity to fill up the modern needs of industries, which is the very reason for expanding its use.