What Is Insert Molding? Process, Considerations & Applications

Insert molding refers to an injection molding approach wherein inserts, especially metal, are added into the mold before injecting plastic. When the plastic cools down, the insert becomes an integral part of the finished product. Many industries utilize this process as it helps manufacture durable, lightweight, and strong parts. Simply put, this is one of the procedures to mold plastic around any non-plastic item. 

Though metals are general inserts, but plastics, ceramics, and electronics are also used in insert injection molding. It is among the most affordable processes in mass production. This industrial approach has transformed the latest manufacturing techniques. In this blog, we will discuss its procedure, applications, and considerations in detail.

Step-By-Step Process of Insert Molding

It begins by preparing the workspace and loading the materials. Before an insert molding expert applies the molding material, particular components are placed into the mold. Meanwhile, ensure that inserts are in their locations to maintain their orientation and place throughout the material injection. Here is a step-by-step version of the insert molding process, 

Step 1: Loading of inserts into the mold 

Sometimes, experts use automated machinery to place the inserts accurately and consistently into mold cavities. If you do not have budget issues and are planning high-volume manufacturing, automated machines are the fastest option. 

Inserts can also be loaded manually for certain prototypes or products. Professional operators put them in suitable locations within the mold. This procedure is more affordable and preferred for low-volume manufacturing. 

Step 2: Injecting molten plastic into the mold

In insert molding, this procedure usually happens under high pressure, guaranteeing an even flow of plastic around inserts while filling the cavities.

Step 3: Opening the mold and remove the molded part 

The mold is opened after the plastic has adequately cooled and solidified. As per the equipment used, it can be done manually or automatically for insert injection molding. After the molded part is combined with the inserts, it is cautiously separated from the mold.

Step 4: Detaching molded part from the Sprue

During molding, additional plastic material known as runners or sprue is usually created because of the injection. It can be detached from the desired molded part through cutting or trimming. Please note that it is one of the most important steps in insert molding.

Step 5: Post-processing 

This step might be necessary according to the product’s special requirements. This may involve surface finishing, quality machines, or additional machining to confirm the component fulfills the preferred conditions. 

Factors To Consider in Insert Injection Molding

The process is a bit complicated and that is why, you must consider some factors before undertaking insert molding. It is important to extend your understanding of this facet for the best results. So, enlighten yourself with some important below-mentioned factors,

1) Positioning Of Inserts 

Any alteration in the location or position of the insert hinders the insert moldingprocess. Hence, you must position them with all required tools and keep the molds unharmed throughout the procedure. 

2) The Cost

Another relevant factor is the production cost. You must also review the cost of materials, maintenance, labor, and operator’s costs. Moreover, stay updated with any possible changes in the piece-by-piece rate of components and materials. 

3) Insert Types

This is among the most basic aspects to keep in mind before starting the process. The chosen type must withstand extreme pressure and temperature usually encountered during this approach. 

4) Features Of Undercut

Undercut features are an essential aspect to consider for inexpensive and effective insert molding. Keep in mind that they offer excess power to molded components. 

5) The Mold Design 

The usefulness of the mold design offers greater security to mold inserts, especially from the heat and pressure which could ultimately damage them. 

6) Wall Thickness

It is required during insert injection molding as the pressure applied by the closed mold’s clamping force will cause the outward flow of the insert. Any variations can affect the product’s functionality and design.

Applications Of Insert Molding

Insert molding can produce multi-material, strong components and boost product performance and layout. Therefore, many industries employ it as the go-to approach for manufacturing components. Let us look at some of them, 

1) Automotive

A huge part of the automotive industry relies on insert molding. The process has substituted metal parts production with plastic molding. It is an affordable alternative with increased durability and ease of replacing automotive parts. 

2) Aerospace

This industry utilizes insert molding for lavatories, seating aircraft, user interface switches, and handles. Additionally, it is used to create other parts like interiors, controls, and communication. This helps lower aircraft weight with manufacturing and assembly time. Insert molding also improves the durability and strength of aircraft components.

3) Medical Tools

It facilitates cost-effective and better manufacturing and production of easy to complex medical tools. The insert molds are utilized in sutures, implants, surgical instruments, prosthetics, knobs, enclosures, electronic devices, and blades in hospitals. 

4) Defense

The insert injection molding process aids in generating efficient, lightweight, and inexpensive military precision instruments. It includes the production of handheld communication tools, battery packs, weaponry, monocular and binocular housing, and munitions.

5) Consumer Electronics

The insert molds are most extensively applied in the consumer electronics industry. It is used in solders, fasteners, coils, cords, knobs, electric wires, and home appliances. 

Conclusion

There is no denying the fact that insert moldingis a revolutionary manufacturing strategy offering many benefits in several industries. Modernizing production procedures equips manufacturers to create efficient, innovative, and robust products. It is undeniably a precious tool to reduce prices, refine product design, and amplify product functionality.

There is a reason why insert molding design is considered a better procedure than other molding types. Being the latest available technology, it can work with an extensive variety of materials and produce complicated part geometrics. As a result, it offers systematic manufacturability and client satisfaction. For better results, you must hire a reputed insert molding professional with years of experience in the preferred industry.