Insert Molding

What is Insert Molding?

The technique of molding or shaping plastic pieces around non-plastic parts, or inserts, is known as insert injection molding. The inserted component is usually basic, like a thread or rod, although inserts can be as sophisticated as a battery or motor in other circumstances.

Insert molding also integrates metal, plastics, and other materials and components into a single unit. For example, engineering polymers are used for enhanced wear resistance, tensile strength, and weight reduction, while metallic materials are used for strength and conductivity.

Insert molding is commonly used to include one or more threaded metal inserts in a plastic part that is meant to join with another part in an assembly. However, plastics may not have the mechanical qualities necessary to sustain the forces required to join two pieces.

For example, thread in a plastic part might wear out with repeated use, resulting in a failed item. Metal inserts enhance the plastic's characteristics and ensure the portion stays fastened over time.

Using this mix of plastic and metal, designers can use plastic's weight reduction and metal's robustness.

Insert Molding Process

The injection molding process remains the same regardless of which equipment is utilized. The machine's barrel part is heated in the first stage. Placing the pellets, or grains, into a hopper is the next step.

A screw mechanism inside the hopper drives the granules into the heated barrel, where they are melted down. Next, a split die chamber mold cavity is injected with molten plastic. The cavity is clamped shut once it is full.

Water and other fluids circulate through the mold's cooling system, removing the heat. The portion is held in the mold under extreme pressure until it hardens entirely. Finally, the part is taken from the mold once it has solidified.

The most frequent material utilized in the injection molding process is thermoplastics. On the other hand, elastomers, biodegradable polymers, and thermosets can be employed. ABS, polycarbonate, and polypropylene are additional materials that can be utilized for injection molding.

The insert molding process needs exceedingly tight tolerances to properly create the plastic parts being made. The tiniest misalignment can cause the molding process to fail. As a result, manufacturers may use a different type of plastic during the fabrication process to keep prices down.

Costs can be kept low by researching the benefits and drawbacks of various varieties of plastic. Not all plastics, for example, can be recycled; nevertheless, polystyrene, polyethylene, and nylon can.

Recycling and reusing plastics is one of the most cost-effective ways to save money during manufacturing.

Advantages of Insert Molding

• Increases Design Flexibility: Insert molding enables nearly limitless permutations, which benefits designers. Overmolding, for example, allows a 3D circuit board to travel freely inside and outside, into holes, and up walls of the part, with the plastic connecting it.
• By combining various components with thermoplastic, insert molding helps reduce assembly and labor expenses. For example, a single stamping can be perforated after overmolding to produce many circuit routes.
• Increases Reliability: Because each part is firmly held in thermoplastic, an insert molded component avoids loosening, faulty terminations, misalignment, and other issues, resulting in increased component reliability. Vibration and shock resistance are also improved using thermoplastic resin.
• Insert molding produces components that are smaller in size and lighter in weight because it eliminates the need for connectors and fasteners and combines the physical strength of metal inserts with resin.
• The technique offers a high production rate and requires little to no additional processing after the injection molded object is completed.
• Injection molding is the method of choice for producing exceedingly intricate products that can't be made any other way.

Applications of Insert Molding

• Military hardware
• In-mold labeling (IML) and in-mold decorating (IMD)
• Tube valves and needle hubs
• Encased bushings, studs, and tubes
• Appliance knobs, assembly knobs, and control knobs
• Threaded fasteners
• Electrical components and electronic gadgets