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Insert molding allows designers to create strong parts that don’t require assembly by adding metal hardware like threaded inserts, bushings, or sleeves. These inserts are bonded and sealed with thermoplastic, eliminating the need for post-molding assembly.
Protolabs hand-loads most inserts for projects with low to mid-volume requirements. For higher volumes, robotics systems may be the best option.
Cost-Effective
Many industries are now shifting to insert molding due to the cost savings it provides. This process combines multiple manufacturing processes into one step, resulting in a cheaper product that’s stronger and more reliable than a standalone plastic part. In addition, insert molding allows manufacturers to incorporate design features that wouldn’t be possible with other manufacturing methods.
In addition, the process eliminates secondary assembly operations like snap fits and gluing, which can save time and labor costs. It also reduces materials costs and production costs. It’s a great option for producing large quantities of parts. It’s also ideal for manufacturing medical devices, such as syringes and implantable devices.
Insert molding can be performed manually or robotically. Regardless of how the process is performed, it’s important to use the right materials. Choose materials that can withstand the injection molding process and that will not distort during the cooling cycle. This ensures consistency and quality. In addition, it’s a good idea to use materials with high conductivity for electrical connections.
Durability
The plastics used in insert molding can withstand vibration and shock and are resistant to corrosion. This helps improve durability over time and also lowers weight, which can be beneficial in certain applications.
Injection molding experts can advise on which inserts are best suited for your application. The inserts can be made of stainless steel, brass, or regular steel, and threaded inserts are available for a range of applications. The inserts can be designed to firmly hold a variety of materials, including metal terminals and fasteners.
The process begins with placing the inserts into a custom-machined injection mold. The molten plastic is then injected and the mold closed. As it solidifies, the inserted inserts are firmly bound within the thermoplastic resin of the finished component. This makes insert molding a good choice for products such as electrical components or medical instruments that require added strength in the threaded areas. It is also a great option for housing units, instrument cases, knobs, and handles.
Design Flexibility
Insert molding allows manufacturers to incorporate metals into plastic parts. These metals offer strength and rigidity, which helps reduce the weight of a finished product. They also help protect plastic parts from damage and wear-and-tear.
Metal and plastic do not form chemical bonds, so inserts must be mechanically bonded to the plastic part. This process eliminates post-molding assembly and separate parts installation, reducing costs and motion waste and optimizing production time.
Unlike overmolding, insert molding does not require a second injection mold to hold the metal component in place. This allows the molder to produce the plastic part and insert in one shot.
In addition to saving on production costs, insert molding also ensures consistent quality and reliability by using magnetic sensors for verification of correct placement. It is important to remember that the gap between molded plastic and metal insert should be narrower than the threaded insert, to prevent loosening. It is also recommended to design the insert with bosses or undercuts to provide increased holding power.
Reliability
Insert molding allows manufacturers to place metal parts inside plastics, eliminating secondary assembly operations and providing robust mating of the inserted component with the molded material. Inserts can be inserted into the mold and then covered with molten thermoplastic, reducing assembly time and cost. Inserts can be made of a variety of materials, including typical metals such as brass and stainless steel.
Because the inserted part is securely held by the thermoplastic resin, insert molding prevents loosening or misalignment. This manufacturing process is ideal for producing high-quality, reliable parts. It eliminates the need for connectors and fasteners and helps reduce size and weight. Manufacturers use this manufacturing method for medical devices, aerospace components, and electrical wires. For example, electrical wires are often encased in rubber to make them safer for consumers and more durable against weather conditions. Manufacturers can also choose from a wide range of molded plastic materials, depending on their intended final products.