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Plastium GmbH

Insert molding –
with plastium

Overmolding with plastic for threads, inserts, and more

Instead of manufacturing pure plastic parts, combining plastic with other metal or plastic components may be relevant for your company. Overmolding inserts such as threads or cylindrical pins with elastomers—technically known as insert molding—is one of the ideal processes for this, which Plastium implements at the highest level as an experienced partner.

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Insert Moulding
Unscrewing technique

Where is insert molding used?

Insert molding is used throughout the manufacturing industry wherever it is necessary to incorporate an additional metal or plastic component into the plastic part being produced. Especially for metal threads, cylindrical pins, or special inserts, the classic injection molding process is often insufficient to meet the highest demands in terms of functionality, aesthetics, and service life of the finished part.

At Plastium, we strive in all cases to implement solutions that are as fully automated as possible, meeting your high quality requirements while optimizing production costs. In insert molding, manual feeding may also be necessary depending on the application; we assess this on a case-by-case basis using our many years of experience and present all possible options to you.

What are the advantages of insert molding in injection molding?

Given the range of benefits—from reduced costs and longer shelf life to improved quality—insert molding is always worth considering as an alternative for producing your components with inserts. Let us advise you on the specific benefits for your project!

1. Cost-effectiveness

A major advantage of overmolding after embedding the insert into the plastic is that the process is completed in a single production step, saving you the cost of additional assembly steps.

2. Reducing the number of assemblies

By directly integrating metal parts into the plastic part, you can minimize the number of individual components required, thereby reducing the complexity of the assembly and shortening assembly time.

3. Longer service life

Once cooled, the embedding of the metal parts creates a strong bond, resulting in increased strength and a longer service life for the product, thereby ensuring higher quality.

4. Design flexibility

Insert molding allows for the creation of more complex designs, as this process enables multiple components to be combined directly into a single part.

5. Improved product quality

In many cases, the use of the insert can improve aspects such as heat dissipation, electrical conductivity, and wear resistance in the finished products.

6. Weight reduction

Reducing the overall weight is particularly desirable in applications within the aerospace and automotive industries. This can often be achieved by using lightweight metal overmolded with plastic.
Unscrewing technique

Screw-out technology – the alternative to overmolding

Depending on the component and application, it is not always necessary to integrate threads or pins into the core of the plastic part. In such cases, forming an internal thread directly within the plastic part itself may be the preferred solution. This is known as screw-out technology, which we also utilize in a wide range of applications.

For many years, we have relied on the unscrewing process, for example, in the production of these components:

  • Rack and pinion gears
  • Steep-threaded spindles
  • Hydraulic motors and gearboxes
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Insert molding – years of experience and state-of-the-art machinery

Just as with injection molding itself, insert molding relies on experience in planning and execution. At Plastium, we have been experts in plastics technology for many years and can provide you with in-depth knowledge of all conceivable materials, applications, and alternatives. Our machinery is designed for parts and components of various dimensions and ensures top quality at a fair price through production made in Germany.

If your company currently uses other methods and processes, we would be happy to work with you to conduct an independent comparison. Especially given market pressures and the need to differentiate yourself from competitors, you will be looking for new ways to stand out with your products. We will guide you through this process—whether as a one-time project or as part of a long-term partnership.

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Comprehensive support from the initial idea to the final product

Whether it’s insert molding, traditional injection molding, or another technique for manufacturing high-performance plastic parts—we provide full-service support with the highest level of expertise. We operate in Germany and Switzerland and support you throughout all phases of your project as a solution-oriented and communicative partner. As with traditional injection molding, we frequently go through these service phases with our customers in insert molding as well:

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Unscrewing technique

Learn more about our specialized processes now

Whether you want to overmold threads or pins with plastic or integrate them directly into the plastic—our experts at Plastium will be happy to develop the ideal solution for you. We take both technical and business criteria into account and provide you with a technically sound overview of how to achieve the best product.

Contact us today and submit your inquiry with no obligation. We are well-versed in injection molding and other advanced plastic processing techniques and will implement your requirements with precision and cost-effectiveness. We overmold a wide variety of materials and would be happy to explain in detail how you can take the next step toward sustainable production with us!

FAQ – Insert molding

Which plastics are suitable for insert molding?
A wide variety of thermoplastics and elastomers are best suited for modern insert molding. The range extends from TPU and TPE to PP, ABS, and polyamide. We would be happy to discuss with you which material is best suited as an overmolding material for your specific application, taking into account its respective properties (such as volume, density, transparency, impact resistance, etc.).
What plastic processing methods does plastium generally offer?
In addition to insert molding and screw-in technology as types of assembly injection molding, Plastium offers both traditional injection molding and modern two-component injection molding for more complex parts and geometries. Assembly injection molding is increasingly used for larger assemblies, while conventional injection molding processes are ideal for individual components made of elastomers.
What types and variants of insert molding are commonly used?
In addition to the insert molding process described above, two-shot molding is a well-established technique in which two different materials are injected in a single manufacturing step. This process is always fully automated, whereas the insertion of the insert can otherwise be done manually. In co-molding, a simultaneous overmolding process is carried out via multiple injection channels to produce multilayer parts.
For which industries is insert molding suitable?
Insert molding has a wide range of applications and offers benefits across nearly all industrial sectors. These specialized plastic components are particularly used in control elements for medical technology, the automotive industry, and electrical engineering. Tailored to your industry, we assist you in selecting the appropriate substrate, discuss alternative molding methods, and much more.
What are the key considerations in design?
When selecting materials, you should only combine plastics that have similar coefficients of thermal expansion. In the mold, the insert should be positioned away from stress points. To ensure consistently safe and optimized production, the mold itself should have uniform and sufficient wall thicknesses.
What specific cost advantages does insert molding offer?
Thanks to the high efficiency and the fast, largely fully automated production process for your plastic parts, you’ll see a noticeable cost advantage even with small production runs. The exact extent of this advantage depends on the specific product and your quality requirements. We’ll provide you with independent, expert advice to help you make the best choice for your specific needs.

Do you have any questions? We’re here to help!

Contact us directly. Whether you have questions about our services or would like a custom quote.

Marco Costantino

Phone: +49 (0)7422 942-134
Email: m.costantino@plastium.com