Injection molding is a high-volume manufacturing process for plastic parts. In this method, thermoplastic resin Injection molding is a high-volume manufacturing process for plastic components. In this process, thermoplastic resin pellets are heated to a molten state and injected under pressure into a precision metal mold. Once the material has cooled and the component has reached sufficient rigidity, the finished part is ejected from the mold.
Although injection molding requires an upfront investment in the injection mold, it provides low unit costs and relatively low material waste compared with subtractive manufacturing methods at high production volumes. This makes it an effective manufacturing solution for applications ranging from medical technology and consumer products to automotive components.
Injection molding includes several process variants. Thermoplastic injection molding, using materials such as ABS, polypropylene, polycarbonate and nylon, is the most common method. Other processes include liquid silicone rubber injection molding, or LSR molding; overmolding, in which a second material is molded over a previously manufactured component; and insert molding, in which an insert, such as a metal component, is placed in the mold and plastic is injected around it.
Gelecta’s expertise also extends to metal injection molding, or MIM, for complex metal components. MIM combines the design freedom associated with injection-molded parts with the strength of metal, enabling the cost-efficient production of small and intricate metal components.
Design and material considerations
Successful injection-molded components require careful design for manufacturability. As part of the tooling project, the manufacturability of the component is evaluated through a DFM analysis before mold manufacturing begins. Depending on the requirements of the project, the design process can also be supported by injection molding simulation to assess factors such as mold filling, material flow, pressure, weld lines and the risk of warpage.
Key design considerations include:
Uniform wall thickness
Keep the nominal wall thickness of the component as uniform as possible to reduce sink marks and warpage. Rib thickness is typically designed at approximately 40–60% of the nominal wall thickness of the component.
Draft angles
Add a slight draft angle, typically 1–2 degrees, to vertical surfaces so that the component can be released from the mold more easily.
Reducing undercuts
Minimize features that prevent the component from being ejected directly from the mold. Where undercuts are required, they can be produced using side-action slides or movable cores.
Gate placement
Gates and runner systems should be designed to fill the mold cavity in a controlled and even manner. The gate type and location are selected according to the size, material, geometry and cosmetic requirements of the component.
Modern injection molding can achieve tight tolerances, in optimal conditions even around ±0.08 mm, together with high repeatability. However, resin shrinkage, cooling behavior and gate vestiges must be taken into account during the early stages of product development.
Material selection is equally important. Common plastics such as ABS, PP, PS, PC, POM and nylon provide different combinations of strength, flexibility, wear resistance and thermal performance. Polycarbonate, or PC, is strong and transparent. Polypropylene, or PP, offers good chemical resistance and cost efficiency. Nylon, or polyamide, provides good wear resistance and can be reinforced with glass fiber for additional strength.
Gelecta works with a broad range of materials, from clear plastics that comply with the applicable FDA requirements of the intended application to engineering polymers and the metal powders used in MIM production. Material compliance is always evaluated against the specific requirements and intended use of the component.
Sustainability is becoming an increasingly important consideration in injection molding. Although the process already offers relatively low material waste and efficient production at scale, manufacturers are reducing their environmental impact further through energy-efficient technologies. These include all-electric and hybrid injection molding machines as well as the use of recycled or bio-based materials. Such measures reduce reliance on virgin fossil-based raw materials and can also lower costs over the long term.
Gelecta’s injection molding expertise
Gelecta is a Finnish sourcing and project partner specializing in the production of technical plastic and metal components through an international manufacturing network. With more than 1,000 injection and compression molds delivered and over 25 years of international experience, Gelecta provides comprehensive support for injection molding projects.
The service offering covers prototypes, pre-series production, mold design and manufacturing carried out by Gelecta’s manufacturing partners, serial production, final assembly and packaging.
One of Gelecta’s key strengths is its integrated supply chain. The company maintains an audited manufacturing partner network in Asia, particularly in the Shenzhen, Dongguan and Guangzhou regions. Partner factories hold at least ISO 9001 certification, supported by Gelecta’s own regular supplier audits in China.
A local Sourcing Manager coordinates supplier cooperation and follows up quality at the manufacturing partners’ facilities. This enables direct communication, rapid response and close project coordination.
European customers benefit from cost-efficient international manufacturing while agreed technical specifications and quality targets remain under control. Gelecta’s Finnish office is located in Lahti, and the local Sourcing Manager in China supports projects both remotely and directly at partner factories. This enables close communication between the customer, Gelecta and the manufacturing partner throughout the project.
Gelecta’s manufacturing partners design and manufacture injection molds as well as molds for die casting and MIM applications.
To accelerate development, projects can also use rapid tooling solutions and different prototyping methods. Vacuum casting in silicone molds can produce sales-quality plastic components with lead times starting from approximately two weeks, depending on project complexity.
Small and medium production runs, ranging from a few hundred to tens of thousands of components, can also be manufactured using cost-efficient steel molds that provide a lighter alternative to full-scale high-volume production tooling.
For example, vacuum casting in silicone molds allows customers to evaluate form, fit and surface finish before the final injection mold is completed.
Gelecta also provides digital project support tools. The Virtual Trial Application, or VTA, enables customers to monitor mold trials remotely through live video and production data. Customers can review initial sample components, provide feedback and request adjustments without travelling to the production facility.
Quality, certifications and industry trends
Injection-molded components are often used in critical applications, including the automotive and medical technology industries, where quality requirements are demanding.
Gelecta’s manufacturing partners hold at least ISO 9001 certification, and many also hold industry-specific certifications such as IATF 16949 or ISO 13485. Process transparency is an important part of Gelecta’s operating model, and customer factory visits and supplier audits can be arranged when required.
Many manufacturing partners also comply with additional product- and application-specific requirements, such as UL, RoHS and REACH.
The injection molding industry continues to develop through automation, digitalization and improved quality control. Modern production systems increasingly use process data, sensors and automated controls to improve repeatability, efficiency and traceability.
Gelecta’s Virtual Trial Application supports this development by enabling remote mold trial monitoring and faster decision-making during tooling projects.
Multi-material solutions, including overmolding and insert-molded structures, make it possible to add functionality by combining different materials within a single component.
Customization and visually demanding components are also becoming increasingly important, particularly in consumer products. High-quality surfaces, controlled colors and appearance-critical features must therefore be considered throughout product design, tooling and production.
Partnering with Gelecta
Injection molding remains one of the most important methods for serial production of plastic components. A similar shaping principle is also used in metal injection molding, or MIM. When implemented correctly, these processes provide high quality, competitive unit costs and efficient production.
By combining manufacturing expertise with a strong international partner network, Gelecta provides companies in the Nordic countries, the Baltic region, Germany, Poland and other markets with a reliable solution for sourcing technical components.
Gelecta’s end-to-end project model, from manufacturability analysis and prototyping to mold trials and serial production, helps optimize both component manufacturability and supply chain efficiency.
Gelecta can support material selection, component geometry and the selection of the most suitable manufacturing method, whether the project requires plastic injection molding, MIM or an alternative production technology.
During production, local sourcing coordination and quality follow-up help keep the project aligned with the agreed schedule, specifications and quality requirements.
Contact Gelecta to discuss your project requirements, from prototype batches to full-scale serial production, and learn how Gelecta’s digital tools and global manufacturing network can support a smooth and cost-efficient project.