Injection molding is the process of choice where parts are to be manufactured with complex or simple shapes in a repeatable and cost effective manner. This could be in large volumes or low volumes. Traditionally, this process involves melting thermoplastic materials at high temperatures and injecting them into molds under relatively high pressure to create parts with precise shapes and dimensions. More modern injection molding processes have expanded the definition of injection molding beyond this. Injection molding processes today implement advanced technologies that allows manufacturers to meet the demand for more delicate, energy-efficient, and sustainable manufacturing methods. This has led to the development of diverse injection molding processes and amongst these are low temperature injection molding processes.
Within the concept of this article low temperature injection molding refers to various specialized injection molding processes that operate at significantly lower processing temperatures than the conventional thermoplastic injection molding processes. This is particularly valuable for manufacturing components that contain heat-sensitive materials, electronic assemblies, delicate substrates, and specialized polymers. Operating at lower temperature can achieve lower energy consumption, improved material properties, improved safety and environmental friendliness and in some cases expand injection molding process to products that would have initially not been processible by injection molding due to temperature restrictions..
Low temperature injection molding processes are used to manufacture products that find applications in industries such as electronics, medical devices, automotive manufacturing, and consumer goods. This article explores some low temperature injection molding processes. It explores the principles, advantages, applications, challenges, and future prospects of these low temperature injection molding processes. So if you’re looking for a manufacturing process that would not exert so much thermal stress on your material, this article is for you.
The Concept of Low Temperature Injection Molding Processes
While traditional injection molding may require processing temperatures ranging between 200°C and 350°C, depending on the type of material, low temperature injection molding processes are those that can be run at much lower temperatures, typically between 80°C and 180°C. The exact temperature used for each process depends on the type of material being used and the requirements of the application.
In general, the processes involve the same stages as standard injection molding from feeding of the materials into the barrel to heating and melting to injection, solidification, cooling and ejection of part. Except all of these happen at lower temperatures by strategic selection of materials and process parameters.
Low Temperature Injection Molding Processes
The following are specialized injection molding processes that can be carried out at relatively low temperatures compared to conventional injection molding. Note here that low temperature injection molding is not being referred to as one specific process but a selection of processes, based primarily on the temperature at which the injection molding can occur successfully.
Low Pressure Powder Injection Molding
This process is used to produce metallic parts using low molecular weight polymer based binders. The metal is introduced in the powdered form. The processing temperatures can be as low as 90oC. The injection and molding process is followed by debinding and sintering processes that remove the binders and fuses the metal compounds together. This process has the advantage of achieving metal-like parts at low temperatures using an injection molding process that allows complex parts to be formed. The process can also be used to achieve micron sized parts.
Reaction Injection Molding Process (RIM)
RIM process involves the in situ polymerization of monomers within the injection molding process. It requires special tooling and/ specialized injection molding machine beyond the conventional injection molding machine. It is widely used for polyurethanes. For exothermic polymerization processes, only the activation energy needs to be provided since the reaction results in generation of heat. One key process consideration here is to ensure effective mixing of the monomers and select optimum mold temperatures as mold temperatures can significantly affect properties such as young modulus of the final part.
Low Temperature Overmolding
This process involves injection molding of polymer melt over a previously injected polymer in the mold within the same molding cycle. This achieves a part with two components partly fused together. Low melting polymers such as TPU and hot melt polyamide adhesives can be used in low temperature overmolding.
Silicone Rubber Injection Molding
Liquid silicone rubber is typically molded between 90 and 120 degrees celcius to achieve fast curing. If even lower temperature is required, room temperature vulcanized (RTV) grades can be used to achieve curing at room temperatures. This however takes longer time and the long cycle time must be really justified to make this sustainable. This can be used in overmolding silicone onto inserts or onto other polymers.
Materials Used in Low Temperature Injection Molding
The low temperature injection molding processes are not applicable to the same wide range of materials that can be processed using standard injection molding processes. Each type of process discussed in the following section is applicable to specific types of material as explained within each section. In general these are materials with low melting points and low melt viscosity and enhanced flow characteristics.
Polyamide-Based Hot Melt Adhesives
These materials are widely used for encapsulating electronic components. They offer excellent adhesion, moisture resistance, and flexibility while processing at relatively low temperatures. They are used in overmolding and as binders in low pressure powder injection molding processes.
Thermoplastic Elastomers (TPE)
TPE materials combine the flexibility of rubber with the melt processing advantages of plastics. They vary from low melting to high melting grades. Therefore when selecting TPE for low temperature injection molding, ensure you specifically select the low melting grades. They are very common in overmolding..
Ethylene Vinyl Acetate (EVA)
EVA is also common in overmolding, it is known for its softness, flexibility, and low melting temperature. It is commonly used in protective covers, cushioning products, and medical applications.
Polyolefin Compounds
Although the standard polyolefin processing requires the conventional injection molding process. Certain polyolefin like LDPE materials can be processed at reduced temperatures while maintaining good mechanical properties. For example LDPE can be used in binder formulation alongside other components such as plasticizers to significantly reduce the melt temperature and viscosity of the binder formulation in low pressure powder injection molding process.
Specialty Low-Melt Polymers
These refer to proprietary compounds specifically formulated for low temperature molding processes. These materials offer enhanced performance and processibility in applications where thermal sensitivity must be considered. ExxonMobil for example offers a range of specialty polymers for low temperature processes.
Advantages of Low Temperature Injection Molding
The key advantages of low temperature injection molding processes lies in material protection, energy saving, improved material properties and more. We elaborate on this in the following sections.
Protection of Heat-Sensitive Product Components
With low temperature processing delicate electronic components can be encapsulated without causing thermal damage to them. Such components include printed circuit boards, sensors, connectors, and microelectronic assemblies that would otherwise get damaged if exposed to higher temperatures of conventional injection molding processes.
Lower Energy Consumption
If you recall the enthalpy equation, heat energy consumption is proportional to temperature change. Therefore operating the injection molding process at much lower temperature means reduced energy consumption. This reduces the running cost. Furthermore, as manufacturers face more pressure to reduce their environmental footprint and adopt more energy-efficient manufacturing methods, low temperature injection molding processes become increasingly attractive.
Faster Production Cycles
Lower temperatures typically means it takes less time to reach set temperatures and it also takes less time to remove the heat during cooling. This consequently results in shorter cycle times and higher production efficiency.
Material Options
Some materials are avoided in the conventional injection molding process due to the high temperatures potentially causing damage under traditional molding temperatures. This limitation can be removed at lower processing temperatures. This expands process and product design possibilities and could improve efficiency.
Reduced Thermal Stress
High temperatures can introduce internal stresses within molded parts. This potentially results in defects such as loss of dimensional stability, burns, warping. It may also impede long-term product performance. Adopting low temperature injection molding processes where possible can temperatures help minimize these issues.
Reduced Burn Related Risks
While safety measures should not be relaxed even in low temperature injection molding, lower operating temperatures reduce the risk or severity of burns and heat-related accidents in manufacturing environments. Thus contributing to a safer workplace.
Challenges and Limitations
Despite its advantages, below are some of the limitations of low temperature injection molding processes.
Limited Material Options
The general principle of injection molding requires material being processed to flow into the mold and solidify before being ejected. Conventional injection molding achieves this through heating the material just around its melting point. The efficiency of the process depends in good part on the temperature viscosity relationship of the material. The range of materials that can meet the flow requirement at low temperature processing is much less than that for conventional injection molding. This may restrict design flexibility in some projects.
Mechanical Property Constraints
Certain low-melt materials may not provide the same strength, stiffness, or heat resistance as high-performance engineering plastics. This therefore limits the mechanical properties attainable in products manufactured using low temperature injection molding processes. Manufacturers must therefore carefully evaluate whether the process meets the intended application requirements.
Equipment Requirements
Some low temperature injection molding processes require specialized molding machines or tooling optimized for the particular type of low-temperature processing. This may incur additional cost.
Cost of Specialty Materials
Advanced low-temperature compounds can be more expensive than traditional molding materials. On the other hand, these costs may be offset by energy savings and possibly higher mark off price of the products. Nonetheless, this should be taken into account.
Design Limitations
Since low temperature injection molding processes tend to have a more limiting materials library, production of complex geometries or applications requiring extreme mechanical performance, these methods may not be suitable and conventional injection molding may still be better options for such.
Applications Across Industries
Low temperature injection molding processes have found applications across diverse industries from electronics to medical to consumer goods amongst others.
Electronics Industry
One of the industries where low temperature injection molding processes find application is in the electronics industry. Processes like overmolding and rubber injection molding are used to encapsulate and mold electronics components in products such as:
Sensors
Connectors
Printed circuit boards
Cable assemblies
RFID tags
Microelectronic devices
In these applications the low temperature injection molding often involves the goal of forming a protective barrier against moisture, dust, vibration, and mechanical damage.
Medical Devices and equipments
Medical equipment and devices often contain delicate electronic components and heat-sensitive materials that would otherwise get damaged at elevated temperatures.. Medical parts produced using low temperature injection molding processes include:
Wearable medical sensors
Diagnostic equipment
Catheter components
Surgical instrument handles
Medical connectors
Automotive Industry
While the early automotive industry made use of mostly mechanical parts, modern vehicles contain numerous electronic modules, sensors and systems that require more delicate manufacturing processes. Low temperature injection molding processes are applied in production of:
Wire harness protection
Sensor encapsulation
Battery management systems
Electronic control modules
Lighting assemblies
Consumer Electronics
Today consumer electronics perform increasingly complex functions and are becoming more integrated in everyday life. Many of these products are also required to be more portable, rugged and be aesthetically appealing. From smartphones, smart watches, to smart home refrigerators, and earpods, low temperature injection molding processes enable compact designs while safeguarding internal electronics from external influences.
Industrial Equipment
As the industry 4.0 sees more automation in industrial processes, these increasingly sophisticated systems rely heavily on sensors and electronic controls. These often employ low temperature injection molding proccesses to achieve robust protection against moisture, chemicals, dust, and mechanical impacts.
Future Percepectives
Materials science is likely to see continued advancement in the future. Particularly with the use of advanced chemistry tools and open source AI tools for development of more complex materials that can meet the required specification for low temperature injection molding. We can expect to see new materials that can be processed at lower temperatures. This will be in part driven by the pressure on the plastic industry to adopt more sustainable processes and reduce its environmental footprint.
The reduced energy consumption and lower carbon emissions is likely to attract more product manufacturers to adopt these low temperature injection molding processes. This could push future investment in research towards developing more advanced material to support these processes and to further advance the processes to accomodate already existing materials.
As bioplastics gain increasing share of the market (albeit currently still a very small fraction (less that 1%), low temperature processes that can protect the mostly heat sensitive biomaterials becomes more important to manufacture wider range of products from biodegradable plastics. Finally as the industry attempts to shift away from plastics, low temperature injection molding processes such as low temperature powder injection molding process can be promising as they allow manufacturers to divert already purchased machinery into producing materials other than conventional plastics.
Conclusion
Low temperature injection molding presents the option of achieving injection molded parts with reduced heat input. Here it is presented as a number of injection molding technologies that canbe carried out at lower temperatures. These methods provide practical solutions for protecting heat-sensitive components while improving energy efficiency and to some extent provide some production flexibility.
Its applications span a wide range of industries. These include electronics, medical devices, automotive systems, consumer products, and industrial equipment. The advantages such processe offer includs reduced thermal stress on the material and machine parts and tooling, as well as lower energy consumption..
These processes are still challenged by limtations in the range of materials that canbe processed using these techniques amongst other limitations as discussed within the article. Nonetheless future advancements in polymer science and manufacturing technologies as well as shifting of priorities towards more environmentally sustainable processes promise to expand the capabilities of low temperature injection molding.
By Ololade Olatunji
June 12, 2026