Exploring Low-Pressure Injection Molding: Efficiency and Versatility

Table of Contents

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low pressure injection molding
Source: https://www.youtube.com/watch?v=LXydS-4ovBI

As a manufacturer already accustomed to high-pressure injection molding, there is no doubt that you’ll be elated to hear of a better plastic injection method with similar or even better high quality results. That’s the feeling low-pressure injection molding gives you considering that it allows molten plastics flow gracefully without intense pressure yet results in beautifully molded parts. 

The efficiency, cost savings, and flexibility are some of the benefits that attract injection molding manufacturers to low pressure injection molding. This guide gives you all the low down with low pressure injection molding.

Let’s not waste any more time, let’s dive right into it.

1. Understanding Low-Pressure Injection Molding

1.1 Overview of Low-Pressure Molding Process

Typically, manufacturers of injection molded components are used to the high-pressure method of part production. However, innovative methods often cause some stirs in the injection molding world. One such technique is low-pressure injection molding. 

With conventional injection molding methods, materials are forced into mold cavities at enormous pressures. 

But with low-pressure as its name implies, the passage of materials into mold cavities is at reduced pressures and that’s why manufacturers just love this. 

The most charming part of low-pressure injection molding is its efficiency assisted by its consistent nature to shorten cycle times without sacrificing quality. 

And that’s not all, energy consumed is immensely reduced while being cost-effective in one breath. Not to mention the excellent finish of the final component produced. 

1.2 Key Components and Equipment

As magical as low-pressure injection molding is, there are major components and equipment that make this magic happen. 

At the center of this magnificent technique are the tools and equipment that low-pressure injection molding significantly relies on, chief among which is the low-pressure machine. This special machine is responsible for the low-pressure injection of molten materials into the mold where the product is molded. 

In addition to the low-pressure machine is the uncommon mold that is crafted to suit the low-pressure flow of the injected material. 

These mold cavities ensure coherence in the molded part with no room for twisting. And of course, your material is a key player in low-pressure injection molding. It must be meticulously chosen to align with the designed low-pressure flow and the specified quality.

2. Advantages of Low-Pressure Injection Molding

2.1 Reduced Material Stress and Warpage

One fascinating benefit of low-pressure injection molding is the solution it provides against imperfections and deformities caused by material stress. 

How is this attainable you might wonder? 

If you are familiar with injection molding methods, you’ll remember that a major drawback of high-intensity injection molding is its vulnerability to deformity due to its pressure. On the flip side, low-pressure injection molding eradicates that challenge as a result of a gentle yet effective approach to manufacturing parts. 

When molten materials are injected into the mold cavity at lower pressure, what you’ll get is a stable, well-formed, and mechanically sound component ready to perform its functions seamlessly and efficiently. 

It doesn’t end there. 

The controlled flow after reducing material stress and distortion makes the possibility of manufacturing intricate designs and complex geometric parts less of an illusion. A certain level of confidence and poise is evident in a manufacturer’s attitude because now they understand what to do and how to use sensitive materials that require gentle maneuvering. 

In addition, thin-walled components that are reputable for deformities in high-pressure injection molding are known to come out unmarked employing low-pressure injection molding, hence its selection as a top choice method of manufacturing complex-designed parts. 

2.2 Enhanced Design Flexibility

For a manufacturing method that gives other techniques a run for their money, you can be quite sure that numerous benefits are attached. Having considered the first advantage low-pressure molding offers which is reduced material stress and warping, a bonus to this method is the improved design flexibility. 

Low-pressure molding is capable of bringing dreams of ideas to fruition, ideas that conventional methods can only keep dreaming of without the capacity to bring them to reality. 

Similar to innovative manufacturing methods like 3D printing technology, low-pressure injection molding provides the grounds for manufacturers to spread their innovative manufacturing wings and soar. It helps them to create near-impossible designs.

That’s not all, the inclusion of strain relief qualities which incorporates components that are multi-functional in place of creating additional components that may likewise require extra steps. This technique is aimed at simplifying the manufacturing process with an all-inclusive approach to designs. 

On top of that, the product gains more reliability and durability with awesome reviews from its users. Interestingly, low-pressure injection molding highly supports the manufacturing of overmolded components which requires the layering of different materials until the desired component is achieved. 

The only hindrance to low-pressure molding and design flexibility is imagination.

2.3 Cost Efficiency and Sustainability

Do we need to say more? But that’s not a problem. In addition, the benefits of low-pressure molding are its cost efficiency and sustainability. Low-pressure injection molding is the ability to save the cost of manufacturing and the environment. 

With a consciousness of our failing environmental attributes, low-pressure injection molding intends to save the planet by waste reduction. Low-pressure injection molding is also very budget-friendly due to the lower consumption of energy that results from the reduced cycle time in manufacturing. 

The gentle and controlled injection of materials already saves you from material wastage, but that’s not the only contributor to sustainability. 

Sustainability is attained in low-pressure injection molding by the less energy consumed and the less materials used which in turn saves wastage.  Manufacturers are identifying ways of eliminating environmental footprints that negatively affect the planet. However, with low-pressure injection molding everyone wins. 

Manufacturers get to save cost and waste less material while achieving the intended result, and mother earth gets to be saved by consuming less energy and leaving little to no harmful environmental footprints. And the world together is happy once again.

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Low pressure injection molding for electrical cables 
Source: https://www.youtube.com/watch?v=xLP5IR1ocdE

3. Applications of Low-Pressure Injection Molding

3.1 Electronics and Electrical Industry

The usefulness of low-pressure injection molding in manufacturing industrial components is boundless with most manufacturers employing this method in producing parts for numerous industries. One such industry is the electronics and electrical industry. 

In this industry enclosures and protective parts are important in safeguarding delicate parts. Low-pressure injection molding is a sure method to manufacture these parts. Electronic parts such as sensors, circuit boards, and connectors to mention a few have benefitted immensely from deploying low-pressure injection molding in producing them.

Additionally, in a bid to ensure longevity in electrical components, low-pressure injection molding has always delivered the goods in protective shields for such fragile electrical parts. Also, low-pressure injection molding due to its nature is suited to manufacturing parts capable of withstanding the elements, ensuring vibrations, moisture, and dust-free components thrive in their respective functions. 

Irrespective of the complexity of the designs of these components, low-pressure injection molding is up to the task. It is cost-efficient, durable, and maintains excellent mechanical integrity in all electrical and electronic parts produced.

3.2 Automotive Industry

In the automotive industry, manufacturers typically make specific parameters a priority. Precision is often top of these considerations and no wonder they often opt for manufacturing methods line high-quality CNC Machining. Other factors include resilience in withstanding rough road conditions, durability for long-lasting components, and aesthetics for the eye-catching effect. 

For that reason, low-pressure injection molding is the best fit to achieve all automotive parts goals. 

It’s not surprising to see it take the wheel in such a regard. Automotive parts such as encased connectors and sensors, interior fittings, crafted grommets, and cable harnesses are responsible for its water-resistant characteristics amongst other properties. 

With low-pressure injection molding in the automobile industry, there are no limits to what is achievable, either electric automobiles or fossil-powered engines. Components manufactured for automobile assembly are deeply concerned about performance and safety. So, whatever your preferences, they are never an issue. 

The introduction of low-pressure injection molding is driving innovation and making dreams come true in designing parts that may seem unlikely to traditional methods. It is deeply assuring for manufacturers to be confident of compact wiring and secure-fit components under the hood with a streamlined process of manufacturing essential to saving costs. 

3.3 Medical and Healthcare Sector

Medical practitioners and regulators in the medical and healthcare sector hold certain prerequisites in high esteem. Medical tools are hugely bothered by the biocompatibility of medical instruments which determines its effects on contact with the human body. 

So, it is no wonder stringent quality control measures are set in place to check manufacturers and their products. Furthermore, precision in the dimensions and complex geometries of the component, and sterility of the medical device manufactured. 

These are requirements that must be fulfilled to certify the accurate, sterile, and safe usage of medical instruments. 

Nonetheless, low-pressure injection molding covers all of these non-negotiable factors. From delicate medical tools to disposable medical parts, low-pressure injection molding delivers on all fronts. Its ability to attain high standards of sterilization differentiates low-pressure injection molding apart from the rest. 

With the continuous demand for medical tools such as surgical instruments and various patient-centric devices, low-pressure molding is a reliable and precise method of manufacturing parts that can be trusted for quality medical and healthcare components. 

The diverse industries, including the high-quality mold manufacturing industry have felt the presence of low-pressure injection molding. This may be connected to its unconventional and versatile method that combines precision, protection, and innovation. One more thing is necessary for a complete and successful low-pressure injection molding process.

4. Process Considerations and Challenges

4.1 Material Selection and Compatibility

The final part of this enlightening journey comes to a crescendo with an essential part of any production which may have a massive impact on the final product manufactured. Having been convinced of the numerous benefits of low-pressure injection molding, material selection, and compatibility are a crucial success determinant of the process. 

The achievement of excellent low-pressure injection molding is hinged on the cohesiveness, compatibility, and curing time of the material in use. The process itself already offers seamless employability; meanwhile, the material has to align with the process. 

Moreso, in achieving this massive feat, intense material testing and validation can ensure that the selected material is the right fit for the desired component to be produced. The right material enjoys the conditions of low-pressure injection molding, unlocking its versatility and corresponding benefits of the process. 

Material selection and compatibility permit proper flow and outstanding mold filling for the manufacturing of mechanically sound and optimally functional components. 

Be that as it may, consulting material suppliers and conducting in-house testing by professional material engineers can guide you in making a good choice of selected material. 

4.2 Mold Design and Venting

Similar to most injection molding methods, mold design, and venting systems are essential in forming the best components for high-quality mold manufacturing. This is a function of particular considerations given to parts of the injection molding machine such as the gate design, parting line placements, and venting systems. 

These parts of the machine control the filling and cooling of the materials while forming the desired component progresses. With proper mold designs, the gate design ensures an excellent flow rate, and the fill balance is evenly spread especially with the lower-pressure method of filling. 

Mold designs are crucial to understanding the effect of elements such as air entrapment and flash formations, and how it can jeopardize the part’s quality. 

Another factor to be considered that fosters efficient low-pressure injection molding is the venting system inducted into the mold. We mentioned air entrapment earlier, but with an effective venting air trapped in the mold can be released during the process, ensuring that there is no room for flaws. 

The inadequacy of venting features impairs the quality of parts resulting from air entrapment. When designing the mold, the accurate placement of the vents encourages the manufacturing of components that meet the highest standards. 


In a nutshell, exploring the intricacies of low-pressure injection molding has been phenomenal for the manufacturing of tools and parts across various industries. The application of low-pressure injection molding has set a new standard for achieving high precision with top quality at a reduced cost and minimized material waste. 

This leads to its cost-efficiency while being environmentally friendly. On top of that, there are numerous benefits attached to low-pressure injection molding. Some of these are design flexibility that assists designers to breathe life into their ideas and innovations. Reduction of warping and material stress is a major benefit as well. 

To fully unlock the many attributes and features of the process, factors like material selection and compatibility; and mold design and venting are crucial to enjoying a seamless operation of low-pressure injection molding with optimal molding outcomes. We hope this serves as an interesting insight into the world of low pressure injection molding. 


Gary Liao

Gary Liao

Gary Liao is the Engineering Manager of TDL Company and has more than 20 years of mold design experience.

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