Embracing Sustainability in Injection Molding

Table of Contents

Ice cube trays from sustainable material
Ice cube trays from sustainable material


While the cry for more sustainable manufacturing practices grows so loudly by the day, the onus on manufacturing to adopt innovative ways and materials to support this cause remains ever inevitable. Embracing sustainability is even more pressing on plastic injection manufacturers as they have applications across several industries where their influence is significant. 

However, there is immense potential in the injection molding process for sustainability given the emergence of several innovations like 3D printing, design for manufacturability, and simulation software. All these innovations show promises that injection molding can be pivotal for manufacturing sustainability. 

For this reason, we will be shedding more light in this article on the injection molding industry and its efforts into a more sustainable manufacturing process. So, without further delay, let’s dive in.

I. Sustainable Practices in Injection Molding:

Automotive application of aluminum injection molds
Automotive application of recycled injection molds

Innovative manufacturing practices have become one of the important components of the manufacturing industry even as the world shifts its focus to sustainable production. Technologies that reduce wastage, pollution, and the carbon footprints across industries are presently also making waves within the injection molding industry. 

One of these is recycled plastic which deals with the reuse of plastic waste in injection molding. Essentially, recycled plastic comes with many benefits while having numerous applications in different industries.

Take the automotive industry for example, recycled plastics find applications for various components including door panels, bumpers, dashboards, and fenders. It can also be used for both interior and exterior components. Consequently, automakers can benefit immensely from using recycled plastics especially in cost savings while achieving their sustainability objectives.  

Again, in the packaging industry, there is increasing demand for sustainable packaging unconventional methods like recycled plastics. While products like cosmetics and even food are packaged with environmentally friendly materials, manufacturers reduce their dependence on virgin plastics.

Another industry benefiting from the injection molding adoption of recycled plastic is the electronic sector where recycled plastics are used for manufacturing casings and enclosures for their products. While the durability of these products is not negatively affected by these recycled plastics, the plus is the reduction in the usage of virgin plastics while contributing to a cleaner environment.

However, all of these industries are a few among others like toys, furniture, and construction industries that have also embraced the sustainable injection molding use of recycled plastics. These industries can kill two birds with one stone using sustainable manufacturing technology to satisfy customers while reducing the negative impact of manufacturing on the environment.

Furthermore, acknowledging the contributions of injection molding technologies like gas-assisted, structural foam, and compression molding in sustainable manufacturing is in order. These injection molding techniques help reduce material and energy consumption during manufacturing further reducing carbon emissions and pollution in the environment.

In the end, recyclable plastics along with other biodegradable and bio-based materials are showing great promise of taking over virgin plastic usage as injection molding materials. This will help immensely in moving the manufacturing industry to the next stage of industrialization where the environment is greener and cleaner.

II. Custom Injection Molding Solutions for Niche Markets:

Custom Devices Plastic Injection Molding
Custom Devices Plastic Injection Molding

Custom injection molding produces precise parts for various industries, including military, medical, and automotive. Especially where low-volume injection molding is required, custom injection molding often emerges as the required solution.

However, to meet the peculiar needs of individual clients, US injection molding companies are adopting innovative ways to meet their clients’ needs across industries.

For instance, the use of 3D printing is one innovative method adopted by injection molding companies in the US to rapidly provide prototypes. These prototypes ensure that engineers can quickly analyze the effectiveness and functionality of the custom part before setting up for mass production. 3D printing is especially useful in the medical industry where medical trays have very stringent requirements both for dimensions and bio-compatibility.

Another innovative solution by US companies is the use of bio-composites such as fiber and plastics in the aerospace and automotive industry. These materials are used in creating custom parts that actively help to solve the challenge of lighter yet durable and strong materials to solve the challenge of fuel efficiency. These materials also help reduce fuel consumption which in turn lowers the carbon footprints of the products from these industries.

The use of sensors in the customization process also helps US manufacturers collect data for analysis in real-time helping them to be more effective and precise on mold manufacturing. These also help in reducing waste and environmental pollution during production.

III. The Impact of Injection Molding on Healthcare and Medical Device Innovation:

Medical plastic injection molding
Medical plastic injection molding

The medical and healthcare industries are one of a kind especially in terms of opportunities for the injection molding industries. These sectors are one of the most demanding when it comes to custom devices and parts as well as the introduction of novel applications and materials.

Besides the tight tolerances required for medical devices, they are often required to meet institutional requirements such as biocompatibility, sterilization, and antimicrobial requirements. These requirements are the driving features for injection molding technologies in these fields.

For instance, in manufacturing prostheses for patients’ limbs and arms, injection molding manufacturers need to meet these requirements including functionality.  

Nevertheless, medical injection molding companies like Rocardioinvest are taking the challenge even further in the manufacture of a three-branched heart valve using customized polyamide material. While it was very tasking, the company molded these 0.25g weight devices using innovative techniques to ensure that the valves were free from blood clots and sediment formation by keeping the margin of error to zero.

Kobelin Formenbau is another company blazing the trail in medical tooling for creating devices like this heart valve. The objective is to ensure that there are no post production processes required.

Again, the application of injection molding technology especially in medical tools for minimally invasive surgery is taking roots in the medical industry as these devices and tools become tinier. It also means that the precision and intricacies required in their manufacture is increasing. Importantly, it is this micro-injection that is driving the advancements in the medical industry.

IV. From Concept to Reality: The Journey of a Product in Injection Molding:

Mold design using CAD2
Mold design using CAD2

From the conceptualization of a product in the mind of the client to the ejection of the product from the mold the journey of injection molded products follows a well-designed path leading to success.

Once the client is clear on the functionality and design of the product, the next step is usually to approach a reputable injection molding company to manufacture the product. However, the injection molding company begins with designing a mold that best suits the product while considering the manufacturability.

To begin the design, engineers often make use of CAD software and some mold flow or simulation software to ascertain the pattern of flow in the mold. Other tools in the mold production stage include the CNC machine to cut the mold to shape and size as well as the final texture of the product required. 

A great deal of expertise and experience is required on the part of the mold design engineer to come up with an excellent mold. Nevertheless, the mold material also plays a pivotal role in ensuring the success of the molded product. 

Thankfully, cost-effective technologies like 3D printing can rapidly provide a prototype of the mold to confirm its effectiveness. Once past this mold production stage the remaining steps become easier. The next steps are the injection molding process proper.

Clamping the mold is the first step in injection molding and it requires adequate force to secure the two halves of a mold in place. Then comes the heating and injection of the molten plastic into the mold where the injection fluid temperature in the mold becomes critical as too little or too much can lead to product defects.

Removing any air pockets in the mold is the next phase. This is achieved through the application of adequate pressure for uniform filling. The cooling stage follows where the molten liquid is left to solidify after which it is then ejected from the mold using features like ejector pins and design features like draft angle to enable easy ejection from the mold.

However, it should be noted that collaboration between the client and the manufacturer is of utmost importance since the client is the concept convener and the manufacturer has the skill to convert this concept into reality. Anything short of collaboration between these two entities can potentially lead to an unsuccessful injection molding project.

V. The Evolution of Injection Molding Technologies

3D Printing
3D Printing

The modern injection molding machine or even the injection molding process that you have today didn’t start out this way. 

It has evolved over decades and centuries to arrive at its present state. Starting from the 1870s with the first injection molding machine by John Wesley Hyatt to the 1970s when Hendry presented us a gas-assisted injection molding machine the journey remained progressive. 

It wasn’t until three decades after World War II that the production of plastic products significantly exceeded that of steel while aluminum molds became widely accepted in the 1990s.

Nevertheless, the injection molding industry is now a multi-billion-dollar industry with millions of tons of plastic products leaving the screw injection molding machine around the world each year. Also, the technology has evolved to several techniques including vacuum, compression, and blow molding all being used for specific purposes in different industries.

But, despite the advancement in computer-designed plastic parts and the increased precision in part manufacturing, the demand for plastic material alternatives is also growing.

Major players like the automotive and electronic industries which employ plastic materials like Polypropylene and ABS for weather and impact resistance respectively are increasingly finding alternatives to these materials.

However, advancement in injection molding continues to grow with more injection molding techniques like transfer injection molding, structural foam injection molding, and gas-assisted injection molding playing significant roles in the evolution of this technology from its inception till date.


In a nutshell, the injection molding industry has made significant strides in embracing sustainability in manufacturing especially in developing alternative materials for virgin plastics. Biodegradable, bio-based, and recyclable materials are some of the alternatives to plastics that have been adopted in injection molding.

Also, the advancement in technology which has brought methods like 3D printing and CAD software to the fore is enhancing the design process ensuring that it is more effective, precise, and waste-reducing.

Essentially, the injection molding industry has come a long way and has evolved to adopt some of the most sustainable manufacturing processes derived from the growing demand for customization and miniature devices. Ultimately, the innovation that keeps changing the landscape is sure to lead this industry to a more sustainable, energy-efficient, and cleaner environment. 


Gary Liao

Gary Liao

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

Contact Our Experts

Send us a Email, we will feedback to you ASAP!