How 3D printing complements injection molding
Though 3D printing and injection molding are just two manufacturing methods and processes from two different eras, they're both used to manufacture plastic and electronic components. Despite this, there are some key differences between them, with each process having its own unique capabilities and benefits.
However, the most innovative manufacturers have also discovered that 3D printing and injection molding can be used to complement each other and bring greater advantages to customers.
- What is 3D printing and injection molding?
- What are the benefits of 3D printing?
- What are the benefits of injection molding?
- What are the differences between injection molding vs 3D printing?
- How can 3D printing and injection molding work together?
- How is Essentra Components using 3D printing and injection molding?
What is 3D printing and injection molding?
Injection molding and 3D printing use very different equipment and manufacturing processes. This means they create components with particular qualities suitable for many industries including electronics, automotive, EV, etc.
The injection molding manufacturing process uses both heat and pressure to mass-produce components from thermoplastic or metal. These materials are heated until they are molten before being injected at high pressure into a mold.
This pressure helps the molten material to form the part as it cools before it is ejected from the mold. The component may then undergo finishing processes, such as polishing, coloring or the removal of excess material, to create the final part.
In contrast, 3D printing (also known as additive manufacturing) is a manufacturing process that uses a combination of design software and a specialist printer to create components. There are many paid and open-source software programmes that designers use to design and create their products before sending them to print.
The printer then uses the inserted material (usually plastic but also metal) to build individual products layer by layer. Once the 3D printing process begins, it can take between a few minutes and several hundred hours to create components depending on their size, complexity and composite materials.
What are the benefits of 3D printing?
The benefits of 3D printing technology lie in its speed, flexibility and ability to create complex and intricate designs. As such, the invention of 3D printing opened up a huge range of new capabilities and advantages for designers and manufacturers.
Rapid prototyping
The ability to print plastic parts, including those with complex designs, directly from software means fewer processes are required to translate a CAD into the final product.
In some cases, it's possible to test a prototype idea directly within the software before printing it. This enables more rapid iterations of product designs and means physical properties and characteristics can be checked before starting high-volume production.
As a result, the prototyping process of testing, iterating to correct mistakes and gathering feedback can be completed very quickly, enabling a faster time to market. Though it is worth noting that the additive manufacturing process builds each product layer by layer, so prototyping a product may still take some time.
Cost efficiency in certain cases
If a customer is looking to create a one-off product or an exclusive range or collection, then 3D printing complex parts is a great way of manufacturing them cost-effectively. Indeed, for the low-volume production of plastic components, particularly for relatively small plastic parts such as caps and plugs, 3D printing is the most cost-effective option of the two technologies.
Compared to the equipment and tooling required for injection molding, additive manufacturing has a relatively low entry cost. This cost-effectiveness is also increased by the quicker lead times and reduced energy requirements of 3D printing compared to injection molding.
3D printing can also be used to create prototypes and molds for injection molded parts more quickly and at a lower cost than traditional methods, such as machining or electrical discharge machining (EDM). This can result in cost savings for the injection molding manufacturer, which can be passed on to the customer with lower prices.
Greater customization, accuracy and quality
The layer-by-layer creation process means 3D printing can be easily adjusted and changed, even with a pause mid-process. This means a high level of detail and accuracy can be achieved.
3D printing also allows for greater product customization. By creating custom inserts for injection molds, manufacturers can create products with unique features or textures. Examples include coarse noise textures that add grip to handles and threads on screws.
Yet it is important to note that the layering method of additive manufacturing does mean it’s difficult to create larger products or achieve a smooth surface finish on the final component.
What are the benefits of injection molding?
Injection molding is a traditional manufacturing method that’s been used for more than a century and is still the process of choice for component mass production. Plus, the greater energy efficiency and accuracy of modern electric injection molding machines mean manufacturers and their customers can enjoy even more benefits.
High-quality products
By tightly controlling the heat and pressure used in the injection molding process, experienced manufacturers can create high-quality products. The ability to use mold tools of different shapes, sizes and levels of detail can be created using the injection molding method.
Plus, a variety of thermoplastics are available including low-density polyethylene (LDPE) and polypropylene (PP) meaning injection molded components can have a range of qualities and characteristics. As a result, customers will be sure to find a high-quality component that has the physical and material properties they need.
Cost efficiency at scale
Injection molding has long been used to create huge amounts of products quickly. Designed for high-volume production runs, once the process’s parameters have been set and the mold tool is chosen, an injection molding machine can create thousands of products every hour.
So even though the initial investment in injection molding equipment is significant, the return is quickly realised thanks to its ability to create large amounts of products at once. Some molds are also designed with multiple cavities to increase the efficiency of production and cost even further.
Greater design variety
Unlike 3D printing (which until recently, could only print with plastic), injection molding has long been a manufacturing technique used to create products in both metal and plastic. The ability to adjust the heat and pressure of the process also means a range of materials can be used depending on the specific qualities and design required.
What are the differences between injection molding vs 3D printing?
The differences between injection molding vs 3D printing stem from the fundamental elements of each process including equipment, material use and design flexibility. This means they produce components in different quantities, with various quality and price levels.
Quantity
Injection molding is a process that's designed for producing components at scale. Able to create multiple components at once due to the cavities in the mold tool. Injection molded parts can also be produced quickly thanks to the high heat and pressure used to mold the material.
In contrast, 3D printing can only produce one component at a time layer by layer. This means it's only efficient at producing small batches of components.
Comparison of the two technologies at a glance
| 3D Printing | Injection Molding | |
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| Cons |
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As 3D printing produces items via a layering method, it cannot produce the same smooth surface finishes possible with manufacturing methods such as injection molding. This layering method of production also leaves products with directional stress weaknesses that their injection molded counterparts don't have.
The design of 3D printed products is usually restricted by the imagination of the designer and the restrictions of the software being used. Whereas the variety of molding tools and thermoplastics available means injection molding can mass-produce components with a range of qualities and characteristics. Plus injection molding manufacturers can balance these parameters to create high-quality parts at scale.
Price
The price of both 3D printed and injection molded components depends on the number of parts that are produced. Injection molding is cost-effective when components are being produced at scale due to the initial costs of creating a steel or aluminum mold. In contrast, 3D printing is more affordable for small-batch production due to the lower initial investment.
How can 3D printing and injection molding work together?
Though manufacturers may choose to use either 3D printing or injection molding depending on the specific requirements of a product or customer, the two processes can be used together to great advantage. This is particularly the case when building new products, creating injection mold tooling or producing small batches of products for testing.
By prototyping a new product using 3D printing, manufacturers and their customers can test, review and iterate designs quickly and easily. This means products can be refined until they’re of the highest possible quality and functionality before investing in an expensive metal injection molding tool that cannot be adjusted.
Plus, master patterns and mold inserts can be used to 3D print an injection molding tool. Mold inserts can be used to add specific features to a part, such as a logo or texture, or to create complex geometries with more intricate features. These methods can be faster and less expensive than traditional mold-making methods, such as machining or EDM.
However, these mold inserts often have a very short lifespan as they are made from softer materials than normal injection mold tooling, such as plastic rather than steel. This means creating molds using 3D printing isn’t currently the most common production method. Though it does enable a higher degree of flexibility and cost-effectiveness, meaning it may become more popular in the future.
The agility and cost-efficiency of 3D printing mean it’s also a great way of creating small batches of new products to test with customers. As a result, businesses don’t need to make a large investment in the metal mold before knowing the product will make its required margin or profit. It also enables them to take customer feedback and adjust the final design appropriately without incurring huge costs.
In short, by combining the two processes of 3D printing and injection molding, manufacturers can make the mass production of products or components more accurate, cost-effective and agile.
How is Essentra Components using 3D printing and injection molding?
As an expert injection molding manufacturer, Essentra Components uses this process to mass-produce thousands of components every day. Having over 65 years of experience in using injection molding means the Essentra Components team understand how to combine the right mold and process parameters to create high-quality products at scale.
Plus, 3D printing plays a part in the development of new and custom products. As Technical Solutions Manager at Essentra Components, Neil Williamson explains, "Currently, 3D printing is mainly used to make samples of new parts at the product development stage before going to the expense of making an injection molding tool. However, it can also be used as an alternative to injection molding when only low quantities of a product are required."
Using 3D printing for low-volume production means customers don't have to invest in expensive tooling and experience long lead times. For custom or small-batch products, this means 3D prototyping can be used to quickly check that the final component is meeting the needs of Essentra Component's customers before injection molding production begins.
In short, by combining 3D printing and injection molding processes together and providing a hassle-free service, Essentra Components makes it easier for customers to get the highest quality products at scale.