Silicone injection molding and 3D printing are two excellent manufacturing methods with the same goal: creating a 3D product. However, these two processes are very different, each with its own set of advantages and use cases. The following compares silicone injection molding versus 3D printing. It is imperative that companies understand each of these processes in order to determine which method is best for their specific application. As you will see, in some cases, it may make sense to employ both 3D printing and silicone injection molding on a single project.

What are 3D Printing and Silicone Injection Molding?

Both 3D printing and silicone injection molding start with a digital 3D design but quickly divert down two very different manufacturing paths. 3D printing is a process that builds a three-dimensional object based on a Computer Aided Design (CAD) sketch. 3D printing is one of several technologies under the umbrella of Additive Manufacturing (AM), named as such since it starts from nothing and builds layer by layer of material. The 3D printing machine uses the CAD data to add successive layers of liquid, powder, or other material to manufacture a 3D object. A wide range of materials can be used for 3D printing including metals, plastics, and composites and these are called filament. The equipment required for 3D printing are the spools of filament material and the 3D printer itself, resulting in low upfront capital costs. 3D printing allows manufacturers to fabricate parts on-demand as this process only needs a new CAD input in order to manufacture a new product, and does not require retooling or machine changes. Lastly, 3D printing generates minimal waste since it is an AM method.

As for silicone injection molding, the process begins when silicone is fed into a heated barrel. A screw is used to mix, heat, and transport the silicone toward to the mold. The melted material is then injected through a nozzle into the mold and travels via a gate and runner system into the mold cavity. As the silicone enters the mold, excess air can be released via vents. The pressure and temperature of the mold are maintained to allow the silicone to conform to the desired shape and harden quickly. Once the part is adequately cooled, the mold opens and the part is ejected. The mold is then ready to receive the next charge of silicone. The key equipment necessary for silicone injection molding include the silicone and any additives, an injection molding machine, and the mold which is typically made of a hard metal. A commonly used material in injection molding is LSR, or liquid silicone rubber. Silicone injection molding is a very fast process that generates high-output production compared to other molding methods, making injection molding a more efficient and cost-effective solution. Silicone injection molding produces products that are virtually identical from part to part which provides excellent brand consistency and part reliability.

Is Silicone Injection Molding or 3D Printing Better?

The answer, of course, depends on the specifics of your project. Generally speaking, 3D printing and silicone injection molding do not compete for the same projects as they are each suited for different manufacturing situations. Below are some examples of when each process makes good business sense.

Injection molding is often best suited for production runs with medium to high volumes of an identical product – up to thousands and even millions of parts. Injection molding tooling is often a large expense; thus, larger production runs are necessary to offset the cost of tooling on a price per part basis. Once tooling is fabricated, injection molding is hard to beat in terms of time per part since products are often molded in minutes or even seconds. Injection molding is usually the method of choice for manufacturing parts that will move against other pieces as the surface finish is smooth. Lastly, silicone injection molding is a proven and trusted technology with decades of experience and know-how to rely on.

In general, 3D printing is most cost-effective for lower volume runs including prototypes and small batches. This technique offers customers flexibility and the ability to tweak the design by simply modifying the CAD inputs since no hard tooling changes are required. This method is also attractive when a quick turnround time is necessary as little lead time is necessary and custom tooling is not required.

There are some instances where a combination of 3D printing and silicone injection molding is most cost-effective. For example, 3D printing may be used for prototyping as well as “bridging” the gap between design and full production in order to get products to the market rapidly while the injection molding tooling is fabricated. Then, once the tooling is available, silicone injection molding is employed for full, high volume production.

ProMed’s Molding Capabilities

ProMed was founded in 1989 to address an industry need for cleanroom manufacturing of silicone components, specifically those having a medical application. We have garnered a reputation as the world benchmark of implantable silicone components and assemblies – and are one of few companies in the world to provide contract manufacturing of drug-eluting products.

ProMed has expertise in working with the full spectrum of silicones covering a wide range of properties and characteristics. We will assist in your material selection to help ensure all design requirements are met. Our manufacturing facilities and equipment are designed for a single purpose—to mold medical and implantable silicone, combination components, and bio-material grade plastics with uncompromising quality and service. We currently have four divisions that are located within two manufacturing sites. All are certified class 10,000 / ISO Class 7 cleanrooms.

We can identify the right manufacturing solution for any project. We have extensive experience in a wide range of injection molding techniques including:

  • Automated injection molding
  • Multi-cavity tooling
  • Micro molds and micro molding
  • Servo-controlled de-molding capabilities
  • Insert molds, overmolds, and automation integration
  • Transfer molding
  • Compression molding

Contact us today at 763-331-3800 to discuss your next medical molding project.

Silicone Injection Molding vs. 3D Printing
Article Name
Silicone Injection Molding vs. 3D Printing
A comparison of silicone injection molding versus 3D printing including the equipment utilized, the key advantages, and common use cases of each process.
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ProMed Molding
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