2K or Co-injection molding supports the production of products composed of multiple materials or colors, providing technical and design freedom. The name 2k is somewhat misleading, as it’s possible to combine not just two components but three or more, which is why the term multi-component is now preferred.
An interesting trivia fact is the reason many make use of the term 2K or 3K in relation to this technology. Why use the letter K if “Components” starts with C? The reason lies in the fact that this technology originated in Germany, where the word for “component” is spelled with a K.
Advantages of Multi-Component Injection Molding Technology
Like all machines at Rion, the multi-component injection molding machines come from top German and Austrian brands – ARBURG and ENGEL. These machines, combined with our professional technological guidance, allow for the production of the highest quality products. This efficient method eliminates the need for secondary assembly processes and significantly reduces cycle times. It means there’s no need for the complicated logistics involved in storing and transporting intermediate goods. Automation can be combined into the multi-component injection molding machines, and a fully automated production cell can be designed for more complex products.
Technologies Available at Rion
At Rion, you can find several multi-component injection molding technologies. For example: a rotary table technology injects one component, then after mold rotation injects the second component. There’s also index technology, where only the insert inside the mold rotates, not the entire mold.
Another interesting option is the retracting core technology, which allows, with some minor modifications, to produce multi-component products with a regular injection molding machine.
How to Choose What’s Right for Your Product?
If you are considering multi-component injection molding, it’s best to do it during the design stage, and it’s recommended to consult with us as early as possible. Doing so will allow us to find the optimal technology to match your product. It’s no secret that multi-component processes require expensive molds, so early thinking and minor product adjustments can lead to significant savings in the process.
At Rion, multi-component injection molding can be performed for products ranging from about half a gram to hundreds of grams in weight. In terms of raw materials, we can recommend materials suitable for the process, as it’s usually desirable for the materials to be compatible with each other, to create a strong chemical adhesion and eliminate the need for physical connectors. After a comprehensive analysis, we can also recommend changes to the product geometry, which are sometimes necessary for an efficient process.
Successful Case Studies
Collaborations with our customers have often led us to find creative, out-of-the-box solutions. An example of this can be seen in a recent project. A certain customer had a product that was already produced at Rion with a regular injection molding machine, for which we set up a dedicated automation system. The customer developed a similar product, but this time it required two components. Manufacturing the product on a two-component injection molding machine required setting up a new expensive automation system that made the project unfeasible.
After consideration, we decided to “think in reverse” – to treat the automated system as a given and turn the production process on the regular machine into a two-component by adding a dedicated screw as part of the mold. This significantly reduced the cost for the customer. To read about another customer case study where we used two-component injection molding, click here.
