Companies across various industries are constantly seeking ways to bring complex and highly functional products to market with efficiency. One of the most sophisticated techniques supporting this is undercut molding, a specialized aspect of plastic injection molding that plays a vital role in creating intricate designs and functional components.
What is Undercut Molding?
Undercut molding refers to the creation of complex geometries in molded parts that include features such as protrusions, recesses, or hooks, which extend below or around the parting line of the mold. These undercuts often complicate the removal of the molded part from the mold due to their positioning and shape, requiring specialized strategies to achieve clean demolding without damage to the part.
An undercut feature can be either internal or external. Internal undercuts are typically found inside the part, like threads or internal snaps, whereas external undercuts are features on the outside, such as hooks or grooves. Achieving these geometries is essential for creating parts that meet specific mechanical or aesthetic requirements.
Undercut molding is integral in many designs where components need to interlock, snap together, or have moving parts. The challenge lies in producing such components without sacrificing the structural integrity of the product, while keeping the production cost-efficient. Creating such molds tends to increase production costs, so it is recommended to recur to undercut molding only when needed.
How is Undercut Molding used in Plastic Injection Molding?
Undercut molding is a very efficient technique in plastic injection molding, a process widely used to mass-produce parts by injecting molten plastic into a mold. Plastic injection molding offers immense flexibility in terms of material and design possibilities, making it one of the most popular methods for creating everything from small, detailed components to larger, structural parts. Other materials can be employed with this method; however, plastic is the most used for medical device manufacturing.
When working with injection molding, the mold is designed in such a way that parts are easily ejected once they’ve cooled. However, when undercuts are involved, the standard two-part mold structure becomes insufficient. Undercut features, by definition, are challenging to release from a conventional mold because they interfere with the clean ejection of the part.
To solve this, engineers and mold designers use various solutions, including side-actions, lifters, or collapsible cores.
- Side-actions are mechanical devices integrated into the mold that slide into place during the injection process, creating the undercut, and then retracting to allow the part to be ejected.
- Lifters are components that lift away from the part during ejection, allowing for more complex geometries.
- Collapsible cores are designed to create internal undercuts, such as threads, and then collapse or retract after molding, enabling ejection without damage to the part.
By incorporating undercut molding into the injection molding process, manufacturers can significantly expand the range of possible part geometries and functionalities while retaining the cost-effectiveness of mass production.
The Advantages of Undercut Molding in Product Development
Undercut molding offers several key benefits for manufacturers engaged in product development:
- Design Flexibility: The ability to incorporate undercut features into a product design allows for greater functionality and more complex assemblies.
- Cost Efficiency: While designing and producing molds with undercut capabilities requires careful planning, the long-term benefits in terms of production efficiency, reduced part count (due to fewer components needing assembly), and overall reliability make it a cost-effective solution.
- Improved Aesthetics: Undercut molding allows for smoother and cleaner finishes, reducing the need for secondary operations like trimming or polishing.
- Functionality: For products that require tight-fitting, secure connections or moving parts, undercut molding provides the solution with its ability to produce intricate interlocking parts.
How Our Company Supports Projects with Undercut Molding
At ARRK North America, we specialize in providing comprehensive product development support services, including undercut molding, urethane casting, and low-volume production, amongst others. We work closely with our clients from the early stages of design to final production, ensuring that every component meets the necessary standards of quality and precision.
Undercut molding is a critical technique that expands the possibilities of plastic injection molding. By enabling the production of complex geometries, this method provides manufacturers across industries with the tools they need to create more functional, efficient, and aesthetically pleasing products. With our expertise in product development, we are here to help you make the most of this powerful technology.
Our team of experienced engineers and mold designers is adept at tackling complex projects that require advanced techniques such as undercut molding. We can help you navigate the intricacies of undercut molding to bring your innovative designs to life. Get in touch with us to get a quotation. Learn more with our blog content, such as, 10 Reasons To Reduce Production Cycle Times & How To Do It or Production Of Parts On Demand: Advantages And Disadvantages.
