How Overmolding Elevates Your Part Designs
Are you looking for a unique way to make your product stand out by combining multiple materials and colors? Do you need new ideas to improve its ergonomics and functionality? ICOMold by Fathom’s overmolding service can help you with those objectives.
What is overmolding?
It’s the process of using plastic injection molding to mold a part. Once it has cooled, a second material is molded over it, using the same tool. The two layers are either chemically or mechanically bonded to each other, creating a single part with two colors and textures. Usually, a harder material is overmolded with a softer one to create a grip or design accents.
Applications
Over Plastic: This is the most common form of overmolding. First the primary, more rigid plastic component is molded and then a softer, more flexible plastic is molded over it.
Over Metal: Molding plastic to metal is often used to add plastic handles to metal tools and components or to encapsulate a metal part within plastic.
What does overmolding make possible?
ICOMold by Fathom’s overmolding service enables you to create products that have both hard and soft areas. An excellent example is a vehicle armrest, which needs to be rigid but has a cushioned area for your elbow to rest on.
In many cases, manufacturers select it for cosmetic reasons – to provide a stylish appearance that’s attractive to consumers. Contrasting materials and finishes can bring a unique aesthetic to many types of products. For some applications, a soft area is required for ergonomic reasons, such as adding a non-slip grip to the handle of a screwdriver.
Overmolding enables you to combine two materials and finishes using a single tool. This saves you time and money during the production process, but also eliminates the need to manually assemble or glue the parts together. It may also eliminate other secondary operations, such as priming, painting or coating.
Benefits of Overmolding
Improved aesthetics: You can use it to increase the consumer appeal of a wide range of products by combining different colors and textures in a single part. For example, toothbrushes are often overmolded to create colorful handles. Examples of elements that can be designed as overmolds to increase their consumer appeal include grips, handles, knobs and armrests.
Improved Ergonomics: You can combine two different types of plastic resins and two colors into one part. This means you can have a rigid plastic body and then overmold soft silicone grips onto areas that an end-user would grab, such as the handle of a tool.
Shock Resistance: Adding a soft surface onto a rigid part can improve its shock absorption. That can extend its life and can help protect it against physical impacts better than non-overmolded products.
Eliminates Fasteners and Adhesives: By incorporating two adjoining parts into an overmold, you can eliminate the need for fasteners and adhesives that would otherwise be needed to join them together.
It Can Save Money and Time: One of the biggest benefits of this process is saving money and time. Since it can be completed with two runs through our in-house injection molding process, it’s not necessary to outsource it as a secondary process at another facility. That saves money and time because you don’t need to schedule it with an outside supplier.
Special considerations for overmolding
This process is not without its limitations. One consideration is that the two materials must be compatible, chemically and thermally. Since the first piece is put back into a plastic injection mold, The first piece must be able to withstand the temperature needed to melt the second material.
Also, you will need to make sure the two resins don’t react to each other. That can cause the overmold to fall apart.
Finally, it’s important to remember that it’s not a straightforward injection molding process like making a part out of a single material. A high level of experience is required to do it right. At ICOMold by Fathom, we’re experts at working with this complex process. We can help you optimize your part design, materials and tooling to deliver overmolded parts that meet your requirements and delight your customers.
Advantages/disadvantages
Advantages
Produce unique designs with less tooling: Overmolding eliminates the traditional injection molding process steps required for producing and assembling two parts. The part and its overmold are made using a single tool. That saves time and money.
Eliminate finishing steps: Depending upon the part design, it may replace secondary operations like painting or coating.
Replace glued components: In some cases, a design may require a window or other element to be glued to an injection-molded part. But most glues tend to weaken over time. Overmolding may be used to eliminate this step and hold this piece in place. Bonding two parts together via overmolding tends to result in a higher-quality product.
Enhanced design flexibility: This process empowers designers to think bigger and consider more striking possibilities.
Disadvantages
Potential design challenges: Great care must be taken during initial product design, material selection, and tool design to ensure that the part can be overmolded successfully.
For example, there must be clear-cut boundaries between the underlying part and its overmold. This is not only for cosmetic reasons but to help ensure adhesion between the two surfaces. This can also be enhanced by adding design elements that help keep the overmolding attached to the part below it.
In some cases, masking and painting may be a better solution to achieve the appearance and functionality you need.
For best results, consult an expert at ICOMold by Fathom to review your design and help you decide whether overmolding is the right solution for you.
Traditional Technologies That Could Benefit from Overmolding
Products that require soft-touch elements that are currently made using fabrics or multi-part assemblies can potentially benefit from our overmolding service.
Products where soft-touch elements and rigid parts are molded separately and then assembled are candidates for overmolding.
In cases where small electrical components or metal parts need to be protected from the elements, it may be a cost-effective solution to encapsulate them.
Why choose overmolding?
It enables you to create some truly unique and attractive products that can’t be made any other way. Whether you are looking to add style, improve the ergonomics or add protection to a part, overmolding can help you to achieve these objectives.
It enables you to accomplish all of this cost-effectively by combining two molding operations in a single tool. In the process, it can eliminate assembly and other secondary operations, saving you time and money.
Why choose ICOMold by Fathom for overmolding?
It requires high levels of engineering, material and tooling expertise. We have extensive experience helping our customers complete this type of project and avoid common problems. We can do the same for you!
