AIM Processing Small Plastic Parts Blog

Elastomeric overmolding (sometimes called “elastomer overmolding” or just “overmolding”) is a process in which a softer layer of material is bonded to a harder functional or structural component of a part. It can be used to improve functionality, to change the look of a part, or both. An example that most people are familiar with is a toothbrush handle with a soft, grippable section or covering. Other examples of overmolded parts include:

• Filters
• Electronic circuits and connectors
• Elastomeric grips or seals
• Threaded inserts
• Custom metal components
• Brackets and handles

The elastomeric overmolding process can be complicated, as it requires an in-depth understanding of the materials being used and close attention to the production process as the high pressures involved can damage parts if not monitored and adjusted. But, the beautiful and functional end products produced are well worth the effort.

A Bond with Many Benefits

Overmolding, and the physical and chemical bonds it creates, can deliver a wide range of product benefits, including:

• Textures that make handheld items easier and safer to use
• A greater variety of styles and colors for parts and finished products
• Enhanced opportunity for customization
• Vibration and noise reduction
• Protection from sharp corners or edges
• Defense against water, dust, and other contaminates, resulting in longer product life
• Greater electrical resistance
• Increased shock absorbency

It can also help lower the cost per part in some cases by eliminating the need for connectors, o-rings, and other pieces. And by taking those pieces out of a process, you can reduce the associated labor and produce finished parts more quickly as well.

No Room for Error

Successful elastomeric overmolding requires tremendous precision in order to ensure there are no gaps between the two materials and that they come together as one unified whole. Any misalignment can result in parts that are misshapen or subject to stresses that can result in fractures. It is a very specialized process that leaves no room for error.  

Overmolding Experts

The art of overmolding takes time and patience to perfect. Our industry veterans have the background and the expertise to produce parts that meet both technical specs and real world requirements. In fact, our reputation brings in inquiries and work from around the country.

Can your next project benefit from elastomeric overmolding? We’d love to talk with you about it, whether you ultimately choose to work with us or not. Give us a call or stop by.