Consider This When Designing Parts Which Require Overmolding

Overmolding is a specialized process of injection molding which incorporates the molding of one material (overmold) on top or around another (substrate). You see this today in many of your everyday medical, commercial and household products. This option typically gives the end user a better grip or more comfortable feel while utilizing the given instrument or device.

More and more engineers are looking overmolding as a viable option for their new designs. As in sports the professionals make it look easy but you bet it isn't as easy as it looks. There a many key factors that need to be considered when designing an overmolded plastic part and we will briefly discuss them below. We will also provide you with links to professional guidelines to help you get it right the first time.

The more simplistic your substrate geometry is the easier it will be to overmold it. Obviously if you have convex or concave parabolic shapes it will be more difficult to create tool steel to shut off on these surfaces making it very tough to mold without flashing. Keep the substrate design as simple yet elegant as you can. Remember that the injection molding process takes place with high pressures so good seals, support oposite the overmold and part orientation are keys to success.

If you would like to speak to us regarding overmolding please contact us. Please see the links below that will give you some ideas on what else to look out for when designing and overmolded part.

GLS Design Guide: