In designing your custom silicone rubber keypads, using undercut molding in the process can increase the secure placement, longevity and performance of your product. Undercut mold designs in conjunction with our advanced silicone injection process create a variety of specialty silicone rubber keypads. SiTECH specializes in not only traditional keypads, but also faceplates and covers for an array of devices.
Undercut designs in molds can be defined as a depression that allows the flow of silicone or a protrusion that prohibits the flow. This, in turn, will create a groove or channel that can aid in the placement of the part onto a printed circuit board (PCB). Undercut mold design is more sophisticated and technologically demanding than traditional mold designs. Because of this expertise in liquid silicone injection molding, specifically the behavior of liquid silicone when it comes in contact with a hot mold, it is needed in the design phase to ensure the proper placement of vital components to the mold.
Undercuts range in geometry and complexity, depending upon the final need of the part.  They can be square, rounded, deep and shallow. The options are vast in the design of custom silicone rubber keypads. Multiple undercuts can be designed into a single part, with each serving a different purpose; one undercut designed to hold a display window or glass, and another for sealing or fitting onto a printed circuit board. Multiple undercuts can also be utilized to secure the keypad to the PCB and that assembly to the final product.
Undercut designs can be useful in parts where there is not room in the design for pull through tabs. A pull through tab is a long thin cylinder designed into the part itself. It is pushed or pulled through the PCB to align and secure the keypad to the PCB. Holes designed to receive the tabs are smaller than the final diameter of the tab itself to provide a firm, secure hold. Undercuts can be used to provide a tight fit when tabs are not an option. In addition, undercuts can be used in conjunction with tabs to provide a wrap-around effect that will protect the PCB from many damaging elements.
Silicone is an excellent product to work with when designing undercuts into your final part. It has many advantages over other materials. Because of its chemical makeup and strong backbone, or bond, it is extremely durable and flexible. This, in turn, makes it highly resistant to many elements, which helps extend the life of your product. In addition, the method of liquid silicone injection molding has fast curing times, which reduces cycle times and the final cost of the finished product.
Undercut designs in custom silicone rubber keypads can help your product stand out in appearance with a clean finished look. It will aid in protecting vital components from moisture and other damaging conditions. Expertise in the industry is needed when designing undercuts into your product, especially when tight tolerances need to be achieved. At SITECH we have the experience to help with design and production and we partner with the most highly skilled mold maker in the industry to design and produce the highest quality silicone rubber keypads available.