An inorganic Si-O backbone is combined with organic functional groups to form silicone rubber. High-temperature resistance and flexibility across a broad temperature range are owed to the silicon-oxygen connection.

Using either peroxides or polyaddition curing, the silicone polymer is combined with reinforcing fillers and processing aids to create a stiff gum that can be cross-linked at extreme temperatures. The silicone becomes a solid, elastomeric substance after it has been cross-linked.

At Protolab, silicone rubber keypad manufacturer India, we heat cure all our silicone materials, resulting in HTV silicone (High-Temperature Vulcanised) products. Consequently, we’re in total command of the production process and can ensure the highest levels of product quality. The use of silicone rubber material is the distinctive feature of the custom rubber keypad. In its natural form, silicone rubber has a viscosity similar to that of a liquid gel.

This is often a two-step procedure. First, a mould is prepared, and silicone rubber is put into it. Second, the curd is heated and pressurized to form a paste. As soon as the process is complete, the silicone rubber goes from a liquid state to a solid one.

You’d want to know more about how this fantastic product is produced and how it functions. To learn more, continue reading.


How are silicone rubber keypads made?

There are several steps involved in how silicone rubber keypads are made. Some of them include:


1. Making the Tool 

Two-plate mold tools are required for elastomeric keypad designs, which include a silicone compression molding tool (top half) and molded keypad (bottom half) (bottom half). CNC milling machines and EDM machines may be utilized to create mold tools. For optimal results, the molding tool is heated to a pre-heated state.

Uniquely designed silicone rubber keypads provide excellent feedback when pressed. .060 inches of keypad distance is required for the best tactile experience. The actuation force of each key on the keypad varies. While the actuation force of a flat key ranges from 20 to 100 grams, that of a cone-shaped key may range from 20 to 250 grams.


2. Choosing the Right Type of Silicone Rubber 

Silicone rubber keypads are made from two types of silicone material: gum stock and liquid.

Platinum-cured silicone rubber, which makes liquid silicone rubber, is very resistant to high temperatures. The viscosity of liquid silicone rubber is quite similar to petroleum jelly. There are several advantages to employing liquid injection molding to develop bespoke features.

When it comes to gum stock silicone rubber, it’s like dough or thick putty in appearance and texture. First, several vast batches of the solid silicone rubber are put together simultaneously. Once the components have been combined, a peroxide catalyst is often added.

To make gum stock silicone rubber, the cross-linking process is often halted. Sheets of silicone that have been moderately cross-linked are then formed.


3. Preparation of the silicone mold 

An efficient approach for producing industrial electrical goods is compression molding of silicone rubber. In this instance, we’ll focus on it heavily. The silicone preforms must first be prepared (what we put into the tool).

In its raw state, silicone rubber resembles play-doh. Silicone is precisely measured in each molded item. Silicone performs meticulously weighed and cut by hand. To ensure that each cavity is filled, we begin by placing the chopped pieces into each tooling cavity.


4. Adding Preforms to the Mold

Next, we’ll need to feed the silicone rubber material into the mold tool so that we can create the elastomeric keypads. Compression molding presses are loaded with pre-assembled silicone rubber preforms. We then apply a specified amount of pressure to the clamp to produce high-quality rubber keypad components.

If the silicone preform doesn’t fit the mold’s cavity correctly, it won’t work properly. The cavity will be fully stocked with raw materials to avoid excessive flash. Additional flash describes any excess material still connected to molded rubber keypad pieces.

Keypad molds are formed by applying pressure, heat, and time to a silicone performance. The silicone rubber keypad is formed in the mold cavity by applying pressure and heat.


5. Removing and Curing the Tool’s Keypad

In most cases, molded silicone rubber keypads are cured at 180°C for roughly 5 minutes. The ideal temperature and pressure must be maintained until the rubber is fully cured.

After hardening, the silicone keyboard is removed from the mold tool.

The removal or ejection procedure requires gloves and a pressurized air hose. They are required because the silicone rubber keypads in the mold tool are very hot. In addition, the pressurized air hose aids in removing the silicone keypads from the device.


6. Silicone keypads are screen printed.

Keypad functions must now be specified for the silicone rubber keypads. Screen printing, silicone ink, laser marking, and label plate engraving are all standard means of printing silicone rubber keypads.

Nonetheless, we employ screen printing in our production to ensure the best rubber keyboard and the most satisfactory possible quality control. Additionally, it is a suitable strategy for mass production. Screen printing needs two things: screen print color and a mesh with holes.


How does a rubber keypad work?

Silicone keypads and carbon pills are made similarly. Silicone contains conductive carbon. When a rubber button is pressed, carbon particles on the board hit the switch, allowing electricity to flow. Likewise, pushing a rubber button causes a tactile effect. 

When pushed, the electrical contacts of a silicone keypad send forth electrical impulses. One section of the silicone web is compressed with each keystroke. The effect is complete when the carbon/gold pill on the key makes contact with the PCB contact below. There are several advantages to using simple switch connections. Unlike mechanical keyboards, silicone keypads may be used for a long time.

We hope you find this article insightful. Get in touch with the silicone rubber keypad manufacturer for any concerns.