Flexible Rubber Keyboard: How are Bendable Keypads Made & Why Do We Use Them?

What Is a Flexible Keyboard?

A flexible keyboard is a keypad made from silicone or other soft polymers that bend and flex. It could be a qwerty, numeric or even a customized keyboard designed for any application. They’re durable, water resistant and virtually indestructible.

Where Are They Used?

You can find flexible silicone keyboards all over the world in many industries such as agricultural, automotive, medical, industrial and more. They are well suited for almost any environment.

Why Flexible Keyboards?

Today, consumers and machine operators are looking for dynamic and mobile technology solutions. A flexible keyboard can be designed to fold up and fit in a pocket or rolled up to create desk space. It is light and bendable, allowing for easy transportation in a limited space. They often use the same types of connectors as rigid keyboards that work with USB wire harnesses for plug-and-play simplicity.

How are Flexible Keyboards made?

Silicone keypads are made by a process called compression molding. Think of the compression molding tooling like a waffle iron, with metal top and bottom halves. Instead of two identical halves like the waffle iron, the bottom half has the product design cut into it, while the top has the reverse of the design to allow the silicone to fill in the empty space.

The machine operator places raw silicone material into each cavity of the tooling and closes the halves. The tooling is heated up to a specific temperature range so the silicone will become more viscous, flooding the open spaces.

The production team at RSP can determine the amount of material that is needed by reviewing the product design and leveraging their vast experience. With this knowledge, RSP can cost-effectively make your product without an unreasonable amount of wasted material.

The RSP engineering team also determines the amount of time the silicone tooling needs to be heated for the silicone to properly spread through the cavity. This is called a cycle time. Cycle times can range from two hundred to seven or eight hundred seconds, depending on the size of the silicone part. Once the cycle time is complete, the tooling opens and the technician operating the molding machine will remove the part from the tooling with compressed air to detach it.

At this stage in production, there is a blank keypad without printed graphics. In some cases, where there is a printed overlay around the keypad or a touch screen type display with icons, printing isn’t required since the key is defined in other ways. However, most keypads have printed graphics. Graphics can be put on a silicone keypad in several ways including:

  1. Printing – adding ink directly
  2. Laser etching – selectively removing ink coating

Printing graphics on a keypad is often done by screen printing. The RSP production team would create a silk screen specifically designed for your product. The porous screen is blocked out around the desired image so that as ink is pushed across the screen, it only flows through where it is not blocked out so that the image is printed on the substrate. Whether it is a logo, text, shapes or other printed graphics, the screen only allows the ink to travel through it and onto the keypad in those specific locations.

Laser etching is another process for placing graphics onto a keypad, but there are several more steps. For example, you may want to have text printed in white on a black keypad. In this case, the silicone keypad would be molded in its natural semi-clear color. Then the production team would spray paint a coat of white followed by a coat of black across the entire surface. The laser-etching machine is then programmed to etch a certain depth into the keypad. In this example, this depth is the thickness of the black paint. The laser-etching machine would etch away the text, logo or other printed graphics, removing the black layer to show the white layer beneath. If using the semi-clear silicone, the image would be visible as white in normal use and could also be backlit for additional functionality.

As you can see, there are many variables when it comes to designing flexible keyboard and keypads. RSP Inc. has vast experience making these products, and we are sure we can assist you no matter where you are in the process. Reach out to our team so we can assist you on your product development journey.