Compression molding silicone rubber keypad manufacturing process

Compression molding silicone rubber keypad manufacturing process

Silicone rubber keypads, sometimes also called elastomer keypads, are usually made of silicone with unique properties through high-temperature compression molding. They are key components in consumer electronics and industrial electronics applications. High-quality silicone rubber keypads follow strict production processes. Its manufacturing process is critical to the quality and performance of silicone rubber buttons. What does the complete manufacturing process of silicone rubber keypads include? Now we will introduce the silicone rubber keypad manufacturing process step by step, and some key steps:

How are silicone rubber keypads made?

The manufacturing process of silicone rubber keypads usually includes mold manufacturing, silicone compound preparation, molding, secondary vulcanization, surface treatment, etc.

Step One: Mold Design and Development

Manufacturing tools are the first step in the manufacturing of silicone rubber keypads. Advanced EDM and CNC milling machines allow us to quickly manufacture the required tooling in-house based on customer-approved design drawings. Molds are usually made of high-quality metal materials to ensure the accuracy and durability of the mold.

Step 2: Prepare materials

Select the appropriate hardness and performance of the silicone material according to the quality and specifications of the silicone rubber keypads required by the customer, and add appropriate amounts of additives and pigments for mixing. In order to ensure the consistent quality and performance of silicone keypads, the addition ratio of various ingredients needs to be strictly controlled during this process. In addition, prepare various tools and other materials required for the production process.

Step 3: Compression molding

Curing is a critical step in molded silicone rubber keypads. The operator manually places the pre-made silicone materials on the mold surface one by one, then closes the mold and maintains heat and pressure until it forms the structure of the mold. The mold must be neat and clean before placing the silicone rubber on the mold. The temperature, pressure, and time are key to the compression molding silicone rubber keypad's precise dimension and appearance quality.

Sometimes, To let a silicone keypad provide the user with electrical contact with any device, carbon pills are added to the bottom of the mold before the silicone is placed and molded.

Compression molding silicone rubber keypad

Step 4: Add multiple color blocks to the preliminary silicone rubber keypads

Prepare the colored silicone rubber before molding. Next, it is manually placed on the base mat. The initial silicone keys with the colored silicone will fuse to form the keyboard base. The keys will retain their specific color and only the tops of the keys will be visible through the bezel.

Step 5: Secondary vulcanization (optional)

The vulcanized silicone rubber keypad is a semi-finished product. Whether secondary vulcanization is required depends on customer requirements. This process's purpose is to remove the remaining vulcanizing agent decomposition products in the keys to improve the performance of the silicone rubber keypads.

silicone rubber keypad secondary vulcanization

Step Six: Remove burring

Silicone rubber keypads that come out directly from the mold generally have burrs. These burrs are usually cut by hand. Some manufacturers use a punch press to remove the burrs from the silicone keypad sheets.

Step Seven: Surface Treatment of Silicone Rubber Keypad

To realize text and patterns on the surface of silicone rubber keypads and increase their appearance quality and tactile feel, we usually perform surface treatment on them by silk-screen printing, spraying oil, or laser engraving.

Silk screen printing
The molded silicone rubber keyboard is placed into a fixture surface and a roller is passed over the keys before printing to remove dust and dirt from the surface. The template is also placed over the silicone keyboard, which means the keytops can only accept ink from the exposed area of the template. It is important to note that each color has a separate template. After screen printing, it generally needs to be baked at a high temperature to solidify the ink on the surface of the silicone button in a short time. Ink quality, correct baking time, and temperature are the keys to the quality of screen printing of silicone rubber keypads.

Spray Oil
Common spray oil methods include color oil, matte oil coating, and PU coating. Before spraying the topcoat, clean the silicone rubber buttons and spray a coat of primer on its surface which can remove dust, and grease and increase the adhesion between the topcoat and the silicone. The silicone rubber keypads that have been top-coated need to be placed in an oven for heating to solidify the topcoat.

Laser engraving
Place the silicone rubber button on the spray stand and use a special spray gun to spray black oil on the front of the button. Drying is required after spraying. Drying time generally takes several hours to 24 hours. Next, use a laser engraver to remove the unwanted black areas on the keypad surface.

Silicone Rubber Keypad silk-screen printing
Silicone rubber keypad Laser engraving
Silicone rubber keypad spray oil

Step 8: Quality Control

Quality inspection is the last production process of silicone keypads. These inspection items include dimensional, operating pressure test, hardness, stains, color, font clarity, alcohol abrasion test, etc. The above inspection items ensure that the quality of the silicone rubber keypads is consistent and meets the initial design's requirements.

The above is the complete process of manufacturing silicone rubber keypads. The manufacturing process of molded silicone rubber buttons involves key steps such as manufacturing tools, molding, edge removal, and surface treatment. Each step needs to be strictly controlled and operated to ensure consistent quality and a low risk of defects in the silicone rubber keyboard.

Yuanyi has provided customized silicone rubber keypad manufacturing services to customers in multiple industries. More than 10 years of experience in silicone rubber button manufacturing and familiarity with the process enable us to provide customers with high-quality silicone rubber keypads. If you are interested in our silicone rubber keypads, contact our professional engineering team now and they will take you to learn more about our manufacturing capabilities and processes.

How are silicone rubber keypads made?

QUICK LINKS

PRODUCT CATEGORY

ABOUT

CONTACT