The quality inspection of membrane switches is a very important task. The first task of a successful membrane switch manufacturer is to establish a complete quality assurance system.
In the quality inspection of the membrane switch, in addition to paying attention to the color rendering of the ink that workers are very familiar with and the color reproducibility required by customers, it is more important to pay attention to the inherent quality of the membrane switch. Such as key operation force, life, peel strength, and high temperature, low temperature, constant temperature and humidity, test indicator for return line cathode, insulated cathode and withstand voltage. The following 4 are the standard specifications for quality inspection of membrane switches. Let's take a look together.
Appearance quality inclusions, stain inclusions are less than 2 /dm2. The length of inclusions and stains should not exceed 1mm. No accumulation is allowed, with at least 50mm scratches. The scratch is less than 1/dm2, the length of the scratch is not more than 20MM, and the depth and width are not more than 50um; scratches with a depth not exceeding 1um are allowed.
The color of the same batch of products should have no obvious difference, the color printing layer should have sufficient hiding power, and the color and structure below cannot be clearly seen by the reflected light. When printing a transparent ink layer, the double-color overlap should not exceed 1mm, and the color deviation caused by it should be allowed; the edges of printed characters and color blocks should not exceed 0.15mm.
The size of the membrane switch should meet the requirements. The parallelism and perpendicularity of the two adjacent sides of the membrane switch design shall meet the requirements. The center distance between adjacent wires at the end of the lead tape is usually 2.54 mm.
The peel strength of each adhesive layer of the membrane switch should not be less than 8N/25mm.