Xiamen Mingcai membranepanel is an operating system that integrates key functions, indicating components and instrument panels. It consists of four parts: panel, upper circuit, isolation layer and lower circuit. It is a light touch-on normally open switch. The membrane panel has a rigorous structure, beautiful appearance and good sealing performance. It has the characteristics of moisture resistance and long service life. Widely used in electronic communication, electronic measuring instruments, industrial control, medical equipment, automobile industry, smart toys, household appliances and other fields.
When the panel is not pressed, the membrane panel is in a normal state, the upper and lower contacts are disconnected, and the isolation layer isolates the upper and lower circuits; when the panel is pressed, the contacts of the upper circuit are deformed downward, It overlaps with the lower line and turns the line on. The connected line sends a signal to the external connecting instrument (substrate) to realize its corresponding function; when the finger is released, the upper circuit contact bounces back and the circuit is disconnected. The loop triggers a signal.
Xiamen Mingcai membrane panel inspection steps
1. Material inspection: Panels, substrates, silver paste, carbon ink, spacers, adhesives, adhesives, reinforcing plates, and insulating printing should comply with the drawings.
2. Shape comparison: the shape, conductor lines, insulation treatment, lining plate combination, etc. should comply with the drawings or provide physical samples.
3. Check the color: use the visual inspection method to compare with the sample or color card to see if there is a color difference, and use a color difference meter to compare the color requirements.
4. Peel strength test: The peel strength of the glue should not be lower than 8N/25mm.
5. Ink adhesion inspection: The ink is attached with a transparent tape to ensure that there is no air bubbles and then peel off quickly after 10 seconds, and there should be no ink drop phenomenon. After the insulating ink is dry, press the ink surfaces against each other for 24 hours to ensure that the insulating surfaces do not stick to each other. After sticking with pressure sensitive tape for 1 minute without air bubbles, it peeled off quickly and no ink fell off.
6. Check the dimensions: the allowable range of unmarked tolerances in the drawings must meet the standards, and the rest meet the requirements of the drawings.
7. Check the appearance: the panel should not have obvious defects, such as missing strokes of characters; stains, light transmission points; deinking, stains, scratches; transparent window overflowing glue, residual glue, etc. There is no offset phenomenon, such as printing overprint, combination of upper and lower line keys, line and key sheet, panel and key combination, bubbling and substrate at the panel keys. The size of punching burrs and extrusion bending should not be greater than 0.2mm, and the position should be toward the side without conductors.
8. Membrane panel bubbling detection: equal height and balanced force. Flat type: 57~284g force, touch feeling: 170~397g force.
Membrane panel structure
1. The panel layer is generally made of exquisite patterns and characters by silk-screening on PET, PC and other colorless light-transmitting sheets less than 0.25MM. Because the main function of the panel layer is to play the role of logos and buttons, the selected materials must have High transparency, high ink adhesion, high elasticity, high toughness and other characteristics.
2. Top layer
The main function of the surface glue is to closely connect the panel layer and the circuit layer to achieve the effect of sealing and connection. This layer generally requires a thickness between 0.05-0.15MM, with high viscosity and anti-aging properties; in production Generally, a special double-sided adhesive for membrane panels is used. Some membrane panels are required to be waterproof and high temperature resistant, so the surface adhesive must also use materials of different properties according to needs.
3. Control circuit upper and lower layers
This layer uses polyester membrane (PET) with good performance as the carrier of the switch circuit pattern, and uses a special process to screen-print conductive silver paste and conductive carbon paste on it to make it conductive. Its thickness is generally 0.05-- Within 0.175MM, the most common is 0.125MM PET.
4. Sandwich layer
It is located between the upper circuit and the lower circuit layer and plays the role of sealing and connection. Generally, PET double-sided tape is used, and its thickness varies from 0.05 to 0.2MM; when selecting the material of this layer, the overall product should be fully considered. Thickness, insulation, circuit key pack feel and tightness.
5. Back Adhesive Layer
The use of adhesive is closely related to what material the membrane panel is attached to. Common double-sided adhesives, 3M adhesives, waterproof adhesives, etc. are commonly used.
How to paste the membrane panel
1. Clean the surface to be attached to the membrane panel (the surface to be attached is required to be smooth, rust-free, oil-free and dust-free);
2. Compare the size (put the membrane panel to the place to be pasted to compare the size and position);
3. Then peel off the centrifugal paper at the bottom of the membrane panel by about 10mm from the edge;
4. Then put the membrane panel in the corresponding position and stick it to a part, and then slowly tear off the remaining centrifugal paper (under the condition that the angle cannot exceed 15 degrees), and then paste it to the corresponding position in turn;
5. During the pasting process, if the membrane panel with the centrifugal paper on the reverse side is torn off, it needs to be placed first, and the reverse side should be placed upward to prevent it from sticking to other objects and affecting the pasting;
6. Matters needing attention: Paste cannot be repeated, it needs to be done at one time; the tearing angle cannot exceed 15 degrees; when trying to press the feel, it must be placed flat on the table before pressing, and cannot be pressed in the air, otherwise it will be Affect the service life of the membrane panel.
Membrane Panel Switch Performance Overview
The soft membrane lined between the membrane panel switch and the membrane key switch is to reduce the pressure on the keys and prevent failure, and should be retained;
The membrane key switch generally has a two-layer structure. The upper and lower contacts are lightly pressed to contact the contacts to achieve the switch closure. Therefore, in the production process, do not remove the intermediate layer of soft membrane and bubble membrane, but should retain it. Let's talk about the performance of the membrane key switch.
1. Durability: The life of the membrane panel key switch can generally reach more than one million times. The reason for such a long life is that the action of the switch is only realized by the vertical direction of the elastic membrane; 10,000 times of creep, but due to the small amplitude of creep, only 0.10.3mm (that is, the switching stroke), and the rationality of material selection, it is far from reaching the yield limit of the membrane, so the membrane material can accept one million times. above life without deformation.
2. Good sealing function: Because the membrane panel key switch is an integral sealing structure, the contacts of the switch are not corroded by harmful gases and are not easy to be oxidized; it has the characteristics of waterproof and dustproof, so it is more suitable for various harsh conditions.
3. Rich color and elegant shape: The membrane panel key switch can be characterized in the design of the color pattern according to the user's design concept, and the comprehensive characteristics of the beauty of the material, the beauty of the decoration and the beauty of the craftsmanship are shown in the decoration effect.
4. Reduce the supporting cost of electromechanical products: traditional mechanical switches need to be welded during installation, and even need to be firmly supported; while the installation of membrane key switches is a sticky type, just remove the adhesive tape and stick it on the surface of the whole machine Insert its lead into the circuit socket of the whole machine to connect the circuit.
5. Small size, light weight and reliable structure: The membrane panel key switch can be arranged and combined with a membrane keyboard in design, and its configuration density is high, and it is composed of multiple layers of membrane, thus reducing the volume and quality. Improved reliability.
