What is a tact switch?
Before we understand the principle of the tact switch, let’s first understand what a tact switch is. The tact switch is a common electronic switch and belongs to the mechanical action category. Composed of plastic parts, base, slingshot shrapnel, handle button, and cover plate, it is a kind of component that can be connected with the circuit by lightly tapping when in use, and it will be disconnected when the hand is released.
A brief description of the touch switch:
(1) Tact switch is also called key switch, It is generally called by its outer dimensions: for example, 6*6*5, which is its length, width, and height. It is a kind of electronic switch, which is different from the wall switch of home. The difference lies in the different application fields and its own structural functions are also different, so it is called an electronic switch. Divided into: push type and surface mount touch type. The difference between the two types is the size and the welding form. The push type is mainly a plug-in type with a larger volume; the surface mount touch type is mainly a patch ultra-thin type. The light touch switch is made by pressing the handle to press the shrapnel to conduct the contact stroke of the shrapnel and the shot point. Therefore, it can be divided into three types, one is normally open, one is normally closed, and the other is double action. There are also three types of switch pins: one is a two-pin switch, a three-pin switch, a four-pin switch, and a five-pin switch.
(2) The switch evolved from the Guozi slice, which was the first membrane switch to be used. The structure is single and the production speed is fast. However, the product has a low lifespan and a single use performance cannot meet market demand. According to the increasing demand for product performance, simple Guozi tablets have been gradually eliminated by the market. What follows is that we touch the switch, and the principle of use is the same. It is an upgraded version of Guozi Pian, and its heart is Guozi Pian. It looks the same as Iron Man.
In the initial stage of use, consumers only have requirements for the quality and performance of the product. As the market improves and the consumption level increases, the quality and performance of the product begin to fail to satisfy consumers. Anyone who is familiar with this switch knows that the switch has its feel. Simply put, it is the strength of the switch. Touch, key, toggle, and jog are all strength parameters. Industry standard: micro power 30-100gf, button power 250-400gf, dial power 200-400gf, light touch 50-400gf. The feel is directly related to the strength. The smaller the positive and negative tolerance range of the strength, the better the feel. The domestically produced shrapnel has a larger positive and negative tolerance range, with a value of plus or minus 50; South Korea’s shrapnel has a relatively medium value of plus or minus tolerance, with a value of plus or minus 30; imported from Japan The shrapnel is also the best shrapnel in the world. The positive and negative tolerance range of the Japanese ternary shrapnel used by Pinzan is very small, and the value is plus or minus 10. Summary: The higher the precision of the shrapnel, the better the touch of the switch.
The working principle of the switch: when you press the switch button, the switch can be turned on. When the button is released, the switch is turned off. The internal structure of the switch is turned on and off by the force of the metal shrapnel. The metal shrapnel mentioned in the working principle is referred to as shrapnel, and there are two types of shrapnel materials. The shrapnel is made of phosphor bronze and stainless steel. The electroplating process is silver-plated and gold-plated. Pinzan’s gold-plating and silver-plating processes are both above 0.3um. The electroplating process directly affects the electrical performance of the product and the oxidation resistance of the product.
(3) There are many reasons for the bad hand feeling, the structure of the switch itself is unreasonable, the material of the shrapnel and the electroplating process are not up to standard, the shrapnel is deformed, and the error range of the shrapnel is large. How do we ensure its feel, develop and produce a reasonable structure, use stainless steel shrapnel, control the error of the shrapnel and the defective rate of the shrapnel. The feel of the product will directly affect the sales and reputation of the product. A good brand and a good product have very high requirements for the switch feel. The quality of the hand feel has a great impact on the life of the switch itself. The life of domestic shrapnel is between 3-5W times; the life of Korean shrapnel is between 5-8W times; the life of Japanese ternary shrapnel used by Pinzan is 10- Between 100W times. A good shrapnel directly affects the feel, life and quality of the switch.
The height of the button handle can be customized according to the requirements. The thin surface of the patch has no button handle and is covered by the film. The principle is the same. The plug-in handles have heights of 1.0, 1.5, 2.5, 3.5-28mm, which are customized according to customer product requirements. There are two types of internal structure: one is silent, the other is sound, and the other is general in the market, which is sound, with a crisp sound of “tick”. There are many types of button strengths: 70gf, 90gf, 120gf, 160gf, 180gf, 200gf, 250gf, 300gf, 400gf and other customized strengths. The selection of button strength is based on different products. For example, mouse products, children’s products, medical products, and smart home products generally use light strength, and household appliances, automobiles, air purifiers, and sports equipment generally use gravity. It is positioned according to the market demand of the product. The key strength and the mechanical life of the touch switch are closely related. The lighter the strength, the higher the life. Life: 3W-5W, 5W-8W, 8W-10W, 10W, 20W, 30W, 50W, 100W times life. The life span has a lot to do with the choice of shrapnel for the switch. The life of domestic shrapnel is 3W-5W, 5W-8W; the life of Korean imported shrapnel is 8W-10W; the life of Japanese imported ternary shrapnel is 10W, 20W, 30W, 50W, 100W.
(4) The switch is turned on and off by the force of the internal metal shrapnel. The distance between the metal piece and the bubble point of the base is called the stroke. The stroke is divided into long stroke, short stroke and medium stroke. The stroke is determined according to the structural size and performance requirements of the switch itself. The shortest lower limit of the short stroke is 0.8mm, which is called the small stroke and generally uses the ultra-thin type. The middle stroke is between 0.13-0.3mm, which is generally used for plug-in type. The long stroke is between 3.0-0.5, which is generally used in silicone keys and gravity products. The smaller the stroke, the lower the button sound, and the higher the stroke, the louder the sound and the lower the life span. The stroke can be set according to the mechanism of the switch itself, which can achieve sound and silent effects. Factors affecting the product: The most direct factor in the length of the stroke is the action force. The action force is usually divided into: light force (below 120g), gravity (above 300g) and standard force (150-250g), the shorter the stroke, the switch The lighter the strength, the longer the life span; the greater the stroke, the greater the strength, the longer the life span; the mid stroke is the most standard stroke, and its life span is moderate and very ergonomic, so it is widely used.
Post time: Jul-21-2020