Asbestos was added as an common ingredient to Brake Pads post-WWI, as car speeds began to increase, because research showed that its properties allowed it to absorb the heat (which can reach 500 °F) while still providing the friction necessary to stop a vehicle. However, as the serious health-related hazards of asbestos eventually started to become apparent, other materials had to be found. Asbestos brake pads have largely been replaced by non-asbestos organic (NAO) materials in first world countries. Today, brake pad materials are classified into one of four principal categories, as follows:
Non-metallic materials - these are made from a combination of various synthetic substances bonded into a composite, principally in the form of cellulose, aramid, PAN, and sintered glass. They are gentle on rotors, but produce a fair amount of dust, thus having a short service life.
Semi-metallic materials - synthetics mixed with varying proportions of flaked metals. These are harder than non-metallic pads, more fade-resistant and longer lasting, but at the cost of increased wear to the rotor/drum which then must be replaced sooner. They also require more actuating force than non-metallic pads in order to generate braking torque.
Fully metallic materials - these pads are used only in racing vehicles, and are composed of sintered steel without any synthetic additives. They are very long-lasting, but require more force to slow a vehicle while wearing off the rotors faster. They also tend to be very loud.
Ceramic materials - Composed of clay and porcelain bonded to copper flakes and filaments, these are a good compromise between the durability of the metal pads, grip and fade resistance of the synthetic variety. Their principal drawback, however, is that unlike the previous three types, despite the presence of the copper (which has a high thermal conductivity), ceramic pads generally do not dissipate heat well, which can eventually cause the pads or other components of the braking system to warp.However, because the ceramic materials causes the braking sound to be elevated beyond that of human hearing, they are exceptionally quiet.
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First of all, domestically produced electric film production machinery is based on the transformation of Korean companies on the basis of printing machinery. The basic equipment sold in China is second-hand refurbished machinery. While purchasing machinery, the contract is subject to technical training requirements. Produced a qualified electric film, but this pass is still not well defined! Therefore, many of the electrothermal films that lead to production are of unqualified quality. This is well understood:
1, South Koreans also want to do wholesale, this market they will not lose, just to renovate the machinery that will soon be scrapped. There are many reservations on the delivery of technology!
2. Some domestic companies, due to high investment, have reduced input from their own materials.
(1) Surface PET material, its own material as a recycled material, does not apply the best material. The result can be thought to be that the leakage current is too high and the high temperature resistance is limited. Some of the franchisees have even started to trip after construction and cannot accept it.
(2) The high-temperature adhesive cannot reach the drum due to the high temperature, and the lamination technology is not a good factor to grasp.
(3) In the selection of ink, there is no understanding of the core elements of electrothermal film, and then the main cause of non-uniform heating with less investment, carbon film printing technology, but off, resulting in uneven finished product printing, showing a very dense pinhole. This is a well-defined and visually significant one.
3, irresponsible attitude, many companies do not have actual construction experience, construction changes and requirements in various environments, on-site coordination can not give support. This is deadly for any construction company!
In addition to imported products, we all saw potential markets. As a result, the brands were mixed. Many so-called well-known brands were made by speculation. The actual product data was not ideal, and even a test room in the heating season could not pass. After 2-3 years, it will no longer heat, and it will decay badly. The data has just reached the National Standardization Committee of the Ministry of Construction’s Floor Heating Committee “Low-temperature Radiant Electric Heating Heating Standardâ€. So data and insurance are the key. Many companies' products are not tested by the state, and many of them use other people's test reports.
1, many Korean brand manufacturers, there is no factory in Korea, just a brand.
2. As a result of the brand phenomenon of the ocean and other industries, there is a South Korean brand that has been closed for many years, and no electric film was produced before it failed to close. What is ridiculous is that there are actually three electric heating films of the same brand in three cities in the country. It is not yet. How can such a company provide protection?
3. In Korea, 3-5 homes are produced with stable products. Mature electric membranes require many years of technical mastery and continuous R&D to shape, but now the domestic market is hot, leading to more people temporarily investing in electric film. Manufacturers have seized the domestic psychological like foreign brands. In fact, the quality of electric film failed.
4. Because the manufacturers who have increased sharply have been constantly testing, they all rushed into the domestic market at the low price of tens of thousands of flat or tens of thousands of unqualified products. The cost of processing chemical products in Korea is high, so it is low. The price is sold to domestic countries that only look at the interests and low-cost sales are made, indicating that it is waste products.
5. These small-scale commercial enterprises do not have any construction experience and experience. In addition to the cheapness of products, when your business is carried out, the relevant project guidance and training cannot be given during the process of the project.
Then, as an investor or consumer user, how do we choose a good electric film? Make sure the test report of the product is true and not applied.
1. The product has national testing in China. One concern is leakage current and the other is conversion efficiency of electrothermal radiation. Here I want to clarify the meaning.
(1) Leakage current (national standard qualified product is ≤0.25%, this data requirement is already terrible and many products are not yet available): Any electronic product has a slight leakage current, industry and country are allowed, but If it is too high, it will directly affect the use after installation, leading to no acceptance. Leakage current will be higher when the quality of the material is not good enough, especially after a humid environment. Therefore, the data you want to see must have data on the increase in leakage current after a humid environment.
(2) Electrothermal radiation conversion efficiency (National standard qualified product is ≥55%: The solution is how much heat is emitted by one degree of electricity, so the higher the percentage, the same design power, the same use environment based on which you can be more energy-efficient, have to be here To say something, many people in the industry did not understand it, and each time they asked how much the conversion efficiency of electrothermal radiation is, 99% is the utilization efficiency of electrothermal conversion, not the data of the radiation heat output. Basically, this data can be achieved, because when the heating without water or oil and other intermediate medium heating and then conduct heat, so it saves energy.
The above descriptions are all external factors, sensory information obtained, and now I'm talking about our own hands-on violence test, which is also the basic means to find qualified products.
1, high temperature test, with two pieces of more than 3 cm extruded board, put the good electric film sandwiched in the middle, four weeks after the heat is tightly heated to 120 degrees or more, take a look at the electric film changes, can be single, multiple We look at heating and can continue heating. (Can be detected with a laser gun)
2, folding test: This test can directly detect the basic life and quality of electrothermal film. At the same time of energization, it is repeatedly crimped at the connection between the conductive silver paste and the heating ink of the electrothermal film, and it must be compacted with a finger and then refolded. After five times, the electrothermal film penetrated directly by the fire will last for five years. And after your clips are pressed together, it is very likely that the direct fire will lead to your failure of moisture protection. The direct result is that it will lead to leakage and cannot be closed. In our test, many electric heating films had the phenomenon of breakdown of all the heating bars at one time. This kind of film is definitely problematic. The good electric film can be folded more than tens of times. Including the electric heating film heating ink, you can use the foot pressed to fold in the test. (Be careful to be hot or get an electric shock during the test)
If you have understood the above description, then you can certainly choose a good electric film products! In combination with the corresponding construction technology, there will be no tripping and other phenomena, our company's largest area of ​​a single room heating film heating environment is 800 square meters, the floor height of 3 meters 8, the design power of 112,000 watts, from the installation is completed to use, only A test is performed when installing the temperature control. No problems have occurred so far, or tripping has occurred. In addition to the product itself, construction details and techniques are also critical.
Yingying Electric Heating Business Department, Product Investment, Electrothermal Membrane Engineering, Electric Heating Construction, Electric Heating Material Wholesale, Non-Enterprise Product, Yingying People will also provide free technical exchange, guidance and training, and expect more warming people to better development of.
British electric film -YOHO, data: national standards for leakage current ≤ 0.25%, British electric film 0.016%; lower than the national limit standard 15 times; electric film electric heat radiation conversion efficiency of the national standard qualified products for the ≥ 55%, the British The electrothermal film-electrothermal radiation conversion efficiency of 78% is far ahead in the strip film market, and it is more energy-saving by more than 15% under the same power and use environment.
How to choose a good electric film - electric film quality self-test
In the market with many electric film brands, as consumers or entrepreneurs who want to invest in the industry, they are risking to read advertisements to understand the basic information of some electric films! There are dozens of foreign brands on the market, and there are more than a dozen domestic brands! How to choose a good electric film? We first understand this industry.