Special processing is also known as non-traditional or unconventional processing Non-traditional（conventional）Machining， Abbreviation: NTM or NCM. In special processing, ultrasonic machining (USM), also known as ultrasonic machining, is particularly suitable for effective processing of brittle and hard materials, both conductive and non-conductive.
At present, most people know about ultrasonic cleaning, but during the cleaning process, burrs on the surface of the workpiece, blind holes inside, intersecting holes, and some places that are difficult to operate manually cannot be removed. Why is this? Because the important indicator that determines the ultrasonic ability is the power density (W/cm2) of the ultrasonic waves. Generally, the power density of ultrasonic cleaning is 0.5-0.8 (W/cm2), and in order to remove burrs with ultrasonic waves, the power density of the ultrasonic waves must reach 2? Above (W/cm2). (Due to the power limitation of the transducer, the current power density of ultrasound has reached 4W/cm2 in practical applications, and theoretically, this power can be increased.)
The basic principle of ultrasonic deburring is that when the ultrasonic energy generated by ultrasonic waves acts on a liquid that is vibrating in a sparse state, it will tear into small cavities (i.e., the interior is vacuum). These cavities will generate instantaneous pressure of up to several hundred atmospheres when they rupture, and this phenomenon is called cavitation Ultrasonic deburring utilizes the instantaneous pressure of several hundred atmospheres generated by cavitation to remove burrs attached to metal.
In mechanical processing, deburring precision surfaces is not an easy task, and it is highly valued in the manufacturing industry of industrialized countries. The United States once conducted a survey of 400 factories, and more than 70% of them had staggering deburring costs, with a small portion accounting for 40% of production costs. Among these 400 factories, 80 factories have deburring costs that account for 10-20% of production costs. In the past decade, the annual cost of deburring in the United States has exceeded $3 billion, with some years reaching as high as $8 billion. Moreover, for high-precision components in aviation and aerospace equipment, the cost of deburring is almost the same as the total cost of other processes. In the fierce international competition, a considerable part of China's machinery industry products have failed due to surface quality issues of parts.
Nowadays, many people only talk about the running in period of the engine when talking about cars. In fact, this is not correct. The running in period of a car not only includes the running in of the engine, but also includes the running in of the gearbox, etc. The gearbox mainly involves the running in between gears, and its running in time is slightly longer than that of the engine. Generally, it requires a driving distance of 5000 kilometers, which means that after changing the oil twice according to the prescribed standards, the running in period is basically over. Someone is going to ask why high-end cars such as Mercedes Benz, BMW, etc. can be bought and run at a very fast speed or have a short break in period? The reason is that ultrasonic deburring technology is used in the production of automobiles produced abroad, mainly reflected in deburring the engine cylinder and piston rings to improve the running in between the inner wall and the piston, as well as deburring the transmission gears to improve the running in between the gears. In Japan, 25% of the staff at TOYOTA Automotive Company are directly or indirectly engaged in deburring and finishing work. According to statistics, more than 95% of the parts of a high-end small car need to be deburred. As major giants in the automotive manufacturing industry set their sights on China, we believe that ultrasonic deburring technology will become popular in the Chinese automotive manufacturing industry. Currently, Changan Ford Automobile Co., Ltd. Nanjing Company, jointly established by well-known Chinese and foreign automotive brands: Changan, Ford, and Mazda, has purchased several large ultrasonic deburring equipment. (To be precise, Changan Ford Mazda Nanjing Engine Factory purchased two sets of ultrasonic deburring equipment from Japan, mainly used for cleaning the casting sand of engine end caps. Some personnel from our company participated in the entire process of designing, manufacturing, debugging, and shipping the equipment.)
The steel mesh commonly used in SMT now is processed by laser on SUS304 plates with a thickness of 0.05-0.3mm. The processed steel mesh has burrs that are not visible to the naked eye. If these burrs are not removed completely, they will affect the drop of solder paste, resulting in insufficient tin content and affecting the quality of solder printing. The commonly used method for deburring now is electrochemical deburring, but with the increasing attention of the Chinese government to environmental protection, the problem of electrochemical deburring has also been exposed: new projects require stricter environmental inspections and audits, and large sites are needed to store the waste liquid left by electrochemistry. The use of ultrasonic waves can not only effectively remove burrs on steel mesh, but also meet China's current requirements for energy conservation and emission reduction due to the environmental friendliness of ultrasonic equipment and low demand for consumables. (The comparative photos of this case experiment have been displayed on the website and have been applied.)
Deburring the intersection holes of hydraulic valves and precision valves has always been a major issue. Previously, electrochemical deburring was commonly used, but with the increasing attention of the Chinese government to environmental issues and the difficulty of cathode production, some companies have already given up on this process; In the case of small valve types, some companies may choose thermal deburring - the principle of thermal deburring - thermal deburring method, which uses high temperature to remove burrs and burrs from parts. The processed parts are placed in a sealed combustion chamber, and combustible gases (natural gas/methane/hydrogen) and oxygen are filled into the chamber at a certain ratio and pressure. The combustible gas wraps around the inside and outside of the parts, as well as burrs and burrs. However, some processed parts cannot be oxidized on the surface, and the accuracy of thermal deburring is difficult to control. Currently, the selling price of a Chinese made thermal deburring equipment is around 480000 yuan. The valve specific ultrasonic deburring small equipment developed in cooperation with a foreign ultrasonic company has been well applied in a company in Kunshan. The hydraulic valves produced by this company are supplied to General Motors in the United States, and the main technology of the equipment has also been patented. In addition, the advantages of this specialized equipment are small and easy to operate, cheap price, small footprint, and it is very suitable for some small and medium-sized enterprises to use. (Ultrasonic deburring has a good effect on the small burrs of small valves. Currently, the commonly used valve machining holes in the market are above Φ 10, and the burrs generated are generally difficult. Such burrs need to be pre treated.)
DENSO Corporation, a Fortune Global 500 company, has established Denso (Changzhou) Fuel Injection System Co., Ltd. in Changzhou High tech Zone. Denso Corporation is a leading Japanese and the world's third-largest comprehensive manufacturer of automotive components, ranked 207th on the Fortune Global 500 list. It was originally a subsidiary of Toyota Group, and its products are supplied to many well-known car manufacturers such as Toyota, Honda, and Volkswagen, with an annual sales revenue of over 20 billion US dollars. Deburring the nozzle holes in fuel injection systems has always been a challenge, and electrochemical deburring is now commonly used. However, ultrasound also has a good solution to this problem. The spray effect has always been the ultimate standard for testing products. In the fuel injection system, the stroboscopic spray camera system was used to take the spray image of the nozzle for analysis. The results show that when there are burrs at the nozzle hole, not only the flow of the nozzle hole will be reduced, but more importantly, the spray shape of each nozzle will be changed, resulting in uneven fuel distribution in the fuel spray (Indeed, Denso Corporation has a great demand for ultrasound, and their main ultrasound supplier is HARADA from Japan.)
Some burrs may not be visible, but they do exist, and if not resolved properly, it can be a big problem! In the nozzle of agricultural spray, there is a key core component called spray sheet. If there is burr in the spray sheet, it will directly affect the effective drug receiving of crops, and affect the prevention and control of crop pests; A professional agricultural machinery manufacturer in China received an order to export to Japan. Japanese customers had high requirements. Their early processing methods could not effectively remove the burrs of the spray film, and the spray effect was not ideal. After using ultrasonic deburring equipment, they met the strict requirements of Japanese customers.
Below, we will share some new examples of ultrasound applications with you (the following applications are relatively new and not specialized in this field, so we will not provide an evaluation)
1. Ultrasonic acceleration for beer brewing
Generally, brewing beer takes about ten days to three weeks, mainly for fermentation and maturation of malt extract. Fermentation produces carbon dioxide in the liquid, but too much carbon dioxide can inhibit yeast growth, so it is necessary to find ways to reduce the carbon dioxide content in malt extract. The traditional method is to add soy flour, pea flour, malt flour and other particulate matter to malt extract, and wait for excessive carbon dioxide to slowly condense on these particulate matter and float up, then the bubbles and particulate matter can be removed together. However, for large breweries that produce millions of bottles of beer every day, this method is too time-consuming!
There is now an ultrasonic device that pressurizes malt extract through the device. The ultrasonic waves in the device will cause carbon dioxide to precipitate and form bubbles. When the bubbles float to the surface of the malt extract, they can be concentrated and removed. This device can remove approximately 40% of carbon dioxide per minute. It only takes a few minutes to remove excess carbon dioxide from the malt extract. In the future, such devices can also be applied in the production of drugs, food, and other carbonated beverages.
2. Ultrasonic therapy for the treatment of myocardial infarction and cerebral infarction
Seal the gas that can reflect ultrasonic waves inside the phospholipid membrane, create tiny bubble shapes, and add amino acid molecules to the surface of the bubbles, then inject the bubbles into blood vessels. Due to the characteristic of amino acid molecules adhering to blood clots, bubbles can "search" for blood clots after entering the body. By scanning the body with ultrasound, the location of the thrombus can be determined based on the different intensities of ultrasound waves reflected from various parts, as the bubbles attached to the thrombus contain gas that can reflect ultrasound waves. Subsequently, ultrasonic waves used for treatment are emitted to shatter the bubbles, and the force of the bubble explosion can destroy the thrombus.
3. Ultrasound therapy for cancer
Utilize ultrasound waves commonly used to observe fetal activity. Scanning the human body with this type of ultrasound is harmless. However, if the ultrasound beam is concentrated in one location, it will raise the temperature of the human tissue to 60 degrees Celsius, thereby killing the cells. The scientists at the research institute utilized the characteristic of ultrasound to penetrate deep into the patient's body and gradually remove the entire tumor. 240 elderly patients with prostate cancer were selected, who, due to their advanced age, are not suitable for prostate resection surgery, which is the conventional method for treating this type of cancer. After using ultrasound to remove the tumors of these patients, they were followed up for up to 5 years. A survey shows that 65% of patients have not had cancer cells in their bodies for 5 years, which is comparable to the success rate of prostate resection surgery. In addition, the proportion of postoperative urinary incontinence in these patients is only 8%. The proportion of patients who have had their prostate removed experiencing this side effect is as high as 80%.
4. Ultrasonic removal of blue-green algae
Cyanobacteria is a primitive and ancient prokaryotic organism that often reproduces in large numbers during summer. After decay and death, it forms a layer of blue-green and foul smelling foam on the water surface, known as "algal blooms". The recessed water bay around the vast the Taihu Lake Lake area is characterized by poor water mobility and eutrophication, which is a frequent occurrence area of cyanobacteria. Since the beginning of summer this year, the water level of the Taihu Lake Lake has been at a low level for 50 years. In addition to the continuous high temperature and little rain, the water in the Taihu Lake Lake is heavily eutrophicated. Many factors have led to the outbreak of cyanobacteria more than a month in advance, forming a natural disaster. In the afternoon of September 27, the newly revised Regulations on the Prevention and Control of Water Pollution in the Taihu Lake Lake in Jiangsu Province was reviewed and approved at the 32nd meeting of the Standing Committee of the 10th Provincial People's Congress, and will be implemented on June 5 next year. The restriction scope of laws and regulations extends to all administrative regions of Suzhou, Wuxi, Changzhou and Danyang, as well as the regions where rivers, lakes, reservoirs, channels and other water bodies that have an impact on the water quality of the Taihu Lake Lake are located in the administrative regions of Jurong City, Gaochun County and Lishui County. A series of new systems, including the water quality handover responsibility system, ecological compensation, regional approval restrictions, graded protection system, pollution declaration and registration, and pollution discharge permit system, reflect the strength of strict governance; The penalty amount has been increased from the current 100000 to 1 million.
The ultrasonic technology for removing blue-green algae mainly utilizes the cavitation and thermal effects of ultrasound to rupture blue-green algae cells and break chemical bonds in material molecules. Due to the presence of air pockets inside blue-green algae cells, the air pockets are broken under the cavitation effect, causing the blue-green algae cells to lose their ability to control floating. At the same time, various organic compounds inside the blue-green algae cells undergo thermal decomposition reactions with water under the thermal effect of ultrasound, resulting in thinning of the blue-green algae cell fluid and precipitation of cytoplasm. Through the experimental surface, it was found that by irradiating blue-green algae with ultrasound for 30 seconds, the breakage of algal filaments and the destruction of the structure and function of blue-green algae bile bodies interfered with the synthesis pathway of chlorophyll. In addition, ultrasound can also degrade other organic pollutants and algal toxins in water.