Application of the hottest ultrasonic technology i

Application of ultrasonic technology on corrugated wire

"[i cold" corrugated wire can reduce the processing process of corrugated board, reduce investment costs and operation and maintenance costs, and reduce energy consumption. However, despite the "cold" Tile wire has many advantages mentioned above, but after more than 40 years of research, it still failed to achieve convincing results. So, can the ultrasonic welding technology, which has been used for plastic films, some non-woven materials and man-made fiber textiles for a long time, be used to produce corrugated board? BHS has been committed to investing in the development of corrugated board production lines that can produce wider paperboard and faster processing speed, and is very concerned about its market development potential. Therefore, BHS formed a research group to research and develop this new technology. The members of the group are members of university research institutes and technical experts in the corrugated board industry. [/i the team has been straight to the research topic since the beginning of the research - the bonding of corrugated core paper and face paper. It is assumed that the bonding of corrugated core paper and face paper within one minute on the corrugated line with a production speed of 300 meters/minute can also be used to change the performance of other elastic elements and friction mechanisms. This means that the influence of ultrasonic jet head (also known as ultrasonic contact) on the paper is less than 0.2 milliseconds (0.0002 seconds) 。 0.2 milliseconds is almost the same as the action time of the pressure roller on the traditional single-sided machine, although the production process of the traditional single-sided machine includes the preheating process. One of the goals of using ultrasonic bonding technology is to eliminate the influence of residual moisture (the paste used by current single-sided machines in the production of corrugated board contains moisture), and moisture often affects the flatness of the board. Compared with the traditional corrugated board processing process, ultrasonic technology has the following advantages:

· no need to use paste, so as to eliminate the influence of moisture on the cardboard processing process

· no need to preheat the corrugated roller

· reduce the occurrence of cardboard warpage

· there will be no single-sided paperboard without bonding when the machine is restarted

ultrasonic equipment

for practical application, This research project is limited to the use of longitudinal ultrasonic contact or roller ultrasonic contact

in actual production, ultrasonic wave is generated through bonding unit. The bonding unit comprises an ultrasonic generator, a processor, a supercharger and an ultrasonic contact. The ultrasonic generator generates ultrasonic waves, and continuously monitors and controls the amplitude and wavelength of ultrasonic waves through the processor (because the uncontrolled increase of amplitude will seriously damage the whole system). The supercharger expands the amplitude at the ultrasonic contact to obtain the amplitude required for production. At the end of the ultrasonic contact, that is, the end of the system, frequency modulation (such as the role of the supercharger) must be carried out to make the wavelength resonate. Ti-3av produced from titanium is usually used to achieve the highest ultrasonic amplitude. Ultrasonic resonance is mechanical, which must be directly transmitted to the material through pressure and bonded on the supporting anvil pad. In this case, the anvil pad is the rotating upper corrugating roller

base paper

base paper is composed of cellulose and is not thermoplastic. Many plastic materials suitable for ultrasonic bonding technology have the bonding effect due to their inherent thermoplastic and the heating of fixed positions. The team conducted a study to establish an adhesive relationship between two sheets of paper

researchers first tested different paper under different production parameters, and then removed the acetyl group with strong alkali under heating conditions. Using a wide range of soluble chitin (chitosan) sheet levels of 10 points, they determined its adaptability to ultrasonic bonding technology, and understood and clarified the bonding mechanism. The researchers also went to the paper research institute to produce some samples as required, and analyzed the results of ultrasonic bonding test. Pulp containing certain fibers is thus produced (bleached and unbleached pine pulp and mechanical wood pulp). These include 100% mechanical pulp, 50% bleached and 50% mixed mechanical pulp

then the test on the sample. The measurement conditions include loading pressure, exposure time and vibration amplitude - including humidification, non humidification or paste - the main purpose is to determine which parameters have an impact on paperboard production. The preliminary results show that the proper addition of paste and moisture is very important to obtain the specified bonding strength. The ideal bonding effect cannot be achieved only by ultrasonic technology

in the second series of tests, four pastes with different dilution concentrations were applied to the paper surface, and then ultrasonic bonding was carried out under specific conditions. The adhesion strength in each case is measured by anti stripping test, and the results are as follows:

· on the paperboard without any wetting or without any paste, even if the paperboard is rich in lignin, it is impossible to achieve the adhesion effect by completely using ultrasonic technology

· cardboard containing a certain amount of moisture and paste can be bonded by ultrasonic technology. The bonding strength depends on the situation

ordinary core paper and face paper test

the objects of the third group of series tests are ordinary core paper and face paper. The test results have reference value

in the primary testing stage, a variety of ultrasonic application time, static bonding pressure and vibration amplitude are used to limit the processing parameters. The next test series uses dry paperboard (usually with natural moisture content of 5%-8%), and the corrugated type is c-corrugated, and then add moisture on these papers. More than 550 cardboard samples were used for ultrasonic testing. TAPPI T82 is used to measure the adhesive strength of paperboard, and the accuracy remains unchanged 1 standard (adhesive strength measurement standard)

the "dry" test (i.e. no humidification of the paperboard) was carried out first, and the result was either poor bonding strength or burning of the paperboard. The test results show that the longer the cardboard is exposed to ultrasound, the greater the contact pressure is, and the bonding strength will be improved accordingly. The best adhesive strength obtained is 26% of the traditional paste dosage, and the exposure time is 0.1 seconds. The adhesive strength produced in this way is 100 times higher than that under traditional production conditions

"wet" test (i.e. humidifying paperboard) is much more complex. Since the exposure time is 0.06 seconds, the use of the equipment is limited. The test results show that the shorter the exposure time of Paperboard under ultrasonic, the greater the contact pressure, and the higher the bonding strength. Reducing the amplitude will only have a small impact on the bonding strength. Through the above tests, it is not difficult to draw the following conclusions:

· for ordinary base paper, humidity is sufficient