How to solve the two major problems affecting the preparation quality of glass fiber sizing agent?
China's high-performance fiberglass and carbon fiber products have a gap in performance from international brands. The quality of samples developed by researchers in the laboratory may be very high. Some of them may even exceed foreign products, but small-scale trials and mid-scale trials will not result in comparison. With good economic benefits, we must invest in industrialization and automation. Surface post-treatment directly affects the performance of glass fiber products. The infiltration agent is prepared from a variety of raw materials. Automatic metering equipment manufactured according to the highest national standards currently implemented can guarantee the preparation requirements of glass fiber infiltrant. Totally impossible! The following specific analysis of the reasons.
1. The measurement equipment used for the preparation of glass fiber sizing agent is quite different from other industries. Any measurement equipment has actual error, that is, there is a difference between the data displayed by the equipment meter and the actual actual data. There are errors, there are errors in the sensor, there are errors in the control of the operation, these errors are the integrated error of this equipment, which is the so-called equipment measurement accuracy. Measurement accuracy has the difference between static accuracy and dynamic measurement accuracy. In actual production, only the dynamic measurement accuracy meets the standard, so as to ensure the accuracy of raw material addition.
The metering equipment used for the preparation of glass fiber infiltrants is quite different from other industries. The simple measurement method is to add a plurality of raw materials in order, adding only a single medium at a time, and the accuracy of the selected measurement equipment and the measurement accuracy of the process requirements can be the same. The emulsion metering process is a process in which two media enter the same metering device at the same time. Two metering devices must work together to calculate the exact amount of raw materials to be added. Moreover, the selection accuracy of the two metering devices must be higher than the process requirements. A grade, see below for an example.
The special properties of polymer emulsions with high viscosity, easy adhesion to wall, and easy skinning determine the special process for the preparation of glass fiber sizing agents. To prevent emulsion metering equipment and pipe plugging damage, it is necessary to use water before the emulsion is added. Flush the adding equipment and piping, and the weight data recorded by the electronic weighing scale at this time is the sum of the mixture of the emulsion and the water, ie, the weight of the emulsion = the weight of the mixture of the emulsion and the water - the weight of the water. Glass fiber sizing agent preparation process requirements: emulsion raw material measurement accuracy of 0.1%, although the measurement accuracy of deionized water 1%, in order to accurately calculate the amount of emulsion raw materials, first of all to accurately measure the exact weight of water in the mixture, or can not be converted The actual amount of emulsion material added.
If the mixture of measuring emulsion and water is A scale, and the measuring and washing water is B scale, the amount of emulsion added shall be 4000g. According to 0.1% technical requirement, the emulsion measurement accuracy shall be controlled between 3996g and 4004g.
The first analysis is that when the emulsion metering and equipment flushing are completed, the A weighing instrument displays 6000g, the actual error of the A scale is +0.1% (positive maximum error), the actual weight of the mixed liquid can be calculated as 6006g; the B weighing instrument shows 2000g, the actual of the B scale The error is -0.1% (minimum negative error), and the actual wash water weight is calculated to be 1998g. The actual amount of emulsion added = 6006g-1998g = 4008g, 2 times excess. (The 0.1% maximum allowable error of 4000g is 4g.) The actual error of any automatic metering equipment is random, and cannot be artificially controlled. At this time, the data recorded by the system, such as curves, production reports, etc., are all displayed on the meter. The data, in brief, computer-recorded data are all false, all operations are carried out as required, that is, the reason for the unsatisfactory formulation of the glass fiber sizing agent cannot be found. If the two scales A and B are selected to have a dynamic weighing accuracy of 0.05%, the actual amount of emulsion added is 6003g-1999g=4004g, which fully meets the measurement accuracy required by the process. This is why the metering addition of the emulsion, the measurement accuracy of the two metering devices must be higher than the one required by the measurement accuracy of the process. The actual errors of the two scales are both positive and negative offsets, and they are also overlapped in the same direction. However, the overlap of two 0.05% maximum actual errors in the same direction will never exceed 0.1%. This is obviously a simple matter of arithmetic.
Similarly, when the actual error of the A scale is -0.1% (minimum negative error), and the actual error of the B scale is +0.1% (the maximum forward error), the actual amount of emulsion added = 5994g-2002g = 3992g. Very bad.
Second, the raw material added precision control requirements higher Glass fiber sizing agent production is more difficult, summed up in the following points:
1. There are many kinds of raw materials and there is a big difference in the amount of each component, ranging from a few hundred grams to hundreds of kilograms. For example, in some formulations, the amount of silane added is 0.25Kg/ton, which belongs to trace addition, while the amount of some emulsions added is 160Kg/ton, a difference of several hundred times. It is required to add equipment with high precision and large flow.
2. The polymer emulsion has high viscosity, easy to adhere to the wall, easy to crust, to ensure the measurement accuracy is high, but also to avoid the emulsion metering equipment and pipelines do not crust, do not plug damage filling equipment, measuring equipment and conveying pipe The road is not adhered to the wall, and the weighing scale discharges to the preparation tank completely, cleanly and thoroughly. Otherwise, the significance of adding high-precision metering in the previous process will be lost.
Beijing Liede Linde Institute of Automation Equipment, after many years of research, using a number of high-tech, successfully developed glass fiber infiltrant preparation automated production line, a good solution to the difficult problems of the glass fiber infiltration agent in the automated production. Breaking the monopoly of high-standard automated production equipment from foreign manufacturers in this field.
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