Under the test of film covering strength of the mo

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Post press technology: Test of film strength (Part 2)

the curve shows the change of peeling force. People say that the effective test range is compared with the same period last year (that is, the range involved in data calculation). Although the test data of the first 25mm and the last 10mm can be displayed, they do not participate in the calculation of the last test results

(3) easy to operate and use. The whole machine adopts the high-tech of electromechanical integration, and is equipped with an easy to control operation panel; LCD large screen liquid crystal display; The operation process is simple and easy to master; The test results can be displayed alternately on the screen or printed directly; It has RS232 interface, which can be connected with the computer to further process the data (it should be equipped with relevant software). These characteristics are not only suitable for general technicians to conduct simple tests, but also suitable for researchers to conduct in-depth research

to sum up, the "XLW series" intelligent electronic tensile testing machine can not only meet the provisions of relevant standards, but also meet some special requirements for the determination of composite strength of coated products. It is an ideal testing equipment

3.3 test plan

according to the relevant provisions of the referenced national standards, combined with the performance and characteristics of the selected test equipment, after repeated tests, modifications and improvements, the following test plan is designed to test the composite strength of film coated products

3.3.1 specification of sample size

in order to ensure that the effective peel length is 120mm, according to the relevant provisions of the reference standard and the actual situation of the test equipment, the sample size width in the test is 15mm and the length is at least 2O5mm (the sample length can be appropriately extended to facilitate the experimental operation)

3.3.2 preparation and treatment of samples

remove 50mm from both ends of the width direction of the ring stiffness test sample, cut 6 longitudinal and transverse samples evenly along the width direction of the sample, and the composite direction during coating is longitudinal. Strip the paper base and plastic film about 50mm in advance along the length of the sample, and the stripped part is required to have no obvious damage. In this way, the sample can meet the requirements of effective stripping length of 12mm in the stripping process (plus 25mm at the beginning of stripping without data statistics and 1omm before the completion of stripping, and the total stripping length or composite length is 155mm)

3.3.3 regulation of temperature and humidity of samples and test environment

the treated samples should be placed in an environment with a temperature of 23 ° C ± 2 ° C and a relative humidity of 45%-55% for more than 4h, and the tests should be carried out in the above environment as far as possible

3.3.4 provisions of test speed

refer to the provisions of relevant standards and specify the test speed as (300 ± 50) mm/min according to the performance of the test equipment

3.3.5 test process

(1) equipment preparation

place the equipment on a stable workbench and adjust it to the level; When the power is turned on, the equipment automatically enters the prompt screen, press the "monitoring" key to enter the main display screen, and then press the "monitoring" key to select the experimental items

(2 the lock body and stop (or lock catch) shall be able to withstand a transverse load of 4440n at the semi locking position; In the fully locked position, it should be able to withstand a transverse load of 8890n and should not be disengaged) it is more reasonable to use a simple experimental setting; About the selection of experimental items and the setting of parameters for research-oriented users who care about the details of experiments

the composite strength test of coated products is carried out under the experimental item of "18O peel". According to the test requirements, set various parameters, such as: length of 12mm (refers to the length of the effective test range), width of 15mm, speed of 25omm/min, etc

(3) adjust the collet position

connect the "experiment" key, the sample number is displayed as "1", and enter the standby state. Press the "down", "slightly up" and "stop" keys respectively to adjust the position of the collet so that the distance between the upper and lower collets is about 90mm (less than the distance between the paper base and both ends of the plastic film after manual pre stripping of the sample, which is 1o0mm to ensure that the sample can be fixed between the two collets)

(4) fix the sample

fix one end of the paper base and one end of the plastic film of the pre stripped sample between the upper and lower collets respectively, and make them in the same vertical plane, so as to ensure that the tension applied during stripping is in the same straight line

(5) formal test

press the "experiment" key, and the equipment will automatically peel the sample; After stripping, the equipment will stop automatically, and the upper collet will automatically return to the initial position; Press the "number plus" key, and the sample number is increased to "2" to test the second sample; The test of the sample in article 3-6 can also be completed

(6) return to the main display screen to display, count and print the test results

under this test item, select the sample number, and print the test results of each sample and the whole process tracking curve respectively (Statistics of the test results of 6 samples at most); Select number "7" to print group statistical reports (given in list form)

4. Significance of designing this test plan

this plan is designed for the composite strength test of film coated products, referring to the relevant national standards, and considering the selection of test equipment and some specific problems in the actual operation process. Through repeated tests, modifications and improvements, the scheme is practical and operable, which is helpful for actual production, testing and research. The scheme has the following significance:

(1) it provides a feasible test method for the composite strength of coated products, and at the same time, it provides a new idea for the quantification of composite strength (peel strength), a more important index in the quality inspection and evaluation system of coated products

(2) accurate and reliable data can be obtained through more scientific detection to guide the actual production. As mentioned above, the film coating process is a post press surface finishing process. Before the film coating, printing and other processing processes have been carried out. Therefore, the quality of the film coated products is affected not only by the parameters of the film coating process, but also by the previous process. Using this test scheme, the parameters of the film covering process and the pre process can be changed regularly, and then the composite strength of its products can be tested to obtain a set of test data. After scientific analysis, the rules can be found to guide the actual production

(3) promote the construction of relevant national standards. In the existing national standards, the quality inspection methods of film covered products only require visual inspection based on experience, while in the actual operation process, only empirical methods such as "looking", "folding" and "rubbing" are used for quality evaluation. This method is difficult to achieve the consistency of test standards, and it is also lack of persuasion. Through the design and practical application of the test scheme, it can play the role of "throwing bricks and attracting jade", provide a new idea for relevant personnel, and do some basic work for the construction of relevant standards

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