Plastic film friction coefficient test method - Database & Sql Blog Articles

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In the production of film and plastic packaging bags, the friction coefficient of plastic film is an important index. On the one hand, it together with the anti-blocking property of the film becomes the quantitative evaluation index of the opening property of plastic film, on the other hand, it can be used as the running speed of automatic packaging machine. One of the reference data for tension adjustment and film running wear. With the increasing automation of modern production equipment, higher requirements are placed on the friction coefficient of the film. Accurate determination of the friction coefficient of the plastic film has become one of the necessary items for the film and flexible packaging manufacturers.
At present, there are two main methods for measuring the friction coefficient in domestic film production and use manufacturers. One purchases a separate friction coefficient meter, and the other is a multi-purpose tensile testing machine, which increases the friction coefficient of a special device. In the after-sales service, we found that some flexible packaging manufacturers have an intuitive understanding of the former, but they are quite vocal because they are not only expensive, but also have low utilization rate. In addition, they are also required as a single device (such as adequate testing sites, personnel, maintenance and repair). Wait). Is there a simple and economical way to solve this? Here, we focus on the latter that is not known to the majority of flexible packaging manufacturers.

In fact, the national standards that are currently in widespread use, as early as May 1, 1988, were approved by the former Ministry of Light Industry of the People's Republic of China for the determination of the friction coefficient of GB 10006-88 plastic film and sheet. method. The latter, as a typical device for multi-purpose use, has been used in plastic raw materials factories such as Yanshan Petrochemical. 1—load sensor of force measuring system; 2—spring that adjusts elastic coefficient; 3—horizontal test bench; 4—slider; 5—sample on horizontal test bench

The test of the friction coefficient in GB 10006-88 Method for Measuring the Friction Coefficient of Plastic Film and Sheet, that is, the two test surfaces are laid flat together, and the two surfaces are relatively moved under a certain contact pressure to record the required force. Among them, the above is the principle device of the friction coefficient meter, and the following is the additional device in the multi-purpose of the tensile testing machine. The bottom is the friction level test rig (made of non-magnetic material, generally stainless steel), which needs to be fixed at the lower end of the tensile testing machine. The horizontal pulling force of the upper slider is converted into the vertical of the tensile machine through the steel wire through the pulley. To pull the force, fix the other end of the wire to the upper clamp of the tension machine by adjusting the spring.

Static friction: The maximum resistance of the two contact surfaces at the onset of relative movement, expressed in Fs.

Dynamic friction: The resistance when two contact surfaces move relative to each other at a certain speed, expressed as Fd.

Normal force: The force applied perpendicularly to the two contact surfaces, expressed as Fp, typically 1.96 0.02 N.

Static friction coefficient: The ratio of static friction to normal force, expressed in μs.

Dynamic friction coefficient: the ratio of dynamic friction to normal force, expressed in μd.

It can be seen that the above two figures have the same principle and structure, except that the latter adds a pulley and transfers the direction of the tension to 900, so that the device can be used on the tensile testing machine, so that no equipment is added in the laboratory. The determination of the coefficient of friction is achieved.

The tension machine is equipped with the above devices, and the following points should be noted.

1. Consider the tension sensor, because the general friction coefficient of the film only needs a few Newtons of tension. If a tensile tester equipped with a 200 or 100 Newton sensor is selected, the error is too large. A 10 Newton sensor should be considered for the friction coefficient test.

2. The lower end of the tension machine needs to be reserved to fix the friction test board to ensure that the left side of the pulley on the test board is in the middle of the tension machine and keep it level.

3. The tensile machine should have corresponding computer processing software.

By using the above method, it is only necessary to increase the cost of the existing tensile testing machine to achieve multi-purpose, which is economical, and also reduces the necessary cost for a single device. A practical method for determining the coefficient of friction in the construction of flexible packaging laboratories.