The action of this instrument is based on the principle of mirror reading of the bending of a steel plate under tension.
On the instrument, the stretching curve at constant speed can be obtained, and the tensile strength, fracture length, strain work (based on the stretching curve), and spring degree (for the strain in forward rotation and reverse rotation) can be measured. It can also measure the relationship between deformation and time (the reduction of tension in the case of constant deformation), and check the relaxation process. (Related Instruments: Tensile Tester)
In this way, some basic mechanical properties of the paint film can be measured quite accurately on the instrument, and the test can also be carried out at various strain rates.
The measurement of the tensile strength and the measurement of the secondary length at break were carried out as follows. Fix the paint film to be tested between clamps 1 and 2 of the apparatus (Fig. 140). Start the motor (through the pulley 3) to drive the graduated goniometer (nnM6) 4, while the lower clip 2 is retracted downward, and the sample (paint film) is elongated until it breaks. The pulling force is shown on the side scale 5 by means of an indicator 6, 1 which can then be read more accurately on the goniometer scale. Its tension can be indicated by the mirror reading of the position change of the mirror connected to the upper center 1.
Mirror is enclosed within on the shaft rod 7 that is fixed on the steel plate 8 that can deflect. The instrument is equipped with a set of steel plates for different loads (from 5 kg to 10 kg). When the steel plate is deflected, the moving scale is reflected in the mirror; the lens barrel of the focal point can be doubled for observation.
The steel plate must be calibrated in advance; various loads are hung on the upper clamp l, and the position of the scale marked in the mirror must be recorded each time, and then the box is made into a curve, and the division of the scale is converted into grams in the curve.
