1. Scope and description
Adhesion is the fastness of the paint film to the substrate. This method is to fix the template on a movable platform at the front and rear. When the platform moves, the stylus moving in a circle can cut through the paint film, and can draw overlapping circular rolling lines. The integrity rating of the paint film, expressed in grades.
2. Instruments and Materials
(1) Adhesion Tester as shown in Figure 1-4-26. The screw pitch of the instrument test bench is 1.5mm, and its rotation is synchronized with the rotating needle; the rotating needle adopts Sanwu brand stylus, and the no-load pressure is 200g; weights can be placed on the load plate, and its quality is 100g, 200g, 500g, 1000g ;The turning radius of the rotary needle is adjustable, and the standard turning radius is 5. 25mm.
(2) Quadruple magnifying glass.
(3) paintbrush width 25 ~ 35mm.
3. Measurement method
(1) Check the needle of the adhesion Tester before testing, if it is not sharp, it should be replaced. Lift half of the nut, pull out the test bench, and the needle can be replaced.
(2) Check whether the scratches are consistent with the standard radius of gyration, if not, adjust the radius of gyration. The adjustment method is to loosen the bolts behind the pin plate and the adjusting bolts for the radius of gyration. After moving the pin plate appropriately, tighten the above bolts in turn. Compare the scratches with the standard circular rolling line diagram, and adjust until the standard radius of gyration is 5.25. The round rolling line of mm is the same. See Figure 1-4-27 for the relevant components of the instrument. .
(3) When measuring, put the painted surface of the sample on the test bench, tighten the adjusting bolt to fix the sample, move the lifting rod backward, so that the tip of the rotating needle touches the paint film, and shake the handle evenly in a clockwise direction, Rotating speed is advisable with 80～100r/min,
1-loading plate; 2-lifting rod; 3-card needle plate; 4-rotation radius adjusting bolt; 5-fixed sample adjusting bolt; 6-test bench; 7-half nut; 8-fixed sample adjusting bolt; Test bench screw; 10-adjusting bolt; 11-handle
The standard length of the round rolling line scratch is (7. 5 ± 0. 5) cm.
(4) After scratching, move the elevating bar forward to lift up the clamp plate, loosen the relevant bolts that fix the sample plate, take out the sample plate, remove the paint chips on the scratches with a paint brush, check the scratches with a four-fold magnifying glass and remove them. rating.
Note: If the scratches do not expose the bottom plate, weights should be added as appropriate.
4. Result representation
Take the upper side of the scratches on the model as the inspection target, and mark seven parts 1, 2, 3, 4, 5, 6, and 7 in sequence. Correspondingly divided into seven levels, as shown in Figure 1-4-28. Check the completeness of the paint film of each part in order. If more than 70% of the grids of a certain part are intact, the part is considered to be intact, otherwise, it should be considered damaged.
The adhesion of the paint film is indicated by the lowest grade of the intact paint film. The results are based on the same grades of at least two samples. The first grade is very good, and the seventh grade is the worst.
5. Reference standard
National Standard GB/T 1720 "Determination of Paint Film Adhesion".
Figure 1-4-28 Schematic diagram of grades of scratching adhesion
