The standard "Volvo STD 423-0012 Adhesion - Cross-cut test - Paints and enamels", developed by the Volvo car company, describes a method for testing adhesion between different paint coatings or between a coating and a substrate. In terms of its technical content, this standard complies with the standard "ISO 2409 Paints and varnishes - Cross-cut test" and the standard "ASTM D3359-23 Standard test methods for adhesion rating by tape test".
The samples used in the tests are painted test panels of the relevant substrate or test object. Painted test objects must be conditioned in accordance with STD 1021,1 before testing.
The main equipment used in these tests includes:
When testing, the thickness of the paint coating is determined at the location where the lattice pattern will be made. Depending on the coating thickness, the cuts must comply with the table given in the standard.
Before cutting, the cutting tool edges should be examined first. If the cutting tool thickness is worn down to 0,1 mm or if small edge pieces are missing on the multi-blade cutting tool or guide edges, the cutting tool should be replaced. First, six parallel cuts are made with the cutting tool to obtain a lattice pattern. Then, six more cuts are made overlapping the original cuts and at 90 degrees to them. In this way, a cross-cut area of 25 squares is obtained. The cuts should be made at a uniform speed of 20-50 mm/s.
The cuts should penetrate to the surface of the substrate. For organic substrates, avoid cutting the substrate. However, when using manual cutting tools, it can be very difficult to avoid cutting the substrate. If the test object has a curvature, two cuts in the same line may be required to create a 25-square grid with a multi-blade cutting tool (manual cutting).
Manual cutting is recommended when testing plastic parts and metal parts with curvature. A lamp connected to the cutting tool and test panel can be used to obtain the correct cutting depth when working with metallic substrates and using mechanical cutting equipment.
The edge of the panel is scraped to provide electrical contact between the auxiliary electrode and the metal substrate. Contact is made when the cutting tool reaches the substrate and the lamp lights. The correct depth is achieved when the pressure applied to the cutting tool is adjusted so that the lamp lights. For another cutting tool, the depth of cut should be checked with a magnifying glass.
All loose material should be removed with a brush. The lattice pattern should then be covered with tape. A fingernail or brush handle should be pressed onto the tape to ensure proper tape adhesion. The tape is quickly removed using a little extra force. The angle of pull between the test object and the tape should be approximately 60 degrees. The paint is now ready for evaluation. Additional testing is recommended when borderline results are found.
The cross-sectional area is evaluated and graded. A 2-6x magnification magnifier is used for evaluation. The grading scale is from 0 to 5 according to the ISO standard.
Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “Volvo STD 423-0012 Adhesion - Cross-cut test - Paints and enamels” standard with its trained and expert staff and advanced technological equipment.
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