DecoRoccia Mechanical Testing
The quality of photo-imaged powder coating is determined by the characteristics hardness, elasticity and adhesion. The following tests are designed to examine one of two of these characteristics, as in the table below.
Decorative Imaging's finishes have passed all tests listed in the table above according to international standards where they exist. Below is a more detailed description of what these tests entail. In addition to proving the quality of our finishes, these tests also give you an idea of what is possible with our finishes.
Cupping Test: Measures the elasticity of the coating layer. To pass this test the surface finish must not crack or detach itself from the aluminium when deformed at least 5 millimetres above the surface (see diagram below).
Impact Test: Also measures the elasticity of the coating layer. When the aluminium is submitted to direct impact using 2’5 Nm of energy, it must not crack or detach itself from the metal.
Bending Test: Measures the elasticity of the coating layer. This test must not cause any cracking or detachment from the aluminium when a finished flat sheet is bent over a 5mm diameter cylindric mandrel.
Adhesion Test: This test determines the level of adhesion of the coating layer to the metal. The coating layer is subject to cross hatched incisions approximately 2mm apart. A piece of tape is applied over the incisions and then sharply removed. There must not be any detachment of the coating layer on the tape. Please note that Decorative Imaging performs this test on at least one random
piece of metal within each order processed to ensure our high quality standards are maintained.
Sawing/Countersinking/Drilling/Cutting Tests: These tests determine the resistance of the surface coating when subjected to such mechanical processes.
Buchholz Test: This test looks at the hardness of the surface coating. A 1mm incision is made in the coating layer which is then inspected under a microscope for any signs of delamination.
Polymerisation Test: This test examines how well the powder coating has cured in the oven. A cotton wad soaked in an MEK solution is wiped over the finished metal 30 times. If the coating layer becomes matt, soft and easily removable it has failed the test. Please note that Decorative Imaging performs this test on at least one random piece of metal within each order processed to ensure our high quality standards are maintained.