This standard is applicable to the determination of the thickness of paint films on the surface of wooden furniture and other wooden furniture parts. GB 4893.5-1985 Determination of the thickness of paint films on furniture surfaces GB4893.5-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of film thickness ofsurface coatings of furniture
Determination of film thickness ofsurface coatings of furnitureThis standard is applicable to the determination of the thickness of the surface coatings of wooden furniture and other wooden furniture parts. 1 Principle
UDC 684.4 : 667
GB 4893.5—85
A cone hole with a vertex angle of 120° is drilled on the paint film to be measured. The hole wall is imaged in a 40× measuring microscope. The generatrix length (paint film part) perpendicular to the main optical axis of the microscope is read in the microscope, and then the paint film thickness is calculated according to the functional relationship. 2 Instruments and equipment
2.1 Drilling device (see Appendix A).
2.2 Measuring microscope (see Appendix B).
2.3 Marking pen.
3 Sample
3.1 Specification is 250mm×200mm.
3.2 The sample should be stored for at least 10 days after coating and completely dry before testing. 3.3 The surface of the sample should be flat, and the paint film should be free of defects such as scratches and bubbles. 3.4 When sending samples, a test report should be attached, including the name of the paint, a brief coating process, production time, etc. Test conditions
The test room temperature is 20±2℃, and the relative humidity is 60%~70%. 5 Test steps
5.1 Take three test points for each sample, one of which is at the center of the sample, and the other two are at a position not less than 50mm from the edge on the diagonal line.
Use a marker (2.3) to apply to the test points.
5.8 Aim the drill bit of the drilling device (2.1) at the test point, turn the thumb wheel lightly and steadily to drill, and be careful not to apply too much pressure. Stop immediately after the paint film is drilled through, remove the drilling device, and remove the drill chips. 5.4 Turn on the light source of the microscope (2.2) and place the cone hole in the field of view of the microscope. 5.5 Focus the microscope on the busbar of the cone hole perpendicular to the main optical axis, and use the microscope's micrometer to measure the length of the paint film portion of this busbar (see the figure below). Substitute it into the following formula to calculate the paint film thickness: 6
Where: 8—paint film thickness,
—length of the paint film portion of the cone hole busbar.
National Bureau of Standards Issued on February 1, 1985
Implemented on April 10, 1985
Test result evaluation and test report
Test result evaluation
The test result is the arithmetic average of the three points. 6.2 Test report
The test report shall include the following contents:
Test period,
GB 4893.5--85
The name of the coating material and the brief coating process of the specimen, the storage time after the specimen coating is completed,
Test results, etc.
GB 4893.5--85
Appendix A
Drilling device
(Supplement)
This device is used to drill a tapered hole on the specimen when measuring the thickness of the paint film. A.1 Drill bit
The drill bit is made of ordinary high-speed steel (such as W18Cr4V, etc.), with a vertex angle of 120°, a diameter of 6mm, a length of about 48mm, a quenching hardness of not less than HRC63, and a taper and rod surface finish of not less than V9. The drill bit dimensions are shown in Figure A1.
It is recommended to use the 120° paint film thickness measuring drill produced by Shanghai Donghai Cutting Tool Factory. 18
Figure A1 Schematic diagram of drill bit size
A.2 Template
The template is made of ZL103 cast aluminum, with a 6mm diameter hole with a ZQSn10-5 tin bronze bushing at the front end, and the hole wall finish is not less than √8.
The template size is shown in Figure A2. wwW.bzxz.Net
After assembly, glue
o cloth sandpaper length 125
Schematic diagram of template size
A.3 Finger wheel
GB4893.5—85
The finger wheel is made of ZL103 cast aluminum and weighs about 350±15g. The finger wheel size is shown in Figure A3.
Ball R13
Screw M6×8
GB78-76
$6× 201.
Ball R10
Diagram of thumb wheel dimensions
1.5×45°
This microscope is used to measure the length of the cone hole generatrix. GB 4893.5--85
Appendix B
Measuring microscope
(Supplement)
B.1 The magnification of the microscope is 40×, the field diameter is not less than 4.0mm, the minimum reading value is not more than 2.5um, the working distance is not less than 40.0mm, the main optical axis and the bottom plane of the bracket are accurately at an angle of 60°, and a beam of uniform parallel light can be emitted to the object end in the direction of the main optical axis or close to the main optical axis.
B.2 The principle of the microscope optical path is shown in the figure below.
It is recommended to use the 60° paint film measuring microscope produced by Shanghai Daqing Optical Instrument Factory. Viewpoint
Gratings
Main optical axis
Additional instructions:
Optical path principle of microscope
Generator of conical hole
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and is technically managed by Shanghai Furniture Research Institute. This standard is drafted by Shanghai Furniture Research Institute. The main drafter of this standard is An Daiping.
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