Troubleshoot
Pencil Hardness
Pencil Hardness
I. How to use the pencil hardness tester:
1. It must be carried out in a good laboratory environment, and start the test with a harder pencil
2. Place the installed pencil hardness tester gently on the surface of the object to be tested
3. Grasp both sides of the pulley with your fingers, and push forward 10mm at a speed of 5…10cm/sec, one time, no dragging back and forth
4. Observe whether the surface of the sample is scratched with the naked eye?
5. In the order of pencil hardness, gradually test from hard to soft until the tip of the pen does not scratch the coated surface at all
6. Note: Any scratches or damage caused by the pen tip are regarded as scratches.
II. Pencil cutting specifications:
1. Use a sharp blade to cut off the xylem about 5mm to expose the pencil core, but not damage it
2. Take No.400 sandpaper and grind the pencil vertically on the sandpaper at an angle of 90 degrees
3. When the nib is ground into a flat surface, it can be used as a spare
4. After each measurement is completed, please repeat steps 1…3 to reprocess the special pencil for testing the tip Wolff-wilborn pencil hardness, 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 1H, 2H, 3H ,4H,5H,6H,7H,8H,9H
III. Judgment method of Wolff-wilborn pencil hardness:
1. You must record each pencil. Will it cause scratches on the surface of the sample?
2. Judging from the order of hard to soft, the first pencil that does not leave scratches (the length of the line is at least 3mm) is the final “pencil hardness”
3. Reference information: There is another "Wolff-Wilborn" specification, which is a sequential test from soft to hard. The first pencil that will leave scratches is regarded as the final "Wolff-wilborn pencil hardness" ”
4. Therefore, in your experiment report, please indicate which hardness specification is used to avoid misuse. Note: Pencil hardness grade (softest) 6B 5B 4B 3B 2B B HB FH 2H 3H 4H 5H 6H 7H 8H 9H (the hardest) The softest medium the hardest
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