How does the Purson Combined Pencil Hardness Tester test the hardness of the coating?

Pushen Combined Pencil Hardness Tester is a trolley-type pencil Hardness Tester, which is used to test the hardness of paint film coating. The appearance structure of the pencil Hardness Tester is as follows:

The specific operation method and precautions are introduced as follows:

Steps

1. Test piece production

Take a test piece with a size of 150*70*1mm, apply the sample on it, and place it in a drying box for 24 hours (until it dries).

2. Test start

First place the test piece on the test piece platform, put CT-291 on it, then choose a suitable pencil, cut off the wooden part, so that the core is about 3mm long, take out the sandpaper and grind the pencil core on it, so that the front end is flat If the corners are sharp, insert the pencil into the 45-degree hole and lock it (put the level on the machine to make sure it is level). Move the right hand wheel in parallel for about 3-5mm (about 0.5cm per second) to remove the test piece and wipe it. clean. If there is no visual trace, then choose a hard pencil (if there is a scratch, choose a soft pencil), try it again, and so on.

3. Judgment method

The test of the above method can be judged according to two principles: a. no bracket b.

Precautions

1. Every time the pencil is tested, turn the direction once, then take it out, and grind it with sandpaper before trying again. Remember that the center of the pencil cannot be rounded, and the sharp edges cannot be damaged.

2. The hardness value is the former of the pen that just failed the test. If H has no scratches and 2H has scratches, the hardness of the test piece is H.