[Surface treatment] Brief description of surface "roughening"

As the name suggests, "roughening" refers to the roughening of a smooth surface through physical or chemical treatment. The most common physical treatment is the use of aluminum oxide emery grit, which is determined by the particle size and size of the emery grit. The pressure of the sandblasting equipment produces surface effects of different roughness. Chemical treatment uses chemical liquid to erode the surface to produce a rough feeling. For aluminum materials, the commonly used chemical liquid is to use products such as sodium hydroxide or ammonium fluoride for treatment.

Physical roughening and chemical roughening 

Physical coarsening

We often see and hear about physical roughening, including corundum sand, glass sand, stainless steel sand, vibrating stone and other related materials. Their use needs to be based on the material type, surface roughness and chamfering cutting needs, and select the appropriate material. Abrasive materials are used for grinding, and various types of abrasive materials will not be discussed here.

Video sharing : https://youtu.be/-NvYZ0H_7tI?si=b2ogJeSe8Wd4MHsP

Chemical roughening

In the video, we put the aluminum material into the acidic acid detergent, which erodes the surface of the material and produces a roughening effect on the surface of the workpiece. I would like to remind everyone who reads the article that because the acidic pear agent is an ammonium fluoride system and will corrode glass materials, you must use a plastic container if you want to conduct tests!!!

After being impregnated with acidic pear ground agent (as shown in the picture above), the original surface becomes roughened (white) due to bite erosion, and the roughness is more uniform and can be close to the degree of physical roughening; the roughness is It is adjusted through the time of biting and etching. The thicker it is, the longer the time of biting and etching is required. Furthermore, heating the liquid can achieve better results.

Roughness representation

Ra- centerline average roughness

Ry or Rmax - maximum roughness

Rz - ten-point average roughness

The most commonly discussed one is the Ra value. There is no further explanation on the calculation methods of these three values. The relevant values ​​can be measured using a roughness meter.