What are the main differences between coarse sand and fine sand? What machinery is needed for sanding?

Coarse sand and fine sand refer to different gradations of sand particles based on their size and grain diameter. The main differences between coarse sand and fine sand are:

1. Grain size: Coarse sand has larger particles with a grain diameter typically ranging from 2mm to 8mm. Fine sand, on the other hand, has smaller particles with a grain diameter ranging from 0.15mm to 2mm.

2. Application: Coarse sand is commonly used in construction applications such as concrete, mortar, and plaster, as well as for landscaping and drainage purposes. Fine sand is used in a variety of applications, including paint, plaster, and mortar, as well as for water filtration and other industrial purposes.

3. Grading: Coarse sand usually uses screening equipment with larger mesh sizes (such as 20-30 millimeters), while fine sand is graded using screening equipment with smaller mesh sizes (such as 1-2mm).

Sanding machines are mainly used for surface sanding, polishing, and polishing of materials such as wood, metal, and plastic. There are several common sanding machines:

1. Fixed sanding machine: This type of sanding machine usually has a fixed workbench to support the workpiece to be processed. The sandpaper or grinding wheel is driven by a motor to rotate or vibrate to achieve a sanding effect on the surface of the workpiece.

2. Portable sanding machine: This type of sanding machine is usually small and easy to carry and operate. They are usually powered by batteries or plugs and are suitable for on-site or small workplaces.

3. Vertical sanding machine: This type of sanding machine usually has a vertical workbench used to support long or cylindrical workpieces. The sandpaper or grinding wheel is driven up and down by a motor to achieve a sanding effect on the surface of the workpiece.

The factors that need to be considered when selecting and using a sanding machine include: the type and hardness of the material to be processed, sanding effect requirements, production efficiency, workplace, and safety factors.