I. Basic structural elements of sanding belts.
Sanding belts are generally composed of four basic elements, i.e., substrate, binder, abrasive and structural form. As shown in the table.
Substrate – cloth base, paper base, composite base
Abrasive – natural abrasive – natural corundum, garnet
Abrasive belts Ordinary abrasives – white corundum, brown corundum, zirconium corundum, silicon carbide
Super hard abrasives – artificial diamond, cubic boron nitride
Binder – animal glue, semi-resin, full resin, water-resistant products
Structure form – jointless abrasive belts
Jointed abrasive belts – docking, lap joint, etc.
II. Use range of sanding belts.
- panel processing industry: raw wood panels, rifled plywood, fiberboard, particleboard, veneer panels, furniture, building materials and others.
- Metal processing industry: non-ferrous metals, ferrous metals, etc.
- Ceramic, leather, fiber, paint, plastic and rubber products, stone and other industries.
III. Selection of sanding belts.
The correct and reasonable choice of abrasive belt is not only to obtain good grinding efficiency, but also to consider the service life of abrasive belt. The main basis for choosing the abrasive belt is the grinding processing conditions, such as the characteristics of the grinding workpiece, the state of the grinding machine, the performance and technical requirements of the workpiece, production efficiency, etc.; on the other hand, the characteristics of the abrasive belt must be selected.
- Selection of particle size.
Generally speaking, the choice of abrasive grit size is based on the grinding efficiency and surface finish of the workpiece. For different workpiece materials, the grit size range of abrasive belts for rough, medium and fine grinding is shown in the following table.
Workpiece material Rough grinding Medium grinding Fine grinding Grinding method
Steel 24-60 80-120 150-W 40 Dry grinding and wet grinding
Non-ferrous metals 24-60 80-150 180-W 50 Dry and wet grinding
Wood 36-80 100-150 180-240 Dry grinding
Glass 60-80-100-120 100-150 180- W 40 Wet grinding
Paint 80-150 180-240 280- W 20 Wet and dry grinding
Leather 46-60 80-150 180- W 28 Dry grinding
Rubber 16-46 60-120 150- W 40 dry grinding
Plastic 36-80 100-150 180-W 40 Wet grinding
Ceramics 36-80 100-150 180-W 40 Wet grinding
Stone 36-80 100-150 180- W 40 wet grinding
- choice of binder: abrasive belts can be divided into animal glue abrasive belts (commonly known as dry abrasive belts), semi-resin abrasive belts, and all-resin abrasive belts.
- All resin sanding belt and water-resistant sanding belt four. Its scope of application is as follows.
1) Animal glue abrasive belts are inexpensive, convenient to make and mainly suitable for low-speed grinding.
2) Semi-resin abrasive belts improve the poor moisture resistance and heatresistance of animal glue abrasive belts, and greatly improve the bonding.
It greatly improves the bonding performance and increases the grinding performance exponentially with little price increase. It is widely used in metal and non-metal grinding, and is especially popular in wood and leather processing industries.
3) All-resin abrasive belts are made of high-quality synthetic resin\\\and high-strength cotton cloth and superior abrasives, which are more costly, but they are wear-resistant and can perform powerful grinding. It is suitable for high speed, large cutting and high precision grinding. The above three types of abrasive belts are suitable for dry grinding and can also be ground in oil, but they are not water resistant.
4) Compared with the above-mentioned abrasive belts, water-resistant abrasive belts require more raw materials and have more complicated manufacturing processes, resulting in less production and higher prices. It has the characteristics of resin abrasive belts in addition to being used directly for watercoolant
- Choice of substrate.
Single-layer light paper 65-100g/M2 Thin, soft, low tensile strength and low cost. It is mostly used for fine or medium grinding, suitable for manual or vibrating sander to polish complex surface workpieces, curved wood sanding, metal and wood finish polishing, precision instrumentation repair and grinding, etc.
Multi-layer medium-sized paper 110-130g/M2 thicker, good flexibility, higher tensile strength than light paper. For manual or hand-held polishing machine, manufacturing page-shaped and roll-shaped sandpaper. Rust removal and polishing of metal workpiece, sanding of wood furniture, primer putty polishing, machine polishing of lacquer, case and instrument repairing, etc.
Multi-layer heavy-duty paper 160-230g/M2 is thick, flexible, with high tensile strength, low elongation and high toughness. It is used for manufacturing paper sanding belts and machine processing. Suitable for drum sander, wide belt sander and general belt grinder, mainly for processing plywood, particle board, fiberboard, leather and woodwork.
Lightweight cloth (twill) is very soft, light and thin with moderate tensile strength. For manual use or low load machine use. Metal parts sanding and rust removal, grinding and polishing, drum sander plate processing, sewing machine frame processing, light load sanding belt.
Medium type cloth (coarse twill) good flexibility, thick, high tensile strength. Machine Use General machine abrasive belts, and heavy duty abrasive belts, such as furniture, tools, electric irons, sanding steel sheets, engine blade type grinding processing, etc.
Heavy-duty cloth (satin) Thick, with higher weft strength than warp strength For machine use, suitable for heavy-duty grinding. Used for processing large area plates.
Compound base Extra thick, high strength, wrinkle, tensile and breakage resistant. For machine use. Heavy-duty abrasive belt, especially suitable for guillotine, fiberboard, plywood processing and inlay floor grinding.
Steel paper: particularly thick, high strength, low elongation, good heat resistance. Machine use. Mainly used for sanding discs, playing weld, rust removal, removing metal skin and oxide layer, etc.
- Selection of abrasives.
— usually the workpiece material with high tensile strength, choose corundum abrasives with greater toughness, higher pressure bearing, high resistance to crushing, high temperature resistance and chemical stability are better.
— For metal and non-metal workpieces with low tensile strength and high toughness, choose silicon carbide abrasives with high hardness, high brittleness and easy to break, such as: glass, brass, leather, rubber, ceramics, jade, chipboard, fiberboard, etc.
- Handling of sanding belts before use.
When using the sanding belt, make sure that its running direction is the same as the direction marked on the back of the belt to avoid the belt breaking during operation or affecting the surface quality of the workpiece in the processing plant. The belt should be rotated for a few minutes before grinding, and then start grinding when the belt is running normally. Before using the abrasive belt, hang the unpacked abrasive belt on a 100-250mm diameter tube for 2-3 days. The size of the tube diameter should be determined by the thickness of the abrasive belt. When hanging, the joint should be at the upper end of the tube, and the tube should be horizontal.