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How to grind thermal spray coating?

Author:moao Time:2022-02-28 09:43:55

When grinding the coating, we should pay attention to the fact that there is a great difference between the forging and casting parts of the same material. Excessive grinding pressure will cause the transfer or movement of particles on the surface of the coating, and even cause cracks in the coating. Due to poor thermal conductivity of the coating, there should be sufficient cooling medium during grinding.

thermal spray coating

In the grinding process, due to the high hardness of thermal spraying coating, diamond abrasive tools are used for machining, mainly diamond grinding wheel and diamond sanding belt.

The selection of grinding wheel should take into account such factors as coating type, coating hardness and structure, workpiece size, grinding quantity and surface roughness requirements, type, state and capacity of grinding machine, etc. Diamond grinding wheel has durability and can grind all kinds of hard alloy, metal, ceramic and cermet cleanly.

Generally speaking, the finer the spraying powder, the lower the porosity of the coating, the more uniform the coating, the better the finish after grinding.

Factors such as coating type, hardness, workpiece size and shape, grinding quantity, surface finish requirement and grinder type should be considered when selecting grinding wheel. Generally speaking, for wear resistant coating coarse grinding particle size in 125-150 mesh, for fine grinding particle size in 380-400 mesh.

thermal spray xcoating grinding

In order to achieve the desired grinding effect, when light grinding pressure or high grinding speed is required, a softer grinding wheel should be used to make the contact area large. When using heavy grinding pressure or require lower roughness, should use a hard level of grinding wheel binder binder type are vitrified bond and thermosetting resin binder Vitrified bond commonly used for metal coating. Can improve the grinding speed and achieve accurate fit tolerance, and not affected by acid oil and water temperature changes. For ceramic coating generally choose resin binder, used for fast grinding and produce low surface roughness grinding wheel abrasive particle size selection to process a lower roughness should be used for grinding wheel with finer sand particles coarse grinding can be used 30-60 mesh particle size, fine grinding 60-120 mesh particle size factors affecting the cutting performance of grinding wheel characteristics are mainly by abrasive. Grain size bond hardness structure grinding wheel width and other factors determine.

1. Abrasive

Abrasive is the main component of grinding wheel. It has high hardness, wear resistance, heat resistance and certain toughness to withstand the cutting heat and cutting force during grinding. Abrasive is the cutting material, it and turning tool materials should have high hardness, high wear resistance, enough bending strength and impact toughness, high heat resistance, etc. At present, green silicon carbide, artificial diamond and cubic boron carbide abrasives are used for grinding high hardness thermal spraying coatings. A lot of experiments show that the performance of artificial diamond wheel is far better than that of green silicon carbide and white corundum wheel.

2. Grit

Grit refers to the size of abrasive particle size.

Particle size is divided into abrasive and micro powder two kinds. The abrasive with particle size greater than 40 μ m is called abrasive grain. Abrasive with particle size less than 40 μm is called micropowder.

The force of grinding wheel has great influence on the roughness and grinding efficiency of grinding surface. Coarse abrasive, grinding depth, high productivity, but the surface roughness value is large. Otherwise, the grinding depth is uniform and the surface roughness is small. So coarse grinding, generally choose coarse particle size, fine grinding choose fine particle size. When grinding soft metal, coarse abrasive grains are used, and when grinding brittle and hard materials, fine abrasive grains are used.

The selection range of particle size of artificial diamond grinding wheel is:

Surface roughness










vitrified diamond grinding wheel for thermal spray coating   diamond grinding wheel for thermal spray coating

The selection range of particle size of CBN grinding wheel is:

Surface roughness










3. Bond

‍ Bond is the material that binds the abrasive grains together to form an abrasive tool.

The strength, impact resistance, heat resistance and extreme corrosion resistance of grinding wheel mainly depend on the type and nature of bond.

4. Hardness

The hardness of grinding wheel refers to the degree of difficulty for the abrasive particles to fall off under the action of external force when the grinding wheel is working. The grinding wheel is hard, indicating that the abrasive particles are difficult to fall off.If the grinding wheel is soft, it is easy to fall off.

The hardness levels of artificial diamond grinding wheel are ZR, Z, ZY, Y, and only the resin bonded artificial diamond grinding wheel has hardness levels. ZR and Z class are generally selected.

5. Grinding wheel width

The width of grinding wheel has a great influence on the radial component of grinding, and the radial component is easy to cause vibration, which is detrimental to the machining quality and grinding wheel durability. Therefore, when grinding refractory thermal spraying coating, narrow grinding wheel should be selected as far as possible (under the condition of allowable grinding wheel strength), and its width should be about 10% of the diameter of grinding wheel.

6. Organization

The structure of grinding wheel reflects the size of chip space, which can be divided into three types: tight, medium and loose, and the number ranges from 0 to 12. The grinding wheel with medium structure is generally used. In order to avoid grinding wheel being "jammed", especially in grinding inner circle, loose organization (10-12) grinding wheel or big porosity grinding wheel can be used when grinding hard thermal spraying coating.

The surface quality of the workpiece grinding with diamond sanding belt is high, which is mainly manifested in small surface roughness value, good residual stress state, and no microscopic cracks or metallography changes on the surface. From the perspective of surface roughness, belt grinding has reached RA0.01mm, achieving the effect of mirror grinding, and for the roughness value above Ra0.1mm, it is very easy to achieve.

Moresuperhard can provide complete grinding solution for thermal spray coating grinding, we have vitrified and resin diamond grinding wheel for thermal spray coating. After grinding, the surface rouhness is perfect.



---EDITOR: Doris Hu

---POST: Doris Hu



TAG:   vitrified diamond grinding wheel resin diamond grinding wheel +86-371-8654-5906 +86 17324838957 Zhongyuan Rd, Zhongyuan District, Zhengzhou, China


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