Quality inspection of tunnel furnace assembly line workbench:

Quality inspection of tunnel furnace assembly line workbench:

1. The working surface should not have rust, scratches, scratches, or other appearance defects that affect its use.

2. The working surface should not have casting defects such as sand holes, pores, cracks, slag inclusions, and shrinkage porosity. The surface of various castings should be cleaned of molding sand, and the surface should be flat and painted firmly. Each edge should be rounded off. On flat working surfaces with an accuracy level below "00", it is allowed to block sand holes with a diameter less than 15mm using the same material, and their hardness should be lower than that of the surrounding materials. There should be no more than four blocked areas on the working face, and the distance between them should not be less than 80mm.

3. On the opposite two sides, threaded or cylindrical holes should be provided for installing lifting facilities such as handles and lifting rings. When designing the lifting position, consideration should be given to minimizing changes caused by lifting.

4. According to user requirements, after setting threaded holes or grooves on the working surface of the board, these areas should not have protrusions higher than the working surface.

5. It should be made of fine grained gray cast iron or alloy cast iron.

6. The hardness of the working surface should be HB 170-220.

7. The working face should adopt scraping technology, and for "3" level flat working faces, planing technology can also be used. The surface roughness of the planing working surface should have an arithmetic mean deviation Ra value of no more than 5um according to the contour

8. It should undergo stability treatment and demagnetization. Flatness: can be divided into three levels: laboratory level (Reference), calibration level (Master), and tool room level (Working)

① AA level: its flatness( μ m) =1+1.6D2 (D is the diagonal length or diameter of the platform), used for height measurement and commonly used in laboratories.

② Grade A: Its flatness is twice the error of Grade AA and is commonly used for tool inspection in tool inspection rooms.

③ B-level: Its flatness is four times the error of AA level, commonly used in tool inspection rooms or on-site inspection of measuring tools or marking.

Surface grinding: In early times, people used three platforms to match each other to produce a true flat surface. A skilled and patient grindstone can produce incredible levels of flatness by simply using three platforms to match each other and perform multiple 90 degree rotations without relying on any measuring instruments.

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