Machine tool castings occasionally have defects in casting production due to improper operation and other reasons. There are several types of machine tool casting defects that are currently known to be common:
1. Cracking of machine tool castings Some machine tool designs are prone to large gaps between thick and thin places. Therefore, similar problems in casting cracking prevention and control will occur at their junctions or corners. The main solutions are:
① At the interface between thick and thin walls, appropriately put "reinforcing ribs" (if there is a significant effect on the size of the casting, you can take them out after roughing); for the "cracking" problem at the corner, use Fillet radius approach.
② In the treatment of materials, inoculants should be used for the corresponding inoculation treatment to improve the strength of the casting and its ability to resist cracking.
③ When designing the pouring system, the principle of simultaneous solidification should be adhered to to ensure that the pouring work can be completed in a short time.
④ Prolonging the insulation time in the box can also avoid the quality problem of cracking of the casting, but too long the insulation time will affect the normal production process.) The insulation time in the box should be reasonably adjusted according to the characteristics of the casting in different seasons, which is also effective. Measures to avoid cracking of castings.
⑤ For such castings that are easy to crack and have obvious stress, artificial aging treatment is one of the links. During the processing, the position should be stable to ensure that the force and heat received by each part are uniform.
的变形机床铸件本身的长宽比例较大，导致其中间出现明显的变形而使得尺寸不合并引起铸件报废，解决可以从以下几点入手： 2. Deformation of machine tool castings The length-to-width ratio of the machine tool castings is large, resulting in obvious deformation in the middle, which causes the dimensions to be merged and cause the casting to be scrapped. The solution can be started from the following points:
① Adjust the deflection based on the differences in the structure of different castings, usually between 2 and 4 ‰.
② The locking force of the box in all directions should be kept uniform. For large castings using the pit modeling process, the box pressing force should also be kept uniform.
③ When designing the pouring system, one channel should be opened at each end to achieve the purpose of simultaneous pouring.
④ The artificial aging heat treatment method can be used to treat some castings with less obvious deformation.
3. The functional characteristics of core drifting machine tools for machine tool casting require it to have a high degree of wear resistance, stability and good shock resistance, but it must not be too large, which makes many parts of the machine have to be connected by ribs. In this way, many cavities will be formed inside the machine tool, and the mud cores constituting these cavities are supported by mud cores to achieve the purpose of support and fixation. If it is not handled properly, the quality problems of casting drifting cores will occur. The technological countermeasures that should be adopted for this are:
①The wall thickness is obvious at the position supported by the mud core brace, especially in the upper part of the equipment. The mud core brace is mainly made of cast iron rod material. In the selection of the diameter, it should be kept sufficient under high temperature molten iron. The supporting force is to be able to blend well with the solution.) In addition, the ratio of the diameter to the thickness of the casting should be kept at about 1: 4, so that it has a larger fusion area with the solution.
② When designing the pouring system, care should be taken not to allow the inner runner to directly impact the core support.
③ Under the premise of other process procedures, the pouring temperature can be adjusted appropriately.
In addition, when furan chilled resin is used to make machine tool casting shapes, porosity is likely to be generated in the guide rail part, and mainly subcutaneous porosity. After rough machining, it can be clearly observed, and trachoma generally appears on the surface.
1. To grasp the nitrogen content in the resin, it is usually not suitable to be too high, and the amount of resin added should be controlled at 1%.
2. When using water-based paint, it should be dried in time. In winter, if the box is closed later, water vapor will condense, so it should be baked properly before closing.
3. When designing the pouring system, we should resolutely avoid the emergence of sundries and other debris. Usually, the guide rail of the machine tool should be placed under the mold.
Adopting appropriate technology to deal with various defects in machine tool casting can further improve the quality of machine tool castings and promote the improvement of enterprise technology management level.