One of the casting molds is called lost foam mold casting. One of the common disadvantages is the deformation of the casting blank. During machining, the blank is often scrapped because the size and shape tolerances of the blank do not meet the requirements of the drawings. What is the deformation of the blank?
- Model deformation caused by the molding process: when the white film is taken out after molding, because of the irregular shape of some parts, it is more complicated, and physical drawing deformation occurs due to the effect of air pressure and water pressure and manual mold removal during mold removal.
Solution:
- When processing the mold, try to use Teflon-coated surface. 2. The angle of the mold draft is appropriate; 3. Use the appropriate air pressure; 4. For the white mold of the shell, it can be fixed with tape; 5. Make corrections when bonding and combining deal with.
- The white mold is deformed when the white mold is dried: the placement of the white mold is unreasonable during drying; the code layer is too high, which will cause deformation; the drying time of the white mold is not suitable, causing the linear scale of the white mold to be shortened insufficiently or shortened Too much, the size of the blank does not meet the requirements of the drawing after pouring.
Solution:
- The drying rack is used when the white mold is placed for drying, that is, the space of the drying room is not wasted. It does not deform the white mold.
- Dry the moisture inside the white mold, so that the residual foaming agent inside the white mold can escape. The white mold will shorten the linear scale during the drying process, and the mold factory will leave a margin for the shortening of the white mold in the design. But for different products, the same drying temperature and drying time, the linear shortening of the white mold is not the same, so different products have different drying processes.