Some solutions for placement and deformation of precision castings

The wall thickness of precision castings varies with the appearance of precision castings, often referred to as staggered boxes, staggered edges, and eccentric cores. There are many reasons for this problem, such as poor mold matching, worn positioning pin sleeves, and movement of the mold on the precision casting Etc. Error in the model, form or another part of the clay box. The sand box may also be inappropriate; the clay core may be deformed during manufacturing, baking and transportation; the sand box may be moved before pouring because the mold to be poured is neglected.

In order to avoid the problem of wall thickness of precision castings, on the one hand, the damage to the castings and sandbox should be repaired immediately to deflect the precision castings; and whether the positioning pins and positioning pins are moved and damaged, check the positioning pins and pin holes on the sandbox and template. Wear and deformation.

In addition, the gap between the cores needs to be strictly enforced. When precision casting templates, positioning pins should be used to ensure that the upper and lower box precision castings have the same appearance; when necessary, tenons can be used to avoid skewing. Clay cores do not need to be supported by clay cores .

The deformation of precision castings is caused by casting stress. The appearance and size of precision castings are inconsistent with the type. The reason is simple. Due to the large thickness difference between the upper and lower parts, the cooling temperature difference is large. The ridge is fast and the shrinkage is fast. Since the beam is connected up and down, the beam is The thickness not only shrinks due to the decrease in temperature, but also expands due to thin compression. On the contrary, thin shrinking reduces the shrinkage, resulting in a thicker thickness than the thick one. The bending of the cast aluminum dotted line indicates that the beam has great thermal stress.

The typical bending deformation of precision castings is the machine tool bed. Due to the thick surface of the bed guide rail and the thinness of the remaining parts, uneven cooling speed and bending deformation, a reverse deformation casting process is established to overcome it.