When using a ceramic foam filter, the pore size of Ceramic Foam Filter Uses should be determined according to the quality requirements of the casting and the number of inclusions in the molten metal; the size of the filter should be determined according to the pouring speed and pouring weight. In order to ensure the filtering effect of the filter, the placement of the porous ceramic filter, and the design of the gating system should also follow certain specifications.
Ceramic Foam Filter Uses
The ceramic foam filter must be placed as close as possible to the casting to obtain the maximum filtration efficiency and flow adjustment. Considering practical factors, such as the position that can be placed in the mold and the design of the gating system, the filter is often placed in the runner. Sometimes the ceramic filter for foundry is placed at the bottom of the sprue, but this is not recommended. Because the filtering effect and adjustment of the flow of the ceramic foam filter will be affected by the turbulence from the bottom of the sprue to the runner. It is recommended to install the filter vertically in the runner.
The smaller the pore size, the better the filtering effect, but the greater the obstacle to flow. The metal foam filter pore size standard is 10ppi (10 holes per inch) (coarse), 15ppi (15 holes per inch) (medium) and 25ppi (25 holes per inch) (fine). The standard of the pore size of the cast steel filter is 6, 10ppi. Due to the large amount of scum after the treatment of ductile iron, most ductile iron factories use 10 or 15 ppi filters. Some high-quality ductile iron parts manufacturers use 25ppi filters, because small pore size filters can provide better filtering results. Under these circumstances, special attention must be paid to the stability of the process parameters to obtain a very clean ductile iron liquid. The size of the filter is often chosen to be quite large to reduce the filter blockage caused by the large amount of scum inclusions. For gray iron parts, 15ppi filters are the most widely used. For some important applications, such as compressor cylinders and other pressure-resistant parts, 25ppi filters are recommended. This kind of small pore size filter can more effectively filter out the small size inclusions that can cause leakage of the die casting.