The sand casting process offers many distinct advantages when compared to alternative metal casting methods. When the versatility, unit costs, quality, availability and all other factors are considered, using sand molds for manufacturing aluminum castings is the clear choice.
Aluminum parts cast in sand molds, and which will be machined, are highly competitive with gray iron, notwithstanding the higher cost per pound of material. The following represents some of the clear advantages of the aluminum sand casting process.
Flexibility of Design
Intricately cored parts and parts with feet, bosses or other unwidely protuberances can be cast soundly.
Wide Range of Alloys and Properties Available
Properties range from 16k to 50k tensile with varying degrees of machinability, corrosion resistance, etc.
Lowest Tooling Cost - Shortest Lead Time
Unmachined patterns are cheaper and faster to build lower overall the overall cost of casting production and shortening turn-around time.
Long Tool Life
The aluminum sand casting process uses expendable molds. Hot metal, which causes deterioration of permanent-mold tooling and adversely affects quality of the cast parts, never touches the tooling (pattern).
High Production Rates for Large Range of Parts
The many molding options available to sandcasters, from squeeze jolt machines to high pressure automatic molding machines, combined with the use of multi-impression matchplates, permits the manufacture of thousands of parts per day.
Ease of Product Modification
With shorter “Life of Product” cycles than in the past, the ease of altering tooling is increasingly important.
Least Sensitive Gating, Feeding and Heat Removal System in Mass Production
Pouring temperatures in permanent molds should be held to +/- 20° for optimum results. In sand, good castings can normally be obtained with temperature differences as high as +/- 40% and generally in a much lower temperature range.
High Density Molds Produce Good Surface Finish
Higher mold squeeze pressures combined with technological improvements in sand preparation produce castings with a surface finish that rivals the permanent mold processes.