Die Casting vs Sand Casting

Sand Casting compared to Die Casting

Sand molding has a quick set-up time. Patterns can be made cheaply of almost any material, since the pattern itself has no contact with the cast metal. The sand used for the mold is cheap and reusable. This makes sand casting cost-effective for prototyping and short runs.

The dies used for die casting are usually made of hardened tool steel, because they must withstand high pressure and temperature. Because of this they are very expensive, and there is a high start-up time and expense. Lower labor costs on a long run may offset the initial setup costs, however.

Sand casting is an ideal method for aluminum casting. Aluminum is heated to very high temperatures, which decreases the life of the dies used for die-casting. A well-maintained die used for aluminum casting may have a life of 100,000 cycles, while a sand casting pattern can be used for an unlimited number of casts.

Die casting may produce thinner walled pieces. There are limits, however, in the size of parts that can be produced using die casting. The upper limit is around 70 lbs for an aluminum part.

Parts of almost any size can be produced using sandcasting. One casting can create the entire bed for one rail car!

There are trade-offs to explore among the casting processes. The chart below is a general guide.

 Sand CastingDie Casting
Startup TimeA few daysSeveral weeks
Initial ExpenseInexpensiveExpensive
Labor CostsHigher labor costs on long runsLower labor costs on long runs
FinishPebblySmooth
AlloysHigh temperaturesHigh fluidity materials; Better life with lower temperatures (e.g., zinc)
Product SizeUnlimitedCasting weight must be between 30 grams (1 oz) and 10 kg (20 lb).
Casting must be smaller than 600 mm (24 in.).
Wall ThicknessThicker than die castingThinner than sand casting