Die Casting vs. Other Processes
Die casting vs. plastic molding - Die casting produces stronger parts with closer tolerances that have greater stability and durability. Die cast parts have greater resistance to temperature extremes and superior electrical properties.
Die casting vs. sand casting or permanent mold - Die casting produces parts with thinner walls, closer dimensional limits and smoother surfaces or even a pattern finish. Production is faster and labor costs per casting are lower. Finishing costs are also less.
Die casting vs. forging - Die casting produces more complex shapes with closer tolerances, thinner walls and lower finishing costs. Cast coring holes are not available with forging.
Die casting vs. stamping - Die casting produces complex shapes with variations possible in section thickness. One casting may replace several stampings, resulting in reduced assembly time.
Zinc Die Cast Advantages
Today‘s zinc casting alloys are strong, durable and cost effective engineering materials. Their mechanical properties compete with and often exceed those of cast aluminum, magnesium, bronze, plastics and most cast irons. These characteristics, together with their superior finishing capabilities, make zinc alloys a preferred material choice for today‘s industries, because they‘ll save you time and money.
Less Material is Required
Zinc‘s superior casting fluidity, strength and stiffness permits the design of thin wall sections for reduced weight and material cost savings.
Machining Operations are Reduced or Eliminated
Due to the superior net-shape casting capability of zinc die cast alloys, machining can be eliminated or drastically reduced.
Assembly Operations are Reduced
Entire assemblies can be cast as a single unit, eliminating the need for expensive manual assembly operations.
Faster Production and Extended Tool Life
Die-cast manufacturing rates for zinc are typically much faster than for aluminum, or magnesium. Factor in that tool life will often exceed 1 million casting cycles, tooling and machine usage charges are dramatically reduced.
Overall Efficiency and Environmentally Green
Zinc takes less energy to melt with a melting point that is only 787℉ compared to aluminum‘s melting point at 1,221℉. This also gives zinc an advantage over aluminum on the recycling end because it takes less time and energy to melt zinc down than aluminum.
Smoother Surface, Better Finish
Zinc castings come out with a much smoother surface than aluminum castings, which makes them easier for a variety of different finishes. Aluminum castings usually have to be buffed before they can be finished which represents a significant increase in processing costs.
Advantages of Zinc over Aluminum Die Casting
If you’re considering aluminum die casting, there are several reasons why Zinc die casting could be a better option for you.
10 x‘s greater tool life
A Zinc die‘s tooling life can be more than 10 times longer than that of an aluminum die! Lower casting temperatures for zinc are easier on tools because they create minimal thermal shock and prolong die casting tool life. With dies costing as much as $40,000 each, having a long lasting tool can represent a significant cost savings.
Superior thermal conductivity
Zinc is a better conductor of heat than Aluminum which makes it perfect for applications like heat sinks or electrical components. This means Zinc is able to absorb and dissipate the heat better than Aluminum.
Low melting point = cost savings
Zinc melts at 787.2℉ whereas Aluminum melts at 1,221℉. This gives Zinc an advantage because casting can use a process called "Hot Chamber" casting which is quicker as well as being less costly than "Cold Chamber" methods.
Faster cycle times = better pricing
Using the Hot Chamber process also gives Zinc a major advantage over Aluminum because the hot chamber process goes so much quicker than Cold Chamber. In cold chamber, Aluminum needs to be manually poured into the die either by hand or using a robot. Using hot chamber casting, the molten liquid zinc is shot into the die using a highly pressurized "plunger" which systematically shoots the zinc through the die.
Thinner wall stock
ZAMAK alloys have exceptional casting fluidity. It‘s possible to cast walls in ZAMAK as thin as .25 inches. Thinner, stronger walls results in smaller and lighter products with lower costs.
Less machining required for tight tolerances
Zinc die casting has tighter tolerances than Aluminum or plastic die casting, which often eliminates the need for additional machining. When no additional machining is needed, it‘s called "Zero Machining" manufacturing. This is one of the major advantages of Zinc die casting.
Superior for decorative finishing
ZAMAK alloys have a better surface for finishing because Zinc comes out of casting with a smoother skin. Because Aluminum has to be so much hotter than Zinc, the thermal shock from being put in a die produces a part with a surface that can be more pitted. Chrome finish amplifies every defect in a part, which makes Zinc much easier to finish compared to Aluminum. Zinc die casts can be easily polished, plated, painted, chromated or anodized.
Zinc alloys are some of the strongest and toughest materials for die casting. Neither plastic, gray cast iron, nor Aluminum withstand impacts as well as Zinc alloys do.
A variety of high quality surface finishes is another major advantage that zinc has over other materials.
A list of the zinc alloys that Connecticut Precision Castings currently utilizes.