Zinc Die Casting

INNO Die Casting > Zinc Die Casting

What is Zinc Die Casting?

 

die-casting-machine-hot

Zinc die casting is one of the most common die casting manufacturing process to produce high volume metal parts with excellent physical and mechanical properties .(There are totally zinc, aluminum, and magnesium die casting).

 

Compared to aluminum and magnesium, zinc has low melting point, good corrosion resistance, and excellent flowability, it be used for some thin wall, high resistant mechanical properties, and complex in shape of casting components. like automotive housing, industrial meters/, and other heavy equipment.

 

The process of  zinc die casting alloys utilize an hydraulic press (the gooseneck pump)  that allows metal to be injected into a cavity at extremely high pressures.Normally a zinc die casting is produced with hot chamber casting machine with much higher production efficiency.(shorter cycle time) than aluminum and magnesium die casting. If you need high production volume, then zinc die casting would be your first choice.

The Advantage of Zinc Die Casting

 

  • zinc die casting partsExcellent corrosion resistance(PH 4~12)
  • Good stiffness and excellent impact strength
  • High electrical and thermal conductivity
  • Complex geometries and high quality finish
  • Available for thin wall parts
  • Tight tolerance available(+/-0.005 min.)
  • High production efficiency(short cycle time)
  • Lower cost for raw material
  • Recyclable and reusable in production
  • Zero Draft Angle Castability
  • Less material needed when casting process
  • Fast production time compared to aluminum

The Flow Chat of Zinc Die Casting Process

 

 

The Flow Chat of Zinc Die Casting Process

The Six Typical Zinc Die Cast Processes

 

Zinc Die Casting MachineNowadays there are mainly two different zinc die casting processes in die casting industry, they are hot chamber and cold chamber.

 

The hot chamber process requires to use alloys with low melting temperatures and a low attack rate on die casting mold tool steel.  This process is the most common way of manufacturing zinc die casting products.  In this process, the metal pump (gooseneck) is immersed in the molten zinc alloy,  and the pumping metal directly ejected to the mold cavity from the furnace of casting machine quickly, then it solidified to become the desired casting product..  So the hot chamber die casting system would have shorter cycle times, smaller runner systems, and lower  costs compared to cold chamber process.

 

The cold chamber process is very similar to the hot chamber process except that the molten metal is poured into a horizontal cylinder when cold chamber process.  because the raw material of cold chamber process has higher melting point that should be pre-melt and poured into a die casting machine.

Whatever which type of die casting process is , both of them consist of six main stages, which can be described as below.

 

 Step 1: Material and Mold Tool Preparation

Prior to casting process, we need to get right material to be melted with a certain temperature on the furnace of die casting machine. Meanwhile, our die casting mold tool should be correctly equipped on casting machine, and get the mold tools cleaned and tested if it can open and clamp smoothly.

 Step 2: Clamping

After raw material and mold tool were properly located, it’s the time to clamp the mold tool tightly on the die casting machine as needed. Sufficient force must be applied to the mold tool and keep it securely closed while the molted material is injected.

 Step 3:  Injection

In this stage, the molten metal is injected into the mold to fill in the full cavity of mold tool by a high pressure, normally a heavy zinc die casting parts requires longer injection time. And the lighter parts need shorter injection time. A sufficient injection is very important as different part structure and thickness of wall. If shorter injection for a big parts, there will not be enough material to fill in. On opposite, a longer injection time would result in overflowing problem. The best way to balance it is to operate the injection trail by experienced technician.

 Step 4:  Cooling 

The molten metal that is injected into the mold tool will begin to cool and solidify immediately after it stay in the mold cavity. Normally the cooling time is about 3~10 seconds. However this time might vary a little bit for different size, shape, and heavy of a casting product. For example, the thicker wall of part and big size part would require longer cooling time.

 Step 5:  Mold Open and Ejection 

– After material solidification and cooling stage has completed sufficiently, the mold tool opened, and the ejection pin pushes the molded product out of the mold. A proper ejection pins with reasonable location and size would affect if the casting parts can be ejected smoothly. Normally a bigger casting parts requires bigger ejection pins, otherwise the pins might break or not enough to eject parts from mold tool.

 Step 6:  Trimming 

When the casting part is ejected from a mold tool, it comes with injection gate and runner system. So we need to remove those extra material from our desired parts, which can be operated either by manual or automation.

The Surface Treatment of Zinc Die Casting

 

With rich experience and resource at die casting industry, we provide customers one stop die casting service with full surface treatment including (but not limited to):

  • Deburring & Polish
  • Electro-coating(Chrome, Nickel, Copper, Golden…)
  • Sand Blasting
  • Powder Coating
  • Electrophoresis
  • Anodizing
  • Painting
  • Silk Screening

 What is Zinc Alloy? 

 

Zinc alloys are zinc-based alloys that involved in other elements like aluminum, copper, magnesium, cadmium, lead, and titanium. Zinc alloy has low melting point, good fluidity, easy fusion welding, brazing and plastic processing. It also has good resistant to corrosion in the atmosphere. The blind material is easy to be reused and remelted. However, the brittleness is low and it is easy to cause natural aging to cause dimensional changes.

 

 

The Difference of Zinc Alloy and Aluminum Alloy 

 

  1. The melting temperature of zinc alloy is about than 400 degrees, however the melting temperature of aluminum alloy is more than 700 degrees.

2, Because of different melting temperature, zinc casting process uses a hot chamber casting machine while aluminum casing using a cold chamber casting machine.  

  1. The overall hardness and tensile strength of zinc alloy is higher than aluminum(zinc 65-140, tensile strength 260-440, the hardness of aluminum alloy is 45-90, tensile strength 120-290)
  2. The manufacturing cost of zinc die casting is more expensive than aluminum die casting.

 Common Zinc Die Casting Alloy Material

Zamak 3

Zamak 3 is the most wide use of zinc alloy material when we consider to use a zinc die casting alloy, as it provides excellent mechanical and physical properties. For example, it gives stable dimension, good durability and impact strength. This is why 60% of zinc die casting parts are made of Zamak 3.

Zamak 5

ZAMAK is an improvement material based on Zamak 3, which offers a slight harder. However this is also reduce its ductility that might affect the secondary process.  If there is an extra measure of tensile performance needed, No. 5 alloy is a good choice.

 The Mechanical  Properties of Zinc Alloy 

 

The Mechanical Properties of Zinc Alloy

 The Physical  Properties of Zinc Alloy 

 

The Physical Properties of Zinc Alloy

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