How is the die casting manufacturer since 2014? Zinc alloy is increasingly used in different industries nowadays, from furniture to iron products, clothing to machinery, automobile, electronics, pneumatic and hydraulic components, because it can be simply used for fast and slow melting temperature cycle (400 to 500 ° C). Using zinc die casting instead of other materials has a variety of advantages, mainly including:
Production speed: die casting has significantly higher production speed than other processes and materials. This is due to the significantly reduced cooling of Zamak zinc alloy. Depending on the size of the casting, twice the speed can be achieved compared with aluminum or plastic. The hot chamber technology (Dina 5) developed by Minniti SRL allows up to 3500 times / hour (dry).
Energy saving: the relatively low temperature reduces the energy demand of Zamak process. Compared with aluminum, the energy saving is 15% compared with magnesium, and it is estimated that the energy saving is at least 50%.
Dimensional accuracy: Although the exact dimensions are mainly determined by the manufacturing process, the materials also affect the achievable tolerances. Compared with other three-dimensional processes, the manufacturing tolerance of die castings is smaller, and the dimensions are usually more accurate and consistent in extrusion, casting and wax loss casting. Alloy die castings can ensure compliance with tolerances, which may require molding with other materials.
Hundreds of tolerances can be easily achieved, while the tolerance value of aluminum is only one and a half and twice that of magnesium. Compared with aluminum and magnesium, zinc alloy is more stable in size. In addition, they usually require less control to be removed from the mold. In fact, parallel holes and exterior walls with a 0.5 ° projection can be obtained instead of the usual 2 °. The hole can be made of such a small cone so that the thread can be tapped directly.
Easy assembly: when necessary, the high ductility of zinc alloy (Zamak) allows the insertion of bendable, hammered or threaded castings to facilitate the assembly of other adjacent parts.
Low die wear: zinc die castings can usually be used for more than 2 million cycles. Their life is the same as that of thermoplastic injection molding, that is, about ten times longer than aluminum die castings and usually longer than magnesium castings. The same mold can obtain similar items by adding removable and replaceable inserts to prevent the construction of new molds from being uneconomical. Each project must be carefully evaluated to ensure the best deployment of equipment, so as to obtain a lower cost.
Safety: unlike aluminum, especially magnesium, Zamak will not cause fire risk due to sparks during the processing and use of castings.
Project complexity: die casting can be fully utilized by applying some basic design principles. The following points should not be considered mandatory, but if used with a grain of salt, it will help to create a cohesive, efficient and profitable project. Our extensive experience enables us to propose minor changes that may significantly affect the productivity savings of specific components.
Wall thickness: On the premise of ensuring strength and stiffness, the part of the wall must be as thin as possible
The most common size is 1mm, but it also has a thickness of 0.3mm.This helps to minimize the required metal weight and accelerate solidification in the mold, thereby increasing production speed.
Sharp angles shall be avoided as far as possible.
Internal joints are essential, and it is usually important to have a joint at the closed internal and external corners. A 0.5 mm joint will have a significant enhancement effect and will be almost unnoticed, as well as at the edge. There are very few geometries that die casting cannot achieve. However, inserts and other features that require the use of in mold removable elements increase the total cost. Internal indentation is subject to certain restrictions.
Face
Large planes should be avoided as much as possible. If necessary, slight bending can improve the appearance and roughness, which helps to avoid small surface defects affecting the overall appearance.
Thread
External threads are easy to obtain, especially when they appear on the parting line. Internal threads can also be molded, but it is usually more convenient to tighten the holes obtained by die casting. Alternatively, self tapping screws can be used.
Surface coating
Zinc alloy (Zamak) casting is the most direct and sometimes the most economical method for manufacturing precision and solid parts for a wide range of industries. Many products are used in technologically advanced applications that do not require surface treatment. However, in some cases, the coating needs to:
Obtain decorative effect
Improve corrosion resistance
Improve wear resistance and wear resistance.
The range of zinc alloy die casting is very wide, and new finishing processes are constantly studied and developed.
Chemical coating
Chemical resistant coatings provide corrosion resistance at low cost. They are obtained by immersion or, in some cases, by spraying components with a specific solution. There are two main types of chemical coatings, chromate conversion coatings and phosphate conversion coatings. In addition to corrosion protection, they also provide a basis for the continuation of organic coatings. There are also colored coatings that can only be used in low aggressive environments and / or components with little treatment. The special anodizing process transforms the zinc surface into a tough corrosion protective film. These coatings have a single functional use and are usually matte olive green.
Organic coating
The polished zinc die cast surface has a good appearance and can be maintained by applying an organic coating. These are clear and colorful acrylic / polyurethane varnishes or polyester powders. Painted or powder coated die casting is used for automobile, household appliances and general mechanical parts. In the process of electrolytic coating, the part to be painted is immersed in the basin (anode) containing special coating and soluble resin like the cathode. In addition to the advantages of uniform deposition film, the process does not require volatile and flammable organic solvents. Electrostatic powder coatings are increasingly used as coating die casting methods. After degreasing (chromium plating where maximum corrosion resistance is required), the parts are electronically sprayed, usually using heated polyester or epoxy powder to "dilute" the powder to obtain a strong film protective adhesive. Epoxy coating provides the best corrosion resistance, while polyester coating provides greater strength.
Electroplated coating
Zinc die casting parts can be surface treated with different types of electroplated coatings to achieve aesthetic or protective purposes, or to achieve special electrical or surface characteristics. For aesthetic and electrical and electronic surfaces and in some cases for easy welding, it is recommended to use a copper coating at the end. Copper deposits are also used as the basis for other types of coatings. The commonly referred to "chromium plating" is actually a coating composed of one or more layers of copper, one or more layers of nickel and one layer of chromium.
Another common surface treatment is nickel plating.
Anti friction characteristics: zinc alloy has good self-lubricating characteristics and has been used to manufacture parts with specific characteristics for many years. They are good substitutes for brass, especially for parts bearing small loads.
Anti vibration and noise reduction characteristics:
The damping capacity of Zamak at ambient temperature is between 2% and 4%. This value is higher than 0.5% for aluminum and 1.5% for steel. Only gray fonts have higher values, about 7-15%. Compared with aluminum, Zamak also has great absorption capacity.
Good operation of tools and machines:
Zinc die casting allows the use of different technologies to design complex parts, which will require more expensive machining. However, if any other process is required, the part can be easily machined using basic tools.
The precision level achieved by zinc alloy die casting almost completely eliminates the need for plane milling or grinding directly generated by die casting. However, in some cases, hollow parts may need milling and grinding.