Surface finishes
A variety of high quality surface finishes is another major advantage
Electro-Plating
Zinc die castings offer excellent plating characteristics. Electro-plating is generally a multi-layered coating consisting of one or two copper layers, one or two layers of nickel, and a final layer of chromium, brass, gold, or any other platable metal. Chromium plating is the most popular decorative finish when corrosion and high abrasion resistance are required.
Chrome plating adheres best to the ZAMAK alloys and ZA-8 followed by ZA-12. Chrome plating of ZA-27 is possible but more difficul due to the need to treat ZA-27 like an aluminum casting. Processes which provide a smooth, dense outer skin such as pressure die casting and permanent mold casting are preferred when plating is being considered.
Chromates
Chomating is a low-cost chemical treatment that provides additional corrosion protection against « withe rust ». This form of zinc corrosion is caused by prolonged exposure to damp conditions. Chromate finishes are produced by simple dip methods which deposit a thin chromate coating. Chromate coatings are often applied to instrument, military and automotive components where low cost resistance to moisture is required. These coatings normally have a bronze tone or metallic lustre depending on the process used.
Phosphates
Phosphate coatings are primarily used to provide a good base for painting or powder coating.
Anodizing
A special zinc anodizing treatment is avaliable for zinc castings. This coating is completely different than that for aluminum alloys. Zinc anodizing is a functional coating providing maximum corrosion resistance in atmospheric and marine environments.
Since the process uniformly coats deep recesses and threaded areas, anodized zinc alloy casting can serve as an economical alternative when replacing traditional brass, bonze and stainless steel components.
Polishing and Brushing
Conventional high lustre polishing or brush finishing techniques can produce appearances similar to chrome plating or stainless steel. When lacquered, these finishes are suitable for decorative, interior applications.
Painting
All zinc alloys form an excellent base for paints. To aid paint adhesion, phosphate or chromate pretreatments are often employed. Zinc alloys can also be elctrostatically painted.
Powder Coatings
Powder coating involves electrostatic spraying of the zinc castings with an epoxy or polyester powder. The parts are then immediately oven cured for a hard dureble finish. The result is an even, inexpensive, corrosion resistant plastic coating. Powder coatings are avaliable in a wide range of colours.
Source : Interzinc
Zamak in jewelry
As you know there are many types of materials for jewelry pieces . But today we pay attention to one in particular that has shown great results , come and compact shape , so that we can acquire and simply add it to our room. We speak of Zamak .
And what is the zamak ? You see, it is a material made from zinc alloy , aluminum, magnesium and copper. It is hard and tough, and can be found in lots of ways for your beads.
Ideal for jewelry because with the passage of time is not damaged, you may lose some luster but does not deteriorate or is aged with use unlike other materials. Compared to silver, Zamak besides being cheaper is not dirty with use. And compared to metal, Zamak no breaks or gets ugly with the passage of time, is lighter than steel and almost has the same resistance. This does not mean that there do not care for it, but it is more durable and attractive than other materials.
Source : abedulart
Numerical simulation of filling pressure casting
Foundry under pressure, a system of effective and well-designed diet provides a proper filling of the room, health room corresponding to the specifications of the client and does not degrade some mold elements (collage, erosion) while providing a time cycle and minimum downtime (TRS). Various tools exist to make possible the more optimized design and require a minimum of development and changes during initial testing of mold production.
Role of the feeding system
A supply system must:
- To evacuate air from the cavity as far as possible
- Easy to fill all areas of rooms
- Able to transmit the pressure multiplication (P3) massive areas or sensitive
- Completing parts (multi-cavity cluster) in the same manner
Design rules
- Length of the longest possible attack (for permetttre a short filling time and avoid excessive speed attack)
- Have massive attacks near areas
- Limit the number of attacks (not contiguous) each to prevent uncontrolled flow of metal
- Thickness sufficient to transmit P3 attack while ensuring easy cutting
- Avoid attacking in front of small pin uncooled (collage) close attacks casting particular
- Adapt sections of attacks in different areas to fill
- Ensure sprayed attacks flow to disperse the best porosities
Tools
- Experience feedback (REX) and know-how on previous designs
- A business tool (Salsa 3D, developed by IWTC and sold by sold by ESI)
- Numerical simulation of filling (in-house or outsourced). IWTC performs many optimizations initials or by numerical simulation of mold designs for the founders and principals.
Source : CTIF
Source : My little blog fonderie
The advantages of zinc casting alloys
TODAY´S ZINC CASTING ALLOYS are strong, durable and cost effective engineering material. 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, and choice of casting processes make zinc alloy the unquestioned material choice for the 1990´s, because they´ll save you time and money:
Assembly operations are reduced
Entire assemblies can be cast as a single unit, eliminating the need for expensive manual assembly operations.
Assembly operations are reduced
Entire assemblies can be cast as a single unit, eliminating the need for expensive manual assembly operations.
Less material in 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
Due to the superior net-shape casting capability of zinc alloys, machining can be eliminated or drastically reduced.
Faster production and extended tool life
Die casting production rates for zinc are much faster than aluminum, or magnesium. Coupled with a tool life often exceeding 1 million parts, tooling and machine usage charges are dramatically reduced.
Eliminate bearings and bushings
Zinc´s excellent bearing and wear properties allow greater design flexibility and reduce secondary fabrication costs by eliminating small bushings and wear inserts.
Choice of low, medium and high production
A variety of casting processes are available to economically manufacture any size and quantity required.
Source : Interzinc