Custom Zinc Die Casting

Causes of blistering defects during custom zinc die casting:
Zinc alloy die castings are now widely used in various decorative parts, such as furniture accessories, architectural decoration, bathroom accessories, lighting parts, toys, tie clips, belt buckles, various metal buckles, etc. Therefore, high quality requirements are required for the surface of zinc alloy die castings, and excellent surface treatment functions are required. The most common defect of zinc alloy die castings is blistering on the surface.
Characterization of Blistering Defects in Zinc Alloy Die Castings
There are raised vesicles on the surface of zinc alloy die castings, mainly in the following three aspects
(1) Found after die casting.
(2) Exposed after polishing or machining
(3) Presented after oil spraying or electroplating.

Zinc alloy die-casting foaming defect occurrence factors
1. Holes in zinc alloy die castings
The holes in zinc alloy die castings are mainly air holes and shortening holes. The air holes are often round, and the shortening holes are mostly irregular.
(1) Causes of shrinkage cavity: During the coagulation process of molten metal, shrinkage cavity occurs due to the volume reduction or the lack of metal liquid feeding at the final coagulated part. Zinc alloy die castings or zinc alloy die castings with uneven thickness are somewhat Overheating will cause a certain part to coagulate slowly, and the surface will form a concave position when the volume shrinks.
Due to the existence of pores and shrinkage cavities, water may enter the holes during the surface treatment of zinc alloy die castings. When baking after spraying paint or electroplating, the gas in the holes will expand due to heat, or the water in the holes will become steam. Swelling, thus causing blistering on the surface of zinc alloy die castings.
(2) Causes of porosity: During the filling and coagulation process of the metal liquid, due to gas intrusion, holes appear on the surface or inside of the zinc alloy die-casting; out. When the gas in the cavity, the gas released by the evaporation of the paint, and the gas separated by the condensation of the zinc alloy, some of them remain in the zinc alloy die-casting to form pores when the exhaust of the zinc alloy die-casting mold is poor.

2. Intergranular corrosion of zinc alloy die castings: harmful impurities in zinc alloy components such as lead, picks, and tin will meet at the junction of grains to cause intergranular corrosion. , the part affected by intergranular corrosion will expand and the plated roof will be raised, forming blisters on the surface of zinc alloy die castings. Especially in a humid environment, intergranular corrosion will deform, crack, or even break zinc alloy die castings

3. Cracks in zinc alloy die castings: cracks in zinc alloy die castings include hot cracks, cold cracks, and water.
(1) Hot cracks, when the thickness of the zinc alloy die casting is uneven, stress occurs during the agglutination process; premature ejection, the metal strength is not good, and the force is uneven during ejection; too high mold temperature makes the grain coarse and harmful impurities exist , Zinc alloy die castings have water marks, cold barrier marks, and hot cracks. The melt will enter the cracks during electroplating, and it will be converted into steam during baking, and the air pressure will lift up the electroplating layer to form blisters.
(2) Water marks and cold barrier marks: During the flow pattern process of the molten metal, the contact wall of the molten metal that enters first condenses prematurely, and the molten metal that enters later cannot be fused with the condensed layer, and it is docked on the surface of the zinc alloy die casting Moiré lines are formed at some places, showing strip-shaped defects. Water lines are usually shallow on the surface of zinc alloy die-castings, while cold-separated lines may enter the interior of zinc alloy die-castings.

Our customers benefit financially by purchasing precision OEM parts from us, such as iron/steel/aluminum castings, sheet metal parts, aluminum extrusions and CNC machined parts, injection molded parts.
You can customize a variety of plastic or metal parts, from prototypes to final products. Give us a concept and we will return to you with a product that we look forward to serving you in the near future.

Hot Tags: custom zinc die casting, China custom zinc die casting manufacturers, suppliers, factory