aluminum die cast medal
Aluminum high pressure die casting process can achieve very precise and intricate product. Thus it can be used to cast somewhat art products. Besides,aluminum alloy has bright appearance and somewhat heavy metal feeling; it will be much more impressive with some surface treatment like nickel plating or chrome plating which can make the aluminum like stainless steel shiny and beautiful compared with much low production cost.
The aluminum die casting medal is a school medal for an american university. The design is much impressive,as it has much casting difficulty. Like common part,we added draft angle to the 3-d pattern for the customer's approval. The 0.5 degree angle in the drawing direction won't affect the appearance of the casting medal a lot. But for some casting edges, customers insisted that the rounds be not allowed. That is to say, some sharp edges should be obtained by the die. As we know, sharp edges on the casting are subject to crack. Herewith we need use special tooling steel for the cavity.
The raw casting design was confirmed, after a further discuss with the customer. The die casting mold was prepared quickly. During the mold production, there are two critical steps should be focused. As the finished medal asked for very shiny and smooth surface, so the mold cavity should be polished well, and the parting surfaces should be matched precisely. Fortunately, the parting line was located successfully with assistance of computer analysis.
The die casting mold was ready after 25 days. In order to achieve fine raw casting, we chose 280 tons of hot chamber die casting machine to cast the product. Besides, we had applied powder lubricant for picking out the work piece,which can prevent the surface from oil and grease spot.
The casting samples were quite satisfying. The surface was smooth without any crack and oil spot. Even the parting line was slightly on the product edge. All that reduced post trimming works. We just cut off the gate system for the raw casting then forwarded them to the polishing workshop.
The casting work piece should be mirror polished.Our polishing workshop met a trouble with the so much planes with different height in the same side. The polishing wheel can be fixed to the certain plane hardly without touching the other planes. The sharp edges of the planes were always damaged while polishing other planes. Thus the mirror polishing step resulted into very high rejection rate as 30%.
The mirror polished castings were chromate for degreasing and cleaning before lacquering. The final step was processed nearly all by machines. Only expect we reject some lacquered work piece with bubble in the surface, the largest portion of the products were quite satisfying.
Here we recommend the customer to apply nickel plating or chrome plating for the casting medal. The effect must be much more impressive than that with polishing and lacquering,though of cause the electroplating will rise production cost a lot.
