13.Molding and Casting

This week I decided casting a statue that I printed with 3D printer. This statue was the pattern for metal statue that I want cast. As it was te first time and testing version I download existing model of statue. Sand casting is a casting process by which sand is used to create a mold, after which liquid metal is poured into this mold to create a part. The first step in the sand casting process involves fabricating the foundry pattern – the replica of the exterior of the casting – for the mold. These patterns are often made from materials such as wood or plastic and are oversized to allow the cast metal to shrink when cooling. They are used to create the sand mold for the final part, and can potentially be reused depending upon the pattern material. The second step is the process of making the sand mold(s) from these patterns. The sand mold is usually done in two halves, where one side of the mold is made with one pattern and another side is made using the other pattern. The top part of the mold is known as the “cope” and the bottom half is the “drag”, and both are made by packing sand into a container (a “flask”) around the patterns. The operator must firmly pack (or “ram”) the sand into each pattern to ensure there is no loose sand, and this can be done either by hand or by machine. After ramming, the patterns are removed and leave their exterior contours in the sand, where manufacturers can then create channels and connections (known as gates/runners) into the drag and a funnel in the cope (known as a “sprue”). These gates/runners and sprues are necessary for an accurate casting, as the runners and gates allow the metal to enter every part of the mold while the sprue allows for easy pouring into the mold.

Frying pan molding and casting.