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how it’s relevant to them,” Brown said. “You don’t want to be in a situation where you’re engineering the casting. What you’re there for is castability and to make the part they want, and they are the ones setting the technical speci- fications for liability purposes.” If a casting is over specified or the


customer is choosing between different grades of iron, for example, the met- alcaster can demonstrate the proper- ties of various alloys up close and in person. Seeing the castings made also helps the supplier overcome the chal- lenge of product design mistakes. “It shows them the wonder of draft,”


A recent MCDP survey of 79% of U.S. metalcasting plants showed most facilities use mul- tiple processes, with horizontally parted green sand being the most popular. Iron is the second most used material, after aluminum, at 31%.


customer get more than 10% of our capacity, and no industry more than 15-20%. Presently our top customer is at about 5.5%,” he said. Te company is serving its existing


customers with larger volumes, expand- ing its existing customer base and taking on new work, primarily in ductile iron. “Ductile iron is much easier to sell at


present,” Brown said. “Where we tradi- tionally were more gray iron than ductile iron, we’re seeing the ductile iron at about a 2:1 increase. Ductile is much stronger than gray and has more applications than gray. But in certain applications, gray is more acceptable than ductile iron.” While gray iron metalcasters outnumber those supplying ductile iron castings, MCDP’s 2012 Casting Source Directory shows a majority of iron metalcasters offer both types. Brown noted that pouring ductile iron requires technical quality controls that are outside the scope of some facilities. “At this present time, you probably


have to be in the $3.5 to $5 million sales range to be technically relevant in [the ductile] market going forward. With [lower] sales, it’s difficult for you to take your bottom-line profits and buy a $1 million molding machine or a $250,000 core machine, because the


profits aren’t there. So that’s where I see the real shortage on the jobbing side,” said Brown. “If I were to pick a very comfortable portion of the market, it would be to have a low-volume ductile iron foundry that could make castings between one and 500 lbs., because there is a definite lack of capacity.”


Planning Better Castings Benton’s casting experts spend


a significant amount of time educating customers on how castings are made and what is needed to optimize production. It’s important for designers to bal- ance the desired part characteristics with process requirements, such as draft, and the limitations or additional capabilities of the type of molding equipment. Casting process simula- tion programs can help, but seeing the material properties demonstrated in person often drives home the neces- sary points. Benton invites customers in to spend a day or two in the facility, walking through the process of making castings, ideally one of their own. “Tey’re making the core, pouring


the iron, cleaning and grinding, then taking it back and having test bars pulled out of it. So they can see the process from beginning to end and see


38 | METAL CASTING DESIGN & PURCHASING | Sept/Oct 2012


said Brown. Draft is the taper on the vertical sides of a pattern or corebox that permits the core or sand mold to be removed without distortion or tearing of the sand. “[Inexperienced design- ers] might want to put the part number on the side of the casting. Well, that’s not going to draw in the mold, so that means the part number has to be made in a core, and when you show them what draft does and how it works, because it’s not something you find in CAD easily, then a light goes on.” In one case, a designer realized a tooling simply needed to be turned around, accomplishing a 30% price decrease as fewer cores were required to make the piece castable. Benton uses the same equipment for


both types of iron and can move jobs from one production line to another eas- ily. Te facility makes 97.5% of its molds on automatic molding machines. “We have a number of different


sizes of [equipment from] the same suppliers. It helps us standardize on spare parts, and we follow the Noah theory that we have two of everything on the ark,” Brown said. With capacity tight across the


board, U.S. metalcasters are coopera- tive when it comes to moving jobs to facilities that are better suited to pro- duce them. “Te industry as a whole is fairly informative in what needs to be in place for the job to be a good fit for the foundry,” Kuehnel said. Te key for designers and purchasers is to seek production information and casting knowledge from their sup- pliers, to ensure a job is planned well from the beginning. 


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