SELECTING EQUIPMENT
Some questions to consider when choosing automation melt transfer technologies include: • What volume of castings will be poured? Is the volume consistent job to job, or will it vary?
A covered launder system serves several casting machines.
• What is the part weight? How much metal is needed? Does the part size and pour weight vary significantly?
• How far is the mold or pour location from the furnace? What is the time and distance of travel?
• Is flexibility in alloy, fill rate, and shot size an issue? What is the required time of change between different molds or alloys?
dents indicated it was a primary melt transfer method. Dosing furnaces can deliver highly repeatable temperature and shot profile control and are closed systems, making them energy effi- cient. Tese benefits come at a higher initial purchase cost. Like many of the other melt transfer systems, they can be engineered for specific shop floor layouts and applications. Pumps are versatile and provide
good shot profile control. Tey can be adapted to a variety of furnace styles and metal filtering options. Con- straints include a limited shot size and difficulty accommodating longer reach applications.
Launder Systems Nine percent of survey respondents
indicated launder systems were used, but none said it was their facility’s primary melt transfer method. Molten aluminum can be moved a great distance in a facility through launder systems. Te systems do not require any moving parts, provide excellent temperature control (when used with covers) and incorporate in-line filter- ing and metal treatment options. Tey are relatively low maintenance and can provide a safe and comfortable work- ing environment. Launders take up a lot of floor space and can restrict floor movement. Tey are typically appli- cable to single alloy shops.
Bottom Pour Stopper Rod Among the surveyed respondents,
the bottom pour stopper rod method was not indicated as a primary melt transfer method. Te units come in a wide variety of styles, sizes, capaci- ties and uses. Because they are closed to the atmosphere, the ladles help minimize oxide formation and provide cleaner metal with minimal tempera-
August 2012 MODERN CASTING | 39
• What is the effect of the equipment on metal quality? • Will the guarding on the most automated system inhibit core placement or mold maintenance?
• What are the cost factors (equipment and installation) of consumables such as ladles?
• What is required for maintenance and operating technical requirements? • What safety requirements are involved? • What is the speed of the method? • What type of metal quality is expected from using the chosen method?
ture loss. It can be difficult to control the pour profile using a stopper rod, and the unit occasionally drips metal. Te refractory ladle material is some-
what fragile. Stopper rods also can be used with automatic ladle equipment, robots or mounted to an overhead powered bridge crane.
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