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IMPROVING GRID CASTING PRODUCTIVITY
Improving Grid Casting Productivity through the number of acceptable grids produced in a given period of time can be accomplished in several manners.
Obviously if the equipment is very old and inefficient the first consideration should be in replacing with newer pieces of equipment incorporating the latest improved features. However, the following suggestions are an approach to improving existing installations.
The first area to be considered is mold heating; unless electric mold heat is currently being used, consideration should be given to a conversion from gas heating to electric heating. Assuming that the lead pot temperature is correct for the type of alloy being used, and the feedline and ladle temperatures are reasonably controlled, then the electric mold heat with automatic controls will help mold filling, allow for a faster casting cycle and result in longer casting runs per cork job. Electric mold heat kits are available and include lower zone heating on the front and back half of the mold. The kit includes heaters and necessary components partially assembled for ease of field installation.
The next item to consider is the mold cooling system, since variations in the water temperature being used for the cooling of the gate and center mold sections can have adverse effects on the mold filling and the casting cycle. A re-circulating cooling system equipped with controls to re-circulate the coolant and maintain a constant temperature of the fluid aids in maintaining a more uniform temperature in the mold. Controlled cooling can improve production speeds, permit lighter weight grids to be produced and reduce mold maintenance.
The mold itself is a major item to consider. Wirtz patented vented style molds permit much improved filling. When used with a good cooling system and electric mold heat the vented molds provide easier filling (thru better venting), lighter weight grids, and longer runs on a cork job. They also provide the capability of uniform control of grid size and weight. Center water cooling will eliminate cracked grid frames in center of the mold and allow speeds up to approximately 16 casts per minute.
Mold coating technique and the type of mold coat material being used is important in maximizing the grid production. Detailed information on corking technology, spraying technique and mold coat materials are available through Wirtz information bulletins.
Older casting machines may not have adequate grid handling mechanisms to accommodate the softer alloys and higher production rates. Consideration may be given to a machine conversion kit which includes the Wirtz patented die entry mechanism and necessary parts prepared for field installation. The mechanism provides improved handling of the grid from the mold to the trim die, reducing grid damage and resultant loss of production.
Finally, a lead delivery system with full automatic temperature controls to reduce dross build up may be considered. Refer to Wirtz information bulletin L-7.
Casting departments vary greatly and may utilize machines of varying ages and types with different stages of technical development. Therefore, requirements to improve productivity will be different. We will be pleased to provide specific information on your particular needs. Please forward as much detailed information as possible for our technical staff to prepare recommendations.
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