The newest model rotary media drum from Didion International Inc. is the MD-80, in the Mark 5 series, which performs shakeout, sand conditioning, double sand screening, casting cleaning, and casting cooling in a single step. The process also helps metalcasters keep their operations clean, because it reduces the volume of airborne silica dust.
For Bentonville Casting Co. in Bentoville, AR, there is the additional advantage of equipment scale. It replaced an earlier model Mark 5 drum with the MD-80, and now effectively cleans a wider range of its gray and ductile iron castings. The jobbing foundry produces castings weighing in the range from just a few pounds up to 550 lbs., from flaskless automatic green sand, cope and drag, and nobake molding.
In addition, the shakeout system separates core sand from green sand and discharges them independently at different points. Tramp metal and other debris are removed, too, and the return sand is blended and conditioned for temperature and moisture consistency.
"We can now run larger castings that were too big for the MD-50," explains Chris Hines, president of Bentonville Casting. "We have fewer new sand additions, as the machine double-screens the sand to 3/8 in., the sand quality is better with the core sand/tramp metal discharge option, and the castings are better protected with the increased media bed."
Another advantage from the Didion MD-80 is that it has ended Bentonville’s need to knock out cores by hand from the castings produced on its cope and drag line. With the new rotary drum, those castings can be handled together with the other products, and the cores are knocked out in the process.