Automated casting cleaning system for job shops improves Dotson's efficiency. (Case History).

For jobbing foundries, no greater obstacle may exist in production than the bottleneck that often forms in the cleaning room. Traditionally, this area of the foundry is extremely difficult to automate. At Dotson Co., a 120-employee gray and ductile iron jobbing green sand caster in Mankato, Minnesota, they have been looking for an automated solution to cleaning room headaches for years.

"I have been on a ten year quest to do something different in foundry cleaning rooms," said Denny Dotson, Dotson Co. president. "I have been trying to find a cost effective, automated system that would help solve our casting cleaning problems."

Manual casting cleaning is one of the most difficult jobs in a foundry and it is difficult to expect workers to perform consistently over an eight-hour shift. For similar difficulties in its sand and metal charging systems, Dotson turned to automation. For the jobbing foundry, casting cleaning was the next logical step.

For the solution, Dotson turned to Roberts Sinto Corp., Lansing, Michigan. The foundry, which casts jobs up to 100,000 parts/year, had been talking to the supplier about its cleaning problem, and the supplier mentioned that it was bringing a new grinding system

called the Barinder Grinding System over from Japan. Dotson employees went to visit the system in operation on a variety of different casting jobs at Japanese foundries. The foundry liked what it saw and purchased two systems. Shortly thereafter, the firm bought a third and established a cell operation in the cleaning room for the three machines in which one operator services (programming, inspection, and loading and unloading) all three systems.

The Barinder grinding technology utilizes robotic part handling and automated grinding wheels to remove gates, burrs and parting line fins on gray and ductile iron castings. In production, castings are loaded into the system and the grinder's robotic arm moves each part into the optimum position relative to the grinding wheels to expose both the exterior and interior of the casting. The main grinding wheel handles exterior part cleaning and a mini grinder attachment finishes internal cavities and other hard-to-reach areas, Both grinders perform in a repeatable manner not achievable with manual grinding.

For Dotson, the system runs 24 hours! day, seven days a week. This is a drastic change for a foundry that had jobbed-out its grinding work since the 1980s. According to the foundry, this grinding system and its efficiency is making it reconsider bringing all of its grinding back in house.

Programming allows the operator to teach the grinding system to automatically execute the same operation as manual grinding. For a part and tool changeover, casting holding fixtures can be changed in minutes with hand tools while the new part program is called upon, loaded and verified.

Dotson has programmed the grinding systems for nearly 100 different part configurations weighing from less than 1 lb up to 75 lb. These components include truck drive parts, brackets for diesel engines, and components for construction and machinery equipment.

Dotson also believes the grinding system presents opportunities in casting design. According to the foundry, when a component designer knows they can shift small part features from the molding process to the grinding process, they may have eliminated an obstacle that made the part a problem to cast. Or, they may have devised an alternative that will substantially lower part costs.

Select No. 036 at www.moderncasting.com/info