|The Vibra-Drum’s natural-frequency vibration produces a rotary motion of the sand and casting bed that breaks lumps, cools and moisturizes sand, and cleans sand from the castings without causing them damage. |
Modern foundries have many shakeout options. Improper selection can lead to poor throughput, damaged castings, and unnecessary downtime, all which costs the operation time and money. Among the designs available are brute force, variable drive, and two-mass high-frequency vibrating shakeouts, vibratory drums, and rotary shakeouts. Each is particularly suited to a specific casting style and metallurgical type.
The two styles of vibratory shakeouts are brute-force and two-mass. The simpler of these, brute-force shakeouts, are basically a steel box or trough with a perforated surface and unbalanced drives attached to impart force to the machine. Force is transmitted into the mold to break the sand from the casting. These systems have limited applications, because of significantly higher horsepower requirements.
Adding electronic process controls to brute-force shakeouts allows the angle of attack to be varied in the vibration. General Kinematics’ Vario-Drive™ uses these controls to speed up, slow down, or completely stop horizontal travel of material on the shakeout body. So, the operators can retain the casting on the shakeout deck as long as needed to ensure complete sand removal. Both standard and variable-angle brute-force shakeouts work well in foundries with low mold counts, as a delay is required between molds to achieve the proper retention and shakeout time.
Two-mass high-frequency shakeouts advance the brute-force concept. Using a two-mass natural-frequency spring system between the drive and the shakeout body, two-mass units impart a high-frequency impact force into the casting with minimal horsepower and energy requirements. Machine stroke is adjustable on two-mass shakeouts, so they are adaptable to any shakeout situation, and are ideal for high mold-volume facilities.
Vibratory drums are optimal for no-bake, brass, and all other foundry applications where reduction or elimination of casting damage is necessary. Benefits of the non-rotating, totally enclosed design include easier dust collection and air system attachments, the ability to add peripheral attachments such as water addition, and for mating auxiliary equipment to the drum. Vibratory drums, like the GK Vibra-Drum®, deliver high-capacity throughput and superior material motion for efficient sand and casting processing. The Vibra-Drum’s natural-frequency vibration produces a beneficial drum-like rotary motion of the sand and casting bed that quickly reduces sand lumps, cools and moisturizes sand, breaks down lumps, and cleans surface sand from castings without causing the castings to tumble on each other. Castings and sand are discharged onto a vibratory screen to separate processed sand from the castings quickly.
Rotary drums are a simple, cost-effective way to process castings in all types of foundries. However, they tend to lift and drop castings, which can damage them and increase scrap rates. They are common in ductile-iron foundries, where they help to limit the amount of manual labor required to de-gate castings and to reduce tangling of castings and sprue.
Innovations in rotary technology, such as GK's new Ducta-Series rotary drums, allow ductile foundries to process castings effectively without the typically high maintenance costs found in older rotary designs. The key to the Ducta-Series™ is the fabricated A/R liner systems, which are easy and safer to replace, and can be customized to meet customers’ specific throughput and sand-removal requirements.
Rotary drums are designed to perform specific processes. Drums such as the Ducta-Sprue® are engineered to clean and break up sprue quickly for cleaner recycling. The Ducta-Screen® rotary shakeout breaks apart molds, separate sand, and remove sprue and gates from castings. Media drums, including the Ducta-Clean®, use media to clean ductile iron castings prior to the blast process while removing mold and core sand.
Throughput, casting metallurgy, and casting design are among the many options to consider when selecting a system that will offer the highest level of satisfaction and payback.