German foundry turns to air impulse molding system for upgrade. (Case History).

The Laubach, Germany-based Friedrichshutte is one of the oldest foundries still operating in Europe. Established in 1707, it became part of the firm Romheld GmbH in 1870. Today, the jobbing foundry specializes in low volume gray and ductile iron cast components for a variety of markets.

After extensive research into customer needs over the last five years, Friedrichshutte decided that it required an upgrade of its molding technology to achieve the necessary quality levels required by the marketplace as well as to reduce costs in both molding and cleaning to ensure competitiveness in the global arena. The foundry turned to Foundry Automation, Spresiano, Italy, for a solution, The molding system manufacturer decided its Adiabatic-Plus molding technology was the answer and provided Friedrichshutte with a new molding and mold handling system that has ramped up within the last year.

The new molding plant produces 70 molds/hr with flask sizes of 780 x 580 x 220/220 mm. The molding system utilizes the air impulse compaction process in which air pressure from 3-5 bar/sec is used during mold filling to fluidize the sand grains and allow each to slide over one another to ensure homogenized filling of all the free space on each pattern. Only through proper fluidization can efficient air impulse compaction be achieved. Once filled, the mold is subjected to up to a single 600 bar/sec air impulse for mold compaction, Through this compaction process, mold hardness is highest at the face of pattern, gradually decreasing towards the outside of the mold. This increases the mold's permeability to gases generated during casting, reducing or eliminating the need for venting.

Another advantage of this air impulse compaction is the ability to concentrate the energy peripherally or centrally in one portion of the mold. For example, if a deep pocket exists on the pattern, compaction energy can be concentrated to achieve efficient mold hardness with tight corners at the pocket to reduce casting cleaning costs. In addition, the molding system employs suction beneath the pattern during mold filling/sand fluidization to eliminate air cavities in the mold.

The molding system at Friedrichshutte is able to utilize wood and plastic patterns because of less wear and tear with air impulse compaction. The patterns only needed to be attached to multi-layer wood pattern plates. During mold production, the patterns are accessible to allow for the insertion of insulated riser sleeves.

The manufacturer also developed the mold handling system for the foundry, including seven core-setting stations. The entire mold system is controlled by the manufacturer's software system that ties production data to the foundry's engineering office.

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