A new state-of-the-art facility for casting turbine engine parts and components was unveiled last December in Tampa, FL, and members of the aviation maintenance media were there.
Chromalloy is a worldwide supplier of large gas turbine engine critical gas path (hot section) blade and vane repairs and coatings, and also a manufacturer of replacement hot section components approved by the FAA under a Parts Manufacturer Approval. In addition to aircraft turbine engine parts, the facility also produces the same types of parts for industrial gas turbines found in the power generation industry, marine, and other heavy industrial applications. Both the aircraft and commercial industrial parts are all subject to the same high-standards and follow the same manufacturing processes.
The company invested $30 million into this 115,000-square-foot facility. Tom Trotter, vice president and general manager of Chromalloy Castings, says, “This was a clean-sheet design and throughout the facility process flow was designed into the floor plan and lean manufacturing techniques were considered with every process. This facility is designed to pour up to 1 million pounds of nickel and cobalt super alloys per year in a process known as “investment casting.”
According to Trotter, approximately 250 are employed at Chromalloy Castings, 30 in engineering or other technical specialty roles, and the company has 12 Six-Sigma Black Belt individuals on staff. The new facility is within a 20-minute drive of the old facility which has been established in the Tampa area for 20 years. Approximately 90 percent of the existing work force was retained after moving to the new location. Trotter shares, “All of the employees are excited to be part of the clean-sheet design and everyone embraces the culture of continuous improvement. This is all part of how we are re-defining World Class.”
Investment casting as it was explained is an old process in which molten metal is poured into a ceramic mold. The mold is made by using a wax pattern in the shape of the desired part. This wax pattern is covered or “invested” in a slurry made from ceramic materials which hardens into the mold. Investment casting is sometimes referred to as “lost-wax casting” because the wax pattern is eventually melted out of the mold.
The investment casting process is typically used for casting metal parts having complex shapes with high melting temperatures such as turbine engine blades and is very precise. The most common metals used are aluminum alloys, bronze alloys, magnesium alloys, cast iron, stainless steel, and tool steel. Investment casting of turbine engine parts requires many types of equipment and technical processes, such as wax mold creation, ceramic slurry application, pouring molten metal, furnaces, autoclaves, cutting, grinding, sandblasting, inspection, measuring, and more.
The new facility
Our facility tour started near the Wax Department, which has a staff of 37 people all having more than 10 years experience in their jobs. Marilyn Breckley proudly says, “It all begins with the wax input. Cleanliness and housekeeping are most important and audits of the area are regularly accomplished to ensure we continually meet the standards set for this type of operation.” She went on to show some of the first steps involved with producing a wax pattern and the mold assembly for a first stage high-pressure turbine blade for a CFM56-3 series engine. The result forms the pattern used to cast a new blade.
The next stop on our tour was the Shell Building area. The Shell Team is comprised of 24 people; again all with many years of related experience. This is the “investment” stage. The shell is typically made of six to 10 layers of the ceramic slurry which has been applied around an assembly of wax molds on what is termed a mold tree. The shell is then cured in an autoclave under high temperature and high pressure.
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Casting seminar held at Chromalloy’s newest superalloy foundry in Tampa, Florida