of these composites,such as the densification (formation of the matrix)are long and delicate.These make the products very onerous.Applications include missile and launcher nozzles,brake disks,ablative tiles for reentry body of spacecraft into the atmosphere. 2.2.5 Cutting of Fabric and Trimming of Laminates Some components need a large number of fabric layers (many dozens,can be hundreds).For the small and medium series,it can be quite expensive to operate manually for following the form of a cut. respect the orientation specified by the design (see Chapter 5) ■minimizing waste. There is a tendency to produce a cut or a drape automatically with the following characteristics: a programmed movement of the cutting machine a rapid cutting machine,such as an orientable vibrating cutting knife or a laser beam with the diameter of about 0.2 mm and a cutting speed varying from 15 to 40 meters/minute,depending on the power of the laser and the thickness of the part. Example:With a draping machine MAD Forest-Line (FRA),the draping is done in two steps by means of two distinct installations: A cutting machine that produces a roller to which the cut pieces are attached (cassettes) A depositing machine which uses the cassette of cut pieces to perform the draping. The two operations are shown schematically in Figure 2.16. 2.3 PRACTICAL HINTS ON MANUFACTURING PROCESSES 2.3.1 Acronyms To describe the modes of fabricating the composite pieces,the professionals use many abbreviations.Each is detailed below,with reference to the paragraph number where the process is explained. B.M.C.:"Bulk Molding Compound."Matrix:resins.Reinforcement:cut fibers;additional fillers(powder).Pressure:5-10 MPa.Temperature:120- 150°C. Centrifugation:Matrix:resins.Reinforcement:cut fibers,mat,fabrics;see Section 2.1.7. 2003 by CRC Press LLCof these composites, such as the densification (formation of the matrix) are long and delicate. These make the products very onerous. Applications include missile and launcher nozzles, brake disks, ablative tiles for reentry body of spacecraft into the atmosphere. 2.2.5 Cutting of Fabric and Trimming of Laminates Some components need a large number of fabric layers (many dozens, can be hundreds). For the small and medium series, it can be quite expensive to operate manually for
following the form of a cut.
respect the orientation specified by the design (see Chapter 5).
minimizing waste. There is a tendency to produce a cut or a drape automatically with the following characteristics:
a programmed movement of the cutting machine
a rapid cutting machine, such as an orientable vibrating cutting knife or a laser beam with the diameter of about 0.2 mm and a cutting speed varying from 15 to 40 meters/minute, depending on the power of the laser and the thickness of the part. Example: With a draping machine MAD Forest-Line (FRA), the draping is done in two steps by means of two distinct installations:
A cutting machine that produces a roller to which the cut pieces are attached (cassettes)
A depositing machine which uses the cassette of cut pieces to perform the draping. The two operations are shown schematically in Figure 2.16. 2.3 PRACTICAL HINTS ON MANUFACTURING PROCESSES 2.3.1 Acronyms To describe the modes of fabricating the composite pieces, the professionals use many abbreviations. Each is detailed below, with reference to the paragraph number where the process is explained. B.M.C.: “Bulk Molding Compound.” Matrix: resins. Reinforcement: cut fibers; additional fillers (powder). Pressure: 5–10 MPa. Temperature: 120– 150∞C. Centrifugation: Matrix: resins. Reinforcement: cut fibers, mat, fabrics; see Section 2.1.7. TX846_Frame_C02 Page 24 Monday, November 18, 2002 10:40 AM © 2003 by CRC Press LLC