Braiding machine

In the past a limitation on this process was that it tended to be restricted to shapes which were symmetrical about an axis of rotation and from which the mandrel could be easily extracted. However, in recent years there have been major advances through the use of collapsible or expendable cores and in particular through the development of computer-controlled winding equipment. The latter has opened the door to a whole new range of products which can be filament wound - for example, space-frame structures. Braiding machines for complex shapes are shown in Fig. 4.76. 

Braiding hoses with wires to resist high burst pressures or for external protection is common, using a braiding machine. The wires used, usually of steel, will be either zinc- or brass-coated to achieve adhesion during vulcanisation. The gauge of the wire and its tensile properties will be matched to the expected service demands for the hose. 

The bobbins of the braiding machine are loaded with the appropriate number of wire filaments to achieve the desired structure. 

Braiding machines are of two basic types vertical and horizontal and both find application depending upon the type of hose being manufactured. 

Figure I 5.5 Schematic of a braiding machine, seen from above— the black bobbins circulate anticlockwise, while the grey ones circulate clockwise. The strands are drawn off towards the viewer and braid around the central core.

One of the desired features of the technical plant stem is improved torsional stability and oscillation damping. As mentioned, the diagonal fiber bundles can be incorporated into the technical plant stem via a braiding machine, which was installed in-line with the pultrusion process (Figs 9.13 and 9.14). 

Potluri P, Rawal A, Rivaldi M, Porat I. Geometrical modeling and control of a triaxial braiding machine for producing 3D preforms. Composites Part A 2003 34 481-92. 

In many ways, braiding can be compared to filament winding, but cannot achieve such high volume fractions in a composite. A braid is a system of three or more yarns intertwined such that no two yarns are twisted around one another. Braiding machines can be made with... 

Figure 21.27 A typical flat braiding machine and diagram of braid construction. Source Reprinted with permission from Ko FK, Braiding, ASM International, Metals Park, 519-528, 1987. Copyright 1987, ASM International.

A dry fiber preform is used with the layers of fibers/fabric holding it together with a powder binder. This initial preform is consolidated under heat and pressure to form a rigid preform, which is then placed in the blade mold and a core of low density polyurethane foamed in situ, followed by applying layers of carbon fiber at 45° using a braiding machine. 

Carrier n. (1) A product added to a dye bath to promote the dyeing of hydrophobic manufactured fibers and characterized by affinity for, and ability to swell, the fiber. (2) A moving holder for a package of yarn used on a braiding machine. (3) A term sometimes used to describe the tube or bobbin on which yarn is wound. Tortora PC (ed) (1997) Fairchild s dictionary of textiles. Fairchild Books, New York. 

In addition to the hom-gear braiding machine, Cartesian braiding and rotary braiding are commonly used to fabricate 3D braided stmcture. These mainly differ in their yam carrier actuation system and the corresponding movements of yam carriers on the braiding loom. 

In 3D rotary braiding machines, multiple hom-gear units are assembled on the braiding loom in certain configurations of rows and columns. To achieve flexible yam carrier movement, each horn gear may be controlled individually. Depending on the... 

Often it is required to produce a preform with a changing cross section along the braid length on a track-and-column braiding machine. Limited research has been performed on this currently. However, one method to produce a braid with varying cross shape is introduced here based on the UM of braiding. 

Figure 7.18 AYPEX braid machine loom setup (Huey, 1994).

Huey, C., 1994. Shuttle plate braiding machine. US Patent US5301596 A. 

---