Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Prepreg layer lamination

The purpose of this study is to develop a simple model which retains some of the features of the above complex process to predict the lay-up thickness as a function of time during the squeeze-flow lamination of circular prepreg lay-ups. The prepreg of interest is of the type commonly adopted in the board manufacturing industry. It is composed of two outer resin layers and a fabric core constructed of interlaced yarns oriented in two directions perpendicular to each other (Figure 1). The fabric core is treated as a porous slab characterized by a constant Darcy permeability coefficient (see k in Darcy s law% i.e.. Equation 2 below) which can be estimated from fabric parameters such as the yarn diameter and the pitch distances. The lay-up thickness predictions provided by this model have been found to be in reasonable agreement with experiment for the lamination of up to five epo.xy prepreg layers. [Pg.501]

Figure 2 Definition of parameters for the lamination of N prepreg layers. Figure 2 Definition of parameters for the lamination of N prepreg layers.
Single Prepreg Layer. For the sake of illustration, we shall first confine ourselves to the lamination of one prepreg layer for which the two resin layers are of equal initial thickness ( Ao Ai = A). [Pg.504]

Given k and tj. Equations 4a, 4b and 12-17 describe the lay-up consolidation process during the lamination of N prepreg layers. [Pg.506]

Figure 5 The h-t relationship for the lamination of five prepreg layers. Figure 5 The h-t relationship for the lamination of five prepreg layers.
Cut and stack prepreg layers and laminate 8 ply composites in a 0/90 symmetrical lay-up using a 150°C final cure. [Pg.351]

Most unidirectional composites are manufactured from prepreged layers of yarns. Each layer is called a lamina and a group of lamina is called a laminate. Each lamina in the laminate can have a specific direction based on the design requirements starting from an arbitrary direction. The only important matter to remember is that these laminates must have a mirror symmetry around their neutral axis otherwise they will warp immediately after manufacture and cannot be straightened. This happens due to the difference in the thermal expansion coefficients between the fibers and the matrix and between different lamina causing one side to permanently expand more than... [Pg.359]

Multilayer lamination processing is important to ensure good resin flow and full wetting of resin to glass in the prepreg layers. Vacuum, temperature, and pressure profiles are all important. [Pg.197]

Structure. Figure 23.21 shows the structure and cross-sections for an ALIVH product. The PCB consists of laser-produced blind vias. The core material is an epoxy-aramid laminate. The man-made aramid filaments are ideal to be cut with a CO2 or UV laser. If the DuPont Kevlar filaments are added, then the resulting material wiU have a very low coefficient of thermal expansion (CTE).This is useful for mounting ceramic packages and for direct attachment of flip-chip integrated circuits. The structure can be as simple as a two-sided PCB or as complex as a many-layered PCB. The vias consist of a copper-epoxy paste that connects the top and bottom copper foil. If used as a prepreg layer without copper, the vias connect the various ALIVH layer pairs into a multilayer structure. This is not a sequential build-up process, but rather a parallel build-up process. [Pg.522]

In all cases, the substrates are prepared by the careful orientation of the individual prepreg layers (to obtain the properties required) which, after being cured under pressure at temperatures between 120 and 175°C, form the composite laminates that become the adherends in the structure. [Pg.245]

One of the most often used production procedures for fabricating a high-performance structural laminate is the Autoclave/Vacuum Degassing (AC/VD) laminating process. In this process, individual prepreg plies are laid up in a prescribed orientation to form a laminate. The laminate is laid against a smooth tool surface and covered with successive layers of glass bleeder fabric, Mylar or Teflon sheets, and finally a vacuum... [Pg.102]

All specimens were made from IM7/977-2 prepreg supplied by Cytec. One single panel, 300 mm X 750 mm was laid up by hand on a warm table because the prepreg was not particularly tacky. Hot de-bulks (vacuum only, 60 C) were carried out after every fourth layer. A 10 p.m FIFE film was inserted in the mid-plane of the laminate in order to simulate an artificial crack. A final pressurised de-bulk (120 C, 3 bar pressure, 30 minutes) was carried out in order to reach a laminate thickness close to neat cured thickness, prior to Z-pinning with 0.28 mm diameter pins (T600/BMI), at densities of 0.5%, 2% and 4% in the selected locations. Table 1 summarises the range of specimens made. [Pg.505]

As can be seen in Figures I and II, the processing involves impregnating the fiberglass with the uncured epoxy resin solution, and finally fully curing layers of the prepreg with copper foil into a finished laminate. From this point the laminate is fabricated into a finished printed circuit board. [Pg.78]


See other pages where Prepreg layer lamination is mentioned: [Pg.20]    [Pg.499]    [Pg.501]    [Pg.501]    [Pg.503]    [Pg.507]    [Pg.507]    [Pg.508]    [Pg.509]    [Pg.2317]    [Pg.299]    [Pg.125]    [Pg.414]    [Pg.2765]    [Pg.8535]    [Pg.124]    [Pg.349]    [Pg.183]    [Pg.124]    [Pg.429]    [Pg.20]    [Pg.42]    [Pg.2320]    [Pg.3032]    [Pg.80]    [Pg.25]    [Pg.83]    [Pg.124]    [Pg.206]    [Pg.331]    [Pg.372]    [Pg.469]    [Pg.220]    [Pg.383]   


SEARCH



Laminated layer

Prepreg

Prepreg layer lamination single

Prepregs

© 2024 chempedia.info