Vacuum press

Hoyt and Chorne [230] have recently reported the preparation of several self-bonded dense borides. EuBe (90%) was made by hot vacuum pressing in graphite dies at 1800—2000° C. Temperature, pressure and time are important variables. Unsuccessful attempts have been made to prepare EUB4. 

Materials. Commercial polypropylene and poly(4-methylpent-l-ene) powders containing no commercial additives were supplied by I.C.I. (Plastics Division) Ltd. The powders were vacuum pressed into film of 200-/x thickness at 190° and 280°C respectively, for 1 min. The n-hexane was of spectroscopic quality. 

VCEMA vinyl chloride-ethylene-methyl acrylate VPM vacuum-press molding... 

Produce copper-LCP 2. Vacuum press for adhesiveless copper bond... 

Faustel, Steinemann, Gasway, all from USA, also Homag Germany for vacuum press machines which are used for PVC film lamination in woodworking. 

Fig. 6 shows an interesting application of wood adhesive 3D boards may be finished with PVC laminated foils by vacuum pressing. The figure shows the three steps of manufacturing. Doors of kitchen cabinets and home doors are now often made by using this technique. 

Figure 6 3D laminating of PVC film onto 3D panels (made of MDF). This is a heat laminating on a vacuum press (courtesy of Biirkle Germany). 

Vacuum-Assisted Hydraulic Lamination. Many hydraulic presses use a vacuum to eliminate volatiles. Users of vacuum presses report a reduction of edge voiding and the ability... 

The standard hydraulic vacuum press cycle is flexible and has very high output. Through the use of multiple openings and stacked lamination, high productivity is obtainable. Hydrauhc lamination works effectively with all modern materials systems. 

It takes more than one and a half hours for the whole heat press cycle to complete the chemical curing reaction of the adhesive resins, therefore the batch size and the lamination equipment have been becoming larger to make the productivity higher. But it makes the process flexibility lower. A quick press system has been developed to have a better flexibiUty. One set of coverlay films and an etched flexible circuit panel is hold in a small vacuum press for less than two minutes as the preliminary lamination. After that, several numbers of panels are baked in a thermal oven to complete the chemical curing of the adhesive resin. This process needs a special epoxy resin for the adhesives, but it provides a high flexibility for the small volume and prototype productions. 

Appropriate dummy boards are prepared for the flexible part during the bonding process. A vacuum press is preferred for good bonding quality. An autoclave system is recommended for complicated circuit constructions, because the autoclave can create uniform pressure on the entire circuit. Suitable baking should be done prior to lamination or bonding processes. 

Uni-directionally reinforced strands are the essential components in the manufacture of woven composites. In similar maimer, the uni-directional reinforced plies are the basic building blocks of laminates. The latter contain a lay-up of several, multi-oriented plies and are formed by the appUcation of a prescribed regime of pressure and temperature within an autoclave or a vacuum press. 

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