Caul plate

Collation. Collation is the process by which the individual laminate pHes are assembled prior to curing in the press. The buildup of the laminate determines the final properties of the product. The topmost sheet in the buildup may be a texturing or embossing paper as well as being a release sheet to allow for separation of the laminate from the caul plate used to mold it. 

Waferboard, a more recent wood constmction product, competes more with plywood than particle board. Waferboard and strand board are bonded with soHd, rather than Hquid, phenoHc resins. Both pulverized and spray-dried, rapid-curing resins have been successfully appHed. Wafers are dried, dusted with powdered resin and wax, and formed on a caul plate. A top caul plate is added and the wafers are bonded in a press at ca 180°C for 5—10 min. Physical properties such as flexural strength, modulus, and internal bond are similar to those of a plywood of equivalent thickness. 

As illustrated in Figure 10.2, many composite applications utilize a caul plate or pressure intensifier. Caul plates result in a greatly improved part surface finish compared with a bag surface, improved dimensional control, and improved radius quality. Caul plates are also used to reduce ply movement during processing of honeycomb reinforced parts. Caul plates may be semi-rigid or rigid in nature. Semi-rigid caul plates, which are the most common type, are typically constructed of thin metal, composite, or rubber materials so they are flexible in... 

Rigid caul plates are typically constructed of thick metal or composite materials. Thick caul plates are used on very complex part applications or cocured parts where dimensional control is critical. Many rigid caul plates result in a matched die configuration similar to compression or resin transfer molding. Parts processed in this manner are extremely challenging because resin pressure is much more dependant on tool accuracy and the difference in thermal expansion between the tool and the part. Tool accuracy is critical to ensure no pinch points are encountered that would inhibit a tool from forming to the net shape of the part. 

The texturing sheet may also contain a plastic coating that transfers to the laminate surface during the laminating process to provide special surface properties. The caul plate itself may be smooth or textured and act directly as the release. Immediately beneath this release sheet, there may be a decorative layer or a ply that imparts special properties such as a metallic foil for electrical conductivity or a static dissipating layer. If the decorative layer is a printed... 

Non-porous Teflon Caul plate Non porous Teflon... 

After the fibre mat is formed, it is typically prepressed in a band press. The densified mat is then trimmed by disc cutters and transferred to caul plates for the pressing operation. Dry-formed boards are pressed in multi-opening presses with temperatures of around... 

There are other variations of the RTM, VARTM and CRTM process which belong to the class of LCM processes such as RTM light in which a caul plate is introduced on top of the bag, resin infusion under flexible tooling (RIFT), resin film infusion (RFI) and vacuum injection preform relaxation (VIPR). In addition many of the same processes are known by different acronyms. It is useful to note that as the science base of RTM improved and led to better understanding of the variables and parameters that influence the flow and dry spot creation in RTM, it led to approaches and creative ideas to improve the process and cut down the cost. This learning continues today to evolve new modifications to the LCM family of processes. For example in VIPR one can now introduce flow control effectively to modify the flow front and create a part that is better than the SCRIMP process and is of consistent quality. ... 

Additional tooling pieees For improving the part s geometrical accuracy, it is possible to use additional pressure pieces (in comers) or caul plates (on larger surfaces). Hollow structures would necessitate moulding cores, e g. inflatable or in some other way removable ones. 

Vacuum set-up Configuration and sequence of ancillary materials configuration and sequence of caul plates, cores, pressure pieces leak test conditions (differential pressure, pass/no pass criteria)... 

Tooling Plates. The outermost item in the stack is termed a caul plate or carrier plate. These are thick, oversized metal plates, generally made of % in. (9.525 mm/0.375 in.) thick steel.The 4130 alloy of steel is often chosen due to its precision machining capabiUty for placement of the holing holes. Sometimes a hardened aluminum alloy is chosen, but is not highly recommended due to its high in-plane expansion. The purpose of the caul plate is to provide a stable base to transport the ML-PWB stack. 

Heated platen (also cooling) Caul plate... 

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