Continuous compression molding

The continuous compression molding (CCM) machine (see Fig. 8.18) works on the basis of a semi-continuous process. It was first industrialized for the production of FRTP material by Advanced Composites and Machines GmbH, Friedrichshafen, Germany (today ). The production of profiles using the CCM technology was filed for patent in 1991.  

There is a big variety in reinforcement material that can be used in the CCM process, because there are no special requirements as to the material. 

Like the pultrusion process, the selection of a suitable thermoplastic matrix material mainly depends on the desired mechanical properties and the desired long-term service temperature. The range of usable matrix materials starts with standard polymers such as polyethylene (PE) or polypropylene (PP) and ends with high performance polymers such as polyetherimide (PEI) or poyletheretherketone (PEEK). Recent developments have shown that the processing of reactive thermoplastic materials is possible as well (CBT). For some physical properties of common matrix materials see Table 8.2. ° 

For the in situ production of panels or profiles designed as sandwich structures, there are only some core materials that can be used because of the high temperatures during the process. PMMA foam (product name  

19 Schematic of a powder-prepreg unit (IVW GmbH). (From reference 37.) 

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Figure 14.5. Equipment for continuous compression molding of polyethylene material. [Adapted from Kobayashi K, Mizoe T, Iwanami Y, Yokoyama S, Jimbo K, Kurihara K, Yazawa H, Okada M, US Patent 5,106,558, 1992.]...

The Prolong process is similar to the previously described DURASUL except that an electron beam irradiation dose of 65 kGy is used for Prolong and continuous compression-molded bars are processed as with Longevity. Components are machined from processed Prolong maferial, enclosed in gas-permeable packaging, and sterilized by gas plasma (Figure 15.6). 

The following section will give a detailed description of a continuous compression molding process using a pressing unit which is equipped with one continuous tool. 

Preferred application areas for the pultnision process and continuous compression molding process... 

Figure 1.23. Continuous compression molding [image courtesy of the Institut fUr Verbundwerkstoffe GmbH, Germany]...

PTFE grains can also be processed by extrusion of the powders followed by compression. This technique corresponds to a continuous compression molding. 

Sheet molding compound (SMC) consists of randomly oriented chopped fibers in a matrix of resin and filler. SMC is produced in the continuous manner shown in Figure 1-16. Note that the polyethylene film protects the roller system from getting gummed up with the resin-filler paste. The rug-like rolls of SMC are then used in compression molding machines to create large parts such as the sides of cars and trucks. 

Figure 19 illustrates one type of compression mold suitable for molding lip type shaft seals with a metal outside diameter (O.D.). Figure 19a shows the compound preform resting on the shelf and the mold beginning to close. The mold continues to close until it gets to the position shown in Fig. 19b. Finally, the mold opens as shown in Fig. 19c. It can be seen that this molding technique produces a molded lip seal with the flash already removed. In general, when using a vacuum chamber on the press, to ensure that all the air and/or gases are evacuated from the mold after closure, one or...

Phenolic resins Good acid resistance, good electrical properties (except arc resistance), high heat resistance Compression molding, continuous lamination... 

Compression molding Filament winding Hand lay-up Mat molding Pressure bag molding Continuous pultrusion Injection molding Spray-up... 

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