Profile geometry

Fig. 42 shows this relationship for such a liquid (lubricant for steam engines with ca. 7 % A1 stearate, t, = 9.7 Pa s, = 0.205 s-1). This was established with two differently sized (d = 60 and 90 mm) single-screw machines with the same profile geometry using two rotational speeds (n= 1.65 and 25 min 1). Independent of the screw diameter, the curves coincide for nY = const. The higher the rotational speed, the higher is the shear stress the straight line (a), which is also valid for Newtonian liquids, adjusts as the limit case (p= x ). 

Figure 7.7 shows a typical rubber profile extrusion line. Several days prior to the extrusion itself, the raw rubber is prepared in an internal mixer, where certain materials such as sulfur or carbon black are added to achieve the required properties. One or more extruders form the head of the production line. There, the rubber is kneaded, heated, intermixed, and then extruded through specially formed dies (final delivery elements) which are responsible for attaining the required profile geometry. A major part of the line is taken by the vulcanization process, usually achieved by near infra red and microwave heating. After optical quality control, the profile is cooled down and cut into pieces of a certain length. 

Profile evolution techniques measitre only diffusion driven by chemical gradients (as opposed to tracer diffusion) for heterodiffirsion, but in suitable profile geometries can do so very directly with a minimitm of complicated modeling. The utility of a given method is hmited by (a) the variety of adsorbates it can monitor without major siuface perturbation, (b) the spatial resolution it can attain (including initial profile formation), and (c) the suitability of the initial profile geometry for qrrantitative analysis. 

The pulling force is proportional to the circumference of the composites contacting the die, that is, the bigger and the more complex the profile geometry, the lower the maximum rate of production due to increasing pulling forces. 2... 

The CCM process enables the production of profiles with various geometries. It is possible to produce open profiles as well as closed profiles with a hollowed core in a single step process. Figure 8.28 gives an overview of possible profile geometries. The freedom in profile design is mainly limited... 

J is applied. A crash test sequence is shown in Fig. 8.33. The profile is bent up to the maximum deformation of about 107 mm. Subsequently the test sled was pushed backwards by the restoring force of the profile due to the elastic strain of the profile. This sequence clearly demonstrates the integrity of the profile and especially of the in situ joined zone, which is definitely not the weak point of the chosen profile geometry and material under the given load conditions. 

The rate of production subsumes the relevant process parameters (e.g., temperature, pressure, length of the respective tools, or the pulling resistance). Furthermore, the specific rate of production P is shown in Fig. It is defined in terms of the profile geometry, in... 

To meter the applied film, a profiled (or grooved) rod is usually used. Different profile geometries allow for different film thicknesses. Therefore, variation of the size concentration for pick-up control is no longer needed. With a given rod profile, an additional but limited variation of the size pick-up is possible by adjusting the rod pressure. 

SCALE UP RULES FOR PROFILE GEOMETRIES IN EXTRUSION DIES AND OPTIONS TO ADJUST SURROUNDING FLOW CHANNELS TO AVOID... 

If, in addition to the width, height or diameter of the profile geometries, the flow length or the consistency factor is varied too, this can be taken into account by means of Equations 22 and 23. 

Using the model laws and scale-up rules shown here, it is possible to design profile geometries in a simple, rapid and hence low-cost manner on the basis of a die that already exists. 

Fig. 8 Iterative solution to calculate Li and L2 Key Words Extrusion dies, profile geometries, transverse flow...

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