DE3114401A1 - Calibrating devices for plastics profiles - Google Patents

Abstract

The invention relates to calibrating devices for plastics profiles. In the production of plastics profiles, calibrating devices undertake the final shaping of a desired profile. They may comprise rigid deflectors, plates, boxes or the like, past which a strand of plastic is passed to produce a plastics profile. As this happens, relatively great frictional forces occur between the strand of plastic and the calibrating devices shaping the profile, which has adverse effects on the plastic. The invention provides for calibrating devices which run along with the strand of plastic to be used, said devices being able to take the form of running belts, crawlers or the like and being designed according to a respectively desired plastics profile shape. Using this type of calibrating device, frictional resistances between the faces of the plastics profile and of the moving calibrating devices are reduced, as a result of which there is minimal stressing of the surface of the plastics profile and thus its physical properties are retained.

Description

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Patent application

Ing. (Grad) Manfred Riedel, Klein-Roscharden, 4595 Lastrup (Oldbg)

Calibrators for plastic profiles

Plastics are used in the manufacture of hollow and solid profiles preferably melted in an extruder, pressed through a nozzle similar to the profile, the tool, and then withdrawn while cooling, so-called calibrators take over the final shape of the plastic profiles. These calibrators consist of possibly adjustable, but relative to the pulling direction of the plastic strand rigid panels, panels or boxes. The large areas of contact between the moving plastic strand and the rigid calibrators cause considerable frictional forces, which not only adversely affect the plastic can affect (permanent elongation, relatively high longitudinal shrinkage, i.e. reduced dimensional accuracy, deterioration surface properties), but also large ones Require trigger devices.

Since the said frictional forces are also a function of the take-off speed are the plastic profile calibrators current conception to determine the production speed Factor in such a way that the extruder

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capacity is only partially used.

The invention hereby registered consists in a new \ calibrator conception, which not only leads to improvement: the? Plastic profile quality, but also too serious. iro-i can lead to increased ductility. The main feature of these ^: new calibrators is that their contact surfaces with the plastic strand move in the same seal as this one, thereby drastically reducing the frictional resistances. ]. To achieve a certain plastic profile shape, the treadmills, sai, etc. can be smooth, profiled; divided lengthways and transversely, combined with one another and with rigid contact surfaces of the same and different heights and widths, flat, concave, convex and angled. Compliance with \ certain;. bmessurif.ex: <iei plastic profiles are made by · mechanical, pneumatic, hydraulic etc. reached, whereby the supporting media (zh retail plates, air, .'asser, ceI, etc.) can sometimes serve as a cooling agent for the application of the, vL-arms made of the: neiiien plastic.

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The contact of the plastic strand surfaces with the calibrator surfaces can be caused by increased internal pressure in the plastic profile, by applying a negative pressure from the outside or by a Combination of both methods can be effected.

The calibrator treadmills, caterpillars, etc. can either be active, e.g. by motors, driven or carried along by the plastic strand moved by the pull-off devices will; a combination of these two types of drive is also possible. This allows the currently necessarily large-sized trigger devices are omitted or be reduced. The reduction of the frictional resistance between plastic profile and moving calibrator surfaces allows the minimization of undesired, molecular longitudinal orientations, frozen tensions and longitudinal shrinkage, thus an improved dimensional accuracy of the finished plastic profiles, as well as only minimal stress the plastic profile surfaces, making their physical and aesthetic properties are optimally preserved.

The by the new calibrator conception according to this He-making possible increase in production speed is not only an economic advantage, but leads also to a shortening of the residence time of the plastic in the extruder, whereby the thermal degradation is reduced which is directly related to improved properties of the art

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fabric profile is connected.

The accompanying drawings 1 to 4 show examples of the design of the calibrators for plastic profiles according to of this invention. For the sake of clarity, there are devices for adjustment, pressure application and cooling omitted.

Claims (4)

3_. Claims | .1 .. calibrators in the form of individual or combined, movable, actively or passively driven treadmills, caterpillars, etc .; 1. 2. Combinations of moving treadmills, caterpillars, etc. with rigid calibrator surfaces; 3. Profiling of the calibrator treadmills, caterpillars, etc. through segmentation, convex, concave and angled shaping; 4. Plastic profiles that comply with the claims $ .1. until i.J. named calibrators were manufactured.