DE102016125115B4 - Device and method for producing circular or segmental geometries of thermoplastic plastic multi-chamber hollow profiles - Google Patents

Abstract

Device for producing circular or circular segment-shaped geometries of thermoplastic malleable plastic multi-chamber hollow profiles, consisting of a heat source for applying thermal energy to the surface of the plastic multi-chamber hollow profile to be treated, the heat source being surrounded by a heating chamber, the heating chamber as an elongated, box-shaped structure (2) which is closed on three sides and has two opposite side walls (3) and a base (4), the plastic multi-chamber hollow profiles to be deformed being accommodated in the interior space (R) which is open at the top, characterized in that that on the inside of the side walls (3) and the bottom (4) in the longitudinal direction of the structure extending, elongated and paired infrared emitters (9) are arranged, the infrared emitters (9) towards the interior (R) of the structure with a flat cover that is permeable to infrared radiation (5) are provided, and partition plates (6) which are arranged to be displaceable in the longitudinal direction of the structure and are impermeable to infrared radiation and which cover the infrared radiators (9) in the direction of the interior on the side and / or on the floor side in order to heat up zones of varying degrees of heating of the plastic to be deformed. To create a multi-chamber hollow profile.

Description

The invention relates to a device and a method for producing circular or circular segment-shaped geometries of thermoplastically deformable plastic multi-chamber hollow profiles, consisting of a heat source for applying thermal energy to the surface of the plastic multi-chamber hollow profile to be treated, the heat source being from a Heating room is surrounded according to the preamble of claim 1 and on the process side with a teaching according to claim 12.

The known prior art in the production of circular or circular segment-shaped geometries of thermoplastically deformable plastic multi-chamber hollow profiles, for example for use in the production of window or door frames or frames, consists in heating the profile in question in a necessary manner Immerse the glycerin bath and provide the necessary thermal energy in this regard. Typical glycerine bath or oil bath temperatures are around 130 ° C.

If hot air drying ovens are used to heat a hollow plastic profile, a rather long dwell time in the oven has to be accepted, whereby a large part of the thermal energy has already been released into the environment after the part to be bent has been removed.

A decisive disadvantage of the use of glycerin-containing liquid or hot air as a medium for contact heating of the multi-chamber hollow profile systems is the heating or heating of the profiles by flowing oil or glycerol-containing liquid or hot air around the outer contours and thus only indirect heating of the material without a possible influence on a targeted, selective and therefore differentiated supply of thermal energy directly from the heat source into or on the material. In addition, after immersing the hollow profile in an oil or glycerol-containing bath, appropriate cleaning of the profile is to be ensured, which is often difficult or possible with great effort in the case of hollow profiles through trained chambers or undercuts.

In wet bending, the bath has to be filled up cost-intensively due to the technologically-related consumption such as evaporation, dripping, washing off the bent parts and the like. After the end of work, the bath temperature drops considerably until the next day, so that the bath has to be heated again in an energy-intensive manner.

From the AT 512 718 B1 is a method and an apparatus for bending a corner in a profile made of thermoplastic base material. It is a basic material for the production of plastic spacer frames for insulating glass windows. According to the teaching there, local heating by means of a heating device up to a softening point is to be realized in order to avoid bulges in the bending area, in particular when a polygonal body has to be bent, the total width of the bent corner between two in the bending zone of the bending device Calibration surfaces of a calibration device is limited to a target dimension, in particular to the initial width of the bent profile. In relation to the heating, the inside and the outside of the profile are heated by the heating device to different softening temperatures.

With the heater according to AT 512 718 B1 the heating time can be preselected differently via the heating output on the inside and outside of the profile.

The heating device can comprise at least one infrared radiation element.

For the production of polygonal spacer frames with three or more corner areas, made from an elastically-plastically deformable plastic material is according to DE 20 2015 105 146 U1 a heating device is provided which is used to heat the corresponding profile or parts thereof to a predetermined temperature close to the melting point of the material of the profile.

With regard to the heating processes or heating devices used there, reference is made to induction, resistance, ultrasound, infrared or high-frequency systems. In the case of induction or resistance heating, heating elements are embedded in the respective plastic profile. Accordingly, the heating effect is achieved directly in or on the material of the profile and the heat is transferred directly to the plastic of the profile. The heating elements can extend sectorally, that is to say in sections, over the length of the profile, or else can be embedded throughout the profile. By using pyrometers and by using a control circuit, temperature profiles can be simulated and controlled, depending on the choice of the plastic used for the production of the profile and other sizes.

From the foregoing, it is an object of the invention to provide a further developed method and an associated device for producing circular or circular segment-shaped geometries of thermoplastic deformable plastic multi-chamber hollow profiles, which makes it possible in an effective, energy-saving manner completely to process differently designed hollow profiles, especially for window and / or door construction. The disadvantages of the previous heating in a liquid bath with the consequent necessary cleaning steps of the profile are to be eliminated, as is the likewise energy-intensive heating by means of hot air, which also leads to the environment being unnecessarily subject to extreme heating, which results in poorer working conditions.

The object of the invention is achieved with a device according to the combination of features according to patent claim 1 and with a method according to the teaching according to patent claim 12.

It has surprisingly been found that the device according to the invention with a heating space as an elongated, box-shaped structure closed on three sides enables rapid, adequate and targeted heating through to the softening and bending temperature of completely different hollow chamber profiles, while simultaneously monitoring the Surface temperature of the profile to be deformed can be avoided.

Due to the partition plates used according to the invention, which are displaceable in relation to the longitudinal extent of the structure and the receiving space, depending on the desired circular segment or arch shape, a setting of colder, non-deformable sections can be selected, so that in a single bending process after heating the complete profile several, also different bending zones can be realized, between which straight sections extend.

Depending on the dimensions of the free interior of the structure and the sizes of the profiles to be deformed, several profiles can be heated simultaneously and subjected to the desired bending step one after the other. The arrangement of the infrared emitters ensures that, despite the open top of the structure, which is advantageous for handling, uniform heating of the hollow profiles is ensured.

Flat and flat covers which are permeable to IR radiation, in particular with regard to the base and parts of the side walls of the structure, enable the hollow profile to be placed over a large area and at the same time ensure that the infrared radiation is homogenized, so that hot spots cannot occur. In contrast to grid-like or net-like contact surfaces for the hollow chamber profiles, there is also no risk of the profiles being damaged on the surface.

In the embodiments of the invention, pyrometers used can be pivoted in order to be able to point the same to the respective profile for detecting the surface temperature.

There is also the possibility of designing at least some of the infrared emitters, which are preferably arranged in pairs, in an adjustable manner, in particular in a height-adjustable manner.

The device according to the invention thus comprises a heating space in the form of an elongated, box-shaped structure closed on three sides.

This structure has two opposite side walls and a bottom.

On the inside of the side walls and the bottom, elongated and paired infrared radiators are arranged in the longitudinal direction of the structure.

The infrared radiators are provided in the direction of the interior of the structure with a flat cover which is permeable to infrared radiation, the remaining interior which is open at the top serving to temporarily accommodate the plastic multi-chamber hollow profiles to be deformed.

The radiation-permeable cover is preferably made of a quartz glass or borosilicate glass.

In the longitudinal direction of the structure, the already mentioned bulkhead plates, which are opaque to infrared radiation, are arranged displaceably. The bulkhead plates cover the infrared radiators towards the interior on the side and / or bottom, in order to create the desired zones of varying degrees of heating of the plastic multi-chamber hollow profile to be deformed.

The heating chamber is preferably double-walled, with fans being provided at least on the bottom for cooling and for avoiding local overheating. The double wall also ensures that the outside surface temperature of the device does not exceed a maximum temperature in order not to endanger the worker or operator.

The aforementioned cover made of glass, in particular quartz glass or borosilicate glass, is floating so as to avoid thermally induced stresses.

At least the infrared radiators formed on the side walls are rod-shaped and adjustable, in particular height-adjustable.

The surface of the side walls and / or the bottom is designed to be reflective for infrared radiation in order to increase the thermal efficiency of the device.

In a preferred embodiment, the structure has an essentially U-shape, the connecting leg being implemented as the bottom.

The end faces of the structure are designed to be open for the introduction of longer hollow profiles or to be open at least on one side.

As mentioned, the structure has one or more pyrometers for detecting the surface temperature of the hollow profile introduced. The pyrometer or pyrometers are connected to a control unit in order to specify the electrical energy supplied to the infrared radiators, with the result of an increase in efficiency when operating the device and at the same time avoiding inadmissibly high surface temperatures of the plastic materials to be deformed.

A radiation-homogenizing distance is provided between the cover and the infrared radiators.

In the area of the interior open at the top, at least one additional pair of elongated infrared emitters is located in front of the opposite side walls, the main radiation direction of which is oriented toward the interior, in particular towards the center of the interior, and thus at an appropriate angle.

In the method according to the invention for producing circular or circular segment-shaped geometries of thermoplastically deformable plastic multi-chamber hollow profiles, the hollow profile workpiece to be deformed is first introduced into the interior of the structure. With certain hollow profiles, it has proven to be advantageous to insert, in particular to insert, filling tools that are matched to the profile into sections of the hollow profile. These filling tools preferably consist of an elastic, bendable material which is not influenced by the temperature effect, which fills the cavity and follows the bending process due to its elasticity. This prevents undesired buckling of sections of the hollow profile due to compression processes.

After the hollow profile has been introduced into the interior, the partition plates are then adjusted by shifting with regard to the desired heating zone or with regard to the necessary colder sections.

The infrared emitters are then activated after selecting the maximum surface temperature based on the hollow profile used. The result is an immediate, direct heating of the hollow profile with independent regulation of the infrared radiators when the surface temperature is reached. After the heated hollow profile has been removed, it can be subjected to the bending process using a bending tool with the aid of a suitable bending shape.

The invention will be explained in more detail below using an exemplary embodiment and with the aid of a figure.

The figure shows a cross section of the device according to the invention with a receiving space, which starts from a structure with an essentially U-shape, the connecting leg of the U forms the bottom of the device and the workpiece to be deformed, namely a plastic multi-chamber hollow profile, can be introduced via the open upper side or openable end faces.

The device according to the basic illustration according to the figure of the exemplary embodiment is based on a frame 1 which spans several feet. The device further comprises a module housing 2 ,

The module housing 2 is designed as a heating room in the form of an elongated, box-shaped structure closed on three sides.

This structure comprises two opposite side walls 3 as well as a floor 4 ,

Inside the side walls 3 are elongated and paired infrared emitters E3 and E4 such as E5 and E6 located.

In the floor area there are further paired infrared emitters E8 and E7 ,

The infrared emitter E3 . E4 . E5 . E6 and E8 and E7 are towards the interior R of the structure with a flat cover that is permeable to infrared radiation 5 , preferably made of glass.

The remaining interior, open on the top R serves to accommodate the plastic multi-chamber hollow profile to be deformed (not shown).

In the longitudinal direction of the structure there are displaceable bulkhead plates which are impermeable to infrared radiation 6 educated.

The bulkheads 6 are in a slide rail arrangement 7 guided and displaceable longitudinally (arrow representations).

Appropriate operating handles 8th enable the aforementioned longitudinal displacement of the bulkhead plates 6 ,

The bulkheads 6 can not only in front of the side infrared emitters 9 , but also the infrared emitters on the bottom E7 and E8 extend overlapping, adjustable.

The module housing 2 is double-walled, with fans at least on the bottom 10 are provided for cooling and to avoid local overheating.

The infrared emitters on the side walls E4 and E6 respectively. E3 and E5 can be made height-adjustable, as symbolized by the further arrow display.

The surface of the side walls 3 and / or the floor 4 can be designed to be reflective for infrared radiation.

As can be seen, the structure shown comprises the side walls 3 and the floor 4 a substantially U-shape, the connecting leg of the U as floor 4 is executed.

In addition, there is the possibility that pyrometer 11 are provided to the surface temperature of the interior R to determine the inserted hollow chamber profile and the infrared emitter via a suitable control unit 9 head for.

Thermal fenders 12 on the module housing 2 serve as protection against accidental contact and to increase occupational safety.

In the area of the interior open at the top R are in front of the opposite side walls 3 at least one pair of additional elongated IR emitters E2 and E1 arranged, the main radiation direction to the center of the interior R is oriented. By combining the arrangement of the infrared emitters E1 to E8 uniform heating of the hollow profile introduced is ensured.

The exemplary dimensions in the illustration according to the figure show the possible sizes of the interior available R and reveal that profiles with customary cross-sectional dimensions for window and door construction can be heated with the device according to the invention and then subjected to the necessary bending process.

With the help of the bulkhead plates which can be moved in the longitudinal direction of the device 6 , each of which only extends over a partial longitudinal section, a targeted thermal partitioning of the elongated plastic multi-chamber hollow profile can be carried out and the areas which are to be acted upon with infrared energy and thermally heated in this regard can be precisely delimited. In a realized embodiment of the device according to the invention, the heated length is approximately 2 m. The exemplary angle of the infrared emitter E1 and E2 based on the center of the interior R is essentially 135 °.

The respective position of the partition plates in relation to the longitudinal extent of the device can be fixed by means of a clamping device and secured against undesired displacement.

Claims (12)

Device for producing circular or circular segment-shaped geometries of thermoplastic malleable plastic multi-chamber hollow profiles, consisting of a heat source for applying thermal energy to the surface of the plastic multi-chamber hollow profile to be treated, the heat source being surrounded by a heating chamber, the heating chamber as an elongated, box-shaped structure (2) which is closed on three sides and has two opposite side walls (3) and a base (4), the plastic multi-chamber hollow profiles to be deformed being accommodated in the interior space (R) which is open at the top, characterized in that that on the inside of the side walls (3) and the bottom (4) in the longitudinal direction of the structure extending, elongated and paired infrared emitters (9) are arranged, the infrared emitters (9) towards the interior (R) of the structure with a flat cover that is permeable to infrared radiation (5) are provided, and partition plates (6) which are arranged to be displaceable in the longitudinal direction of the structure and are impermeable to infrared radiation and which cover the infrared radiators (9) in the direction of the interior on the side and / or on the floor side in order to heat up zones of varying degrees of heating of the plastic material to be deformed. To create a multi-chamber hollow profile. Device after Claim 1 , characterized in that the heating space is double-walled, with fans (10) being provided at least on the bottom side for cooling and for avoiding local overheating. Device after Claim 1 or 2 , characterized in that the cover (5) made of glass, in particular quartz glass or borosilicate glass exists, which is floating to avoid thermal stresses. Device according to one of the preceding claims, characterized in that at least the infrared radiators (E3; E4; E5; E6) formed on the side walls (3) are designed to be height-adjustable. Device according to one of the preceding claims, characterized in that the surface of the side walls (3) and / or the bottom (4) is designed to be reflective for infrared radiation. Device according to one of the preceding claims, characterized in that the structure has a U-shape in cross section, the connecting leg being designed as a base (4). Device after Claim 6 , characterized in that the end faces of the structure for the introduction of longer hollow profiles are designed to be open or at least open on one side. Device according to one of the preceding claims, characterized in that the structure comprises pyrometers (11) for detecting the surface temperature of the hollow profile introduced. Device after Claim 8 , characterized in that the pyrometers (11) are connected to a control unit in order to specify the energy supplied to the infrared radiators (9). Device according to one of the preceding claims, characterized in that a radiation-homogenizing distance is set between the cover (5) and the IR radiators (9). Device according to one of the preceding claims, characterized in that at least one additional pair of elongated infrared emitters (E1; E2) is arranged in the area of the interior space (R) which is open at the top in front of the opposite side walls, the main radiation direction of which is towards the center of the interior space (R) is oriented. Method for producing circular or circular segment-shaped geometries of thermoplastic mouldable plastic multi-chamber hollow profiles, comprising a heat source for applying thermal energy to the surface of the hollow profile to be treated, the heat source being surrounded by a heating space with a device according to one of the Claims 1 - 11 , comprising the following steps: introducing the plastic multi-chamber hollow profile to be deformed into the interior of the structure and inserting filling tools into selected sections of the hollow profile; Adjusting the partition plates with regard to desired colder sections of the plastic multi-chamber hollow profile to be deformed; Activate the infrared emitters after selecting the maximum surface temperature of the respective plastic multi-chamber hollow profile; Immediate, direct heating of the plastic multi-chamber hollow profile with independent regulation of the infrared radiators when the surface temperature is reached; and removing the heated hollow profile and bending by means of a bending tool and / or bending device.

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