METHOD AND DEVICE FOR WELDING PROFILE BARS

Description

[0001] The invention relates to a method and a device for welding a first profile bar made of plastic to a second profile bar made of plastic.

[0002] From US 3,186,891 A a device for welding plastic profiles is known, wherein the plastic profiles are machined in their mitre area with a parting knife before welding.

[0003] DE 10 2016 104 806 A1 discloses a method for joining profile pieces, wherein tolerance compensation on the joining surfaces of the profile pieces is achieved by cutting off profile material using a machining tool.

[0004] GB 2 376 656 A discloses a device and method for welding plastic profiles. The plastic profiles are cut in the miter area by a circular saw prior to plasticizing to create a groove-like, exposed area that serves to receive molten material to form a weld bead. DE 40 18 145 A1 teaches a finishing device for window frames, which includes parting knives for the frame.

[0005] It is known in the art to produce window frames or partial frames of window frames in welding machines, i.e., machines for joining profile bars. These machines utilize the devices and methods described above. The profile bars are made of plastic, preferably thermoplastic, such as PVC. If this plastic is heated sufficiently, it forms a material-tight bond with another, similarly heated piece of plastic. Such bars can therefore be welded together.

[0006] The processes used in these machines include the following steps: Providing the first profile bar and the second profile bar Heating the profile bars at least on their miter surfaces Bringing together the miter surface of the first profile bar with the miter surface of the second profile bar such that the heated areas of the miter surfaces result in a material-locking connection between the first and the second profile bar.

[0007] The device used for this purpose comprises at least one clamping device, in particular movable along at least one spatial direction, for holding or positioning the respective profile bar, and a heating mirror, which is mounted so that it can be moved and positioned at least along one (further) spatial direction and is intended for heating at least the miter surface of the profile bar or bars. The profile bars are positioned at an angle to one another in the device.

[0008] The angle enclosed by the profile bars usually corresponds to the angle of the frame corner to be created. The profile bars can be moved and positioned along their length on the respective clamping devices. Of course, the clamping device can also be locked at the appropriate longitudinal positions with the appropriate force.

[0009] In the production of plastic window frames, there has always been a requirement that the corner area, i.e., the area where the profile bars are welded together, be visually appealing in the final finish. To create a stable connection in the corner area, a positive connection between the materials of the two profile bars must be created over a certain volume. Joining the two profile bars together then leads to the formation of a weld bead, even on the outer, visible surfaces. Therefore, it is known in the art to use separate finishing machines on which the produced window frames are separately reworked in the corner or miter area.

[0010] This approach has the advantage that the plastic chips generated during post-processing (this material is thermoplastic) are not generated near the heated surfaces of the welding machine, where they could potentially hinder the manufacturing process. However, the disadvantage is that a second machine is required, which requires additional investment (in space and machinery) and also slows down the production of such window frames, thus making them more expensive, as the window frames must be clamped a second time in precise position for machining the corner or miter area.

[0011] The invention has set itself the task of improving this state of the art and, in particular, of developing a proposal that, on the one hand, allows a visually appealing design of the corner area of ​​the plastic window frames and, on the other hand, is economically efficient.

[0012] The object is achieved by a method according to claim 1 and a device according to claim 5.

[0013] To achieve this object, the invention is based on a method as described above and proposes machining at least one profile bar, in particular in its miter area, with a parting knife.

[0014] Furthermore, to achieve this object, the invention proposes that a parting knife is provided in the device for machining the mitre area of ​​the profile bar, wherein the parting knife is mounted so as to be movable and positionable at least along one spatial direction.

[0015] The use of a parting knife in a device or method according to the state of the art opens up surprising advantages! By using the parting knife, the miter surface can now be machined, whereby the orientation of the cutting edge of the parting knife can be cleverly selected to achieve the desired machining without having to implement an additional drive or degree of freedom in the machine. It has also surprisingly been found that the parting knife used next to the hot heating surface does not lead to any additional problems, since the preferably single, long chip generated by the parting knife can be safely and reliably kept away from the heating surface by appropriate active or passive removal devices, in particular a removal channel, and thus does not cause any disruption.

[0016] In an advantageous embodiment, the method is carried out in the exact order of the following steps: Providing the first profile bar and the second profile bar. Processing at least one profile bar, in particular in its miter area, with a parting knife. Heating the profile bars at least on their miter surfaces. Bringing together the miter surface of the first profile bar with the miter surface of the second profile bar such that the heated areas of the miter surfaces result in a material-locking connection between the first and the second profile bar.

[0017] In this variant, the parting knife is used before the profile bar is heated, meaning the profile bar is still cold and not plasticized when it is processed by the parting knife. This is particularly advantageous for a precise final shape that is visible externally.

[0018] In an alternative embodiment, the method is carried out in the exact order of the following steps: Providing the first profile bar and the second profile bar Heating the profile bars at least on their miter surfaces Processing at least one profile bar, in particular in its miter area, with a parting knife Bringing together the miter surface of the first profile bar with the miter surface of the second profile bar such that the heated areas of the miter surfaces result in a material-locking connection between the first and the second profile bar.

[0019] In this alternative variant of the invention, the parting knife is used to (post-)process areas of the plastic profile bar that have already been plasticized by the heating mirror. The parting knife can therefore be used to remove excess plasticized material before joining the mitered surface (the final process step), thus reducing the mass of material available for welding and for forming a weld bead.

[0020] According to the invention, the following sequence of process steps is also possible: Providing the first profile bar and the second profile bar (first-time) processing of at least one profile bar, in particular in its miter area, with a parting knife Heating the profile bars at least on their miter surfaces (repeated) processing of at least one profile bar, in particular in its miter area, with a parting knife Bringing together the miter surface of the first profile bar with the miter surface of the second profile bar such that the heated areas of the miter surfaces result in a material-locking connection between the first and the second profile bar.

[0021] In this process, the parting knife is used at least twice: once before heating by the heating mirror and once after heating. Therefore, the same areas do not necessarily have to be machined with the parting knife in these two processing steps; due to the mobility of the parting knife, it is possible that different areas of the miter surface are machined.

[0022] Of course, it is also possible to reheat the miter area or the miter surface after the second or repeated processing with the parting knife. This leads to an optimized design of the joining area, i.e., the material being welded together.

[0023] Furthermore, the proposal advantageously provides that the profile bars are each provided clamped on a clamping device, and at least one clamping device with the clamped profile is moved during processing.

[0024] The invention also encompasses the variant in which the welded profile bars are machined with a parting knife after the mitered surfaces of the two profile bars have been brought together and welded in the welding machine. Cleverly, the clamped position of the two clamping devices is not released for this purpose, i.e., this machining takes place in the same clamping of the profile bars, thus saving time.

[0025] An advantage of the method according to the invention is that it offers several possibilities for achieving the desired result in the sequence of the various steps. Preferred solutions are those in which machining by the parting-off knife only occurs when the respective profile bar is preferably clamped in the clamping device, and this clamping is used again for further machining before or after parting-off without releasing the clamping device.

[0026] Modern machines in which the device or method according to the invention is used are often equipped with CNC axes. These CNC axes allow elements to be precisely positioned along a longitudinal extension (axis), in a surface or in space, but also to be precisely moved within the respective geometry. It is therefore planned to equip both the clamping device that holds the profile bar (either just one clamping device or both clamping devices, thus both profile bars are also moved) with at least one corresponding CNC axis, as well as the holder of the cutting knife and, if necessary, also the heating mirror. As a result, complex machining curves for the parting knife can then be realized in the surface or in space. This design significantly increases the flexibility of the proposal.

[0027] In a preferred embodiment of the proposal, the processing of the profile bar by the parting-off knife takes place in one or more steps. The proposal is very flexible in the design of the use of the parting-off knife. For example, it is possible to use the parting-off knife in just one step, i.e. in a long, drawn-out cut, and thus complete this processing step. For more complex processing operations (e.g., for more complex profile contours to be machined), however, it may be advantageous to divide the processing step into several sub-steps and, for example, to reorient the parting-off knife between these sub-steps (e.g., repositioning or realigning the cutting edge of the parting-off knife by changing its orientation).

[0028] It is clear that these properties of the parting knife, especially combined with the mobility of the clamping device(s) and of course the mobility of the parting knife itself, significantly increase the machining possibilities and also allow the machining of complex contours on the miter surface or in the miter area.

[0029] On the one hand, the proposal provides that (in particular only) the profile edge that defines the outside of the profile, in particular the top and bottom of the profile, the inside rebate or the outside corner, and the mitre surface of the profile bar, is machined by the parting knife.

[0030] However, the use of the parting knife according to the invention is not limited to this; the web walls that separate the profile chambers from each other inside the cross-section can also be machined in the same way with the parting knife. The advantage, especially when machining the profile edge, i.e., on the outside of the profile, is that these represent the visible areas on the outside of the corner joint, and the proposed machining with the parting knife leads to a visible improvement in the resulting frame or sub-frame.

[0031] According to the invention, the parting knife processes the profile bar, particularly in its miter area. The miter area is defined by the fact that a weld to the other profile bar occurs in this area. The miter area therefore comprises the miter surface, i.e. the end surface of the cut, preferably diagonally cut, profile bar and also the respective profile edges, as well as a few millimeters (depending on the degree of heating, this can be 3.7 or even more than 10 millimeters) of the end region of the profile bar in the longitudinal direction of the profile bar. It should be expressly mentioned here that processing by the parting knife is not limited to the miter area, i.e. the device and method proposed according to the invention also expressly covers and includes the use of the parting knife on other areas of the profile bar, remote from the miter area.

[0032] According to the invention, the device is provided with a holder which carries the parting-off knife. It is provided that the holder carries the parting-off knife directly, i.e. immediately, or indirectly, i.e. indirectly, for example via further elements. In an improved embodiment, more than one parting-off knife is provided on the holder. It is therefore advantageously possible for a first parting-off knife to machine the first profile bar and a second parting-off knife to machine the second profile bar at the same time. Such a processing method is not only efficient, i.e. time-saving, but also results in a high level of precision. Cleverly, the two profile bars are each clamped on a clamping device which is at least longitudinally movable and can be positioned precisely along this spatial direction relative to the holder with the parting-off knife thanks to the design of the CNC axes.It has been found that preparing the miter surfaces as precisely as possible, parallel to each other, improves the welding result. Due to this parallel alignment of the miter surfaces, the two parting knives can then perform corresponding machining operations on the first and second profile bars (preferably in the same work step), for example, creating a chamfer on the profile edge, which is then combined into a shadow groove in the welded corner area or otherwise efficiently prevents the formation of a weld bead. A shadow groove is an ideal way to visually compensate for profile tolerances in the miter area.

[0033] Furthermore, the device is provided with the holder also carrying at least one milling cutter, in particular a face milling cutter. The milling cutter, in particular the face milling cutter, allows for additional machining options; in particular, the machining is cleverly divided between these two cutting machining tools (cutting-off knife and milling cutter). Preferably, for example, the cut-off knife is intended for machining the profile edge, i.e., for the visible outer area of ​​the profile, while on the other side the (face) milling cutter preferably machines the cross-sectional area as a whole. Of course, it is also possible for the milling cutter to first machine the surface and then, if necessary by repositioning the holder relative to the profile bar(s), for the cut-off knife to rework the profile edge.By arranging the milling cutter and the parting-off blade on a common mount, the mount's mobility can be utilized for both the parting-off blade and the milling cutter. The mount also accommodates a rotary drive for the milling cutter.

[0034] Although parting-off cutters and milling cutters, especially face milling cutters, are both cutting tools, they are clearly different from each other. A milling cutter is mounted on a rotatable holder, driven by a rotary drive. The holder moves the tool along the machining path. In contrast, the parting-off cutter is rigidly mounted on the holder.

[0035] Milling cutters typically have multiple cutting edges, although so-called single-edge cutters are also known. The cutting edges of milling cutters only temporarily engage the material during machining, along the machining path. In contrast, the parting-off cutter is permanently in contact with the material along its machining path.

[0036] Due to the different uses of the cutting edges of the milling cutter and the parting knife, the chips generated when using the machining tools also vary significantly. The milling cutter produces relatively short chips, whereas the parting knife produces a few, preferably only one, but very long chips.

[0037] The solution according to the invention further provides that before heating the profile bar, in particular the miter surface, is machined by a milling cutter, in particular a face milling cutter. Various procedures are possible. Firstly, machining is carried out by the milling cutter first, followed by machining by the parting-off knife. A reverse sequence is also possible, however, i.e. the parting-off knife processes first, followed by milling. Of course, according to a variant of the invention, these two machining steps can also be carried out simultaneously. In a further variant, the milling cutter is used again after the miter surface has been heated.

[0038] The machining capabilities of a device equipped in this way are significantly increased when the parting-off knife is used in combination with a milling cutter. For example, the milling cutter is used for fast, large-area machining, while the parting-off knife is used for creating a corresponding chamfer on the profile edge. The contour of the parting-off knife can be freely selected and its positioning can also be adjusted as required, thus enabling even complex machining tasks.

[0039] Furthermore, it is advantageously provided that the holder carries at least a first and a second parting-off knife and / or a first and a second milling cutter, in particular a face milling cutter. The arrangement is selected such that one holder carries the machining tools for machining the two, i.e. the two profile bars that are arranged on the device and are to be welded together. It is provided that not only one parting-off knife per profile bar, but also more than one parting-off knife per profile bar is provided. As already explained, the holder has a corresponding mobility, preferably a mobility in a surface (in particular preferably parallel to the welding surface); for this purpose, corresponding CNC axes are provided for driving the holder.

[0040] The welding surface is the surface along which the actual welding takes place, i.e., the two mitered surfaces are guided into each other. The mitered surface is the diagonally cut end face of the profile.

[0041] The profile edges that border the outside of the profile bar at the end do not always run parallel to each other, and they are not always located on the same side of the profile (e.g., top or bottom). Therefore, it is advisable to provide several specially adapted parting knives per profile bar to meet the various processing requirements, especially following the profile edges.

[0042] According to the invention, at least one milling cutter, preferably a face milling cutter (for machining the miter surface), is provided on the holder for each profile bar. However, in a variant of the invention, the holder also additionally supports, for example, a finger milling cutter for each profile bar, which may be arranged coaxially with the face milling cutter or separately from it, laterally offset from it, on the holder.

[0043] An end mill differs from a face mill in that in an end mill the cutting edge(s) are arranged axially at the radial end with respect to the axis of rotation.

[0044] In contrast, in a face milling cutter, the cutting edges are provided at the axial end (relative to the rotation axis of the milling cutter) of the milling body and extend radially.

[0045] Cleverly, the chips generated by the parting-off knife or milling cutter are vacuumed away. The resulting chips are vacuumed away immediately after they are produced, effectively removing them from the heating surface and thus posing no risk of contamination to the heating surface.

[0046] Therefore, the invention provides for an extraction device for extracting the chips generated by the milling cutter and / or the parting-off knife. The proposed extraction device is preferably provided for each individual cutting tool, i.e. for the milling cutter on the one hand and for the parting-off knife on the other. The extraction devices for the various cutting tools are cleverly combined with one another in order to save space. The extraction device has, on the one hand, a suction device, i.e. an element that generates a corresponding air flow or negative pressure, similar to a blower or a turbine, and, on the other hand, a plurality of channels through which the air and thus also the generated chips are sucked in by the suction device. These channels cleverly begin in the immediate vicinity of the cutting edges in order to allow the generated chips to immediately reach the effective range of the extraction device.

[0047] According to the invention, a knife holder is provided which receives the at least one parting knife, and the knife holder is movably mounted on the holder and can be brought into at least two different positions by a drive.

[0048] In a first implementation of this proposal, only one knife holder is provided on the holder, which carries the at least one parting knife for processing one, in particular the first, profile bar. As already explained, it is advantageous if several parting knives serving different processing purposes are provided on the holder for each profile bar. Cleverly, these parting knives are mounted on a common knife holder and can thus be adjusted between at least two positions relative to the holder, which as a whole has mobility preferably in one surface (parallel to the welding surface), by means of a drive. This drive preferably acts at right angles to the direction of movement of the holder, thus allowing the at least one parting knife to be adjusted or brought into position relative to the profile bar, which preferably takes place before processing by the parting knife.

[0049] For example, after the profile bars have been clamped onto the clamping devices and positioned so that the miter surfaces are ready for machining or welding, the holder is first positioned between the miter surfaces of the two profile bars with the cutter holders not extended (and the parting knife not in the machining position, i.e., the knife holder is in the rest position). This reliably prevents unwanted machining or damage to the profile bars. If machining is then to be carried out using the parting knife, it is first moved into the working position by the drive on the cutter holder.

[0050] The knife holder carries several parting-off knives, with a first parting-off knife for the top side of the profile and a second parting-off knife for the bottom side of the profile. While the first parting-off knife is processing, the knife holder is in the working position, i.e. it is extended relative to the holder. Before the holder is then moved so that the second parting-off knife processes the bottom side of the profile, the knife holder is preferably first moved back to its rest position to prevent unwanted damage to the profile bar from the protruding parting-off knives. Once the holder has been moved and repositioned, the knife holder returns to the working position and the second parting-off knife processes the bottom of the profile.

[0051] Alternatively, third or fourth parting knives can be provided on the holder, in particular the knife holder, which are used to machine the inside or outside corner.

[0052] The design with the movable knife holder is particularly advantageous when a milling cutter is also located on the holder. The adjustability of the knife holder means that the working plane of the at least one parting knife can be adjusted in front of or behind the working plane of the milling cutter relative to the miter surface. For example, it is provided that when the knife holder is in the rest position, the cutting edges of the milling cutter are closer to the miter surface, i.e. their working plane is active and the milling cutter can, for example, perform a flat milling operation. When the knife holder is in the working position, the working plane of the parting knife (defined by the movement of the holder in the surface relative to the position of the parting knife) is closer to the miter surface than the working plane of the milling cutter and is therefore active, for example to machine the profile edge.

[0053] A particularly clever second implementation is that two separate knife holders are provided on the holder, with the first knife holder supporting the parting knives for machining the first profile bar, and the second knife holder supporting the parting knives for the second profile bar. This design consequently supports and enables symmetrical, simultaneous, and therefore efficient machining of the profile bars by the respective parting knives on the knife holders.

[0054] Preferably, the drives of the two knife holders are connected to each other, i.e., synchronized, but this does not limit the invention. It may also be advantageous to control the respective drives independently of each other if the respective processing task requires it. The drive can be implemented, for example, as an electric drive, electromagnetic, hydraulic, or pneumatic (e.g., with appropriate working cylinders).

[0055] Therefore, in a preferred embodiment of the proposal, the holder is equipped with (at least) two milling cutters, which are preferably designed as face milling cutters, and with two knife holders, which in turn carry (at least) one, preferably at least two parting-off knives. The two milling cutters are active in a first processing step. For this purpose, the ends of the profile bars are first positioned so that the milling cutters can preferably machine or produce the miter surface. The diameter of the milling cutter does not necessarily have to be larger than the width or height of the profile bar to be machined, since the holder has mobility in the welding surface. The two milling cutters machine the miter surface of the two profile bars simultaneously.Once this processing is complete, the knife holders are moved into the working position, i.e., the respective drives are activated, and the respective profile edges are then machined, preferably in parallel. Of course, the processing sequence can also be reversed, repeated, or repeated several times in alternating sequence.

[0056] Furthermore, the arrangement of the parting knives on the knife holder also allows for additional machining options. For example, the drive for positioning the knife holder is designed as a CNC axis, allowing the knife holder to move accordingly during machining and thus also the corresponding implementation of the trajectory. For example, the movement of the knife holder is combined and superimposed with the movement of the holder and / or the movement of the clamping device with the clamped profile bar. This does not preclude this CNC axis from also having two end positions for positioning the knife holder: a working position and a rest position.

[0057] Furthermore, the proposal advantageously provides for a quick-change device for the parting knife on the holder or knife mount. The provision of a quick-change device has the advantage that the parting knives can be replaced quickly and efficiently, for example, in the event of wear or when the desired cutting contour changes. A quick-change device is characterized by the fact that the parting knife is held, if possible, only in front of a retaining element that can be opened. The retaining element can be, for example, a spring lock or a screw.

[0058] Using the proposed quick-change device, it is also possible to rotate or pivot the parting knife, for example, around its longitudinal axis or the central axis perpendicular to it, thereby providing a further orientation of the parting knife's cutting edge for machining the profile bars. In particular, this allows for a simple, single-action implementation of an additional machining plane or machining edge, which would otherwise require an additional rotation axis in the device.

[0059] In a preferred embodiment of the proposal, a scanning element for detecting the profile contour is provided to the side of the parting-off knife. This design has the advantage that the parting-off knife is guided precisely, regardless of the specific design of the profile edge. It should be noted that profiles have certain dimensional tolerances and that rigid machining controlled according to fixed machining coordinates may not lead to the desired machining results with profile bars subject to tolerances. It is therefore advantageous in a variant of the proposal to provide a scanning element, for example a scanning flank or similar, next to the cutting edge of the parting-off knife, i.e. to the side of the parting-off knife, as well as slight springing of the parting-off knife at right angles to its path of movement, i.e. in the direction where the tolerance develops.The spring system ensures that the scanning element always rests reliably on the profile side, even with corresponding dimensional tolerances of the profile.

[0060] Furthermore, it is intended that the holder is movable in a surface by appropriate drives. This surface is preferably parallel to the welding surface of the profile bars to be welded. These drives (e.g. CNC axes, i.e. electric drives) are arranged orthogonally, preferably at right angles to one another. The mobility of the holder in the surface is, on the one hand, advantageous for the positioning of the individual machining tools (on the one hand the milling cutter, on the other hand the parting knife) and, on the other hand, is of course also advantageous during the execution of the machining, since the surface mobility also allows more complex machining operations to be carried out without difficulty. This mobility is achieved, for example, by having the holder on a cross-slide or similar.

[0061] Furthermore, the invention also encompasses a machine for producing a window frame or a part of a window frame, wherein the machine has at least one device as described above. The invention also encompasses machines that have a corresponding device at several corners, preferably at each corner where welding takes place. Such machines are also referred to as multi-head machines.

[0062] In this context, it is particularly noted that all features and properties described with reference to the device, as well as procedures, are also transferable mutatis mutandis to the formulation of the method according to the invention and can be used within the meaning of the invention and are considered to be co-disclosed. The same applies in reverse, meaning that structural features mentioned only with reference to the method, i.e., features related to the device, can also be considered and claimed within the scope of the device claims and are also considered part of the disclosure.

[0063] The invention is shown schematically in the drawing. It shows: Fig. 1a: in a three-dimensional view, the holder according to the invention with the knife holder in the rest position Fig. 1b: in a three-dimensional view, the holder according to the invention with the knife holder in the working position Fig. 2: in a top view, the use of the holder of a device according to the invention Fig. 3: in a three-dimensional view, the holder according to the invention in a first working position Fig. 4: in a three-dimensional view, the holder according to the invention in a second working position

[0064] In the figures, identical or corresponding elements are designated by the same reference numerals and are therefore not described again unless expedient. The disclosures contained in the entire description are analogously applicable to identical parts with the same reference numerals or the same component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure and, in the event of a change in position, is to be analogously applied to the new position. Furthermore, individual features or combinations of features from the various embodiments shown and described can represent independent, inventive or inventive solutions in themselves.

[0065] In Figure 1aThe holder 4, as used, for example, in the method or device according to the invention or the machine according to the invention, is shown schematically. The holder 4 is essentially cuboid-shaped. Drives not shown here cause the holder 4 to be movable in a plane that is parallel or identical to the welding surface (that is, the plane toward which the profile bars to be welded are welded). This is shown by the double arrows 30, 40 and 32, 42, which are orthogonal (in particular at right angles) to one another.

[0066] The holder 4 has a frame 41. The two milling cutters 5, 5a, 5b and their drives or their common drive are mounted in the frame 41. The frame 41 also indirectly accommodates the parting knives 3. The parting knives 3 are each arranged on a knife holder 6, 6a, 6b. Figure 1a , 1bThe holder 4 shown serves for the simultaneous machining of the two profile bars 1, 2, which is why the holder 4 is equipped with two cutters, i.e., two cutters 5, 5a, 5b and also two knife holders 6, 6a, 6b. Preferably, the cutters 5, 5a, 5b and also the two knife holders 6, 6a, 6b are arranged symmetrically on the large side surfaces of the holder 4.

[0067] The milling cutter 5, 5a, 5b is designed as a face milling cutter. The cutting edges 50 of the milling cutter 5, 5a, 5b are located at the axial end of the milling body and extend radially, each relative to the rotational axis 51 of the milling cutter 5.

[0068] The knife holders 6, 6a, 6b are located to the side and, when in machining use, horizontally next to the milling cutters 5, 5a, 5b. In the exemplary embodiment shown here, two parting-off knives 3, 3a, 3c are arranged on the knife holder 6a. The second knife holder 6b, which is hidden here, is also equipped with two parting-off knives 3. With respect to the rotation axis 51 of the milling cutter 5, a first parting-off knife 3a is located at the top, and the second, lower parting-off knife 3c is located on the opposite side, at the bottom of the knife holder 6a. The two parting-off knives 3a, 3c are preferably arranged symmetrically on the knife holder 6a, i.e. in the upper and lower areas.

[0069] The knife holder 6, 6a is defined by a plate edge 60, and the parting-off knives 3a, 3c protrude slightly beyond the respective plate edge 60. In the area of ​​the parting-off knives 3a, 3c, the discharge channels 70a and 70c are located behind the parting-off knives 3a, 3c in the cutting direction. These channels are part of the extraction device and reliably ensure that the cut-off chips are immediately removed and removed from the machining area. A suction device is also provided for the chips generated by the milling cutters 5, 5a, 5b, whose channels are connected to the discharge channels 70a and 70c, respectively.

[0070] A quick-change device 61 is used to reliably fasten the parting knife 3 to the knife holder 6.

[0071] At the top and bottom of the measuring holder 6 there are guide rail feet 63a, 63b, which cooperate with guide rails of the device (not shown here) in a holding and guiding manner.

[0072] Pressure lines 62a and 62b are marked, each of which is connected to a working cylinder. When pressure (pneumatic or hydraulic) is applied to the pressure lines 62a, 62b, the piston in the working cylinder expands and moves the knife holders 6, 6a, 6b from the Figure 1a shown resting position into the Figure 1b shown working position.

[0073] Figure 2 shows the second step of machining the profile bars 1, 2 with the parting knives 3. In the view selected here (in the plane spanned by the two profile bars, for example, from the inside out or from the outside in), the holder 4 is partially positioned below the two profile bars 1, 2. The knife holders 6, 6a, 6b are in the extended working position such that the respective parting knives 3, 3a, 3b can preferably act on the miter areas 11, 21 of the profile bars 1, 2.

[0074] As already explained, Figure 2 The second processing step. The first step has already been completed, as a chamfer has already been machined into the profile top surface 13, 23 of the first profile bar 1 or second profile bar 2 at the profile edge 19, 29 by the lower parting knives 3, 3c, 3d.

[0075] The lower parting knives 3, 3c, 3d are therefore intended to machine the profile edge 19, 29 on the profile top side 13, 23. In contrast, the upper parting knives 3, 3a, 3b are intended to perform a corresponding machining operation on the profile edge 19, 29 on the profile bottom side 14, 24. It is advantageous that the profile bars 1, 2 are arranged parallel to their longitudinal extension on a CNC axis, allowing for highly precise positioning. This is indicated by the arrows 10, 20, respectively.

[0076] Cleverly, the respective miter surfaces 12, 22 were previously pre-machined by the milling cutters 5, 5a, 5b and the machining step now takes place using the parting knives 3. The movement of the holder 4 and thus also the cutting movement of the parting knives 3, 3a and 3b is perpendicular to the blade plane.

[0077] Figure 4 essentially corresponds to the view in Figure 2 , only that in Figure 4 A three-dimensional view is selected. However, the editing situation is the same.

[0078] In Figure 3 However, the first step is shown, here the chamfer (a slanted surface) is machined on the upper side of the profile 13,23 with the lower parting knives 3, 3c, 3d at the profile edge 19,29.

[0079] A particular advantage of the proposal is that the two profile bars 1, 2 to be welded can be processed simultaneously using a single holder 4. Processing preferably takes place simultaneously, which increases efficiency. The high positioning capability of the profile bars 1, 2 thanks to their clamping devices is also utilized, allowing both the mitered surfaces to be machined with high precision and the profile bars to be positioned so that the profile edges 19, 29 can be machined as desired.

Claims

1. Method for welding a first profile bar made of plastic (1) with a second profiled bar (2) made of plastic, the method comprising the following steps: ▪ Provide the first profile bar (1) and the second profile bar (2); Machining of at least one profiled bar (1, 2), in particular in its mitre region (11, 21), with a parting-off knife (3), wherein the profiled edge (19, 29), which delimits the outer side of the profile, in particular the upper side (13, 23), lower side (14, 24), the inner fold or the outer corner, and the mitre surface of the profiled bar (1, 2), is machined by the parting-off knife (3), wherein a knife holder (6, 6a, 6b) is provided, which receives the parting-off knife (3) is machined by the parting-off blade (3), wherein a blade holder (6, 6a, 6b) is provided which receives the parting-off blade (3), wherein a holder (4) is provided which carries the parting-off blade (3), wherein the blade holder (6, 6a, 6b) is movably mounted on the holder (4) and can be brought into at least two different positions by a drive; ▪ Heating of the profiled bars (1, 2) at least on their mitre surfaces, wherein the profiled bar (1, 2) is additionally machined by a milling cutter (5, 5a, 5b) before heating and the chips produced by the cutting-off blade (3) or milling cutter (5, 5a, 5b) are extracted; ▪ Bringing together the mitre surface of the first profiled bar (1) with the mitre surface of the second profiled bar (2) in such a way that the heated areas of the mitre surfaces produce a material-locking connection between the first and second profiled bars (1, 2).

2. Method according to claim 1, characterised in that the profile bars (1, 2) are each provided clamped on a clamping device, and at least one clamping device with the clamped profile (1, 2) is moved during processing and / or the machining of the profiled bar (1, 2) by the cutting-off blade (3) takes place in one or more steps.

3. Method according to one of the preceding claims, characterised in that a first cut-off blade (3a) simultaneously machines the first profile bar (1) and a second cut-off blade (3c) simultaneously machines the second profile bar (2), while the profile edge (19, 29), which delimits the profile outer side, in particular the profile upper side (13, 23), profile lower side (14, 24), the inner rebate or the outer corner, and the mitre surface of the profile bar (1, 2), is machined by the cut-off blade (3).

4. Method according to one of the preceding claims, characterised in that, before heating, the mitre surface of the profiled bar (1, 2) is machined by a face milling cutter as a milling cutter (5, 5a, 5b).

5. Device for welding a first profiled bar (1) made of plastic to a second profiled bar (2) made of plastic, ▪ wherein the device has a clamping device, in particular movable along at least one spatial direction (10, 20), for holding or positioning the respective profiled bar (1, 2), and a cutting-off blade (3) for machining the mitre region (11, 21) of the profiled bar (1, 2), ▪ wherein the cut-off blade (3) is designed to machine the profile edge which delimits the profile outer side, in particular the profile upper side, profile lower side, the inner rebate or the outer corner, and the mitre surface of the profile bar (1, 2), ▪ wherein a holder (4) is provided which carries the parting-off blade (3), ▪ wherein the parting-off blade (3) is mounted so as to be movable and positionable at least along a spatial direction (30), ▪ wherein a knife holder (6) is provided which receives the at least one parting-off knife (3), and ▪ wherein the blade holder (6) is movably mounted on the holder (4) and can be brought into at least two different positions by a drive, and ▪ wherein a heating mirror is provided, which is mounted so as to be movable and positionable at least along a spatial direction (30) and is provided for heating at least the mitre surface (12, 22) of the profiled bar (1, 2) or of the profiled bars (1, 2), and ▪ wherein a milling cutter (5) is provided, which is designed to machine the profiled bar (1, 2) before heating, ▪ wherein an extraction device is provided for extracting the chips produced by the milling cutter (5) and / or the parting-off blade (3).

6. Device according to claim 5, characterised in that the holder (4) also carries at least one milling cutter (5), in particular a face milling cutter.

7. Device according to one of the preceding claims 5 to 6, characterised in that the holder (4) carries at least a first and a second parting-off cutter (3, 3a, 3b, 3c, 3d) and / or a first and a second milling cutter, in particular a face milling cutter.

8. Device according to one of the preceding claims 5 to 7, characterised in that a quick-change device (31) for the parting-off blade (3) is provided on the holder (4) or the blade holder (6) and / or a scanning element for detecting the profile contour is provided laterally next to the parting-off blade (3).

9. Device according to one of the preceding claims 5 to 8, characterised in that the holder (4) is movable in a surface (30, 32) by corresponding drives10. A machine for manufacturing a window frame or a part of a window frame, the machine comprising at least one device according to any one of the preceding claims 5 to 9.