Abstract
Aspects of the present disclosure are directed to an extrusion die for producing a plastic profile. In some embodiments, the extrusion die includes a first die plate having a flow channel for the plastic profile to be produced, at least one recess configured and arranged for accommodating exchangeable air nozzle inserts, and a connection on the outside of the first die plate. The exchangeable air nozzle inserts have an air channel with at least one air outlet nozzle. The extrusion die further including at least one air supply bore that leads from the connection on the outside of the first die plate into each of the at least one recess.
Claims
1. Extrusion die for producing a plastic profile comprising: a first die plate including a flow channel for the plastic profile to be produced, at least one recess configured and arranged for accommodating exchangeable air nozzle inserts, and a connection on the outside of the first die plate; wherein the exchangeable air nozzle inserts have an air channel with at least one air outlet nozzle; and at least one air supply bore that leads from the connection on the outside of the first die plate into each of the at least one recess.
2. The extrusion die according to claim 1, characterized in that the at least one air outlet nozzle is directed towards a region of the plastic profile to be produced.
3. The extrusion die according to claim 1, characterized in that the air channel of the exchangeable air nozzle inserts has a plurality of supply openings connected to the at least one air supply bore.
4. The extrusion die according to claim 1, characterized in that the air channel is connected to a distribution chamber.
5. The extrusion die according to claim 1, characterized in that the exchangeable air nozzle inserts have a depression communicating with the air channel and forming the at least one air outlet nozzle.
6. The extrusion die according to claim 1, characterized in that each of the exchangeable air nozzle inserts are positioned in the at least one recess.
7. Extrusion method of plastic profiles with an extrusion die with a flow channel for forming a profile, the method including the following steps: providing a first die plate including recesses for receiving air nozzle inserts, the air nozzle inserts including air outlet nozzles; blowing air through the air outlet nozzles; directing the blown air at an angle between 0° and 45° onto the profile strand emerging from the extrusion die.
8. The extrusion method of claim 7, wherein the step of blowing air further includes utilizing an air supply bore for blowing the air from an outside of the first die plate to each recess.
9. The extrusion method of claim 7, characterized in that the blowing air is at room temperature.
10. The extrusion method of claim 7, characterized in that the blowing air is preheated to a temperature between 200° C. and 600° C.
Description
[0016] In the following, the invention is explained in more detail by means of exemplary embodiments, wherein:
[0017] FIG. 1a shows an extrusion die according to the invention with 3 air nozzle inserts in an oblique view;
[0018] FIG. 1b shows a section of the extrusion die of FIG. 1a in a frontal view;
[0019] FIG. 1c shows a section of the extrusion die from FIG. 1a, but with simplified contours, in an oblique view;
[0020] FIG. 2 shows a detail from FIG. 1c in sectional view in the center plane of the air nozzle insert in oblique view;
[0021] FIG. 3 shows a first air nozzle insert according to the invention and according to FIG. 1c in oblique view;
[0022] FIG. 4 shows a sectional view of the air nozzle insert according to FIG. 3 in oblique view;
[0023] FIG. 5 shows a further sectional view of the air nozzle insert according to FIG. 3 in oblique view;
[0024] FIG. 6 shows a further sectional view of the air nozzle insert according to FIG. 3 in oblique view;
[0025] FIG. 7 shows a second air nozzle insert according to the invention in oblique view.
[0026] FIG. 1a generally shows an extrusion die 20 having a first die plate 1 and a die body consisting of several additional die plates 2. This extrusion die 20 is heated by heating plates 21. It is designed for the extrusion of a wing profile 23. The wing profile 23 has three profile extremities for which three air nozzle inserts 6 are embedded in the front face of the first die plate 1. Each air nozzle insert 6 is supplied with blowing air via heating probes 8. The supply bores 11 for the blowing air located in the first die plate 1 must not collide with the screw connection 22 or other built-in components.
[0027] FIG. 1b shows a section of the extrusion die 20 from FIG. 1a in a frontal view. The supply bores 11 open into the air nozzle inserts 6, 6′, 6″ at different positions. The air nozzle insert 6′ has only one air outlet nozzle 9, the air nozzle inserts 6″ each have two air outlet nozzles 9. Each air outlet nozzle 9 directs the air to a specific point of the profile strand 3 of the wing profile 23 exiting the extrusion die 20. By exchanging or reworking the air nozzle inserts 6, the air jet can be directed to desired points of the profile strand 3 with little effort.
[0028] FIG. 1c shows in detail the upper right-hand corner area of extrusion die 20 in an oblique view against extrusion direction E, wherein the geometry of the profile strand 3 is slightly modified compared to the wing profile 23 and the geometry of the first die plate 1. The first die plate 1 seals the extrusion die 20 in the direction of extrusion. From this first die plate 1, the profile strand 3 emerges as a melt with a dough-like consistency in extrusion direction E. Only a part of profile strand 3 is shown. The single-walled profile segment 4 protrudes from profile strand 3 and is formed in a hook-shaped manner in this case. The air nozzle insert 6 is embedded flush in the front face of the die plate 1 and can be fixed with the countersunk screw 7. The air nozzle insert 6 is supplied with room air or heated air via the heating probe 8. The two air outlet nozzles 9, which are designed as holes in the air nozzle insert 6, are used to blow one air jet each at the edges 5 of the single-walled profile segment 4, which is symbolized by two arrows 10.
[0029] The intensity of the air jet as well as its temperature can be varied within wide limits by means of a control device, which will not be discussed in detail. The flow velocity of the air jet 10 can be varied by pressurizing the heating probe 8 with compressed air at different pressures in the range of 0 to 4 bar. The cross-sections and lengths of the actual air outlet nozzle 9 as well as in the supply line in the air nozzle insert 6 and in the die plate 1 limit the air flow rate to reasonable values, max. approx. 0.4 Nm.sup.3/min. The diameters in the supply line are deliberately kept “small”, approximately from 0.8 to 2 mm. The temperature of the blowing air can be adjusted within a range from room temperature to 600° C. If necessary, the blowing air can also be cooled, for which purpose the cold air is sucked in with a compressor from an air heat exchanger, which can be cooled down to −40° C.
[0030] In FIG. 2, a detail from FIG. 1c is shown in sectional view. The blowing air is introduced from the heating probe into the first die plate 1 and is led via supply bores 11 to the distribution chamber 12, which is located in the air nozzle insert 6. The supply bores have a small diameter in order to limit the throughput of the blowing air and to keep the temperature exchange between blowing air and die plate low. The single-wall profile segment 4 is impinged in a small area by an air jet 10, which exits from the air outlet nozzle 9. This air outlet nozzle 9 is supplied with the blowing air from the distribution chamber 12. The cross-section of the air outlet nozzle 9 as well as its angular position to the extrusion direction E can be varied within wide limits: Bore diameters between 0.8 and 3 mm as well as angles between 0 and 45°, preferably between 10 and 25°, have proven to be very effective.
[0031] FIG. 3 shows a first, non-exclusive embodiment of the air nozzle insert 6 (view diagonally against the extrusion direction E) according to the invention. The air nozzle insert 6 has three supply bores 11 as standard: one on the right side and one each on the upper and lower side of the air nozzle insert (relative to the position of the air nozzle insert in this Fig.). Countersinking of the supply bores is advisable so that the supply bore in the nozzle can have large tolerances with respect to the point of impact. Two mounting chamfers 13 are used to fix the air nozzle insert with a countersunk screw 7. These mounting chamfers 13 allow many different positions for the countersunk screw 7 so that collisions with other design elements can be safely avoided. Not shown is a “trigger thread” which is countersunk in the front side of the air nozzle insert 6, between the two mounting chamfers. The dimension I for the depth of the air nozzle insert 6 is freely selectable within wide limits, but is limited at the top by the thickness of the first die plate 1, minus approx. 2 mm. Depths between 15 and 18 mm have proven to be effective. Up to this point the description corresponds to a basic form of the air nozzle insert, which can be uniformly designed for almost all applications. Only the two holes that form the air outlet nozzles 9 go beyond the basic form.
[0032] FIG. 4 shows a sectional view of the air nozzle insert 6 according to FIG. 3. The sectional plane is at the height of the bore for the upper air outlet nozzle 9. The outlet nozzle is supplied with blowing air from the inlet side of the distribution chamber 12. The bore has an angle of approx. 15° to the extrusion axis, so that the profile segment 3 is subjected to an oblique flow.
[0033] FIG. 5 shows another sectional view of the air nozzle insert 6 according to FIG. 3. The sectional plane is at the level of the supply bore 11 for the blowing air. The distribution chamber 12, which in this case is a blind hole, is supplied with blowing air via this bore.
[0034] FIG. 6 shows another sectional view of the air nozzle insert 6 according to FIG. 3. The sectional plane is at the level of the bore for the lower air outlet nozzle 9. The description corresponds to that of FIG. 4. In addition, the lower air supply bore 11 for the blowing air can be seen.
[0035] FIG. 7 shows another embodiment of an air nozzle insert 6 in an oblique view (in extrusion direction E). The distribution chamber 12 for the blowing air is designed as a slot. Upstream, in relation to the direction of extrusion, this slot is continued around the edge, in installation position towards profile segment 4, in FIG. 7 thus to the right, by a flattening. The two supply bores 11, which are provided in the first embodiment according to FIG. 2 on the upper and lower side, can be omitted here because the supply bore 11 of the nozzle opens into the slot which forms the distribution chamber 12. This basic shape has the advantage that the air outlet nozzles 9 can be manufactured both as an inclined bore and as a channel-shaped channel on the outer circumference of the air nozzle insert 6, which is bounded by the wall of the receiving groove when installed. Such channels can be easily made and reworked by means of a handsaw or file without the aid of a machine. The disadvantage that the air jet 10 is now directed parallel to the extrusion direction is hardly noticeable, since the outlet nozzle is positioned closer to the profile segment 4.
