DE19854932C2 - External vacuum calibration - Google Patents

Description

The invention relates to an external vacuum calibration for plastic.

It is in the manufacture of plastic products or profiles by extrusion necessary and usual, one in the production line after the extruder tool Calibration should provide the dimensional accuracy of the cross section of the extruded Product ensures and at the same time for cooling the thermoplastic Plastic extruded product is used.

A so-called vacuum external calibration, which is used for Cooling and calibration of an extruded plastic product on its Outside surface serves. In practice, such an external vacuum calibration exists two blocks connected to two surfaces where the blocks are connected to each other Formation of a bilaterally open calibration channel are processed. The two blocks consist of a hard, wear-resistant steel. To do that for calibration necessary concerns of the extruded plastic material on the inner surfaces or To reach calibration areas of the calibration channel, it is necessary in every block provide vacuum channels opening the calibration channel. Furthermore, it is necessary Provide a large number of cooling channels in each block, separated from the cooling medium (Cooling water) are flowed through. This training means a considerable amount Manufacturing effort, because a large number of holes and sometimes also themselves intersecting holes in the block of hard material with high precision must be introduced.

It is also known in particular (DE 28 09 386 A1) which the cooling medium flows through To design cooling chambers of a vacuum external calibration in a plate-like manner using plates with corresponding recesses in a Axis direction perpendicular to the longitudinal extension of the calibration channel open at both ends are subsequently provided in a stack-like manner.  

Finally, it is known (DE 40 28 115 A1) for an external vacuum calibration for extruded plastic profiles in the pull-off device of the respective profile one behind the other to provide several calibration units and these floating on a guide to store. Each calibration unit consists of one that is open at both ends Block having calibration channel. The calibration units are different from each other spaced.

The object of the invention is to demonstrate a vacuum external calibration that this Avoids disadvantages and with much less effort and with much lower costs can be realized. To solve this task, a vacuum External calibration designed according to the features of claim 1.  

In the invention, there is at least one that forms the vacuum external calibration Block of a variety of sheets or plates that stack to form the block are interconnected. Recesses are then provided in the plates, from the first complement each other to form the calibration channel and the second and third the least a cooling channel and a vacuum channel with the vacuum outlet openings form. By structuring the plates appropriately and by placing them close together adjacent plates ensure that through the second or third recesses the at least one closed and only at a coolant inlet and Cooling medium drain open cooling channel and the at least one vacuum channel and corresponding vacuum openings are formed.

A particular advantage of the training according to the invention is u. a. in that by the stack-like formation of the at least one block of the calibration device Cooling channels right up to the ends of the calibration channel and in particular also be trained to reach directly to the front end of this channel can, so that cooling directly at the ends and in particular at front end of the calibration channel is possible. The axial distance between the planes and in particular also the front end of the calibration channel and that on this level following cooling channel can be kept as small as this the strength of the used material allows. This distance is only a few, for example Millimeters (e.g. 2 mm). In the conventional formation of a vacuum External calibration consisting of a solid block in which the cooling channels pass through Holes are realized, however, it is necessary to drill these holes in particular also at the front and rear end of the block or the calibration channel To stopper having a certain length, for example a length of have at least 10 mm. This means that the distance between the plane of the front or rear end of the calibration channel and the first cooling channel of this Corresponds to the length of the plug and thereby the external calibration at the front end of the Calibration channel has insufficient cooling, with the result that the hot plastic of the extruded product or profile on the external calibration can stick.

Developments of the invention are the subject of the dependent claims. The invention will explained in more detail below with reference to the figures. Show it:

Figure 1 shows an extruder with a profile tool and a subsequent vacuum external calibration according to the prior art.

Fig. 2 is a simplified representation and in side view a vacuum calibration outer according to the invention;

FIGS. 3 and 4 are cross-sections through the outer vacuum calibration of Figure 2 in two different cross-sectional planes.

Figures 5 and 6 in a schematic representation sections corresponding to lines II and II-II.

Fig. 7 representation similar to Figures 3 and 4 a cross section through a further possible embodiment of the invention.

Fig. 8 shows a vacuum plate for use in the vacuum external calibration of Fig. 7;

Fig. 9 shows a cooling plate for use in the vacuum external calibration of Fig. 7;

Figure 10 shows an intermediate plate for use in the vacuum external calibration of Figure 7;

Fig. 11 shows a connection plate for use in the vacuum external calibration of Fig. 7;

Fig. 12 in a very simplified representation, a vacuum external calibration, which is formed by two axially adjoining individual calibrations.

In the figures 1 is an extruder with an attached extruder or profile tool 2 for producing a plastic profile strand 3 , which is shown in the figures for the sake of simplicity as a two-chamber hollow profile 4 with an outer rectangular cross section, the profile naturally also having any other shape, in particular can also have a much more complicated shape. The extruder or profiling tool is followed by a so-called external calibration in order to cool the plastic and to ensure the predetermined external dimensions of the profile strand 3 , in which the extruded profile strand 3 is brought to the exact external dimensions and at the same time cooled.

In FIG. 1, a hitherto conventional vacuum outer Calibration 5 is shown. This calibration 5 is carried out in two parts and consists of a lower part 5 'and an upper part 5 ", which are detachably connected to one another and form the calibration channel 6 between them, through which the profile strand 3 is guided for calibration and cooling. For cooling of the extruded section 3 , a plurality of cooling channels 7 are formed both in the upper and in the lower part 5 'or 5 "of the calibration 5 made of metal, through which a flow of cooling water flows. Furthermore, a plurality of vacuum channels 8 are provided in the upper and lower parts 5 ′ and 5 ″, each of which opens with a slot-like opening 9 on a calibration surface 10 delimiting the calibration channel 6. The vacuum channels 8 are each connected to one via a distributor chamber 11 a vacuum source leading connection 12 is connected, so that the material of the profile strand 3 is sucked against the calibration surface 10 via the vacuum at the openings 9 and thus the optimal calibration and dimensional accuracy of the profile strand 3 or the profile is achieved.

The two parts 5 'and 5 "are blocks of high-hardness steel, each block being machined accordingly on an outer surface to form the calibration channel 6 and, moreover, provided with a large number of bores to form the cooling channels 7 and the vacuum channels 8 , of which at least the transverse 3 (longitudinal axis L) and thus perpendicular to the plane of this figure, holes for the cooling channels 7 respectively on both ends not shown in the Fig. 1 to the axis of the extruded profile, the cooling water flow and cut rewind forming holes, which then with the cooling water inlet 13 and the cooling water inlet 14. This means that a large number of different, partially intersecting bores have to be provided in an extremely hard material, and this also means that the bores forming the cooling channels 7 and those not shown represent the cooling water inlet and the cooling water return Longitudinal holes must be closed at both ends on the outer surface of the respective block.

The Fig. 2 et seq show a vacuum calibration outside 15 according to the invention. This vacuum calibration is again formed in two parts, ie it consists of a lower part 15 'and an upper part 15 ", which are detachably connected to one another by suitable means, so that the external vacuum calibration is opened for purposes of inspection, cleaning, repair, etc. The special feature is that each part 15 'or 15 "consists of a plurality of sheets or plates 16 or 17 , which are generally indicated in FIG. 2 with 16 and each in a plane perpendicular to the longitudinal extension L. the vacuum external calibration 15 are arranged. The plates 16 of the lower part 15 are firmly connected to one another by means of clamping bolts 17 to form a block or package, in which adjacent plates each lie tightly pressed against one another. In the same way, the plates 17 of the upper part 15 "are connected to one another by means of clamping bolts 19 to form a package or block.

The plates 16 and 17 are machined on the mutually adjacent sides of the lower part 15 'and upper part 15 "in such a way that they form the calibration channel 6 , as is clearly shown in FIGS. 3-6. Each plate 16 and 17 accordingly has a recess 20 or 21 , wherein the recesses 20 of all the plates 16 complement each other to form the part of the calibration channel 6 formed in the lower part 15 'and the recesses 21 in the plates 17 form the part of the calibration channel 6 formed in the upper part 15 ".

In the plates 16 and 17 are continued to form the in planes perpendicular to the longitudinal axis L disposed cooling channels recesses 22 and to form the perpendicular also in planes to the longitudinal axis L lying vacuum channels recesses 23 are provided, the latter forming a one slit nozzle opening portion 23 'in the Recess 20 or 21 open out, again on the calibration surface 10 of the calibration channel 6 formed by these recesses.

Holes 24 and 25 are also provided in the plates 16 and 17 , respectively, into which the recesses 22 each end with their ends. When the vacuum external calibration 15 is fully assembled, all the bores of all the plates 16 and 17 are congruent. Likewise, all the bores 25 , so that the bores 24 form a longitudinally extending channel L for supplying the cooling water, which is connected to the cooling water inlet 13 , and the bores 25 form a longitudinally extending channel L for discharging the cooling water, which is connected to the Cooling water drain 14 is connected. The recesses 23 each open into a bore 26 with their end located away from section 23 '. The holes 26 are in turn arranged so that these holes in the plates 16 and 17 form a continuous, in the longitudinal direction L extending vacuum distribution channel which is connected via the vacuum connection 12 to the vacuum source, not shown.

It goes without saying that the recesses 22 and 23 and the associated bores 24 - 26 in the plates 16 and 17 are provided in such a way that there is no mixing of the various media (cooling water and vacuum). To achieve this there are provided in FIGS. 3-6 embodiments illustrated by the plates 16 and 17 each have two different embodiments, shown in FIGS. 3-6 respectively with 16 a and 16 b or 17 a and 17 b are referred to, and which alternate in the longitudinal direction L in the block 15 'and 15 "respectively. in all of the disks 16 a, 16 b and 17 a, the holes 24-26 are provided in each case 17 b.

In the plates 16 a and 17 a, recesses 22 are provided on a first side as groove-like depressions. In the plates 16 b and the vacuum channels forming recesses 17 b 23 is provided with en portions 23 'respectively to a first side of the groove-like recesses. The plates 16 a and 16 b or 17 a and 17 b are then connected to one another so that the recesses 22 and 23 in one plate are each covered by the second side of an adjacent plate, which does not have such a recess, such as this is shown in FIGS. 5 and 6 in different longitudinal sections for two adjacent plates.

The recesses 23 forming the vacuum channels, with their sections 23 ', are provided in particular where surfaces for the extruded section 3 with high dimensional accuracy are required.

The plates 16 and 17 of the external vacuum calibration 15 can be manufactured very easily and inexpensively with the necessary recesses and bores. This results overall in an inexpensive and simple manufacture of the vacuum external calibration 15 . It is no longer necessary to provide a large number of holes in a block made of a hard material.

Furthermore, in the invention there is the possibility of producing the plates 16 and 17 each from a different material, for example the plates 16 a and 17 a for cooling from a metal having good thermal conductivity, e.g. B. made of brass. The plates 16 b and 17 b, on which the vacuum outlet nozzles are formed by the sections 23 ', then consist of a hard steel which has a particularly high wear resistance, but does not have an optimal thermal conductivity.

A further significant advantage is also that at the ends of the vacuum calibration outer 15 and in particular also at the extruder facing the front end of a cooling by means of the plates 16 a and 17 a possible immediately there.

There is also the possibility, for example, of providing the recesses 22 forming the cooling channels in such a way that these channels extend directly to the calibration surface 10 or to the recesses 20 or 21 , so that extremely short cooling distances or paths result.

At both ends, the packages formed by the plates 16 and 17 or the lower part 15 'and the upper part 15 "are each provided with an end plate or clamping plate 27 or 28 , which also contain connection and distribution channels and of which at In the illustrated embodiment, the plate 27 has the cooling water inlet 13 and the plate 28 has the cooling water outlet 14 and also the vacuum connection 12 .

In the embodiment described above, it was assumed that the recesses 22 and 23 are each designed as an open groove on a surface side of the plate in question. Basically, however, there is the possibility of designing the recesses 22 and 23 as continuous slits, it then being ensured, of course, by appropriate structuring or choice of the course of the recesses that no surface areas separated from the rest of the respective plate 16 or 17 by the course of the recesses 22 and 23 arise.

If the recesses 22 and 23 are designed as continuous slots, it is further ensured by the course of the recesses 22 in the plates 16 a and 17 a and by the course of the recesses 23 in the plates 16 b and 17 b Placing the plates 16 a and 16 b or 17 a and 17 b on top of one another does not overlap the recesses 22 and 23 , but rather each recess 22 in a plate 16 a or 17 a by surfaces of two adjacent plates 16 b or 17 b or an end plate 27 or 28 is covered on both sides, which (surfaces) do not have the recesses 23 . The same applies vice versa for the recesses 23 of the plates 16 b and 17 b, which are also closed on both sides by surfaces of adjacent plates 16 a and 17 a.

FIGS. 7-11 show a further possible embodiment of a vacuum calibration 15 a according to the invention. This calibration in turn consists of the lower part 15 a 'and the upper part 15 a ", the upper part and lower part being composed of a plurality of plates which are arranged with the planes of their surface sides perpendicular to the longitudinal extension of the calibration 15 , as described above for the vacuum -Exterior calibration 15 has been described.

As far as elements of the vacuum calibration 15 a correspond to those of the vacuum calibration 15 , these are again provided with the same reference numerals, ie although in the vacuum calibration 15 a or in the upper part 15 a 'and the lower part 15 a "the arrangement and / or the structuring of the individual recesses and bores differs from the vacuum external calibration 15 , the same reference numerals are used in FIGS . 7-11 for the bores and recesses as in FIGS. 2-6, insofar as these recesses and openings have the same function have, however, each with the addition "a".

FIGS. 9-11 show the plates 30, 31, 32 and 33 that make up the lower part 15 a 'composed of the vacuum calibration device 15 a. Here, the plate 30 forms a vacuum plate with the recess 23 a for the vacuum channel, this recess 23 a being designed as a continuous opening in this embodiment. Furthermore, in the plate 30 , as in the other plates 31 , 32 and 33, the recess 20 a for the calibration opening and, inter alia, also holes 24 a and 25 a are provided, which are in the stack or lower part formed by the plates 30-33 15 a 'form the channels for supplying and removing the cooling medium.

The plate 31 forms the cooling plate in which the recess 22 a is provided, again in the embodiment shown as a continuous opening. In the plate 31 , a bore 26 a is also provided, which together with the corresponding bores or recesses of the other channels forms the vacuum channel.

32 with an intermediate plate is designated, which is provided in this embodiment between two in the longitudinal direction of the outer calibration 15 a adjoining plates 30 and 31 . This intermediate plate 32 does not have the recesses 22 a and 23 a, but inter alia the holes 24 a, 25 a and 26 a. By means of the intermediate plates 32 , the cooling channels or vacuum channels formed by the recesses 22 a or 23 a are closed on both sides in the axial direction of the external calibration 15 a. With 33 in Fig. 11 outer terminal plate is shown, which has the function explained in more detail below.

As shown in FIGS. 7-11, a special feature of the vacuum calibration 15 a is that a narrow projection 34 extends into the part of the calibration channel 6 formed by the recess 20 a, which extends like a web over the entire length of the calibration channel 6 and is enclosed on three surface sides by the profile to be calibrated. In the region of this projection 34 , intensive cooling of the profile strand 3 is also necessary. For this reason, a cooling channel 35 is formed in the projection 34 and extends over the entire length of the calibration channel. Because of the small dimensions of the projection 34 , it is not possible to implement this cooling channel by recesses in the cooling plates 31 alone. Rather, the projection 34 and the associated cooling channel 35 is realized in that each plate 31-33 has an extension 34 a projecting into the recess 20 a, which is provided with an opening 35 a which is closed on the circumference but passes through the plate, whereby all extensions 34 a to the strip-like projection 34 and all openings 35 a to the axial cooling channel 35 complement each other. In the terminal plate 33 is provided in the local store 35 a which open recess 36 which opens into a bore 37, which then the terminal for supplying or discharging the cooling medium through the recess 36 into the recesses 35 a formed cooling channel 35 or forms for removing the cooling medium from this cooling channel. In each case one connection plate 33 is then provided, for example, on the respective outer clamping plate 27 or 28 .

Basically, in the embodiment shown in FIGS . 7-11, there is also the possibility of dividing the cooling channel 35 in the longitudinal direction of the external calibration 15 a into a plurality of axially adjoining sections, a connection plate 33 being provided at the beginning and at the end of each section . In the embodiment described above, the axial cooling channel 35 is provided in the strip-like projection 34 . In other spatially confined areas, which do not permit, for example, from the recess 22 or 22 a cooling channel formed in the respective cooling plate, but still require a more intensive cooling, such axial cooling channels can be provided.

38 are shown in FIGS. 7-10 still referred fitting bolt, which serve for centering the individual plates 30-33, and each 'these plates extend through mating openings 38 therethrough.

As shown in FIG. 12, the fitting bolts 38 can be longer than the respective block formed by the plates 30-33 or the respective lower part 15 a 'and upper part 15 a ".

In the embodiment shown in FIG. 12, the lower dowel bolts 38 with this greater length are designed such that two axially consecutive, axially aligned lower parts 15 a 'are provided on the common dowel bolts 38 at a distance from one another. The associated upper parts 15 a "are each independent of one another. This design results in a vacuum outer calibration arrangement with two axially or cascade-like successive and spaced apart vacuum outer calibrations. Two spacer sleeves 39 are provided on the two dowel pins 38 , which distance between the two vacuum external calibrations 15 a ensures.

The invention has been described above using exemplary embodiments. It goes without saying that numerous changes and modifications are possible, in particular also with regard to the design and / or the course of the recesses forming the cooling channels and / or vacuum channels. Furthermore, it is also possible to provide additional channels by appropriate structuring of individual plates 16 or 17 , for example a channel for introducing a barrier or fresh water into the calibration channel 6 , in order to prevent and thus also prevent any leakage of cooling water in this calibration channel prevent contaminants from the cooling water circuit from entering the calibration channel, which lead to an impairment of the surface of the profile strand 3 produced. Furthermore, additional suction channels etc. can also be formed by appropriate structuring of individual plates 16 and 17 .

Reference list

1

Extruder

2nd

Extruder or profile tool

3rd

Profile strand

4th

profile

5

Vacuum external calibration according to the state of the art

5

'Lower part

5

"Top

6

Calibration channel

7

Cooling channel

8th

Vacuum channel

9

Vacuum outlet nozzle

10th

Caliber area

11

Distribution channel

12th

Vacuum connection

13

Cooling water inlet

14

Cooling water drain

15

,

15

a vacuum external calibration according to the invention

15

',

15

a 'lower part

15

",

15

a "top

16

,

16

a,

16

b Sheet or plate

17th

,

17th

a,

17th

b Sheet or plate

18th

,

19th

Clamping bolt

20th

,

20th

a,

21

Recess (calibration opening)

22

,

22

a recess (for cooling duct)

23

,

23

a recess (for vacuum channel)

23

' Section

24th

,

25th

,

25th

a,

26

,

26

a hole

27

,

28

Clamping or end plate

30-33

plate

34

ledge-like lead

35

Cooling channel

34

a process

35

a opening

36

Recess

37

opening

38

Dowel pin

38

'Fitting hole

39

Spacer sleeve

Claims (20)

1. Vacuum external calibration for plastic, with at least one block ( 15 ', 15 "), in which at least one calibration channel ( 6 ), which extends in a longitudinal direction (L) of the external calibration, is formed, with at least one cooling channel in the block ( 15 ', 15 ") for a cooling medium flowing through this channel and with at least one first connection ( 13 ) serving for supplying the cooling medium to the at least one cooling channel, with a second connection ( 14 ) serving for removing the cooling medium from the cooling channel and with A plurality of vacuum openings ( 23 ') opening into the calibration channel ( 6 ) on a calibration surface ( 10 ), which can be connected to a vacuum source via at least one vacuum channel ( 23 ) in the block ( 15 ', 15 "), characterized in that the block ( 15 ', 15 ") is formed from a plurality of plates ( 16 , 17 ) which adjoin and connect to one another in a stack-like manner so that the plates are first Have recesses ( 20 , 21 ) which, in the case of plates ( 16 , 17 ) connected to one another to form a block, form the calibration channel ( 6 ) such that the at least one cooling channel has second recesses ( 22 ) in the plates ( 16 , 17 ) and the Vacuum outlet openings and the at least one vacuum channel are formed by third recesses in the plates, and that the plates ( 16 , 17 ) are structured for this purpose in such a way that in the stack or block ( 15 ', 15 ") formed by the plates that of the second At least one cooling channel formed in recesses ( 22 ) are separated from the vacuum outlet openings and from the at least one vacuum channel, which are formed by the third recesses ( 23 , 23 '). 2. Vacuum external calibration according to claim 1, characterized in that the second and third recesses ( 22 , 23 , 23 ') extend perpendicularly or transversely to the longitudinal axis (L). 3. Vacuum external calibration according to claim 1 or 2, characterized in that in some of the plates ( 16 , 17 ) to form further, in the at least one calibration channel ( 6 ) opening auxiliary channels, for example for introducing sealing water and / or for sealing water suction at least a fourth recess is provided which opens into the at least one first recess ( 20 , 21 ). 4. Vacuum external calibration according to one of the preceding claims, characterized in that the third recess ( 23 , 23 ') and / or the fourth recess in each case opens into the first recess ( 20 , 21 ) forming the calibration channel ( 6 ). 5. Vacuum external calibration according to one of the preceding claims, characterized in that the plates ( 16 , 17 ) are each arranged in planes transverse or perpendicular to the longitudinal axis (L). 6. External vacuum calibration according to one of the preceding claims, characterized in that in the plates ( 16 , 17 ) bores ( 24-26 ) are provided, which are connected to one another in the case of a stack or block ( 15 ', 15 ") to supplement channels for supplying and discharging the cooling medium and / or for supplying the vacuum and / or for supplying and / or discharging an auxiliary medium, for example for supplying and / or discharging sealing water, and that the second and / or third and / or fourth recesses in the plates ( 16 , 17 ) each open into a bore ( 24-26 ). 7. Vacuum external calibration according to claim 6, characterized in that the channels formed by the bores ( 24-26 ) extend in the longitudinal direction (L). 8. Vacuum external calibration according to one of the preceding claims, characterized in that the at least one block ( 15 ', 15 ") of plates ( 16 , 17 ) of at least one first type ( 16 a, 17 a) and of plates ( 16 , 17 ) of a second type ( 16 b, 17 b) are formed, the plates of the first type ( 16 a, 17 a), the second recesses ( 22 ) for forming the at least one cooling channel and the plates of the second type ( 16 b, 17 b) have the third recesses ( 23 , 23 ') for forming the vacuum openings and the at least one vacuum channel. 9. Vacuum external calibration according to one of the preceding claims, characterized in that the second recesses ( 22 ) each extend between two bores ( 24 , 25 ). 10. Vacuum external calibration according to one of the preceding claims, characterized in that the third recesses ( 23 ) each open into a bore ( 26 ). 11. Vacuum external calibration according to one of the preceding claims, characterized in that the plates ( 16 , 17 ) each consist of metal. 12. External vacuum calibration according to one of the preceding claims, characterized in that the plates ( 16 , 17 ) each consist of different material. 13. Vacuum external calibration according to one of the preceding claims, characterized in that the plates of the first type ( 16 a, 17 a) each consist of a material, for example of a metal or a metal alloy with high thermal conductivity. 14. Vacuum external calibration according to one of the preceding claims, characterized in that the plates of the second type ( 16 b, 17 b) are each made from a wear-resistant material, for example from a high-strength steel or steel alloy. 15. Vacuum external calibration according to one of the preceding claims, characterized in that some plates are of a third type, which are arranged as separating plates between a plate of the first type ( 16 a) and a plate of the second type ( 16 b). 16. Vacuum external calibration according to one of the preceding claims, characterized by a two-part design of the calibration ( 15 ) consisting of a lower part ( 15 ') and an upper part ( 15 "), wherein the upper and / or lower part from that of the plates ( 16 , 17 ) formed block or stack. 17. Vacuum external calibration according to one of the preceding claims, characterized in that overlapping openings ( 35 a) are provided to form at least one axial cooling channel ( 35 ) in the plates ( 31-33 ). 18. Vacuum external calibration according to claim 17, characterized by at least one connecting plate ( 33 ) having a recess ( 36 ) leading away from the opening forming the cooling channel, said one the cooling channel ( 35 ) with a feed or discharge ( 37 ) for the Coolant connects. 19. Vacuum external calibration according to one of the preceding claims, characterized by fitting bolts ( 38 ) which extend from the adjustment of the plates ( 30-33 ) through fitting openings of these plates. 20. Vacuum external calibration according to claim 19, characterized in that two external calibrations or blocks ( 15 ', 15 a', 15 ", 15 a") are provided on common dowel pins ( 38 ) in the axial direction one after the other.