Patent Application
20140069246
The invention relates to an apparatus for cutting of materials, producing a thin saw kerf.
Such an apparatus is known from DE 40 11 924 A1, which relates to a band-saw blade. In this apparatus, the thin saw kerf is produced in that the band saw blade narrows from a blade thickness that is otherwise essentially uniform, in the direction toward the tooth tip roots, and that the tooth tip width is not greater than the thickness of the saw blade in the region of the uniform blade thickness. However, because the saw blade must otherwise be guided in the saw kerf, it has proven to be practical to follow the saw blade, in the cutting direction, with a splitting wedge that widens the saw kerf. Furthermore, the splitting wedge must be provided with cooling channels during operation, in order to prevent the apparatus from running hot.
From the state of the art, it is furthermore known to cut wood work pieces and materials to size, in connection with the production of high-quality finished products such as parquet lamellae or flooring, by means of gate saws, circular saws or band saws. In all cases, this involves a form of chip-removing work or chip-removing cutting of materials. In this connection, circular saws conventionally work with cutting depths of approximately 150 mm, while gate saws and band saws work with cutting depths of approximately 300 mm. Within the scope of the known cutouts, the wood is therefore essentially cut up. The minimal saw kerfs that are possible in this connection lie in the range of approximately 1.4 mm.
These previously known production techniques are certainly subject to disadvantages. In the production of a usual parquet lamella having a thickness of 3 mm, approximately half the material used is used up, i.e. converted to wood waste material in the form of chips and sawdust, within the scope of the previously known cutting method, because of the problem of the significant saw kerf width and the material treatment, which is not exactly gentle. In the case of chip-removing material treatment, there is the risk that tear-outs will occur during processing of the material, for example when sawing branches. The corresponding defects must either be reworked, in complicated manner, or the wood that has been processed must be sorted out as waste. For the same reason, it is also not possible to produce particularly thin lamellae. The previously known production methods demand a lamella thickness of 2 mm and greater. In most cases, such cutting methods cannot be used for high-quality wood types. In every case, very complicated prior and subsequent processing of the treated work pieces, such as steaming of the raw wood in advance of processing and drying and smoothing of the applied veneers subsequent to processing is required. As a rule, special blade machines are used for this purpose.
The cut surfaces, which are furthermore usually very rough, must often be subsequently worked, in complicated manner.
Proceeding from this state of the art, a new type of apparatus for cutting of materials, particularly of woods, is to be developed, in which the consumption of resources is reduced, and furthermore, the prior and subsequent processing effort is also clearly less.
The solution of this task is achieved by means of an apparatus according to the main claim. Advantageous embodiments of the invention can be derived from the dependent claims 2 to 17.
Within the scope of the solution according to the invention, a preferably endless grinding saw blade having a micro-tooth system is used for cutting of materials. The micro-tooth system possesses a comparatively low cutting depth, so that while the cutting of materials takes place in chip-removing manner, the friction wear in the saw kerf produces not so much a chip but rather a saw meal. The significant advantage of the cutting, however, particularly lies in that the saw kerf is clearly reduced in size, because the tooth system is ground alternately, in the cutting direction, on the right side and the left side, to form a micro-blade, and therefore the saw kerf is alternately processed in the cutting direction, in other words simultaneously on the right and the left side, during the same cutting process. This micro-tooth system also makes it possible to work with a saw blade that has a clearly reduced thickness. In the end result, the saw kerf can therefore be configured to be clearly narrower, and the resulting material loss caused by the cutting of materials can be clearly reduced. The cut surface is worked on in clearly finer manner, and in most cases already forms a surface that can be glued, because it is in fact a ground surface, which does not require any further processing for usual applications. Furthermore, lamellae having a thickness from 0.2 mm can be produced, in other words veneers, for example, can be cut with the novel type of apparatus.
In an advantageous further development, the micro-teeth are configured to be alternately slanted, relative to one another, in the cutting direction, so that an offset endless saw blade is formed. As a result, the saw kerf is widened relative to the saw blade, so that sticking of the endless saw blade during operation is precluded.
In a concrete embodiment, the tooth pitch of the micro-tooth system amounts to 0.5 to 2 mm, and the tooth base has a depth of ≦1.5 mm.
In an advantageous embodiment of the invention, the novel type of micro-tooth system of the grinding saw blade is used in combination with a changed cutting angle, so that the micro-tooth system is set, relative to the saw blade, in such a manner that a cutting angle of preferably 40° to 60° relative to the surface of the material to be cut occurs, while in the previously known methods that have been presented in detail, a cutting angle of 90° is usual.
A further contribution to gentle cutting of materials and, in particular, for implementation of thin saw kerfs, consists in that the projection of the tooth blades of the micro-teeth relative to the saw blade amounts to only a few tenths of millimeters, preferably to 1/10 mm. If one proceeds from a saw blade thickness that has also been reduced, of 0.3 mm, a minimal saw kerf having a width of 0.4 mm, which can be implemented with the apparatus according to the invention, in contrast with the state of the art, is obtained with this configuration.
Because of the low saw blade thickness that has already been mentioned, it is practical to connect the saw blade ends for producing an endless saw band in a different way from before, because on the basis of the low material thickness, a conventional weld seam would not withstand the tension forces that occur. The saw blade ends are therefore intermeshed with form fit, at first, in the apparatus according to the invention, whereby a swallowtail tooth system has proven itself in this connection, and subsequently welded to produce material fit. In this connection, a laser welding process is to be preferred, because a connection that is particularly well able to withstand stress must be produced.
In order to allow cutting of materials by means of grinding, to a great extent, very close spacing of the micro-tooth system that has already been mentioned is required. The usual distance between the teeth of the micro-tooth system amounts to less than 1 mm. This also makes new demands on the cleaning of the saw blade that is required during the ongoing process. Conventional band saws are simply vacuumed clean, whereby the sawdust that occurs during cutting of the material is simply drawn away by way of corresponding suction channels after exiting from the saw kerf of the material to be cut. Only a residual amount caused by turbulence and static adherence remains on the processed woods, so that the machine space additionally undergoes basic cleaning at regular intervals. This method is not sufficient for the micro-tooth system that is now being used. In contrast to conventional cutting of materials, instead of sawdust, more of a saw meal or grinding meal is formed. In the narrow tooth system, an overly large proportion of saw meal would remain in the tightly dimensioned tooth base disposed between the teeth, and this would lead to heating of the saw apparatus and finally to destruction of the micro-tooth system during renewed cutting. It has proven itself, in this connection, if instead of the suction channels that have already been mentioned, a blowing apparatus is assigned to the apparatus, in such a manner that the micro-tooth system is impacted by a water/air mixture when it exits from the saw kerf of the material to be cut, in such a manner, and that the adhering saw meal can be reliably removed in this way.
In a further embodiment of the invention, it is furthermore practical if a further blowing apparatus is also disposed on the back of the saw blade, which apparatus also presses a corresponding water/air mixture into the saw kerf, at high pressure, in order to free the latter from the residues of the cutting of materials, which is a grinding process, to a great extent.
In an advantageous embodiment of the invention, the two blowing apparatuses are connected with a common supply unit and/or control unit, so that charging of the blowing apparatuses with the water/air mixture that has already been mentioned and buildup of the pressure can be synchronized and can take place with common units.
In a further embodiment, a collection apparatus for collecting the water/saw meal and wood waste mixture is disposed in the blow-off direction of the water/air mixture applied to the saw blade and to the material to be cut, whereby ideally, a filter element for pre-cleaning follows the collection apparatus in the flow-off direction of the water/saw meal mixture.
In a further improvement of the invention, the work piece guidance must also be adapted to the greater cutting precision implemented with the method and the lower tolerances that can be achieved. In this connection, it has proven itself if a usual wall or chain conveyor additionally has vacuum nozzles assigned to it, in such a manner that the work piece to be processed, in each instance, is fixed in place in the processing plane and subsequently moved relative to the saw blade. By means of the contact pressure that is implemented by means of the vacuum, flat contact of the work piece is ensured even at lower material thicknesses. A corresponding vacuum guidance is very helpful, for example, in the production of veneers.
In a further embodiment, a pivot mechanism is assigned to the roller or chain conveyor, by way of which mechanism it is ensured that the work pieces to be cut are fed to the band saw blade in such a manner that the entry angle of the micro-tooth system into the work piece to be cut is infinitely adjustable in a range from 60° to 90°.
For the case that the saw blade according to the invention, having the micro-tooth system, is structured as an endless band, this endless band is passed over two band saw rollers that are spaced apart from one another, whereby at least one of the band saw rollers is driven.
In this connection, however, the higher production precision that has already been mentioned requires that the relative position of the band saw with regard to the band saw rollers is monitored by means of a sensor system, optically or haptically, and that the inclination of at least one band saw roller can be automatically adjusted as a function of this measurement result, after an actual value/reference value comparison, by means of a corresponding angle adjustment apparatus.
For the remainder, it has proven itself if the forward movement of the saw band is monitored or if the band conveyor is provided with a reverse movement stop. Because of the low saw tooth depth of only a few millimeters, preferably of one millimeter, reverse movement of the saw band by only one millimeter would already damage the mini-tooth in question, in each instance. Accordingly, corresponding safety precautions are required.
In an alternative embodiment, the saw band having the micro-tooth system can also be clamped vertically in a saw frame and used in what is called a saw gate.
The invention will be explained in greater detail below, using an exemplary embodiment that is shown only schematically in the drawing.
This shows:
The representation in
Work pieces 5, wood work pieces in the present example, can be fed to the belt saw, by means of a belt conveyor 6. In this connection, a pivot apparatus 7 is assigned to the belt conveyor 6, in order to adjust the inclination angle of the charging belt 10 and thereby the entry angle of the micro-tooth system 3 into the work piece 5 to be cut.
Furthermore, it can be seen from the overview representation according to
Furthermore, a collection apparatus 13 for the water/saw meal and sawdust mixture exiting from the saw kerf and blown off from the micro-tooth system 3 is disposed in this region. In this connection, a filter apparatus for pre-cleaning of the mixture follows the collection apparatus 13 in the flow-off direction of the collected mixture.
As is also evident from the overview representation, one of the band saw rollers 4, 4′ has an optical sensor 15 assigned to it, with which the relative position of the circulating grinding saw blade 2 with regard to the band saw roller 4, 4′, in each instance, can be monitored. The measurement result of the sensor 15 is transmitted to a regulation and control unit that is not shown in any further detail in the overview representation, which unit in turn is connected with an angle adjustment apparatus 16, by way of which the inclination of the band saw roller 4, 4′ can be adjusted as a function of an actual value/reference value comparison.
In an alternative embodiment, not shown here, the angle adjustment apparatus 16 can also interact with a roller guide for guiding the grinding saw blade 2, whereby the relative position of the saw blade 2 with regard to the band saw rollers 4, 4′ can also be adjusted by means of pivoting rollers, as a function of an actual value/reference value comparison.
This has the advantage of significantly gentler handling of the material, with the result that the cut edges generally do not have to be processed further, i.e. particularly can be glued. Even the branch tear-outs that are otherwise usual during the sawing process can be avoided here, because the branch surface is cut when using the cutting method that is almost like grinding, and remains in the work piece 5 to be cut, without other damage.
The basic blade thickness of the grinding saw blade 2 lies at only 0.3 mm, depending on the desired cut depth, forward movement speed, and wood hardness, instead of the 0.7 to 1.4 mm that is usual otherwise. Accordingly, the projection of the blades relative to the grinding saw blade 2 is also only 1/10 mm. Otherwise, the projection is usually 3/10 to 5/10 mm.
The consequence of these dimensions is an extremely thin saw kerf. The minimal saw kerf width in the case of the novel type of cutting method amounts to only 0.4 mm, while the minimal saw kerf known from the state of the art was 1.4 mm until now. This represents a significant contribution to savings, because the material loss is correspondingly reduced. A further advantage of the gentle cutting of materials described above consists in that in this manner, even thin work pieces 5 can be worked. Thus, it is possible to process thin lamellae from a thickness of 0.2 mm using the novel type of method. In the previous state of the art, only lamellae from a thickness of 2 mm could be processed, whereby the cutting tolerances lay in a range of 0.1 to 0.2 mm. With the novel type of method, cutting tolerances in the range of 0.02 mm are achieved. In the end result, lamella having the thickness of veneer can therefore also be processed, in contrast to the state of the art.
However, the novel type of grinding sawing blade 2 requires a different production process. Because of the low basic blade thickness of only 0.3 mm that has already been mentioned, the face edges of the grinding saw blades can no longer be simply butt-welded to produce an endless band. Such a weld seam would not withstand the chipping forces that occur during the cutting process.
The novel type of saw blade according to
Furthermore, the micro-tooth system 3 differs from the previously known usual tooth system not only in the dimensions, but also in the approach angle of the cutting surface with reference to the material surface to be processed. In the sawing processing that was known until now, the cutting surfaces impacted the material to be cut at least approximately at a 90° angle, while the micro-tooth system 3 impacts the material surface at a cutting angle of at least approximately 45°.
In a further detail view, the exit region of the endless grinding saw blade 2 from the saw kerf of the work piece 5 to be processed is shown in
Furthermore, it has proven itself if a further blowing apparatus 12 is disposed in the region of the saw blade back, which also blows a water/air mixture into the saw kerf at high pressure, in order to remove the remaining sawdust of the work piece 5.
The water/dust mixture formed as the result of the blade cleaning and cut surface cleaning described is collected by means of a collection apparatus 13 assigned to this region, and drained into the sewer system, whereby a filter element follows the collection apparatus 13 in the outflow direction, in order to clean the water. Ideally, the cleaned water can be passed back to the cleaning process again, while the collected saw meal mixture is disposed of or processed further. In this method, vacuuming of the band saw as known from the state of the art can be eliminated entirely. The novel type of method of band cleaning has the advantage that the machine room remains clean otherwise, in contrast to the vacuuming method, and does not have to be cleaned at regular intervals. Furthermore, the cut material that is produced is also cleaned better than was known from the state of the art.
In a further detail view,
As is also evident from the detail view in
Furthermore, a reverse movement stop is assigned to the conveyor belt 20. Because of the extremely close-meshed tooth system, reverse movement of only a few millimeters could already damage the mini-teeth that are used.
As is also evident from
In the sectional view according to
Above, a novel type of apparatus for cutting of materials 1, particularly of wood work pieces 5, has therefore been described, which is characterized, as compared with the state of the art, in that in place of the chipping sawing method known until now, a gentle grinding sawing method is used. The novel type of method makes extremely thin saw kerfs possible, by means of the use of a special micro-tooth system 3 and a novel type of grinding saw blade 2 with a clearly reduced thickness, which kerfs can be produced with great precision, so that in this way, the loss of the material used is significantly reduced. Furthermore, the gentler material processing allows handling of work pieces 5 having a low thickness, down to processing of veneer. However, the advantages described require a novel type of production of the saw blade 2 used, a novel type of band cleaning, and high-quality blade guidance, in order to prevent the micro-tooth system 3, which is clearly more sensitive, from destruction caused by running up onto the band saw rollers 4, 4′ or caused by a possible reverse movement of the saw blade.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 002 209.0 | Apr 2011 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE2012/100112 | 4/20/2012 | WO | 00 | 10/15/2013 |
