DE19509653C1 - Parquet strip mfg. process - Google Patents

Abstract

The method uses a series of cutting devices, which repeatedly cut thin strips from squared timber. The thickness of the thin strips cut by each individual cutting device (1) is determined separately.The actual detected value is compared to a reference value for the strips cut by this device. The variation generates a signal, which is used to correct the blade setting for subsequent cutting. The actual thickness of a strip is calculated as a differential of the thickness of the remaining timber (5) before and after cutting.

Description

The invention relates to a method and a system according to the preambles of claims 1 and 7 for cutting without cutting thinner Boards from a square timber. Such a method is u. a. to generate thin boards used for the top layer of floor covering laminates.

The cutting-free production of thin boards from a square timber is known. It is also known that the thickness of the did not produce thin boards as when sawing preferably dry wood can be predetermined relatively accurately, since in the cutting process Wood processed in a moist and preferably still heated state and various wood parameters as well as machine parameters affect the thickness of a board produced.

These circumstances mean that when a square timber is completely divided certain thickness, from which a number of thin boards are produced should, whose summed thicknesses correspond to the thickness of the squared timber, nevertheless the last piece of board left can be left, the thickness of which is by no means the Target specification corresponds more so that it is without the provision of any special Measures must be discarded.

DE 40 26 346 A1 describes a method for solving this problem described in which the thinner after separating one or more Boards remaining residual squared timber measured in its thickness and then tried the setting of the machine parameters relevant to the cutting thickness to change that the remaining squared timber as evenly as possible into the rest  Number of thin boards that are still to be produced from it, so that there is no unused board left. This The approach is based on philosophy, as the desired goal Divide the squared timber completely and without loss into usable thin boards, with possible variations in the thickness of the thin boards produced in Purchase. This is in the case of procedures where the boards follow the drying process following the cutting because of the occurring dimensional changes of the wood are then equalized must be acceptable within certain limits. What is essential about this process is that the result of the measurement of the residual squared timber is solely in the further division of one or at best a certain group of Squared timber flows, their processing under the same conditions was started. The method is preferably also used in systems with only a cutting device or a sequence of a few cutting devices, For example, two machines are used in which the square timber after the Pass through one or the small group of cutting devices in its remaining thickness is measured and then passed through the Cutting system to be further divided. With this procedure stands During the return time of the squared timber, there is usually enough time to Adjustment of the cutting devices available, then the squared timber to go back to work under new conditions.

The situation is different for a larger sequence of Cutting devices in which the squared timber is complete in one pass is divided into thin boards. Especially when processing relative short squared timbers, as is the case with the manufacture of parquet slats is, on the one hand the processing speed is so high that the Result of a thickness measurement of the residual squared timber at the exit of a Cutting machine for a setting correction on the following Cutting machine is no longer possible. One is therefore in such systems went another way, as described in DE 42 44 310 C1.  

In order to avoid that with the not exactly predictable cutting thickness on At the end of the dividing process, an undersized residual board remains, which you can lead to handling difficulties in the system anyway deliberately suggested to use starting timbers, which are a bit have greater thickness than the sum of the thicknesses from them generating boards. In this way, after passing through a square timber due to the sequence of cutting devices usually a rest board, the Thickness is greater than the target thickness. To make this board usable too make, provides the invention described in DE 42 44 310 C1, behind the sequence of cutting devices a device for cutting The thickness of the rest of the board should be reduced. Not this in itself Process-compliant treatment of the rest of the board was provided in order to such a system cannot be solved due to the short throughput time Avoiding control problems for the lossless division of a timber.

It has now been shown, in particular when producing parquet slats, that the product-like that occurs when cutting the squared timbers then also machine-related thickness deviations Difficulties in further processing can result if, as with the processing of cut slats only in the top layer of a Product a machining thickness reworking of the lamellas drying should be avoided as much as possible to avoid this post-processing solely as a final surface treatment of the already glued To provide product.

The invention is therefore based on the object for such Procedure of the slats leaving the cutting devices or thin To produce boards that already have a high thickness consistency.

Starting from a prior art, as described in DE 40 26 346 A1 is described, this problem is inventively by the  characterizing features of claim 1, in so far a method is affected, and by the characterizing features of claim 7 solved for a corresponding system.

The invention is based on the previous goal, that of a square timber measured residual thickness in measures for further division of this squared timber to implement. The primary goal is to record the exact thickness of the thin boards produced in each of the cutters. Deviates from a cutting device generated board thickness from the target thickness, in the assumption that in a production run essentially woods are the same Parameters are processed, the cutting thickness relevant parameters of this Cutting device, usually the distance of the knife from the Contact surface for the squared timber, corrected in such a way that it becomes thinner when separated Boards from the following squared timber, if possible, boards of nominal thickness or are generated within a predetermined tolerance.

Such a procedure is particularly advantageous if anyway behind a series of cutting machines that have a square timber in one Passage should completely divide a device, especially one Planing machine for cutting thickness reduction of the last machine leaving rest of the board is provided. In this case too, if possible should be striven to get a board, the thickness of which is greater than the rest of the board than the target thickness of a board to be produced, so that there is still a cutting Processing can be done in the planer. Basically it is however, by determining the thickness of the remaining squared timber before the last one intended cutting process to determine how this residual squared timber continues to be processed. Would the last intended cutting operation a remnant board remain, the thickness of which has a certain critical value falls below, there is a risk that such residual timber for the No more cutting off the last board from the cutting device can be guided and advanced accordingly. Is therefore at the exit  a remaining cutting board before a certain cutting machine, the thickness of which is between the target thickness of one board and the target thickness of two boards, so can this board is only subjected to a further cutting process, if the thickness of the residual squared timber is above a machine-related thickness Dx lies. If the thickness of the remaining squared timber or residual board is less than Dx, must this remaining board is fed directly to the downstream planing machine will. However, the thickness of the remaining squared timber is above Dx, but as a rule below the thickness D2 of two boards, the remaining squared timber can be one be subjected to further cutting, the then occurring The remaining board, however, should be discarded by being ejected because of its thickness is below the target thickness of a board to be produced. The appearance of this Condition should be avoided if possible, but for such a case no longer prefers a switch in front of the planer to discharge acceptable residual boards.

Since the number of cutting devices also in a plant in which a Squared timber can be completely divided into thin boards in one pass should or can, not necessarily with the number of squared timber producing boards must match, the system is preferably such to design that at least one or more of the cutting devices for passing through a squared timber without cutting off a board are, or that a residual square timber on a bypass conveyor on one or several cutting devices can be passed.

The sequence of the cutting process described here is preferably in one Entire process flow embedded in which the cut thin boards in a manner known per se after cutting to a certain final moisture dried and then as a top layer for a laminate product, in particular a floor covering can be used, one of the slats Compiled top layer with underlay layers of a certain thickness, for example sawn wooden bars, chipboard or the like. Under pressure  is glued, the lamellae after drying if necessary on their Reworked side edges, but preferably in their thickness, as created, be left. This saves a thickness processing step. As before mentioned above, the surface of the lamella top layer is already on glued product reworked. The possibility of a thickness calibration the lamellae by grinding after drying, but before Being able to omit further processing leads to material savings and Savings in abrasives.

It is expressly pointed out that in a series of Cutting devices do not necessarily produce lamellae of the same thickness have to. The inventive method provides that in particular Splitting a squared timber in one pass through a sequence of Cutting devices in the individual cutting devices also thin boards different thickness can be generated. In this case you move preferably creating the thickest boards desired in the last or the last cutters of a sequence because the Difficulties in handling the squared timber in the cutting machine can be reduced.

The determination of the thickness of the lamellae produced in each cutting device is preferably carried out by forming the difference from the thickness measurements in a Cutting device incoming as well as leaving (residual) squared timber. Since it makes sense in a preferred embodiment of the method, in the area the last of a series of cutting devices in any case also the Residual squares measure to make decisions about their further Processing is a good idea, at least in this area Difference measurement to be provided. A thickness measurement on the separated Boards themselves can be problematic and time-consuming because they are fresh produced a warp in the form of a curvature and / or  Have twist so that an alignment of the board surface on the Measuring point not exactly perpendicular to the direction of action of the sensor can be guaranteed. Straightening devices for the boards not always used. It also usually makes sense to keep the boards during of severing and then not in their lateral movement possibilities to hinder, so that measuring devices that the boards in certain, should feel a short distance from the outer edge, but not certain boards to capture. Exact guidance devices for the separated boards would require an additional investment for other reasons is not required.

The thickness measurement is preferably carried out in the area of the funding for the guiding of the (residual) squared timbers are provided. Find preferably Thickness measuring devices use, which is based on the laser beam principle serve. The thickness measurement is advantageously carried out at points where the thickness of the conveyor, for example a conveyor belt, is not is included. In the case of conveyor belts, for example, the belt can be used here be made narrower than the width of the squared timbers, so that this preferably protrude on each side of the conveyor belt to get into this To carry out the measurements, preferably in each case two measurements at a distance from the two side edges of the material to be conveyed respectively. The measuring point can also at an interruption point of the Funding may be arranged. When using a conveyor belt generate an interruption in that the conveyor belt briefly is diverted away from the material to be conveyed via deflection rollers and then to reunite with him. Also the point of transition from one Funding to the other can be used.

Further details are explained in more detail with reference to the exemplary embodiments shown schematically in FIGS. 1 to 4.

Show it:

Fig. 1 shows a plant comprising a cutting machine and circulated out wood residues,

Fig. 2 shows a plant with successively arranged cutting machines and einzügigem pass,

Fig. 3 shows a detail of the conveyor belt in the area of a thickness measuring device, and

Fig. 4 shows an alternative to FIG. 3.

The centerpiece of the plant for the production of parquet panels shown in FIG. 1 is the cutting device 1 , through which a squared timber or parquet frieze or the residual wood 5 is passed until it is finished. The transport route designated 6 is followed. The system also includes a planing machine 2 , a warming tunnel 3 and two thickness measuring devices 4.0 and 4.1 . The thickness of the parquet frieze or the residual wood 5 is measured before and after a parquet panel has been cut off. The difference between the measured values gives the actual thickness of the parquet panels, which is discharged from the system at 7 . If the actual thickness deviates from the target thickness D, the cutting thickness setting is corrected on the cutting device.

If the measurement after the cutting device 1 shows that the residual wood thickness S is greater than or equal to twice the nominal thickness D of the parquet panels, a further circulation or cutting process is carried out. If the residual wood thickness S <2 D but greater than Dx with Dx <D, the residual wood 5 is again fed to the cutting device 1 and the resulting residual board of thickness (Dx-D) is discarded. If the residual wood thickness S is less than Dx, the residual wood 5 is fed to the planing machine 2 and machined to the desired thickness D in a cutting process. The value Dx is chosen depending on the machine parameters and the type of wood so that a remaining board of the thickness (Dx-D) can still be detected and handled by the cutting device 1 without any problems. The finished parquet panels are discharged at 7.2 and the chips are removed from the hoisting machine 2 at 9 . In the event that the residual wood thickness S is exactly equal to D, you have a tailored parquet panel, which is removed from the system at 7.1 . If the measurement shows a residual wood thickness S <D, the residual wood is discharged at 8 as a reject. As soon as a parquet frieze has been finished, a new specimen is introduced from the warming tunnel 3 into the cutting device 1 , the necessary control signals also being based on the thickness measurement at 4.2 . Advantageously, there are always several pieces of wood 5 in circulation so that the cutting device 1 can be optimally used.

In the system of FIG. 2, the preparation of the floor panels in a single pass of the parquet frieze and the residual timber 5, whereby required for the preparation of n + 1 parquet panels from a floor Fries n cutting members and a planing machine 2. Only three cutting machines are shown, namely the first 1.1 , any intermediate stage 1. i and the last 1 .n. Correspondingly, the associated thickness measuring devices are designated 4.1 , 4 .i and 4 .n. In addition, a thickness measuring device 4.0 is also provided, with which the thickness of the parquet frieze is determined before entering the first cutting device 1.1 . At 7.1 , 7. i and 7. n, the parquet panels are removed from the system. The last parquet panels 5 a is removed from the planing machine 2 , regardless of whether the last measured residual wood thickness S is larger or the same size D. In the latter case, there is no longer any cutting thickness reduction. With 9 the removal of the chips and 8 the removal of residual wood with a thickness smaller than D is referred to as a reject.

Fresh parquet friezes of the first cutting device 1 are made from the warming tunnel 3 . 1 fed. In addition, the further processing of the residual wood 5 takes place in principle in the same way as described for the system according to FIG. 1, depending on the thickness measurement.

Fig. 3 shows a section perpendicular to the transport device. The parquet frieze or residual wood 5 is wider than the conveyor belt 10 , so that the thickness measurement by the transmitter 4 a and receiver 4 b existing thickness measuring device 4.0 , 4.1 can take place laterally past the conveyor belt 10 .

Another possibility of interference-free thickness measurement is shown in FIG. 4, in a side view of the area of the thickness measurement device 4.0 , 4.1 , which again consists of transmitter 4 a and receiver 4 b. The conveyor belt 10 , on the parquet frieze or residual wood 5 is transported from right to left (see arrow), is deflected via the rollers 11 , 12 , 13 , so that an area is created in which the receiver 4 b is accommodated and a trouble-free measurement can be carried out.

Claims (15)

1. A method for producing thin boards, in particular parquet slats, from a squared timber by repeatedly cutting a thin board from the squared timber without cutting in a cutting device or a sequence of cutting devices arranged one behind the other and repeatedly passing through the cutting device the residual squared timber which has not yet been completely divided into thin boards (en), but in particular in a sequence of cutting devices arranged one behind the other, in which the squared timber is divided into thin boards in one pass, the squared timber being moved against a generally stationary knife in the longitudinal direction of its fiber orientation in order to cut off a thin board, and at which takes place at least one thickness measurement during the passage of the squared timber through the cutting device (s), characterized in that the thickness of the thin boards produced by each individual cutting device ( 1 , 1.1 , 1. i, 1. n) is determined separately, the determined actual value of the thickness of the boards of a cutting device ( 1 , 1.1 , 1. i, 1. n) is compared with the target value of the thickness of the thin boards to be produced by this cutting device ( 1 , 1.1 , 1. i, 1. n) and a signal is obtained from a deviation from the nominal value of the thickness and is used for correcting the knife setting relevant to the cutting thickness of the relevant cutting device ( 1 , 1.1 , 1. i, 1. n) for separating thin boards from subsequent squared timbers. 2. The method according to claim 1, characterized in that the determination of the actual thickness of the thin boards produced in a cutting device ( 1 , 1.1 , 1. i, 1. n) as a difference in the thickness of the (residual) wood ( 5 ) before and after a thin board has been cut off. 3. The method according to claim 2, characterized in that a residual wood ( 5 ), the measured actual thickness is in the range above the target thickness D of a board to be produced and below a certain thickness Dx, which in turn is below the summed target thickness 2D of two boards to be produced , discharged from the cutting process and subjected to machining to reduce the thickness to the desired thickness D, and that a residual wood ( 5 ) whose measured actual thickness is between Dx and 2D is subjected to a further cutting process and the resulting residual board is discarded, the thickness Dx or the difference in thickness (Dx-D) is specified as a system-dependent value. 4. The method according to at least one of claims 1-3, characterized characterized that to correct the cutting thickness relevant Knife setting due to the thickness deviation of the measured generated thin boards of the target thickness D a control and Control device is used, which is a dependency of the Knife setting based on the board thickness for a certain type of wood and / or a certain wood condition can be specified, and / or which is capable of learning in such a way that it corrects knife adjustments takes into account the impact of previous corrections. 5. The method according to at least one of claims 1-4, characterized in that the thickness measurement of the thin boards or residual wood ( 5 ) is carried out by means of laser beams. 6. The method according to claim 5, characterized in that on each thin board or residual wood ( 5 ) two areas are measured at a distance from the outer longitudinal edges of the thin board or residual wood ( 5 ). 7. Plant for cutting thin boards without cutting from a squared timber with a cutting device ( 1 ) or a sequence of cutting devices ( 1.1 , 1 .i, 1 .n), means for feeding the squared timber to the cutting device (s) ( 1, 1.1 , 1 .i, 1 .n), optionally means for guiding the squared timber from one cutting device ( 1, 1.1 , 1 .i, 1. n) to the following and means for removing a residual board that can no longer be separated behind the cutting device ( 1 ) or behind a cutting device of the sequence of cutting devices ( 1.1 , 1. i, 1. n), means for pulling off ( 7.1 , 7. i, 7. n) a separated board from each cutting device ( 1, 1.1 , 1 . i, 1. n) and optionally means for returning a residual wood ( 5 ) from the exit of one or the last of a sequence of cutting devices ( 1, 1.1 , 1 .i, 1. n) to or in front of one of the preceding cutting devices ( en) ( 1, 1.1 , 1 .i, 1. n) if the number of cutting device en ( 1, 1.1 , 1 .i, 1. n) is less than the number of thin boards to be produced from a square timber, and at least one thickness measuring device ( 4.0, 4.1, 4. i, 4 .n) behind the cutting device ( 1 ) or behind the last one ( 1 .n) of a sequence of cutting devices ( 1.1 , 1 .i, 1. n) for measuring the thickness of the residual squared timber leaving this cutting device ( 1, 1.1 , 1 .i, 1. n) and a control device for the adjustment of the knife position (s) of the cutting device (s) ( 1, 1.1 , 1 .i, 1. n) depending on the measurement result of the at least one thickness measuring device ( 4.0, 4.1, 4. i, 4. n), thereby characterized in that each cutting machine is assigned a further thickness measuring device ( 4.0, 4.1, 4 .i, 4 .n), which either at its entrance for measuring a squared timber fed to the cutting machine or at the means for pulling off a cut board for measuring a cut board is arranged, and that the Steuereinrichtu ng is formed, from the actual thickness of the thin boards produced on each cutting device ( 1 , 1.1 , 1. i, 1. n), a comparison with a target thickness (D) of that in the respective cutting device ( 1, 1.1 , 1 .i , 1. n) thin boards to be produced in order to change the knife thickness relevant knife parameters on this cutting device ( 1, 1.1 , 1 .i, 1. n) for subsequent squared timbers if the actual value deviates from the target value. 8. Plant according to claim 7, characterized in that the means for removing a no longer divisible by cutting residual board from a cutting device ( 1 ) or the last of the sequence of cutting devices ( 1.1 , 1. i, 1. n) a device for cutting the thickness of the rest of the board, in particular a planer ( 2 ). 9. Plant according to claim 8, characterized in that between the one cutting device ( 1 ) or the last of the sequence of cutting devices ( 1.1 , 1. i, 1. n) and the device (planer 2 ) for machining post-processing of the rest of the board Switch ( 8 ) is arranged for discharging residual boards that no longer have the thickness of a thin board to be produced. 10. Plant according to at least one of claims 7-9, characterized in that in a sequence of cutting devices ( 1.1 , 1 .i, 1. n) one or more of the cutting devices ( 1.1 , 1 .i, 1. n) are formed to let a residual wood ( 5 ) pass without cutting off a thin board, or that one or more of the cutting devices ( 1.1 , 1 .i, 1. n) are assigned bypass means with which a residual wood ( 5 ) on the relevant cutting device ( 1.1 , 1 .i, 1. n) can be passed. 11. Plant according to at least one of claims 7-10, characterized in that the thickness measuring devices ( 4.0 , 4.1 , 4. i, 4. n) are laser beam devices. 12. Plant according to at least one of claims 7-11, characterized in that thickness measuring devices ( 4.0, 4.1, 4. i, 4. n) are arranged on the means for guiding the (residual) wood ( 5 ). 13. Plant according to claim 12, wherein the means for guiding conveyor belts ( 10 ), characterized in that the conveyor belts ( 10 ) are narrower at the location of the thickness measurement than the (residual) wood ( 5 ) or carried by them Board and the thickness measuring probes (transmitter 4 a, receiver 4 b) are arranged so that they capture the (residual) wood ( 5 ) or board at a point where it does not rest on the conveyor belt ( 10 ). 14. Plant according to claim 13, characterized in that the thickness measuring probes (transmitter 4 a, receiver 4 b) are arranged at an interruption point of the means for guiding. 15. Plant according to claim 14, in which the means for guiding conveyor belts, characterized in that the interruption point is a point at which the conveyor belt ( 10 ) is guided away from the conveyed material by diversion ( 11 , 12 , 13 ).