Method for machining the edges of flat plate-shaped workpieces

Abstract

The device for processing the edges (4) of plate-shaped workpieces (3) comprises a conveying circuit (1) including a processing section (2) for processing the edges (4), which is designed such that the workpieces (3) can be conveyed multiple times along the processing section (2) for processing the edges (84), and a feeding device (5) for feeding the workpieces (3) into the conveying circuit (1). The feeding device (5) is configured to determine the sequence in which the workpieces (3) are fed into the conveying circuit (1) depending on the dimensions of the workpieces (3).

Description

[0001] The invention relates to a method for processing edges of plate-shaped workpieces, according to the preamble of claim 1. Such a method is known from document DE 20 2009 006536 U1.

[0002] Such sheet-like workpieces are used particularly in the furniture industry. There, wood-based materials, but also wood-containing materials such as particleboard, are processed. Sheet-like intermediate products, which are usually already coated on their flat sides, are first cut to the desired format for further processing and then processed on their narrow sides, which specifically involves applying suitable coatings to the narrow sides, referred to below as edges.

[0003] This edge processing of the sheet-shaped workpieces, cut to the desired format, often takes place in so-called edge processing units. These units consist of a conveyor system in which the workpieces can be conveyed multiple times along a processing path for edge processing. According to the current state of the art, the workpieces are fed individually into the conveyor system and circulated until the processing of all edges of the respective workpiece is completed, at which point they are removed from the conveyor system.

[0004] A disadvantage of known conveyor systems is that the individual edge processing units along the conveyor circuit, as well as the conveying devices that are part of the conveyor circuit, can process or convey sheet-shaped workpieces of different dimensions at different speeds. Therefore, optimizing the throughput of the individual components of such a system is only possible to a limited extent, since sheets of varying dimensions are regularly processed in these systems. That is, if the individual units are designed to process sheets of a specific dimension in such a way that the capacities are coordinated to prevent any bottlenecks or congestion in the conveyor circuit, this coordination no longer applies when workpieces of other dimensions are to be processed.This can lead to a bottleneck, for example, in front of a processing unit, because this unit can no longer process workpieces with the new dimensions at the same speed as workpieces with the old dimensions, while the other components of the conveyor system continue to achieve their original processing capacity. DE 20 2009 006 536 U1 discloses a device in which the different workpieces are held in buffers and sorted and grouped so that uniform workpieces are processed sequentially by the subsequent machine, thereby reducing setup times and increasing throughput. The workpieces, which are circulated in a loop, are buffered after each processing step and then reassembled in an optimized configuration for the next processing machine. While this increases the utilization of the individual processing machines, it results in potentially different throughput times for the individual workpieces.

[0005] The invention is therefore based on the objective of demonstrating a method for processing edges of plate-shaped workpieces, which enables a uniform utilization of all individual elements of the device used for this purpose and thus an optimal utilization of the entire device.

[0006] The problem is solved by a device and a method according to the independent claims.

[0007] The method according to the invention provides for recording the dimensions of the workpieces before they are fed into the conveying circuit and for determining the sequence in which the workpieces are fed into the conveying circuit depending on the recorded dimensions of the workpieces. A suitable device for this purpose has a feeding device which is configured to determine the sequence in which the workpieces are fed into the conveying circuit depending on the dimensions of the workpieces.

[0008] By determining the feeding sequence depending on the dimensions of the workpieces, it is possible to select the feeding sequence of the conveying circuit in such a way that all elements of the conveying circuit and all processing devices provided for this conveying circuit are evenly utilized.

[0009] For example, if one element of the conveyor system operates in such a way that a certain number of pieces can be processed per unit of time, and another element operates in such a way that a certain running distance (edge ​​length) can be processed per unit of time, then the workpieces are arranged so that workpieces with short edges follow those with long edges, and vice versa. This prevents the unit capable of handling a specific number of workpieces per unit of time from being underutilized due to a build-up of workpieces with long edges in front of the unit capable of processing a specific edge length per unit of time.Conversely, this prevents underutilization of the facility, which can process a certain edge length per unit of time, when a large number of workpieces with short edges follow one another in direct succession, while workpieces accumulate in front of a facility that can handle a certain number of workpieces per unit of time.

[0010] In addition to the lengths of the edges, other dimensions, such as the thickness of the workpieces or their surface area, can also be taken into account.

[0011] Advantageously, the conveying circuit is designed such that one edge of a workpiece is processed at a time when it is conveyed along a processing section—that is, a segment of the conveying circuit where the edge is processed by a processing unit. To enable the processing of all workpiece edges without requiring a number of processing sections in the conveying circuit corresponding to the number of edges of the workpiece, it is useful to change the orientation of the workpiece relative to the processing section between two conveying cycles along this section. In this way, the processing units engage a different edge of the workpiece with each conveying cycle.

[0012] It is also possible to consider the orientation of the workpieces during coating, i.e., to feed the workpieces into the conveyor system in an orientation that takes into account the different processing capacities. This is useful, for example, when elongated workpieces with one pair of long edges and one pair of short edges are to be processed. If these are fed into the conveyor system in such a way that one of the longer edges of one workpiece alternates with one of the shorter edges of the following workpiece, and vice versa, then with each conveying of a certain number of workpieces along the processing path, a uniform average ratio between the edge length to be processed and the number of pieces is achieved. This would not be the case if the long edges of all workpieces were processed first, and then, in a subsequent pass of the conveyor system, the short edges of each individual workpiece were processed.This would result in a significant change in the ratio of the edge length to be processed to the number of workpieces between the two passes of the conveyor circuit, which in turn would lead to an overload of the capacities of individual units while simultaneously underutilizing other units.

[0013] According to the invention, the workpieces are fed into the conveyor system in groups. This group feeding is achieved using a sorting station in which the workpieces are initially grouped together in such a way that the dimensions relevant to the conveyor system's capacity are, as far as possible, constant on average within each group. This means that the grouping is arranged to minimize variations in dimensions from one group to the next, thus avoiding, for example, the formation of a group consisting solely of very small workpieces, i.e., workpieces with a high ratio of quantity to edge length. For this purpose, a rectangular grid is used in the sorting station, in which the workpieces are arranged into patterns.

[0014] The Figure 1 shows a schematic representation of an exemplary device for carrying out the method according to the invention.

[0015] Conveyor circuit 1 consists of two counter-rotating conveyors 8 and 9, and two transfer units 12 and 13, which can transfer workpieces from one conveyor to the other. Conveyor 8 runs alongside a processing machine (not shown); that is, a section of conveyor 8 forms the processing path 2.

[0016] If the conveying circuit includes means (not shown) for changing the orientation of the workpieces between their passes through processing section 2, processing section 2 can be designed such that only one edge 4 of the workpiece is processed per conveying of a workpiece through the processing section. The workpiece then passes through transfer unit 12, the second conveyor 9, and transfer unit 13, after which it returns to conveyor 8 and is conveyed through the processing section once more. If the orientation of the workpiece is changed between conveying points along processing section 2, a different edge 4 of the respective workpiece 3 is processed. The means for changing the orientation of the workpieces 3 can, in principle, be located at any position in the conveying circuit.Once all edges of the respective workpiece 3 have been processed after a corresponding number of passes through the conveyor circuit 1, the workpieces 3 are removed from the conveyor circuit 1. A removal station (not shown) may be provided for this purpose, which can be located at any point in the conveyor circuit 1. In the example shown, the conveyor 9 is designed so that it can convey the workpieces 3 beyond the transfer point with the translator 13, so that a section of the conveyor 9 no longer belongs to the conveyor circuit 1, but rather represents a removal section from which the workpieces can be taken.

[0017] According to the invention, the feeding device comprises a feeding station 6 and a sorting station 7. In the sorting station 7, the workpieces are grouped according to their dimensions; in the example shown, these are groups of four workpieces each, which are arranged in a rectangular grid to form so-called images and fed in groups by the feeding station 6 to the conveyor circuit 1.

[0018] In conveying circuit 1, the workpieces first enter singulation station 11, which separates the workpieces 3 that are fed in groups before they are individually conveyed and processed by conveyor 8 along conveying line 2. A collection station 10 follows conveyor 8, where the separated workpieces 3 are regrouped. These groups are then transferred to the transfer unit 12, conveyed back by conveyor 9, and fed back to singulation station 11 by transfer unit 13.

Claims

1. Method for machining the edges (4) of plate-shaped workpieces (3), wherein the workpieces (3) are delivered into a conveyor circuit (1), moved repeatedly along a machining line (2) for machining the edges (4) of the workpieces (3) and are removed from the conveyor circuit (1) once machining has taken place, wherein the dimensions of the workpieces (3) are measured prior to their delivery into the conveyor circuit (1) and the sequence in which the workpieces (3) are supplied to the conveyor circuit (1) is fixed in dependence on the measured dimensions of the workpieces (3), wherein the workpieces (3) are placed together in groups according to the fixed sequence and supplied group by group to the conveyor circuit (1), and wherein in the conveyor circuit the workpieces supplied in groups are first singled out individually before they are individually moved by the conveyor (8) along the conveyor line (2) and machined, characterised that the workpieces (3) are placed together group by group in a sorting station (7) and are delivered arranged in a plane in a rectangular grid group by group through a loading station (6) to the conveyor circuit (1).

2. Method according to Claim 1 characterised in that the dimensions comprise the lengths of the edges and / or the thicknesses of the workpieces (3).

3. Method according to Claim 1 or 2 characterised in that as each workpiece (3) is conveyed along the machining line (2) one edge (4) each of the respective workpiece (3) is machined.

4. Method according to one of Claims 1 to 3 characterised in that between each two conveyances of one workpiece (3) along the machining line (2) the orientation of the workpiece (3) is changed so that different edges (4) of the workpiece (3) can be machined during the two conveyances.

5. Method according to one of Claims 1 to 4 characterised in that once machined the individual workpieces (3) are placed back together into groups.

6. Method according to one of Claims 1 to 5 characterised in that the orientation in which the workpieces (3) are delivered to the conveyor circuit (1) is fixed in dependence on the measured dimensions of the workpieces (3), wherein the loading sequence is selected so that there is a uniform loading of all the machining devices provided in this conveyor circuit (1).

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