EP1672084B1 - Method and apparatus for automatically reworking of flexible non-metallic objects - Google Patents

Abstract

The machine (40) for working non-metallic and flexible materials, e.g. leather, has a trimming station (42) where sections are cut from a roll (66) of material as workpieces (64) to be passed to an automatic cutting station (44). The workpieces are cut out by a cup (48) or belt blade from above while the material is held in place by suction. Markings are applied to the workpiece to be registered at the cutting station for precision cutting of the workpiece outline.

Description

The invention relates to a method and a device for the automatic processing of non-metallic, yielding workpieces.

Devices for sharpening non-metallic, compliant workpieces, such as leather or synthetic leather, have long been known.

For sharpening thin, lobe-like materials, such as leather, synthetic leather and the like, bell knives are common, such as from DE 198 58 619 C1 , of the DE 199 29 977 C1 and the DE 35 36 220 C2 known.

The bell-shaped blade is arranged stationary in the respective device and is driven in rotation. The respective operator now has to guide the flap-like workpiece along the bell-shaped knife in order to either separate it (split) or to cut it (sharpen) at the edge in a suitable manner. The disadvantage of such an arrangement is of course the high manual effort, which is created by the targeted Entangenführen the workpiece on the bell. In addition, there is a risk that faulty cuts are generated, which may be the case in particular in the production of complicated shaped, curved cutting lines.

In a production line, the workpieces are first cut to the desired size and shape at one or more cutting stations and then sharpened at one or more sharpening stations as described above.

Overall, this results in a high effort through the many manually performed processing and transport operations.

From the DE 37 32 059 A1 and from the DE 199 29 977 C1 a device according to the preamble of claim 1 is known.

Thereafter, a material to be sharpened is guided along a stop with the aid of a feed roller against a rotating bell-shaped knife and thus cut or sharpened on its surface.

However, this does not allow automatic editing.

From the DE 1 250 960 B Further, a machine for cutting flap-like workpieces is known, in which a housing-fixed and immovable arm is provided, on which a horizontal axis is mounted for a swivel head, wherein a disc knife is provided for cutting the workpieces, and wherein above the plate knife provided a guide member is, which is arranged by means of a holder and a centering ring on the swivel head.

Such a device using a plate knife is not suitable for semi-automatic or automatic sharpening of a flap-like workpiece.

The invention is thus based on the object to provide a method and an apparatus for processing non-metallic, resilient workpieces, whereby a simplified machining of workpieces is possible.

This object is achieved by a method for processing non-metallic, yielding workpieces, in which the workpieces are first sharpened by means of a bell knife or band knife and then cut.

The cohesion of the material enables semi-automatic or automatic processing.

According to an alternative embodiment of the invention, which can be preferably combined with the aforementioned embodiment, the object is achieved by the sharpening by means of a motor-driven knife in the form of a bell knife or band blade, the material lying on the plan to be sharpened material from above to be led.

Also in this way results in a significant simplification of the processing, since so the sharpening of the workpieces can be done in full on a pad, which allows a semi-automatic or automatic guidance of the sharpening unit.

The sharpening process can then be followed by a preferably automatic cutting process.

According to a preferred embodiment of the method according to the invention, the material to be sharpened is depressed in the area of the knife which is not to be sharpened.

In this way, the sharpening process for elastic material is limited to the area that lies in the area of the knife and is not depressed.

Through the use of lying material this can be conveniently secured to a base while the sharpening unit is moved from above along. In this way, the sharpening process can be easily automated.

The knife is preferably guided automatically controlled during the sharpening process.

In a preferred embodiment of the invention, the workpieces of endless material (such as roll material) are produced, which is first sharpened, and from which the workpieces are separated by a subsequent cutting process.

In this way, the automatic machining is greatly simplified because the positioning of the workpieces is determined by the cohesion of the continuous material for the subsequent cutting process. This can be costly positioning omitted if necessary.

According to an alternative embodiment of the invention, the workpieces are first sharpened and provided with markings. These marks are used to control a subsequent cutting operation.

This allows automatic processing even of flap-like workpieces, such as skins made of leather, as can be guaranteed by the markings correct positioning and positioning errors can be corrected automatically.

According to a further embodiment of the method according to the invention, the material is held on the substrate during the sharpening process by means of vacuum assistance.

Preferably, in the area of the sharpening process, a pressing force of the workpiece, which is increased in relation to the other areas of the workpiece, is also produced on its base, which can be achieved in a relatively simple manner when using a vacuum table.

By these measures, it is prevented by a special attachment of the workpieces on a support table that the resilient material emigrated during the cut in the area of the knife.

With regard to the device, the object of the invention is achieved by a device for machining non-metallic, compliant workpieces, with at least one sharpening station for sharpening the workpieces, which has a motor-driven knife in the form of a bell knife, and a receiving table for supporting a workpiece, wherein the Knife is guided automatically movable at a sharpening unit above the receiving table and means are provided for holding down the workpiece on the support surface in the region of the knife.

The means for holding down the workpiece preferably comprise a hold-down in order to press the material to be processed in the region of the knife.

The hold-down device here are preferably associated adjusting means for adjusting its relative position with respect to the bell-type meter.

In this way, a clean sharpening process can be achieved even with lying material with a flat support surface.

In an advantageous embodiment of the invention, the support surface of the vacuum table is divided into a plurality of zones whose suction power is controllable in dependence on the position of the cutting unit.

In this way, the zone in the area where the cutting unit is currently located, can be operated with an increased suction power, so as to achieve a particularly strong holddown of the workpiece in the region of the cutting unit, so that a deflection of the workpiece relative to the knife is avoided.

According to a further embodiment of the invention, the vacuum table has a basic vacuum zone, with a first pressure difference which extends over a larger area of the support surface, and a movable vacuum zone which extends over a smaller area below the cutting unit, whose position is dependent on the Position of the cutting unit is locally controllable, and having a greater pressure difference than the first pressure difference.

With these features, a further improved suction of the workpiece to the support surface of the vacuum table can be achieved because the workpiece as a whole by means of the basic vacuum zone is sucked to the support surface with a certain suction and is additionally sucked in the area of the cutting unit with increased suction power.

In this case, valves can be provided for controlling the movable vacuum zone, which valves can be controlled mechanically or electronically as a function of the position of the cutting unit.

A mechanical control of the valves could, for example, be achieved by running along with the cutting unit below the support surface as a bar, of which the valves are actuated as about a Kipphebelsteuerung.

Another possibility is to form the valves as solenoid valves, which are controlled by an electronic control unit, which also controls the movement of the cutting unit. This is of course associated with significantly less mechanical effort than with a mechanical control.

According to a further embodiment of the invention, the support surface of the vacuum table is penetrated by a plurality of suction openings, which are preferably arranged in a grid.

Here, the suction openings are preferably arranged in a square grid, wherein the grid spacing between adjacent suction openings at most 15 millimeters, preferably at most 10 millimeters, more preferably less than 10 millimeters, for example. Be about 5 millimeters.

According to a further embodiment of the invention, the suction openings have a diameter of less than 1 millimeter, preferably less than 0.8 millimeter, for example. About 0.5 millimeters, on.

By these measures, the suction effect of the vacuum table can be improved or adapted so that even very flexible workpieces can be sucked with sufficient precision to avoid deflection of the workpiece in the region of the cutting point.

In an advantageous embodiment of the invention, an outflow opening for the outflow of compressed air in the direction of the workpiece is further provided in the region of the hold-down.

This measure supports a holddown of the workpiece in the region of the interface, whereby a deflection of the workpiece is further counteracted.

The cutting unit is in a preferred embodiment of the invention by means of an electronic control unit in three linear axes and automatically controlled to control a rotational axis.

In this way, different material thicknesses can be automatically taken into account and at the same time curved cuts are generated by the cutting unit is controlled in each case in a suitable angular position.

According to a further embodiment of the invention, the sharpening station has marking means for producing markings on the workpieces.

At a respective downstream cutting station can then be made with associated sensor means a correct positioning of the workpieces.

This allows a correct positioning of the workpieces for the cutting process in a particularly simple and precise manner. Automatic positioning or automatic correction of positioning errors is also possible. The marking agents may be agents which are generally known in the art, such as a marking device by means of an ink-jet printing technique or by means of laser technology.

Such markings may be omitted if continuous material (e.g., roll stock) is processed. This is therefore particularly preferred.

It is understood that the above-mentioned features can be used not only in the combination given, but also in other combinations or in isolation, without departing from the scope of the invention.

Fig. 1

eine erfindungsgemäße Vorrichtung in stark vereinfachter, schematischer Darstellung;

Fig. 2

eine abgewandelte Ausführung der Vorrichtung gemäß Fig. 1;

Fig. 3

eine Aufsicht einer erfindungsgemäßen Schärfstation in vereinfachter, schematischer Darstellung und

Fig. 4

einen Teilschnitt durch den Vakuumtisch gemäß Fig. 3 in vergrößerter Darstellung, bei dem zusätzlich die Schärfeinheit erkennbar ist.

Further features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawings. Show it:

Fig. 1

a device according to the invention in a highly simplified, schematic representation;

Fig. 2

a modified embodiment of the device according to Fig. 1 ;

Fig. 3

a plan view of a sharpening station according to the invention in a simplified, schematic representation and

Fig. 4

a partial section through the vacuum table according to Fig. 3 in an enlarged view, in which additionally the sharpening unit can be seen.

In Fig. 1 a device according to the invention is shown and designated overall by the numeral 10.

The apparatus 10 includes a sharpening station 12 followed by a cutting station 14 and a removal station 16.

Raw material appropriately controlled to its quality is first fed to the sharpening station 12 where it is mounted on a level surface and sharpened by means of a sharpening unit 18 which is automatically guided and positioned. As in Fig. 1 is indicated by arrows, the sharpening unit 18 can be controlled and positioned in the x-direction and Y-direction. The raw material is compliant workpieces, such as flap-like workpieces, such as leather, synthetic leather, paper, cardboard or the like.

The sharpening is done in full on a hard, level surface, without the material is completely severed.

In addition, the sharpening station 12 has a marking unit 20. This may be, for example, an intelligent inkjet marking unit, which is also in the x-direction and y-direction controlled to be moved to apply on the workpieces markings at appropriate positions, which allow precise positioning of the workpieces in the downstream cutting station 14.

After sharpening, the workpieces are preferably automatically transferred by means of a suitable transport device in the direction of the arrow 32 to the downstream cutting station 14 and then automatically positioned by means of suitable sensor means 31 using the previously applied markings. By way of example, four markings 22, 24, 26, 28 are indicated here, which can be read out by means of a movable sensor means 31. These markings are then used to position correction in the leadership of a cutting unit 30 in an automatic cutting process. The cutting unit 30 may be, for example, a laser cutting unit, a water jet cutting unit, a knife cutting unit, or any other cutting unit generally known in the art. If a knife cutting unit is used, a resilient flat bearing surface is used.

The cutting process produces individual workpieces which are completely automatically processed and which are removed and provided automatically or by hand at the downstream removal station 16 for further processing or for further transport.

In Fig. 2 is a variant of the embodiment according to Fig. 1 represented and designated overall by the numeral 40. Again, the device comprises a sharpening station 42, to which in Direction 62 of the material flow a cutting station 44 and a removal station 46 connect.

Unlike the version according to Fig. 1 However, no items are processed, but endless material in the form of roll material 66. For this reason, if necessary, can be dispensed with the application of marks and a subsequent reading of the marks. Due to the material cohesion of the roll material 66, the positioning in many applications, even in the cutting station 44 is ensured sufficiently precise. For high-precision applications, additional markings can be used as in the version according to Fig. 1 be used to ensure a high-precision guidance of the cutting unit 60 in the cutting station 44.

Additionally are in Fig. 2 some workpieces 64 are shown, which are separated from each other during the cutting process at the cutting station and then removed, for example by means of a handling device 68 of the removal station 46, for example by means of a suction device 70.

The construction of a sharpening station is now on hand of Figures 3 and 4 explained in more detail.

In Fig. 3 a sharpening station according to the invention is designated overall by the numeral 112. The sharpening station has a vacuum table 110, the bearing surface 114 of which is provided with a plurality of suction openings 116, which in the example shown are arranged in a square grid.

The vacuum table 110 serves to support and fix the workpieces.

For sharpening the workpieces is an in Fig. 3 provided in total with the numeral 126 indicated sharpening unit, which is equipped with a bell knife 148 (see. Fig. 4 ). The sharpening unit 126 is automatically guided guided in three coordinate directions (x, y, z) and additionally pivotable about an axis of rotation (r).

These are in accordance with Fig. 3 on the left and right sides of the vacuum table 110, a respective linear guide 128 or 132 is provided, which is arranged parallel to one another, on which slides 130 and 134 are guided. The two carriages 130, 134 are connected by a beam, which is likewise designed again as a linear guide 136 for a further slide 138. At least one of the two carriages 130, 134 can be driven by a motor, so that both carriages 130, 134 move synchronously, as indicated by the double arrows 140. On the linear guide 136 between the two carriages 130, 134, the carriage 138 is in turn controlled in the direction of the double arrow 142 along the linear guide 136 movable. On the carriage 138, a further linear guide in the vertical direction (z-direction) is added, on which the sharpening unit 126 is held, which is additionally pivotable about an axis of rotation, as indicated by the double arrow 144.

For automatic control of the position of the sharpening unit 126, an automatic control unit 118 is provided, which is preferably a microprocessor-controlled unit which is programmable. For example. it could be a PLC controller.

In Fig. 3 is indicated schematically that the control unit 118 is connected via lines 120, 124 with the drives for automatic positioning and also via a control line 122 to the vacuum table 110, in order to change the suction power of the vacuum table 110 can locally targeted in the manner described below.

The construction of the vacuum table 110 and the sharpening unit 126 will be described below with reference to FIG Fig. 4 explained in more detail.

As already mentioned, the support surface 114 of the vacuum table 110 is penetrated by a plurality of suction openings 116, which are arranged in a square grid. In this case, the distance a between adjacent suction openings 116, for example, be about 8 millimeters, while the diameter d of the suction openings 116, for example. 0.7 millimeters is (the drawing according to Fig. 4 is not necessarily to scale, but merely demonstrates the geometric relationships).

The bearing surface 114 of the vacuum table 110 is, as in Fig. 3 indicated by dividing lines, divided into a total of sixteen square zones q _ik . In Fig. 4 Of these two zones q ₁₂ and q _{22 are} visible in cross section. In each of these zones, twenty-five suction ports 116 are included in the illustrated case.

How out Fig. 4 can be seen, each zone q _ik by suitable partitions 166 airtight to adjacent zones and after closed down, so that in each case a suction chamber is formed. In Fig. 4 By way of example, such a suction chamber belonging to the zone q _{12 is} designated by the numeral 167.

Thus, all suction ports of each zone q _ik can be acted upon together with a certain negative pressure, while the other zones can be operated with a different negative pressure (the dividing lines in Fig. 3 indicate only the schematic division of the entire bearing surface 114 in the different zones; Partitions between adjacent zones preferably do not extend through suction openings, but conveniently between adjacent suction openings, as in FIG Fig. 4 shown).

The zone q ₁₂ is connected via a first valve 168 with a line 180 to a first vacuum pump 182 and further connected via a second valve 170 and a line 176 to a second vacuum pump 178.

In a corresponding manner, the remaining zones are each connected via two valves to the first and second vacuum pump. Thus, for example, the adjacent zone q _{22 is} connected via a valve 172 to the vacuum pump 182 and connected via a valve 174 to the vacuum pump 178.

In this way, the suction power of all sixteen zones q _ik can be controlled in a targeted manner. Preferably, this is done so that the zone above which the sharpening unit 126 is currently located, is operated with an increased suction power, while all other zones are operated with a lower suction power. For this purpose, for example, in the zone q _12, the solenoid valve 170, which is connected to the vacuum pump 178, while all other solenoid valves connected to this vacuum pump 178 are closed. At the same time, in this zone q _12, the other solenoid valve 168 connected to the vacuum pump 182 is closed, while all the remaining solenoid valves of the other zones connected to this vacuum pump 182 are opened.

This has the consequence that the suction chamber 167 of the zone q _{12 is} only aspirated via the vacuum pump 178, while all other suction chambers of all other zones are evacuated together via the vacuum pump 182. This results in the area of the zone q ₁₂ a greatly increased suction, while the other zones are operated evenly with a lower suction.

The control of the solenoid valves preferably takes place via the automatic control unit 118 as a function of the (known) position of the sharpening unit 126.

It goes without saying that, of course, the individual zones q _{ik can} also be made smaller in order to allow a more targeted adaptation of the increased suction power as a function of the position of the sharpening unit 126.

The sharpening unit 126 is different from conventional sharpening units according to the DE 198 58 619 Cl or the DE 199 29 977 C1 designed so that the sharpening is done on a flat support surface, and that the knife is guided in the form of a bell knife 148 from above the material to be sharpened along. The flat bearing surface assumes the function of the curved in the prior art guide foot. On the other Cutting edge (in the area of the bell blade 148), the sharpening shape is generated by one or more hold-down. In the illustrated case, two mirror-symmetrically arranged hold-downs 156, 157 are provided. The hold-downs 156, 157 are basically compressing elements that are designed as foot or roller-shaped elements. By the downholders 156, 157, the material is compressed to produce the desired sharpening shape. Since the sharpening is done in full, the elastic material is sharpened in the effective range of the bell blade 148 just where it is not depressed by the downers 156, 157. Because it stands out there and is cut or sharpened by the bell knife.

The hold-downs can, as indicated by adjusting means 155, be adjusted in their relative position to the bell knife 148. In addition, each hold-down device is additionally suitably adjustable (for example by a prismatic guide) in the vertical direction in order to be able to adjust automatically the setting height of the hold-down device, depending on the respective parameters.

The sharpening unit 126 has a base plate 146 which is held at the lower end of a vertical rod 145. The rod 145 can be moved in a manner not shown in the vertical direction (z-direction) controlled by a certain amount, as indicated by the double arrow 188. Further, the rod 145 can be pivoted about its longitudinal axis 185 by a certain angular amount, as indicated by the arrow 186. On the base plate 146 is a knife 148, which is designed as a bell knife, by means of a not shown Drive rotationally driven, as indicated by the arrow 150. Additionally, a grinding unit may be provided laterally on the base plate 146 with a grinding wheel 152 which is driven by a drive 154 and which is delivered to the rotary knife 148 as needed, as indicated by the double arrow 153, to sharpen and / or adhere it Clean dirt particles.

In addition, a compressed air line 60 is coupled via a screw 158 to the hold-down device 156. In the hold-down device 156 outlet openings 159 are provided, is blown through the supplied compressed air in the area on the interface to additionally hold down the workpiece 164 in the area of the interface. Although in the drawing, for simplicity, only one compressed air line 160 is shown for the hold-down 156, it is understood that preferably also the other hold-down 157 is coupled to a compressed air line to supply compressed air via outflow openings.

In Fig. 4 is on the grinding wheel 152 opposite side additionally below the base plate 146 nor a cover 162 shown, which serves as Berührschutz in the area of the bell blade 148.

All supply lines (compressed air and electrical lines) can, as in Fig. 4 indicated schematically, be led away in a common supply line 184 up to a suspension on which the rod 145 is held.

According to the invention, automatic sharpening and cutting of workpieces is made possible. It can on the one hand lobe-like Workpieces, such as. Leather pieces are processed. On the other hand, compliant endless material, such as roll material can be processed in order to produce in a particularly simple and cost-effective manner, for example, artificial leather pieces, such as are needed as a reference for dashboards, automatically.

Claims (20)

1. A method for processing non-metallic, yieldable workpieces (64; 164), characterized in that the workpieces (64; 164) are first scarfed by means of a bell knife or a band knife and are cut thereafter.
2. The method of claim 1, wherein the scarfing of the workpieces is performed into full on a flat support.
3. A method of processing non-metallic, yieldable workpieces (64; 164), in particular according to claim 1 or 2, wherein the scarfing is performed by means of a motor-driven knife (148) in the shape of a bell knife or a band knife which is guided along the material (66) to be scarfed from the top which is lying on a flat surface.
4. The method of claim 3, wherein the material to be scarfed is pressed down in the region of the knife (148) which is not to be scarfed.
5. The method of claim 3 or 4, wherein the knife (148) is guided automatically controlled during scarfing.
6. The method of any of claims 2 to 5, wherein the workpieces (64; 164) are cut out by a subsequent cutting operation out of endless material (66) which is first scarfed.
7. The method of claim 2, 3, 4, 5 or 6, wherein the workpieces (64; 164) are first scarfed and are provided with markings which are used for controlling the subsequent cutting operation.
8. The method of any of the preceding claims, wherein the material during scarfing is held on a support by means of vacuum assistance.
9. The method of claim 8, where in the region of the scarfing process a pressing force is generated for pressing the workpiece (64; 164) onto its support, the pressing force being enhanced with respect to the remaining regions of the workpiece (64; 164).
10. A device for processing non-metallic, yieldable workpieces (64; 164) for scarfing the workpieces (64; 164) by means of a motor-driven knife in the shape of a bell knife, further comprising a support table (110) for supporting a workpiece (64; 164), characterized in that the knife (148) is guided automatically movable on a scarfing unit (18; 48; 126) above the support table (110), and wherein a means is provided for holding down the workpiece (64; 164) on the support surface (114) in the region of the knife (148).
11. The device of claim 10, characterized by at least one cutting station (14; 44) for cutting the workpieces (64; 164), wherein the cutting station (14; 44) is arranged downstream of the scarfing station (12; 42; 112), seen in the transport direction (32; 62) of the workpieces (64; 164).
12. The device of claim 10 or 11, characterized in that the scarfing unit (18; 48; 126) is guided automatically movable at least in one plane (x, y) parallel to a support surface (114) of the vacuum table (110).
13. The device of claim 10, 11 or 12, characterized in that the support surface is configured as a vacuum table (110) which comprises a support surface (114) which is divided into a plurality of zones (q_ik) the section power of which is controllable depending on the position of the scarfing unit (18; 48; 126).
14. The device of claim 13, characterized in that the vacuum table (110) comprises a basic vacuum zone having a first pressure differential extending across a larger part of the support surface, while further comprising a movable vacuum zone (q_ik) which extends across a smaller part below the scarfing unit (18; 48; 126), the position of which is controllable depending on the position of the scarfing unit (18; 48; 126) and which further has a larger pressure differential than the first pressure differential.
15. The device of claim 13 or 14, characterized in that valves (168, 170, 172, 174) are provided for controlling the movable vacuum zone (q_ik), the valves being mechanically or electronically controllable depending on the position of the scarfing unit (18; 48; 126).
16. The device of claim 15, wherein setting means (155, 161) are assigned to the downholder (156, 157) for setting the relative position with respect to the bell knife (148).
17. The device of any of claims 10 to 16, characterized in that in the region of the downholder (156, 161) outlet openings (159) are provided for releasing pressurized air into the direction of the workpiece (64; 164).
18. The device of any of claims 10 to 17, characterized in that the scarfing unit (18; 48; 126) is automatically movable by means of an electronic control unit (118) in three linear axes (x, y, z) and about a rotary axis (r).
19. The device of any of claims 10 to 18, characterized in that the scarfing station (12) comprises marking means for generating marks on the workpieces.
20. The device of any of claims 11 to 19, characterized in that the cutting station (14) comprises sensor means (31) being configured for detecting marks (22, 24, 26, 28) generated in the scarfing station (12).

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